Enhancing hot water flooding in hydrate bearing layers through a novel staged production method

Abstract

A method to improve the performance of hot water flooding in a hydrate bearing layer (HBL) is proposed. The development approach involves a horizontal production well completed by sliding sleeves and one vertical injection well. The horizontal section of the production well is first opened to yield a high production rate. As the gas production reduces to a certain degree, staged production from the toe to the heel is conducted by opening and closing the sliding sleeves. Subsequently, particle swarm optimization is coupled with a simulator to optimize the primary adjustable parameters. Furthermore, the proposed approach is compared with an un-staged approach and Sasaki’s approach. The results indicate that the optimal injected water temperature is 51.3 °C considering both energy efficiency and recovery. The optimal distance between the horizontal wellbore and the top of the HBL is approximately 1/3 of the reservoir thickness, and the unperforated interval of the injection well should cover the upper 2/3 of the HBL. Based on the same injected heat, the proposed approach can improve cumulative gas production by 25.6%, 14.4%, and 39.1% compared with the un-staged approach, Sasaki’s approaches 1 and 2, respectively.