Selection of Services and Equipment

Selection of Mud-Logging Services and Equipment

When an exploration or production well is to be drilled, it is standard planning procedure to use the economics of the drilling program to select the different services and/or "stand-alone" equipment, or both, to be used. As with most wellsite services and leased equipment, the anticipated costs of mud logging are balanced against resulting benefits.

Exploration and production departments make estimates of cost-per-interval drilled (e.g., cost per meter) and balance the effect of one cost factor against another, using a general formula such as:

where:

C = cost per interval drilled, ($/m or $/ft)

B = bit and other relatively fixed well costs, ($)

R = rig and services costs, ($/hr)

T = time spent drilling, (hrs)

t = time spent not drilling, (hrs)

H = interval drilled, (m or ft)

Mud-logging and leasing costs are included in rig-operating costs (R). Addition of any mud-logging service and leased equipment increases this cost and hence the cost per each interval drilled (C) of the well.

Obviously, to be cost-effective, the addition of any service must reduce other costs so that interval cost (C) is returned to its original or a lower figure. This can be done by decreasing the total "fixed" cost of products and tools used during the drilling life of the well (B) (e.g., reducing the amount of mud additivies used or the number of bits required to reach total depth). Alternatively, expenditures can be lowered by reducing other operating costs (R) (e.g., decreasing the number of wireline logs, DSTs, or outside safety services needed). Savings can also be made by reducing overall drilling and nondrilling time (T and t) or by maintaining all costs and times while increasing the interval of hole drilled (H) per unit of time.

While all of these types of savings are possible if mud-logging data are gathered and acted upon in a timely fashion, the most effective means of reducing expenditures through mud-logging functions is to reduce rig time (T and t).

Most day-to-day reductions in rig time using mud-logging data are through the maintenance of proper mud overbalance and optimum drilling practices, which includes determining the most efficient weight on bit, rotary speed, and bit-replacement schedule. In addition, large amounts of rig time can be saved if any potential drilling stoppage, such as hole instability, geopressure, acidic gases, or a kick, is recognized early enough to respond to remedial treatment while drilling continues.

Mud-Logging Programs

Mud-logging services vary from simple combustible gas analysis to complex down hole measurements made while drilling. The most basic capabilities are represented by contractors using units that are essentially identical to mud-logging units introduced in the 1940s and 1950s. These may still be adequate for low-risk production wells. At its highest level, mud logging can incorporate technology as sophisticated as any other equipment regularly operated at the well-site. Such highly automated and computerized services generally find use on expensive, deep, high-risk wells or on multiwell platforms.

Conventional Mud Logging

The basic level of mud-logging services provided by large companies is generally classified as formation logging. The formation-logging unit should have the equipment necessary to make full visual examination of cuttings and shows, and provide total hydrocarbon detectors for both mud stream and cuttings samples, as well as a gas chromatograph/flame ionization detector for determining individual hydrocarbon gases. To assist in plotting and interpreting cuttings and gas analyses, the unit should have a total depth recorder, a pump stroke counter, and drafting and reproduction capabilities.

With this minimal configuration, a single technician may be responsible for around-the-c lock operation. If this is the case, the wellsite geologist or engineer will have to perform or arrange for some sample collection, description, and monitoring functions. At the single-operator level, only passive geopressure recognition should be anticipated and no rapid response capabilities should be expected.

Preferably, two qualified technicians will share responsibility for operation of the mud-logging unit at the formation-logging level. In this situation, each technician generally takes a daily twelve-hour shift. Many logging companies use a fourteen-day-on/seven-day-off rotation so that three individuals may be involved in a two-man crew during the drilling life of a well. A very practical consideration is that these logging personnel be familiar with local geology and experienced in drilling practices of the area.

At the two-operator level, continuous, up-to-the-hour plots of basic geopressure parameters, such as shale density and connection gas, should be available at the wellsite.

When comprehensive pressure, geochemical, and nonhydrocarbon gas evaluative programs are to be provided as part of formation logging, a third, on-site technician probably will be required. In addition, some computer capabilities and supplemental mud monitoring and analytical equipment will be needed.

