中国南方海相页岩孔隙特征及其对气体储集与迁移的制约

发布时间：2018-06-20 01:16

本文选题：页岩气 + 孔隙特征　；参考：《中国地质大学(北京)》2017年博士论文

【摘要】：富有机质龙马溪组和牛蹄塘组海相页岩是中国南方重要的页岩气勘探层位。本文以中国南方黔西北-渝东南地区的两套海相页岩为研究对象,利用中子小角散射技术、低压气体吸附、高压压汞、氦气孔隙测定、场发射扫描电镜、自发吸入实验、饱和扩散实验等技术对页岩的孔隙特征进行表征。本文结合页岩的热演化史和成岩作用,揭示了龙马溪组和牛蹄塘组页岩有机孔和无机孔的演化规律。本文也是首次将中子小角散射技术用于中国海相页岩的显微结构的研究。通过与其他孔隙测量方法的对比来定量计算页岩孔隙度的闭孔率。在页岩中氦气孔隙度和小角中子散射孔隙度均与有机碳含量呈正比,粘土矿物含量主要影响页岩中的宏孔部分。同时得出龙马溪组和牛蹄塘组页岩大多属于集合分形维数特征。越低的集合分形维数意味着页岩具有更低的闭孔率,对应更多的开放孔隙结构。本文系统研究了影响页岩甲烷吸附能力的主控因素,结合不同的地质背景,建立了龙马溪组与牛蹄塘组富有机质页岩气体吸附量与埋藏史的关系模型。在过成熟页岩中仅靠吸附气不能满足页岩气的商业化开发,因此在页岩中游离气的保存情况是实现商业化开采的先决条件。页岩孔隙的连通性控制着页岩气的迁移和开采。本文通过场发射扫描电镜、高压压汞、低压气体吸附、接触角、自发吸入实验和激光剥蚀电感耦合等离子体质谱分析法研究页岩的孔隙连通性。通过去离子水和正葵烷流体的对比可以反映出页岩中亲水孔隙网络和亲油孔隙网络的连通性。研究显示页岩的孔隙连通性是受有机孔和无机孔的发育程度以及彼此的连通程度决定的。不同流体在页岩中的运移同样也受构成页岩孔隙的组分的影响。页岩孔隙的连通性会影响页岩气的保存和最终的采收率。
[Abstract]:Marine shale rich in organic matter in Longmaxi formation and Niulitang formation is an important shale gas exploration horizon in southern China. In this paper, two sets of marine shale from northwestern Guizhou and southeast Chongqing in southern China are studied. The techniques of neutron small angle scattering, low pressure gas adsorption, high pressure mercury injection, helium porosity determination, field emission scanning electron microscopy and spontaneous inhalation experiments are used. Saturated diffusion experiments were used to characterize the pore characteristics of shale. Combined with the thermal evolution history and diagenesis of shale, the evolution of organic and inorganic pores in the shale of Longmaxi formation and Niulitang formation is revealed in this paper. It is also the first time that the neutron small angle scattering technique has been used to study the microstructure of marine shale in China. The closed porosity of shale is calculated quantitatively by comparing with other pore measurement methods. Both helium porosity and small-angle neutron scattering porosity are proportional to organic carbon content in shale, and clay mineral content mainly affects the macroporous part of shale. At the same time, the shale of Longmaxi formation and Niulitang formation belong to aggregate fractal dimension. The lower the set fractal dimension, the lower the closed porosity of shale, corresponding to more open pore structure. In this paper, the main controlling factors affecting the adsorption capacity of shale methane are systematically studied, and the relationship between the adsorption capacity of organic matter rich shale gas and burial history of Longmaxi formation and Niulitang formation is established according to different geological background. The commercial exploitation of shale gas can not be satisfied only by adsorption gas in over-mature shale, so the preservation of free gas in shale is a prerequisite for commercial exploitation. The connectivity of shale pores controls the migration and exploitation of shale gas. The porosity of shale is studied by field emission scanning electron microscopy, high pressure mercury injection, low pressure gas adsorption, contact angle, spontaneous inhalation experiment and laser denudation inductively coupled plasma mass spectrometry. The connectivity of hydrophilic pore network and oil-lipophilic pore network in shale can be reflected by comparison of deionized water and norokitane fluid. The results show that the porosity connectivity of shale is determined by the development of organic and inorganic pores and the connectivity of each other. The migration of different fluids in shale is also affected by the composition of shale pores. The connectivity of shale pores will affect the preservation and ultimate recovery of shale gas.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P618.13

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