沁水盆地郑庄区块残存煤层气的埋深和构造综合控气模式分析

Analysis of Residual Coalbed Methane Burial Depth and Structural Comprehensive Gas Control Model in Zhengzhuang Block of Qinshui Basin

煤层含气量是影响煤层气勘探开发的重要条件.实际生产中,煤储层地质条件十分复杂,含气量往往受多个因素综合控制.以沁水盆地郑庄区块3^(#)煤层为研究对象,分析其含气量分布特征及控气地质因素,得到以下结论:郑庄区块煤层含气量较高,其分布特征受煤层埋深和构造条件综合作用;在构造条件不发育地区,煤层埋深通过改变储层温度和压力控制煤层气的产生和保存,随着埋深增加,煤层含气量先增加后降低,逐渐由强压力敏感性转变为强温度敏感性;在构造发育区域,煤层含气量受埋深和构造条件综合作用,构造条件通过改变煤层埋深和储层封闭能力引起煤层气的运移逸散,褶皱和断层作用改变煤层埋深,为煤层气运移提供驱动力,伴生的节理是煤层气的运移通道,其走向和密度控制煤层气的运移方向和程度,运移目标区的埋深等储层特征影响煤层气的最终保存.

Coal seam gas content is an important condition affecting the exploration and development of coalbed methane.In actual production,the geological conditions of coal reservoirs are very complex,and the gas content is often controlled by multiple factors.This article takes the 3^(#)coal seam in the Zhengzhuang block of the Qinshui Basin as the research object,analyzes its gas content distribution characteristics and gas control geological factors,and the following conclusions are obtained:The gas content of the coal seam in Zhengzhuang block is high,and its distribution characteristics are affected by the comprehensive effect of coal seam burial depth and structural conditions.In areas where tectonism conditions are not developed,the coal seam burial depth controls the gen-eration and preservation of coalbed methane by changing the reservoir temperature and pressure,and with the increase of burial depth,the coal seam gas content increases first and then decreases,and gradually changes from strong pressure sensitivity to strong temperature sensitivity.In the tectonism development area,the coal seam gas content is affected by the comprehensive effect of buried depth and tectonism conditions,the tectonism conditions cause the migration and escape of coalbed methane by changing the buried depth of the coal seam and the sealing ability of the reservoir,and the folding and fault action change the buried depth of the coal seam,which provides the driving force for the migration of coalbed methane,and the associated joints are the migration channels of coalbed methane,and its trend and density control the direction and degree of coalbed methane migration,and the reservoir characteristics such as the buried depth of the migration target area affect the final preservation of coalbed methane.