1. Cook Inlet Natural Gas Reserves
Study
Islin Munisteri, EIT
John Burdick, Jack Hartz PE
State of Alaska, Department of Natural Resources Division of Oil and Gas
December 10, 2015
Society of Petroleum Engineers / Alaska Geological Society /
Geophysical Society of Alaska Joint Meeting

2. Overview
• Geological Setting of Cook Inlet
• Historical Trends
• Assumptions
– Decline analysis
– Material balance
• Discussion
2

3. Stratigraphic Column
3

4. Cook Inlet Basin
• Coal-sourced biogenic gas in
Sterling, Beluga, and Tyonek
• Thermogenic oil from Jurassic
source in Hemlock and lower
Tyonek Formations
• Most large structures have
been drilled
• Smaller structural traps and
perhaps numerous
stratigraphic traps remain to be
discovered
• Inaccessible lands
• Map shows base of Tertiary
structure
4
Shellenbaum and
others, 2010
(DNR)
A’
A

5. 5
Middle Jurassic Tuxedni
source rocks at oil
window maturity
A’A
Bacterial gas from coals
Cook Inlet Petroleum Systems

6. 6

7. 7
Lewis River Unit
Stump Lake Unit
Ivan River Unit
Otter Unit
Pretty Creek Unit/ Gas Storage
Beluga River Unit
North Cook Inlet Unit
Lone Creek Unit
Three Mile Creek
Moquawkie Unit
Nicolai Creek Unit
Kitchen Lights Unit
Granite Point Unit
McArthur River
West McArthur
River Unit
Redoubt Unit
Middle
Ground
Shoal
Birch Hill Unit
Swanson River Unit /
Kenai Gas Storage 1,3
Beaver Creek
Unit
Wolf Lake

8. 8
West Fork Field
Sterling Unit
Cannery Loop/
CINGSA
Kenai Unit /
Pool 6 Storage
Kasilof Unit
Ninilchik Unit
Deep Creek Unit
Nikolaevsk Unit
North Fork
Unit

9. Gas Field Startups:
Includes Production Tests
9

10. Average age of fields = 30 years
10

11. Petroleum Resources Management
System
11PRMS resources classifications, as adapted from SPE et al., 2011.

12. Petroleum Resources Management
System
12PRMS resources classifications, as adapted from SPE et al., 2011.

13. Breakdown of Reserves for Cook Inlet
Study
• Proved Reserves (1P) =
Well-Level Decline Curve Analysis for Gas
+
Pool-Level Decline Curve Analysis for
Associated Gas
13

14. Petroleum Resources Management
System
14PRMS resources classifications, as adapted from SPE et al., 2011.

15. Breakdown of Reserves for Cook Inlet
Study
• Probable Reserves =
Upside Well Level Decline Curve Analysis for
Gas
+
Material Balance
15

16. Petroleum Resources Management
System
16PRMS resources classifications, as adapted from SPE et al., 2011.

17. Breakdown of Reserves
for Cook Inlet Study
• Proved Reserves (1P) =
Well-Level Declines for Gas +
Pool-Level Decline for Associated Gas
• Probable Reserves =
Upside Well Level Declines for Gas +
Material Balance
17
+
= 2P (Proved + Probable) Reserves

18. Decline Analysis: North Cook Inlet
18

19. Material Balance: North Cook Inlet
19

20. 20

21. Decline Curve Analysis (Exponential)
• Decline = [ ln (Qi / Q) ] / t
• Remaining Reserves as of 9/30/2015 onwards =
[ ( Qi – Qf ) / Decline ] *f
• T = time, months
• Decline = nominal decline, gas rate / month
• Qi = initial gas rate, mcfd
• Qf = final gas rate = 50 mcfd
21

22. 22
Decline = [ ln (Qi / Q) ] / t
= [ln (2000 mcfd/900 mcfd) / 4.3 years
= 0.185/year
RR = [ ( Qi – Qf ) / Decline ] *f
= [900 mcfd – 50 mcfd)/0.185] *365
= 1,677,027 mcf
= 1.6 bcf
CUM = 5.3 bcf
EUR = CUM + RR
= 5.3 + 1.6
= 6.9 bcf

23. 23

24. Solution
24

25. 25
2P Reserves
Probable
Reserves
8308
681
30
711
101
371
472
1183
7600
7800
8000
8200
8400
8600
8800
9000
9200
9400
9600
Cumulative
Produced
Base Case
Decline Analysis
(Gas Pools)
Associated Gas
(Oil Pools)
Total Proved
(1P) (Maintain
Existing Wells)
Upside Case
Decline Analysis
(Mitigate Well
Problems)
Material Balance
(Add
Compression
etc.)
Total Probable
(Additional
Investment)
Total Proved +
Probable
Remaining (2P)
GasProducedandRemaining,BCF
Remaining Reserves in the Cook Inlet Basin
1P 2P
1P
Proved
Reserves

26. 26

27. 27

28. 28
0
50
100
150
200
250
300
350
NorthCookInlet
BelugaRiver
Kenai
Ninilchik
McArthurRiver
TradingBay
NorthFork
KenaiC.L.U.
KenaiLoop
BeaverCreek
MiddleGroundShoal
SwansonRiver
GranitePoint
LewisRiver
LoneCreek
IvanRiver
PrettyCreek
StumpLake
DeepCreek
Moquawkie
NicolaiCreek
Sterling
Kasilof
RedoubtShoal
WestFork
WestForeland
WolfLake
ThreeMileCreek
Nikolaevsk
WestMcArthurRiver
Kustatan
AlbertKaloa
Hansen
BirchHill
RemainingReserves,BCF
Remaining Reserves - All Cook Inlet Fields
Base Case Decline Analysis Upside Case Decline Analysis Material Balance Associated Gas

29. 29
0
10
20
30
40
50
60
70
80
McArthurRiver
TradingBay
NorthFork
KenaiC.L.U.
KenaiLoop
BeaverCreek
MiddleGroundShoal
SwansonRiver
GranitePoint
LewisRiver
LoneCreek
IvanRiver
PrettyCreek
StumpLake
DeepCreek
Moquawkie
NicolaiCreek
Sterling
Kasilof
RedoubtShoal
WestFork
WestForeland
WolfLake
ThreeMileCreek
Nikolaevsk
WestMcArthurRiver
Kustatan
AlbertKaloa
Hansen
BirchHill
RemainingReserves,BCF
Remaining Reserves - Cook Inlet Fields < 100 BCF Reserves
Base Case Decline Analysis Upside Case Decline Analysis Material Balance Associated Gas

30. 30
2P Reserves
Probable
Reserves
8308
681
30
711
101
371
472
1183
7600
7800
8000
8200
8400
8600
8800
9000
9200
9400
9600
Cumulative
Produced
Base Case
Decline Analysis
(Gas Pools)
Associated Gas
(Oil Pools)
Total Proved
(1P) (Maintain
Existing Wells)
Upside Case
Decline Analysis
(Mitigate Well
Problems)
Material Balance
(Add
Compression
etc.)
Total Probable
(Additional
Investment)
Total Proved +
Probable
Remaining (2P)
GasProducedandRemaining,BCF
Remaining Reserves in the Cook Inlet Basin
1P 2P
1P
Proved
Reserves

31. Thank you!
• John Burdick
• Jack Hartz (retired)
• Paul Decker
• Laura Gregersen
• Becca Hulme
• Family
31

32. P/z
32

33. Pipelines
33

34. 34

35. 35

36. 36

37. 37

38. 38