Increasing hydraulic power subsea: A comparison of economies and capabilities of available and emerging technologies which promise to supply greater hydraulic energies to high pressure BOP control equipment

摘要

Recent tragic events in the Gulf of Mexico have highlighted the need for subsea technologies which can reliably supply hydraulic fluid at higher pressures and volumes than in conventional systems. These newer solutions are necessary in order to increase actual shearing capacity of subsea BOPs. Although the incident at the Macondo well was apparently primarily the result of multiple human errors, operators are now also rushing to increase the shearing capabilities of critical BOP equipment and reduce perceived weaknesses in the subsea systems. These functions allow automatic and manually operated shearing through various tubulars in order to seal the well and contain high pressure well products and mud inside the pressure barrier and under control. Solutions which are compact, highly capable, and rugged are required. At a high level capital investment, time to market, and operational capability each play into the decision making process for all drilling contractors. Rig-specific factors such as planned drilling depth, stack weight, existing architecture, and available topside real estate must also be taken into consideration when determining the optimal method for achieving higher shearing capabilities. The authors will present a simplified version of available and emerging technologies which promise to increase the amount of usable fluid at the required operating pressure for shearing subsea. These include subsea intensification, top off systems with flexible auxiliary hoses, rigid conduit systems, and unconventional subsea hydraulic fluid accumulation. The discussion includes explanation of common terms and their proper use as well as new system specifics which have recently come under closer scrutiny. Then each solution will be compared on its merits and an optimal choice will be designated for use on each of three hypothetical drilling rigs.