ALBERTA S CARDIUM OIL AND THE EVOLUTION OF CUTOFFS AND EVALUATION PROCEDURES IN RESPONSE TO HORIZONTAL DRILLING

Transcription

1 ALBERTA S CARDIUM OIL AND THE EVOLUTION OF CUTOFFS AND EVALUATION PROCEDURES IN RESPONSE TO HORIZONTAL DRILLING Alberta s Cardium Oil and the Evolution of Cutoffs and Evaluation Procedures in Miranda Stoffman, P. Geol. Response to Horizontal Drilling 09/11/2015 GLJ PETROLEUM CONSULTANTS 1

2 INTRODUCTION The Goal To devise a methodology for evaluating the Cardium formation that is consistent, repeatable, and adaptable across the basin The Problem Horizontal drilling was expanding into the halo lands around vertical producers Insufficient OIIP volumes to match production from lower quality reservoirs Potential for bypassed drilling opportunities 2

3 INTRODUCTION The Solution To revise the evaluation methodology Identify new cut offs Include production potential from lower quality rock Low porosity, non-reservoir rock 3

4 OUTLINE Geology Overview Original Methodology Start of horizontal drilling Revised Methodology After production and drilling expanded Conclusion 4

5 CARDIUM AGE AND LOCATION Kakwa Carrot Creek Pembina Edmonton Willesden Green Garrington Lochend Calgary 5

6 CARDIUM TYPE LOG Pembina Field 100/ W5 CGL U SS/Sh M SS M Sh L SS L Sh Gamma 45 SS -15 Neutron Density ±10 SP Resistivity (Dashtgard et al. 2008) 6

7 GEOLOGY OVERVIEW Alberta s Cardium Fairway Paleogeographical Map: Late Turonian Age Cretaceous Western Interior Seaway 7

8 GEOLOGY OVERVIEW Shoreface Offshore Transition Offshore Upper Lower Lower shoreface / Upper offshore Inner Shelf / Lower Offshore Outer Shelf Med-fine grained Sands Dune + Ripple scale X-Strat Mean fairweather wave base Very fine to fine grained Sands with Interbedded Muds Hummocky X-Strat (HCS) Mean storm weather wave base Sands-Silts-Shales with Increased Bioturbation Mudstones (Wiseman, 2014) 8

9 GEOLOGY OVERVIEW Kakwa Carrot Creek Edmonton (Plint, Walker, Bergman, 1986) Pembina Willesden Green Garrington Lochend Calgary 9

10 GEOLOGY OVERVIEW Hundreds of cores Over 4200 wells Three hydrocarbon bearing zones: Conglomerate Sandstone Transition Transition from sands above to mudstone below Kakwa Carrot Creek Pembina Calgary Edmonton Willesden Green Garrington Lochend 10

11 CONGLOMERATE ZONE Top pay interval Clean but dense on logs Clast or Mud supported Siderite cements and nodules Phi from logs - difficult Ave Core phi = 6% Perm = 100 s s md Target for vert. production 4 cm 11

12 SANDSTONE ZONE Cleaning upward Interbedded sands + shales Very-fine to fine grained Hummocky X-Stratification Up to 30% Shale (at base) Phi = 4 % 18 % Rt >/= 20 ohms Perm = md Vintage Logs Target for vert. production 4 cm 4 cm 12

13 TRANSITION ZONE Bioturbated silts, sands, shales Shale content 30 % to 70 % Phi = 3.5 % 7 % Rt = ohms Perm = md Vintage Core Analysis non-reservoir rock Not perfed in vertical wells Horizontal drilling and new frac technology 4 cm 13

14 ORIGINAL METHODOLOGY Conventional approach used for cut-off s vertical vs. horizontal Hz production started in East Pembina limited data from extensive core and log analysis Wells subdivided CGL 6% phi, 10% Sw SS Cutoffs: 6% phi, Rt >/= 20 ohms Tr Cutoffs: 6% phi, 13 ohms < Rt > 20 ohms SS and Tr Sw from BVW values from SCAL 14

15 Water Saturation POROSITY VERSUS WATER SATURATION FROM SCAL 02/ W5 00/ W5 00/ W5 100 Cardium Sandstone BVW Plot Samples K<2.0 md Porosity Multi Well Data BVW for Sandstone / 270 BVW for Transition zone 15

16 ORIGINAL METHODOLOGY SAMPLE LOG EVALUATION 1 Conglomerate pay 0.5 m 6.0% Phi 10% Sw Sandstone pay 3.5 m 14.0% Phi 13% Sw Transition pay 0.0 m Does not meet the 6% Phi Cut-off 102/ W5 Total pay: 4.0 m 13.0 % Phi 13 % Sw Total HCPV = Gamma 45 SS -15 Neutron Density ±10 SP Resistivity 6% Phi C.O. 16

