ADAPTIVE FINITE ELEMENT-DISCRETE ELEMENT ALGORITHM, SOFTWARE ELFEN AND APPLICATION IN STIMULATED RESERVOIR VOLUME OF SHALE

The adaptive algorithm of finite element (FE)-discrete element (DE) for fluidic-mechanical-fracture coupling analysis was introduced in this study. The novel computational software ELFEN based on this method was introduced and applied in a three-dimensional mechanism analysis of a staged stimulated reservoir volume of shale. The superconvergent patch recovery (SPR) method was used to obtain the superconvergent FE stress solutions, by which the error of conventional FE stress solutions was estimated. The adaptive local remesh for domains of crack tips was expected to be characterized by efficient analysis strategy and application for more accurate stress solutions and reliable crack propagation path. Numerical examples were given to show the effectivity, reliability and practicability of the numerical algorithm and the software for staged stimulated reservoir volume of single-and multi-horizontal wells with fluidic-mechanical-fracture coupling.