SOCIETY OF PETRCLEUM ENGII’lEERSOF AIME 6200 North Central Expressway &%iR SPE 2562 Dallas, Texas 75206

THIS IS A PREPRINT --- SUBJECT TO CORRECTION

Development of the Offshore East Wilmington Oil Field

By Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021

John N. Truex and William J. Hunter, THUMBS Long Beach Co.

@ Copyright 1969 American Institute of Mining, Metallurgical, and Petroleum Engineers, kc, This paper was prepared for the bbth Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Denver, Colo., Sept. 28-Ott. 1, 1969. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented, Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JCURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office, Such discussion may be presented at the above meeting and, with the paper? may be considered for publication in one of the two SPE magazines.

ABSTRACT 21 miles. The Ranger Petroleum Co., Well No. “Watson” 2, completed January 26, The East Wilmington Oil Field, 1932, for 150 barrels per day of 14 degree comprisinci approximately 5930 productive gravity oil was the first conntercialwell acres, is located just off-shore Long completed in the field. However, recog- Beach, California, and contains oil reserves nition and development of the Wilmington of approximately 800 million barrels. structure awaited the completion of It is being developed by THUMS Long General Petroleum Corporation, Well No. Beach Company as contractor for the ‘:Terminal!!1 , in December, 1936, for City of Long Beach, the Unit Operator. 1419 barrels per day of 20.5 degree gra- Development is from four, 10 acre, vity oil. Rapid development followed man-made islands and two on-shore this event, and prior to initial drilling locations. Approximately 575 wells in the Long Beach Unit in July, 1965, have been drilled to date, producing approximately 3500 wells had been drilled from eight zones. Cumulative oil and had produced about one billion barrels production as of June 30, 1969 was of oil from 7825 acres. 93,485,157 barrels. Subsidence began in the center of HISTORICAL BACKGROUND the field shortly after iiiceptiofiof production, and rapidly became a major The East Wilmington oil field is problem. Pilot water injection was located in the south central part of initiated in Fault Block VB in the Upper the Los Angeles basin, on the south- Terminal zone in June, 1953, and was easterly plunge of the Wilmington quickly extended to other zones and fault anticline (Plate 1), The Wilmington blocks. In 1956, the City of Long Beach oil field overlies a basement high prohibited drilling east of Pine Avenue that extends in a southeasterly direct- until the subsidence was controlled, the ion from Torrance oil field to Hunt- excluded area including all the present ington Beach oil field, a distance of Long Beach Unit, exclusive of Tract 2. The success of the early pilot floods, References and illustratlons at both in the local arresting of subsidence end of paper. and in secondary recovery, led to the creation of four fault block Unit Agree- The Long Beach Unit contains 6700 acres ments between January, 1959 and April, of which approximately 5930 are productive. 1964, providing for water injection in The Unit is divided into: Tract 1, the the various zonesl. This injection Long Beach Tideland area; Tract 2, the program has successfully arrested sub- Alamitos Beach State Park; and Tracts 3 to sidence in the older Wilmington area. 91, the townlot area. The total Unit is now estimated to contain approximately 870 The City of Long Beach conducted million barrels of recoverable oil. an off-shore seismic survey in 1954, extending southeasterly from the then STRUCTURE legal limit of production at the Parcel A boundary. This survey estab- The broad Wilmington anticline plunges lished the southeasterly continuation southeasterly across the entire Long Beach of the Wilmington anticline for at Unit. In the vicinity of islands Bravo Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021 least four miles to the Orange County and Delta, the Junipero and Long Beach Unit line. faults produce local flattening of dip and change of strike, but the regional plunge The voters of the City of Long is uninterrupted (Plates 2 and 3). The Beach lifted the ban on off-shore anticline is asynlnetricai, with beds on K-kwtawv 27, +ha en~~~ f?~~~ ~innin drilling by referendum m rculualy bllG au .Vy.m.g = steeply as 60 1962. Shortly thereafter, the City degrees, while the maximum dip on the north of Long Beach drilled eight off-shore flank is about 20 degrees. Below the top core holes to verify the structure and of the Ranger zone, the axial plane of the the productive limits of the different anticline shows little or no migration zones. Based on the results of these with depth. core holes, the Department of Oil Properties staff reinterpreted the At least eleven faults with displace- seismic survey, and originated a com- ments in excess of 40 feet have been prehensive study for the development recognized in the Long Beach Unit. The and exploitation of the off-shore area. largest of these and the largest in the entire Wilmington field is the Long Beach In early 1964, the City of Long Unit fault with a displacement of 100 feet Beach, the upland property owners and on the north flank, increasing to about the townlot operators concluded a Unit 600 feet on the south. Approximately 2000 Agreement for the operation of the feet of right lateral movem nt is found on eastern area. A Field Contractor’s this fault. Moody and Hill!!describe the Agreement was prepared, under which the Wilmington anticline as a second order drillin~ and production operations would drag fold resulting from movement on the be carried out for the Unit under City Inglewood fault zone. The average strike direction. After extensive hearings, and the right lateral movement of the Long the California State Lands Commission Beach Unit fault conform to Moody and approved both the Unit Agreement and Hills’ definition of a second order wrench the Field Contractor’s Agreement late in fault. 1964. Bids were called for by the City in early 1965 to select the Field Con- All Wilmington field faults are of tractor for the Unit. THUMS Long Beach the normal or wrench type, cutting the Company was the successful bidder, axis of the anticline at angles of 30 to offering 95.56 per cent of the net 45 degrees, with the strike usually being profits plus a ten million dollar bonus, found in the NW-SE quadrants. 17 million dollars in advance royalty payments in the first year, and one A major change in oil-water contacts million dollars a month thereafter until of all zones is found across the Long Beach payout. The Field Contractor receives Unit fault, and minor to major changes are three per cent of Unit expenses as over- associated with the other recognized head. THUMS was a newly created company faults. Detailed interpretation of the owned equally by Texaco Incorporated, faulting east of the Belmont B-1 fault Humble Oil and Refining Company, Union and north of the C-608 fault has not been Oil Company, Mobil Oil Corporation, and satisfactorily resolved. Significant Shell Oil Company. The first well in differences in the Tar, Ranger, and Upper the new unit, J-145, was completed from Terminal zone limits are known in this PierJ in August, 1965. This well has area, apparently related to faulting of subsequently produced 849,000 barrels of such small displacement as to be unrecog- oil. nizable in electric log correlation of the ;PE-2562 JOHN N. TRUEX and IILLIAM J. HUNTER 2

