Experimental study on the long-term stability of shale rock wellbore under high hydraulic pressure

被引：0
作者：
Zhao B. [1 ,2 ,3 ]
Wang X. [1 ,4 ]
Huang W. [1 ,2 ]
Huang T. [1 ,2 ]
Liu Y. [1 ,2 ]
机构：
[1] School of Civil Engineering and Architecture, Chongqing University of Science and Technology, Chongqing
[2] Chongqing Key Laboratory of Energy Engineering Mechanics & Disaster Prevention and Mitigation, Chongqing
[3] The Key Laboratory of Well Stability and Fluid & Rock Mechanics in Oil and Gas Reservoir Of Shaanxi Province, Xi’an Shiyou University, Xi’an
[4] Chongqing College of Architecture and Technology, Chongqing
来源：
Arabian Journal of Geosciences | 2021年 / 14卷 / 3期
基金：
中国国家自然科学基金;
关键词：
Creep; Hydraulic pressure; Rock mechanics; Shale rock; Wellbore stability;
D O I：
10.1007/s12517-021-06484-x
中图分类号：
学科分类号：
摘要：
Hydraulic pressure is one of the important factors influencing the stability of well rock. In this paper, the sleeve typed shale rock specimens were used to laboratory simulate the long-term stability of shale rock wellbore under hydro-mechanical coupled condition. Based on the analysis of triaxial tests data, the strength characteristic of the saturated shale specimens was first studied. The results show that the strength presents an exponential decreasing trend with increasing hydraulic pressure; 5 MPa hydraulic pressure resulted in the axial compressive strength declined by around 12.20% and about 17.78% fell under the hydraulic pressure of 10 MPa. The creep behavior of the shale was also analyzed in detail. It was found that 60% of the triaxial compression strength can easily lead to rupture of specimen under hydraulic pressure of 5 MPa, while more than 73% of the triaxial compression strength is needed under the same confining pressure without hydraulic pressure. The hydraulic pressure as well as its action time obviously affects the wellbore failure characteristics, which may lead to the damage area appearing pulverized, seriously reducing its mechanical properties. A new viscoelastic-plastic creep damage model was proposed to describe the creep behavior of shale rock, and it was found that the creep model can be used to predict the long-term stability of the wellbore. © 2021, Saudi Society for Geosciences.
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