页岩气储层纳米尺度非均质性研究

Shale gas has become the hot topic of unconventional gas development. Shale gas reservoir has geological characteristics of high content of clay mineral, rich in organic matter and organic nano-pores, complex structural components and rocks facies. But the parameters and methods for evaluating heterogeneity of unconventional reservoir such as tight sandstone reservoir can not be simply applied to evaluate shale nano-scale heterogeneity. It is necessary to establish proper methods and means to study on shale nano-scale heterogeneity. This study focuses on the establishment of nano-macro heterogeneity evaluation parameters and methods about the shale particles micro fabric characteristics, nano-scale pore structure characteristics and petrophysical index. By studying evaluation parameters of shale orientation index, organic particles orientation index, hardness index, transverse wave index and so on, and combining with 3D digital core and pore network models, then finding out the key factors by mutual inversion between parameters, establish of nano-scale heterogeneity evaluation parameters and systemfinally. Combining with the evaluation system of macro and micro heterogeneity by previous established, completing a characterization system adapt to multi-scale heterogeneity characterization system of domesticmarine shale gas reservoirs. These accomplishments will be abundant of the basic exploring and developing theory in shale gas reservoirs, including shale gas accumulation, sedimentation and diagenetic, occurrence form and percolation mechanism of shale gas, and have important guiding significance on perfecting shale gas resource assessment methods, guiding the development of stimulation.

页岩气成为非常规天然气发展的热点方向，页岩气储层具有富含粘土与有机质、有机纳米孔隙发育、岩石结构组分与岩相类型复杂等地质特征，致密砂岩等非常规储层的微观非均质性评价体系不能完全适用于页岩纳（微）米尺度的非均质性评价，必须有针对性的建立评价页岩气储层纳米尺度非均质性参数和体系。本研究重点建立能表征页岩颗粒微组构、纳米孔隙结构、岩石物性参数等纳（微米）非均质性参数，拟研究页岩颗粒定向指数、脆性指数、纵横波指数等参数对纳米非均质性的影响程度，结合3D数字岩心及孔隙网络模型，并通过各参数间相互反演，明确控制关键因素，建立纳米尺度非均质性评价参数与体系。结合前人建立的宏观、微观非均质性评价体系，形成一套符合我国海相页岩气储层多尺度连续非均质性表征体系。这些成果将丰富页岩气成藏、沉积与成岩、页岩气赋存形式及渗流机理等勘探开发基础理论，对完善页岩气资源评价方法、增产措施制定等具有重要的指导意义。

围绕页岩微纳米尺度的非均质性展开研究，利用X-射线衍射、场发射扫描电镜、CT、核磁共振等手段开展了页岩的矿物组分、微观孔隙结构、有机质含量、定向指数、脆性指数、自生矿物、含气性、电阻率、纵横波、岩石力学参数等微观特征研究，通过各参数间相关性与差异性评价，优化出一套系统的页岩纳米尺度非均质性评价的关键参数和体系，推荐选用TOC、黏土矿物和脆性矿物含量、孔隙度、含气性、杨氏模式等参数作为非均性评价关键参数，为提高优质页岩气储层钻遇率与优质储层预测提供了技术支撑；公开发表国内外期刊共发表学术论文32篇，其中SCI 14篇，EI 5篇，联合出版学术专著1部，国内授权发明专利5项，获省部级以上科研奖励2项；培养硕博士（后）14人、青年教师2人。研究成果在长宁地区中浅层页岩气、泸州地区深层页岩气等勘探中逐渐得到应用与推广。