Breakdown Pressure Prediction of Tight Sandstone Horizontal Wells Based on the Mechanism Model and Multiple Linear Regression Model

Abstract

Accurately predicting the breakdown pressure in horizontal sections is essential when designing and optimizing fracturing jobs for horizontal wells in tight gas reservoirs. Taking the Sulige block in the Ordos Basin as an example, for different completion methods combined with indoor rock experience data and well data, a new method for predicting breakdown pressure based on a linear regression model is proposed. Based on the Hossain horizontal well stress field model, this paper established a calculation model of breakdown pressure under different completion methods by using experimental and well data. The average error between the calculation results and the actual breakdown pressure at the initiation point is 3.67%. A Pearson correlation analysis was conducted for eight sensitive factors of horizontal well stress, which showed that the maximum horizontal principal stress, minimum horizontal principal stress, tensile strength, and elastic modulus had strong linear correlations with breakdown pressure. In this study, multiple linear regression was used to establish the prediction model of breakdown pressure under different completion conditions, and the calculation method of the prediction model was optimized. The model was verified using the relevant data for four horizontal wells. The average relative error between the prediction model and the actual breakdown pressure was 4.33–6.30%, indicating that the breakdown pressure obtained by the new prediction model was similar to the actual conditions. Thus, the prediction model is reasonable and reliable.