页岩气富集高产主控因素分析——以四川盆地涪陵地区五峰组-龙马溪组一段页岩为例

Main controlling factors of shale gas enrichment and high yield: a case study of Wufeng-Longmaxi formations in Fuling area, Sichuan Basin

方栋梁 孟志勇

FANG Dongliang MENG Zhiyong

中国石化 江汉油田分公司 勘探开发研究院, 武汉 433124

Exploration and Development Research Institute, SINOPEC Jianghan Oilfield, Wuhan, Hubei 433124, China

以四川盆地涪陵地区五峰组-龙马溪组海相页岩为研究对象，综合岩心观察、地化分析、测井和地震资料，分别从页岩气富集和高产两方面开展主控因素系统分析，明确有机碳含量、微-纳米尺度孔隙和保存条件是页岩气富集主控因素。其中有机碳含量不仅是评价页岩原生品质的重要参数，同时影响微-纳米尺度孔隙发育特征，而保存条件是页岩气富集的重要基础保障。页岩气高产受脆性矿物含量、埋深、构造形态和裂缝因素影响，其中脆性矿物含量越高，页岩可压性越好；页岩埋深及构造形态对于地应力影响较大，从而影响页岩储层的压裂改造效果；裂缝的发育导致压裂过程中压力的定向性泄压，无法形成有效复杂缝网。

The controlling factors of shale gas enrichment and yield were discussed based on core observation, geochemical analysis, logging and seismic data of marine shale collected from the Wufeng-Longmaxi formations in the Fuling area of Sichuan Basin. Total organic carbon content, micro-to nano-scale pores and preservation conditions are the main controlling factors for shale gas enrichment. The total organic carbon content is not only an important parameter for evaluating original shale quality, but also affects micro-to nano-scale pore development. The preservation condition is important for shale gas enrichment. The high yield of shale gas is affected by brittle mineral content, burial depth, structural morphology and fractures. The higher the brittle mineral content, the better the compressibility of shale and the better the effect of fracturing. In addition, burial depth and structure features have great effect on crustal stress, and thus have significant influence on fracturing. Natural fracture development leads to directional pressure relief during fracturing, and it is difficult to form an effective and complex permeability mesh.

国家科技重大专项 2016ZX05060;国家自然科学青年基金项目 41702149

https://doi.org/10.11781/sysydz202001037