各向异性油藏水平井线性井网渗流场分析

Study on Seepage Field of Horizontal Linear Well Pattern in Anisotropic Reservoirs

为了直观地反映各向异性油藏水平井线性井网地层压力分布及流体运动轨迹的特点,建立了各向异性油藏水平井不稳定渗流的数学模型,利用源汇理论、Newman乘积法及压降叠加原理获得了各向异性油藏水平井井网不稳定渗流地层压力公式,给出了流线生成方法,研究了水平井线性井网渗流场分布规律。结果表明:储层各向异性和生产时间对水平井线性井网渗流场影响较大。在不同的各向异性强度下存在着不同的最佳井排距,使水驱波及效率和水平井的产能达到最大。生产时间越长,则压力传播范围越广,采出程度越高。利用本文方法产生的流场图能够为各向异性油藏水平井开发井网设计、剩余油分析及注入方案的优化提供科学依据。

In order to visually reflect the characteristics of pressure distribution and flowing tracks of reservoir fluid in anisotropic reservoirs, the unsteady-stated flow mathematical model of horizontal wells in anisotropic reservoirs was established. By means of the source-sink theory, Newman＇s product method and pressure drop superposition principle, the unsteady-stated flow pressure distribution equation of horizontal well pattern was obtained, the calculation method of seepage field streamline was presented, and the distribution law for seepage field was studied. It is shown that the seepage field of horizontal well pattern is sensitive to the reservoir anisotropic and the production time. There is a reasonable well spacing and row spacing under a given degree of anisotropy, which can maximize the effect of displacement and the productivity of horizontal well. The longer the production time is, the bigger the pressure propagation area is, and the higher the degree of reserve recovery is. The seepage field plots generated by this method can provide a scientific basis for the design of horizontal development well pattern, analysis of remain oil and optimization of injection strategy in anisotropic reservoirs.