Characteristics and Dominant Factors for Natural Fractures in Deep Shale Gas Reservoirs: A Case Study of the Wufeng-Longmaxi Formations in Luzhou Block, Southern China

Abstract In southern Sichuan Basin, the main production layers are characterized by deeply buried, high stress difference, and complex structural conditions. The Luzhou area is far from large faults, natural fractures greatly important for shale gas storage production. Multi-scale control migration, enrichment, preservation conditions of gas, facilitate formation fracture network under action hydraulic fracturing. this study, based on outcrops, drilling cores, geochemical tests, thin section, other experiments, development characteristics Wufeng-Longmaxi in block, Southern China, statistically analyzed, controlling factors (e.g., tectonic factors, organic matter, mineral components, mechanical properties) discussed details. Fractures observed outcrops mainly regional with two groups orthogonal joints. Similarly, core also joints perpendicular to laminae three typical features (high-density, high-angle, unfilled). detail, steeply dipping (75-90°) account 78.1% all fractures, 85.1% being unfilled, having a longitudinal extension less than 4 cm, 65.1% spacing 2 cm. brief, there exist cross-scale similarity among microscopic sections, which critical Based understanding, further research conducted relationship between density content, shows that (i) when 122 number/m, TOC content together positively dominate content; (ii) exceeds appears negative density, not factor anymore. above study establishes quantitative limits block. It may assist providing references determining sweet spot deep exploration Basin.