摘要：Wellbore instability is a widespread problem when drilling in shale formations, particularly with water based drilling fluid. The main reason for the occurrence of wellbore instability is that stress concentration and pore pressure redistribution occur around the wellbore once a hole is drilled; current studies show that the drilling fluid temperature and solute mass fraction play important roles during the process. In this work, a non-linear fully coupled chemo-thermo-poroelastic finite element model is developed to quantitatively access thermal and chemical effects on time-dependent pore pressure and effective stresses; in addition, material constant sensitivity analysis of an inclined well drilled in a transversely isotropic formation is presented. The results reveal the following: fluid transfer is greatly affected by thermal and chemical osmosis, the lower temperature and higher solute mass fraction of the drilling fluid contribute to decreasing the pore pressure and are beneficial for wellbore stability, and thermal parameters (such as thermal osmosis coefficient and thermal diffusivity) and chemical parameters (such as reflection coefficient and solute diffusion coefficient) have high effects on the pore pressure and effective stresses. Anisotropy ratio analysis of the material constants indicates that the pore pressure and effective stresses are very sensitive to Young's modulus and the permeability ratio, but are not sensitive to Poisson's ratio. Therefore, the developed coupled chemo-thermo-poroelastic theory illustrates that optimization of the reduction of the drilling fluid temperature while maintaining a high solute mass fraction could enhance wellbore stability. (C) 2017 Elsevier B.V. All rights reserved.

关键字：Chemo-thermo-poroelastic Fully coupled Finite element Wellbore stability Shale

ISSN号：1875-5100

卷、期、页：卷: 40 页: 24-37

发表日期：2017-04-01

期刊分区（SCI为中科院分区）：三区

收录情况：SCIE（科学引文索引网络版）,ESI（基本科学指标数据库）,EI（工程索引）

发表期刊名称：JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING

参与作者：杨柳

通讯作者：曹文科,李扬,高佳佳

第一作者：邓金根,刘伟,蔚宝华,谭强

论文类型：期刊论文

论文概要：曹文科,邓金根,刘伟,蔚宝华,谭强,杨柳,李扬,高佳佳，Pore pressure and stress distribution analysis around an inclined wellbore in a transversely isotropic formation based on the fully coupled chemo-thermo-poroelastic theory，JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING，2017，卷: 40 页: 24-37

论文题目：Pore pressure and stress distribution analysis around an inclined wellbore in a transversely isotropic formation based on the fully coupled chemo-thermo-poroelastic theory