古城油田B125区块稠油油藏超高分子量聚合物驱技术

古城油田B125区块普通稠油油藏储层非均质性严重，原油平均黏度达1 000 mPa·s以上，进一步提高采收率难度大。为此，通过增黏性、流变性和驱油试验，评价了超高分子量聚合物提高普通稠油采收率的技术优势，考察了含硫污水对聚合物溶液性能的影响。试验表明，超高分子量聚合物增黏性优越，相同质量浓度下较常规聚合物溶液黏度高40%以上；黏弹性强，相同黏度下较常规聚合物采收率提高3.4百分点以上；含硫污水会造成聚合物溶液黏度降低10%以上、弹性明显减弱和采收率提高幅度降低3.0百分点。B125区块部署注聚井22口，截至2018年底，累计注入0.22倍孔隙体积的聚合物溶液，注入压力上升3.5 MPa，日产油量增加45.0 t，含水率降低9.0百分点，累计增产油量1.84×104 t，阶段采收率提高1.19百分点。研究与应用表明，超高分子量聚合物驱技术可以大幅提高较高黏度普通稠油油藏的采收率。 

Ultra-High Molecular Weight Polymer Flooding Technology for Heavy Oil Reservoirs in Block B125 of the Gucheng Oilfield

Common heavy oil reservoir in Block B125 of the Gucheng Oilfield shows strong heterogeneity, and the average crude oil viscosity is above 1 000 mPa·s, which makes it more difficult to further improve oil recovery rate. Technical advantages of ultra-high molecular weight polymer in enhancing the recovery factor of common heavy oil were evaluated through viscosity, rheology and oil displacement tests. The effect of sulfur-containing sewage on the performance of polymer solution was investigated. The tests show that ultra-high molecular weight polymer has a superior viscosity increasing property, and the viscosity is more than 40% higher than that of conventional polymers at the same mass concentration, and its recovery factor is 3.4 percentage points higher than that of the conventional polymers with the same viscosity. Sulphur-containing sewage will reduce the viscosity of polymer solution over 10%, the recovery factor can be decreased by 3.0 percentage points, and elasticity will be significantly weakened. A total of 22 polymer injection wells were deployed in Block B125. By the end of 2018, a total of 0.22 PV of polymer solution was injected, and the injection pressure increased 3.5 MPa. The daily oil production rate increment was 45.0 tons and the cumulative oil production increment reached 1.84×104 t, while water cut was decreased by 9.0 percentage points and EOR was increased by 1.19 percentage points in this stage. The research demonstrates that the ultra-high molecular weight polymer flooding technology can bring a largely increased EOR of high viscosity common heavy oil reservoirs, and it can provide a new technical route and on-site basis for enhancing oil recovery in this type of reservoirs.