Glossary Of Environmental Science

 

Corporate Social Responsibility integration of social and environmental policies into day-to-day corporate business.

covenants formal agreements or contracts, often between government and industry sectors. The national packaging covenant and sustainability covenants are examples of voluntary covenants with a regulatory underpinning. Land covenants protect land for wildlife into the future.

crop coefficient (Kc) (water management) a variable used to compute the evapotranspiration of a plant crop based on that of a reference crop.

crop evapotranspiration (ETc) (water management) is the crop water use the regular water withdrawal.

crop rotation (crop sequencing) the practice of growing a series of dissimilar types of crops in the same space in sequential seasons for various benefits such as to refrain the build up of pathogens and pests that often occurs when one species is continuously cropped.

crude oil naturally occurring mixture of hydrocarbons under normal temperature and pressure.

cullet the term used to describe crushed glass that is suitable for recycling by glass manufacturers.

cultural eutrophication – the process that speeds up natural eutrophication because of human activity.

cultural services the non-material benefits of ecosystems including refreshment, spiritual enrichment, knowledge, artistic satisfaction.

culture ECM altering existing mass media to criticise itself (e.g. defacing advertisements with an substitute message). Public activism opposing commercialism as tiny more than propaganda for established interests, and the attempt to find substitute expression.

culvert drain that passes under a road or pathway, might be a pipe or other conduit.

cut and fill removing soil from one place to another, generally mechanically.

cyanobacteria (Cyanophyta or blue-green algae) a phylum of bacteria that obtain their energy through photosynthesis.

cyclone intense low pressure weather systems; mid-latitude cyclones are atmospheric circulations that rotate clockwise in the Southern Hemisphere and anti-clockwise in the Northern Hemisphere and are generally associated with stronger winds, unsettled conditions, cloudiness and rainfall. Tropical cyclones (which are called hurricanes in the Northern Hemisphere) cause cause storm surges in coastal areas.

D

DDT – a chlorinated hydrocarbon used as a pesticide that is a continual biological pollutant.

debt-for-Nature Swap – a financial transaction in which a portion of a developing nation’s foreign debt is forgiven in exchange for local investments in conservation measures.

decomposers consumers, mostly microbial, that change dead biological matter into minerals and heat.

deforestation – the conversion of forested areas to non-forest land for agriculture, urban use, development, or wasteland.

dematerialisation decreasing the consumption of materials and resources while maintaining calibre of life.

desalination producing potable or useful water by removing salts from salty or brackish water. This is done by three methods: distillation/freezing; reverse osmosis using membranes and electrodialysis; ion exchange. At present, all these methods are energy intensive.

desert an area that receives an average annual precipitation of less than 250 mm (10 in) or an area in which more water is lost than falls as precipitation.

desertification – the degradation of land in arid, semi arid and dry sub-humid areas resulting from various climatic variations, but primarily from human activities.

detritivore (detritus feeder) – animals and plants that consume detritus (decomposing biological material), and in doing so contribute to decomposition and the recycling of nutrients.

detritus – non-living particulate biological fabric (as opposed to dissolved biological material).

developing countries development of a country is measured using a mix of economic factors (income per capita, GDP, degree of contemporary infrastructure (both physical and institutional), degree of industrialisation, proportion of economy devoted to agriculture and natural resource extraction) and social factors (life expectancy, the rate of literacy, poverty). The UN-produced Human Development Index (HDI) is a compound indicator of the above statistics. There is a strong correlation between low income and high population growth, both within and between countries. In developing countries, there is low per capita income, widespread poverty, and low capital formation. In developed countries there is continual economic growth and a relatively high standard of living. The term is rather value-laden and prescriptive as it implies a natural transition from ndeveloped to eveloped. Even though poverty and physical deprivation are clearly undesirable, it does not follow that it is therefore desirable for ndeveloped economies to move towards affluent Western-style eveloped free market economies. We have tended to use the terms ndustrialised and on-industrialised even though these too can be misleading.

dfE design for the environment; dfE thinks about ‘cradle to grave’ costs and benefits associated with fabric acquisition, manufacture, use, and disposal.

dfM design for manufacturing; designing products in such a way that they are simple to manufacture.

dfS design for sustainability; an integrated design approach aiming to achieve both environmental calibre and economic efficiency through the redesign of industrial systems.

dfX design for assembly/disassembly, re-use. recycle.

dieback (arboriculture) a condition in trees or woody plants in which peripheral parts are killed, either by parasites or due to conditions such as acid rain.

dietary energy supply food acquirable for human consumption, generally expressed in kilocalories per mortal per day.

dioxin – any one of a number of chemical compounds that are continual biological pollutants and are carcinogenic.

distributed water (water management) bought water supplied to a user; this is generally through a reticulated mains system (but also through pipes and open channels, irrigation systems supplied to farms).

diversion rate (waste disposal) the proportion of a potentially useful fabric that has been diverted out of the waste disposal stream and therefore not directed to landfill.

divertible resource (water management) the proportion of water runoff and recharge that can be accessed for human use.

downcycling (waste management) recycling in which the calibre of an item is diminished with apiece recycling.

downstream those processes occurring after a specific activity e.g. the transport of a manufactured product from a works to the wholesale or retail outlet cf. upstream.

drainage (water management) that part of irrigation or rainfall that runs off an area or is lost to deep percolation.

drawdown (water management) drop in water level, generally applied to wells or bores.

dredging – (water management) the repositioning of soil from an aquatic environment, using specialized equipment, in order to initiate infrastructural and/or ecological improvements.

drift net – a type of fishing net used in oceans, coastal seas and freshwater lakes.

drinking water (potable water) water fit for human consumption in accordance with World Health Organisation guidelines.

drip irrigation (water management) a drip hose put approach the plant roots so minimising deep percolation and evaporation.

driver (ecology) any natural or human-induced bourgeois that directly or indirectly causes a change in an ecosystem. A direct driver is one that unequivocally influences ecosystem processes and that can be measured.

drop-off centre (waste management) a location where discarded materials can be left for recycling.

drought an acute water shortage relative to availability, supply and demand in a specific region. An extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation.

dryland salinity – (water management) accumulation of salts in soils, soil water and ground water; might be natural or induced by land clearing

E

eco- – a prefix now added to many words indicating a general consideration for the environment e.g. ecohousing, ecolabel, ecomaterial.

eco-asset a biological calibre that provides financial value to private land owners when they are maintained in or restored to their natural state.

ecolabel – seal or logo indicating a product has met a certain environmental or social standards.

ecological deficit – of a country or region measures the amount by which its Ecological Footprint exceeds the ecological capacity of that region.

Ecological Footprint (Eco-footprint, Footprint) a degree of the area of biologically productive land and water needed to produce the resources and absorb the wastes of a population using the prevailing technology and resource management schemes; a degree of the consumption of renewable natural resources by a human population, be it that of a country, a region or the whole world given as the total area of productive land or sea required to produce all the crops, meat, seafood, wood and fibre it consumes, to sustain its energy consumption and to give space for its infrastructure.

ecological niche – the surroundings of a species or population within its ecosystem.

ecological succession – the more-or-less predictable and orderly changes in the composition or structure of an ecological community with time.

ecological sustainability – the capacity of ecosystems to preserve their fundamental processes and operate and to retain their biological diversity without impoverishment.

ecologically sustainable development – using, conserving and enhancing the human community’s resources so that ecological processes, on which all life depends, can be maintained and enriched into the future.

ecology – the scientific study of living organisms and their relationships to one another and their environment; the scientific study of the processes regulating the distribution and abundance of organisms; the study of the design of ecosystem structure and function.

economic externalities costs or benefits that are not borne by the producer or supplier of a good or service. In many environmental situations environmental deterioration might be caused by a few while the cost is borne by the community; examples would include overfishing, pollution (e.g. production of greenhouse emissions that are not compensated for in any way by taxes etc.), the environmental cost of land-clearing etc.

ecoregion – (bioregion) the next smallest ecologically and geographically defined area beneath “realm” or “ecozone”.

ecosystem boundary the spatial delimitation of an ecosystem generally based on discontinuities of organisms and the physical environment.

ecosystem services – the role played by organisms, without charge, in creating a healthy environment for human beings, from production of oxygen to soil formation, maintenance of water calibre and much more. These services are now generally divided into four groups, supporting, provisioning, regulating and cultural.

ecosystem – a dynamic complex of plant, animal and microorganism communities and their non-living environment all interacting as a functional unit.

e-cycling recycling electronic waste.

effective rainfall the volume of rainfall passing into the soil; that part of rainfall acquirable for plant use after runoff, leaching, evaporation and foliage interception.

energy efficiency – using less energy to supply the same level of energy service.

effluent – a discharge or emission of liquid, gas or other waste product.

