新型水溶性暂堵剂在重复压裂中的暂堵转向效果

重复压裂是恢复油井产能、提高最终采收率的重要方式之一，目前最有效的重复压裂方式是暂堵剂的转向压裂改造。采用可生物降解材料、高分子量聚合物、膨胀剂和固化剂合成了一种环保型水溶性暂堵转向剂，该暂堵剂颗粒尺寸可根据裂缝宽度定制，水溶性良好，压裂施工结束后4 h可水溶降解；岩心实验表明，该水溶性暂堵剂岩心封堵效率可达99%以上，承压40 MPa以上，且水溶降解后对岩心的伤害较小，满足重复压裂施工各项指标的要求。现场试验1口井，施工过程中加入暂堵剂后施工压力上升3 MPa，起到了良好的暂堵效果，压后增油量为1.1 t/d，含水率下降5%，说明该压裂模式能够起到恢复油井产能、降低含水的目的。 

A New Water Soluble Temporary Plugging Agent and its Temporary Plugging and Diverting Effects in Re-fracturing

Re-fracturing of an oil well is one of the important methods of restoring its production capacity and enhancing its ultimate recovery. The most effective re-fracturing method presently in use is to fracture the reservoir formations with fracturing fluid containing temporary plugging agent functioned as diverting agent. An environmentally friendly water soluble temporary plugging diverting agent has recently been developed with biodegradable materials, high molecular weight polymers, an expansion agent and a solidifying agent. The particle sizes of this temporary plugging agent can be customized to fit for the width of fractures into which the particles will go in. The temporary plugging agent dissolved 4 hours after the fracturing operations. Laboratory experiments on cores indicated that 99% of the pores in the cores can be plugged by this plugging agent, with pressure bearing capacity of at least 40 MPa. The dissolved plugging agent had only minor impairment to the permeability of cores, meaning that the temporary plugging agent had satisfied the needs of fracturing job. On field trial on a well, after adding the temporary plugging agent, operating pressure went up to 3 MPa, proving that the temporary plugging agent functioned very well. Daily oil production rate of the fractured well was increased by 1.1 t, and water cut of the well was reduced by 5%, indicating that the use of this fracturing method has realized the goal of restoring production capacity and reducing water cut.