低渗透煤层气水两相非线性渗流数学模型及计算分析  

A Mathematical Model for Gas-water Two-phase Nonlinear Flow in Low Permeability Coal Reservoirs and Calculation Analysis

作　　者：朱维耀[1] 董熇[1] 宋洪庆[1] 杨焦生[2] 岳明[1] 

机构地区：[1]北京科技大学土木与环境工程学院,北京100083 [2]中国石油勘探开发研究院廊坊分院.河北廊坊065007

出　　处：《科技导报》2013年第22期36-39,共4页Science & Technology Review

基　　金：中央高校基本科研业务费专项基金项目(FRF-TP-12-003A);中国石油科技创新基金项目(2010D50060201)

摘　　要：在考虑煤层气解吸和扩散效应及启动压力梯度的基础上,对低渗透煤层气藏流体输运特性进行分析,建立了低渗透煤层气水两相非线性渗流数学模型,推导出非线性渗流阶段气水两相的控制方程组。通过实例计算表明,液相拟启动压力梯度从0.001MPa/m增加至0.007MPa/m,煤层产气峰值下降约15%;不考虑启动压力梯度时的产气峰值量要比液相拟启动压力梯度为0.001MPa/m的产气峰值提升约7%。因此启动压力梯度的存在阻碍了裂隙中流体的流动,对煤层气开发影响较大。The transport behavior of fluids in low permeability coalbed methane reservoirs is analyzed with considerations of the desorption and diffusion effects of the coalbed methane and the threshold pressure gradient. A mathematical model for gas-water two-phase nonlinear flow is established for low permeability coal reservoirs. The governing equations for the gas-water two-phase nonlinear flow are derived. The case study shows that, when the liquid phase threshold pressure gradient is increased from 0.001MPa/m to 0.007MPa/m, the maximum gas production of coal reservoirs is reduced by nearly 15% ; compared with the liquid phase threshold pressure gradient of 0.001MPa/m, the maximum gas production without the threshold pressure gradient is increased by nearly 7% and the cumulative gas production also has a certain extent of increase. Therefore the existence of the threshold pressure gradient makes the fluid in fractures more difficult to flow and leads to a low production rate. The case study shows that the mathematical model of the gas-water two-phase nonlinear flow could provide a theoretical basis for defining a reasonable gas-well deliverability of low permeability coal reservoirs.

关 键 词：煤层气 非线性 数学模型 拟启动压力梯度 

分 类 号：P618.11[天文地球—矿床学]