Advanced Mud Logging

Many modern mud-logging units provide additional sensors or services beyond those of the conventional, formation-logging level. The most advanced units provide advanced mud gas, geopressure, and petrophysical evaluations, plus drilling-data monitoring, acquisition, and interpretation. An analytical or interpretive specialist probably will be needed to carry out functions required by these programs. This technician may serve as the third on-site logger in the unit or be a fourth member of the crew.

When MWD systems are added, costs increase to cover equipment required to handle receipt of downhole data. In addition, leasing costs of down hole tools must be added to the drilling cost analysis. In general, two mud-logging crew members will have to be drilling specialists.

 

Stand-alone Equipment

Stand-alone instruments, displays, and apparatus that duplicate those of many mud-logging services and units generally are of two types: equipment that measures one specific wellsite condition( Figure 1 , Examples of basic stand-alone equipment for monitoring routine drilling variables) and equipment that monitors one rig system or more (e.g., driller's console) ( Figure 2 , Examples of multiple-function stand-alone equipment for monitoring and evaluating drilling operations). The following are examples of stand-alone equipment generally available for performing independent mud-logging functions.

 

· Basic Equipment:

Total hydrocarbon gas analyzer

Carbon dioxide monitor

Hydrogen sulfide monitor

Revolutions/minute and strokes/minute counters (rotary table, pumps, etc.)

Mechanical, pneumatic, and hydraulic multichannel recorders

Trip tank monitor

Mud volume totalizer

Mud flow/fill indicator

Mud density/temperature sensors

 

· Systems Equipment:

Mud system monitor (mud pump strokes, mud pump pressure, total mud volume, trip tank volume, total fill strokes, return mud flow, mud volume deviation)

Drilling controls monitor (equipment in mud system monitor plus weight on bit, total hook load, rotary speed, rotary torque)

Rig data processor (the equipment already mentioned, plus instruments and computer to provide standpipe and annulus pressure, accumulated fill, ROP, mud temperature in/out, drill depth, d-exponent, stands in hole, total trip time, total drill time, total system time)

 

Contracts and Leases

Selection of specific mud-logging services or equipment for a pending well starts at the time authorization-for-expenditure (AFE) procedures begin. In most drilling situations, the geologist defines the mud-logging or stand-alone program to be used at the wellsite. This program will be, in part, based on a cost-effectiveness formula.

When a mud-logging contractor is to be used, the program outlined by the geologist will include such items as the level of mud logging and log preparation to be carried out, the number of personnel to be provided by the contractor, and rigup and rigdown conditions. The latter should specify at what depth mud logging is to be fully operational and at what point, such as after final wireline log runs, the mud-logging unit and crew can move off. It also is advisable to include in the program a well-end debriefing requirement at which wellsite logging personnel review and summarize the various mud-logging plots and logs for the geologist and engineer.

When stand-alone equipment is to be used, the list of equipment and specifications is prepared together with an outline of the operator's personnel who will be responsible for equipment use.

The conditions to be met by the mud-logging contractor or stand-alone supplier are given to the engineer preparing the drilling specifications of the AFE. The engineer, in turn, provides these specifications to potential contractors and suppliers for bids or quotations. When the outside service companies have responded to the operator, their bids or quotations are reviewed by the engineer and geologist to determine how adequately they meet the specifications and anticipated costs of the drilling program. In the case of stand-alone equipment, the supplier probably will have made a visit to the drill rig prior to responding in order to determine the nature of instrumentation already at hand and to assure that all leased equipment will be compatible with rig systems.

After a final mud-logging or stand-alone program and its service company have been selected, a contract or lease agreement is drawn up between the participants specifying details of work and/or equipment to be provided. This is reviewed by the geologist and engineer.

At the time that all outside service contracts and agreements have been made (e.g., mud logging, mud engineering, bit supply, wireline logging), the operator holds a prespud meeting with contractors and suppliers to review the total drilling program. At this meeting, or more commonly at a subsequent prespud meeting in which only interested parties are involved (i.e., geologist, engineer, mud log contractor), any unclear conditions concerning mud-logging requirements or stand-alone configurations are answered. In particular, if a new mud-logging service company or setup is being used, this prespud meeting is the time to reaffirm such stipulations as log scales, sample interval, sample type(s), reporting frequency, reporting chain, shipping procedures, tight-hole procedures, and lag requirements.

