抗高温纤维强化凝胶颗粒堵漏剂

井漏是钻井过程中常见的复杂难题，针对常用聚合物凝胶堵漏剂抗温性能差、承压封堵能力弱的问题，通过分子结构设计，以丙烯酰胺、甲基丙烯酸丁酯和2-丙烯酰氨基-2-甲基丙磺酸为单体，柔性纤维为强化材料，过硫酸铵为引发剂，通过与自制大分子交联剂BWL聚合反应，制备了一种新型抗高温纤维强化凝胶堵漏剂。研究了柔性纤维对凝胶堵漏剂流变性能的影响，通过扫描电镜、热重、承压堵漏实验等对凝胶堵漏剂的微观结构、热稳定性、吸水膨胀性和承压堵漏性能进行了研究。结果表明：柔性纤维增强了凝胶堵漏剂的空间网架结构，使其韧性更强；凝胶堵漏剂颗粒具有良好的热稳定性和吸水膨胀性，通过“吸水膨胀、挤压充填”的堵漏原理对漏失通道进行封堵，在140℃下对高渗透性漏失层的封堵承压高于7 MPa，对宽裂缝漏失通道封堵后承压高于5 MPa，可满足高温高压漏失地层中堵漏目的。

A High Temperature Resistant Gel Reinforced with Fiber Used for Lost Circulation

Mud loss is a complex problem frequently encountered in drilling operation. Polymer gel is often used as a lost circulation material (LCM) to control mud losses. Conventional polymer gel lost circulation material has poor high-temperature stability and low-pressure bearing capacity, which are not benefit to mud loss control. A new high-temperature fiber reinforced gel LCM has been developed through molecular structure design using monomers such as acrylamide, butyl methacrylate and 2-acrylamido-2-methylpropanesulfonic acid. A flexible fiber was used as reinforcing material and ammonium persulfate as initiator in the synthesis reaction. The intermediate product was then reacted with a high molecular weight crosslinking agent BWL to produce the final product. The effect of the flexible fiber on the rheology of the gel LCM was studied. The gel LCM was studied, with SEM, thermogravimetric analysis and mud pressured loss control test etc. for its micro structure, thermal stability, swelling performance after water absorption and performance in controlling mud losses under pressure. It was found that the existence of the flexible fiber strengthens the spatial network structure of the gel LCM, making it much tougher. The particles of the gel LCM have good thermal stability and swelling property when absorbing water. When water is absorbed, the gel LCM swells and is squeezed into the channels through which mud is lost to stop mud losses. High permeability loss zones sealed with this gel LCM at 140℃ has pressure bearing capacity of greater than 7 MPa, wide fractured zones sealed with this gel LCM had pressure bearing capacity of greater than 5 MPa, indicating that this gel LCM can be used to control mud losses in high temperature high pressure environment.