Assessing Technical and Economic Recovery of Oil Resources

More documents

Recommendations

Info

have favorable TZ/ROZ characteristics. Three of the study fields –Wasson’s Denver and Bennett Ranch Units and Seminole’s San AndresUnit – currently have CO2-EOR based ROZ pilot projects within their fieldboundaries. The Vacuum Field was selected for its highly tilted oil-watercontact inferring a large potential ROZ. The Robertson Field was selectedfor its disproportionately large residual oil zone compared to its main payzone (MPZ).6. In-depth reservoir simulation shows that, when properly designed,the oil resource in the TZ/ROZ can be efficiently recovered withoutexcess production of water. Based on detailed reservoir simulationresults, as set forth in this report, the low to residual saturation oil in theTZ/ROZ is technically recoverable using CO 2 -EOR. In examining thefeasibility of producing the TZ/ROZ resource, the study identified two keys:1) deepen and complete wells in the full transition zone and in the upperportion of the residual oil zone; and 2) where possible, conduct theTZ/ROZ CO 2 flood jointly with the main pay zone (MPZ) CO 2 flood.The generally thin transition zone contains oil that ranges from moderate,mobile oil saturations to low, immobile oil saturations and should alwaysbe included in the completion interval. The generally thicker residual oilzone has oil saturations that decline from immobile at the top of the ROZ(±35%) to near zero at the base of the oil column, Figure EX-1. Thesaturation profile and how it tails off (abruptly or gently) is important indetermining the optimum TZ/ROZ completion interval and the associatedROZ oil resource target. (Further complicating the ROZ completioninterval selection is the potential for water coning in the producing wellsdue to aquifer influx. As further discussed in the report, this may bemitigated by completing wells higher in the ROZ interval.)EX-3 February 2006
4800Oil Saturation %100 048504900495050005050OWC51005150Main Pay Zone (MPZ)Base of Producing OWCTransition Zone (TZ)520052505300Residual Oil Zone (ROZ)535054005450Base of Ultimate OWCFigure EX-1. Oil Saturation Profile in the TZ/ROZ:Adapted from Wasson Denver Unit Well.7. Simultaneous application of CO 2 -EOR to the main pay zone and theTZ/ROZ provides superior results compared to flooding these tworeservoir zones individually. Our in depth reservoir simulation showsthat simultaneous main pay zone (MPZ) and transition zone/residual oilzone (TZ/ROZ) CO 2 floods are superior to individual MPZ and TZ/ROZfloods, using the Wasson Denver Unit reservoir and fluid properties as theoil field example. When these two reservoir units are CO 2 floodedsimultaneously, the project recovers nearly 20% more oil than when thesetwo reservoir units are CO 2 flooded separately. This is due to much moreefficient use of CO 2 , improved pressure balance in the oil column andmore efficient capture of the displaced oil. The most significant of these isthe reduction in the out of zone movement of the injected and displacedfluids (CO 2 , oil and water).EX-4 February 2006
Page 1 and 2: ASSESSING TECHNICAL AND ECONOMICREC
Page 3: ASSESSING TECHNICAL AND ECONOMIC RE
Page 6 and 7: EXECUTIVE SUMMARYOur first study,
Page 10 and 11: 8. The technically recoverable ROZ/
Page 12 and 13: When conducted simultaneously, each
Page 14 and 15: saturation left after waterflooding
Page 16 and 17: 4800Oil Saturation %100 04850490049
Page 18 and 19: WEOil TrapROZROZProducingOWCBase of
Page 20 and 21: WEOil TrapROZROZProducingOWCBase of
Page 22 and 23: 5,400 5,300 5,200 5,100 5,0006,000
Page 24 and 25: 6,000 5,900 5,800 5,700 5,600 5,500
Page 26 and 27: C. Evidence for ROZs in the Permian
Page 28 and 29: III. EVALUATING OIL RECOVERY FROM R
Page 30 and 31: Estimates of MPZ and ROZ oil produc
Page 32 and 33: Producing OWCAdapted from Oxy Permi
Page 34 and 35: The initial forecasts of oil respon
Page 36 and 37: B. Sample ROZ Oil Fields. Five majo
Page 38 and 39: Basin Name Permian West Texas 8A15
Page 40 and 41: Seminole San Andres Unit Production
Page 42 and 43: Basin Name Permian West Texas 8A19
Page 44 and 45: Basin Name Permian East New Mexico4
Page 46 and 47: IV. CALIBRATING THE OIL RECOVERY MO
Page 48 and 49: PROPHET input file to account for t
Page 50 and 51: 1,400Reservoir Simulation1,200Proph
Page 52 and 53: Table 3. Technical Oil Recovery Tot
Page 54 and 55: the full TZ in the TZ/ROZ CO 2 -EOR
Page 56 and 57: • Methodology. Reservoir simulati
Page 58 and 59:
Development of the reservoir starte
Page 60 and 61:
VI. ECONOMICALLY RECOVERABLE OILRES
Page 62 and 63:
• Finally, the largest single cos
Page 64 and 65:
These 1.4 billion barrels of oil re
Page 66 and 67:
APPENDIX AOIL IN-PLACE FOR THE TZ A
Page 68 and 69:
Table A-1. Key Inputs for Calculati
Page 70 and 71:
ADJUSTING THE ROZ OIL IN-PLACE VALU
Page 72 and 73:
APPENDIX CECONOMIC ANALYSES OF FIVE
Page 74 and 75:
Field Cashflow Model Pattern FieldS
Page 76 and 77:
Field Cashflow ModelStateFieldForma
Page 78 and 79:
BasinFieldFormationTechnology CaseD
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
show all

Assessing Technical and Economic Recovery of Oil Resources

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?