Castrol has upgraded the Sub Surface Safety Valve (SSSV) test facilities at its International Testing Facility, Pangbourne, UK, allowing subsea control fluids to be subjected to the increasingly extreme conditions found in oil and gas exploration.

In downhole completions, Castrol subsea control fluids are used to operate the SSSV, which sits in the flowing well stream and is the hottest part of a subsea system. This safety critical device acts as the final line of defense and seals the well in the event of an emergency.

Castrol’s Pangbourne facility comprises two purpose-built SSSV test rigs designed to evaluate SSSV and subsea production control fluid performance at the conditions seen in the well. This means pressures of up to 20,000psi and temperatures in excess of 200°C. These fixtures are manufactured to the guidelines as defined in OTO 99 001 and incorporate the port, actuator, piston and seals (static and dynamic), and return spring as used in SSSVs. Each fixture is specific to a particular model of SSSV. Castrol Offshore works closely with the main SSSV vendors; Baker Oil Tools, Halliburton and Schlumberger (Camco), and has completed HP/HT qualification testing with all of their current SSSV designs.

The industry standard test (API 14) requires SSSVs to be qualified under a “hot cyclic” test regime, whereby the SSSV will be cycled from open to closed and back again for typically 600 cycles. However the API test takes only a few days to complete and does not incorporate extended hold-open periods that are normally experienced in the field. The standard API test does not therefore evaluate the closing characteristics after long hold-open periods or the behaviour of SSSV materials such as elastomers and plastics over extended periods at temperature and pressure; nor does it consider the behaviour of the subsea production control fluid under these conditions.

Tags: Castrol Offshore