A boundary element method for pressure transient analysis for irregular 3D fracture

Boundary element methods and mesh reduction techniques enable efficient simulation of complex fracture geometries. In shallow reservoirs and coal bed methane formations, horizontal fractures are prone to develop. However, the irregular morphology of three–dimensional fractures is not considered by the existing horizontal fracture models. This paper presents a new well–test model based on boundary element method for irregular fracture in low-permeability reservoirs. In this study, the pressure transient behaviors of an oil well with complex fracture geometries are studied, using an efficient boundary element model. The boundary element model has the capability to simulate well performance by considering complex non–planar hydraulic fractures. The pressure transient solution of the boundary element model is obtained by means of the finite difference method, spatial source function and Laplace transforms. Moreover, we use a convolutional method for the wellbore–fracture connection, which makes the description of the pressure transient behavior at the early stage more accurate. After the numerical verification of the proposed boundary element model, we apply it to analyze the key fracture parameters that influence the pressure transient behaviors, including fracture conductivity, fracture position, reservoir thickness, fracture shape factor, fracture inclination angle, and fracture area.