highly directional wells. of marly shell up to one foot thick. Middle of interval never completely STRATIGRAPHY oil saturated. (4) Lower Terminal zone, 750-800 feet The age of the producing formations thick, Delmontian in age. Sands are found within the Long Beach Unit ranges similar to the Upper Terminal, but from questionable Jurassic for the somewhat coarser and more massive, Catalina schist basement to Lower becoming firmer in the lower portion. e.--.!+..KIS L Pliocene, Repetto, for the Tar zone. ur-ey w UIaCh, wallWGI , +ndliva+cad,ll-W,-----

well laminated and locally with the Catalina Franciscan ~?~\.! diatomaceous in the lower part. schist. Bluish or greenish, fractured, Occasional thin beds of hard, marly glaucophane schist, with common quartz ~llel..h111. and calcite veinlets. Combined with (3 Upper Terminal zone, 700-750 feet the nodular shale to form the D-ii8 thick, Delmontian in acie (Upper sub-zone. Miocene). Soft to eas~ly-friable, silty, fine- to medium-grained, Plate 4 gives the net oil sand thickness fairly well sorted, arkosic sands and productive acres for the various zones. with grey to black siltstone and All zones except the Tar thicken between laminated shale, Occasional beds the old Wilmington field and the Long Beach DEVELOPMENT OF THE OFFSHORE EAST WILMINGTON OIL FIELD SPE-256

