聚合物溶液在高盐中低渗透油藏中的适应性——以吐哈雁木西油田为例

Reservoir Adaptability of Polymer Solution in High Salinity and Mid-low Permeability Reservoirs——Taking Yanmuxi Oilfield of Tuha as an Example

陈 超 张立东 尹玉川 王崇先 卢祥国 吕金龙 王 威 闫 阳

CHEN Chao ZHANG Lidong YIN Yuchuan WANG Chongxian LU Xiangguo LYU Jinlong WANG Wei YAN Yang

吐哈雁木西油田为高盐中低渗透油藏，目前已经进入特高含水率开发阶段。为提高该油田的采收率，以油田储层地质特征和流体性质为模拟对象，开展了聚合物溶液油藏适应性研究。结果表明，聚合物相对分子质量和浓度对聚合物溶液与岩心的配伍性均有影响。当聚合物质量浓度为300~900 mg/L、相对分子质量为800×104~2000×104时，聚合物溶液对应的渗透率极限范围为20×10-3~70×10-3μm2。在聚合物相对分子质量一定时，随聚合物浓度增加，渗透率极限增加，聚合物分子线团尺寸Dh呈指数型增加；在聚合物浓度一定时，随聚合物相对分子质量增加，渗透率极限和Dh增大。由渗透率极限岩心孔隙半径中值与Dh间的关系可以得到对应的配伍区和堵塞区。对于雁630区块，油层累积厚度比达到60%时对应的储层渗透率为60.5×10-3 μm2，采用相对分子质量1700×104和900 mg/L聚合物溶液可以满足进入规定储层厚度的要求。若采用相对分子质量较低的聚合物，则聚合物浓度需相应提高。图9表2参22

Yanmuxi oilfield of Tuha is a high salinity and mid-low permeability reservoir，which has entered the stage of ultra-high water cut development. In order to improve the oil recovery of the oilfield，the adaptability of polymer solution and reservoir was studied by taking the geological characteristics and fluid properties of the reservoir as the simulation object. The results showed that the relative molecular weight and concentration of polymer affected the compatibility of polymer solution and core. When the mass concentration of polymer was 300—900 mg/L and the relative molecular weight was 800×104—2000×104，the permeability limit of polymer solution was 20 × 10-3—70 × 10-3μm2. When the relative molecular weight of polymer was fixed，the permeability limit increased with the increase of polymer concentration，and the molecular thread size（Dh）increased exponentially. When the polymer concentration was constant，the permeability limit and Dh increased with the increase of polymer molecular weight. According to the relationship between the mid value of core pore radius and Dh，the corresponding compatibility area and plugging area could be obtained. For Yan630 block，the reservoir permeability was 60.5×10-3 μm2 when the percentage of cumulative reservoir thickness reached 60%. The requirement of entering the prescribed reservoir thickness could be met by using polymer solution with relative molecular weight of 1700×104 and concentration of 900 mg/L. If the polymer with lower molecular weight was used，the polymer concentration should be increased accordingly.

10.19346/j.cnki.1000-4092.2019.04.021