赣北高、过成熟页岩微观孔隙发育及储气性能研究

发布时间：2018-04-26 04:03

本文选题：赣北 + 高、过成熟页岩　；参考：《中国矿业大学》2017年硕士论文

【摘要】：为研究赣北地区高、过成熟页岩微观孔隙发育特征及其储气性能,论文采用压汞、低温氮气吸附实验方法分析了样品的孔隙结构、孔径分布、比表面积,核磁共振方法测定了样品的孔隙度、渗透率。扫描电镜实验观察了孔隙形态、类型,并结合Arc GIS技术统计分析了孔隙数量、面孔率。并根据实验所得数据探讨了影响赣北高、过成熟页岩孔隙发育的因素,赣北高、过成熟页岩吸附能力的控制因素及赣北高、过成熟页岩储气性能。通过以上研究得出以下结论:(1)赣北高、过成熟页岩孔隙结构多样,有狭缝状、无规则开放孔及墨水瓶孔,其中墨水瓶孔居多。孔径主要分布于微孔、小孔(3~60nm),平均孔径略大。孔隙类型主要为脆性矿物粒间孔、溶蚀孔,同时见大量的有机质孔。比表面积偏小(0.217~16.4283m~2/g,均值7.1734m~2/g),孔隙度较大(0.4%~18.4%,均值4.14%),渗透率较小(0.0025~0.0163×10~(-3)μm~2,均值0.00985×10~(-3)μm~2)。基于Arc GIS孔隙表征发现各孔隙类型的形态多样,孔径大小表现为:脆性矿物孔粘土矿物孔有机质孔的趋势。(2)粘土矿物的含量与类型对高、过成熟页岩孔隙发育都有影响,与孔容呈一定的正相关,与平均孔径、孔隙度呈负相关。而脆性矿物恰好与粘土矿物相反。有机碳含量与孔隙孔容、孔隙度呈正相关。随着干酪根类型由腐泥型到混合型,比表面积、总孔体积变大。有机质成熟度的影响表现为,低成熟阶段到成熟阶段,孔容、孔隙度随着成熟度减小,高、过成熟阶段,孔容、孔隙度随成熟度不断增大,而比表面积整体上随着成熟度的升高而降低。主要是由于低成熟阶段,由于孔容、孔径随成熟度增大而逐渐减小,部分小孔演化为微孔,这个阶段孔隙比表面积会短暂的增加,高、过成熟阶段孔容、孔径随之不断变大,而大孔径对比表面积贡献有限,从而导致比表面积减小。(3)赣北地区高、过成熟页岩样品吸附能力较强。但是赣北高、过成熟页岩的有机质成熟度与气体吸附量呈现出一定程度的负相关,主要原因是高、过成熟阶段,页岩比表面积减小导致吸附能力减弱。有机碳含量、比表面积、孔体积与最大气体吸附量呈正比。不同的有机质类型吸附能力不同,腐泥型小于混合型,腐泥型小于腐植型。孔隙度与甲烷最大吸附量呈负相关关系,而孔隙度直接控制着页岩气的含量大小。表明高、过成熟页岩中页岩气主要是以游离态赋存在孔隙中,相对少的部分以吸附态赋存。
[Abstract]:In order to study the characteristics of micropore development and gas storage performance of high and over mature shale in north Jiangxi Province, the pore structure, pore size distribution and specific surface area of the samples were analyzed by mercury injection and low temperature nitrogen adsorption experiments. The porosity and permeability of the samples were measured by NMR. The pore morphology and type were observed by SEM, and the pore number and porosity were analyzed by Arc GIS technique. Based on the experimental data, the factors affecting the porosity development of the high and over mature shale in northern Jiangxi, the controlling factors of the adsorption ability of the high and over mature shale in the north of Jiangxi and the gas storage performance of the high and over mature shale in the north of Jiangxi are discussed. Through the above research, the following conclusions are drawn: North Jiangxi is high, the pore structure of overmature shale is diverse, there are slit, irregular open pores and ink bottle holes, among which the ink bottle pores are the most. The pore size is mainly distributed in micropores, and the average pore size is slightly larger. Pore types are mainly brittle mineral intergranular pores, dissolution pores, and a large number of organic pores. The specific surface area is small (0.217) 16.4283m/ g, the mean value is 7.1734m/ g / g, the porosity is greater than 0.4m / g / g, and the average value is 4.14g / g, and the average value is 4.14m / g, and the average permeability is 0.002525n0.0163 脳 10 ~ (-3) 渭 m ~ (-2) and the mean value is 0.00985 脳 10 ~ (-3) 渭 m ~ (-2) / m ~ (-1). On the basis of Arc GIS pore characterization, it is found that the pore types are various, and the pore size is: the tendency of organic pore in clay mineral pore of brittle mineral pore. The content and type of clay mineral have influence on the development of pore in overmature shale. There is a positive correlation with pore volume, negative correlation with average pore size and porosity. Brittle minerals are opposite to clay minerals. Organic carbon content is positively correlated with pore volume and porosity. With the kerogen type from saproot to mixed, the specific surface area and the total pore volume become larger. The effect of maturity of organic matter is as follows: from low maturity stage to mature stage, pore volume and porosity decrease with maturity, high, over mature stage, pore volume and porosity increase with maturity. As a whole, the specific surface area decreases with the increase of maturity. It is mainly due to the low maturity stage, the pore volume and pore size gradually decrease with the increase of maturity, and some of the pores evolve into micropores. At this stage, the specific surface area of the pores will increase briefly, and the pore volume will become larger in the over-mature stage, and the pore size will become larger and larger. However, the large pore size has a limited contribution to the specific surface area, which leads to the decrease of the specific surface area. However, the organic matter maturity of the overmature shale is negatively related to the gas adsorption capacity in the north of Jiangxi Province, the main reason is that the adsorption capacity is weakened due to the decrease of the shale specific surface area in the over-mature stage. The organic carbon content, specific surface area and pore volume are directly proportional to the maximum gas adsorption capacity. The adsorption ability of different organic matter types is different, the saproot type is smaller than the mixed type, and the sapropelic type is smaller than the saprophytic type. Porosity is negatively related to the maximum adsorption capacity of methane, and porosity directly controls the content of shale gas. It is shown that shale gas in high and overmature shale mainly occurs in pores in free state and in adsorption in relatively few parts.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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