Investigating the effect of artificial fractures on shale oil production under fluid-solid coupling in hydraulic fracturing

ABSTRACT: Shale oil is a strategically important global resource, and its commercial extraction requires fracking to increase production. However, the impact of different fracture distributions on shale oil production is unclear. The application of hydraulic fracturing technology to horizontal wells has been demonstrated to alter the seepage mechanism within the reservoir, thereby improving the overall development efficiency. To this end, a production prediction model for multi-cluster fracturing of horizontal wells was constructed in this study using the finite element method. Through the variation of the number and distribution of hydraulic fractures, it was determined that augmenting the number of fracture clusters and reducing fracture spacing could substantially enhance shale oil production. Additionally, a comprehensive analysis of the production data was conducted to ascertain the fracture distribution patterns in the transverse direction (uniformly laid, dense at both ends, and dense in the middle) and the longitudinal direction (uniformly laid, spindle-type, and dumbbell-type). The findings indicate that in the transverse direction, dense fractures at both ends have the most significant impact on enhancing yield, followed by uniformly laid fractures, and dense fractures in the middle have a weaker impact; and in the longitudinal direction, the dumbbell type has the greatest impact on improving yield, followed by uniformly laid fractures, and the spindle type has a weaker impact. The comprehensive analyses indicate that the fracture combination of dense and dumbbell type at both ends can significantly enhance the production of shale oil in fracture modification operations, thereby providing a robust theoretical foundation for the optimization of fracture network in shale reservoirs.