Abstract The marine shale gas reservoirs in the southern Sichuan Basin exhibit strong lateral heterogeneity and complex natural fracture development. Multi-cluster fracturing technology for horizontal wells is an effective method for the efficient development of shale gas. It improves fracturing effectiveness and enhances production potential by adjusting the length of fracturing stages and optimizing fracturing parameters. However, traditional fracturing design methods do not account for differences in reservoir resource abundance or the impact of complex geological structures.This study meticulously divides the marine shale gas reservoir into eight levels based on three factors: reserve enrichment, rock brittleness, and the development degree of natural fractures and bedding. A horizontal well full-section sweet spot identification method, considering the "Geology-Engineering-Fracture Network Construction Potential" (Three Sweet Spots), is proposed. Moreover, targeted reservoir stimulation techniques are assigned to sections with different sweet spot levels. With the goal of maximizing stimulated reservoir volume (SRV), optimal fracturing parameters are calculated for each technique, resulting in a differentiated fracturing design method based on stage and cluster.The "Three Sweet Spots" identification method effectively reveals the distribution characteristics of reservoir-rich areas and regions suitable for fracture network construction along the entire wellbore section. Based on the identification results, stage-cluster parameters are adjusted to optimize the fracturing design. For sweet spot levels 1–4, which have higher resource abundance, the production potential of favorable reservoirs is maximized through strategies such as reducing stage length, increasing Liquid-injected Volume per meter and Sand-injected Volume per meter. For sweet spot levels 5–8, which have lower resource abundance, more economical methods, such as increasing stage length and perforation cluster density, are recommended for the effective development of surrounding reservoirs. The final design well achieved a 7.8% increase in Estimated Ultimate Recovery (EUR) compared to neighboring wells, demonstrating the applicability of the "Three Sweet Spots" identification method in the southern Sichuan region.This paper provides new insights and approaches for optimizing fracturing parameters in horizontal wells by fully considering the heterogeneous distribution of reservoir resource abundance and rock mechanical properties, offering a new perspective for fracturing design optimization.
Zhao et al. (Mon,) studied this question.