Department of Commerce, Community, and Economic Development
Alaska Oil and Gas Conservation Commission
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HomeMy WebLinkAbout2015 Northstar Oil PoolH
Hilcorp Alaska, LLC
March 301h, 2016
Post Office Box 244027
Anchorage, AK 99524-4027
3800 Centerpoint Drive
Suite 100
Anchorage, AK 99503
Phone: 907/777-8414
Fax: 907/777-8580
ddurry@hilmrp.com
Cathy Foerster, Chairman
Alaska Oil & Gas Conservation Commission
333 W. 7th Avenue, Suite 100 4 E. G, �t M K E 0
Anchorage, Alaska 99501-3539 �,�AR 3 3 201h
RE: NORTHSTAR UNIT, NORTHSTAR FIELD, NORTHSTAR OIL POOL, STATE OF ALASKA,
2015 ANNUAL RESERVOIR REVIEW
Dear Commissioner Foerster:
In accordance with Conservation Order No. 458A, Hilcorp Alaska, LLC ("Hilcorp"), as Operator, hereby submits for
your review the following Annual Reservoir Review for the Northstar Field.
This is the 15th Annual Reservoir Review and corresponds to events during the 2015 calendar year. Note that the
Northstar Field has been on production since November 2001.
A. Progress of Enhanced Recovery Project and Reservoir Management Summary
During 2015, no new wells were drilled or sidetracked in the Northstar Unit. Therefore the locations of all the
wells in the Northstar Unit have remained unchanged.
Production and injection statistics are summarized in Table 1. Average daily oil production from the Northstar
field was 8,125 bopd and average daily gas injection was 493.9 mmscfpd. The reservoir voidage balance values
reported do not include oil production from satellite well NS34A or Kuparuk zone production from well NS08.
During 2015, gas injection was calculated to be 19,233 thousand -reservoir barrels (MRB) more than reservoir
voidage. At year end, the reservoir overall cumulative voidage replacement ratio was 1.027. The average of
reservoir pressure control for 2015 was 5,128 psia.
Hilcorp became the official Operator of the Northstar Field effective November 18, 2014. As a result, the historic
reservoir simulation model developed by the previous operator will no longer will be utilized. Hilcorp will continue
working towards an Ivishak reservoir simulation model for enhanced recovery optimization during 2016.
ECOPY
Table 1: NORTHSTAR FIELD 2015 OVERVIEW STATISTICAL SUMMARY
WELL STATISTICS
Produced Fluids
As of 1 2131/2 01 5 Full year (1)
As of Dec -14 (2)
Producers 17
16
Injectors 8
8
NOTES:
(1) Well count data reflects ONLY those w ells which contributed to productionlnjection
during the respective year
(2) Active wells as of December 2015
Pilot/Purge
PRODUCTION/INJECTION STATISTICS
Cumulative Start.
