Numerical analysis of hydraulic fracturing processes for multi-layered fractured reservoirs

Accurate simulation of Hydraulic fracturing in naturally fractured reservoirs significantly impacts the prediction of the fracturing treatment process. The objective of this study is to numerically analyze the hydraulic fracturing processes in a multi-layered fractured reservoir. Therefore, mechanical mass balance equations for fluids, solids, and their interactions with produced fractures were simultaneously solved in ABAQUS software based on the finite element method. According to the result of this study, by increasing the layers' depth from layer A to Layer C, the fluid leakage rate has been increased due to the more volumes of fluid loss in higher depths. By plotting linear equations, it can be concluded that linear equations can be derived approximately for other layers without modeling all the layers by deriving one linear equation for one layer. Moreover, the maximum opening pressure for fracturing for Layer A-C is 60, 73, and 78 Mpa, respectively. It is concluded that there is higher pressure needed to opening or creating the new fractures in the formation at higher depths. On the other hand, by deriving polynomial equations for each layer, it is concluded that there is an approximate relationship for each layer, which can be expanded for other layers Moreover, by this approach, it is possible to predict the pressure difference behavior through the fracture propagation length without any unnecessary field application. Consequently, the fracture opening profile is approximately 9.5 for the deepest layer as it has the best junction with the fracture tips and the middle points of the wellbore. (C) 2021 The Author(s). Published by Elsevier Ltd.

Automated summary

This study numerically analyzes hydraulic fracturing processes in a multi-layered fractured reservoir, finding that fluid leakage rate increases with depth, linear equations can be derived for each layer, and the maximum opening pressure for fracturing increases with depth.