弹性膨胀自密封水泥浆技术研究与应用

The Studyof the Technology of Expansion Elastic Self-Sealing Cement Slurry and Its Application

涪陵焦石页岩气田是我国第一个投入商业化开发的国家级页岩气示范区。涪陵页岩气井地质构造特殊，普遍采用大型体积压裂技术完井，水泥环的完整性极易在压裂施工中受到破坏。井口带压问题不仅影响着后期的施工作业，也增大了完井风险。因此，提高水泥环的整体密封性，防止环空气窜是改善页岩气井井口带压问题的关键。笔者通过对水泥环密封失效的原因分析，提出了膨胀弹性自密封水泥浆体系的设计原理和思路，通过实验评价和现场应用发现，膨胀弹性自密封水泥浆在气井中具有明显的封固和密封作用。

Fuling liaoshi Shale Gas Field was the first national shale gas demonstration area for commercial development. The geological structure of Fuling Shale Gas was special, where large volume frac- turing completion technology was widely used; the integrity of the cement sheath was easy to be damaged in fracturing. The wellhead pressure problem not only affected the operation at the late stage, but also increased the risk of completion. Therefore, the key for improving the sealing per- formance of the whole cement sheath and preventing gas channeling was the key to solve the problem of the shale wellhead pressure. By analyzing the reasons of cement sheath sealing failure, the design principle and method of elastic expansion self sealing cement slurry system are put forward, the experimental evaluation and field application show that the expansion and elastic self sealing cement slurry was obvious effect of sealing in the gas wells.