基于保压煤心的瓦斯压力演化规律及其计算方法  

Evolutionary pattern and a calculation method of in situ gas pressure based on pressure-retaining coal cores

作　　者：高明忠 宋杰[1,2] 崔鹏飞 李永程 王智鹏 周雪敏 李炬 郝宗欣 郝海春 GAO Mingzhong;SONG Jie;CUI Pengfei;LI Yongcheng;WANG Zhipeng;ZHOU Xuemin;LI Ju;HAO Zongxin;HAO Haichun(State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,Shenzhen University,Shenzhen 518060,China;Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization,Institute of Deep Earth Sciences and Green Energy,Shenzhen University,Shenzhen 518060,China;College of Water Resource and Hydropower,Sichuan University,Chengdu 610065,China;School of Mechanical Engineering,Sichuan University,Chengdu 610065,China;China Construction First Group the Fifth Construction Co.,Ltd.,Beijing 100024,China)

机构地区：[1]深圳大学深地工程智能建造与健康运维全国重点实验室,广东深圳518060 [2]深圳大学广东省深地科学与地热能开发利用重点实验室,深地科学与绿色能源研究院,广东深圳518060 [3]四川大学水利水电学院,四川成都610065 [4]四川大学机械工程学院,四川成都610065 [5]中建一局集团第五建筑有限公司,北京100024

出　　处：《煤田地质与勘探》2025年第4期18-29,共12页Coal Geology & Exploration

基　　金：国家自然科学基金杰出青年科学基金项目(52225403);深圳市杰出青年基金项目(RCJC20210706091948015);国家重点研发计划课题(2023YFF0615401)。

摘　　要：【目的和方法】煤层原位瓦斯压力是煤矿安全生产以及煤层气资源评估的重要参数。针对现阶段煤层原位瓦斯压力测定周期长、测算结果受多种参数影响等局限,利用自主搭建的保压煤心瓦斯压力演化实验系统,开展了不同含水率下保压煤心等温吸附和扩容解吸实验,在揭示保压煤样瓦斯压力演化规律的基础上,基于“深部煤层原位保压保瓦斯取心工艺”形成的“煤层原位瓦斯压力”理论计算原理,提出了考虑气体压缩因子与含水率的瓦斯压力计算修正模型,并验证了其可靠性。【结果和结论】结果表明:(1)受高瓦斯压力影响,保压空间内瓦斯压力更容易达到新的平衡,在等温吸附过程中瓦斯压力呈阶段性演化特征,保压煤心瓦斯压力先快速下降至某一值,升压后再逐渐趋于平衡。(2)受煤样介孔为主、微孔孔容较大孔隙特征影响,煤中水分含水率越高,煤对瓦斯的吸附阻力越大,从而导致平衡时间拉长,吸附压降值降低。(3)基于不同含水率保压煤心扩容解吸实验计算了煤样瓦斯压力,各含水率下瓦斯压力计算结果平均相对误差分别为2.22%、1.29%、0.39%、0.80%,可见修正后的瓦斯压力计算方法有较高准确度。提出的瓦斯压力计算新方法有望为煤层原位瓦斯压力测定提供可靠、便捷、精准的计算方法。[Objective and Methods] The in situ gas pressure of coal seams represents a crucial parameter for the safe production of coal mines and the assessment of coalbed methane(CBM) resources.To overcome current limitations in determining the in situ gas pressure,such as prolonged measurement cycles and the influence of multiple parameters on the measurement results,this study conducted isothermal adsorption and volumetric expansion desorption experiments on pressure-retaining coal cores with varying moisture contents using a self-constructed experimental system for gas pressure evolution in pressure-retaining coal cores.As a result,the evolutionary pattern of gas pressure in pressure-retaining coal cores was determined.Accordingly,following the theoretical calculation principle of in situ gas pressure in coal seams,formed by the in situ pressure-and gas-retaining coring process for deep coal seams,this study proposed a correction model for gas pressure calculation that considered moisture content and verified its reliability.[Results and Conclusions] The results indicate that:(1) Influenced by high gas pressure,the gas pressure within the pressure-preserved space more easily reaches a new equilibrium.During the isothermal adsorption process,the gas pressure exhibits a staged evolution characteristic,where the gas pressure in the pressure-preserved coal core first rapidly decreases to a certain value,then increases before gradually stabilizing.(2) Due to the pore characteristics of the coal sample being dominated by mesopores and having a large micropore volume,the higher the moisture content of coal leads to greater resistance to gas adsorption,resulting the longer the equilibrium time and the lower the adsorption pressure drop.(3) The gas pressure of the coal samples was calculated based on the expansion desorption experiments of pressure-preserved coal cores with different moisture contents.The average relative errors of the gas pressure calculation results under various moisture contents were 2.22%,1.29%,0.39%,and 0

关 键 词：保压保瓦斯取心 含水率 原位瓦斯压力 压力计算 压力演化 

分 类 号：TD712[矿业工程—矿井通风与安全]