Optimization Design Method for Key Acid Parameters in Carbonate Reservoir Stimulation in the Gaoshiti-Moxi Area

Abstract The Dengying Formation gas reservoir in the Gaoshiti-Moxi area is abundant in resources, and gelled acid fracturing technology is currently the primary method used for efficient development. However, under clarified geological and engineering conditions, the current acid formulation design lacks precise decision-making support. This has resulted in inadequate compatibility between the acid system, the reservoir, and operational processes, thereby limiting the stimulation effect. To address this issue, a proxy model for acid-fracture propagation based on the reservoir stimulation coefficient was developed. By integrating the proxy model with orthogonal experimental design, the influence of various acid parameters on acid fracturing stimulation was systematically analyzed. Consequently, an optimized acid parameter chart was created for different reservoir types. As a case study, the optimized acid parameter design was applied to Well X3 in the Moxi area. The results revealed that the actual acid parameters used during the operation closely aligned with the recommended scheme, achieving a post-fracturing test production of 55.96 × 10 4 m 3 /d, thereby demonstrating a significant production enhancement. These findings provide valuable guidance for acid design in carbonate acid-fracturing wells within the same block, contributing to improved reservoir stimulation outcomes.