Geological And Operational Summary ST. GEORGE BASIN COST .
Geological and Operational SummaryST. GEORGE BASIN COST NO. 1 WELLUnited Stat
GEOLOGICAL AND OPERATIONAL SUMMARYST. GEORGE BASIN COST NO. 1 WELLBERING SEA, ALASKARonal d F. Turner ( E d i t o r )Colleen M. McCarthyC. Drew ComerJohn A. LarsonJ. G. BolmArthur C. Banet, J r .A l l e n J. AdamsOCS Report MMS 84-0016March 1984Repri nted September 1985UNITED STATES DEPARTMENT OF THE INTERIORMINERALS MANAGEMENT SERVICEAny use o f trade names i s f o r d e s c r i p t i v e purposes o n l y and does n o tcons ti t u t e endorsement o f these products by t h e M i neral s Management Service.
CONTENTSPage1Introductionoperational SummaryShall ow geologic s e t t i n gSeismic r e f l e c t i o n c o r r e l a t i o n andvel o c i t y analysi s3rnPal eontol ogy and b i os t r a t i g r a p h yL i tho1 ogy and we1 1 1og i n t e r p r e t a t i o nOrganic geochemi s t r yEnvi ronmental NSFigure 1.Location map2.Final l o c a t i o n p l a t3.Graph showing d a i l y d r i l l i n g progress4.Schematic diagram showing casing s t r i n g s ,plugging and abandonment program5.Changes w i t h depth o f d r i l l i n g mud p r o p e r t i e s86.Location map o f S t . George Basin, COST-wells,and U.S. Geological Survey seismic l i n e s127.Synthetic sei smogram158.Time-stratigraphic column and s e i m i c p r o f i l e179.I n t e r v a l v e l o c i t i e s and time-depth curvefrom t h e sonic l o g10.Comparison between time-depth curves f o r t h e COST No. 1and No. 2 w e l l siii519
ILLUSTRATIONS (cont.)Page-11.Compari son between i n t e r v a l v e l o c i t i e s f o r theCOST No. 1 and No. 2 w e l l s12.U.S. Geological Survey seismic 1i n e s 16and 1713.S t r a t i g r a p h i c summary, paleobathymetry , andc o r r e l a t i o n o f COST No. 1 and No. 2 we1 1s14.D e s c r i p t i o n o f conventional core 115.Description o f conventional core 216.Description o f conventional core 417.Description o f conventional core 518.D e s c r i p t i o n o f conventional core 619.Description o f conventional core 720.D e s c r i p t i o n o f conventional core 821.Description o f conventional core 922.Description o f conventional core 1023.P l o t o f average p o r o s i t y against depth f o rsandstone sampl es from conventional cores24.P l o t o f average p o r o s i t y against averagepermeability f o r sandstone samples fromconventional cores25.Temperature l o g data26.Analysis o f walnut h u l l and gas chromatogram o fwalnut h u l l C15 e x t r a c t showing a1kanedistribution27.Van Krevelen diagram (atomic r a t i o s ) f o r kerogens28.Chromatograms from extracted CSI f r a c t i o n showingchanges i n p a r a f f i n d i s t r i b u t i o n and naphthenesfrom c u t t i n g s samples20
PLATESP l a t e 1.2.Stratigraphic column and summary chart o f geologic dataOrganic geochmi stryTABLESTab1 e 1.Conventional coresI2.Basalt chemistry data3.Potassium-argon ages o f b a s a l t samples4.Porosity and pemeabil i t y5.Comparison o f organic richness6.Elemental analyses and atomic r a t i o s o f kerogen samples7.61% compositions
Figure i. Location map showing St. George Basin Sale 70 a'rea and-COST No. I and No. 2 Wells.
