Numerical simulation study on factors affecting the pre-CO2 fracturing effect in shale oil reservoirs: A case study on Kong-2 member in Cangdong Sag, China

Abstract

A novel procedure has emerged in recent years within oilfields ? namely, the utilization of a hybrid fracturing method employing pre-CO2 injection along with sand-carry slick water. In this paper, based on the real logging data of shale oil reservoirs in the second member of Cangdong Sag, Huanghua Depression, combined with the GOHFER, a coupled 3-D hydraulic fracture propagation model is proposed. This research delves into an examination of how engineering factors exert their influence on the process of fracture propagation. The quantitative analysis is conducted encompassing critical fracture parameters such as half-length, height, and width, and self-defined fracture seepage area and fracture front fractal dimension. The research findings indicate that as injection displacement increases, the fracture shape undergoes a transformation from being ?long, low, and wide? to becoming ?short, high, and narrow?.