STATE OF ALASKA

OIL AND GAS CONSERVATION COMMISSION
3001 Porcupine Drive
Anchorage, Alaska 99501-3192

Re:	The REQUEST OF UNION OIL	        )  Disposal Injection Order No. 9
COMPANY OF CALIFORNIA)
(UNOCAL) to dispose of Class II                 )
oil field fluids by underground                 )  Kenai Unit No 11-17 well
injection in the Kenai Unit 11-17 well.         )  Kenai Unit

                                                   November 16, 1994

IT APPEARING THAT:

1. Unocal by correspondence dated October 3, 1994 made application to the Alaska Oil and Gas Conservation Commission (AOGCC) for authorization to inject Class II waste fluids into the Kenai Unit No 11-17 well.

2. Notice of an opportunity for public hearing was published in the Anchorage Daily News on October 13, 1994.

3. No protest or request for a public hearing was filed.

FINDINGS:

1. No wells penetrate the proposed injection zone within a one-quarter mile radius of the Kenai Unit No 11-17 well (KU 11-17).

2. Cook Inlet Region Inc. and Salamantof Village are surface owners within a one-quarter mile radius of the KU 11-17 and have been duly notified of the proposed plans.

3. Unocal is the operator of the Kenai Unit. There are no other operators present within a one-quarter mile radius of the proposed KU 11-17 disposal injection project.

4. KU 11-17 was drilled to a total measured depth of 5400 feet, (4861 feet true vertical depth).

5. The Sterling Formation consists of Pliocene aged, massively bedded, predominately coarse grained, fluvial deposits and is present within the KU 11-17 from approximately 500 feet measured depth to total depth.

6. The proposed disposal injection zone is 4468 to 5152 feet measured depth (approximately 3970 to 4570 feet vertical subsea) in KU 11-17.

7. All aquifers below 1300 feet within the Kenai Gas Field Boundary, and one-quarter (1/4) mile beyond, are exempted under 40 CFR 147.102(b)(1)(C).

8. Approximately 2738 true vertical feet of Sterling Formation sediments separate the proposed disposal injection zone in KU 11-17 from the base of the non-exempt aquifers in the Kenai Unit. This interval contains an aggregate thickness of approximately 500 true vertical feet of impermeable confining zone lithologies.

9. Thirteen and 3/8-inch surface casing string is set at 1994 feet measured depth, cemented to the surface and tested to 2500 psi.

10. Nine and 5/8-inch casing is set at 5371 feet measured depth, cemented to at least 3000 feet measured depth and tested to 3000 psi. Cement evaluation tools run in KU 11-17 indicate good to excellent cement bond from total depth to 3000 feet measured depth.

11. Two strings of three and 1/2-inch tubing are installed with dual packers set at 4351, 4508, and single packers set at 4620 and 5003 feet measured depth.

12. The operator conducted a mechanical integrity test on KU 11-17 on 6/10-11/94. Test pressure declined 12 psi in 24 hours from 1000 psi to 988 psi.

13. Disposal fluids will consist exclusively of fluids brought to the surface as a result of drilling, production, and workover operations. Typical fluids will include produced water, drilling and completion fluids, equipment wash water, drilling mud and cuttings, and pipe scale.

14. Maximum injection rate is expected to be 3000 barrels per day. Average injection rate is estimated to be 50 to 100 barrels per day.

15. Estimated average injection pressure will be 1000 psi. and maximum injection pressure will be 2400 psi.

16. The estimated injection pressure parameters for KU 11-17 are based on step rate tests performed in two other Class II, Sterling Formation disposal wells within the Kenai Unit.

17. A three-dimensional hydraulic fracture simulator run of a worst-case scenario with injection pressures exceeding the anticipated formation parting pressure, and using volumes of drill cuttings which surpass those expected for the KU 11-17 project, indicates induced fractures will not propagate through the overlying confining zones and cause a risk of contamination to non-exempt aquifers.

18. The operator plans to monitor the 9 5/8-inch casing by 3 1/2-inch tubing annulus pressure and report the results on the Monthly Injection Report.

CONCLUSIONS:

1. KU 11-17 is constructed in conformance with the requirements of 20 AAC 25.412.

2. Well integrity has been demonstrated in KU 11-17 in accordance with 20 AAC 25.412.

3. There is sufficient impermeable confining zone lithologies present in KU 11-17 between the top of the proposed disposal injection zone and the base of the deepest non-exempt aquifer to prevent injection fluid from entering any underground source of drinking water.

4. Disposal injection operations in the KU 11-17 will be conducted routinely at pressures less than confining zone parting pressure and will not initiate or propogate fractures through the confining zones.

5. The requirements of 20 AAC 25.252 have been met.

6. The approval of disposal injection operations at KU 11-17 will not jeopardize correlative rights.

NOW, THEREFORE, IT IS ORDERED THAT:

Rule 1 Authorized Injection Strata for Disposal.

Class II fluids may be injected in conformance with Alaska Administrative Code Title 20, Chapter 25, for the purpose of disposal into the Sterling Formation interval from 4468 to 5152 feet measured depth in KU 11-17.

Rule 2 Demonstration of Tubing/Casing Annulus Mechanical Integrity

The tubing/casing annulus must be tested every four years for mechanical integrity in accordance with 20 AAC 25.412.

Rule 3 Well Integrity Failure

Whenever disposal rates and/or operating pressure observations or pressure tests indicate pressure communication or leakage of any casing, tubing or packer, the operator must notify the Commission on the first working day following the observation, obtain Commission approval of a plan for corrective action and obtain Commission approval to continue injection.

Rule 4 Administrative Action

Upon request, the Commission may administratively revise and reissue this order if convinced that any changes are based on sound engineering practices and will not result in an increased risk of fluid movement into an underground source of drinking water.

DONE at Anchorage, Alaska and dated November 16, 1994.

David W. Johnston, Commissioner

Russell A. Douglass, Commissioner

Tuckerman Babcock, Commissioner

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