【作者】 李刚；

【导师】 郭英海；

【作者基本信息】 中国矿业大学 ， 地质工程（专业学位）， 2023， 硕士

【摘要】 论文基于宁夏石嘴山矿区煤层气勘探、工程实践,结合煤岩样测试,研究了区内主要煤储层的煤储层特征、煤层气富集规律,探讨了煤层气富集的地质控因,评价了其开发潜力。主要结论如下:(1)阐明了研究区主要煤储层的一般特征。研究区主要煤储层为中灰～高灰、中热值煤,最大镜质组反射率在0.984%-1.067%之间,属Ⅲ变质阶段的烟煤;5煤和6煤孔裂隙发育较好,属于中渗储层。(2)揭示了研究区主要煤层的煤层气富集规律。研究区煤层气资源丰富,主要煤层煤层气资源总量达79.73×10~8m~3,资源丰度1.88×10~8m~3/km~2。主要煤层中5煤、6煤、7煤吸附能力最强;5煤、6煤含气量最大,介于3.79～10.44m~3/t之间,垂向上从2煤到6煤随深度增大含气量呈上升趋势,但从6煤到9煤含气量呈下降趋势;空间上自向斜轴部向两翼呈递减趋势。(3)剖析了研究区煤层气富集的地质控因。煤岩煤质中,镜质组含量、变质程度与含气量成正相关;在储层物性上,孔裂隙发育与含气量密切相关,5煤、6煤裂隙极其发育,含气量最高。沉积环境影响着煤层的宏观煤岩及有机组分、煤层厚度、盖层条件等。研究区整体为向斜构造,轴部地应力明显大于两翼,水力封堵影响在向斜两翼表现明显。各煤层的煤层气含量自向斜轴部向两翼呈递减趋势。垂向上2、3、5、6煤随深度增加含气量增高,7、9煤含气量相对降低。对保存条件而言,地质控制因素的影响大小为:构造>沉积环境>水文地质条件,表现为各煤层气含量随煤层埋深的增加而增大;含气量轴部大于两翼,并有明显递减趋势。(4)对研究区煤层气的潜力进行了评价。分析了排采井产能,根据研究区煤储层的物性特征,采用模糊综合评判的方法评价了煤层气资源量及开发潜力。更多还原

【Abstract】 Based on the data of coalbed methane exploration and engineering practice in Shizuishan mining area of the Ningxia area,combined with the test results of coal samples,the thesis studies the reservoir characteristics of main coal reservoirs and the law of coalbed methane enrichment,discusses the geological factors of coalbed methane enrichment,and evaluates the development potential of the study area.The main conclusions are as follows:(1)The general characteristics of main coal reservoirs in the study area are expounded.The main coal reservoirs in the study area are medium to high ash and medium calorific value coal,with a maximum reflectance of vitrinite ranging from0.984%to 1.067%,which belongs to bituminous coal in the coal metamorphic stageⅢ;No.5 coal seam and No.6 coal seam are well developed and belong to medium permeability reservoir.(2)The CBM enrichment law of main coal seams in the study area is revealed.The total amount of coalbed methane resources in the main coal seams is 79.73×10~8m~3,and the resource abundance is 1.88×10~8m~3/km~2.Among the main coal seams,No.5 coal seam,No.6 coal seam and No.7 coal seam have the strongest adsorption capacity;the gas content of No.5 coal seam and No.6 coal seam is the largest,which is between 3.79 m~3/t and 10.44 m~3/t.In the vertical direction,the gas content increases with depth from No.2 coal seam to No.6 coal seam,but decreases from No.6 coal seam to No.9 coal seam.In the space,it shows a decreasing trend from the syncline axis to the two wings.(3)Analyzed the geological controls for coalbed methane accumulation in the study area.The content of vitrinite group in coal and its degree of metamorphism are positively correlated with gas content.In terms of reservoir properties,the development of fractures is closely related to gas content,with coal seams 5 and 6having particularly well-developed fractures and the highest gas content among all coal seams.Sedimentary environment affects the macroscopic coal rock and organic components,coal seam thickness,and cap rocks conditions,etc.The study area is characterized by a synclinal structure,with a decreasing trend of coalbed gas content from the axis towards both sides.The in-situ stress in the axis of the syncline is significantly greater than that in the two wings.The gas content of 2,3,5 and 6 coal increases with the increase of depth,and the gas content of 7,9 coal decreases relatively due to the influence of hydraulic plugging.For preservation conditions,the influence of geological control factors is as follows:structure>sedimentary environment>hydrogeological conditions.The manifestation was that the content of coalbed methane increased with the increase of the buried depth of the coal seam.The gas content in the axis is greater than that in the two wings,and there is a significant decreasing trend.(4)The potential of coalbed methane in the study area was evaluated.The production capacity of drainage wells was analyzed.Based on the physical characteristics of the coal reservoir in the research area,the fuzzy comprehensive evaluation method was used to evaluate the CBM resources and development potential.更多还原