地层压力梯度对煤层含气性控制作用分析  

Analysis on Effect of Formation Pressure Gradient on Gas Bearing Property of Coal Seam

作　　者：贾宏伟 JIA Hongwei(Inner Mongolia Coal Geological Exploration(Group)109 Co.,Ltd.,Hailar 021008,China)

机构地区：[1]内蒙古煤炭地质勘查(集团)一零九有限公司,内蒙古海拉尔021008

出　　处：《煤炭技术》2024年第11期135-139,共5页Coal Technology

基　　金：国家科技重大专项(2016ZX05044);内蒙古地勘基金项目(17-1-NY01)。

摘　　要：基于国内典型区块的含气性和地层压力梯度数据,从全国层面总结分析了异常高压区、异常低压区和正常压力区的含气性特点,同时以滇东黔西地区为例开展了实证分析,通过点面结合系统总结了地层压力梯度对含气性的影响作用。研究表明,异常高压区煤层含气性相对较好,我国大部分异常高压主控下形成的高含气量储层都为自封闭控制型,极少数为水动力封闭型。构造抬升和剥蚀是形成异常低压的环境,极不利于煤层气保存。正常压力区含气量和饱和度也有较为明显的高低差异,水文地质条件、顶底板性质、构造特征等发挥了控制作用。针对滇东黔西地区的实证分析显示,松河井田为自封闭型高压储层,含气量和含气饱和度明显高于低压-常压区的恩洪区块;恩洪区块内部EH-01/02井为构造抬升区,抬升剥蚀形成的异常低压,使其含气量和含气饱和度显著低于常压区井(EH-C6井)。Based on the gas content and formation pressure gradient data of typical blocks in China,the gas content characteristics of abnormal high pressure areas,abnormal low pressure areas and normal pressure areas are summarized and analyzed from the national level.At the same time,an empirical analysis is carried out in the east Yunnan and west Guizhou areas,and the influence of formation pressure gradient on gas content is summarized through a point to point combination system.The study shows that the coal seam in the abnormal high pressure area has relatively good gas content,and most of the high gas content reservoirs formed under the abnormal high pressure control are self-sealing control type,and very few are hydrodynamic sealing type.Tectonic uplift and denudation are the abnormally low pressure environments which are not conducive to the preservation of coalbed methane.The gas content and saturation in the normal pressure area also have obvious differences,and the influencing factors of formation pressure gradient such as hydrogeological conditions,properties of coal seam roof and floor,and structural characteristics play a controlling role.The specific analysis of the east Yunnan and west Guizhou areas shows that Songhe well field is a self-enclosed high-pressure reservoir,and the gas content and gas saturation degree are obviously higher than the Enhong block in the low to normal pressure area.Well EH-01/02 in Enhong block is a tectonic uplift area.Abnormal low pressure caused by uplift denudation makes its gas content and gas saturation significantly lower than that of well EH-C6 in normal pressure area..

关 键 词：煤层气 地层压力梯度 含气量 含气饱和度 

分 类 号：TD712[矿业工程—矿井通风与安全] P618.13[天文地球—矿床学]