OPTIMIZATION OF HYDRAULIC FRACTURING DESIGN AND UNCERTAINTY ANALYSIS IN UNCONVENTIONAL RESERVOIR SHALE GAS

Abstract

This study focuses on the optimization of hydraulic fracturing design and uncertainty analysis in unconventional shale gas reservoirs. The research aims to identify key fracturing parameters that significantly impact recovery, Identify the most effective hydraulic fracturing configuration, and quantify the influence reservoir uncertainties on gas production. A numerical simulation model incorporating shale gas adsorption-desorption mechanisms is used to evaluate critical parameters in fracturing such as the amount number of stages, fracture half-length, stimulated width, height, effective width near the fracture zone, and permeability variations in the fracture and matrix. The optimization process, conducted using tNavigator simulation software, applies sensitivity analysis. Additionally, uncertainty analysis was performed on key reservoir parameters, including Langmuir pressure and volume, matrix and fracture porosity, and permeability variations. The results indicate that the number of stages is the most influential factor, with an optimal stage count of 18 stages. The optimized fracturing design achieves a recovery factor of 22.91%. The analysis uncertainty reveals that Langmuir parameters have the strongest impact on OGIP predictions, emphasizing the role of gas desorption in shale reservoirs. The probabilistic outcome P10; P50; P90 of different reservoir characteristic range highlights the optimized fracturing design, with recovery factors ranging from 13.09%, 18.48%, and 24.07%, confirming its resilience to reservoir uncertainties. Moreover, the study supports economic viability by demonstrating that gas production remains above the economic threshold of 60-100 Mscf/day for unconventional reservoirs.