JY页岩气田水平井预防环空带压固井技术

随着页岩气大规模开发，针对提高页岩气水平井固井质量的研究逐渐增多，但同期页岩气井环空带压情况并未缓解，对页岩气田的安全生产提出了严峻挑战。为解决页岩气井环空带压难题，建立了水泥环密封完整性评价装置，针对JY页岩气田开展了水泥环密封完整性影响因素分析，并相应形成了预防环空带压固井技术。研究认为水泥石胶结差和体积收缩导致早期环空带压，而分段压裂及生产参数变化对水泥石胶结和本体的破坏是页岩气井环空带压的最主要原因。预防环空带压固井技术在JY页岩气田进行了推广应用，压裂投产后带压井比例下降了82%，有效解决了页岩气井环空带压难题，提高了页岩气井水泥环长期密封完整性，保障了页岩气田安全开发。

A cementing technology for preventing the annulus pressure of horizontal wells in JY shale gasfield

With the large-scale development of shale gas, there are more and more researches on how to improve the cementing quality of shale-gas horizontal wells. However, the sustained casing pressure of shale gas wells is not alleviated and brings severe challenges to the safe operation of shale gas fields. To solve this problem, a device for evaluating the seal integrity of cement sheath was built up. Then, the factors influencing the seal integrity of cement sheath in JY Shale Gas Field were analyzed. Finally, the cementing technology for preventing sustained casing pressure was developed correspondingly. It is indicated that poor cementation and volume shrinkage of set cement lead to early sustained casing pressure, and the damage to set cement and its cementation by staged fracturing and production parameter change is the most important reason for the sustained casing pressure of shale gas well. The cementing technology for preventing sustained casing pressure is applied and popularized in JY shale gasField. After fracturing and commissioning, the percentage of the wells with sustained casing pressure declines by 82%. This technology solves the sustained casing pressure of shale gas wells effectively, improves long-term seal integrity of cement sheath in shale gas wells.