Up through
Production
2015
12131/15
Oil (BBL)
2,965,447
165,280,737
Gas (MCF)
180,279,163
2,030,194,931
Water (BBL)
3,790,058
57,744,147
Injection
Water (BBL) into NS10 & NS32 Disposal Well
3,790,058
62,148,862
Gas (MCF)
194,141,213
2,238,529,426
Balance (excludes satellite nell NS -34A and NS08 Kup oil Production)
Cum,
stadup,
Cum Production (MRS)
362,439
1,479,251
Cum Injection (MRS)
381,672
1,519,186
Over/Under (MRB)
19,233
39,934
DAILY AVERAGE RATE DATA 2015
MRS
Gas, MRS
Production
MRS
MRS
Oil, BOPD
8,125
MRS
Gas, MCF/D
493,916
10,944
Water, BWPD
10,384
11,541
Injection
11,340
887
Water, BWPD
10,384
1,399,486
Gas, MCFPD
531,894
33,610
AVERAGE RESERVOIR PRESSURE
529
9,891
Average of surveys obtained in 2015
5,128
psia
B. Voidaee Balance by Month of Produced Fluid and Iniected Fluids - 2015
Page 2
Produced Fluids
Injected Fluids
Net nle ion
llnlection- Production)
Pilot/Purge
Cum
Total
Formation
/Flare 8
Total
Year
Cum since
Net
Year
since
Water,
Voidage,
Year
Cum since
Gas,
Import
injection,
Cum,
stadup,
Injection,
Cum,
start-up,
Month
Oil, MRS
free Gas, MRS
MRS
MRS
Cum, MRS
startup, MRS
MRS
Gas, MRS
MRS
MRS
MRS
MRS
MRS
MRS
Jan -2015
597
10,944
378
11,541
11,541
1,365,876
11,340
887
12,227
12,227
1,399,486
686
686
33,610
Feb -2015
529
9,891
366
10,420
21,962
1,378,296
10,242
741
10,983
23,210
1,410,469
563
1,248
34,173
Mar -2015
670
11,277
395
11,947
33,908
1,388,242
11,721
801
12,522
35,732
1,422,991
576
1,824
34.748
Apr -2015
631
10,462
376
11,093
45,002
11399,336
10,881
815
11,696
47,428
1,434,687
603
2,426
35,351
May -2015
532
8,811
330
9,343
54,345
1.408,679
9,164
601
9,765
57,192
1,444,451
421
2848
35,772
Jun -2015
429
7,262
266
7,691
62,035
1,416,370
7,546
602
8,348
64540
1,452,799
657
3,505
36,430
JN -2015
535
9,699
342
10,234
72,269
1,426,603
10,053
815
10,869
76,409
1,483,668
635
4,140
37,065
Aug -2015
471
9,093
311
9,564
81,833
1,436,167
9,405
785
10,190
86,599
1,473,856
626
4,766
37.691
Sep -2015
516
9,741
344
10,259
92,092
1,446,426
11l064
782
10,876
97,475
1,484.734
617
5,383
3AWS
Oct -2015
556
10,205
319
10,761
102,853
1,457,187
10,574
782
11,355
106,831
1,496,089
595
5,978
38,903
N.2015
584
10,332
272
10,916
113,769
/,40,103
10,720
763
11,483
120,313
1,507,572
566
6,544
39,469
Dec -2015
588
10,470
292
11,058
124,827
1,479,161
10,860
759
11,619
131,932
1.519,191
561
7,105
40,0.30
2015 Totals
6,839
118,188
3,991
124,827
122,590
9,342
131,932
7,105
Page 2
C. Summary and Analysis of reservoir Pressure surveys within the pool
Static bottom hole pressures collected in 2015 are summarized below.
These pressures have been included with the historical Ivishak reservoir pressure data and are graphically
represented in the next figure.
Page 3
STATE OF ALASKA
ALASKA OIL AND GAS CONSERVATION COMMISSION
RESERVOIR
PRESSURE REPORT
1. Gperdw:
3.-,,a,
Cocap AYska, LLC
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3. UNortxase Krre:
4.F.B.N Mkhortl'star FeW
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10.Ty5e
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13. Rrlaaleo
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18 R"M
19. Fna1
21 WWm
21. Ressure
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See
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Natnellon¢
9ditnew 6
Isea
Pressures
imtrudore
7001 cepN
_
.1 orCM -
NS24
MMU31110000
O
590100
Mshak
10,987.10,992
4/19/15 2 SBHP 252
11,040•
5,125
11,100
11.007.11,047
0.46
5,153
NS1s
50029231020000
O
590100
Iashak
