The trend in the North Sea has been toward installing annular safety valve (ASV) systems for tension leg platform (TLP) completions or for gas-lifted platform production wells. To satisfy the requirements for a highly reliable annular safety system for the Norske Shell Draugen project and an impending Norwegian TLP completion project for the North Sea area, tests were initiated to investigate the feasibility of a polished bore receptacle (PBR)-based ASV system. The nipple system has the capability to handle high hang-weight and/or thermally-induced loads, and the PBR nipple, pre-installed in the casing string, will permit a variety of completion designs that can be determined later in the welldevelopment cycle. Testing verified that 1) only a minimal pressure drop occurred through the system, 2) there were no compatibility problems between drilling/cementing operations and the PBR system, and 3) a PBR casing nipple assembly to anchor an ASV system has the capability to provide a viable alternative to use of a mechanical ASV packer and its related seals.

Keywords:
safety valve, nipple assembly, cement, packerless annular safety valve, pressure drop, primary design consideration, hanger, asv system, pbr, completion equipment
Subjects:
Safety, Completion Selection and Design, Completion equipment
Copyright 1993, Society of Petroleum Engineers
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