Technology advancements have enabled our clients to explore and appraise fields with wellhead shut-in pressures in excess of 10,000 psi in deep water environments.  The drive to develop these fields has resulted in the introduction of subsea control systems for completion and intervention operations for High Pressure (HP) applications.  Based upon the experience gained of operating of similar systems at standard pressures, Expro developed large bore high pressure subsea systems (EXPRESS-HP) capable to deploy completions and conduct interventions in up to 10,000 ft of water.  These systems do not only control the Expro Landing String Assembly (ELSA), but also operate and monitor all downhole functions for the tubing hanger, tubing hanger running tool, subsurface safety valve and other completion equipment.

The increased water depth has resulted in the use of dynamic positioned vessels during these operations which require a faster system response than what could be obtained with direct hydraulic systems.  In addition the handling of the umbilical and reeler units, on land and offshore, that would be required in direct hydraulic mode in water depths over 6,000 ft, can not be easily achieved.

The EXPRESS-HP system provides our clients with the functionality required to operate under these conditions in wells up to 15,000 psi.  The subsea control system operates all functions Electro-Hydraulically and provides a separate multiplex data acquisition package which operates completely independent from the ‘simplex’ control system, thereby optimising system reliability.  Full system redundancy is as a minimum provided on all safety critical functions. Another key benefit to the Expro ‘simplex’ Express system is the unique hydraulic over-ride function in the event of an electrical failure.  This allows the operation and control of the safety critical functions thus ensuring a full system disconnect can still be achieved at all times.