利用 CT技术研究裂缝性油藏改性淀粉凝胶调堵液流转向

Research of Plugging and Fluid Diversion of Modified Starch Gel in Fractured Reservoir Using CT Scanning Technology

冷光耀 侯吉瑞

LENG Guangyao HOU Jirui

针对常规方法研究裂缝性油藏封堵后液流转向过程不能观察油藏内部孔隙结构和流体运移特征的问题，运用改性淀粉凝胶封堵人工裂缝， 利用 CT扫描技术和岩心驱替实验， 研究了裂缝性油藏调堵液流转向机理， 通过 CT图像呈现岩心孔隙特征、 油水分布及裂缝封堵后注入水扩大波及体积过程。结果表明， 人工裂缝贯穿整条岩心， 孔隙分布均匀， 平均孔隙度 22.7%， 注入水沿着裂缝窜流， 不能建立起有效的驱替压差， 基质波及程度低， 一次水驱原油采收率仅为 10.6%。改性淀粉凝胶可有效封堵裂缝孔道， 迫使注入水液流转向， 启动岩心基质， 二次水驱波及体积大约扩大到岩心基质体积的 2/3， 最终采收率为 46.1%， 提高了 35.5%。CT扫描技术为研究封堵裂缝性油藏机理提供了可视手段。图 7参 18

When researching plugging and fluid diversion in fractured reservoir by conventional method，pore structures and fluid flow characteristics could not be observe. the artificial fracture was plugged by modified starch gel and the plugging and fluid iversion in fractured reservoir was investigated on basis of computed tomography（CT）scanning technology and laboratory experiment. CT images presented the characteristic of core pores，oil and water distribution，and the process of improving swept volume after fracture was plugged. Experiment results showed that the artificial fracture run through the whole core，with uniform pore distribution and an average porosity of 22.7%. Serious water channeling in artificial fractures resulted in the displacing pressure could not be built up effectively and swept volume in matrix was low. The oil recovery of water flooding was only 10.6%. When the fracture was plugged by the modified starch gel system，the subsequent water was compelled to fluid diversion and started core matrix. Swept volume of subsequent water was more than 2/3 of matrix volume approximately，the total oil recovery was of 46.1%，enhanced by 35.5%. CT scanning technology provided a visual method for mechanism study of plugging fractured reservoir.

10.19346/j.cnki.1000-4092.2016.04.012