低渗透油藏压裂井复合介质渗流规律研究

Study on Seepage Law for Composite Media in Fractured Wells of Low Permeability Reservoir

低渗透油藏地下裂缝分布形态复杂,影响油藏产能计算的因素较多,情况复杂,常规计算方法很难满足工程需要。故此,考虑启动压力梯度和介质变形系数的影响,建立了低渗透油藏压裂井复合介质径向流渗流模型。并根据此模型推导出不同地层及裂缝参数条件下油井产能变化关系。计算结果表明:在不同的裂缝半长和不同的启动压力梯度条件下,油井定压生产的产量都将随着变形系数的增大而减小;在不同的裂缝半长和不同的介质变形系数条件下,油井定压生产的产量都将随着启动压力梯度的增大而减小;在不同的启动压力梯度和不同的介质变形系数条件下,油井定压生产的产量都将随着裂缝半长的增大而增大。根据本文所建立的复合介质径向流渗流数学模型,能够计算低渗透变形介质地层压裂井的产量压力变化规律,该模型具有一定的工程实用价值。

In low permeability reservoir,common computational methods can＇t meet the demands of engineer ing for the complex distribution of the fractures underground and many factors of influencing productivity calculation.Radial flow model was established to describe seepage law for composite media in the fractured well of the low permeability reservoirs considering starting pressure gradient and deformation coefficient.Variation laws of pressure and production rate can be acquired according to this model under the conditions of different formations and fracture parameters.The calculation results show that the production rate will decrease with increasing of deformation coefficient and with increasing of starting pressure gradient,and show increasing of the production rate with increasing of fracture half-length under the conditions of the same drawdown pressure.This mathematic model has certain practical engineering value for it can be applied to know the variation laws of pressure and production rate in the fractured wells with the deformed-media formation in the low permeability reservoir.