17 ORIGINAL METHODOLOGY SAMPLE LOG EVALUATION 2 Conglomerate pay 0.0m No CGL Sandstone pay 4.2 m 10.5% Phi 18% Sw Transition pay 0.0 m Does not meet the 6% Phi Cut-off 100/ W5 Total pay: 4.2m 10.5 % Phi 18 % Sw Total HCPV = Gamma 45 SS -15 Neutron Density ±10 SP Resistivity 6% Phi C.O. 17

18 ORIGINAL METHODOLOGY SAMPLE LOG EVALUATION 3 Conglomerate pay 0.0 m No CGL Sandstone pay 2.5 m 7.0% Phi 26% Sw Transition pay 0.0 m Does not meet the 6% Phi Cut-off 100/ W5 Total pay: 2.5m 7.0 % Phi 26 % Sw Total HCPV = Gamma 45 SS -15 Neutron Density ±10 SP Resistivity 6% Phi C.O. 18

19 Daily Oil (bbl/d) OIIP VERSUS PRODUCTION Hz W5 - Production Plot 100/ W5 Offset HCPV = Drainage Area = 160 Acres OIIP = 400 Mbbl At 10% Recovery Factor* Total recovery 40 Mbbl Should have been uneconomic but production says differently... Need more OIIP! 40 Cumulative Oil (Mbbl) *Recovery factors vary depending on completions, drilling programs, rock quality, etc. 19

20 WHAT S NEXT Insufficient OIIP volumes, when compared to horizontal production in lower quality reservoirs, could lead to missed opportunities for development... Methodology needs to evolve! 20

21 REVISED METHODOLOGY Need to quantify contribution from low grade rock Wells subdivided CGL 6% phi, 10% Sw same as original SS Cutoffs: - Shale Baseline Porosity Cut Off - Rt >/= 20 ohms - Sw from BVW values from SCAL Tr Cutoffs: - Shale Baseline Porosity Cut Off - 13 ohms < Rt > 20 ohms - Sw weighted BVW using Vshale Tr 21

22 REVISED METHODOLOGY SHALE BASELINE A A 100/ W5 102/ W5 100/ W5 100/ W Gamma 45 SS -15 Neutron Density Gamma 45 SS -15 Neutron Density Gamma 45 SS -15 Neutron Density Gamma 45 SS -15 Neutron Density 3% Shale baseline 4% Shale baseline 5% Shale baseline 6% Shale baseline A Pembina Field A 22

23 LOG NORMALIZATION W W W Gamma 60 SS 0 Neutron Density Gamma 45 SS -15 Neutron Density Gamma 45 SS -15 Neutron Density Regional Shale Baseline = 3% Log Shale Baseline = 1% Log Shale Baseline = 4% 23

24 REVISED METHODOLOGY SUBDIVISIONS AND CUT OFFS 100/ W5 Conglomerate No Change 6% Phi 10% Sw Gamma 45 SS -15 Neutron Density ±10 SP Resistivity 5% Shale baseline 24

25 REVISED METHODOLOGY SUBDIVISIONS AND CUT OFFS 100/ W5 Sandstone Phi C.O. = Sh B.L. Rt >/= 20 ohms Phi from normalized Density Cure Sw from BVW values from SCAL Gamma 45 SS -15 Neutron Density ±10 SP Resistivity 5% Shale baseline 20 ohms 25

26 Water Saturation SANDSTONE BVW PLOT FROM SCAL 02/ W5 00/ W5 00/ W Cardium Sandstone BVW Plot Samples K < 2.0 md y = x Porosity - Sw correlation for sandstone (BVW) Porosity tritium W5 invert mud, 103_ W5 Multi Well Data 26

27 REVISED METHODOLOGY SUBDIVISIONS AND CUT OFFS 100/ W5 Transition Phi C.O. = Sh B.L. 13 < Rt > 20 ohms Phi from normalized Density curve Sw from adjusted BVW accounts for transition zone shale content Gamma 45 SS -15 Neutron Density ±10 SP Resistivity 5% Shale baseline 13 ohms 27

28 TRANSITION VSH & VSS CALCULATIONS ΔPhi = Neutron Phi Density Phi 100/ W5 Vsh = ΔPhi Tr / ΔPhi Sh = 14 / 21 = 67% Vss = 100% Vsh = 33% Phi Tr ss = (Phi Tr (Vsh * Phi Sh)) Vss = (4% - (67%*3%) / 33% = 6% ΔPhi Tr ΔPhi Sh Gamma 45 SS -15 Neutron Density 28

29 TRANSITION SW CALCULATION BVW Tr = (Vsh * Phi sh * Sw sh) + (Vss * Phi Tr ss * Sw Tr ss) Vsh = ΔPhi Tr / ΔPhi Sh Phi sh = Shale Baseline Sw sh = 100% Vss = 1-Vsh Phi Tr ss = (Phi Tr (Vsh * Phi Sh)) / Vss Sw Tr ss = BVW ss / Phi Tr ss Sw Tr = BVW Tr / Phi Tr 29

