Enhancing Reliability of Hydraulic Power Units in Offshore Gas Facilities: A Novel Approach of Innovative Design and Sustained Reliability

Abstract The offshore oil and gas industry encounters several challenges, particularly when it comes to ensuring the reliability of Hydraulic Power Unit (HPU) unit that play a crucial role in providing clean hydraulic oil power for the purpose of critical valves actuation, including Christmas trees (Xmas), High Integrity Pressure Systems (HIPS) and boundaries Shutdown Valves (ZV) either locally or remotely. The concern comes from the magnitude of the growth in the unmanned offshore gas facilities, mainly Wellhead Platform (WHP) and the associated challenge of operating big bore producer wells. This design utilizes multiple Hydraulic Power Units (HPUs), which consumes significant resources in terms of cost, time, and effort. The current setup promotes optimization efforts, leading to a redesign that centralizes the HPU and integrates additional features. Centralizing the HPU reduces the risk of single-component failures that could potentially halt production. One of the major concerns in HPU operation is maintaining the quality and cleanliness of hydraulic oil since the oil contamination leads to elastomer seal failures in the valves with severe impact on HIPS, HIPS as SIS (safety Instrumented System) is the ultimate overpressure protection that performs as High-class of Safety Instrumented Function (SIF). To overcome this issue, a revolutionary method has been developed, incorporating a state-of-the-art hydraulic oil flushing recirculation system paired with real-time oil monitoring. This mechanism works by continuously and remotely thru Supervisory Control And Data Acquisition (SCADA) by circulating hydraulic oil for predetermined intervals, with the duration adjusted based on the desired level of oil cleanliness. Typically, the system maintains oil purity within strict limits as per international standards, ensuring the hydraulic oil remains suitable for reliable valve operation. An additional key feature of this novel design is the employment of mechanically driven intensifier pumps instead of traditional high-pressure Alternative Current (AC) driven hydraulic pumps. These intensifiers efficiently transform low-pressure hydraulic oil into high-pressure output to operate Tubing Retrievable Sub Surface Safety Valves (TRSSSV) of the wells, resulted in higher wells availability as well as energy saving. The design is undertaken significant steps to guarantee continuous hydraulic oil power, even during instances of field power outages or planned major maintenance activities. This is accomplished by integrating a built-in Direct Current (DC) driven pump, supplemented by an independent Uninterruptible Power Supply (UPS) system. The UPS provides backup power for several hours in the event of Alternating Current (AC) power loss. The implementations of the adapted HPU design produces outstanding outcomes in unmanned offshore gas facilities. The system consistently displays significant reliability improvements, resulting in substantial cost savings measured in millions of dollars over the field's operational lifespan. These monetary advantages originate from reduced OPEX on High Integrity Pressure Protection System (HIPS) repairs, shorter production downtime durations, and decreased maintenance costs.