Geological and Operational SummarySt. George Basin COST No. 1 We11Bering Sea, AlaskaRonald F. Turner, E d i t o r.JINTRODUCTIONTi tl e 30, Code o f Federal Regulations (CFR) , paragraph 251.1 4 s t i p u l atest h a t geological data and processed geological information obtained from DeepStratigraphic Test wells d r i l l e d on the Outer Continental She1f (OCS) be madeavailable for public inspection 60 calendar days a f t e r the issuance o f thef i r s t Federal lease w i t h i n 50 nautical miles o f the well s i t e o r 10 years a f t e rcanpletion o f the w e l l i f no leases are issued. Tracts w i t h i n t h i s distance o fthe f i r s t St. George Basin Deep Stratigraphic Test well (designated the ARC0S t . George Basin COST No. 1 Well by the operator and hereafter referred to asthe well o r the No. 1 well) were offered f o r lease i n Sale 70 on A p r i l 12,1983. One hundred-fifty bids on 97 t r a c t s were received w i t h the t o t a l highbids amounting t o 427,343,829.68.Ninety-six bids were accepted and one wasrejected. The e f f e c t i v e issuance date o f the leases i s March 1 , 1984.The S t . George Basin COST No. 1 we1 1 was completed on September 22, 1976,i n Block 459, 1ocated approximately 105 miles southeast o f S t . George Island,Alaska ( f i g . 1). The well data l i s t e d i n the appendix are available f o r publicinspection a t Mineral s Management Service, Fie1d Operations, 1ocated a t800 "A" Street, Anchorage, Alaska 99501.A l l depths are measured i n f e e t from the K e l l y Bushing (KB), which was 98f e e t above sea level. For the most part, measurements are given i n U.S.Customary Units except where s c i e n t i f i c convention dictates metric usage. Aconversion c h a r t i s provided. The i n t e r p r e t a t i o n s contained herein are c h i e f l ythe work o f Minerals Management Service (MMS) personnel, although substantialcontributions were made by geoscience consulting companies.t1EQUIVALENT MEASUREMENT UNITS1111inch 2.54 centimetersf o o t 0.3048 meters t a t u t e m i l e 1.61 k i l m t e r snautical m i l e1.85 kilometers 1.15 s t a t u t e miles 6,080 f e e t1 knot 1 nautical milelhourTemperature in degrees Fahrenhei tless 32, divided by 1.8 degrees Cel s i us1 pound 0.45 kilogram1 poundlgallon 119.83 kilograms/cubic meter1 poundlsquare inch 0.07 kilogram/square centimeter1 gallon 3.78 l i t e r s (cubicdecimeters)1 barrel 42 U.S. gallons 0.16-cubic meter
OPERATIONAL SUMMARYbyColleen M. McCarthyThe S t . George Basin COST No. 1 well was d r i l l e d by t h e Ocean Ranger, asel f-propel l e d semi submersible d r i l l i n g r i g . The Ocean R a n g e n O D E C O ,Inc., was b u i l t i n 1976 by HI Hiroshima Shipyard a n d n ? j E - R o r k s and wasgiven the c l a s s i f i c a t i o n ABSAMS A - 1 (M), column-stabilized mobile d r i l l i n gu n i t . The r i g was designed f o r d r i l l i n g i n water up t o 3000 f e e t deep, 100knot winds, and 110-foot waves w i t h a corresponding wave p e r i o d o f 15 secondsand a surface c u r r e n t o f 3 knots. The Ocean Ranger was inspected before d r i l l i n gbegan, and operations were observed by U . S . G c a 1 Survey (USGS, now Mineral sManagement Service) personnel throughout the d r i l l i n g p e r i o d t o ensure compliancew i t h Department o f I n t e r i o r regul a t i o n s and orders.-Cold Bay and Dutch Harbor, Alaska, were used as operational bases. ColdBay, approximately 170 miles from t h e we1 1 l o c a t i o n , was t h e a i r base. Twoseagoing supply vessels transported d r i l l ing m a t e r i a l s and suppl i e s , i n c l u d i n gf u e l , from Dutch Harbor to the r i g . A t l e a s t one standby vessel was w i t h i n a1-mile radius o f the r i g a t a l l times. The supply vessels were a l s o used f o rtowing and anchor handling. Depending on weather, t i m i n g , and a v a i l a b i l ity ,m a t e r i a l s and equipment were transported between Dutch Harbor and the Alaskamainland by these supply boats, barges, o r other sui tab1 e vessels.Helicopters c e r t i f i e d f o r instrument f l i g h t were used t o t r a n s p o r t personnel,groceries, and l i g h t w e i g h t equipment between the r i g and Cold Bay. Personnel,equipment, and