低压特低渗透油藏采油、采液指数变化规律

Variation of Oil or Liquid Productivity Index in Low-Pressure and Super-Low Permeability Reservoir

针对低压特低渗透油藏较常规低渗透油藏储集层岩石压力敏感性更强的特点,推导了考虑启动压力和渗透率压力敏感性变化下的无因次采油(液)指数计算公式。以吐哈油田牛圈湖低压特低渗油藏为例,讨论了油水粘度比、启动压力和渗透率变形系数动态变化时无因次采油、采液指数与含水率的变化关系。研究结果表明,低压特低渗油藏启动压力的动态变化对无因次采油指数有较明显的影响;此外,无因次采液指数受启动压力和渗透率变形系数的影响也较常规低渗透油藏更为明显。

Low pressure and super-low permeability reservoir is of more rock pressure sensitivity than conventional permeability reservoir.In this paper,the formula for calculation of non-dimensional oil or liquid productivity index by considering changes of starting-up pressure and permeability pressure sensitivity is deduced.Taking Niujuanhu reservoir with low pressure and super-low permeability in Tuha oil field as an example,the variation between non-dimensional oil or liquid productivity index and water cut is discussed when oil-water viscosity ratio,starting-up pressure and permeability deformation factor are changed dynamically.The studied result shows that the dynamic change of starting-up pressure of such a reservoir has obvious effect on the non-dimensional oil or liquid productivity index.Moreover,this index is much more affected by the starting-up pressure and permeability deformation factor than that of conventional low permeability reservoir.