固井用防水窜自愈合剂的探索

针对固井后环空窜流遇水问题，笔者开发了防水窜自愈合剂。该防水窜自愈合剂为核壳结构，以高吸水树脂作为核心材料，吸水倍数从尺寸为100 μm开始呈指数增长，30 s内140目的样品吸水量达1898倍，120 s后达到稳定值，约2200倍；120目时吸水量在30 s也可达到892倍左右，120 s达到稳定值约1950倍。通过外部包裹后，其在水中可达到90℃下3 h不吸水的能力。在水泥水化后外壳破坏，其具有吸水自愈合能力。岩心实验表明，90℃下压差为2 MPa条件下防水窜自愈合剂40 min左右可完成裂缝封堵。含4%防水窜自愈合剂的常规密度水泥浆具有良好的流变性能，失水量可控，稠化时间线性正常，抗压强度较高，能够满足浅井固井水泥浆的需求。

Explore and Study on Well Cementing Anti-Water-Channeling Self-Healing Agent

An anti-water-channeling self-healing agent has been developed to deal with channeling in annular spaces after well cementing. This anti-water-channeling self-healing agent has a core-shell structure, it uses highly water absorbent resin as the core material and the size of the core (a sample passing 140 mesh screen) increases exponentially from original 100 μm to 1898 times of the original size in 30 s after absorbing water, and stabilizes at 2200 times of the original size in 120 s. Another 120-mesh sample absorbs water of 892 times of its original size in 30 s and stabilizes at 1950 times of the original size in 120 s. The core, after wrapped on its surface, does not absorb water for 3 h at 90℃. The anti-water-channeling self-healing agent can effectively plug fractures. When the cement is hydrated, the shell is broken and the anti-water-channeling self-healing agent then acquires water absorbency and self-healing ability. Core experiment showed that the anti-water-channeling self-healing agent can plug fractures in 40 min at 90℃and 2 MPa. Cement slurry test showed that normal density cement slurries containing 4% anti-water-channeling self-healing agent have good rheological property and controllable filtration rate, the thickening time of the cement slurries is linear and normal, and the set cement has high compressive strength, satisfying the needs of shallow well cementing.