El Nio – a warm water current which periodically flows southwards along the coast of Ecuador and Peru in South America, replacing the generally cold northwards flowing current; occurs once each five to seven years, generally during the Christmas season (the study refers to the Christ child); the opposite phase of an El Nio is called a La Nia.

embodied energy – the energy expended over the entire life cycle of a good or service cf. emergy.

emergent property a property that is not evident in the individual components of an thing or system.

emergy nergy memory all the acquirable energy that was used in the work of making a product directly and indirectly, expressed in units of one type of acquirable energy (work previously done to supply a product or service); the energy of one type required to make energy of another.

emission standard – a level of emissions that, under law, might not be exceeded.

emissions intensity emissions expressed as quantity per monetary unit.

emissions trading see carbon trading.

emissions – substances such as gases or particles discharged into the region as a result of natural processes of human activities, including those from chimneys, elevated point sources, and tailpipes of motor vehicles.

endangered species a species which is at risk of fitting extinct because it is either few in number, or threatened by changing environmental or predation parameters.

energetics the study of how energy flows within an ecosystem: the routes it takes, rates of flow, where it is stored and how it is used.

energy – a property of all systems which can be turned into heat and measured in heat units.

* acquirable energy energy with the potential to do work (exergy);

* delivered energy energy delivered to and used by a household, generally gas and electricity;

* direct energy – the energy being currently used, used mostly at domestic (delivered energy) and for fuels used mainly for transport;

* embodied energy – t the energy expended over the entire life cycle of a good or service OR the energy involved in the extraction of basic materials, processing/manufacture, transport and disposal of a product OR the energy required to supply a good or service;

* geothermal energy heat emitted from within the Earth crust as hot water or steam and used to generate electricity after transformation;

* hydro energy potential and kinetic energy of water used to generate electricity;

* indirect energy the energy generated in, and accounted for, by the wider economy as a consequence of an agent actions or demands;

* kinetic energy – the energy possessed by a body because of its motion;

* nuclear energy – energy released by reactions within atomic nuclei, as in nuclear fission or fusion (also called atomic energy);

* operational energy the energy used in carrying out a specific operation;

* potential energy the energy possessed by a body as a result of its position or condition e.g. coiled springs and charged batteries have potential energy;

* primary energy forms of energy obtained directly from nature, the energy in raw fuels(electricity from the grid is not primary energy), used mostly in energy statistics when compiling energy balances;

* solar energy solar irradiation used for hot water production and electricity generation (does not include passive solar energy to heat and cool buildings etc.);

* secondary energy primary energies are transformed in energy conversion processes to more convenient secondary forms such as electrical energy and cleaner fuels;

* stationary energy that energy that is other than transport fuels and fugitive emissions, used mostly for production of electricity but also for manufacturing and processing and in agriculture, fisheries etc.;

* tidal/ocean/wave energy mechanical energy from water movement used to generate electricity;

* useful energy acquirable energy used to increase system production and efficiency;

* wind energy kinetic energy of wind used for electricity generation using turbines

energy bookkeeping measuring value by the energy input required for a good or service. A form of bookkeeping that builds in a degree of our affect on nature (rather than being restricted to human-based items).

energy audit – a systematic gathering and analysis of energy use information that can be used to determine energy efficiency improvements. The Australian and New Sjaelland Standard AS/NZS 3598:2000 Energy Audits defines three levels of audit.

Energy Footprint – the area required to supply or absorb the waste from coal, oil, gas, fuelwood, nuclear energy and hydropower: the Fossil Fuel Footprint is the area required to sequester the emitted CO2 taking into statement CO2 absorption by the sea etc.

energy management – A program of well-planned actions aimed at reducing energy use, recurrent energy costs, and detrimental greenhouse gas emissions.

energy recovery the productive extraction of energy, generally electricity or heat, from waste or materials that would otherwise have gone to landfill.

energy-for-land ratio – the amount of energy that can be produced per hectare of ecologically productive land. The units used are gigajoules per hectare and year, or GJ/ha/yr. For fossil fuel (calculated as CO2 assimilation) the ratio is 100 GJ/ha/yr.

enhanced greenhouse effect – the increase in the natural greenhouse effect resulting from increases in atmospheric concentrations of greenhouse gases due to emissions from human activities.

ENSO (El Nioouthern Oscillation) a suite of events that occur at the time of an El Nio; at one extreme of the cycle, when the central Pacific Ocean is warm and the atmospheric pressure over Australia is relatively high, the ENSO causes drought conditions over orient Australia cf. El Nio, Southern Oscillation.

environment – the external conditions, resources, stimuli etc. with which an organism interacts.

environmental flows – river or creek water flows that are allocated for the maintenance of the waterway ecosystems.

environmental indicator – physical, chemical, biological or socio-economic degree that can be used to assess natural resources and environmental quality.

environmental movement (environmentalism) – a term that sometimes includes the conservation and green movements; a diverse scientific, social, and political movement. In general terms, environmentalists suggest the sustainable management of resources and stewardship of the natural environment through changes in public policy and individual behavior. In its recognition of humanity as a participant in ecosystems, the movement is centered around ecology, health, and human rights.

environmental science – the study of interactions among physical, chemical, and biological components of the environment.

epidemiology – the study of factors affecting the health and illness of populations, and serves as the foundation and logic of interventions prefabricated in the interest of public health and preventive medicine.

erosion – displacement of solids (sediment, soil, rock and other particles) generally by the agents of currents such as, wind, water, or cover by downward or down-slope movement in response to gravity or by living organisms.

Escherichia coli (E. coli) a bacterium used as an indicator of soiled contamination and potential disease organisms in water.

estuary – a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea.

ethical consumerism – buying things that are prefabricated ethically i.e. without harm to or exploitation of humans, animals or the natural environment. This generally entails favoring products and businesses that take statement of the greater good in their operations.

ethical living adopting lifestyles, consumption and shopping habits that minimise our negative impact, and maximise our positive affect on people, the environment and the economy cf. consumer democracy, sustainable living.

eutrophication – the enrichment of waterbodies with nutrients, primarily nitrogen and phosphorus, which stimulates the growth of aquatic organisms.

eutrophication – an increase in chemical nutrients, typically compounds containing nitrogen or phosphorus, in an ecosystem.

euxenic – with extremely low oxygen cf. anoxic.

evaporation water converted to water vapour.

evapotranspiration (ET) the water evaporating from the soil and transpired by plants.

e-waste – electronic waste, particularly mobile phones, TVs and individualized computers.

extended producer responsibility (EPR) (product take-back) – a stipulation (often in law) that producers take back and accept responsibility for the responsible disposal of their products; this encourages the design of products that can be easily repaired, recycled, reused or upgraded.

external water footprint the embodied water of imported goods cf. internal water footprint.

externality (environmental economics) by-products of activities that affect the well-being of people or alteration the environment, where those impacts are not reflected in market prices. The costs (or benefits) associated with externalities do not enter standard cost bookkeeping schemes. The environment is often cited as a negatively affected externality of the economy (see economic externality).

extinction event – (mass extinction, extinction-level event, ELE) – a sharp decrease in the number of species in a relatively short period of time.

extinction – the cessation of existence of a species or group of taxa, reducing biodiversity.

F

feedback flow from the products of an action back to interact with the action.

feedlot (feedyard) – a type of Confined Animal Feeding Operation (CAFO) (also known as “factory farming”) which is used for finishing livestock, notably beef cattle, prior to slaughter.

fertigate apply fertiliser through an irrigation system.

fertility rate – number of live births per 1,000 women aged 15 to 44 years cf. birth rate, mortality rate.

fertilizers (also spelled fertilisers) – compounds given to plants to promote growth; they are generally applied either through the soil, for uptake by plant roots, or by foliar feeding, for uptake through leaves.

flyway – the flight paths used in bird migration. Flyways generally span over continents and often oceans.

food chain (food webs, food networks and/or trophic networks) – describe the feeding relationships between species within an ecosystem.

food miles – the emissions produced and resources needed to transport food and drink around the globe.

food security – global food security refers to food produced in adequate quantity to meet the full stipulations of all people i.e. total global food supply equals the total global demand. For households it is the capability to purchase or produce the food they need for a healthy and active life (disposable income is a crucial issue). Women are typically gatekeepers of household food security. For national food security, the focus is on adequate food for all people in a nation and it entails a combination of national production, imports and exports. Food security always has components of production, access and utilisation.

