Numerical Simulation of Two-Phase Fluid-Structure Interaction in Fractured Formation Under Drilling Conditions

Abstract

In the course of drilling fractured formation, influenced by drilling parameters and different working conditions, the stress distribution around the well changes, resulting in fracture opening or closing, easy to cause leakage or overflow and other well control accidents. In this study, COMSOL Multiphysics software is used to simulate the stress variation, fracture deformation and gas-liquid two-phase saturation distribution around a well under different drilling conditions and fracture patterns. It is found that the fractures will open in different degrees when drilling vertical and parallel to the wellbore, and the crack opening and permeability will increase gradually with time, the distribution of near-well zone fluid saturation becomes wider, which shows that the drilling fluid gradually invades the fracture with the opening of the fracture and bursts into the depth of the formation Under the action of exciting pressure, fracture width and permeability are larger than those under normal drilling, The two-phase fluid-solid coupling law of fractured formation obtained in this study provides a reference for field well control program.