When a mud-logging service is to be used, the first meeting between the geologist, engineer, and full mud-logging crew probably will occur when the mud-logging unit is moved on the site or platform. This generally is a day or two prior to reaching the specified depth at which full logging is to start. Prior to this point in the drilling program, all contractual obligations should be clear to both the operator and the contractor; any significant change in the mud-logging program that adds to contractor costs will have to be covered under "change" orders. Such program changes and added costs also will alter the projected cost-per-interval figure.

As observed previously, when stand-alone equipment is to be used, delivery and installation generally is made by the supplier. Setup will be prior to spudding. Because training in use of leased equipment generally is part of the setup service, operator personnel generally have to be at the drillsite for prespud familiarization with stand-alone equipment.

Exercise 1.

What do the following stand for?

a. MWD

b. d-exp

c. H₂S

d. well-kill

e. stand-alone

Solution 1:

a. MWD is measurement while drilling; it generally indicates that sensors have been placed behind the bit in the drillstring.

b. d-exp is a calculated drillability of rock that removes some drilling operation variables.

c. H₂S is hydrogen sulfide.

d. Well-kill is a procedure used to control a well kick.

e. Stand-alone is the name commonly applied to equipment supplied without an operator.

 

References and Additional Information

References

The following list of texts can provide a more detailed and technical account of specific technologies involved in modern mud logging.

Anadrill. 1984a. Drilling engineering and logging training for Anadrill (DELTA) manual. vol. 1. Sugar Land, Texas: Anadrill, Inc.

Anadrill. 1984b. Techniques for we/I-site logging, pressure detection and M. W. D. Sugar Land, Texas: Anadrill, Inc.

Anderson, G. 1975. Coring and core analysis handbook. Tulsa: Petroleum Publishing Company.

Baroid. 1985a. Mud logging service descriptions. Sugar Land, Texas: NL Baroid Logging Systems, NL Industries, Inc.

Baroid. 1985b. Measurements-while-drilling technical specifications. Sugar Land, Texas: NL Baroid Logging Systems, NL Industries, Inc.

Belotti, P., and D. Giacca. 1978. Pressure evaluation improves drilling programs. Oil and Gas Jour. Sept 11: 76-85.

Bingham, M. G. 1965. A new approach to interpreting rock drillability. Tulsa: Petroleum Publishing Company.

Calmer, S. H. 1979. H2S detector aids drilling safety, data. Oil and Gas Jour. Nov 19:

Clementz, D. M., G. J. DeMaison, and A. R. Daly. 1979. Wellsite geochemistry by programmed pyrolysis. Offshore Technology Conference Proceedings. OTC 3410. Houston

Coope, D. A., and W. E. Hendricks. 1984. Formation evaluation using measurements recorded while drilling. SPWLA Twenty-Fifth Annual Logging Symposium (June).

Core Lab. 1979a. Hydrocarbon well logging basic manual. Dallas: Well Logging Training Services, Core Laboratories, Inc.

Core Lab. 1979b. Identification of cuttings samples. Dallas: Well Logging Training Services, Core Laboratories, Inc.

Exlog. 1985a. Field geologist 's training guide (ed. A. Whittaker). Boston: IHRDC.

Exlog. 1985b. Formation evaluation: Geological procedures (ed. A. Whittaker). Boston: D. Reidel Publishing Company/IHRDC.

Exlog. 1985c. Mud logging Principles and interpretation (ed. A. Whittaker). Boston: IHRDC.

Exlog. 1985d. Theory and application of drilling fluid hydraulics (ed. A. Whittaker). Boston: IHRDC.

Exlog. 1985e. Theory and evaluation of formation pressures: A pressure detection reference handbook (ed. A. Whittaker). Boston: D. Reidel Publishing Company/IHRDC.

Exxon. 1985. Mud log and strip log: Standards, instructions, examples. Denver: Western Exploration Division, Exxon Company, U.S.A.

Gary, M., R. McAfee, Jr., and C. L. Wolf (eds). 1972. Glossary of geology. Washington, D. C.: American Geological Institute.

Gill, J. A. 1983. Hard rock drilling problems explained by hard rock pressure plots. IADC/SPE 11377. New Orleans drilling conference (February).

Goldsmith, R. G. 1972. Why gas cut mud is not always a problem. World Oil. 175(5):51-54, 101.