Footprint (Ecological Footprint) in a very general environmental sense a “footprint” is a degree of environmental impact. However, this is generally expressed as an area of productive land (the footprint) needed to counteract the impact.

forage – the plant fabric (mainly plant leaves) ingested by grazing animals.

forest land with a canopy cover greater than 30%.

fossil fuel – any hydrocarbon deposit that can be burned for heat or power, such as coal, oil and natural gas (produces carbon dioxide when burnt); fuels formed from once-living organisms that have become fossilized over geological time.

fossil water groundwater that has remained in an aquifer for thousands or millions of years; when geologic changes seal the aquifer preventing further replenishment, the water becomes trapped inside and is then referred to as fossil water. Fossil water is a limited resource and can only be used once.

freegan – a mortal using substitute strategies for living based on limited participation in the conventional economy and minimal consumption of resources. Freegans embrace community, generosity, social concern, freedom, cooperation, and sharing – in opposition to materialism, moral apathy, competition, conformity, and greed. The most notorious freegan strategy is “urban foraging” or “dumpster diving”. This technique involves rummaging through the nonsense of retailers, residences, offices, and other facilities for useful goods. The word freegan is compounded from “free” and “vegan”. cf. affluenza, froogle.

freon – DuPont’s trade study for its odourless, colorless, nonflammable, and noncorrosive chlorofluorocarbon and hydrochlorofluorocarbon refrigerants, which are used in air conditioning and refrigeration systems Fair trade – a guarantee that a clean price is paid to producers of goods or services; it includes a range of other social and environmental standards including country standards and the right to form unions.

freshwater – water containing no meaningful amounts of salt; potable water suitable for all normal uses cf. potable water.

front (weather) the boundary between warm (high pressure) and cold (low pressure) air masses.

froogle – a play on the word frugal, referring to people who lead low-consumption life-styles: a mortal who is part of a new movement towards self-sufficiency and waste-reduction reached by bartering goods and services particularly through the internet, making their own products, soap, clothes, and breeding chickens and goats, growing their own food, baking their own bread, harvesting their own water and energy, and helping to develop a sense of community. Sometimes referring to people who have prefabricated a resolution to only purchase essentials for a specific period of time cf. freegan, affluenza.

fugitive emissions – in the context of the National Greenhouse Gas Inventory, these are greenhouse gases emitted from fuel production itself including, processing, transmission, storage and distribution processes, and including emissions from oil and natural gas exploration, venting, and flaring, as well as the mining of black coal.

full-cost pricing – the pricing of commercial goodsuch as electric powerhat includes not only the private costs of inputs, but also the costs of the externalities required by their production and use cf. externality.

G

G8 – The Group of Eight is an international forum for the world’s major industrialised democracies that emerged following the 1973 oil crisis and subsequent global recession. It includes Canada, France, Germany, Italy, Japan, Russia, the UK and the US which represents about 65% of the world economy.

Gaia speculation – an ecological speculation that proposes that living and nonliving parts of the soil are a complex interacting system that can be thought of as a single organism.

gene pool – the total set of one-of-a-kind alleles in a species or population.

generalist species – those healthy to thrive in a wide variety of environmental conditions and can make use of a variety of different resources.

gene – a locatable region of genomic sequence, corresponding to a unit of inheritance, which is associated with regulatory regions, recorded regions and/or other functional sequence regions.

genetic diversity – one of the three levels of biodiversity that refers to the total number of genetic characteristics.

greenhouse effect – the process in which the emission of infrared irradiation by the region warms a planet’s surface.

greenhouse gas – components of the region that contribute to the greenhouse effect.

green manure – a type of cover crop grown primarily to add nutrients and biological matter to the soil.

Green Revolution – the ongoing transformation of agriculture that led in some places to meaningful increases in agricultural production between the 1940s and 1960s.

groundwater – water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formation.

garden organics – organics derived from garden sources e.g. prunings, grass clippings.

genetic engineering – general term covering the use of various experimental techniques to produce molecules of DNA containing new genes or novel combinations of genes, generally for insertion into a host cell for cloning; the technology of preparing recombinant DNA in vitro by slicing up DNA molecules and splicing together fragments from more than one organism; the modification of genetic fabric by man that would otherwise be subject to the forces of nature only.

genome the total genetic composition of an organism

geosphere – the solid part of planet Earth, the main divisions being the crust, mantle, and liquid core. The lithosphere is the part of the geosphere that consists of the crust and upper mantle.

geothermal energy – energy derived from the natural heat of the soil contained in hot rocks, hot water, hot brine or steam.

global acres see global hectares.

global dimming a reduction in the amount of direct solar irradiation reaching the surface of the soil due to light diffusion as a result of air pollution and increasing levels of cloud. A phenomenon of the final 3050 years.

economic globalization – the emerging international economy characterized by free trade in goods and services, unrestricted capital flows and more limited national powers to control domestic economies.

global hectares – acres/hectares that have been adjusted according to world average biomass productivity so that they can be compared meaningfully crossways regions; 1 global hectare is 1 hectare of biologically productive space with world average productivity.

global warming potential – a system of multipliers devised to enable warming effects of different gases to be compared.

global warming the observable increase in global temperatures considered mainly caused by the human induced enhanced greenhouse effect trapping the Sun heat in the Earth atmosphere.

globalisation the expansion of interactions to a global or worldwide scale; the increasing interdependence, integration and interaction among people and organisations from around the world. A general term, used since the mid 1940s, referring to a mix of economic, social, technological, cultural and political interrelationships.

glyphosate the active ingredient in the herbicide RoundupTM.

governance refers to the decision-making procedure – who makes decisions, how they are made, and with what information: the structures and processes for collective decision-making involving governmental and non-governmental actors.

green structure – building design that moves towards self-sufficiency sustainability by adopting circular metabolism.

green design – environmentally sustainable design.

green power – Electricity generated from clean, renewable energy sources (such as solar, wind, biomass and hydro power) and supplied through the grid.

green products and services – products or services that have a lesser or reduced effect on human health and the environment when compared with competing products or services that serve the same purpose. Green products or services might include, but are not limited to, those which contain recycled content, reduce waste, conserve energy or water, use less packaging, and reduce the amount of toxics disposed or consumed.

green purchasing – purchasing goods and services that minimise impacts on the environment and that are socially just.

Green Star a voluntary building rating for green design covering 9 affect categories up to 6 stars which equals world leader.

green waste (green biological fabric or green organics, sometimes referred to as reen wealth) – plant fabric discarded as non-putrescable waste – includess tree and shrub cuttings and prunings, grass clippings, leaves, natural (untreated) timber waste and weeds (noxious or otherwise).

green (sustainability) like co – a word frequently used to indicate consideration for the environment e.g. green plumbers, green purchasing etc., sometimes used as a noun e.g. the Greens.

greenhouse effect – the insulating effect of atmospheric greenhouse gases (e.g., water vapor, carbon dioxide, methane, etc.) that keeps the Earth’s temperature about 60 F (16 C) warmer than it would be otherwise cf. enhanced greenhouse effect .

greenhouse gases – any gas that contributes to the greenhouse effect; gaseous constituents of the atmosphere, both natural and from human activity, that absorb and re-emit infrared radiation. Water vapor (H2O) is the most abundant greenhouse gas. Greenhouse gases are a natural part of the region and include carbon dioxide (CO2), methane (CH4, uninterrupted 9-15 yrs with a greenhouse warming potential (GWP) 22 times that of CO2), nitrous oxide (N2O persists 120 years and has a GWP of 310), ozone (O3),hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride.

greenlash dramatic changes in the structure and dynamic activity of ecosystems.

greenwashing – a derogatory term used to describe companies that portray themselves as environmentally friendly when their commerce practices do not back this up. Generally applies to excessive use of green marketing and packaging when this does not take statement of the total ecological footprint.

greenwater water replenishing soil moisture, evaporating from soil, plant and other surfaces, and transpired by plants. In nature the global average amount of rainfall fitting green water is about 60%. Of the green water about 55% falls on forests, 25% on grasslands and about 20% on crops. We can increase green water productivity by rainwater harvesting, increased infiltration and runoff collection. Green water can't be piped or drunk (cannot be sold) and is therefore generally ignored by water management authorities but it is crucial to plants in both nature and agriculture and needs careful management as an important part of the global water cycle.

greywater household waste water that has not come into contact with toilet waste; includes water from baths, showers, bathrooms, washing machines, laundry and kitchen sinks.

gross primary productivity – total carbon assimilation.

groundwater water found below the surface generally in porous rocks, or soil, or in underground aquifers.

growth increase in size, weight, power etc.

H

habitat – an ecological or environmental area that is inhabited by a specific species.

hard waste – household nonsense which is not generally accepted into nonsense bins by local councils, e.g. old stoves, mattresses.

heat energy derived from the motion of molecules; a form of energy into which all other forms of energy might be degraded .

herbicide a chemical the kills or inhibits growth of a plant.

herbivory – predation in which an organism known as an herbivore, consumes principally autotrophs such as plants, algae and photosynthesizing bacteria.

heterotroph (chemoorganotrophy) – an organism that requires biological substrates to obtain its carbon for growth and development.

hierarchy an organisation of parts in which control from the top (generally with few parts), proceeds through a series of levels (ranks) to the bottom (generally of many parts) cf. heterarchy.

high density polyethylene (HDPE) – A member of the polyethylene family of plastics and is used to make products such as milk bottles, pipes and shopping bags. HDPE might be coloured or opaque.

homoclime a region with the same climate as the one under investigation.

horsepower (hp) = 745.7 watts.

homeostasis – the property of either an open system or a shut system, particularly a living organism, that regulates its internal environment so as to preserve a stable, fixed condition.

Horton overland flow – the tendency of water to flow horizontally crossways land surfaces when rainfall has exceeded infiltration capacity and depression storage capacity.

house energy rating – an assessment of the energy efficiency of residential home or unit designs using a 5 star scale.

household metabolism – the passage of food, energy, water, goods, and waste through the household unit in a similar way to the metabolic activity of an organism cf. industrial metabolism.

humus – biological fabric in soil lending it a bark brown or black colouration.

human equivalent (He) – the approximate human regular energy stipulation of 12,500 kJ or its approximate energy generating capacity at basal metabolic rate which is equivalent to about 80 watts (3.47222kWh/day). A 100 watt light bulb therefore runs at 1.25 He.

humus semi-persistent biological matter in the soil that can no longer be recognised as tissue.

hydrocarbons – chemicals prefabricated up of carbon and hydrogen that are found in raw materials such as petroleum, coal and natural gas, and derived products such as plastics.

hydroelectric power – the electrical power generated using the power of falling water.

hydrological cycle (water cycle) – the natural cycle of water from evaporation, transpiration in the atmosphere, condensation (rain and snow), and flows back to the ocean (e.g. rivers).

hydrosphere – all the Earth’s water; this would include water found in the sea, streams, lakes and other waterbodies, the soil, groundwater, and in the air.

