低渗透油藏不稳定渗流的近似解法

低渗透油藏的开发应该同时考虑启动压力梯度和应力敏感。目前考虑两者的不稳定渗流数学模型解法十分繁琐，主要原因是控制方程具有强烈的非线性，同时流体流动边界并非恒定不变。为了简化计算，利用油藏压力分布近似表达式，研究得到同时考虑这2个因素的低速非线性不稳定渗流压力分布特征；根据物质平衡原理，利用牛顿迭代方法计算得到了定产量、变产量和定流压生产情况下动边界运动规律以及井产量的变化规律。计算分析表明，启动压力梯度增加了地层的渗流阻力，介质变形削弱了近井地带地层的导流能力，使得地层能量不易被释放出来，两者均增大了油藏的开发难度。

A DISCUSSION ON CONFLICT WITH ONE ANOTHER IN CONTENT AND OTHER PROBLEMS

The two factors of TPR（threshold pressure gradient）and stress sensitivity should be considered in low permeability reservoir development.Because of strong nonlinear property of control equation and nonconstant boundary of fluid flow,the mathematical model used now is very tedious.In order to simplify calculation process，the characteristic of instability,low speed and nonlinear flow pressure distribution are obtained with reservoir pressure distribution approximate formula.Meanwhile,the motion law of flowing boundary and the distribution of formation pressure,as well as variation law of production rate are gained based on material balance principle under the condition of constant flow rate.Calculation results show that TPR increase flow resistance in porous media and media deformation decreases conductivity near the well bore formation,which result in formation energy can not be released and add to the difficulty of lowpermeability reservoir exploitation.