构造和水文地质条件耦合作用下煤层气富集高产模式

(1.西安科技大学 地质与环境学院,陕西 西安 710054; 2.国土资源部 煤炭资源勘查与综合利用重点实验室,陕西 西安 710021)

煤层气富集高产; 耦合分析; 构造条件

Enrichment and high-yield models of coalbed methane influenced by geologic structures and hydrologic conditions
CHEN Yue1,MA Dong-min1,2,FANG Shi-yue1,GUO Chen1,YANG Fu2,HOU Dong-zhuang1

(1.College of Geology and Environment,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Key Laboratory of Coal Resource Exploration and Comprehensive Utilization,Ministry of Land and Resources,Xi'an 710021,China)

enrichment and high production of coalbed methane; coupling analysis; structure conditions

DOI: 10.13800/j.cnki.xakjdxxb.2019.0412

备注

构造和水文地质条件对煤层气富集成藏和开发具有重要影响,为研究煤层气富集和产出过程中不同构造和水文地质条件耦合效应,文中以鄂尔多斯盆地东缘为例,通过详细研究不同区块构造、水文地质条件对煤层气富集和产出的影响,总结出构造和水文地质条件耦合作用下煤层气富集模式,并且结合典型煤层气开发区块产能特征提出了有利于煤层气开发的高产模式。结果 表明:逆断层、向斜轴部以及单斜构造下部有利于煤层气的富集保存,而正断层和背斜轴部容易导致煤层气的逸散; 地下水矿化度高的弱径流区、滞留区,有利于煤层气富集; 北部准格尔、保德等低煤阶地区为低煤阶次生生物气补充型富集模式,中部柳林地区为盆缘斜坡带水力封堵型富集模式,南部大宁—吉县地区为构造—水动力复合型富集模式; 提出了弱水动力单斜上倾方向高部位高产模式、弱水动力背斜(或鼻状构造)轴部高产模式以及弱水动力正断层远端构造高部位高产模式3种高产模式。

Structural and hydrological conditions have significant influence on coalbed methane accumulation and development.In order to study the coupling effect of structural and hydrological conditions on coalbed methane enrichment and production,in this paper,taking the eastern margin of Ordos Basin as a case,the accumulation models of coalbed methane in the study area will be summarized,and the high-yield models be presented according to the study of the coalbed methane production characteristics of the typical development blocks,based on the intensive study of the effects of the particular geologic structures and hydrologic conditions on the accumulation and development of coalbed methane in different blocks.The results show that reverse faults,the axial part of syncline and the bottom of monoclinic are favorable for gas enrichment,but gases are easy to escape near normal faults and the axial part of anticline.The stagnant zone and the weak run-off zone with high groundwater mineralization are favorable for coalbed methane enrichment.The secondary biogenic gas supplement model in low coal rank in Zhungger and Baode,the hydraulic sealing model of the slope in the margin of basin in Sanjiao and Liulin,and the structural and hydraulic sealing united model in Daning-Jixian are summarized.Furthermore,three high-yield models are proposed,i.e.,weak hydrodynamic updip of the monocline model,weak hydrodynamic axial part of the anticline or nose-like structure model,and weak hydrodynamic structural high far from the normal faults.