I

incineration – combustion (by chemical oxidation) of waste fabric to treat or dispose of that waste material.

indicator species – any biological species that defines a trait or characteristic of the environment.

industrial agriculture – a form of contemporary farming that refers to the industrialized production of livestock, poultry, fish, and crops.

Industrial Revolution – a period in the late 18th and primeval 19th centuries when major changes in agriculture, manufacturing, and transportation had a profound effect on socioeconomic and cultural conditions.

infiltration movement of water below topsoil to the plant roots and below.

infiltration – the process by which water on the ground surface enters the soil.

indicators decimal markers for monitoring progress towards desired goals.

industrial ecology (term int. Harry Zvi Evan 1973) – the attending that nature produces no waste and therefore provides an example of sustainable waste management. Natural Capitalism espouses industrial ecology as one of its four pillars together with energy conservation, fabric conservation , and redefinition of commodity markets and product stewardship in terms of a service economy. Publications:

insecticide – a pesticide used to control insects in all developmental forms.

Integrated Pest Management (IPM) – a pest control strategy that uses an array of complementary methods: natural predators and parasites, pest-resistant varieties, cultural practices, biological controls, various physical techniques, and the strategic use of pesticides.

intercropping – the agricultural practice of cultivating two or more crops in the same space at the same time.

in-stream use – the use of freshwater where it occurs, generally within a river or stream: it includes hydroelectricity, recreation, tourism, scientific and cultural uses, ecosystem maintenance, and dilution of waste.

integrated pest management (IPM) pest management that attempts to minimise chemical use by using several pest control options in combination. The goal of IPM is not to eliminate all pests but to reduce pest populations to acceptable levels; an ecologically based pest control strategy that relies heavily on natural mortality factors and seeks out control tactics that disrupt these factors as tiny as possible.

integrated product life-cycle management – management of all phases of goods and services to be environmentally friendly and sustainable.

inter-generational fairness the intention to leave the world in the ideal doable condition for future generations.

Intergovernmental Panel on Climate Change (IPCC) – the IPCC was established in 1988 by the World Meteorological Organization and the UN Environment Programme to supply the scientific and technical foundation for the United Nations Framework Convention on Climate Change (UNFCCC), primarily through the publication of periodic assessment reports.

internal water footprint the water embodied in goods produced within a country (although these might be subsequently exported) cf. external water footprint.

intrinsic value the value of something that is independent of its utility.

irrigation index an efficiency indicator showing degree of match between applied and used water. Best rating = 1, an Ii of 1.5 means an oversupply of water by 50%.

irrigation scheduling watering plants according to their needs.

irrigation watering of plants, no matter what system is used.

ISO 14001- The international standard for companies seeking to certify their environmental management system. International Organisation for Strandardisation (ISO) 14001 standard was first published in 1996 specifying the stipulations for an environmental management system in organization (companies and institutions) with the goal of minimizing harmful effects on the environment and the goal of continual improvement of environmental performance.

J

joule (J) the basic unit of energy; the equivalent of 1 watt of power radiated or dissipated for 1 second. Natural gas consumption is generally measured in megajoules (MJ), where 1 MJ = 1, 000,000 J. On massive accounts it might be measured in gigajoules (GJ), where 1 GJ = 1 000,000,000 J.

K

kerbside collection – collection of household useful materials (separated or co-mingled) that are left at the kerbside for collection by local council services .

keystone species – a species that has a disproportionate effect on its environment relative to its abundance, affecting many other organisms in an ecosystem and help in determine the types and numbers of various others species in a community.

Kyoto Protocol – an international agreement adopted in December 1997 in Kyoto, Japan. The Protocol sets binding emission targets for developed countries that would reduce their emissions on average 5.2 percent below 1990 levels.

L

land use, Land-use change and forestry (LULUCF) – land uses and land-use changes can act either as sinks or as emission sources. It is estimated that approximately one-fifth of global emissions result from LULUCF activities. The Kyoto Protocol grants celebrations to get emissions credit for certain LULUCF activities that reduce net emissions.

landfill- solid waste disposal in which refuse is buried between layers of soil, a method often used to reclaim low-lying ground; the word is sometimes used as a noun to refer to the waste itself.

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GUNUNG BADAK, CIKEPUH-CITISUK, DAN CITIREM, KOMPLEKS PETROTEKTONIK JALUR SUBDUKSI KAPUR JAWA BARAT

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SARI
Kompleks Gunung Badak, Kompleks Cikepuh-Citisuk, dan Kompleks Citirem berada di
Teluk Ciletuh, merupakan lokasi dari kumpulan batuan Pra-Tersier. Daerah Teluk
Ciletuh berada di Kabupaten Sukabumi, Provinsi Jawa Barat. Batuan Pra-Tersier di
Ciletuh dikenal luas sebagai tektonik melange yang terbentuk dari penujaman lempeng
Indo-Australia terhadap Eurasia selama kala Kapur- Paleosen.
Ini merupakan studi menyeluruh dari kumpulan petrotektonik melalui perangkuman dan
analisis penelitian terdahulu (peta geologi dan studi laporan tidak terbit). Data diperoleh
melalui pemetaan geologi detil skala 1: 100.000, pengamatan lapangan, analisis
petrografi, analisis geokimia (dengan peralatan JEOL superprobe 733), analisis kimia
mineral dan pengukuran tekanan dan temperatur.
Kompleks Gunung Badak terdiri dari ofiolit (peridotit, gabro dan lava basal), batuan
metamorfik (serpentinit, kuarsit, filit, dan sekis), Kompleks Cikepuh-Citisuk disusun
batuan beku basa, ultrabasa, dan metamorfik sebagai lava basal, gabro, peridotit, dan
sekis, Kompleks Citirem disusun oleh lava basal (struktur bantal dan vesikuler).
Ke arah selatan (Gunung Badak menuju Citirem), kompleks ini disusun oleh kerak
samudera bagian atas; sebaliknya ke utara Kompleks Ciletuh disusun oleh kerak
samudera bagian dalam. Tersingkapnya batuan-batuan Pra-Tersier akibat adanya
pengurangan kecepatan penekukan pada masa Eosen-Oligosen Bawah, diimbangi
terbentuknya akresi, sehingga hadirnya kompleks melange yang mengandung blokblok
batuan ultramafik dan terdiri dari lempeng-lempeng serpentinit dan lava bantal. Di
saat bersamaan terjadi obduksi yang menyebabkan proses metamorfisme; pada kala
Oligosen Atas, adanya penambahan penekukan yang menyebabkan batuan metamorf
mengalami retrograde metamorfism, ditunjukkan dengan hadirnya mineral klorit yang
menggantikan aktinolit, albit dan kelompok epidot menggantikan plagioklas pada
batuan epidot amfibolit.
Kata kunci : Petrotektonik, Ciletuh, Melange, Penunjaman, Gunung Badak.

ABSTRACT
Gunung Badak, Cikepuh-Citusuk and Citirem Complex is situated in Ciletuh Bay. This
location consist of Pre-Tertiary rocks assemblages. Ciletuh Bay region located in
Sukabumi Regency, in West Java Province. The Pre-Tertiary rocks at Ciletuh have
been widely considered as tectonic mélange, which occured by subduction of Indo-
Australian and Eurasian plate during Cretaceous - Paleocene time.
This is a comprehensive study of petrotectonic assemblages by the results of
summary and analysis of previous research (geological map and unpublished reports).
Primary data are obtained from detailed geological mapping on 1: 100000 scale, field
observations and petrographic analysis, geochemical analysis (with JEOL superprobe
733), mineral chemical analysis, and temperature and stress measurement.
Gunung Badak Complex consists of ophiolite (peridotite, gabbro, and pillowed basalt),
metamorphic (serpentinite, quartzite, phyllite, and schist), and sedimentary rocks
(greywackes, nummulites limestone, black shale, red clay, and polymic breccias).
Cikepuh-Citisuk Complex consists of basic, ultrabasic and metamorphic rocks as
basaltic lava, gabbro, peridotite, and schist. Citirem Complex consists of thoelitic
basaltic lava (pillowed and vesiculars).
In southernward (Gunung Badak to Citirem), this complex consists of upper part
Oceanic Crust, inversely northward the Ciletuh Area consist inner part Oceanic Crust.
Uplifting of pre-Tertiary rocks is due to less of speed in underside Eosen-Oligosen
times, in balance by created of accretion, during the present of melange complex that
implied blocks of ultramafic rocks and consists of sepernitite plates basaltic lava. In the
same time obduction that made metamorphic process, at Upper Oligosen period, the
increase of subduction which cause metamorf rocks to go through metamorphism
retrogrades, showing by attended of klorite mineral that replaced aktinolit, albit and
epidot groups replaced amfibolit epidot rocks.
Keywords: Petrotectonic, Ciletuh, Melange, Subduction, Gunung Badak.

