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Home My WebLink About1988 Initiation Waterflood Endicott Oil PoolStandard Alaska PFOEm aCopany R�0 Eo .,t sl Benson Boulevard P.O. Be. 196612 Anchorage, Alaska 99519-6612 190)) 5615111 June 2, 1988 Chad V. Chatterton, Chairman Alaska Oil and Gas Conservation Commission 3001 Porcupine Drive Anchorage, Alaska 99501 Dear Mr. Chatterton: STANDARD ALASKA PRODUCTION S? GEOL �R (3EOL NG ASST :NGAS7 —1— ;TAT TFrHi -ILE: RE: Implementation of Field -Wide Waterflood in the Endicott Pool As discussed in our meeting of May 19, 1988, we request approval of our plans to initiate a field -wide waterflood in the Endicott Field, as set forth in Conservation Order 202, rule 12. Significant pressure decline observed in the southeast section of the field indicates pressure isolation from the main part of the reservoir. This rate of pressure decline accelerates the implementation of full scale waterflooding in this region. The waterflood plans for this region are to drill and complete two injection wells in each of the three major sub -zones before the end of this year. Additional reservoir studies in conjunction with observed field performance will determine if additional injectors will be needed for improved reservoir sweep. In the main part of the field the reinjection of produced gas into the gas cap is providing good pressure support. We plan to further evaluate reservoir performance before determining the extent of waterflood operations in this section of the field. Final waterflooding plans for this area will be finalized next year. Due to the nature of the observed field performance and the need to react in a timely manner, we can not give you complete waterflood development plans at this time. As discussed, we will periodically submit updated reports to you as these plans are finalized. Additionally, well conversions will be reviewed by the AOGCC when approval is requested by the appropriate sundries notices. RECEIVED JUN 10 1988 2120A Alaska 011 & Gas Oona. pommissur GRA: slb Anchorage A unit of the original Standard Oil Company Founded in Cle.elmd. Ohio, in 1870. (too COA"'M COMW l ror.ir'n Chad V. Chatterton, Chairman Alaska Oil and Gas Conservation Commission 3001 Porcupine Drive Anchorage, Alaska 99501 Dear Mr. Chatterton: STANDARD ALASKA PRODUCTION S? GEOL �R (3EOL NG ASST :NGAS7 —1— ;TAT TFrHi -ILE: RE: Implementation of Field -Wide Waterflood in the Endicott Pool As discussed in our meeting of May 19, 1988, we request approval of our plans to initiate a field -wide waterflood in the Endicott Field, as set forth in Conservation Order 202, rule 12. Significant pressure decline observed in the southeast section of the field indicates pressure isolation from the main part of the reservoir. This rate of pressure decline accelerates the implementation of full scale waterflooding in this region. The waterflood plans for this region are to drill and complete two injection wells in each of the three major sub -zones before the end of this year. Additional reservoir studies in conjunction with observed field performance will determine if additional injectors will be needed for improved reservoir sweep. In the main part of the field the reinjection of produced gas into the gas cap is providing good pressure support. We plan to further evaluate reservoir performance before determining the extent of waterflood operations in this section of the field. Final waterflooding plans for this area will be finalized next year. Due to the nature of the observed field performance and the need to react in a timely manner, we can not give you complete waterflood development plans at this time. As discussed, we will periodically submit updated reports to you as these plans are finalized. Additionally, well conversions will be reviewed by the AOGCC when approval is requested by the appropriate sundries notices. RECEIVED JUN 10 1988 2120A Alaska 011 & Gas Oona. pommissur GRA: slb Anchorage A unit of the original Standard Oil Company Founded in Cle.elmd. Ohio, in 1870. Chad,V. Chatterson, Chairman June 2, 1988 Page Two If you have any questions or comments, please contact Mr. Gary Adamson at 564-4624. In the interim, we request your approval to add up to two additional pilot injectors prior to the initiation of the full field waterflood. These wells will be added in the southeast section of the field where we have observed the rapid pressure decline. Sincerely, J. W. Buckee Vice President, Development Planning cc: Working Interest Owners RECEIVED JUN 10 1988 Alaska Oil & Gas Cons. Commission Anchorage 2120A GRA:slb WATERFLOOD PLANS A PILOT WATERFLOOD WILL BE IMPLEMENTED IN MARCH 1988. INJECTION WILL BE INTO THE BETTER DELINEATED ZONES 2A, 2B, AND 3A. THE PRIMARY OBJECTIVE WILL BE TO ENHANCE THE IMPLEMENTATION OF THE FULL FIELD WATERFLOOD. THE PILOT WILL BE EXPANDED DURING 1989 TO PROVIDE VOIDAGE REPLACEMENT FOR THE FIELD IN ZONES 2A, 2B, AND 3A. EXACT