交变载荷下固井水泥环完整性研究

目前，我国页岩气的开发方式多采用水平井套管完井和大排量分段压裂工艺技术。通过分段压裂工艺，使水力主裂缝沟通储层天然裂缝及岩石层理，从而形成裂缝网络，实现储层有效改造。由此，大型压裂时水泥环密封完整性问题日渐突出。本文采用G级油井水泥和页岩气固井水泥，分别探究其在不同温度压力及循环载荷条件下的水泥环完整性，进而为交变载荷下固井水泥环的力学完整性提供技术支撑。

Study on integrity of cement sheath under alternating loads

At present, the development of shale gas in China mainly adopts horizontal well casing completion and large displacement segmented fracturing process technology. Through the segmented fracturing process technology, the hydraulic main fracture communicates the natural fractures of the reservoir and the rock stratigraphy, thereby forming a complex fracture network and realizing the effective transformation of the reservoir. At the same time, the problem of integrity of cement sheath sealing in large fracturing is gradually becoming prominent. In this paper, G-class oil well cement and shale gas well cement are used to explore the integrity of cement sheath under different temperature pressures and circulating load conditions respectively, providing technical support for the mechanical integrity of cement sheath under alternating loads.