考虑不可逆变形的特低渗油藏不稳定渗流特征

Unsteady flow characteristics considering non-reversible deformation in extra-low permeability reservoir

李 涛

Li Tao

大庆油田有限责任公司勘探开发研究院，黑龙江 大庆 163712

Research Institute of Petroleum Exploration and Development, Daqing Oilfield Company Limited, CNPC, Daqing 163712, China

特低渗油藏在压力变化的条件下，通常发生的是不可逆变形。通过考虑不可逆变形条件下渗透率随压力的变化关系，建立了考虑不可逆变形的特低渗油藏非线性不稳定渗流模型并进行数值求解，从而得到了内边界定产量条件下的压力分布。结果表明，在定产量条件下，随着渗透率下降变化系数的增加，地层压力下降越来越快，井底流压越来越低，极限的供油半径越大。

With the variation of formation pressure, the formation deformation is usually non-reversible in extra-low permeability reservoirs. By considering the connection of permeability change with pressure drop at non-reversible deformation, the non-linear unsteady flow model is established for extra-low permeability reservoir with non-reversible deformation and the numerical solution can be conducted, from which the pressure distributions under the condition of single rate at inner boundary can be obtained. The study results show that the formation pressure decreases faster and faster and that the bottom hole flowing pressure is getting lower and lower with the increasing of variation coefficient for permeability drop at single rate, with the limiting drainage radius increasing.