UNITED STATES DEPARTMENT OF THE INTERIOR
MINERALS MANAGEMENT SERVICE
GULF OF MEXICO OCS REGION

NTL No. 99-G09
Effective Date:  May 10, 1999

NOTICE TO LESSEES AND OPERATORS OF FEDERAL OIL, GAS, AND SULPHUR
LEASES IN THE OUTER CONTINENTAL SHELF, GULF OF MEXICO OCS REGION

Location of Choke and Kill Lines on BOP Stacks

This Notice to Lessees and Operators (NTL) supersedes the Letter to Lessees and Operators, dated November 17, 1994, on this subject. It updates regulatory citations and includes a statement on the Paperwork Reduction Act of 1995.

The purpose of this NTL is to specify the location of the choke and kill lines serving blowout preventer (BOP) stacks. This is necessary because the requirements at 30 CFR 250.406 (oil and gas drilling operations), 250.515 (oil and gas well-completion operations), 250.615 (oil and gas well-workover operations), 250.1610 (sulphur drilling operations), and 250.1624 (sulphur well-completion and well-workover operations) do not specify their exact location.

Operators usually install the choke and kill lines above the bottommost ram. However, some operators have requested to install them below the bottommost ram. For choke lines, this is not acceptable. Failure of a choke line installed below the bottommost ram could result in a blowout because this configuration does not provide a backup system for proper well control.

Therefore, the Gulf of Mexico OCS Region District Offices will not approve an Application for Permit to Drill (APD) or a Sundry Notice and Report (Sundry) to conduct well-workover operations that indicates a BOP stack with a choke line installed below the bottommost ram. However, they may approve your requests to install a kill line below the bottommost ram. You must include a schematic drawing of the BOP stack and choke and kill lines with any APD or well-workover Sundry if the tree is to be removed.

Paperwork Reduction Act of 1995 Statement

This NTL refers to the collection of information on forms MMS-123 and MMS-124. The Office of Management and Budget (OMB) has approved the information collection requirements for these forms and assigned OMB Control Nos. 1010-0044 and 1010-0045, respectively. This NTL does not impose additional information collection requirements subject to the Paperwork Reduction Act of 1995.

Contact

If you have any questions on this NTL, you may contact Mr. Bill Martin at (504) 736-2849.

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