supplies were transported t o and from t h e shore base and Anchorageby b o t h chartered and commercial a i r c a r r i e r s .The No. 1 we1 1 was spudded a t 1630 hours Alaska Standard Time, J u l y 2,1976. D r i l l i n g was completed 83 days l a t e r on September 22, 1976, a t a t o t a ldepth (TO) o f 13,771 feet. A f t e r logging and c o r i n g operations were completed,t h e we1 1 was plugged and abandoned on October 2, 1976, and the r i g was released.A t l a n t i c R i c h f i e l d Company (ARCO) acted as t h e operator f o r i t s e l f and thef o l lowing nineteen petroleum companies t h a t shared expenses f o r the we1 1 :Arnerada Hess CorporationAMOCO Production CompanyB r i t i s h Petroleum, Inc.C i t i e s Service CompanyContinental O i l CompanyExxon Company, U.S.A.Getty O i l CompanyG u l f Energy and Mineral s Company, U.S.A.Marathon O i l CompanyMobil . O i l CorporationPennzoil CompanyP h i l 1i p s Petroleum CompanytI
GEODET lC POSI T I ONL AT. 55O 32' 3 4.64" N. 0 . 1 6 6 17.50" 5 7 'W.U N I V E R S A L TRANSVERSE MERCATORCOORDINATES, ZONE 3, in M E T E R S .y 6,156,734.6x 376,648.8Figure 2. Final location plat showing the position of the COSTNo. 1 Well, St. George Basin, Alaska
She11 O i l CompanySkel l y O i l CompanyStandard O i l o f C a l i f o r n i aSun O i l CompanyTenneco O i l CompanyTexaco, Inc.Union O i l Company o f Cal i f o r n i aThe No. 1 w e l l was located a t l a t 55 32'34.6437" N., long 166 57'17.5001nW., o r UTM coordinates (zone 3) X 376,648.83 m and Y 6,156,734.57m. Thef i n a l we1 1 s i t e i s shown i n f i g u r e 2. Water depth a t the l o c a t i o n i s 442feet. A l l measurements were made from the K e l l y Bushing, which was 98 f e e tabove the water l i n e and 540 f e e t above the mud l i n e . The maximum deviationfrom v e r t i c a l was 2 3/4 degrees, and the well was d r i l l e d , f o r the most part,w i t h l e s s than 1 degree deviation.ID r i l ling s t i p u l a t i o n s requi red the operator t o provide the M i neral sManagement Service (formerly USGS) with a11 well logs, samples, core slabs,geologic information, and operational reports.DRILLING PROGRAMThe No. 1 we1 1 was d r i l l e d using two 17 1/2-inch d r i l l b i t s t o a depth o f1600 feet, and deepened w i t h twenty-seven 8 1/2-inch b i t s t o TD. Additionalb i t s were used f o r hole opening, t o d r i l l through cement, f o r clean-out t r i p s ,and f o r the conventional coring program. D r i l l i n g rates ranged from 3 t o 2700feet/hour. The r a t e gradually decreased from an average o f 1600 feet/hour a t2600 f e e t t o 100 feet/hour a t 5700 feet. A t t h i s depth s o f t e r sediments wereencountered and the d r i l l i n g r a t e increased t o 200 feet/hour down t o 6500feet. From t h i s depth, the r a t e again gradually decreased t o an average o f 10feet/hour a t TD. The d a i l y d r i l l i n g progress i s shown i n f i g u r e 3.Three s t r i n g s o f casing were s e t i n the well as shown i n f i g u r e 4. The30-inch casing was s e t a t 642 f e e t w i t h 776 sacks o f cement; the 20-inch casingwas s e t a t 1556 f e e t w i t h 1950 sacks o f cement; the 13 3/8-inch casing was s e ta t 4833 f e e t w i t h 1900 sacks o f cement. Class G cement was used f o r a l l casings.While cementing the 13 3/8-inch casing, l o s s o f c i r c u l a t i o n problems wereencountered. Penni ssion was received from t h e USGS t o d r i l l out the 13 3/8-inchcasing shoe, and two Cement Bond Logs were run w i t h no i n d i c a t i o n o f cementbonding. A f t e r squeeze cementing t o ensure proper bonding o f the casing w i t hthe formation, and running a leak-off t e s t , d r i l l i n g was continued w i t h nof u r t h e r problems.The abandonment procedure i s also shown i n f i g u r e 4. A cement r e t a i n e rwas s e t between 4,730 and 4,780 f e e t w i t h cement 70 f e e t above and 200 f e e tbelow the retainer. The 13 3/8-inch casing was c u t a t 740 feet; both the 30inch and 20-inch casings were c u t a t 555 feet. A t the surface, a cement plugwas s e t between 630 and 840 feet.L
D a y o f MonthFigure 3. Graph showing daily drilling progress for t h eSt. George Basin COST No. 1 Well.