10,970-11,048
WW15 2 SBHP 252
11,027
5,118
11,100
0.46
5,152
N54B
50029230880000
0
590100
Mahal,
11,036•-11,155'
8/22/15 40 PBU 246
10,581
5,035
11,100
0.11
5,092
Ns -0
50029232440000
O
5WIW
IMshak
10,9111
W23/15 64 PBU 247
10,684
5,038
11,100
011
5.084
NSAM
500292309601W
O
590100
IJshak
11.085'-11.146'
8/2315 64 PBU 2330.11
10,
5,043
11,1 00
5,1 53
NS -2B
5(x29232480000
0
5(xiW
Mshak
11108'-11,150'
9/19/15 114 SBHP 244
11,0]6374
5,126
11,100
0.10
5,728
NS -13
500292W1]00(x
O
5(x100
Ivshak
1 1,058'-11,090'
11&15 74 SBHP 245
10,739
5.089
11,100
0.10
5,124
NS45
SMWW730000
O
580100
Nshak
11.037-11.007'
11/12/15 57 SBHP 254
10,954
5,114
11,1(x
OW
5,12]
NS -14A
5(x29230260100
0
5901W
Iashek
11,009'-11,097
11/18115 244 SBHP 254
11p43
5,127
11,100
0.10
5,133
NS -0
50029230520000
O
SW100
14shak
11,063'41,085'
11/19/15 249 SBHP 247
10,744
5,057
11AW
0.10
5,092
Ns4
50029230080(x0
0
500150
KWmk
8,924'-8,981'
1218/15 q8 PBU 192
8,7]8
3,771
9,(x0
0.11
3,841
Comments:
23 Attests rear@E
hereN were Moon in accordance
wMtheapglcabk
rules, reg hs am ire"otart of Me Alaska 01eM (Ya Cun¢ervMbn Cgrrncabn
I4MN cer ffy Nal the
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S'ratme
Title
f1eservpY 5lpner
R'n1N Naim
prs Itanyar
DaM
bhuary 6. 2116
These pressures have been included with the historical Ivishak reservoir pressure data and are graphically
represented in the next figure.
Page 3
NSO6 • NS07 -. NS08 x NS09 • NS12 , NS13 S14
NS15 • N816 NS17 • NS18 NS19 NS20 NS21
• NS22 NS23 NS24 4 NS25- NS27 • NS29 NS31
NS05 . NS28 NS11 • NS30 • NS33A + Avemge Pmmm
5250
5225
5 5200
N
0.
c 5175
c 5150
E 5125
0
� 5100
m 5075
m
a
`o
5050
Z
m
a 5025
a
5000
4975
The data shows an increase of reservoir pressure during 2015. The average Northstar field reservoir pressure for
2015 is 5,128 psia, up 41 psia from the 2014 average. Please note that the reported reservoir pressure of the well
NS -08 during 2015 is from the Kuparuk Reservoir.
D. Results and Analysis of Production and Iniection In- surveys, tracer survevs, observation well
surveys and any other special monitoring
No new production profiles were obtained in 2015.
The gas tracer program, initiated in 2004, was concluded in 2008 and there are no further updates for this
reporting period.
E. Review of pool production allocation factors and issues over the prior year
Theoretical production is calculated for each Northstar producing well on a daily basis.
2015 Production Allocation Method
A well's theoretical production is calculated using metered field volumes and hours on production as follows:
Gas Allocation
Gross Produced Gas = total return metered at test separator.
Page 4
Net Produced Gas = Gross Produced Gas - Goslii t Gas.
Theoretical Produced Gas = all well tests Net Produced Gas prorated by the month.
(Proration calculation will include adjustments for shut in or downtime periods)
Field Gas Injection = metered prior to injection
Total Net Produced Gas = Field Gas Injection + Fuel Gas + Flare Gas + PPA Gas - Buy Gas
(Buy Gas = imported or Caribou Crossing acquired gas).
Total Net Produced Gas
Theoretical Produced Gas = Gas Allocation Factor
Gas Allocation Factor x Theoretical Produced Gas (individual well) = Allocated Gas (individual well).
Oil Allocation
Actual Field Oil Production = oil volume metered by LACT (sold/delivered to Northstar crude oil pipeline)
(Adjusted for BS&W, temperature, and AN gravity in accordance with API standards and BSEE regulations.)