Unit. The fractured nodular shale of the oil, and gas lines are buried beneath the D-118 sub-zone is either missing or non- ocean floor, and connect the four islands productive in the old developed area. with Pier J. The Ranger zone is by far the largest, both in reserves and areal extent All personel and equipment are trans- (Plate 5). ported to the islands by a fleet of crew boats, tugs, and barges, operated under SPACING contract to THUMS. Equipment and supplies are stored in a warehouse on Pier G, where The preliminary spacing plan for the two barge ramps are located for loading and Long Beach Unit was developed by a unloading material and equipment. sophisticated computer model, using m------E ALA 1 ..:.+4-. m-nhl m TMIIMK parameters that were modified from known ~e~dUS~ UT bll~ loyl>Llb> pruulf%ll$ IIIUI@ data in the older developed portion of has installed a data transmission system Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021 the field (Plate 6). After drilling utilizing telephone lines. Units capable comnenced in the Long Beach Unit, of sending and receiving are installed on additional runs were made utilizing each island, at the Pier G production data obtained from the new wells. Since office, in the City of Long Beach Harbor drilling is now almost completed, no major Department building, and in the Development additional spacing plan modifications Engineering section in the main office. appear necessary. Drilling programs, field memorandums, survey results, and most important, wire- Spacing for all the zones is line logs can be sent over this system, variable, ranging from about six acres with a resultant saving in time and man- in crestal locations to 40 acres on power. the flanks. Well locations were determined by the estimated productivity and oil in Directional Drilling Control and place, and therefore vary, depending on Problems Involved the structural position and fault block. Almost all the wells in the Long Beach The latest -r..-soacina...dplan calls for Unit are directionally drilled (Plate 7). 680 wells, including 505 producers and A large number of wells have hole angles in 175 injectors. However, this number excess of 60 degrees from the vertical and is subject to revision as more production several exceed 75 degrees. Initially, and injection data are obtained. whipstocks were used for directional control, but due to inherent disadvantages, DRILLING AND COMPLETION TECHNIQUES they have been replaced by down hole mud motors and the Rebel tool which have proven Initial drilling was from four very successful. Maximum programmed build- sites on Pier J, an earth-filled up is limited to 5 degrees per 100 feet, extension in the Long Beach harbor, and drop-off to 2-1/2 degrees per 100 feet. which abuts the Long Beach Unit on the Single shot surveying instruments are used west. Conventional portable diesel for drilling control, with drop-type rotary rigs were used, and trans- multiple shot instruments run at surface portation and servicing of wells were casing point, water string setting point, simple. The four, 10 acre islands and at total depth. The multiple shot is constructed in the harbor presented considered the “official” survey of the some problems in logistics. On hole, and is used for calculating all islands Alfa, Bravo, and Charlie geologic markers. Both single shot and (now named Grissom, White, and Chaffee) multiple shot stations are taken every four all-electric rigs were designed 30 feet * during build-up portions of the and built to THUMS specifications. hole, and every 90 feet * during the The masts were built to resemble high- remainder of the drilling. Single shot ~i~e apal-.--.m+mam+.I.IIICIIK.~~ nnd,l.-n1GUUW !l~~~~~~~ stations are reread b~ya THUMS employee present an attractive app.sarzncewhen to verify the directional company”’s results. viewed from the shoreline. Extensi%{e They are then run through a computer landscaping and free-form sculptural p~~grqm viaoa remote terminal in the designs were zddeG to disguise the bu~ldlng, tied to a master computer. driiling and production operations. Multiple shot stations are read by the Due to the distance from Shoine, island service company, and are reread by a Delta (now named Freeman) was able to THUMS engineer or geologist only when large utilize six conventional diesel rotary discrepancies are noted compared to the rigs; landscaping was keqt to a single shot. The service company provides minimum. Al? elect~;cal power, wate;”, THUMS with a complete calculated survey, >E.2562 JOHN N. TRUEX and ILLIAM J. HUNTER 5

