A Case Study: A Successful Steam Flooding Project to Enhance Oil Recovery of Low-permeability, Light-oil Waterflooding Reservoir

摘要

Steam flooding, one of commercial technologies widely used to develop heavy oil reservoir, has brought reservoir engineer’s attention to improve performance of waterflooding, light oil reservoir and enhance its oil recovery. In Cy reservoir of Daqing oil field, a steam flooding project is successfully going on to enhance the oil recovery after waterflooding. Cy reservoir is a typical low-permeability, light-oil reservoir with depth of 1000m, an average permeability around 8 md and a typical porosity of 16%, oil viscosity of 16~95mpa.s. Cy reservoir came into development in 1995 under waterflooding. However, waterflooding has suffered from low water injectivity, poor sweep, and poor injector-to-producer communication. Only 10% of oil in place has been produced during 10 years’ waterflooding. In 2007, steam flooding was utilized to improve the performance and enhance the oil recovery. The steam flooding project shows promising results. The response to steam injection is prompt and significant. The injectivity is doubled and productivity is almost tripled. The oil-steam-ratio is around 0.3. The incremental recovery is predicted to be over 10%. The paper will firstly brief production history of waterlfooding. Secondly, the paper will detail steam injection and analyze its performance and influence factors.The paper will also discuss mechanisms, strategies as well as barriers and difficulties to high recovery of steam flooding in such waterflooding, light oil, low permeable reservoir andl also detail reservoir engineering study, such as development manner, injection and production system, and its physical and numerical simulation. The steam flooding project shows us that steam injection has great potential in improving injection and production profiles, increasing productivity and enhancing oil recovery.