Gross Produced Oil = total return metered at test separator.
Theoretical Well Oil Production = all well tests Gross Produced Oil prorated by the month.
(Proration calculation will include adjustments for shut in or downtime periods)
Theoretical Field Oil Production = Sum of Theoretical Well Oil Production
Field Natural Gas Liquid (NGL) Production = metered prior to commingling with oil
Actual Field Oil Production- Field NGL Production
Theoretical Field Oil Production =Oil Allocation Factor
Oil Allocation Factor x Theoretical Well Oil Production = Allocated Oil Production (individual well)
Water Allocation
Actual Field Water Production = water volume metered prior to injection disposal
Net Field Water Production = Actual Field Water Production - Metered Grey Water
Gross Produced Water = total metered at test separator.
Theoretical Well Water Production = all well tests Gross Produced Water prorated by the month.
(Proration calculation will include adjustments for shut in or downtime periods)
Theoretical Field Water Production = Sum of Theoretical Well Water Production
Net Field Water Production
Theoretical Field Water Production - Water Allocation Factor
Water Allocation Factor x Theoretical Well Water Production = Allocated Water Production (individual well).
Northstar field allocation factors for 2015 averaged 0.78 for oil, 0.94 for water and 0.96 for gas. Oil allocation
factor was low due to increased Field NGL production in winter months.
F. & G. Future Development Plans & Review of Annual Plan of Operations and Development
In 2015, Hilcorp increased unit production through well intervention projects, and other optimization
opportunities, that included the evaluation of shut-in wells for potential return to service. A full field study of the
Northstar Unit was initiated. The re -mapping of all productive horizons, well histories documented, review of
production and injection data, material balance calculations, and past engineering, geological, and geophysical
work have been studied. First attempts to build Ivishak reservoir simulation model have begun in 2015.
Projects completed during the 2015 calendar year:
• NS -22 well temporarily returned to production (March 2015) with AOGCC conditional approval.
Page 5
Vapor Pressure Analyzer installed (April 2015) on Northstar island
o Improves operator ability to refine and blend NGLs to meet pipeline specifications
NS -28 well converted to gas injection in Ivishak (May 2015).
Recomplete NS -24 to Sag testing completed (Dec 2015)
o Current perforations are low perm or damaged.
o Well will naturally flow (slugging) only 5-10bfpd into depressurized separator.
o Produced 49.5API gravity oil during temporary flow test
Projects Postponed during the 2015 calendar year:
o NS -18 Kuparuk recompletion delayed until Q3 2016 due to rig limitations.
In 2016, Hilcorp will pursue increased unit production through additional well intervention projects, any necessary
infrastructure and facility repairs, and other optimization opportunities as they arise.
No drilling activities are planned at Northstar within the 2016 calendar year.
The mobilization of a workover rig to the Northstar Island during the 2016 summer barging season is currently
planned for the NS -18 recompletion to Kuparuk project.
Projects Planned for the 2016 calendarvear:
• Fix surface casing leak in the NS -22 well.
• Adperf/Reperf Ivishak with indications of scale in the NS -05 well.
• Reperforate Ivishak with indications of scale in the NS -11 well.
• Reperforate Ivishak with indications of scale in the NS -30 well.
• Reperforate Ivishak with indications of scale in the NS -34A well. (Fido PA)
• Abandon the Ivishak reservoir in the NS -18 and recomplete to the Kuparuk sand;
• Convert NS -13 into a gas injector in the Ivishak reservoir. This project will reduce injection pressure in the
field and allow for compressor horsepower optimization.
Hilcorp will progress the full field study of the Northstar Unit. This may include re -mapping potentially productive
horizons, updating well histories, reviewing all production and injection data, material balance calculations, and
reviewing results of well intervention projects in 2015/2016. Continued development of a reservoir simulation
model will be pursued, beginning with the Ivishak reservoir.
Sincerely,
Chris Kanyer
Reservoir Engineer- Northstar
Page 6
