储气库井弹性自愈合水泥浆体系及其性能评价

由于储气库存在季节性调峰需求，其工作时井筒水泥石会受到交变载荷作用，导致密封完整性易被破坏。针对这一问题，优选了自愈合评价方法，研究选择了一种结晶型自愈合剂（JHR-1），分析了其自修复原理并以其为主体，在优选复配纤维JX46-12、丁苯胶乳PLT-100及其他外加剂的基础上，形成了密度1.89 g/cm3的弹性自愈合水泥浆体系，并对其性能进行了评价。结果表明，在养护14 d后其裂缝最大愈合宽度超过150 μm，28 d后超过250 μm；7 d压折比与抗冲击韧性分别为4.52、3.87 J/cm2，韧性较好，7 d胶结强度达到6.76 MPa；弹性模量仅5 018 MPa，弹性极限应力与应变分别为39 MPa、0.67%，弹性表现好；循环应力加载第5周弹性恢复率达50%以上，弹性恢复性能好，水泥石疲劳强度高。在储气库井口压力为13~39 MPa条件下可保持水泥石完整性，在载荷超过了水泥石弹性极限应力产生了微裂缝情况下也能快速修复裂缝。

Elastic self-healing slurry system used for gas storage wells and its property evaluation

One role of gas storage is seasonal peak shaving. And during its operation, the set cement in the wellbore undergoes the alternating loads, and its sealing integrity tends to be damaged easily. To solve this problem, the self-healing evaluation method was selected. Then, a kind of crystalline self-healing agent (JHR-1) was researched and selected, and its self-repairing principle was analyzed. After combination fiber (JX46-12), styrene butadiene latex (PLT-100) and other additives were optimized, the elastic self-healing slurry system with the density of 1.89 g/cm3 was developed with the crystalline self-healing agent (JHR-1) as the main part. Finally, its properties were evaluated. It is indicated that its maximum crack healing width is over 150 μm after 14 days' maintenance and over 250 μm after 28 days' maintenance. The ratio of compressive strength to flexural strength and the anti-impact toughness after 7 days' maintenance are 4.52 and 3.87 J/cm2, respectively, indicating better toughness. The cementing strength after 7 days' maintenance is 6.76 MPa. The elastic modulus is only 5 018 MPa, and the elastic limit stress and strain are 39 MPa and 0.67%, respectively, indicating good elasticity. After cyclic stress is loaded by 5 weeks, the elastic recovery rate is over 50%, which indicates that its elastic recovery capacity is good and the fatigue strength of set cement is high. When the wellhead pressure of gas storage well is in the range of 13-39 MPa, the set cement can be remained integral. And if micro-cracks are generated when the load is higher than the elastic limit stress of set cement, they can be healed quickly.