STATE OF ALASKA

ALASKA OIL AND GAS CONSERVATION COMMISSION

3001 Porcupine Drive

Anchorage Alaska 99501-3912
Re: THE REQUEST OF THE NORTH ) Conservation Order No. 233
SLOPE BOROUGH to present )
testimony to determine ) Barrow Gas Field
field and pool rules for ) South Barrow Gas Pool
the Barrow Gas Field ) East Barrow Gas Pool
September 30, 1987
IT APPEARING THAT:

1. The North Slope Borough, operator of the Barrow Gas Field, requested the Alaska Oil and Gas Conservation Commission by letter dated July 22, 1987 to hold a public hearing in order to receive testimony for establishment of pool rules to govern the drilling, development, and production operations for the South Barrow Gas Pool and the East Barrow Gas Pool.

2. Notice of public hearing held August 31, 1987 was published in the Anchorage Daily News on July 25, 1987.

3. A hearing covering the matter of the applicant's request was held in conformance with 20 AAC 25.540 at the office of the Commission, 3001 Porcupine Drive, Anchorage, Alaska 99501 at 9:00 a.m. on August 31, 1987.

4. Members on the staff of the North Slope Borough presented testimony including exhibits. The hearing record was closed at the end of the public hearing.

FINDINGS:

1. Gas accumulations in basal transgressive Jurassic and Cretaceous age sands occur in structural traps peripheral to an apparent diaper-like feature near the village of Barrow, Alaska.

2. Two gas accumulations near Barrow have been known as the South Barrow Gas Field and the East Barrow Gas Field from which gas is produced for local consumption.

3. From production history the East Barrow Gas reservoir shows an active water-drive, whereas the South Barrow Gas reservoir has none. The two gas accumulations do not appear to be in communication.

4. The sands in which the gas accumulations occur in the South and East Barrow Pool are lenticular in nature and irregular in occurence.

5. The vertical limits of the gas pool in the South Barrow Gas Pool and the East Barrow Gas Pool may be defined by gas sands penetrated in the North Slope Borough South Barrow No. 13 well which appears to be a typical and representative well.

6. Well spacing in the South Barrow Gas Pool was regulated by Federal agencies during early development of the pool following its discovery in 1949.

7. Well spacing in the East Barrow Gas Pool was regulated by Federal agencies during early development of the pool following its discovery in 1974.

8. Several wells have been drilled, and completed or abandoned under federal jurisdiction prior to this Order and, therefore, are not in violation of statewide regulations or this Order.

9. The Barrow Gas Field was conveyed to the North Slope Borough from the Federal government in 1984.

10.The gas wells in the South and East Barrow Gas Pools have been on production for many years, and have produced reliably and safely.

11.Barrow is entirely dependent upon the Barrow Gas Field which is the sole supply of heat and fuel for electrical generation; therefore, there are bypasses around the gas production meters which are to remain sealed except in emergencies.

12.Accumulated hydrocarbon liquids and water are purged from wells by two to three minute blowdowns of the tubing at intervals normally between one and four weeks, depending on production rate.

13.Approximately depth of permafrost in the affected area is 550 feet TVD.

CONCLUSIONS

1. It is appropriate to write field rules for the Barrow Gas Field.

2. There are two pools in the Barrow Gas Field.

3. The Barrow Gas Field has been operated safely and reliably with existing spacing, construction, and operational procedures.

NOW, THEREFORE, IT IS ORDERED THAT the rules hereinafter set forth apply to the following described area referred to in this Order as the affected area:

Umiat Meridian

T21N R16W Sections 4, 5, 6, 7, 8, 9, 16,
17, 18, 19, 20, and 21.
T21N R17W Sections 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
22, 23, and 24.
T21N R18W Sections 1, 2, 3, 10, 11, 12, 13, 14,
15, 22, 23, and 24.
T22N R16W Sections 19, 20, 28, 29, 30, 31,
32, and 33;
S 1/2 Sections 17, 18, and 21.
T22N R17W Sections 7, 8, 17, 18, 19, 20, 21, 22, 23,
24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
33, 35, and 36.
S 1/2 Sections 5, 6, 13, 14, and 15;
W 1/2 Section 9;
W 1/2 and SE 1/4 Section 16.
T22N R18W Sections 10, 11, 12, 13, 14, 15, 22,
23, 24, 25, 26, 27, 34, 35, and 36;
S 1/2 Sections 1, 2, and 3.

Rule 1. Field and Pool Name

The field is named the Barrow Gas Field. The hydrocarbons contained within the sands in the cretaceous Pebble Shale Unit and Jurassic Kingak formation constitute two reservoirs named the South Barrow Gas Pool and the East Barrow Gas Pool.

Rule 2. Pool Definition

The South Barrow Gas Pool and the East Barrow Gas Pool are defined as the accumulations of gas which are common to and which correlate with acumulations found in the North Slope Borough South Barrow No. 13 well between the measured depths of 2210 and 2472 feet.

Rule 3. Well Spacing

a) The spacing of all wells drilled and completed within the affected area prior to the date of this Order is approved.

b) Nominal 160-acre drilling units are established for the pool within the affected area of all wells to be drilled and completed subsequent to the date of this Order. Each drilling unit shall conform to governmental quarter sections. No more than one well may be drilled into and produced from each drilling unit. A pool may not be opened in a well closer than 1000 feet to any other well opened in the pool. A pool shall not be opened in any well closer than 1500 feet to the exterior boundary of the affected area or closer than 1500 feet from the boundary where ownership changes.

c) Upon application by the operator accompanied by substantiating data based on engineering and geological principles, the Commission may administratively approve modifications to well spacing.

Rule 4. Casing and Cementing Requirements

a) Surface casing to provide for proper anchorage to the surrounding formation, to prevent uncontrolled fluid flow, and to protect the well from the effects of permafrost thaw-subsidence or freeze-back loadings, shall be set at least 500 measured feet below the base of the permafrost. Sufficient cement shall be used to fill the annulus behind the casing to the surface.

b) Alternate means for maintaining the integrity of the well from the effects of permafrost thaw-subsidence ane freeze-back may be administratively approved by the Commission upon application and presentation of data which show the alternatives are appropriate, based upon accepted enngineering principles.

Rule 5. Completion Practice

Wells completed for production from the Barrow Gas Pools are to utilize casing strings or liners cemented through the production intervals. The Commission may administratively approve alternate completion methods where appropriate.

Rule 6. Gas Venting or Flaring

a) The venting or flaring of gas is prohibited except as may be authorized by the Commission for facility safety, operational necessity, and in the cases of emergency.

b) Bottom-hole accumulated hydrocarbon liquids and water may be purged from wells by periodic tubing blowdowns of brief duration.

DONE at Anchorage, Alaska and dated September 30, 1987.

Lonnie C. Smith, Commissioner
Alaska Oil and Gas Conservation Commission

W. W. Barnwell, Commissioner
Alaska Oil and Gas Conservation Commission

Conservation Order Index