启动压力梯度动态变化对IPR方程影响分析

Effect of Starting Pressure Gradient Dynamic Change on IPR Equation

基于低渗非达西渗流理论及对Kro/μoBo函数形态的分析,推导了低渗透油藏饱和及未饱和状态下的无因次流入动态方程。在考虑由于原油组分、极限剪切应力等因素随开发变化,启动压力梯度动态变化的前提下,对影响无因次流入动态的因素进行了敏感性研究。结果表明,低渗透油藏中启动压力梯度、污染程度、供给半径和地层平均压力对无因次流入动态都有较显著的影响,同时启动压力梯度的动态变化可显著改变敏感性分析结果。某低渗透油田的测试分析结果表明,该IPR方程能有效评价启动压力梯度动态变化对油井动态的影响。无因次流入动态方程及考虑启动压力梯度动态变化的敏感性分析结果可为开发低渗透油藏提供理论依据。

Based on the non-Darcy percolation theory in low permeability reservoirs and analysis of Kro/Boμ, the dimensionless IPR equations for low permeability reservoirs in saturated and unsaturated conditions were derived. The sensitivity studies on the parameters impacting the inflow performance were conducted, including the change of oil component and limit shear stress with the reservoir development and the dynamic change of staring pressure gradient. The results suggest that starting pressure gradient, skin factor, supply radius and average reservoir pressure have a remarkable effect on inflow performance in low permeability reservoirs. And the dynamic change of starting pressure gradient can significantly influences the results of sensitive analysis. The testing results of a low permeability reservoir indicate that this IPR e quation can effectively evaluate the impact of starting pressure gradient on inflow performance. This dimensionless IPR equation and the results of sensitive analysis considering the change of starting pressure gradient can provide theoretical basis for the development of low permeability reservoirs.