Transient pressure analysis of a horizontal well with multiple, arbitrarily shaped horizontal fractures

Abstract

Hydraulic fracturing is an important process to increase the productivity of wells. In shallow reservoirs, tectonically active reservoirs, and abnormally high-pressure reservoirs, fractures caused by hydraulic stimulation are likely to be in the horizontal direction. To date, the study of transient pressure behavior arising from horizontal fractures has been limited to that of a single horizontal fracture, without consideration of the interference from multiple fractures. In this work, we develop an analytical method to model, and analyze the transient pressure behaviors from multiple horizontal fractures.The results show that the flow regimes of multiple horizontal fractures can be divided into linear flow, transition flow, first pseudo radial flow, bi-radial flow, and second pseudo radial flow. Compared to the case of a single horizontal fracture, the first pseudo radial flow and bi-radial flow represent new flow regimes inherent in the multiple horizontal fracture system. Sensitivity analysis indicates that changes in horizontal fracture length affect the linear flow, transition flow, and first pseudo radial flow. In addition, the first pseudo radial flow and bi-radial flow are closely related to the fracture spacing and fracture number. The transition flow is dominated by the fracture's vertical position and formation thickness.