新型储层改造用暂堵转向剂研究及应用

Research and application of a new type of temporary plugging diverting agent for reservoir reconstruction

针对现有暂堵转向剂突破压力低、耐温性差,部分暂堵转向剂存在纤维缠绕分散不均或因表面快速水化而聚结"成团"等问题,采用直链型聚合物细颗粒与粒径更小的水膨体复配,引入矿物油对其进行分散,使其表面具有一定疏水性,从而制备出了一种新型储层改造用暂堵转向剂。该暂堵转向剂利用不同粒径材料的堆砌、架桥作用,在基质和裂缝的端面以及裂缝内部形成堵剂层,并利用水膨体的吸水膨胀作用进一步填充颗粒间的空隙,提高了封堵率。室内实验表明,该暂堵转向剂耐140℃高温,可直接加入水基储层改造液体中注入地层,在储层温度下逐渐溶解/降解,对基质和裂缝均具有良好的封堵效果,封堵率>99%,封堵后的正向突破压力≥60 MPa。该暂堵转向剂在四川页岩气储层体积压裂中开展了8段次的现场试验,均取得了良好的转向效果。

Aiming at the problems of low breakthrough pressure,low temperature resistance of temporary plugging diverting agent,and scattering unevenly due to fiber winding or togethered'cloud'due to surface rapid hydration,the linear polymer fine particles with particle size smaller water-swelling polymer were matched,and it was dispersed with mineral oil to make it have certain hydrophobic surface,then a new type of temporary plugging diverting agent for reservoir reconstruction was prepared.The temporary plugging diverting agent take the stack and bridging action of different particle size material to form plugging agent layer in the matrix and cracks face and in the cracks internal,use the water absorption expansion effect of water-swelling polymer to filled the pore between particles furtherly,and improve the plugging rate.Laboratory experiments results show that the temporary plugging diverting agent can be resistant to 140 ℃,and can be directly injected to form with water-based reservoir reconstruction liquid together.The temporary plugging diverting agent will gradually dissolve/degrade under the reservoir temperature,and has good plugging effect for matrix and cracks,plugging rate>99%,positive breakthrough pressure after plugging ≥60 MPa.The temporary plugging diverting agent has carried out 8period of time of field tests,and has achieved good diverting effect in Sichuan shale gas reservoir volume fracturing.