Zhang Huabin, Li Quanen, Yue Xianru, Ba Jinhong, Ding Shuanglong
School of Mechanical and Engineering, Liaoning Technical University, Fuxin, 123000, China.
PetroChina Research Center of Salt-Cavern UGS Technology, Zhenjiang, 212002, Jiangsu, China.
Sci Rep. 2024 Sep 28;14(1):22529. doi: 10.1038/s41598-024-73067-7.
Under the premise of guaranteeing the stability of the gas storage reservoir, reducing the thickness of the salt layer on the top plate of the gas storage reservoir can improve the utilization rate of the salt layer in the construction section and increase the vertical height of the gas storage reservoir cavity, creating a larger gas storage space. The mechanical planar model of the casing-cement sheath-surrounding rock in the top plate of the salt cavern gas storage reservoir yields the elastic-plastic theoretical solution for the stress and deformation of the well wall surrounding rock. Based on this, a three-dimensional mechanical numerical model of the top plate is constructed to compare the effects of various top plate thicknesses on the surrounding rocks of the gas storage reservoir and to analyze the stress and deformation behavior of the wall surrounding the rock of the top plate of the reservoir in the cementing section and bare wells under the long-term injection and extraction cycle. The results indicate that reducing the thickness of the roof salt layer primarily affects vertical displacement, radial displacement, equivalent strain, and principal stress changes in the cement sheath and surrounding rock. All other roof parameters, except for equivalent strain, show an increasing trend. Reducing the salt layer thickness in the cementing section has the least impact on the gas storage roof's stability. In contrast, reducing the salt layer thickness in the cementing section and bare wells has a moderate impact, while reducing the thickness solely in the bare wells is the most detrimental. These findings provide valuable insights for optimizing the roof thickness of gas storage facilities and enhancing the utilization of the limited salt layer in the reservoir section.
在保证储气库稳定性的前提下，减小储气库顶板盐层厚度，可提高建设段盐层利用率，增加储气库腔体垂直高度，创造更大储气空间。盐穴储气库顶板套管 - 水泥环 - 围岩的力学平面模型得出了井壁围岩应力与变形的弹塑性理论解。在此基础上，构建顶板三维力学数值模型，比较不同顶板厚度对储气库围岩的影响，分析长期注采循环下固井段和裸眼井储气库顶板围岩的应力与变形行为。结果表明，减小顶板盐层厚度主要影响水泥环和围岩的垂直位移、径向位移、等效应变和主应力变化。除等效应变外，其他顶板参数均呈上升趋势。减小固井段盐层厚度对储气库顶板稳定性影响最小。相比之下，减小固井段和裸眼井盐层厚度影响适中，而仅减小裸眼井盐层厚度最为不利。这些研究结果为优化储气库设施顶板厚度和提高储层段有限盐层利用率提供了有价值的见解。
