TY - JOUR
TI - Discrete element analysis on the influence of drilling fluid pressure on core discing in pressure-preserved coring
AU - Wang Ding-Ming
AU - Chen Ling
AU - Guo Da
AU - Liu Zhi-Qiang
AU - Li Ju
AU - Yang Xun
AU - Zhang Yi-Wei
JN - Thermal Science
PY - 2023
VL - 27
IS - 1
SP - 655
EP - 665
PT - Article
AB - In the process of coring in a high in-situ stress environment, the rock core  is damaged due to stress release, and core discing is a prominent  manifestation of this damage. Pressure-preserved coring has no direct effect  on in-situ stress, and its influence on stress release is related to  drilling fluid pressure. Yet fluid pressure in the coring process was not  considered in most former numerical simulation studies on core discing. In  this paper, the discrete element method software PFC3D is used to conduct a  numerical simulation of the coring process. According to the two conditions  without drilling fluid pressure and with it, and different horizontal  in-situ stresses of 5-160 MPa, fracture and discing of the core with  drilling are observed. In addition, the law of fracture and discing in the  process of coring was studied, and the function of pressure-preserved coring  to prevent fracture and discing is explored. Simulation results show  nonlinear trends in distribution of discs both in time and in space.