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DESIGN AND IMPLEMENTATION OF A CO2 FLOOD UTILIZING ADVANCED RESERVOIR CHARACTERIZATION AND HORIZONTAL INJECTION WELLS IN A SHALLOW SHELF CARBONATE APPROACHING WATERFLOOD DEPLETION. Based On DOE Report # DOE/BC/14991R36 Presented by M. K. Moshell, P.E. 12/12/02.
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DESIGN AND IMPLEMENTATION OF A CO2 FLOOD UTILIZING ADVANCED RESERVOIR CHARACTERIZATION AND HORIZONTAL INJECTION WELLS IN A SHALLOW SHELF CARBONATE APPROACHING WATERFLOOD DEPLETION • Based On DOE Report # DOE/BC/14991R36 • Presented by M. K. Moshell, P.E. 12/12/02
Cooperative Agreement Number: DE-FC22-94BC14991 Participant Organization: Phillips Petroleum Company 4001 Penbrook Odessa, Texas 79762 (Now ConocoPhillips) Date of Report: 09/01/2002 Award Date: 06/03/1994 Completion Date: 07/01/2001
Special “Thanks” to Michelle Navarette
Project Purpose: To economically design an optimum carbon dioxide (CO2) flood for a mature waterflood nearing its economic abandonment. The original project utilized advanced reservoir characterization and CO2 horizontal injection wells as the primary methods to redevelop the South Cowden Unit (SCU), Ector County, Texas.
The Unit was a mature waterflood with water cut exceeding 95%. Oil must be mobilized through the use of a miscible or near-miscible fluid to recover significant additional reserves. Also, because the unit is relatively small, it does not have the benefit of economies of scale inherent in normal larger scale projects. Thus, new and innovative methods are required to reduce investment and operating costs.
Two primary methods planned to accomplish improved economics were use of : • Reservoir characterization to design and restrict the flood to the higher quality rock in the unit, and • Use of horizontal injection wells to cut investment and operating costs
Property Details Low permeability San Andres reservoir, 4,600’ At Eastern edge of San Andres productive trend on Central Basin Platform ~ 2200 Acres in Unit, ~500 Acres CO2 Flood area 20 Acres /wellbore on edges 10 Acres/wellbore in thicker pay area of Unit Slow waterflood processing rate Economic limit and abandonment was predicted for 1999
Early Results • The first two lateral CO2 injectors were drilled in the thickest portion of the reservoir • Oil production response to that injection was less than predicted • Laterals were drilled from existing producers • Additional injectors were drilled as vertical wells
9 8 3-01 116W 107 3-05W 105 103 127 135 7 146W 3-02 101A 140 122 106 128 114 3-07 131 112 217 2-05 104 12 143 3-03 102A EMMONS UNIT 136 210 2-10 3-06 218 108 111 123 2-04 203W 142 211 2-15W 201 132 3-04 16 2-01 109 2-18 2-22 208 209 205 110 2-20 2-19W 2-27W 215W 2-03 2-09 2-25 17 204 213 2-08 2-17 2-12 6-16W 202 2-24 2-21 6-27W 1-01 6-05 2-23 2-02 6-26W 1-03 2-11 6-06 4-03W 1-06 6-28W 2-26W 2-07 6-02 18 6-19 1-04 6-14 7-08 2-13W 6-01 4-02 5-07 7-01 7-15 6-20 1-02 5-02 6-23 5-01W 7-13 8-10 7-10 1-05 7-02 6-09A 8-18 7-06 5-08 7-05 1-07 13 5-03 6-07 6-03W 7-C11H 6-C25H 6-17 8-12 6-24 7-03W 8-17 9-01 5-05 6-21 8-06 6-13 7-04W 5-04W 7-09 9-03 7-12 6-08 6-22 8-14 8-19 8-04W 8-08W 6-04 8-13 8-02 8-02 5-06W 9-02W 6-18 6-10 8-03 8-16 8-15W 6-12W 8-05 6-11W 8-09W S. COWDEN UNIT PHASE I - SHORT RADIUS DRILLING Original Trajectories Actual Trajectories LEGEND Active Water Injection Well Proposed Locations Scale 1:8000. Proposed WIW to Convert to POW TA'd or SI Prod. Well P & A Prod. Well feet 1000. 0. 1000. 2000. 3000. 4000. 5000. Wells To Be Shut In Prop. CO2 Inj.(WAG)/Currently Active WI TA'd WIW rowen 1/00 Active Prod. Oil Well msb PRO97CGD.GPF P & A WIW D&A or P&A - Oil
Challenges – Phase 2 • Inject CO2 at higher rates to improve flood economics • Keep CO2 injection within the target reservoir layers • Increase total production rate without fracturing out of zone
Oil Recovery Summary MMSTBO % OOIP PROJECT AREA Estimated Original Oil in Place, Project Area 86.5 Most Likely Estimated Ultimate Tertiary recovery 3.7 4.3 UNIT Estimated Original Oil in Place, Unit* 117 100 Estimated ultimate oil recovery, Primary + Secondary** 35.8 30.6 Cumulative recovery to 6/30/02 36.3 31.0 Cumulative Tertiary recovery to 6/30/02 0.6 0.5 Est. Ultimate Primary + Secondary + Tertiary 39.5 33.8 Most Likely Estimated Ultimate Tertiary recovery 3.7 3.2 High Side Estimated Ultimate Tertiary recovery 4.5 3.8
12/11/02 Update Current Production 680 BOPD 2,800 MCFD 5,500 BWPD Oil production has been rising steadily since April 2002 (April 2002 = 600 BOPD)
Conclusions • Reservoir characterization partially successful • Simulation provided a forecast which was too optimistic on total liquid production and BOPD • Ultimate Tertiary Oil recovery ~ 40% of predicted • Liquid production rate still too low
Conclusions • Oil response good where CO2 Injection rate is maintained at target injection rates • Overall oil response is poor due to inability to maintain CO2 injection rate in-zone in most injectors • Water injection for gas mobility control in the future will slow flood even more