STATE OF ALASKA

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

THE REQUEST OF UNION OIL COMPANY OF       )  Disposal Injection Order No. 10
CALIFORNIA (UNOCAL) to dispose of         )
Class II fluids by underground injection  )  Granite Point Field
in the Granite Point Well 44-11           )  Granite Point 44-11 Well
                                          )

                                             June 16, 1995
IT APPEARING THAT:

1. UNOCAL by correspondence dated April 6, 1995 made application to the Alaska Oil and Gas Conservation Commission (AOGCC) for authorization to inject Class II waste fluids into the Granite Point No 44-11 well.

2. Notice of an opportunity for public hearing was published in the Anchorage Daily News on April 13, 1995.

3. No protest or request for public hearing was received.

FINDINGS:

1. UNOCAL is the operator of the Granite Point Field.

2. Two wells, Granite Point No. 31-14 RD2 and Granite Point MUCI-2, penetrate the proposed injection zone within a one-quarter mile radius of the Granite Point No 44-11 well (GP 44-11).

3. Granite Point No. 31-14 RD 2 has 13-3/8" casing set at 2106' (subsea) cemented with 1100 sacks of cement and 9-5/8" casing set at 4344' (subsea) cemented with 675 sacks of cement.

4. Granite Point MUCI-2 has 13-3/8" casing set at 3788' (subsea) cemented with 642 sacks of cement and 9-5/8" casing set at 8297' (subsea) cemented with 600 sacks of cement.

5. UNOCAL proposes to monitor the 9-5/8" by 13-3/8" annulus pressure in Granite Point wells No. 31-14 RD 2 and MUCI-2 on a daily basis during injection operations, to ensure the wells do not function as conduits for fluid migration.

6. Mobil Oil Company and UNOCAL are surface owners within a one-quarter mile radius of GP 44-11 and have been duly notified of the proposed plans.

7. GP 44-11 was drilled to a total measured depth of 12208', equivalent to 11343' true vertical depth.

8. UNOCAL proposes to plug back the GP 44-11 well to 7800' measured depth.

9. The Upper Tyonek Formation is present within the GP 44-11 wellbore from the proposed plug back total depth to above 3000' measured depth.

10.The Upper Tyonek Formation consists primarily of interbedded siltstone, mudstone, coal, and lenticular sandstone. The sandstones, in general, are laterally discontinuous and comprise a low volume formation. Impermeable lithologies dominate the Upper Tyonek Formation.

11.Sandstones that are continuous throughout the vicinity of the GP 44-11 wellbore are present in the 4380'-4500', 5100'-5500', and 5900'-6300' measured depth intervals.

12.The proposed disposal injection zones are in the 5100'-5500', and 5900'-6300' measured depth intervals in the GP 44-11 wellbore.

13.The portion of aquifers beneath Cook Inlet described by a one quarter-mile area beyond and lying directly below the Granite Point Field are exempted for Class II injection activities by 40 CFR 147.102(b) (2) (A) and 20 AAC 25.440 (c).

14.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 that surpass those expected for the GP 44-11 project, indicates induced fractures can not propagate more than 1100 feet vertically.

15.The disposed fluids are anticipated to be contained below a true vertical depth of 3850' within the Upper Tyonek Formation, based on worst-case fracture modeling.

16.In well GP 44-11, 13-3/8" surface casing string is set at 4019' measured depth and cemented with 2400 sacks of cement.

17.Nine and 5/8" casing is set at 7962' measured depth and cemented with 1800 sacks of cement.

18.UNOCAL proposes to install a string of 3-1/2" tubing with a packer set at 5030' measured depth.

19.UNOCAL proposes to run cement and casing evaluation tools in GP 44-11 to evaluate if the well can be successfully converted for disposal operations within the proposed disposal intervals.

20.Disposal fluids will consist of fluids associated with drilling, production, and workover operations. Typical fluids will include produced water, drilling and completion fluids, equipment wash water, drilling mud and cuttings, and NORM scale.

21.Maximum injection rate is expected to be 3000 barrels per day.

22.Estimated average injection pressure will be 2498 psi and estimated maximum injection pressure will be 3500 psi.

23.UNOCAL plans to monitor the 9-5/8" by 13-3/8" casing annulus pressure of the GP 44-11 during injection operations and report results on the Monthly Injection Report.

CONCLUSIONS:

1. The approval of disposal injection operations at GP 44-11 will not jeopardize correlative rights.

2. Permeable strata that reasonably can be expected to accept injected fluids at pressures less than the fracture pressure of the confining strata are present in the interval from 5120' to 7800' measured depth in GP 44-11.

3. All USDWs in the Granite Point Field have been exempted for Class II injection activities.

4. Injected fluids likely will be contained below a true vertical depth of 3850' adjacent to the GP 44-11 wellbore.

5. Fluids injected at GP 44-11 will consist of Class II waste generated from drilling, completion, and production operations.

6. Mechanical integrity of the tubing, packer and 9-5/8" casing must be demonstrated in GP 44-11 prior to commencing injection operations, in accordance with 20 AAC 25.412.

7. Annulus pressure monitoring of GP 44-11 and surrounding wells is appropriate.

NOW, THEREFORE, IT IS ORDERED THAT:

Rule 1 Authorized Injection Strata for Disposal.

Class II oil field fluids may be injected in conformance with Alaska Administrative Code Title 20, Chapter 25, for the purpose of disposal into the Tyonek Formation interval from 5120' to 7800' measured depth in well GP 44-11.

Rule 2 Demonstration of Tubing/Casing Annulus Mechanical Integrity

The tubing/casing annulus must be tested prior to injection and every four years thereafter for mechanical integrity in accordance with 20 AAC 25.412. UNOCAL must demonstrate GP 44-11 contains sufficient volume of cement and/or adequate cement bond and mechanical integrity in accordance 20 AAC 25.030 and 20 AAC 25.412 prior to initiation of injection operations.

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 Annulus Pressure Monitoring

The 9-5/8" by 13-5/8" annulus pressure in Granite Point wells 44-11, 31-14 RD2 and MUCI-2 will be monitored daily during injection operations and reported monthly on the "Monthly Injection Report" AOGCC form 10-406.

Rule 5 Administrative Action

Upon request, the Commission may administratively revise and reissue this order upon proper showing 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 June 16, 1995.

David W. Johnston, Chairman

Russell A. Douglass, Commissioner

Tuckerman Babcock, Commissioner

Dispose Injection Order Index