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Environment and Resource
ISSN Print:2707-2398
ISSN Online:2707-2401
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四川盆地南部深层页岩气富集主控因素以及成藏模式分析
Main Controlling Factors and Hydrocarbon Accumulation Model of Deep Shale Gas Enrichment in the Southern Sichuan Basin
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Information:
中国石油川庆钻探工程有限公司地质勘探开发研究院，成都
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Keywords:
Deep–ultradeep; Shale gas enrichment; Main controlling factors; Accumulation model深层-超深层; 页岩气富集; 主控因素; 成藏模式
- Abstract: The Wufeng–Longmaxi Formations in the Luzhou area of the Sichuan Basin possess significant potential for shale gas resources. However, considerable variations in shale reservoir quality and gas content exist across different structural units. Natural fracture development and tectonic reworking strongly influence the enrichment patterns, structural controls, and accumulation models of shale gas. Based on logging interpretation, geophysical prediction, core analysis, laboratory test data, and focused ion beam scanning electron microscopy (FIB-SEM) of deep shale samples from the Wufeng–Longmaxi Formations in the Luzhou area, a shale gas enrichment and accumulation model was established. The results indicate that: (1) The variations in deep shale gas reservoirs are attributed to the combined influence of reservoir space characteristics, diagenesis, structural position, tectonic evolution, and fracture–fluid interactions. Organic-rich siliceous shales retain favorable reservoir properties, characterized by organic matter pores that dominate the pore structure, relatively high porosity and permeability, and good pore preservation and gas-bearing capacity under overpressure conditions. (2) Structural style is a primary control on variations in gas content, with synclines exhibiting significantly better gas content than anticlines. Free gas migration governs the enrichment pattern: high fluid pressure in syncline cores drives free gas migration toward anticlines. High gas content zones develop in the core and flanks of synclines where structural integrity is maintained, whereas gas content declines near fault zones in anticlinal areas. (3) Shale gas enrichment relies on the coupled interaction of “high organic carbon content, high-quality pore reservoirs, and strong tectonic preservation conditions.” Syncline cores are typically distant from faults and exhibit good structural integrity and preservation conditions. Driven by buoyancy and other factors, free gas migrates laterally from structurally low areas to adjacent high-position anticlines, while a certain amount of free gas is retained on syncline flanks. Syncline structures are more favorable for shale gas preservation than anticline structures. 四川盆地泸州地区五峰组—龙马溪组页岩气资源潜力巨大，不同构造单元页岩储层品质、含气性差异较大，天然裂缝发育特征、构造改造作用对页岩气富集规律、构造控制作用及成藏模式影响较大。采用泸州地区深层页岩气五峰组—龙马溪组测井解释、物探预测、岩心分析化验资料，以及聚焦离子束扫描电镜等技术，建立页岩气富集成藏模式。研究结果表明：深层页岩气藏储层差异主要受储集空间特征、成岩作用、构造位置、构造演化和裂缝-流体活动共同控制，富有机质硅质页岩仍保持良好储集性能，表现为有机质孔主导的孔隙结构、相对较高的孔隙度和渗透率，超压保孔含气性较好；构造样式主导含气性差异，向斜区显著优于背斜区，游离气运移控制富集格局，向斜区核部流体高压驱动游离气向背斜区运移，向斜区核部、翼部因构造完整形成高含气量带，背斜区域靠近断层含气量降低；页岩气富集依赖“高有机碳物质基础-优质孔隙储集空间-强构造保存条件”的协同配置。向斜核部远离断层，构造完整性和保存条件较好，低部位的游离气在浮力等因素的影响下向两侧高部位背斜区发生侧向运移，一定量的游离气在向斜区翼部保存下来，向斜构造相对于背斜构造更有利于页岩气的保存。
- DOI: 10.35534/er.0802019 (registering DOI)
- Cite: 黎菁，刘兴，龚鑫，等．四川盆地南部深层页岩气富集主控因素以及成藏模式分析［J］．环境与资源，2026，8（2）：144-152.
