Method for predicting the injection pressure for horizontal wells in fractured tight sandstone reservoirs

Abstract

Hydraulic fracturing and horizontal well drilling are the key technologies for increasing the production of continental tight sandstone reservoirs. Taking the typical fractured tight sandstone in the Yuan-287 block of the Ordos Basin as an example, a reservoir geological model was established based on the stratigraphic correlation of 206 wells. The model and 3D paleostress field were combined to predict fracture parameters such as density and strike. By using reservoir breakdown pressure (RBP) monitoring data combined with reservoir physical and mechanical parameters, tectonic fracture characteristics, and in situ stress parameters, a quantitative evaluation model of RBP, which predicts the 3D distribution of RBP, was established via the stepwise regression method, and the factors controlling the RBP were analyzed. The rock P-wave velocity, horizontal minimum principal stress and fracture density were found to be three key parameters that control the breakdown pressure of this tight sandstone reservoir. By comparing the fracture opening pressure (FOP) of subsurface tectonic fractures with the RBP, a new method for predicting the optimal water injection pressure (OWIP) of this reservoir was proposed. This work provides a valuable evaluation model for accelerating the efficient development of continental tight sandstone reservoirs.