Evaluation of Oil Reservoir Characteristics To Assess North 课件.ppt

Quick Rules of Thumb Recovery factor using miscible CO2 is 8% -11% OOIP. Immiscible CO2 50% of miscible. MMP equals initial bubble point pressure. CO2 requirement is 7-8 Mcf/bo plus 3-5 Mcf/bo recycle. Water injection required to fill gas voidage and increase reservoir pressure to original BHP. WAG is alternative but 10 Mcf/bo still required. Top down CO2 injection alternative is effective but requires more capital investment for higher CO2 volume. Unfavorable Reservoir Characteristics for Empirical Screening High concentrations of vertical fractures. Very high, or very low, permeability. (Vertical segregation or fracture channeling) Thick reservoirs with no layered horizontal permeability barriers. Reservoirs with poor connectivity. Well spacing 80 acres. Poor material balance during water flood. (High water loss out of zone, water influx or high water cut during primary production) U.S. Active CO2 Floods Texas 48 (26 Succ, 8 TETT, 13 Prom, 1 Fail) Wyoming 5 (5 Success) Oklahoma 4 (2 Success, 1 TETT, 1 Promising.) Utah 2 (1 Success, 1 Promising) Mississippi 2 (1 Success, 1 Promising) Michigan 2 (1 Success, 1 TETT) New Mexico 2 (1 Success, 1 Promising) Colorado 1 (1 Success)__________________ Total 66 (38 Success, 10 TETT, 17 Prom.) * First CO2 Flood SACROC Jan 1972 Summary of US CO2 Active Floods (CEED 2002) Total Active CO2 Floods = 66 Total Successful = 38 Total Successful Carbonates = 29 Total Successful Sandstones = 9 Of 29 Successful Carbonate Units, 18 are in San Andres Dolomite. Reservoir Characteristics of 29 Successful Carbonate CO2 Floods 2002 US Average North Dakota Madison Porosity 11% (7%-13.5%) 10.9% Permeability 9 Md (1.5-62) 10.2 Md Depth 5,281 feet (4500-8000) 7,500 feet API 33 degrees (28-41) 38.7 degrees BHT 108 degrees F (86-1