The final surveys are then run through (9) Location of survey stations. THUMS’ computer program for permanent storage, and geological markers and The data derived from the current other survey data output are machine methods of surveying directional holes calculated at the same time. are probably the weakest link in sub- surface geological interpretation. Some Initial methods for calculating geologists in the area have adopted the points were done by the tangential, “purist” approach - ie., honoring all terminal angle method, which was the control points without regard to the above procedure in general use in the area. mentioned errors. This presents many The terminal angle method assumes that problems when dealing with oil-water the drift angle (or bearing) changes contacts, since even small contact abruptly at the top of the course differences in adjacent wells (10 to 20 feet) must be explained by faulting, length and maintains the terminal Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021 angle drift (or bearing) for the entire permeability barriers, or tilted water course to be calculated, a condition tables. This in turn tends to indicate obviously seldom encountered. It geologic conditions which probably do not was decided to use the average angle exist, and could possibly lead to method for calculating vertical depth erroneous reservoir interpretations and and direction (Plate 8). The average the drilling of unnecessary wells. angle method assumes that the average G. J. Wilson3 encountered similar problems drift angle (or bearing) for the with directional surveys and presented his course to be calculated is the average own solution. THUMS geological staff, of the drift angles (or bearings) at aware of the inaccuracies present when the top and bottom of the course. working with deviated wells, uses the This method removes much of the error “averaging” approach in constructing maps inherent in the terminal angle method. and cross-sections. Questionable points The main disadvantage encountered is are simply not honored when adequate in tying control points calculated by evidence is present to justify their the one method with points calculated exclusion. by the other. Plate 9 shows an actual well course in section view calculated Types of Wireline Logs and Problems by both methods. Encountered by High Hole Angles

Even with the improved technique, Early in the development of the it must be realized that vertical Long Beach Unit, it was found that depths between adjacent control points conventional wireline logging tools can vary by as much as 20 to 25 feet, would not go down many of the wells due to one or more of the following because of the high hole angles. Below factors: 60 degrees in open hole, most conventional (1) Differences in hole angles between logging tools will go, provided great care adjacent wells (high angle hole is made to condition the hole and mud next to a low angle hole, or one adequately. Above 60 degrees hole angle, weii dropping angle through zone the novcentaaer-. --..--=- of- “no-gos” increases next to one holding constant angle). greatly, and above 65 degrees very few (2) Bearing of well course; magnetic tools will go. In cased hole, logging influence of the drilling string sondes have occasionally gone in 72 is greatest in the East and West degree angle holes. Because many wells directions. have drift angles in excess of 60 degrees, (3) Errors in wireline and/or dri11 it is necessary to run small diameter pipe measurements. (2-3/8 inch) sondes, and pump the tool (4) Lack of proper alignment between through the drill pipe. The general surveying instrument and drill procedure is to run open-end drill pipe pipe, and drill pipe and hole. to a point a few hundred feet above the (5) “Hot” (magnetized) drill collars top of the zone, and pump the sonde and/or drill pipe. through the pipe with the mud pumps. (6) Local magnetic anomalies, The pumps are shut off just prior to the including down-hole motors, sonde going out the end of the pipe, and casing, tubing, etc. usually the tool will fall to bottom un- (7) Skil1 and technique of the operator aided. Most of the wells are drilled in reading the shots. an “S” shape, and generally the drill (8) Unreported accidental dropping of pipe can be hung at a point where the survey instruments, affecting drop-off has started. Where a log of the calibration. entire hole is needed, it is often necessary to run it in 90 foot segments. is extremely important, since sand L&ill pipe is run to a point just below counting is based primarily on the SP, the previously logged segment; the sonde combined with certain res~st~vity values, is pumped out the end of the pipe (usually and Unit equities are determined from the stopping there), the pipe is pulled up a sand counts. Difficulty was encountered stand, and the hol~ is logged up to the in logging wells on Pier J, particularly end of the pipe. The sonde is then on certain drill sites. It was often pulled out of the hole, a stand stood necessary to relog the hole several times back, and the process repeated. There in order to get an SP curve that would have been as many as 35 separate runs meet THUMS standards. Mud properties made by this method in order to obtain were often unsatisfactory, and logging a log of the entire hole. The upper crews were unfamiliar with the high angle part, from kick-off point to maximum holes. Stray electrical currents were

