新型自愈合水泥研制

Development of New Self-Healing Cement

为解决固井结束后出现微环隙或者微裂缝造成环空窜流的问题,研究出一种新型自愈合水泥。该水泥浆以阴离子型聚异戊二烯胶乳(IR)作自愈合组分,胶乳粒度较大,粒径主要分布在1.44μm左右,但分布范围较窄。通过室内实验,优选出了可在常温IR胶乳水泥浆中使用的稳定剂AES、FW-1,可在高温IR胶乳水泥浆中使用的稳定剂FW-2,该水泥浆的常规浆体性能满足固井要求。初期性能评价结果表明,室温下IR胶片2 h内的吸煤油量达11.2 g/g,吸液化石油气的量为3.5 g/g,可以满足膨胀密封微裂缝作用;而且溶胀后的胶乳是黏稠而稍具流动性的体系,在压力作用下会有一定程度的运移,大量溶胀胶乳在微裂缝或微环隙某部位积聚而使其闭合,切断油气窜流通道,表明IR胶乳水泥具有实现自愈合的可行性。

A new self-healing cement slurry was developed to solve the annular channeling problem existed in the micro annular spaces and fractures in cement sheath. This slurry contains anionic polyisoprene(IR) latex as self-healing additive. The IR latex has bigger particles of about 1.44 μm, with a narrow particle size distribution. Different stabilizers were selected for use in the IR latex cement slurries, AES and FW-1 in normal temperature, and FW-2 in high temperature. At normal temperatures, the IR latex adsorbs 11.2 g/g kerosene and 3.5 g/g LPG in 2 hours, respectively, satisfying the needs for sealing micro fractures. The IR latex becomes thickened and has slight fluidity when swore in cement slurry, and may move to some distance under pressure. These swelling IR latex accumulates and plugs the micro fractures and micro annular spaces in cement sheath, cutting off the channeling path of oil and gas, indicating that the IR latex is of self-healing.