30 REVISED METHODOLOGY SAMPLE LOG EVALUATION 1 Conglomerate pay 0.5 m 6.0% Phi 10% Sw Sandstone pay m % Phi 13 8 % Sw Transition pay m 3.5 % Phi 74 % Sw Total pay: m % Phi % Sw Total HCPV = Gamma 3% Shale baseline 102/ W5 45 SS -15 Neutron Density ±10 SP Resistivity Δphi Tr / Δ phi shale = 15/24 = 56% Transition Sand: 4.0% Phi, 43% Sw Shale: 3.0% Phi, 100% Sw Transition BVW =

31 REVISED METHODOLOGY SAMPLE LOG EVALUATION 2 Conglomerate pay 0.0m No CGL 100/ W5 Sandstone pay m % Phi 18 20% Sw Transition pay m Tight 4.0% Phi 64% Sw Total pay: m % Phi % Sw Total HCPV = Gamma 45 SS -15 Neutron Density 3% Shale baseline ±10 SP Resistivity Δphi Tr / Δ phi shale = 14/21 = 67% Transition Sand: 6.0% Phi, 28% Sw Shale: 3.0% Phi, 100% Sw Transition BVW =

32 REVISED METHODOLOGY SAMPLE LOG EVALUATION 3 Conglomerate pay 0.0 m No CGL 100/ W5 Sandstone pay m % Phi 26 31% Sw Transition pay 0.0 m Does not meet C.O. Total pay: m % Phi 26 31% Sw Total HCPV = Gamma 45 SS -15 Neutron Density 3% Shale baseline ±10 SP Resistivity 32

33 HCPV ORIGINAL VERSUS REVISED UWI Org Total Pay Org Ave Phi Org Ave Sw Org Total HCPV Rev Total Pay Rev Ave Phi Rev Ave Sw Rev Total HCPV 102/ W5 4.0m 13.0% 13% m 11.1% 21% / W5 4.2m 10.5% 18% m 6.5% 28% / W5 (for Hz - 102/04-03) 2.5m 7.0% 26% m 5.5% 31%

34 Daily Oil (bbl/d) CONCLUSION Hz W5 - Production Plot 100/ W5 Original HCPV = Over 160 Acres OIIP = 400 Mbbl At 10% Recovery Factor Total recovery 40 Mbbl Revised HCPV = Over 160 Acres OIIP = 700 Mbbl At 10% Recovery Factor Total recovery 70 Mbbl Cumulative Oil (Mbbl) Revised methodology has identified additional OIIP volumes Expected Recovery Actual Recovery! 34

35 CONCLUSION It s always important to compare the calculated Hydrocarbon Pore Volume, and subsequent OIIP, to the production data In clean sands with high porosity, and where shale Baseline is 6%, both methods calculate similar HCPV s When production and recovery factors are tracked over a period of time we can determine areas where cut offs need to be revised Look for missed potential development opportunities This is best done by maintaining an open dialogue between Geologists and Engineers Provides the most accurate reserves evaluation possible 35

36 THANKS GLJ Petroleum Consultants Main Contributors: Mirek Zaoral Dayna Muscoby Todd Ikeda 36

37 REFERENCES Dashtgard, S.E., Buschkuehle, M.B.E., Fairgrieve, B., Berhane, H Geological characterzation and potential for carbon dioxide (CO2) enhanced oil recovery in the Cardium Formation, central Pembina Field, Alberta. Bulletin of Canadian Petroleum Geology, v. 56, p Krause, F.F., Deutsch, K.B., Joiner, S.D., Barclay, J.E., Hall, R.L. and Hills, L.V Cretaceous Cardium Formation in the Western Canada Sedimentary Basin. In: Geological Atlas of the Western Canada Sedimentary Basin. G.D. Mossop and I. Shetson (cds.). Alberta Research Council and Canadian Society of Petroleum Geologists, p Pattison, S.A.J., and Walker, R.G. 1992, Deposition and interpretation of Long, Narrow Sandbodies underlain by a Basinwide Erosion Surface: Cardium Formation, Cretaceous Western Interior Seaway, Alberta, Canada. Journal of Sedimentary Petrology, v. 62, p Plint, A.G., Walker, R.G., and Bergman, K.M. 1986, Cardium Formation 6. Stratigraphic framework of the Cardium in subsurface. Bulletin of Canadian Petroleum Geology, v. 34, p Walker, R.G., and Eyles, C.H. 1991, Topography and Significance of a Basinwide Sequence-Bounding Erosion Surface in the Cretaceous Cardium Formation, Alberta, Canada. Journal of Sedimentary Petrology, v. 61, p Wiseman, A. 2014, Geologic Framework, Reservoir Characterization and Production Analyses of the Cardium Formation: Unconventionally Developed North West Pembina Field, Alberta, Canada. Thesis Submitted to the Faculty of Graduate Studies, Department of Geoscience, Calgary, Alberta, April