页岩气储层特征及含气性主控因素——以湘西北保靖地区龙马溪组为例

发布时间：2018-02-12 09:44

本文关键词： 页岩气孔隙裂缝龙马溪组湘西北保靖地区　出处：《岩性油气藏》2017年03期 　论文类型：期刊论文

【摘要】：湘西北保靖地区龙马溪组富有机质泥页岩是重要的页岩气勘探层位。为研究其页岩气储层特征和气体赋存规律,利用矿物组分、有机地球化学、物性、含气性、等温吸附、扫描电镜和Nano-CT扫描等测试资料,并结合野外地质调查,分析和探讨了龙马溪组岩相特征、储层特征及储层含气性主控因素。结果表明:龙马溪组发育3种岩相,分别为炭质-粉砂质泥页岩相、炭质泥页岩相、含炭泥质粉砂岩相;储层孔隙类型主要包括粒间孔、溶蚀孔、晶间孔、化石孔、有机质孔和微裂缝,其中裂缝类型主要为构造缝和成岩缝;孔隙按孔径大小可分为微孔、介孔和宏孔,介孔占总孔容的比重最大,其次是微孔,宏孔最少。综合分析认为:微孔孔容、页岩比表面积与甲烷最大吸附量呈正相关性,受控于页岩有机质含量(TOC);微裂缝与页岩含气量也呈正相关性,说明微裂缝的发育程度对页岩含气性具有影响作用。利用Nano-CT扫描结果,认为绝大部分气体流动空间位于有机质孔隙以及微裂缝中。TOC和微裂缝的发育程度是该区龙马溪组页岩气富集的主控因素。
[Abstract]:The organic clay shale of Longmaxi formation is an important exploration horizon of shale gas in Baojing area, northwest of Hunan Province. In order to study its shale gas reservoir characteristics and gas occurrence law, mineral components, organic geochemistry, physical properties, gas-bearing properties, isothermal adsorption are used. The lithofacies characteristics, reservoir characteristics and main controlling factors of gas-bearing properties of the Longmaxi formation are analyzed and discussed in combination with the test data of scanning electron microscope and Nano-CT scanning, and combined with field geological investigation. The results show that three lithofacies are developed in the Longmaxi formation. The reservoir pore types mainly include intergranular pore, dissolved pore, intergranular pore, fossil pore, organic pore and microfracture. The fracture types are mainly structural fractures and diagenetic fractures, the pores can be divided into micropores, mesoporous and macro pores according to pore size, the proportion of mesoporous to total pore volume is the largest, followed by micropore and macro pore. The specific surface area of shale is positively correlated with the maximum adsorption capacity of methane, which is controlled by the content of organic matter in shale, and the microfracture is positively correlated with the gas content of shale. It shows that the development of microfractures has an effect on the gas content of shale. Using the Nano-CT scanning results, It is considered that most of the gas flow space is located in the pores of organic matter, and the development of .TOC and microfractures in the micro-fractures is the main controlling factor for shale gas enrichment in Longmaxi formation in this area.
【作者单位】：神华地质勘查有限责任公司;中国石油大学(北京)非常规天然气研究院;
【基金】：国家自然科学基金项目“云质岩致密油储层微米—纳米孔喉网络体系及其流体耦合流动机理与流动下限”(编号:41372145)资助
【分类号】：P618.13

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