TIMING AND WELL LOCATIONS IS CONTINGENT ON RESERVOIR PRODUCTION/PRESSURE PERFORMANCE. PLANNING FOR EXPANSION OF THE WATERFLOOD INTO ZONES 3B AND 3C WILL REQUIRE INFORMATION OBTAINED AS DELINEATION OF THESE ZONES OCCURS IN 1988 AND 1989. ADDITIONAL WELLS WILL BE ADDED AT LATER TIMES AS REQUIRED TO IMPROVE SWEEP EFFICIENCY AND MAINTAIN LOCALIZED VOIDAGE REPLACEMENT. TIMING AND PLACEMENT OF THESE WELLS IS AGAIN DEPENDENT ON RESERVOIR PERFORMANCE. WATERFLOOD -- FIELD RULES NO INFORMATION GATHERED TO DATE DURING THE DEVELOPMENT AND EARLY PRODUCTION PHASE OF THE FIELD WOULD MATERIALLY AFFECT OR LEAD TO ANY VARIANCE OF THE FINDINGS OF THE FIELD RULES HEARING WITH REGARD TO WATERFLOODING. FIELD RULES 12 a) A field -wide waterflood project is approved for the pool area. 12 b) The field waterflood project must be started within two years after regular production from the pool has started. 12 c) The waterflood plan will be submitted to the Commission at least three months before actual water injection begins. 12 d) All applications for permits necessary to implement the waterflood project shall be timely submitted for approval. 11 b) A program to monitor well productivity and injectivity will be submitted to the commission for approval at least three months before water injection begins. WATERFLOOD PILOT SINGLE WELL INJECTION IN EACH OF 3 MAIN SUBZONES -- 2A, 2B, 3A Injection will be into the lower section of the light oil column and the aquifer above the tar zone. Injection into the aquifer below the tar zone is being considered if an opportune place can be found PILOT OBJECTIVES Determine well/subzone injectivities Determine pressure response to water injection Evaluate sand continuity and fault communications Establish and test a tracer program Evaluate water injection control of gas cap advancement Identify thief zones Obtain early indications of breakthrough performance Shake down waterflood equipment WELL SELECTION Sag Delta 10 is planned as a 2A injector. Final selection of other wells depends on drilling results. Other potential injectors are P-14, P-24, or Q-28. INJECTION RATES Injection rates are dependent on offset well producing rates. Site specific reservoir simulation models will also be used to determine best injection rates. Injection rates in excess of 10,000 barrels per day are anticipated. PRODUCTIVITY AND INJECTIVITY MONITORING OBJECTIVE Determine which vertical sections of the reservoir are being injected into and which are producing so adjustments can be made to maximize the vertical sweep efficiency of the waterflood. METHOD After initiation of pilot water injection conduct spinner surveys in each water injection well. Spinner surveys should also be conducted in offset producing wells if not previously run. After several months of water injection a second spinner survey will be considered for each injection well. Following this a survey should be considered if any significant change in injection characteristics occurs or following any well cleanout procedure. Spinner surveys with a fluid density indicator should be run in a producing well when it begins to produce water. Subsequent surveys should be considered when a producing well exhibits a significant change in producing characteristics or after any cleanout or zone isolation procedures. Experience with the monitoring program for the pilot injection and producing wells will be utilized to develop a monitoring program for the full field waterflood. This program can be submitted to the AOGCC prior to beginning the full field waterflood. it must be considered that wellbore configuration and operational limitations must be taken into account in the implementation of a recommended program. AOGCC SUBMISSIONS i. Water injection test results. II. Zone maps showing fluid corridors and well locations. III. Wellbore schematic showing either type well or specific well if applicable IV. Type log with zonal description. V. Schematic of waterflood facilities Vi. Waterflood plan - pilot objectives. VII. Monitoring program. INJECTION TEST RESULTS INJECTION TESTS COMPLETED ON SAG DELTA 10, P-14 AND 0-16 SAG DELTA 10 AND P-14 RESULTS Untreated seawater injected. Very low injectivity experienced Analysis indicated near wellbore plugging due to insufficient cleanup after perforating and/or corrosion products from untreated seawater injection. 0-16 RESULTS Injection test performed after approximately 1 month of production allowing for high rate cleanup. Oxygen scavenger utilized to reduce corrosion. Injectivities of 17 to 23 bbl/day/psi achieved at rates up to 4000 bwpd. Oxygen scavenging not entirely successful and near wellbore plugging again occurred. FUTURE PLANS No further testing planned until seawater treatment plant is in service. Flowback from 0-16 test will be analyzed. Appeared to be corrosion products. Plan for close oxygen control. Include convenient means of flowing back injection wells for cleanup if feasable.