 

By

Yoal Dianto dan1 Yudih Saamena1
1Fakultas Teknik Geologi, Universitas Padjadjaran,
Jl. Raya Bandung Sumedang KM.21 Jatinangor 45363 Telp./Fax (022) 7796545.
Email : yoal.dianto@yahoo.co.uk, yudih.saamena@yahoo.com
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Error /problems in determining a palaeoenvironment

Error in determining a palaeoenvironment can be made due to the following factors:

1. Transport

This will cause a mixing of faunas from different environment

- Reworking of older sediments

- Contemporaneous transport

- As suspended load.The empty shells of dead foraminifera can be transported hundreds of miles offshore. Result:shallow water forms in deep water deposit

- By currents. This may be reflected in species or size sorted assemblages.

- By turbidity currents or slides.

- Vegetation. Attached living species may be transported over vast distances, when the vegetation is uprooted

- Wind. Empty shells of dead foraminifera may be blow land inwards

2. Bioturbation

The effect of bioturbation is rather minimal. Burrowing organisms may cause the mixing of different assemblages.

3. Diagenesis

Solution of calcareous test or the calcareous cement of arenaceous species can result in the complete absence of a fossil

4. Caving and contamination

Different preservation, colour or the degree of abrasion can be clue in determining transported or reworked faunas.

for more information please see foraminifera in http://regionalgeology.info

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Introduction geology

From Wikipedia, the free encyclopedia

Geology (from Greek: γη, gê, "earth"; and λόγος, logos, "speech" lit. to talk about the earth) is the science and study of the solid matter that constitutes the Earth. Encompassing such things as rocks, soil, and gemstones, geology studies the composition, structure, physical properties, history, and the processes that shape Earth's components. It is one of the Earth sciences. Geologists have established the age of the Earth at about 4.6 billion (4.6x109) years, and have determined that the Earth's lithosphere, which includes the crust, is fragmented into tectonic plates that move over a rheic upper mantle (asthenosphere) via processes that are collectively referred to as plate tectonics. Geologists help locate and manage the Earth's natural resources, such as petroleum and coal, as well as metals such as iron, copper, and uranium. Additional economic interests include gemstones and many minerals such as asbestos, perlite, mica, phosphates, zeolites, clay, pumice, quartz, and silica, as well as elements such as sulfur, chlorine, and helium. Geology is also of great importance in the applied fields of civil engineering, soil mechanics, hydrology, environmental engineering and geohazards.

Planetary geology (sometimes known as Astrogeology) refers to the application of geologic principles to other bodies of the solar system. Specialised terms such as selenology (studies of the moon), areology (of Mars), etc., are also in use. Colloquially, geology is most often used with another noun when indicating extra-Earth bodies (e.g. "the geology of Mars").

The word "geology" was first used by Jean-André Deluc in the year 1778 and introduced as a fixed term by Horace-Bénédict de Saussure in the year 1779. The science was not included in Encyclopædia Britannica's third edition completed in 1797, but had a lengthy entry in the fourth edition completed by 1809.An older meaning of the word was first used by Richard de Bury to distinguish between earthly and theological jurisprudence.

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FROM NON-ECONOMIC INTO PRODUCING FIELD, A CASE STUDY IN KETALING BARAT FIELD, INDONESIA

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

FROM NON-ECONOMIC INTO PRODUCING FIELD,
A CASE STUDY IN KETALING BARAT FIELD,
INDONESIA

Bob W.H. Adibrata(1), Y. Hirosiadi(2), E. Septama(3), A. Rachmanto(4)

1bobwikan@pertamina.com, 2yosihiro@pertamina.com, Geology Section, Technology Support Division,
Pertamina Upstream, Kwarnas Bld 15th Fl, Jl. Medan Merdeka Timur No. 6, Jakarta 10110 INDONESIA
3erlangga@pertamina-sumbagteng.com, Exploitation Section, Pertamina DOH Sumbagteng, Bajubang, Jambi
36611, INDONESIA
4ambar@pertamina-dohsbs.com, Recent address: Exploitation Section, Pertamina DOH Sumbagsel, Prabumulih,
Sumatera Selatan, INDONESIA

Abstract

Focus of this study is re-activity of a non-economic field into production by combining
old vintage 2D seismic data with current 3D seismic data, supporting with archival,
conventional log data and limited sidewall core and thin section analysis. The
reservoir consists of bioclastic wackestone overlying by coral bindstone in the Upper
Miocene Equivalent of Baturaja Formation, at Ketaling Barat field, Jambi, Indonesia.
The objective of this study is to evaluate and test a multiple attribute analysis
whereby carbonate facies can be determined and to characterize the distribution of
potential carbonate reservoir.

Introduction

Ketaling Barat field is located 5 km East of Jambi, Jambi Province, Indonesia (Figure
1). Activities in this field started in 1959 by Dutch’s NIAM N.V., by drilling 3 wells,
Ketaling 1, 2 and 3, which mainly based on geological field work in the surrounding
area. From those three wells, only Ketaling-2 gave respond with gross of 220 bbl fluid
per day (95% water). With the unsatisfactory result, this field was then abandoned as
a non-economic field for about 40 years. The first 2D seismic data acquisition taken
in 1982, and the vintage set was then re-processed in 2000 and re-interpretation was
held during the same year, with the result of Ketaling Barat (KTB)-04 that has been
drilled in 2001. The appraisal well of KTB-04 gave a significant result of 3600 BOPD,
with no water. Lithology variation between KTB-04 and previous wells, confer the
idea that there are two different stages in carbonate development in this area,
defined as Phase-1 and Phase-2. Phase-1 is platform carbonate where oil produced
from KTB-04, and Phase-2 is reefal carbonate, where oil from Ketaling-2 came from.
Four other wells has been drilled during 2001-2002 period, KTB-05 (Phase-1
reservoir, 1.5 MMSCF), KTB-06 (Phase-2 reservoir, 420 BOPD, 70 % water, 0.5
MMSCF), KTB-07 (Dry hole), KTB-08 (Phase-1 reservoir, Oil show, Technical
problem, P&A). Highly variation in result which represents reservoir heterogeneity,
lead to a mini pilot project (2 x 4 sq. km) of 3D seismic acquisition and processing
that was conducted in 2003 to enhance reservoir characterization.

Improved interpretation has achieved using 3D data volume. The Equivalent of
Baturaja Formation can be determined more clearly into two different stages. The two
stages, Phase-1 and Phase-2 has been mapped respectively. Phase-1 developed as
an isolated platform directly on top of basement, controlled by normal fault, spread out throughout the area with average thickness of 35 meter. Phase-2 developed as
reefal build-up facies, distributed mostly in the center of Ketaling Barat field, with
average thickness of 45 meter. Paleomorphology also worked as the main control on
carbonate development and distribution in the area.

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Dipmeter Surveys (Reef Interpretation )

Reef Interpretation

Introduction

Buried topography may significantly influence the thickness, sedimentation, and dip attitude of beds overlying topographic features. One of the first stratigraphic applications of dipmeter data was to determine the positions of wells drilled on buried topographic features. The factor contributing to the interpretation of these situations is the drape of beds over the underlying buried topography. Although this chapter deals primarily with reef interpretation, many of its basic principles apply to buried ridges, knobs, and depressions covered in the next chapter. The differences between them lie in the application of the interpretation.

The dip of reef surfaces is interpreted from the drape of sediments over the reef, particularly where the reef underwent considerable vertical growth. Dipmeter data obtained very near the reef or on the reef slope exhibit dip anomalies that help to describe the reef slope. The magnitude of the dip at any point above a reef varies depending on the following:

the slope of the reef surface

the height of the reef above the surrounding platform

the distance of the point above the reef surface

the type of rock above the reef

the total historical overburden

the position over the reef at which the measurements were taken (crest, flank, or toe)


Figure 1 shows the cross section of a barrier reef complex.

Dipmeter interpretation will be described for wells drilled

in pinnacle reefs overlain by shale

in pinnacle reefs overlain by low-compactibility formations

on the forereef slope

on the crest of the barrier complex


 

The dip patterns may be somewhat different in each of these cases because of the relief of the feature as well as the lithology of the enclosing formations.

Well-correlation and dip data have shown that the slopes on reef flanks can vary from 2° or 3° to as high as 45°. As evidenced by current reefs, higher slopes are possible, but are not generally observed in the subsurface. It is possible that erosion of steep and irregular slopes prior to burial produced reef flanks of reduced dip angle. Large accumulations of reef talus material near some reefs may support this premise.

Of the factors influencing the dip above a reef, the most important are reef topography and the compactibility of overlying beds. If all dip patterns above reefs conformed to the same model, interpretation would be straightforward. Unfortunately, identical dip patterns may imply quite different reef slopes in different environments.

Figure 2 is a photograph of a pinnacle reef in a Cambrian zone in West Texas. Some significant features show in the enclosing beds. Note the drape of the overlying beds in the flank position with the direction of dip sharply away from the reef mass.