-Kelly Bushing,Mean0'Sea L e v e l 9 8 'Mud L i n e 5 4 0 'I/3 0 " Cut a t 5 5 5 '2 0 " Cut a t 5 5 5 '1 3 / Cut" a t 740'30" Casing a tCementSurface Plug630'-840'20'' Casing a t 1,556'Estimated Cement T o pCement R e t a i n e rSet between4 , 7 3 0 ' - 4,780'1378" Casing a t 4 , 8 3 3 'Cement P l u g2 0 0 ' below r e t a i n e r7 0 ' above r e t a i n e rFigure 4. S c h e m a t i c d i a g r a m showing c a s i n g strings, plugging,a n d abandonment program, St. G e o r g e B a s i n C O S T No. 1 Well.
DRILLING MUDChanges i n selected d r i l l i n g mud properties a r e shown i n f i g u r e 5. Seawater and spotted viscous gel p i l l s were used as d r i l l i n g f l u i d down to 1580f e e t . A t t h i s depth, fresh-water d r i l l i n g mud w i t h a weight of 8.6 pounds/gallonand a v i s c o s i t y o f 43 seconds displaced t h e seawater. Mud weight was increasedt o 9.0 pounds/gallon a t 4200 feet, reached 9.6 pounds/gallon a t 10,300 feet,and remained a t t h a t weight to TD. The v i s c o s i t y o f the mud f l u c t u a t e d between35 and 60 seconds i n t h e f i r s t 5400 f e e t and averaged about 45 seconds f o r t h eremainder o f t h e we1 1. h d pH averaged 11.0 w i t h m i nor f l u c t u a t i o n s . Chlorideconcentrations began w i t h 3200 ppm, decreased t o 1400 ppm a t 8950 feet, and2000 ppm a t TD. Mud logging services were provided by The Analysts.SAMPLES AND TESTST h i r t e e n conventional cores were obtained and analyzed f o r p o r o s i t y ,permeability , g r a i n density , paleontology , depositional environment, andlithology.Table 1 Conventional CoresCore No.Interval (feet)Recovered ( f e e t )-12345678910111213473003018.5184145122142399Three series o f sidewall cores were taken. A t 4921 feet, 150 cores wererecovered i n f o u r runs w i t h 12 m i s f i r e s , 11 empty b u l l e t s , and one l o s t b u l l e t .A t 10,217 feet, 363 cores were recovered i n 435 attempts, l e a v i n g 16 b u l l e t s i nt h e hole. A t 13,006 feet, 49 cores were attempted, 37 recovered, and 12 b u l l e t swere l o s t . F i v e hundred and f i f t y successful cores were obtained.There were no d r i l l stem t e s t s made on t h i s we1 1.The types o f l o g s and t h e i n t e r v a l s logged are as follows:
MUD WEIGHT-(Ibs/ al)0.5IS.00.5 10.0IMUD VISCOSITYCHLORIDES(seconds)( X 1,000 ppm1.0I1.6 L O L.6 3.0 1.8IIMUD pH10I1I tI14,000Figure 5. Changes with depth o f drilling mud properties, includingmud weight, viscosity, t o t a l chlorides, and pH, St.George B a s i n C O S T No. I Well.