Haworth, J. H., M. Sellens, and A. Whittaker. 1985. Interpretation of hydrocarbon shows using light (C1 -C5) hydrocarbon gases from mud-log data. AAPG Bulletin 69(8): 1305-10 (August).

Hopkins, E. A. 1967. Factors affecting cuttings removal during rotary drilling. Jour. Pet. Tech. (June) 807-814; Trans AIME, 240.

Jordan, J. S., and 0. J. Shirley. 1966. Application of drilling performance data to overpressure detection. Jour. Pet. Tech. 18(11):1387-1394.

Magcobar, 1976. Data engineering manual. Houston: Dresser Magcobar Data Systems.

Martin, C.A., 1986. Wellsite applications of integrated MWD and surface data. IADC/SPE Dallas meeting (February).

Mercer, R. F., and J. B. McAdams. 1981. Hydrocarbon well logging (mud logging): Basic principles and needs for standards. SPWLA Speakers' Notes, Houston chapter (February).

Rehm, B., and R. McClendon. 1971. Measurements of formation pressure from drilling data. SPE Reprint Series. 3601(6a). (rev. 1973).

Robertson. 1985. Geochemical evaluation of a hypothetical well illustrating graphical representation of geochemical data. Report #483. Houston: Robertson Research (U.S.), Inc.

SPWLA. 1983. Recommended practices for hydrocarbon well logging. Houston: Society of Professional Well Log Analysts.

Swanson, R. G. 1981. Sample examination manual. Tulsa: AAPG.

Taylor, K. 0., and W. Anderson. 1984. Electronic system speeds drilling time. Oil and Gas Jour. (September).

Waples, D.W. 1985. Geochemistry in petroleum exploration. Boston: IHRDC.

Whittaker, A. 1985. Sample and core handling and analysis. Boston: IHRDC.

Zoeller, W. A. 1978. Instantaneous log is based on surface drilling data. World Oil (January).

Zoeller, W. A. 1974. Rock properties determined from drilling response. Petro Eng. (July).

 

 

 

Standard Abbreviations for Lithologic Descriptions

(Note: Abbreviations for nouns always begin with a capital letter.)

