Borehole Wall Protection and Stability Control Technology for Deep-Hole Drilling in High In-Situ Stress Strata
高地应力地层深孔钻探护壁与稳定控制技术

摘要

随着深层矿产资源的开采以及地下空间的应用越来越广泛，在这样的大背景下，对高应力地层中深孔钻探所遇到 的卡钻失稳的问题也越来越严重化成为了影响整个项目的进展过程中的一个很大的技术难题。文章通过系统的研究分 析了在高应力地层中孔洞失稳的发生原因，即主要是由地应力和工程扰动共同作用下所造成的由于岩石强度低于地应 力的压力而产生的剪切破坏、拉伸破坏以及蠕变变形等现象的结果来得出的结论。同时针对这个现象从优化钻井液配 方，设计合理化的套管方案出发提出了针对性的护壁技术；另外从优化钻孔路径、调整钻进参数、孔壁压力释放、孔 壁加固封堵等方面入手制定了系统的钻孔稳定的控制措施。更进一步的研究的是关于孔壁稳定性的评估标准、现场实 时监测报警手段、围护结构整体评价体系和技术经济效益相适应程度等的技术应用成效评价系统。 

Abstract

With the exploitation of deep mineral resources and the increasingly extensive application of underground space, drilling jamming and instability encountered in deep-hole drilling under high-stress strata have become increasingly serious, posing a major technical challenge to the progress of related projects. This paper systematically analyzes the causes of borehole instability in high-stress strata. The results indicate that borehole instability is mainly caused by the combined effects of in-situ stress and engineering disturbance, leading to shear failure, tensile failure, creep deformation, and other phenomena when rock strength is lower than the pressure exerted by in-situ stress. In response to this problem, targeted borehole wall protection technologies are proposed from the perspectives of optimizing drilling fluid formulations and designing rational casing programs. In addition, systematic borehole stability control measures are developed, including optimization of drilling paths, adjustment of drilling parameters, borehole wall pressure relief, and borehole wall reinforcement and plugging. Furthermore, an evaluation system for the application effects of related technologies is established, covering borehole wall stability assessment criteria, on-site real-time monitoring and early warning methods, overall evaluation of support structures, and the adaptability between technical measures and techno-economic benefits.