页岩气直井非稳态非线性渗流的数值计算及产能预测  

Numerical computation for nonlinear unsteady percolation of shale gas and prediction of production

作　　者：刘嘉璇[1] 尚新春[1] 朱维耀[2] 

机构地区：[1]北京科技大学应用力学系,北京100083 [2]北京科技大学环境工程系,北京100083

出　　处：《中国科学：技术科学》2015年第7期737-746,共10页Scientia Sinica(Technologica)

基　　金：国家重点基础研究发展计划(批准号:2013CB228002)资助项目

摘　　要：结合我国南方海相页岩气藏的实际,针对页岩气藏的特殊孔隙结构及多尺度流动的特征,首先由Knudsen数判断出储层主体流态为滑移流,并指出页岩气在页岩多孔介质中的传输过程是一个等温过程.然后修正了Beskok-Karniadakis二阶近似模型,建立了致密页岩气直井平面径向非稳态非线性渗流问题的数学模型.进一步应用玻尔兹曼变换将问题简化,并给出了求解压力场的数值离散显式迭代格式.最后数值计算得到了内边界定压条件下直井的压力场随时间、空间分布曲线,预测了产量随时间变化的规律,并分析了解吸、滑移和扩散效应对产量的影响.According to the reality of the marine shale reservoirs in South China, multi-scale gas flow in the shale reservoirs with special pore structure characteristics is considered. By using the Knudsen number, it is judged that the dominant pattern of flow in shale porous media is slip flow, and it is pointed out that the process of gas transport is an isothermal process. On the basis of multiscale Beskok-Karniadakis flow model, the corresponding second-order approximation correction is given and the mathematic model of nonlinear unsteady radial percolation is established for the tight shale gas wells. The problem is simplified by applying the Boltzmann transformation and an explicit iteration scheme to solve the pressure is presented by numerical discrete technique. The distribution curves of pressure with time and space are obtained for the case of the constant pressure at the inner boundary. The variation of output over time is predicted and the influence of desorption, slippage and diffusion on the production is analyzed.

关 键 词：页岩气 非线性渗流 非稳态径向流 解吸 滑移 扩散 产能预测 

分 类 号：P618.13[天文地球—矿床学]