Numerical Simulation Research On The Injection Pattern Of High Concentration Polymer Flooding

Combining static data of X13 high concentration polymer displacement teat site and the digitized results of detailed sedimentary, corresponding tectonic model and attribute model were established by Petrel 3D geological modeling software. History matching about established geological modeling during water flooding have been made by Eclipse numerical modeling software, including oil production, water cut, liquid production capacity and recovery percent of block and single well. In addition, water injection rate, liquid production capacity, oil production and recovery efficiency of this block were also predicted under the condition of 98% water cut.Based on the history matching during water flooding, the research of high concentration polymer displacement numerical modeling were carried out. It was studied that how the concentration change of single polymer slug and multiple polymer slug effect on oil recovery efficiency, and what the role of separate zone injection and separate mass injection is in influencing oil recovery. The development effectiveness of various schemes were comparatively analyzed, and the best injection pattern of high concentration polymer flooding in test site were determined. The result shows that the setting of the first slug in multiple slug composition is of great importance. The optimal displacement efficiency will be achieved when the first slug is one third of the whole slug. The displacement effect of separate zone injection is superior to general injection, and the best separating time should be selected in the period of water cut decline. The best polymer displacement project is that polymer with a concentration of 1800mg/L which made up by 25 million high-molecular polymer should be selected and injected in the way of multiple slug when water cut begins declining.The highest recovery will be achieved when the pre-slug of high concentration is one third of the whole slug.The study will provide a theoretical guidance for field experiment of high concentration polymer flooding.