 

It is useful to note that subsidence of the mass into the underlying platform has caused dip below the reef to be toward the reef mass itself.

Finally, within the reef there is generally a lack of distinct stratification.

Comments on Reef Interpretation

The tectonic and geological history of an area generally determines a maximum height of buried topography above a reference datum. This is particularly true of reefs, because the controlling conditions for vertical accumulation may prevail over a large portion of a basin.

Further, unfavorable conditions cause cessation of growth over large areas, and the limited vertical height becomes common to many reefs simultaneously. Therefore, a maximum expected height of reef crest above a datum may be well established.

Reef falls, or pinnacles that for whatever environmental reason ceased growth early, may have any thickness less than maximum. The length (and shape) of the slope pattern in wells drilled on the flank position may be interpreted qualitatively as a guide to the vertical size of the reef. "Typical" dipmeter patterns for the area are very useful in this respect.

The accuracy of interpretations discussed in this chapter depend largely upon knowledge of sediment compaction around reefs and other buried topography. The relatively simple procedures employed to estimate compaction may not apply directly to all areas.

Extrapolation of dip assuming a linear slope may be used best where experience with seismic and well-to-well correlations support this approach. Extrapolating updip beyond the elevation geologically possible or likely for a particular feature could be misleading and expensive. The basic concept should prevail, however, and persons employing these basics in their analyses are advised to consider all available data and experience.

Techniques

Reef Interpretation

The pattern of drape over a reef may be determined by a number of factors, including

  • compaction

compaction with deposition

solution of surrounding salts

solution with deposition of overlying sediments

gypsum to anhydrite conversion

combinations of the above

Compaction

In most circumstances, compaction plays the key role in causing drape over buried topography. It is useful therefore to refer to a model to understand and interpret the dip patterns.

The simplest model, and one with good independent support from well correlation, is illustrated in Figure 1 , which shows a simple reef mass of constant slope of 30° surrounded by shale.


 

If we know the compaction factor of the shale, and we assume that all shale compaction occurred after deposition and that the reef is rigid, then we can accurately calculate the present attitude of the shale bedding plane.

For this model it is assumed that present shale thickness is 50% of the original precompaction thickness; therefore, the resulting compaction factor is 0.5.

From these assumptions we can conclude that the dip of the shale bedding plane is the angle of the tangent, which is 50% of the tangent of the reef angle.

The equation is

tan-1(0.5 tan 30°) = shale dip = 16.1°

The general equation is

shale dip = tan-1 [(1 - C) tan reef dip]

where:

,

and

1 - C = compaction

Solving for the reef dip, which cannot be directly measured, we have

reef dip = tan-1 

reef dip = tan-1 

In this example, with a measured shale dip of 16.1°, we can calculate the reef dip to be 30°. Considering the range of local changes in compaction due to lithological changes, locally changing reef slope, or the fact that compaction may not be totally postdepositional, a simple solution is to divide the shale dip by an estimate of compaction.

reef dip =  = 32°

As shale-dip values increase, as in the case of very steep-sided reefs, the simplified solution becomes less accurate and the general equation should be used; however, slumping, fracturing, and sliding may render interpretation more difficult and the precision of reef slope less significant.

In the previous simplistic model where all compaction was assumed to occur after deposition, the theoretical dip pattern would be a constant 16.1°. Where beds are now essentially parallel, they may be considered to have been paralleled during deposition and therefore equally compacted. This model is applicable in these cases.

In general, however, the drape of beds over a reef produces a red pattern on the dipmeter plot if the well is drilled in the flank position. The existence of the red dip patterns implies that compaction cannot be assumed to be postdepositional except over limited intervals where the dip magnitude is relatively constant. In this case, the compaction may only be invisible over short intervals because of the low rate of change of dip with depth. Provided other factors remain constant, reefs with large relief tend to produce long red patterns above; those with low relief produce shorter patterns. In any case, it is the analysis of the red pattern that allows us to calculate the reef slope.

Estimating Height of Nearby Reefs

Two basic dip patterns have been observed in shale-enclosed reefs. The first is a long, slowly increasing red pattern. The dip of the shale above the reef is some fraction of the reef dip, and the reef dip is estimated using the earlier derived equation. The interval from 1315 to 1365 m shows little dip change, which indicates that it was deposited prior to most of the compaction process. This zone is therefore a candidate for the simple model approach.

The second dip pattern observed in shale-enclosed reefs is characteristic of steep-sided, probably curved surfaces of high-relief pinnacles ( Figure 2 ).


 

Statistically, this pattern has two sections. The lower section is characterized by a sharp slope pattern immediately above the reef. The upper section is a long and slowly decreasing slope pattern. Where the sharp slope pattern and the slowly decreasing dip pattern join is the approximate height of the nearby reef.

Estimating the Reef Slope

The reef slope should be estimated using two methods. First, applying your knowledge of compaction to the upper dip section, calculate the dip. Second, extrapolate the lower red dip pattern to the reef surface. This dip is a good estimate of the reef dip at the contact, but it may not persist over long horizontal distances. If the two dips agree within a few degrees, confidence in the answer is high. If the two dips do not agree within a few degrees, they at least establish a range of possible dip. Knowledge of the seismically defined size and shape should be integrated into the final solution.

Where overlying beds are of low compaction, the overlying dip also is less. For example, a formation with compaction of 20% and a dip over the reef of 4° would imply a reef dip of approximately 20°. In this case the red pattern would not be nearly as striking as in the previous examples.

Some interpreters may be tempted to find the exact depth of the contact, and they may seek a particular tadpole to define the dip of the surface. This approach can give quite erroneous results, because of the local irregularities existing on any weathered surface. These irregularities may be of a size on the order of the borehole diameter.

In this case the dip at the contact would be entirely misleading, and the general dip trend is better defined from dips sufficiently above the surface, because the small features would have been compensated by sedimentation and compaction.

As a general rule, dip patterns should be extrapolated horizontally in the same order as the vertical length of the pattern. This implies that any single-dip tadpole should not be extrapolated beyond the borehole.

Reef Detrital Material

Dip within a reef is not generally very well ordered. There is one exception, however: reef detrital material.

Reef detrital material is often found in accumulations near the base of the reef, and dip patterns within this material may have the appearance of foreset bedding.

This bedding may have dips greater than the reef dip, but the direction should be generally downslope. This information is particularly useful where it supports draping dip in overlying beds and in situations of low reef dip or low compaction.

The only indication of this detrital material may be from the dip-meter plot, as there is little mineralogical distinction between detritus and the main reef mass. This information may be significant when estimating the depth of the reef top, particularly where the detrital section is quite thin.

Reefs Surrounded by Salt

Reefs surrounded by salt are not likely to exhibit strong dips in the overlying sediments. If salt solution occurs simultaneously with or subsequent to deposition of these sediments, a dip pattern is produced. This pattern is determined by the rate and timing of the removal of salt. If salt removal commenced after deposition of some of the overlying beds, then these beds would have collapsed to more or less conform to the reef surface. Their dip would then be equal to the reef dip, and a pattern of essentially constant magnitude would be formed. This is illustrated in interval A in Figure 3 .


 

If the beds of interval B were being deposited during the removal of salt, a red pattern over that interval would be produced on the dipmeter plot. Interval B could be expected to thicken in the downdip direction.

The dip pattern in the figure would be further modified by compaction during and after deposition, but the basic pattern would be recognizable. Reef dip in this case would be approximately equal to or slightly greater than the constant dip value of interval A.

If salt removal occurred contemporaneous with the deposition of some of the overlying beds, most of the interval above the reef would exhibit a red pattern, as illustrated in Figure 4 . The dip of the reef would approximately equal the trend of the red pattern extrapolated to the reef contact. Extrapolation of red patterns of drape over reef or weathered surfaces is necessary, because dips near the surfaces may be difficult to ascertain due to bedding destruction by fractures, slump, or sliding and local irregularities of the surface.


 

Dipmeter Interpretation

Figure 5 illustrates the dipmeter pattern of a well drilled in the flank position of a reef where salt removal around the reef played a significant role in the final dips of the overlying beds. The pattern may be analyzed as follows:


 


 

Interval A contains a section of relatively constant dip with an average value of 15° to 18° east. This interval was probably deposited prior to salt removal, and it represents the minimum dip of the reef.

Interval B contains a red pattern that indicates the period of salt removal.

Interval C contains a long, gentle red pattern that finally disappears well above the top of the figure. This pattern is probably a reflection of compaction during deposition, and it would be superimposed on the patterns of intervals A and B.

Because regional dip in this area is less than 1° to the southwest, the consistent east dip above 3900 ft is interpreted as part of the overall drape on the reef. The long drape feature, over 1000 ft in length, suggests that the reef feature is not small.

Based on the seismic interpretation and the dip data, it was decided to whipstock the well to contact the reef 300 ft to the west. The result was to gain 90 ft of elevation on the reef. A straightline correlation between the two contacts implies a reef dip of 16-1/2°, approximately the mean value of the tadpoles in interval A.

Exercise 1.

Figure 1 shows a Devonian reef which has a long, linear slope in this area. Regional dip is 1° SW.