Word	Abbreviation
about	abt
above	ab
absent	abs
abundant	abd
acicular	acic
agglomerate	Aglm
aggregate	Agg
algae, algal	Alg, alg
allochem	Allo
altered	alt
alternating	altg
ammonite	Amm
amorphous	amor
amount	amt
and	&
angular	ang
anhedral	ahd
anhydrite (-ic)	Anhy, anhy
anthracite	Anthr
aphanitic	aph
appears	ap
approximate	apprx
aragonite	Arag
arenaceous	aren
argillaceous	arg
arkose (-ic)	Ark, ark
as above	a.a..
asphalt (-ic)	Asph, asph
assemblage	Assem
associated	assoc
at	@
authigenic	authg
average	Av, av
band (-ed)	Bnd, bnd
basalt (-ic)	Bas, bas
basement	Bm
become (-ing)	bcm
bed (-ed)	Bd, bd
bedding	Bdg
bentonite (-ic)	Bent, bent
bitumen (-inous)	Bit, bit
bioclastic	biocl
bioherm (-al)	Bioh, bioh
biomicrite	Biomi
biosparite	Biosp
biostrom (-al)	Biost, biost
biotite	Biot
birdseye	Bdeye
black (-ish)	blk, blksh
blade (-ed)	Bid, bid
blocky	blky
blue (-ish)	bl, blsh
bore (-ed, -ing)	Bor, bor
bottom	Btm
botryoid (-al)	Bot, bot
boulder	Bid
boundstone	Bdst
brachiopod	Brach
brackish	brak
branching	brhg
break	Brk, brk
breccia (-ted)	Brec, brec
bright	brt
brittle	brit
brown.	brn
bryozoa	Bry
bubble	Bubl
buff	bu
burrow (-ed)	Bur, bur
calcarenite	Clcar
calcilutite	Clclt
calcirudite	Clcrd
calcisiltite	Clslt
calcisphere	Clcsp
calcite (-ic)	Calc, calctc
calcareous	calc
caliche	cche
carbonaceous	carb
carbonized	cb
cavern (-ous)	Cav, cav
caving	Cvg
cement (-ed, ing)	Cmt, cmt
cephalopod	Ceph
chalcedony (-ic)	Chal, chal
chalk (-y)	Chk, chky
charophyte	Char
chert (-y)	Cht, cht
chitin (-ous)	Chit, chit
chlorite (-ic)	Chlor, chlor
chocolate	choc
circulate (-ion)	circ, Circ
clastic	clas
clay (-ey)	Cl, cl
claystone	Clst
clean	cln
clear	clr
cleavage	Clvg
cluster	Clus
coal	C
coarse	crs
coated (-ing)	cotd, cotg, Cotg
coated grains	cotd gn
cobble	Cbl
color (-ed)	Col, col
common	com
compact	cpct
compare	cf
concentric	cncn
conchoidal	conch
concretion (-ary)	Conc, conc
conglomerate (-ic)	Cgl, cgl
conodont	Cono
considerable	cons
consolidated	consol
conspicuous	conspic
contact	Ctc
contamination (-ed)	Contam, contam
content	Cont
contorted	cntrt
coquina (-oid)	Coq, coqid
coral, coralline	Cor, corln
core	c,
cove red	cov
cream	crm
crenulated	cren
crinkled	crnk
crinoid (-al)	Crin, crinal
cross	x
cross-bedded	x-bd
cross-laminated	x-lam
cross-stratified	x-strat
crumpled	crpld
crystocrystalline	crpxln
crystal (-line)	Xi, xln
cube, cubic	Cub, cub
cuttings	Ctgs
dark (-er)	dk, dkr
dead	dd
debris	Deb
decrease (-ing)	Decr, decr
dense	dns
depauperate	depau
description	Descr
detrital	detl
devitrified	devit
diabase	Db
diagenesis (-etic)	Diagn, diagn
diameter	Dia
disseminated	dissem
distillate	Dist
ditto	"or do
dolomite (-ic)	Dol, dol
dominant (-ly)	dom
drilling	drlg
drilistem test	DST
drusy	dru
earthy	ea
east	E
echinoid	Ech
elevation	Elev
elongate	elong
embedded	embd
equant	eqnt
equivalent	Equiv
euhedral	euhd
euxinic	eux
evaporite (-itic)	Evap, evap
excellent	ex
exposed	exp
extraclast (-ic)	Exclas, exclas
extremely	extr
extrusive rock, extrusive	Exv, exv
facet (-ed)	Fac, fac
faint	fnt
fair	fr
fault (-ed)	Fit, fit
fauna	Fau
feet	Ft
feldspar (-athic)	Fspr, fspr
fenestra (-al)	Fen, ten
ferruginous	ferr
fibrous	fibr
tine (-ly)	t, fnly
fissile	fis
flaggy	fIg
flake, flaky	FIk, flk
fiat	ti
floating	fltg
flora	Flo
fluorescence (-ent)	Fluor, fluor
foliated	fol
toot	Ft
foraminefera (-al)	Foram, foram
formation	Fm
