高温成胶可降解聚合物凝胶堵漏剂的研制与评价

Development and Evaluation of a High Temperature Gelling and Degradable Polymer Lost Circulation Material

以甲基丙烯酸酐对明胶进行季铵化改性,合成了一种可聚合改性明胶交联剂。基于热熔胶的热塑性,成功将引发剂包覆在热熔胶颗粒中,实现高温缓释引发。利用丙烯酰胺(AM)和自制交联剂(DGCL)为原料研发了抗高温可降解聚合物凝胶堵漏剂P(AM-DGCL)。利用核磁共振对自制交联剂进行了结构表征,并对凝胶的力学行为、封堵能力和破胶性能进行了测试。结果表明,P(AM-DGCL)凝胶堵漏剂成胶时间随热熔胶引发剂胶囊浓度的增大而缩短,随温度的增加,成胶时间逐渐减少,150℃高温下成胶时间在2~13h可调;P(AM-DGCL)表现出优良的力学性能,断裂延伸率达1279%,拉伸强度为0.0425MPa;由于起化学交联作用的交联剂DGCL本身具有可破胶性,在高温和破胶剂的作用下P(AM-DGCL)凝胶16h破胶率达95%以上,保证了储层漏失封堵后的反排能力。

A polymerized modified gelatin crosslinking agent DGCL is developed through quaternization of gelatin with methacrylic anhydride. An initiator is successfully wrapped in ethylene vinyl acetate (EVA) particles based on the thermoplasticity of EVA to realize slow release of initiator at elevated temperatures. A high temperature degradable polymer gelling lost circulation material (LCM) P(AM-DGCL) was developed using acrylamide and a self-made crosslinking agent DGCL. The initiator DGCL was characterized with NMR and the mechanical behavior, plugging capacity and gel-breaking property of the gelling LCM tested. It was found that the gelation time of P(AM-DGCL) decreases with increase in the concentration of the initiator capsules and increase in temperature. The gelation time can be controlled within 2 – 13 h at temperature of 150 ℃. P(AM-DGCL) has excellent mechanical property;the percent elongation at break is 1,279% and the tensile strength is 0.0425 MPa. Since the crosslinking agent DGCL itself has gel-breaking property, the 16 h percent gel-breaking of P(AM-DGCL) is at least 95% at the action of high temperature and gel breaker, ensuring the flowback of a plugged reservoir because of lost circulation.