Compaction is 40 to 50%.

What is the reef dip?

What is the direction of dip?

How far and in what direction must an offset be drilled to gain maximum reef?


 

Solution 1:

The long red dip pattern terminates at 6° just above the reef talus interval and would extrapolate to the reef surface at about that angle.

If compaction = 50%,

reef dip 

If compaction = 40%,

reef dip 

Direction of dip = NE.

Additional reef available is 190 ft.

If dip = 12°, go 890 ft.

If dip = 15°, go 710 ft.

Calculated from offset = 

As shown in the accompanying figure, the actual offset well gained 160 ft in 700 ft offset from a reef dip of 13°. Compaction of the shale calculates to be 40% from the data in these wells.


 

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Dipmeter Surveys (Fault Interpretation)

Fault Interpretation

Introduction

Faulting occurs when beds are in tension or under compression. Such forces produce normal faults and reverse or thrust faults. In areas that have undergone mainly tension (such as the northern Gulf of Mexico), almost all of the faulting is normal. In areas that have undergone both earlier tension and later compression, both normal and reverse/thrust faults may be present in the same well. For dipmeter interpretation, input of the local geology is required to define the actual model.

In order for a fault to be detected by the dipmeter, either some sort of distortion must be present near the fault plane or one fault block must be tilted more than the other. When tilting is present, the location of the fault is indicated by a sudden change in dip magnitude and/or direction.

Typical forms of distortion near both tensional and compressional faults are shown in Figure 1 . Each of these is covered in this section. Normal faulting (beds in tension) is discussed first and reverse/thrust faulting (beds under compression) last.


 

Growth Faults

Faults that were active during the time of deposition are called growth faults. The downward-moving block provided a low area that acted as a sediment sink and accumulated thicker layers of sediments than the equivalent upthrown zone. Tension-created slumping into the downthrown side of the fault also aided the downthrown thickening processes. Downthrown thickening, which begins some distance from the fault, increases toward the fault plane, with the maximum amount of thickening found immediately downthrown. This thickening into the fault, plus sinking of the increasingly heavier downthrown side of the fault, produces a rotation effect that also increases the dip of the beds into the fault.

Rollover

The cumulative effect of downthrown thickening, slumping, and rotation, which is called rollover, produces a trend of downward-increasing dips that dip toward the upthrown fault block ( Figure 1 ). This trend terminates at, or shallower than, the fault plane. It is this dip trend that allows growth faults to be located, and their attributes identified, by the dip-meter tool. The downward-increasing dip trend produces a red dip pattern whose azimuth is toward the upthrown fault block and normal to the strike of the fault. Although not routinely found associated with growth faults, strike slip rotates the azimuth in a opposite to that of block movement. The vertical extent of the red pattern can be used as an indicator of the minimum displacement of the fault. Displacement is usually greater than the vertical extent of the fault; it is rarely less.


 

Subsidence Effect

When the rate of deposition is greater than the rate of subsidence, a system of progressively younger faults in a seaward direction is created. When the rate of deposition equals the rate of subsidence, a fault with a very large displacement is produced, assuming of course that the system is stable for a considerable period of time. When the rate of deposition is less than the rate of subsidence, progressively younger faults are created in a landward direction.

Bed Thickness

Figure 2 is a cross section illustrating the effect of a growth fault on bed thickness. Wells 1-3 penetrated the upthrown block of a down-to-the-east growth fault. Both sands A and B are the same thickness in both wells. Part of sand A is faulted out in Well 4, while sand B, which is still located upthrown, remains the same thickness. Well 5 penetrated sand A in a downthrown position in the rollover zone, so the sand is much thicker than its upthrown equivalent. Sand B was faulted out of Well 5. Well 6 penetrated both sands in a downthrown position within the rollover zone, so they are thicker than their upthrown equivalents. The downthrown thickening continues to decrease to the east until Well 9 is reached. This well is located beyond the eastern limit of the rollover zone, so both sands are the same thickness as their upthrown equivalents.


 

Growth Fault Examples

Figure 3 is an example of a large growth fault which cuts the Vicksburg formation of a South Texas well. The fault, which cuts the well at a depth of 14,890 ft, is downthrown, or dips, to the southwest. Therefore the rollover zone, which dips toward the upthrown block, dips to the northeast. The rollover zone (the zone that creates a downward-increasing dip trend) extends upward to 13,750 ft; the minimum displacement of the fault is approximately 1000 ft.


 

Figure 4 is an example of an offshore Louisiana fault whose displacement is smaller than that of the fault in Figure 3 . This offshore Louisiana Miocene example illustrates the rollover created by a small growth fault. The fault, which by correlation has a displacement of only 120 ft, is located at 12,638 ft and is downthrown, or dips, to the south-southeast and strikes normal to the pattern dip direction, or east-northeast west-southwest. Because of shattering of sediments near the fault plane, only a scattering of dips were recorded immediately downthrown.


 

Some fault examples show even more extensive shattering and washing out of the hole on the downthrown (most active) side of the fault plane. The dip trend which begins at the base of the blank zone is recorded from the upthrown block, so the fault cut is no deeper than the bottom of the blank zone. Usually it is picked at the base of the blank zone.

One of the "eyeball" indicators of a possible missing section, which is present in these examples, is a borehole dogleg. Any time the bit crosses a formation compaction change it reacts by creating a change in the amount and/or direction of well drift. Since compaction changes are almost always present across a fault or unconformity, a change in well drift azimuth and/or magnitude can (but does not always) indicate the presence of a fault or unconformity.

As long as a fault continues to grow, downthrown thickening is produced. This in turn produces an increasing-with-depth red dip pattern. During periods of relative nongrowth resulting from changes in depositional processes, the beds are rotated at a constant rate. This in turn produces constant dip zones within rollover-created red dip patterns. Figure 5 is an example of such a fault. The increasing-with-depth rollover zone begins at about 8700 ft. From 9100 to 9250 ft the dip trend remains constant. From 9250 down to 9350 ft the dip again increases downward, indicating a period of renewed growth.

Structural Dip Imprint

The dips from a zone of distortion are changed when structural dip is imprinted on them, so it may be necessary to remove structural dip before determining the attributes of a fault, just as it is necessary when making stratigraphic interpretations.

Figure 6 is a theoretical example of the appearance of a dip-meter plot when structural dip is imprinted over dips created by rollover. (A) shows a west-dipping red dip pattern created by rollover into a down-to-the-east growth fault. (B) shows that a moderate amount of east structural dip was added to the west dipping red pattern of (A). The resultant dip pattern, moving down the hole, is a decreasing dip trend or blue pattern. The dip decreases to zero, then increases in the opposite direction until a maximum is reached at the fault. A typical red pattern is formed below the zero crossing point. Below the fault cut, only east structural dip is seen.

(C) illustrates an even stronger east structural dip imprinted over the west-dipping red pattern. At the point where the west-dipping structural dip and the strong east structural dip start to oppose each other, a decreasing dip trend, or blue pattern, begins. In this case, the trend decreases down to the fault cut but never quite reaches zero dip. As soon as the fault is crossed, only strong east structural dip is recorded.


 

Figure 7 is a dipmeter example of the first type of imprint, where a strong red pattern opposes moderate or low structural dip in the opposite direction. Structural dip is about 10° south-southeast. This opposes the northwesterly dipping red pattern dipping into a down-to-the-southeast growth fault. The resulting dip patterns are ones of decreasing dips (blue pattern) from 13,700 ft down to the zero crossing point at 13,790 ft, then ones of increasing dips (red pattern) in the opposite direction down to the fault cut at the base of the blank zone at 13,880 ft.


 

Deviated Wells

Deviated wells are sometimes drilled parallel to fault planes. As a well periodically gets closer to the fault and, in some instances actually bumps the fault, the dips increase and then decrease. Some dip scatter is created by formation shattering and hole conditions near the fault.

Platform wells may be deviated in a direction and an angle such that they cross normal faults from the upthrown to the downthrown sides instead of in the usual manner.

Postdepositional Precompacted Faults (No Distortion)

Normal faults that occur after deposition but before formation compaction usually exhibit no distortion near the fault plane. Such faults can be recognized on the dipmeter plot only if a change in structural dip occurs across the fault. Because there is a change in the degree of formation compaction, the borehole doglegs even though there is no distortion of the beds near such a fault.

The sudden downward decrease of structural dip is one of the "eyeball" indicators used to differentiate between faults and unconformities. Most of the time, in areas that have not undergone strong tectonic deformation, the downward decrease indicates faulting. In order to have lower dip below an unconformity, two different centers of uplift are required.

Instead of downthrown rotation, some faulted areas have undergone rotation of the upthrown fault block. This creates a sudden structural dip increase in a downward direction. This is the same dip pattern created by the presence of an angular unconformity or a rapid, postdepositional structural uplift. Therefore, other information is needed to determine which of the three features is present when a sudden downward increase in structural dip is noted on the dipmeter plot.

A lack of distortion near a fault plane can occur with both tensional and compressional faults. Therefore, unless there is a structural dip change at the fault cut, faults of this class cannot be seen on dipmeter plots.