4921 f e e t t o 1553 f e e tDual Induction Laterol og/Spontaneous Potenti a1Compensated Formation Density Sonic LoglNeutron Gamma RayMicro-Lateral LoglCal i p e r and Spontaneous Potenti a1Vel oci t y SurveyHigh Resolution Continuous D i pmeterRepeat Formation TesterHigh Resolution Temperature SurveyCement Bond Log10.217 f e e t t o 4921 f e e tDual Induction Laterol og/Spontaneous Potenti a1Borehole Compensated Sonic LogSonic LogDensity Neutron LogVel oci t y SurveyLong-Spaced Sonic LogMicro- Lateral LogCement Bond LogHigh Resolution Continuous DipmeterICa1i p e rHigh Resolution Temperature LogRepeat Formation Tester13,006 f e e t t o 10,217 f e e tDual Induction LaterologBorehol e Compensated Sonic LogVel oci t y SurveyCompensated Neutron Log Compensated Formation Density Log/GammaRay/Cal iperLong-Spaced Sonic LogMicro-Lateral LogHigh Resolution Continuous D i pmeterTemperature SurveyRepeat Formation Tester-13.771 f e e t t o 13.006 f e e tDual Induction LaterologBorehol e Compensated Soni c/Gamma Ray/Cal iperVel oci t y SurveyHigh Resolution Temperature SurveyWEATHERWeather conditions were monitored from l a t e June through the end o f September1976. During t h i s period, waves o f 10 f e e t o r more occurred on 10 days, w i t h amaximum wave height of 16 f e e t i n September. Wind speeds reached 53 miles perhour on August 30, b u t were n o t above 40 miles per hour on any other day. Thetemperature was never below 40" F o r higher than 53O F.
SHALLOW GEOLOGIC SETTINGbyC. Drew ComerThe shallow geologic c h a r a c t e r i s t i c s of the d r i l l s i t e were i d e n t i f i e d bya high-resolution geophysical survey (BBN-Geomarine Services Company, 1976) anda 236-foot-deep geotechnical corehol e ( Woodward-Clyde Consultants, 1976a). Thesestudies eval uated potential shal low d r i l l i ng hazards. A more d e t a i l ed discussionof the regional environmental geology may be found i n the Final EnvironmentalImpact Statement (U .S. Mineral s Management Service, 1982), Gardner and o t h e r s(19791, and Comer ( i n press).REGIONAL ENVIROElMENTAL GEOLOGY.3The S t . George basin i s located on the Outer Continental She1 f of theBering Sea i n water depths ranging from 340 t o 530 f e e t . The sea f l o o r ise s s e n t i a l l y f l a t and f e a t u r e l e s s w i t h an average regional slope of less thanone degree. According t o Gardner and o t h e r s (1980), the s u r f i c i a l sedimentsc o n s i s t mostly of unconsol i d a t e d s i l t and s i l t y sand w i t h 1ow concentrationsof volcanic ash and diatoms and a r e mostly r e l i c t f r a n a period of low s e al e v e l . Very l i t t l e recent sediment i s being transported i n t o the area.Glacial a c t i v i t y i n the Pleistocene caused lower sea l e v e l s and exposedmuch of the shel f. The o u t e r Bering Sea shelf probably f l u c t u a t e d betweensedi ment-starved condi ti ons , a s a t present, and sediment-enriched condi t i o n s ,when lower sea 1eve1 s made more sediment a v a i l a b l e by exposing the inner andmiddle shel f to subaerial erosion. Shall ow s t r a t a seen on high-resol utionseismic p r o f i l e s appear a s rhythmically interbedded l a y e r s of continuous,horizontal refl e c t o r s between incoherent, poorly refl e c t i v e zones. Thissequence may r e p r e s e n t the low-standlsediment-rich and high-standlsedimentstarved re1 a t i o n s h i p of Pleistocene deposi t i o n .The main s t r u c t u r a l f e a t u r e i n the basin i s the S t . George graben, al a r g e , faul t-bounded depression located north of the No. 1,well. Numerousf a u l t s occur i n the a r e a , mostly along the margin of the graben. These f a u l t sa r e high-angle, down-to-the-basin normal f a u l t s t h a t usual l y c o r r e l a t e w i t hacoustic basement o f f s e t s (Marl ow and Cooper, 1980). Many of the faults r u p t u r ethe near-surface sediments and some c u t the sea f l o o r (Comer, i n p r e s s ) .Surface o f f s e t s of 3 t o 6 feet a r e apparenl on some seismic r e f l e c t i o n p r o f i l e s .Some o f f s e t s may be due to d i f f e r e n t i a l sediment c m p a c t i o n r a t h e r than t orecent t e c t o n i c movement. The area i s seismically a c t i v e , however; Davies(1982 reported three earthquakes i n the range of 6.5 t o 7.5 on the Richters c a l e and numerous smaller events s i n c e 1925. He c a l c u l a t e d a 10 percentp r o b a b i l i t y f o r ground acceleration to exceed 0.2 g a t an a r b i t r a r y site withinthe basin i n a 40-year period.a
