各向异性油藏中五点井网的变形作用

针对各向异性油藏中水驱开发的研究主要集中于各向异性方向垂直或平行于井网单元中任意两口井的连线方向等特殊的情形，而对于其他布井方向的研究相对缺乏的这种情况，采用坐标变换方法将各向异性油藏转化为各向同性油藏，然后利用流线方法计算正五点井网的开发指标，分析了各向异性程度和方向对水驱开发效果的影响。结果表明，在各向异性油藏中，各向异性程度越大，井网的变形程度也越大；当井网单元中任意两口井的连线与渗透率主轴方向既不平行又不垂直时，井网开发效果对各向异性程度的变化反应十分敏感，井网单元可能会发生的破坏和重组现象，这种破坏和重组现象是各向异性方向和大小两者共同作用的结果，从而造成了井网开发效果的不确定性。为了有效避免可能发生的井网的破坏和重组现象，布井时最好选择注水井生产井方向或者注水井注水井方向平行或者垂直于渗透率主轴方向。

Deformation of Five-spot Well Patterns for Anisotropic Oil Reservoir

Existing researches of anisotropic oil reservoir mainly focus on two special types of well patterns in which the injectorto-producer or producer-to-producer direction is parallel to the principal permeability direction, and the studies concentrating on other types of well patterns are rare. The primary reason is that other types of well patterns might increase the uncertainty of development effect. Based on coordinate transformation method, the real anisotropic oil reservoir can be converted into a equivalent isotropic oil reservoir, and the flow field and development indexes of well pattern can be also calculated, and on this basis, the impact of the degree and direction of anisotropy on the development effect can be analyzed. Research results indicate that the existence of directional permeability can lead to deformation, even destruction and reconstruction, of original well pattern flooding units, when the principal permeability direction is neither parallel nor perpendicular to the injector-producer direction and injector-injector direction. The destruction and reconstruction of well patterns is a consequence of the anisotropic degree and the relative angel between anisotropic direction and well line direction, thereby resulting in the uncertainty of well patterns development effect. In anisotropic reservoir, the degree of anisotropy is greater, the deformation effect of well patterns is severer, and the development effect of well pattern is more sensitive to the change of angle between maximum principal permeability direction and well line direction. To avoid the occurrence of destruction and reconstruction effectively, the best choice for pattern configuration is making sure that the injector-to-producer or producer-to-producer direction is parallel to the principal permeability direction.