hole angle, is usually logged with a frequently encountered, and it was Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021 conventional sonde. occasionally necessary to shut off all motors in the vicinity of the well in At the start of drilling order to obtain a satisfactory log. operations in the Long Beach Unit, the Equipment malfunctions were common, and only logging tools small enough to go many man hours were spent in order to T..:+.iall,lfirIinn through 4-1/2 inch drill pipe were , obtain quality lags. Irllblallj, IUyg,.,= conventional Electric log sonde and L problems were common on the islands, but Ganma Ray-Neutron. Because of the because of the strict log quality control need for quality logs, small diameter procedures, logging problems are now Induction-Electric log sondes were infrequent. developed by the major logging companies, which enabled THUMS to CORING TECHNIQUES obtain either an Induction-Electric or Induction-Gamma Ray log in all The Unit Agreement specifies that wells, regardless of the hole angle. each of the productive zones in Tracts 1 and 2 must have one full-zone core . +h#. Ll+lmi LO”rrel~tiOilS lfi Lrfc WI Illllngton for each 320 acres, and the townlot area field are generally quite good, and an must have one full-zone core for each Induction-Electric log is the only log 160 acres. The reservoir information run in most wells. Auxiliary logs are obtained from the cores is used for generally run only for specific determining and assigning equities among reservoir information, and include: the various participants in the Unit. -,-~- .---..2----A hsc Ganma Ray-Neutron, Pulsed Neutron, lnls r-tXpIII-Cikllb Ilaa n=u==alaenccitatd ---- an Acoustic, Density, and occasionally extensive coring program, and over the Microfocused log. In wells that 45,866 feet of core have been cut as of are cored for equity purposes, an July 1, 1969, with an average recovery Acoustic, a Density, and a Gamma Ray- of 86 per cent. Because of the importance Neutron are run in addition to the of this program, rigid and thorough Induction-Electric (Induction-Ganma supervision is necessary. Each core must Ray). In these wells, the suite of be met by a THUMS geologist, and because logs is run through a special computer of transportation problems and the speed program to give calculated porosity with which cores are cut (especially in and water saturation values. Porosity the Ranger zone) four men are needed full- values obtained from both the Acoustic time when two or more wells are coring at and Density logs are in good agreement the same time (which is often the case). with core-derived values in the Union In the four upper zones, 30 foot cores are Pacific and Ford zones, but in the cut using a drag type core head. In the upper zones log porosities are deeper zones a 60 foot core barrel is used generally lower than core porosities. utilizing a diamond core head. Core bits Due to the unconsolidated nature of are either 7-5/8 inch or 8-1/2 inch the sands in the upper zones, cycle- diameter, and core barrels are 3-1/2 inch skipping is a problem with the or 4-1/2 inch diameter. After the Acoustic log, and the Density log is geologist has tagged, measured, and more reliable. described the core, samples are taken every two feet of sand by a representative of the Because of adverse hole conditions laboratory cio~iigthe ecre zm?ys!s. The and the difficulty in obtaining good cores are then transported to permanent Spontaneous Potential values, it storage facilities on shore. A few rubber became necessary to initiate strict log sleeve cores have been taken, but it was quality control procedures. The SP curve felt that the time and cost involved was not ‘E-2562 JOHN N. TRUEX and ILLIAM J. HUNTER

