First Application of Intelligent Gas Lift System in ADNOC Offshore Field to Improve Profitability Through Enhanced Gas Lift

Abstract

Gas lift is one of the most crucial components for achieving and maintaining the production targets in a giant offshore oil field development. All producer wells are completed with gas lift mandrels (GLMs) using both dummy and tubing pressure shearable valves to accelerate and enhance efficiency of the initial unloading and gas lift start up. The gas lift designs are optimized considering reservoir conditions and surface constraints over the well life cycle. However, once the GLMs are installed, the gas lift optimization would require intervention work, hence production interruptions. To maximize the gas lift performance and minimize the intervention work, a digital intelligent gas lift (DIAL) system was trialed. Once the system was selected, a comprehensive design review was conducted covering product qualification, material suitability, factory acceptance testing, and technical limits in both initial installation and well life cycle operation. Detailed pre-installation preparation such as system integration testing and installation procedures were prepared. Four DIAL units were installed successfully in a record extended reach drilling (ERD) well together with 4 conventional GLMs along with dummy valves, as contingency. The system was successfully tested during nitrogen unloading operations which not only demonstrated the functionality of the equipment, but also the increased efficiency of the use of the system. It is estimated that the use of DIAL in this pilot well will result in substantial net present value generation based on the elimination of well intervention related cost to service gas lift valves, avoidance of production deferral, and production gain resulting from optimized real time gas lift operations. Each DIAL unit has built-in pressure and temperature sensors and adjustable size orifices. This allows the operator to manage the evolving well and reservoir conditions by applying data driven decision making and surface control during well unloading and production to enable the optimum gas lift injection rate and depth to maximize production. This is all able to be accomplished without the need of wireline intervention for valve change out. This process is repeated until gas reached the deepest valve. Additional benefits of using DIAL system in gas lift operations, as compared to conventional systems, will be described in the paper. The first DIAL system was installed in one of the top 10 globally longest ERD wells containing the largest DIAL system ever mounted. The paper will describe the brief history of artificial lift strategy for the field and current practices, drivers for trialing DIAL, the equipment qualification process, installation overview, and finally ultimate benefits seen in the initial unloading and gas lift operations.