Maximizing Steam Distribution Performance to Prevent Forced Steam Release in a Steam-flooded Oil Field

Abstract

Abstract The significant decline of steam generation and distribution demand from 1.3 million barrels of steam per day (BSPD) down to 300-400 MB SPD has reduced steam velocity that triggered the condensation at the end of steam corridors that potentially caused facility integrity issue, mainly corrosion in steam-flooded Duri Field, Indonesia. Starting 2014, this issue has become a concern, and it was addressed by maintaining steam flow at the end of the corridors. The solution was to maintain the injector located the end of corridor (EOC) active, at least injecting steam at 45 barrels steam per day (BSPD), or if there was no active injector at the end of the corridor then the steam must be blown down to atmosphere, which resulted in significant steam waste while the steam constitutes of 40% total operational expenses in steam flood recovery. A total of 137 steam blowdown sites were identified with a total estimated continuous steam waste of 35,000 BSPD. In average, each site releases steam rate of 260 (BSPD). The strategy to eliminate this steam waste involved integrated evaluation of steam line configuration and active steam injector location. Based on this condition, the resolution to stop steam blowdown would require either reactivating idle or broken steam injector or installing isolation valve. Out of these 137 sites, 47 sites should be resolved by injector reactivation while the remaining 90 sites should be resolved by isolation valve installation. The steam injector reactivation was started in February 2021 and completed in October 2022. It resulted in steam saving of 12.5 MB SPD. Steam saving has been used to fund the 2022-2023 steam redeployment program that resulted in an increase of 10% oil production in 2022 and 25% in 2023 in the targeted patterns. Meanwhile, the installation of isolation valve is currently in progress. Eighty of the 90 blowdown sites were already closed after installation of isolation valve from October 2021 that resulted in steam saving of 19 MB SPD. This steam saving will play an important role in supporting the steam optimization program where fuel gas supply remained a constraint at that time. The efforts to eliminate steam blowdown described above have become a standard for steam flood operation especially in Duri Field. Steam corridors would need to either maintain the last injector downstream of the line with injection rate at least 45 BSPD or have an isolation valve installed if it has extension downstream of that injector. This operational design has contributed to conservation of energy safely and preservation of the surface facilities integrity.