justified. zone (depth varies depending on angle of hole and structural position - CORE ANALYSIS PROCEDURE usually 2500 to 5000 feet), and run multiple shot survey: Because the consolidation of the 6. Run InductionTElectrlc log. sands varies from loose to very hard, 7. Cement $3-5/8 Inch, -.27 nv., ~c !!),, J-55> two methods of core analysis are used 8-rd thread Buttress casing with API bv THUMS: Class “G” cement and pozzalan admix. (1) Soft, unconsolidated sands. Cement to fill to 50 feet above base The sand sample is encased in a of fresh waters. 1-1/4 inch long x 1 inch diameter 8. Run Water shut-off test (a requirement lead sheath, and the ends are of the State of California). covered by 120 mesh screen using 9. Drill 7-5/8 inch hole to total depth a pressure of 350 psi. Saturations and run multiple shot survey. are determined using the distillation 10. Run Induction-Electric log. Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021 method. For determining porosity, 11. Change over to completion fluid and the helium porosimeter is used, and wall-scrape 7-5/8 inch hole to 8-112 permeabilities obtained are air inches and 14 inches. permeabilities. 90 psi is applied 12. Run Caliper log. to the sample during analyzing. 130 Hang 6-5/8 inch, 28 lb., 8-rd thread (2) Harder consolidated sands. T & C and flush joint shop perforated Plugs are cut or drilled out, and liner (24-2-6-60.)fitted with measure about 1 inch long x 1 inch external casing packer assemblies. diameter. No mounting or compact- 14. Set, test, and cement k,.,c~n external ing is necessary. A down-draft casing packers. retort is used to obtain saturations. 15. Gravel flow-pack 6-5/8 inch x 14 inch Porosity is measured by the gas annulus with” 6-9 Tyler Mesh gravel. ~xpan~ion nroces~~.--_– usina a Kobe 16. Displace completion fluid with NaL”l- porosimeter. Permeabi~ity values caCi2 brine, and w~sh ml repack 8s are air permeabilities. necessary for gravel fillup. A sample is also taken every 10 feet 17. Run hvdraulic or submersible pump on of sand, wrapped in foil, dipped in tubin~ and place well on production. plastic, and stored for future use. This program applies to the Tar, RESERVOIR CHARACTERISTICS Ranger, Upper and Lower Terminal zones. For Union Pacific and Ford zone wells, Average permeability and porosity the water string is 9-5/8 inch, 36 and values for the various zones derived 40 lb., J-55 and N-80. Liner hole is from core analysis are tabulated below: 8-1/2 inch, and 6-5/8 inch, 28 lb., Oi1 slotted liner is hung with two or more Zone sets of external casing packers. These Tar W-* wells are not gravel packed. Some wells Ranger 33.76% 1088 md. 17.9° have blank liner cemented through zone Upper Term. 37.2 % 1188 md. 19.1° and jet perforated. Lower Term. 33.82% 584 md. 20.3° Union Pacific 24.29% 148.5 md. 28.4° Early in the development program it Ford 21.10% 159.5 md. 28.4° became obvious that a good method of zona” segregation was needed. Since the upper four zones require gravel packing to DRILLING AND COMPLETION PRACTICES control sand entry, it is not possible to cement blank liner and selectively per- A typical drilling and completion forate. putting biank iiner opposite wet program for an upper zone well is as sands or segreg~tion points and-attempting follows: to cement behind the blank interval has ?. Drill 12-1/4 inch hole to 950 feet never been satisfactory under ideal (20 inch conductor previously set conditions, and in high angle holes it is at 90 feet *) using clay-water mud. even less successful. It was decided to 2. Run multiple shot survey. try the inflatable external casing packer 3. Open 12-1/4 inch hole to 18-1/2 that could be made up as part of the liner inches, and cement 13-3/8 inch, assembly, expanded against a reduced 48 lb., !-!-40,~L!ttWSS thread portion of the liner hole, and be used to casing with returns to surface. Isolate wet sands and separate subzoaes 4. Install and test B.O.P.E. to enable better control for injection and 5. Drill 12-1/4 inch hole to top of production. This method has proven so — nc!fclnntdr~m nr TUE nrccunDc FAST wTlfvITN~Tf)N OTL FIELD -r .- . . . --- . . . .- -. . ------SPE-256;-. — -.

