Update of Lost Soldier/Wertz Floods Living in a Constrained CO 2 Environment

Transcription

1 Update of Lost Soldier/Wertz Floods Living in a Constrained CO 2 Environment Karan E. Eves Juan J. Nevarez Presented at the 15 th Annual CO 2 Flooding Conference December 10-11, 2009 Midland, Texas

2 Agenda Field Background Location Geological Information Field Development Field Process Overview Field Performance Reservoir Properties Historical Production CO 2 Constraints CO 2 Historical Purchases CO 2 Allocation Process New WAG Management Tools Case Studies Wertz Tensleep Lost Soldier Cambrian Future Challenges

3 Location

4 Geological Information Tensleep Contour Map Lost Soldier Field Wertz Field

5 Geological Information Lost Soldier and Wertz are both faulted anticlines. Located in Wyoming s Great Divide Basin

6 Field Statistics Field Size : 5,500 Acres Productive Acres: 4300 Reservoir Depth: ft Pay Thickness: +/ ft OOIP: 660 MMBO Cum Recovery: 342 MMBO

7 Field Development Lost Soldier Tensleep Discovered Lost Soldier Darwin-Madison Discovered Lost Soldier Cambrian Discovered 1962 Lost Soldier Field Unitized 1999 Merit Energy Company Purchased Field 1930 s 1940 s 1950 s 1960 s 1970 s 1980 s 1990 s 2000 s 1980 s CO2 Floods Initiated 1979 Wertz Cambrian Discovered 1970 s Water Floods Initiated 1948 Wertz Darwin-Madison Discovered 1937 Wertz Field Unitized 1937 Wertz Tensleep Discovered

8 Field Process Overview Field Statistics Oil Production : NGL/CND : Water Production: Gas Recycle Vol: Makeup CO2: 6200 bpd 1250 bpd 210,000 bpd 150,000 mcfd 14,000 mcfd CO2 Recycle Plant Satellite Main Battery Oil Pipeline Production Wells 235 Water Injection Plant Injection Wells 162

9 Reservoir Background Critical Reservoir Properties for the three main producing formations: Field Lost Soldier Wertz Air Perm md Res Press psi Formation Lithology Average Depth Formation Thickness Average Porosity Current Spacing Tensleep SS 5, % ,800 Darwin SS 5, % ,650 Madison LS/DOL 5, % ,650 Cambrian SS 7, % ,700 Tensleep SS 6, % ,500 Darwin SS 6, % ,300 Madison LS/DOL 6, % ,300 Primary production was attributed to fluid expansion, water influx and gravity drainage All of the formations above are currently CO 2 flooded Miscibility Pressure 2,350 psi

10 WZTP Flood LSTP Flood LSDM Flood LSCA Flood WZDM Flood bopd CO 2 Injection Begins Merit Assumes Operation Historical Production 100,000 Bairoil Complex - Lost Soldier & Wertz Fields 10,000 Historic Oil Production Forecast Oil Production Under Amoco Actual Oil Production Under Merit 1,

11 CO2 Daily Purchases MMCF/Day Cumulative Purchases BCF Historical CO 2 Purchases Lost Soldier and Wertz CO2 Purchases Daily Purchases Cumulative Purchased Jan-86 Jan-89 Jan-92 Jan-95 Jan-98 Jan-01 Jan-04 Jan-07 0

12 Cumulative Incremental Oil, %OOIP Reservoir Maturity & Recovery Cumulative Incremental Oil vs Cumulative CO2 Injection LSCA LSDM LSTP WZDM WZTP Cumulative CO2 Injection, % HCPV

13 Utility Factor (mcf of CO 2 per Incremental bbl of Oil) Utility Factor Bairoil Floods --- CO 2 Utility (Economic Basis) 70 LSCA LSDM 60 LSTP WZDM WZTP % 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% HCPVSI This plot considers incremental oil production calculated using the more generic economic method. A baseline decine is determined before tertiary recovery, & incremental oil then represents all production above this baseline.

14 CO 2 Allocation Process Step 1: Step 2: Step 3: Step 4: Step 5: Review Historical Production/Injection by Reservoir Developed Ideal CO 2 Injection at a Pattern Level Combined Ideal CO 2 Injection at a Reservoir and Complex level to determine variance with actual constrained volume Revise Ideal CO 2 Injection based on constrained CO 2 Volumes at a reservoir and pattern level Finalized WAG schedule & developed WAG management tool

15 WAG Management Tools Water CO 2 Set Set Points Flags Zero Rates Overdue Switches Days to Completion Cycle Volumes

16 Before & After WAG

17 Monthly Averages Wertz Tensleep 1,000,000 WZTP Production History (Process Rate - Corrected) 100,000 10,000 1, Oil Production, bopd Water Production, bwpd 10 Gas Production, mcfpd Water Injection, bwpd 1 CO2 Injection, mcfpd Process Rate Corrected Oil Production, bopd

18 Production Impact

19 Monthly Averages Lost Soldier Cambrian 100,000 LSCA Production History 10,000 1, Oil Production, bopd Water Production, bwpd 10 Gas Production, mcfpd Water Injection, bwpd 1 CO2 Injection, mcfpd Process Rate Corrected Oil Production, bopd Original Waterflood Performance Prediction

20 Phased Map of Cambrian DownSpacing Phase I LSCA 10 Convert to injection LSTP 89 - Deepen well & convert to injection LSDM 156 Deepen well & convert to injection Phase II LSCA 53 Horizontal Sidetrack & convert to injection. LSCA 234 New Horizontal Producer LSCA 233H New Vertical Producer Phase III LSCA 120 Convert to producer LSCA 49 Convert to injector LSCA 108 Horizontal Sidetrack Injector LSCA 235 New Horizontal Producer

21 Future Challenges Identifying best methods to improve reservoir conformance Working with Dow & reviewing polymer/gel treatments CO 2 Recycling Capacity Installing additional compression capacity Water Disposal Capacity Identifying reservoirs for waterflood, disposal candidates Maximizing CO 2 Utilization