Philip M. Ayer
Advising Petroleum Engineer
P. O. Box 196247
Anchorage, Ak 99501
Re: The application of Union Oil Company of California to inject approved wastes from the Dillon Platform for the purpose of disposal into the stratigraphic interval authorized for enhanced recovery by Area Injection Order No. 8.
Dear Mr. Ayer:
On January 29, 2003, Unocal was granted approval to dispose of approved wastes developed during the cleaning of the production vessels and wells on Dillon Platform into Dillon wells Di-12 and Di-14. Please reference Administrative Approval No. AIO 8.2.
Unocal has submitted sundry approval requests for the identified wells and the specific approval for Di-12, 303-021 was given on January 29, 2003. As the approval for Di-14 was processed, it was brought to the Commission’s attention that “deck drainage” resulting from rain and snow falling on the platform was a fluid that might also require disposal.
Rule 9 of Area Injection Order No. 8 allows the Commission to administratively amend any rule in the order as long as the operator demonstrates to the Commission’s satisfaction that sound engineering practices are maintained and the amendment will not result in an increased risk of fluid movement into an underground source of drinking water.
The Commission has previously found that storm water collected in the drain system of another platform was suitable for disposal in a Class II-D well (DIO 22.001, June 19, 2002). Unocal has previously demonstrated Dillon Platform wells Di-12 and Di-14 have mechanical integrity suitable for disposal injection operations. In this particular case, deck drainage fluids had not been specifically identified in AIO 8.2, however, the Commission did not specifically intend to exclude such fluids from the disposal authorization. Adding deck drainage to the previously approved disposal fluids in these wells will not adversely impact the reservoir or present any increased risk to the environment.
The portion of aquifers beneath Cook Inlet described by a ¼ mile area beyond and lying directly below the middle Ground Shoal Field are exempted for Class II injection activities by 40 CFR 147.102(b)(2)(B) and 20 AAC 25.440(c).
Pursuant to Rule 9 of Area Injection Order No. 8 deck drainage is an authorized fluid for disposal in Dillon Platform wells Di-12 and Di-14 within the MGS A, B, C, D, E, F, and G Oil Pools. The total volume authorized for disposal by AIO 8.2 remains 50,000 barrels.
DONE in Anchorage, Alaska this 4th of March 2003.
Daniel T. Seamount, Jr.
BY ORDER OF THE COMMISSION