The presence o f shal low gas i n the St. George basin i s i n f e r r e d from acousticanomalies oh seismic r e f l e c t i o n p r o f i l e s . These anomalies may be due t o e i t h e rgas-charged sediment o r confined gas accumul ations. Shall ow, gas-chargedsediment i s under normal t o near-normal pressure and poses l e s s o f a r i s k t od r i l ling operations than confined gas accumulations, which may occur i n zonesw i t h abnormal pressure.SITE-SPECIFIC ENVIRONMENTAL EOLOGY-The s i t e survey performed by BBN GeomarineServices Company i n d i c a t e d t h a tt h e sea f l o o r a t t h e w e l l s i t e i s smooth and g e n t l y slopes to the southwest.It i s underlain by f l a t - l y i n g s t r a t a and i s f r e e o f f a u l t i n g . Acousticananal ies on sei smic r e f l e c t i o n p r o f iles suggest the presence o f s h a l l ow gas,and a geotechnical corehole d i d encounter dispersed gas i n t h e sediments from67 t o 236 f e e t below mudltne. This gas was normally pressur
Geological and Operational Summary St. George Basin COST No. 1 We1 1 Bering Sea, Alaska Ronald F. Turner, Editor . INTRODUCTION Ti tl e 30, Code of Federal Regulations (CFR) , paragraph 251.1 4 stipul ates J that geological data and processed geological information obtained from Deep Stratigraphic Test wells drilled on the Outer Continental She1 f (OCS) be made
GEOLOGICAL SURVEY SELECTED GEOLOGICAL SURVEY, U.S. BUREAU OF MINES, AND ALASKA DIVISION OF GEOLOGICAL AND GEOPHYSICAL SURVEYS REPORTS AND MAPS ON ALASKA RELEASED DURING 1978, INDEXED BY QUADRANGLE BY Edward H. Cobb Open-file Report 79-706 1979 This report is preliminary and has not been edited or reviewed for conformity with
hydrogeological and engineering geological mapping) o Detailed geological mapping of the direct area of the route (structural geological, hydro-geological and engineering geological mapping) o Test pits, test shafts and outcrops (exc
Geological mapping is a step-by-step process, which culminates in a compilation of a geological map. Up on completion of the geological map, applied maps of various . to identify geological hazards. 1) IntroductIon to estim
AER/AGS Special Report 101 (October 2015) 1 Introduction K.E. Maccormack1, L.H.Thorleifson2, R.C. Berg3, and H.A.J. Russell4 1 Alberta Geological Survey 2 Minnesota Geological Survey 3 Illinois State Geological Survey 4 Geological Survey of Canada Abstract The objective of this year’s 3D workshop is to
Geological time is vast, and Earth has changed tremendously during this time. Even though most geological processes are very, very slow, the vast amount of time that has passed has allowed for the formation of extraordinary geological features, as shown in Figure 19.1. We have numerous ways of measuring geological time.
Geological Timescale 1 Geological Timescale - for printing and display along a wall Geological timescale background information The geological timescale is one of the major achievements of geoscience over the last two centuries. The timescale subdivides the 4.6 billion years since the planet formed into a series of time units (e.g.
veys reports and maps on Alaska released during 1974, indexed by quadrangle: U.S. Geological Survey Open-file Report 75-128, 46 p. Cobb, E. H., 1976, Geological Survey and selected U.S. Bureau of Mines and Alaska Division of Geological and Geophysical Sur veys reports and maps on Alaska released during 1975: U.S. Geological Survey Open-file .
the coronavirus outbreak - Identify surfaces that are frequently touched and by many people (often common areas), eg handrails, door handles, vehicle door handles (inside and outside), shared equipment etc and specify the frequency and level of cleaning and by whom - Train people how to put on and remove personal protective equipment (PPE) that is used for normal work hazards and how to keep .