successful that practically all wells have raised south flank pressures to their from one to four sets of packers. As present level. (d) Leakage along faults added insurance, cement is placed between in the geologic past lowered original each set of packers. Plate 10 shows a pressures below hydrostatic. South flank typical packer installation. pressures were subsequently increased by the mechanism employed in (c). The true In order to obtain a satisfactory explanation may involve a combination of pack, it is desirable to have a drift these factors. angle of less than 50 degrees in the liner hole. On long drift wells this The reduction of pressures on the requires an “S” shaped curve to the north flank has resulted in gas coming well course, with the maximum angle out of solution, and the consequent production of much free gas with the oil. obtained at approximately 1500 feet to Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021 allow dropping angle to less than 50 To conserve reservoir energy, wells with degrees at casing point. In some long gas-oil ratios in excess of 2000 cubic drift aquifer injectors where drift feet per barrel of oil are shut-in. Water angle cannot be dropped low enough, injection in the aquifer is expected to shop pre-packed 5-1/2 inch liner is eventually increase reservoir pressure to run. External casing packers are run on the point where most of the gas may return ,-..-..2---~ *l__--- -:7 --A:- the iiner and used for zonal segregation. to solution. Lowering CJT me ya5-uI I rdI.Iu Generally, two sets are run, permitting to the point at which the well could be separation into three subzones. returned to production has already been observed in some of the previously shut-in The Union Pacific and Ford zones’ wells. sands are firm and well consolidated and do not require sand control Numerous individual water tables are measures. However, external casing found in all zones. Within the Ranger packers are run in these wells for and Ford zones, the sands go wet at the zonal segregation. bottom first, and the higher sands have the greatest productive areal extent. The lower 237 and Basement zones’ The Upper and Lower Terminal zones have wells are completed in a similar manner intermediate sands which go wet before to the Union Pacific and Ford zones’ those above and below them, and these wells. must be segregated by external casing packers. To date, three separate water RESERVOIR PROBLEMS table depths are recognized in the Tar zone, eleven in the Ranger, fourteen in From the inception of production the Upper Terminal, nine in the Lower in the Unit, reservoir pressures in Terminal, nine in the Union Pacific, ten the Ranger zone on the north flank in the Ford, and one each in the 237 and were found to be as low as 70 per cent Basement zones, for a total of 58. Oil- of hydrostatic, both east and west of water contacts in individual sands vary the Long Beach Unit fault. Pressures in different fault blocks. West of the on the south flank were 95 per cent Long Beach Unit fault, the Ranger zone hydrostatic to hydrostatic. The lower has an approximate 4000 foot oil-water pressures observed on the north flank contact in the “F” to “X” interval. Oil- have been attributed to: (a) voidage water contacts east of the fault are by production from the old part of the higher than those to the west by the Wilmington field, or (b) voidage by approximate throw of the fault. Faulting I production from t e Long Beach and after migration is implied. !! , Seal Beach fields , located about one t mile north of the north flank oil- WATER INJECTION water contact. Both explanations require rapid pressure communication The Unit Agreement, under which through or around known faults. The THUMS as the Field Contractor must authors suggest the following additional operate, requires that water be injected explanations: (c) original pressures into all unitized formations from the were never at hydrostatic. The initiation of production. The primary observed pressures are partially fossil, objective of the injection program is to and have been depressed below their prevent a recurrence of the subsidence original elevation. A semi-active problem which originally plagued the water drive observed on the south Wilmington field. As a direct result of flank combined with .aquifer injection the early initiation of water injection, from the old part of the field has the field has been under a Pressure main-

— DC–9KCII JOHN N. TRUEX and WILLIAN J. HUNTER 9 per day. tenance program almost from the inception of production, with no true primary phase. PRODUCTION Water flooding by aquifer injection is employed in all zones except the Ranger The Long Beach Unit is currently and D-118 zones. A staggered line drive producing 145,000 to 150,000 barrels per flood employing both in-zone and aquifer day of oil and 65,000 barrels per day of injection is used in the Ranger zone. water from 433 wells, together with Production from the Basement zone is approximately 55,000 MCF of gas. There from fractured, very dense shale and are 41 wells currently shut-in, mostly schist. As it poses no threat of due to high gas-oil ratio. The revised subsidence, the zone is not being maximum daily production forecast is flooded at present. 156,000 barrels per day (Plate 11). Cumulative oil production as of June 30, The progress of the flood is 1969 was 93,485,157 barrels of oil. Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021 followed by spinner surveys in the injection wells. Segregation of groups of sands by external casing REFERENCES packers permit the sleeving of intervals which are receiving excessive 1. Mayuga, M. N.: “Geology and Development water. The future progress of the flood of California’s Giant - The Wilmington will be followed by the change in Oil Field”, Department of Oil Properties, electric log properties of logs in re- City of Long Beach, California, (1968), -J..211-J ..-71- m-l h . en~nnaw ~g~vevc arllleu weII>, ZiIIU Uj ~plllll=l A-~a and other types of water entry surv& 2. Moody, J. D., and Hill, M. J.: “Wrench- in producing wells. Much of the future Faul~”Tecton{cs”, Geol. Sot. Amer. Bull., geological work in the field will Vol. 67, 1218-1219. involve the following of the advancing 3. Wilson, G. J.: “An Improved Method for flood fronts in the various zones. The Computing Directional Surveys”, Trans. water has already shown a preferential AIME, (1968), Vol. 243, 871. breakthrough in the sands of lower 4. James, D. M., Mayer, E. H., and pressure and higher permeability, and Scranton, J. M.: “Use of Economic and many wells nearest to the injection Reservoir Models in Planning the Ranger rows will require early abandonment Zone Flood, Long Beach Unit, Wilmington or extensive remedial action. Field”, SPE, No. 1855, Presented at 42nd Annual Fal1 Meeting, (Ott. 1967). A ratio of one injection well for 5. Szasz, S. E., Fantozzi, J. H., and every three producing wells is main- Adent, W. A.: “Development of Long tained in the Ranger zone. Sufficient Beach Unit in Offshore Part of water will be injected to replace Wilmington Field”, Am. Assoc, Petroleum, reservoir voidage and maintain reservoir Geologists Bull., Vol. 53/2, (Feb. 1969 pressure. 458 (abstract). 6. Crippen, R. G., and Wright, A. C.: The current daily rate of water “Procedures and Techniques Employed in injection into all zones is approximately Logging and Evaluating High Angle Well 400,000 barrels per day from 97 injection Bores on a Large Scale Driiiing and wells. The maximum daily rate of water Development Program”, Trans. SPWLA injection anticipated is 500,000 barrels Ninth Annual Logging S-ium, (1968). Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021

