摘要
孔壁失稳是目前水平定向钻进工程中经常遇到的一个实际问题,尤其是在地表的第四纪松散地层中钻进孔壁失稳更是屡见不鲜,严重影响工程施工。针对以往研究中没有考虑渗流场对孔壁稳定性的影响问题,本文在Biot固结理论的基础之上,建立了应力场和渗流场耦合数学模型,采用有限元方法对所建立的模型进行求解。通过对某一水平定向钻进孔壁稳定性进行数值模拟,分析了在流固耦合作用下地层孔隙压力、有效应力和位移的变化规律,并分析了在不同的冲洗液压力下,地层沉降情况。研究发现,在定向钻进过程中,流固耦合作用对地层特别是井壁附近围岩的应力和变形影响很大。研究结果为钻进过程中避免孔壁失稳,合理选择冲洗液及冲洗液压力提供理论依据。
Borehole instability is often encountered in horizontal directional drilling projects that is a practical problem, especially in the loose surface of the Quaternary strata, the borehole instability is common, and has serious impact on the construction work. Due to the fact that the influence of the seepage field on the borehole stability prob- lem was not considered in previous studies, this paper on the basis of the Biot consolidation theory, develops a cou- pling mathematical model for the stress field and the seepage field, and using the finite element method to solve the model. In addition, through numerical simulation for the borehole stability of a directional drilling hole, the paper an- alyzes the effect of the fluid-solid coupling on pore pressure, effective stress and displacement of the soil around the borehole, and also analyzes the ground settlement under different fluid pressures. Simulation results show that the flu- id-solid coupling in horizontal directional drilling has great influence on stress field and deformation field of borehole soil. The results can provide a theoretical basis for the drilling process to avoid the instability of the borehole and how to select a reasonable mud and mud pressure.
出处
《地下空间与工程学报》
CSCD
北大核心
2012年第4期796-801,共6页
Chinese Journal of Underground Space and Engineering
关键词
流固耦合
孔壁稳定
有限元
数值模拟
fluid-solid coupling
borehole stability
FEM
numerical simulation
