Exploring the power of machine learning in analyzing the gas minimum miscibility pressure in hydrocarbons

Abstract

Minimum Miscibility Pressure (MMP) plays a crucial role in subsurface gas injection processes. Hence, the accurate determination and analysis of the effective parameters on MMP are vital for a successful injection project. In this study, different Machine Learning (ML) algorithms are used to identify the most influential parameters on the MMP and develop reliable predictive models. A comprehensive database containing 812 samples (almost all the available experimental data set published from 1961 to 2022) is collected from 66 open literature studies. Six algorithms were employed for feature selection: Sequential Forward Selection (SFS), Sequential Backward Selection (SBS), Sequential Forward Floating Selection (SFFS), Sequential Backward Floating Selection (SBFS), Lasso Regression (LR), and Random Forest Feature Importance (RFFI). These feature selection algorithms were evaluated using a Decision Tree (DT) regressor. The most important features from 42 potential features were x C₅, x C₆, x C₂-C₆, MW C₇⁺, MW Gas, TC, and T, selected using the SBFS method based on the Root Mean Squared Error (RMSE). Using the best-selected features, six predictive models were developed, including LR, DT, Random Forest (RF), Extra Trees (ET), Stacking Regressor (SR), and Voting Regressor (VR). The SR predictive model performed the best with RMSE and R2 values of 18.37 bars and 0.96, respectively, for the testing dataset. The outcomes of this research can be employed for any industrial process involving gas injection into hydrocarbon reservoirs to select the most relevant features in designing the experimental and field trials.