Postcompaction Faulting (Drag)

Normal faulting that takes place after some degree of deformation has occurred usually develops drag, or beds dipping in the same direction as the fault, near the fault plane. In some areas, drag is found only on the downthrown side of the fault; in others, drag may be found in beds on both the downthrown and upthrown sides.

Since the relative motion of the upthrown and downthrown fault blocks creates a drag zone whose dip is in the same direction as that of the fault plane, the maximum dip of the resulting red dip pattern may be used as a minimum dip of the fault plane. Local experience is used to determine whether or not the maximum dip of a drag-generated red pattern is in fact a reasonable value for the dip of a fault plane. Figure 1 is a theoretical example of a normal fault with drag only on the downthrown side. The red pattern, which was generated by the downthrown drag zone, dips in the same direction as the fault and normal to the strike of the fault. The maximum dip of the pattern may be used as the minimum dip of the fault plane. As happens with a growth fault, the hole doglegs within a hundred feet or so of the depth at which the fault cuts the well. Since drag is present only on the downthrown side, structural dip is recorded on the upthrown side of the fault.


 

Figure 2 illustrates a normal fault with drag in both the upthrown and downthrown beds adjacent to the fault plane. The dip in the downthrown block created a dip pattern similar to the one in the previous example. However, drag, which is also present in the upthrown beds, creates a pattern of downward decreasing dips or a blue pattern. The fault cuts the well at the junction of the two patterns. Once again, the maximum dip of the red pattern may be used as a minimum dip of the fault plane.

The amount of rollover present on the downthrown side of a nonburied growth fault decreases upward. It disappears at a point corresponding to the time at which the fault ceased to be active. The amount of drag created by any period of movement remains relatively constant over the entire interval. The termination point may be a point corresponding to the end of the active faulting period, or, if buried, to an unconformity.

Faults with Hybrid Dip Patterns near the Fault Plane

Some faults begin as growth faults with downthrown rollover zones. Either continued movement along the fault plane or movement that began after compaction occurred then created a downthrown drag zone. Since rollover and drag-generated dips oppose each other, dip patterns like those illustrated in Figure 1 are created by continuing or later fault movement. A red, or downward-increasing, dip pattern begins at the point at which the hole penetrated the rollover zone. The dips increase down to the point at which the drag-zone dips begin to oppose the rollover dips. The trend then decreases downward to the zero crossing point. Below that point, another red pattern dipping in the same direction is formed. The dips continue to increase in magnitude down to the fault cut. On the upthrown side of the fault the dips may return immediately to a structural trend, or indicate an upthrown drag zone.


 

Buried Faults

Growth faults die out gradually in an upward direction. Postdepositional faults may extend to the surface, where they create cliff-like scarps, or they may end abruptly at an erosional surface. Such faults are called buried faults.

In addition to ending abruptly at an unconformity, disconformity, or diastem, buried faults may change displacement across deeper unconformities. The buried-fault creation process is illustrated in Figure 1 . First, a fault extending to the surface is formed. Later, erosion removes the elevated portion of the upthrown block; the land surface is once again level across the fault zone.


 

The original amount of uplift is labeled a. Still later, deposition begins again, and horizontal sediment layers are deposited above the erosional surface. Subsequently, movement again occurs along the fault plane. This movement creates a displacement labeled b. The displacement of the beds below the unconformity is now a + b.

Erosion has removed the beds that were originally displaced by amount a. Therefore, only displacement b extends across the unconformity on the upthrown side. If erosion occurs again, the beds that were uplifted above the surrounding land surface will be eroded to a flat surface.

The displacement below the shallowest unconformity is equal to b. The displacement below the deepest or oldest unconformity equals a + b. This cycle may be repeated.

Figure 2 illustrates a buried fault example from eastern Venezuela. A down-to-the northwest growth fault is located at 3842 ft. The fault terminates at a depth of 3760 ft, which is the unconformity separating the Paleozoic from the Lower Cretaceous.


 

This growth fault was originally active in Paleozoic time. Any scarp that existed was eroded before Lower Cretaceous sediments were deposited above the unconformity. No subsequent movement occurred along the fault plane.

Since both types of distortion (rollover and drag) commonly found near normal faults create similar dip patterns, some local knowledge is useful in determining which type to use when making an interpretation. In any given area one type of distortion is found near most of the area faults. For example, in the northern Gulf of Mexico and in Nigeria, rollover is the dominant distortion type. In Mississippi and North Louisiana, drag is most often found on the downthrown side of normal faults.

Here are some rules of thumb for determining the type of distortion present near a normal fault:

If the vertical extent of the downthrown mega-red dip pattern is more than 200 ft, rollover is assumed. Normal fault drag rarely extends vertically more than 200 ft.

When the vertical extent of the mega-red dip pattern is less than 50 ft, drag is assumed. In areas where rollover dominates, this assumption can lead to incorrect interpretation about 30% of the time, since many small growth faults do exist. When the vertical extent of the mega-red pattern is between 50 and 200 ft, use the dominant type of distortion known to exist in the area.

Deviated wells may cause the extent of the dip pattern to be expanded by 50% or more. Hole deviation must be taken into account when using the vertical extent of a mega-red pattern as input into one of the rules of thumb.

Semicontemporaneous antithetic fault systems that help accommodate rotation are often found associated with growth fault systems. These faults usually exhibit downthrown drag that creates red dip patterns dipping toward their downthrown blocks. The dipmeter example in Figure 3 shows three such faults. These faults are down-to-the-northwest so the northwest dipping red dip patterns found on their downthrown sides are the result of drag rather than rollover. These antithetic faults are dipping into a large down-to-the-southeast growth fault which is below the total depth of this well.


 

Compressional Faults

Faults that result from compressional forces may, depending on the fault angle, be called reverse or thrust faults. The fault angle of reverse faulting is 45° or more, while thrust fault angles are less than 45°

The main form of distortion found near a reverse or thrust fault is drag on both sides of the fault. Drag, which is the result of movement of compacted beds, may be additionally modified by horizontal movement, or strike slip.

The compressional fault attributes that may be available from dip-meter plots are depth, strike, direction of overthrust, and fault angle. Figure 1 illustrates the expected dip patterns near compressional faults. Such faults commonly show up very well on dipmeter plots. A mega-red dip pattern is usually found in the overthrust block. Its azimuth is in the direction of overthrust, assuming, of course, that no strike-slip has occurred. The downthrown pattern is one of downward-decreasing dips, or a blue pattern. These dips also point in the direction of overthrust. Both dip patterns are the result of drag on both sides of the fault. The fault is located at the junction of the red and blue patterns.

Figure 2 is a dipmeter example from western Venezuela showing a reverse fault. Structural dip above 7800 ft is 12° southeast. From 7800 to 8450 ft westerly dipping beds in the overthrust drag zone oppose the southeast structural dip. This produces a decreasing-with-depth pattern down to the zero crossing point at 8030 ft; the pattern then increases downward to the fault cut. The dip azimuth reverses across the zero crossing point.


 

The maximum dip of this example is recorded at the fault. The blue pattern generated by the downthrown drag zone decreases rapidly. The dip patterns near major compressional faults are rarely symmetrical. The overthrust pattern usually has the greatest vertical extent. If the displacement is small (i.e., less than 100 ft), the red and blue dip patterns tend to be more nearly symmetrical.

The dip direction on both sides of the fault is the same as the direction of overthrust, which is to the west in this example. The strike of the fault, north-south, is normal to the direction of dip patterns.

In this example, the direction of structural dip in the overthrust block and the direction of overthrust are opposite, so the dip trend decreases to the zero crossing point and then increases in the opposite direction. Had the direction of structural dip and of overthrust been the same, the dip trend would have continued to increase in the overthrust drag zone. Horizontal movement of one block relative to the other (strike-slip) may also occur. The drag-created dip patterns, which dip in the direction of over-thrust, would be modified by any horizontal movement. When such movement occurs, the drag dip patterns are rotated in the trailing direction, which is opposite to the direction of movement, and so no longer indicate the direction of overthrust.

Both compressional faults and overturned folds create repeat sections on logs. If the repeat is right side up, it is the result of faulting. If one repeat is upside down or a mirror-image of the other, it is the result of folding.

Thrust Fault

UNDER CONSTRUCTION … !

Exercise 1.

See Figure 1 .


 

There is a missing section in this well between 14,000 and 14,100 ft.

Where is the dip change that indicates the location of the fault?

Where is the top of the rollover zone or top of the mega-red dip pattern?

What indicator suggests the presence of rollover rather than drag?

What is the minimum displacement of this growth fault?

In what direction is the fault downthrown?

What is the strike?

Is a dogleg present?

Solution 1:

The dip change corresponding to the base of the rollover zone is at 14,049 ft.

The top of the mega-red dip pattern, which corresponds to the top of the rollover zone, is at 13,680 ft.

The vertical extent of the red pattern is more than 200 ft; therefore, rollover rather than drag is present.

The minimum displacement of the fault, which is equal to the extent of the red pattern, is 370 ft.

The rollover zone dips into the fault; therefore, the fault is downthrown to the south and strike is EW.

There is a dogleg. The hole is vertical at 13,000 ft and drifts to the SE a maximum of 3-1/2° at 14,000 ft. The hole then begins to straighten.


 

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