Volume 65

Study of Wellbore Stability with Mechanical and Chemical Coupling Based on Digital Core Technology Guangxu Zhou, Chuanliang Yan, Yuanfang Cheng, Zhongying Han, Yan Ye

Abstract

Wellbore stability analysis is an important part of efficient drilling. Because of the difficulty of core extraction in deep stratum, it is difficult for the core to meet the experimental requirements of traditional wellbore stability analysis. Therefore, a new method for analyzing wellbore stability by using cuttings is urgently needed. In this paper, a new method based on digital core technology for the analysis of wellbore stability with mechanical and chemical coupling is proposed. Using this method, the digital core is reconstructed by scanning the cutting sample. Combined with the influence of drilling fluid, a wellbore stability analysis model is established. The elastic mechanical parameters, stress distribution around the well and equivalent plastic strain are analyzed. The results show that the influence of drilling fluid can be introduced into the digital core, and the stress distribution around the well and equivalent plastic strain obtained based on the digital core are similar to the results of the triaxial compression experiment. It is feasible to introduce the influence of drilling fluid into a digital core to realize mechanical and chemical coupling wellbore stability analysis based on a digital core, which is a new direction of wellbore stability analysis in complex formations.

Keywords rock mechanics, digital core, wellbore stability, drilling fluid