A Plan Regarding High Concentration Of Oil Flooding In The Major Reservoirs In Sazhong Developing Area

Through 50 years'exploration in polymer flooding technology, this technology has been widely used and becomes an important method used for substantial development in in Daqing Oilfield. The experiments and application in polymer flooding field show that the increase of recovery factor is only about 12%. The increase using asp flooding solution can reach to 20%. However, this technique is complex and requires large investment. The research results of a number of research groups show that, As a result, this leads to recovery factor of polymer flooding increases about 20% on the basis of water flooding.In order to explore the new technology used for the increase of recovery factor in a certain oil reservoir, Sazhong Developing Area has performed several experiments in the major reservoirs in west part of Middle Area and east part of South-1 Area. On the basis of indoor research of the effects on high concentration of oil flooding, we have understood the mechanism of high concentration of different flooding, as well as the features of their effects and variations. With these understandings, a plan regarding whole high concentration of oil flooding will be designed. Through the comparison between a 250m and 125m grid in east well of South-1 Area, we have got further knowledge about sedimentary units'sand body distribution and scale. We also get qualitative analysis about river sand connectivity, permeability distribution, features of interplay layers, and rhyme development. After analyzing the distribution of remaining oil, we can get a full view on this area's geological condition and summarize the production effect on the stage of blank water flooding.Indoor core oil flooding experiment was performed to test the effects of different polymer volume, different slug combination and different production time. The results show that the larger polymer volume, the higher recovery factor. Recovery factor can reach to its peak value if high concentration polymer is first injected in slug combination. According to the comparison among different stages of injection time: early stage, middle-earlier stage, middle-later stage, and late stage, we realize that the earlier injection of high concentration polymer, the higher increase of recovery factor. Combining the experience and method in major oil layer in Daqing Oilfield, the polymer injection parameters, such as polymer injection weight, injection concentration, and injection velocity, have been carefully designed to increase the recovery factor in oil field. Pressure space and PV relationship charts are drawn to calculate high concentration slug volume in single wells, which prove that every station can inject high concentration slug with different slug volume in different station. 35 million ultra-high grid previa slug should be applied to adjust before polymer injection. Through increase in polymer concentration and layer polymer injection, the recovery factor in the central well can increase by 22% with total recovery factor increasing by 60%.