Analysis of Fracture Initiation Pressure of Tight Sandstone in HangJinQi

Abstract

Simply increasing the fracture length to enhance the conductivity of the reservoir has limited success in increasing the production rate, thus hampering the pace of production at Hangjinqi. To combat this problem, a mathematical model was developed to determine the onset pressure of tight sandstone in Hangjinqi based on the Mohr-Coulomb criterion. It is shown that the onset angle decreases with increasing trap inclination, thus making it difficult to close the fracture with high horizontal pressure and suction. As for the block, it is one of Sinopec’s major areas for developing tight, low-permeability oil and gas in the Ordos Basin. To address this issue, a mathematical model was developed for the onset pressure of tight sandstone in Hangjinqi, taking into account factors such as vertical principal stress, maximum horizontal principal stress, minimum horizontal principal stress, and fracture inclination.The case of trap HE1 in JPH-416 was solved using a minimal bisection method, showing that the onset angle increases with trap inclination. As the fracture inclination increases, the fracture closure pressure gradually increases, and the effect of the minimum horizontal and vertical principal stresses becomes more pronounced.