fossil (-iferous)	Foss, toss
fracture(-d)	Frac, frac
fragment (al)	Frag, frag
frequent	freq
fresh	frs
friable	fri
fringe (-ing)	Frg, frg
frosted	fros
frosted quartz grains	F.Q.G.
fucoid (-al)	Fuc, fuc
fusulinid	Fus
gabbro	Gab
gastropod	Gast
gas	G
generally	gen
geopetal	gept
gilsonite	Gil
glass (-y)	Glas, glas
glauconite (-itic)	Glauc, glauc
Globigerina (-inal)	Glob, glob
gloss (-y)	Glos, glos
gneiss (-ic)	Gns, gns
good	gd
grading	grad
grain (-s, -ed)	Gr, gr
grainstone	Grst
granite	Grt
granite wash	G.W.
granule (-ar)	Gran, gran
grapestone	grapst
graptolite	Grap
gravel	Grv
gray, grey (-ish)	gry, grysh
graywacke	Gwke
greasy	gsy
green (-ish)	gn, gnsh
grit (-ty)	Gt, gt
gypsum (-iferous)	Gyp, gyp
hackly	hkl
halite (-iferous)	Hal, hal
hard	hd
heavy	hvy
hematite (-ic)	Hem, hem
Heterostegina	Het
heterogeneous	hetr
high (-ly)	hi
homogeneous	hom
horizontal	hor
hydrocarbon	Hydc
igneous rock (igneous)	Ig, ig
impression	imp
inch	in
inclusion (ded)	Incl, incl
increasing	incr
indistinct	indst
indurated	ind
Inoceramus	Inoc
in part	I.P.
insoluble	insl
interbedded	intbd
intercalated	intercal
intercrystalline	intxln
intergranular	intgran
intergrown	intgn
interlaminated	intrlam
interparticle	intpar
intersticies (-itial)	Intst, intst
intraclast (-ic)	Intclas, intclas
intraparticle	intrapar
intrusive rock, intrusive	Intr, intr
invertebrate	Invtb
iridescent	irid
ironstone	Fe-st
irregular (-ly)	irr
isopachous	iso
jasper	Jasp
joint (-ed, -ing)	Jt, jt
kaolin (-itic)	Kao, kao
lacustrine	lac
lamina (-tions, -ated)	Lam, lam
large	lge
late rite (-itic)	Lat, lat
lavender	lav
layer	Lyr
leached	lchd
lens, lenticular	Len, lent
light	it
lignite (-itic)	Lig, lig
limestone	Es
limonite (-itic)	Lim, lim
limy	lmy
lithic	lit
lithographic	lithgr
lithology (-ic)	Lith, lith
little	Ltl
littoral	litt
local	loc
long	lg
loose	lse
lower	l
lustre	Lstr
lutite	Lut
macrofossil	Macrofos
magnetite magnetic	Mag, mag
manganese,
manganiferous	Mn, mn
marble	Mbl
marl (-y)	Mrl, mrl
marlstone	Mrlst
marine	marn
maroon	mar
massive	mass
material	Mat
matrix	Mtrx
maximum	max
medium	m or med.
member	Mbr
meniscus	men
metamorphic rock,	Meta
metamorphic (-osed)	meta, metaph
mica (-ceous)	Mic, mic
micrite (-ic)	Micr, micr
microcrystalline	microxln
microfossil (-iferous)	Microfos, microfos
micrograined	micgr
micro-oolite	Microol
micropore (-osity)	Micropor, micropor
microspar	Microspr
microstylolite	Microstyl
middle	Mid
miliolid	Milid
milky	mky
mineral (-ized)	Min, min
minor	mnr
moderate	mod
mold (-ic)	Mol, mol
mollusc	Moil
mosaic	mos
mottled	mott
mud (-dy)	md, mdy
mudstone	Mdst
muscovite	Musc
nacreous	nac
nodules (-ar)	Nod, nod
north	N
no sample	n.s.
no show	n/s
novaculite	Novac
no visible porosity	n.v.p..
numerous	num
occasional	occ
ochre	och
oil	O
oil source rock	OSR
olive	olv
ooid (-al)	OO, oo
oolicast (-ic)	Ooc, ooc
oolite (-itic)	Ool, ool
oomold (-ic)	Oomol, oomol
oncolite (-oidal)	Onc, onc
opaque	op
orange (-ish)	or, orsh
Orbitolina	Orbit
organic	org
orthoclase	Orth
orthoquartzite	O-Otz
Ostracod	Ostr
overgrowth	ovgth
oxidized	ox
oyster	Cyst
packstone	Pkst
paper (-y)	Pap, pap
part (-ly)	Pt, pt
particle	Par, par
parting	Ptg
parts per million	PPM
patch (-y)	Pch, pch
pebble (-ly)	PbI, pbl
pelecypod	Pelec
pellet (-al)	Pel, pel
pelletoid (-al)	Peld, peld
pendular (-ous)	Pend, pend
permeability (-able)	Perm, k, perm
