Expro Sets Record with its Electro-Hydraulic Subsea Tree in
The Expro Group successfully deployed its electro-hydraulic EXpress Deepwater Subsea Test String in a water depth of 6,693ft during recent well testing operations on BP's Plutao 1a Well in Block 31 offshore Angola. The EXpress system was deployed, operated and retrieved successfully during the 6-day test on the Leiv Eiriksson DP vessel in August 2002.
The Expro Group specifically developed its EXpress technology to meet the stringent safety and operational requirements of deepwater applications. As Operators exploit ever increasing water depths, traditional direct hydraulic controlled subsea systems are unable to deliver the system shut-in and disconnection response times required to match dynamically positioned drilling vessels. The EXpress system combines Expro's field proven Deepwater Vent Pack (DWVP) technology with an electro-hydraulic control system to deliver superior response performance.
The EXpress control system offers a number of advantages over conventional hydraulic systems, the primary one being depth independence. An electrical signal is used to activate the subsea system, thus removing the inherent depth time lag associated with hydraulic systems.
During the operation, full emergency disconnect trials were conducted using the primary electrical system controlled from the driller's remote unlatch switch and the main Surface Electrical Control Panel (SECP). Trials using both stations resulted in controlled shut-in and disconnection times of 9 seconds. In comparison, conventional hydraulic actuation would normally take around 90 seconds to complete this cycle.
This is the latest in a comprehensive series of deepwater testing operations Expro has conducted for major Operators in West Africa since the mid 1990s. Expro has completed over 35 Drill Stem Tests (DSTs) to date, using its deepwater subsea strings. The EXpress system is scheduled to complete further deepwater well testing operations for ChevronTexaco and bp offshore Angola later this year.