页岩气富集与高产的地质因素和过程

GEOLOGICAL FACTORS AND PROCESS IN ENRICHMENT AND HIGH PRODUCTION OF SHALE GAS

在查阅大量页岩气研究文献的基础上,考虑到页岩气藏的独特性,结合与其它页岩气藏的横向对比,重点剖析并初步总结了影响美国Fort Worth盆地密西西比系Barnett页岩气富集与高产的地质因素,提出了相应的地质过程概念模型,以期对即将到来的中国页岩气的评价、勘探与开发有些许启示。分析认为,在诸多影响因素中,热成熟度、造成页岩易压裂性因素的存在以及二者的有效匹配,是页岩气能否富集与高产的最重要的因素,其地质过程可归纳为3个阶段,即低熟微裂缝开启生物气逸散阶段、高熟微裂缝胶结裂解气富集阶段、压裂微裂缝开启页岩气高产阶段。

Based on referring to a large number of Chinese and foreign literatures, considering the peculiarity of shale gas reservoir and combining with the horizontal comparison with other shale gas reservoir, this paper focuses on analyzing and summarizing the geological factors in enrichment and high production of the Mississippian Barnett shale gas in the Fort Worth Basin of United States. Finally, the related conceptual model of geological process is proposed in order to offer a little inspiration for the assessment, the exploration and the development of Chinese shale gas, which will come. By the analysis of the influ- ential factors, it is concluded that the thermal maturity, the factors which exist？ in shale and make it fractured more easily and the validity matching of the two aspects are the most important factors that determine the enrichment and high production of shale gas. The geological process can be summarized into three stages： the first stage is that organic matter is in low maturity, micro-fractures are opened and biogenic gas is effusion; the second stage is that organic matter is in high maturity, micro-fractures are cemented and the cracked gas is enrichment; the third stage is that micro-fractures are reopened and the shale gas is highly produced under hydraulic fracturing.