petroleum, petroliferous	Pet, pet
phlogopite	Phlog
phosphate (-atic)	Phos, phos
phyllite, phyllitic	Phyl, phyl
phreatic	phr
pink	pk
pinkish	pkish
pin-point (porosity)	p.p.
pisoid (-al)	Piso, piso
pisolite, pisolitic	Pisol, pisol
pitted	pit
plagioclase	Plag
plant	Plt
plastic	plas
platy	pity
polish, polished	Pol, pol
pollen	Poln
polygonal	poly
porcelaneous	porcel
porosity, porous	Por, , por
possible (-ly)	poss
predominant (-ly)	pred
preserved	pres
primary	prim
probable (-ly)	prob
production	Prod
prominent	prom
pseudo-	ps
pseudo oolite (-ic)	Psool, psool
pumice-stone	Pst
purple	purp
pyrite (-itized, -itic)	Pyr, pyr
pyrobitumen	Pybit
pyroclastic	pyrcl
quartz (-ose)	Qtz, qtz
quartzite (-ic)	Qtzt, qtzt
radial (-ating)	Rad, rad
radiaxial	Radax
range	rng
rare	r
recemented	recem
recovery (-ered)	Rec, rec
recrystallized	rexlzd
red (-ish)	rd, rdsh
reef (-old)	Rf, rf
remains	Rem
replaced (-ment)	rep, Repl
residue (-ual)	Res, res
resinous	rsns
rhomb (-ic)	Rhb, rhb
ripple	Rpl
rock	Rk
round (-ed)	rnd, rndd
rounded, frosted, pitted	r.f.p.
rubble (-bly)	Rbl, rbl
rudist	Rud
saccharoidal	sacc
salt (-y)	SA, sa
salt and pepper	s & p
salt water	S.W.
same as above	a.a
sample	Spl
sand (-y)	Sd, sdy
sandstone	Sst
saturation (-ated)	Sat, sat
scarce	scs
scattered	scat
schist (-ose)	Sch, sch
scolecodont	Scol
secondary	sec
sediment (-ary)	Sed, sed
selenite	Sel
shale (-ly)	Sh, sh
shell	Shl
shelter porosity	Shlt por
show	Shw
siderite (-itic)	Sid, sid
sidewall core	S.W.C.
silica (-iceous)	Sil, sil
silky	slky
silt (-y)	Sit, sit
siltstone	Sltst
similar	sim
skeletal	skel
slabby	sib
slate (-y)	Sl, sl
slickenside (-d)	Slick, slick
slight (-ly)	sli, slily
small	sml
smooth	sm
soft	sft
solution, soluble	Sol, sol
somewhat	smwt
sorted (-ing)	srt, srtg
south	S
spar (-ry)	Spr, spr
sparse (-ly)	sps, spsly
speck (-led)	Spk, spkld
sphalerite	Sphal
spherule (-itic)	Spher, spher
spicule (-ar)	Spic, spic
splintery	splin
sponge	Spg
spore	Spo
spotted (-y)	sptd, spty
stain (-ed, ing)	Stn, stn
stalactitic	stal
strata (-ified)	Strat, strat
streak (-ed)	Strk, strk
striae (-ted)	Stri, stri
stringer	strgr
stromatolite (-itic)	Stromlt, stromlt
stromatoporoid	Strom
structure	Str
stylolite (-itic)	Styl, styl
subangular	sbang
sublithic	sblit
subrounded	sbrndd
sucrosic	suc
sulphur, sulphurous	Su, su
superficial oolite (-ic)	Spfool, spfool
surface	Surf
syntaxial	syn
tabular (-ate)	tab
tan	tn
terriginous	ter
texture (-d)	Tex, tex
thick	thk
thin	thn
thin-bedded	t.b.
thin section	T.S.
throughout	thru
tight	ti
top	Tp
tough	tgh
trace	Tr
translucent	trnsl
transparent	trnsp
trilobite	Tril
tripoli (-itic)	Trip, trip
tube (-ular)	Tub, tub
tuff (-aceous)	Tf, tf
type (ical)	Typ, typ
unconformity	Unconf
unconsolidated	uncons
underclay	Uc
underlying	undly
uniform	uni
upper	u
vadose	Vad, vad
variation (-able)	Var, var
varicolored	varic
variegated	vgt
varved	vrvd
vein (-ing,	-ed)
Vn, vn
veinlet	Vnlet
vermillion	verm
vertebrate	vrtb
vertical	vert
very	v
very poor sample	V.P.S
vesicular	ves
violet	vi
visible	vis
vitreous (-ified)	vit
volatile	volat
volcanic rock, volcanic	volc, Volc
vug (-gy)	Vug, vug
wackestone	Wkst
washed residue	W.R
water	Wtr
wavy	wvy
waxy	wxy
weak	wk
weathered	wthd
well	WI, wi
west	w
white	wh
with	wi
without	w/o
wood	Wd
yellow (-ish)	yel, yelsh,
zircon	Zr
zone	Zn

(From Swanson, 1981, reprinted by permission of AAPG).