Qualification Testing of Large Bore, HP Tubing Retrievable Safety Valves for Gas Wells

Over the past decade, the role of natural gas has become increasingly important in fulfilling the ever-increasing energy needs of the world. Natural Gas has not only become an integral part of the world’s energy portfolio but also offers a cleaner and more efficient fuel to help reduce carbon emissions when compared to oil. Recently, Saudi Aramco has made three major offshore, high pressure, non-associated gas discoveries. A large bore completion design was selected for these fields in order to bring these discoveries on line quickly and cost effectively. The surface controlled, sub-surface safety valve is a critical component of the asset integrity management program for these gas wells. In order to meet the requirements of completion design and reservoir pressure, the world’s first 9-5/8in 10,000psi rated TRSSSV were developed tested and qualified for these developments. As part of qualification testing, high rate slam closure testing of the TRSSSV was carried out at the Southwest Research Institute and at GL Nobel Denton facilities. The objective of the tests was to ensure that TRSSSV closes, seals and continues functioning after a slam at the highest anticipated flow velocity in the wells. Additionally, slam test results were used to design surface and subsurface components that are required to operate the TRSSSV and must be capable of withstanding the shock load produced by a slam closure. Two leading completion companies were selected to develop and provide the TRSSSVs for these projects. Both designs suffered initial failures, required significant modification, and underwent extensive tests before the final designs were successfully tested. This paper discusses the basis of design, test criterion, results and lessons learned from the slam testing of the world’s first 9-5/8in, 10,000 psi rated TRSSSV. The paper also provides an overview of the two test facilities used, their limitations, and recommendations for future tests.