PEDRO \ \ 0- “LES GRAPHIC

“N ,000 0 ,000 2 , k-m

Plate 2 - Ranger zone.

A A’ .,,, cm!

/ _— _

-4000–

-s000 237

v v WVV

Plate 3 - Long Beach Unit cross section. Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021 II 10NG.BEAU u!!!!! II GROSS NET O I L ACRE PROD. STAiGE ZONE THICKF~ SAND FT. ACRES —1 TAR 200’-400’ 50’-95’ 71,635 2871 BIPilTTIAIN RANGER 400’-700’ 220’-420’ 1,465,412 5931 – U. TERMINAL 700’-750’ 400’-500’ 244,243 1469 D?,LIIONTIAN L TERMINAL 750’-800’ 445’ 86,044 509 UNION PACIFIC 900’-9’50’ 230’-285’ 172,127 I325 - “PPBB FORD 95o’- IZOO’ 500’-600’ 323,304 1418 MOKNIANI — — LOWEn MOHNIAN 237 ‘ 2650’ 75’ _ — 1,#;o~q;~~A~ 8ASEMENT —– — — *I NCLUOES D-118 ZONE --—

Plate 4

Plate 5

‘o’ Y \ coNTOl-lRsON “F” MARKER w \ DEVIATION

Plate 6 Plate 7 - THUMBS Long Beach Unit 540 >-:,1-.I ....-.17-.= .-.+ ril 1 196!? ‘1

Station-l do. ~R 3000 Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/69FM/All-69FM/SPE-2562-MS/2069540/spe-2562-ms.pdf by guest on 02 October 2021 ,l:F&:E I “\ Iwo’ \ \ ~ \ x.,

\ \ - —JF—1603’ ~------2l5.4------1620’—-J >\>\ ~_ -–––222,6––––––J K l?W-KF --\ ——KF—1752’ !>

Plate 8 - Comparison of methods of calculating surveys by terminal angle and average angle.

2302’— s ––-—~~—S–2284’ 2560k-d%===,—fo ———~ 28!08’—H ——— H—2791’ X—2634 TTil ~ 2910’— X ——— 1,1,1,1 TYPICAL 1,1,(,; 3oco– PACKER 3069’— G ——— G — 3053’ 1,1,1, YT- INSTALLATION i,_, I I o l.-, @(jJl, r z~,ll. Jo’ ‘ -’ .=.. =4.–..- l+-- /4=HoLE —. I Plate 9 - Comparison of multishot surveys —8%”HOLE calculated by terminal and average angle PACKER methods. Vertical depths shown on both methods. SErBYXWMf’ 112 —.t“ Pmssum -PACKING ELEMEW

r 7%”(2A 200,000 200,000 L — FORT COLLAR ~:? i 4 RIG~[&@ 7i __—_ ———— – 160,000 1160,000- ——-—- -—-– -- o 1

-120,000 1120,000 --——- --— R -:.:1 GROSS DID 011 BID -80,000 k% - PRLSSU/?E 80,000 –- ‘1 o * - 40,000 j 40,000 - GAS MCF/D

d 1,1,1’1 1,1,1, o 1969 0 1,1,1, _ 1965 1966 _~67 1968

IF Plate 11 - THUMBS Lolng Beach unit ptouuction. plate 10 - Typical packer installation”