Pressure On-Demand - Hybrid Electric BOP Control Systems

Abstract

Changing well control requirements have increased accumulator volumes for the operation of Blow Out Preventer (BOP) stacks and diverters, challenging the space available for the BOP control system equipment on today's rigs. Koomy or Land Closing Units (LCUs) use potential energy stored in accumulators to control the hydraulically actuated BOP Stack and diverter systems. Accumulator systems are limited in their operational capacity because of the inefficiencies created by rapid adiabatic gas expansion and the pressure and flow decay over the function stroke. By changing the approach from stored energy in accumulators to energy on-demand, the hybrid electric BOP control system will expand the operational capacity drilling rigs. The implementation of a hybrid-electric pressure on-demand BOP control system can reliably address this challenge by providing indefinite usable volume and a more reliable platform with a smaller footprint and value-added performance. Feedback loops will provide on demand flow to better match the operation and shear curves of the individual functions, eliminating the BOP closing time and response constraints that challenge traditional accumulator systems. This paradigm shift will remove the usable volume constraint as the pump on-demand system provides an indefinite amount of flow at the maximum rated working pressure of the operating piston.