考虑解吸作用的低渗透煤层中双重介质渗流理论研究  

Study on Dual Porosity Media Seepage Theory with Desorption for Low Permeability Coal Seam

作　　者：牛丛丛 鞠斌山[1] NIU Cong-cong;JU Bin-shan(School of Energy Resources,Beijing Key Laboratory of Evaluation of Energy Resources and Development Engineering of Unconventional Natural Gas,Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism,Ministry of Education,China University of Geosciences(Beijing),Beijing)

机构地区：[1]中国地质大学(北京)能源学院,非常规天然气能源地质评价与开发工程北京市重点实验室,海相储层演化与油气富集机理教育部重点实验室,北京100083

出　　处：《科学技术与工程》2018年第11期74-81,共8页Science Technology and Engineering

基　　金：国家科技重大专项(2016ZX05011-002)资助

摘　　要：根据煤层低渗透和赋存特征,考虑启动压力梯度及解吸的影响,建立了煤层非稳态窜流方式的双重介质渗流模型。利用基于delaunay网格的有限体积法(FVM)对模型进行求解,得到了双重介质低渗透煤层试井理论曲线,并分析了模型在不同地质参数情况下的双对数曲线的特征。结果表明:基质储能系数越大,对生产越有利。只有当压力梯度大于启动压力梯度时,流体才能流动。解吸现象的存在延缓了煤层中压力波的传播,因此煤层气(CBM)开发早期需要缓慢排水,尽可能将压力降落传播到较大范围形成面积降压,有利于提高CBM的最终采收率。According to the characteristics of low permeability and occurrence in coal seam,the unsteady crossflow of dual porosity seepage model which considers the effects of starting pressure gradient and desorption is established.The model was solved by finite volume method(FVM)on delaunay to gain the type curves of dual porosity media in low permeability coal seam,and the characteristics of double logarithmic curves under different geological parameters were analyzed.The results show:the larger storage coefficient of matrix is better for production.Only when the pressure gradient was greater than the starting pressure gradient can fluid flow.The phenomenon of desorption delays the propagation of pressure wave in coal seam.Therefore,the early development of coal bed methane(CBM)requires drainage slowly.The ultimate recovery of CBM can be improved by spreading the area of pressure propagation.

关 键 词：煤层气 双重介质 启动压力梯度 解吸 有限体积法 

分 类 号：TE371[石油与天然气工程—油气田开发工程]