滇东地区煤储层精细描述及影响因素分析

发布时间：2018-05-17 20:47

本文选题：滇东地区 + 储层　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：滇东的老厂、恩洪矿区是滇东重要的产煤区,也是我国重要的煤层气富集地带。为了精细描述该地区的煤储层特征及其主控因素,论文在前期研究的基础上结合扫描电镜、显微组分、工业分析等实验,系统的分析了煤储层的煤岩煤质特征。通过低温液氮、等温吸附、核磁等实验,系统的分析了煤储层的孔裂隙发育、含气量以及吸附特征;并结合前人研究成果,综合研究了煤储层物性特征及其储集特征的影响因素,得出以下几点结论:(1)显微组分以及工业分析实验表明,所取样品的宏观煤岩特征均为半亮煤、半暗煤,且半亮煤占多数,这与其研究区煤层的有机质以镜质组为主相吻合。老厂矿区煤样的灰分产率要略小于恩洪矿区,且同一煤层的上部灰分产率一般大于下部,煤中的硫元素主要为无机硫。(2)低温液氮吸附实验显示研究区的孔隙主要以微孔和小孔最为发育,其中小孔和中孔贡献了70%以上的孔体积,微孔贡献了50%以上的比表面积。煤样的吸附脱附曲线可以分为三类,且老厂矿区同一储层不同位置的样品的吸附脱附曲线差别较大,尤其是7#煤,说明研究区部分煤储层内部孔隙结构非均质性较大。(3)通过核磁实验将样品图谱分为三类:吸附孔连通型、吸附孔闭塞型以及渗流孔裂隙发育型,三类图谱所对应的有效、残余孔隙的比值分别约为40%、60%,20%、80%以及75%、25%;恩洪矿区焦煤中的渗流孔以及裂隙的发育程度要远远好于老厂矿区的无烟煤,孔隙度计算结果显示老厂煤储层孔隙度差异较大。(4)老厂矿区煤储层的含气量要高于恩洪矿区,恩洪矿区煤层气具有湿气特点,老厂矿区含气量与埋深的相关性要好于恩洪矿区;老厂矿区煤储层的兰氏体积大于恩洪矿区,说明其吸附能力也要好于恩洪矿区;研究区煤储层的含气量随煤变质程度的增加而增加。(5)吸附实验以及低温液氮实验显示:老厂矿区2#煤的兰氏体积要小于7#煤,但是2#煤的BET比表面积及BJH总孔容要大于7#煤。初步断定老厂7#煤小于2nm的超微孔发育情况要好于2#煤。(6)煤储层裂隙的发育主要受构造的影响,孔隙发育与煤储层的煤质关系密切。
[Abstract]:Enhong mining area is an important coal-producing area in eastern Yunnan and an important coalbed methane enrichment zone in China. In order to describe the characteristics of coal reservoir and its main controlling factors in this area, based on the previous research, this paper systematically analyzed the coal and rock coal quality characteristics of coal reservoir based on the experiments of scanning electron microscope, macerals and industrial analysis. Through experiments of low temperature liquid nitrogen, isothermal adsorption, nuclear magnetic field and so on, the development of pore and fissure, gas content and adsorption characteristics of coal reservoir are systematically analyzed. This paper comprehensively studies the physical properties of coal reservoir and the influencing factors of its reservoir characteristics, and draws the following conclusions: (1) the macerals and the industrial analysis experiments show that the macroscopic coal and rock characteristics of the samples are all semi-bright coal, semi-dark coal, and semi-bright coal are the majority. This coincides with the vitrinite as the main organic matter in the coal seam in the study area. The ash yield of coal samples in Laochang mining area is slightly smaller than that in Nhong mining area, and the yield of ash in the upper part of the same coal seam is generally larger than that in the lower part. The experiments of adsorption of sulfur in coal with inorganic sulfur at low temperature show that the pores in the study area are mainly micropores and micropores, in which the pore and mesopore contribute more than 70% of the pore volume and the specific surface area of the micropore is more than 50%. The adsorption and desorption curves of coal samples can be divided into three categories, and the adsorption and desorption curves of samples at different locations of the same reservoir in Laochang mining area are quite different, especially for coal. The results show that the internal pore structure heterogeneity of some coal reservoirs in the study area is relatively large. (3) through nuclear magnetic experiments, the sample maps are divided into three types: the connected type of adsorption pore, the closed type of adsorption pore and the developed type of percolation pore, and the corresponding effectiveness of the three types of atlas is obtained. The ratios of residual pores are about 40%, 60%, 20% and 20%, respectively. The percolation holes and cracks in the coking coal of the Enhong mining area are far better developed than those of the anthracite in the Laochang mining area. The results of porosity calculation show that the gas content of coal reservoir in Laochang mining area is higher than that in Enhong mine area, the coalbed methane in Nhong mine area has the characteristics of wet gas, and the correlation between gas content and buried depth in Laochang coal mine area is better than that in Nhong mine area. The Lansch volume of coal reservoir in Laochang mining area is larger than that in Nhong mine area, which indicates that its adsorption capacity is also better than that in Nhong mine area. The gas content of coal reservoir in the study area increases with the increase of metamorphic degree of coal. The adsorption experiments and low temperature liquid nitrogen experiments show that the Lansch volume of coal in Laochang mining area is smaller than that of coal 7#, but the specific surface area of BET and the total pore volume of BJH of coal in 2# coal are larger than those of coal. It is preliminarily concluded that the development of ultrafine pores in Laochang 7# coal is better than that in 2# coal. 6) the development of fractures in coal reservoir is mainly affected by structure, and pore development is closely related to coal quality of coal reservoir.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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