矢量井网改善平面非均质油藏水驱开发效果研究

Research on water flooding effect improved by vectorial well arrangement for reservoirs with permeability heterogeneity in plane

平面非均质是河流相沉积的重要特征。如果采用常规等井距五点井网开发该类油藏,往往会导致注入水在高渗透方向的突进,造成部分生产井见水时间早,含水上升快,而渗透率较低方向上的生产井注水受效不明显,当井组内的综合含水达到98%时,注入水在该方向上还没有突破,即注水驱替往往不均衡,开发效果差。在渗流力学基础上,推导了平面非均质油藏矢量井网的井距设计公式。根据矢量井网的井距设计公式,建造了物理模型,开展了水驱油对比试验研究,检验了用矢量井网开发平面非均质油藏的有效性。试验结果表明:矢量井网能增大平面非均质油藏的波及系数,提高注入水的利用率,大大改善油藏开发效果。

Permeability heterogeneity in plane is an important characteristic of fluvial facies formation. If it is developed using conventional five-spot well arrangement with equal-well-space, the injection water often fingers along high permeability strip quickly, which results in early water-breakthrough and quick water-cut increase for parts of the wells, while wells in relatively low permeability strips can not be flooded effectively; water does not break through as total water-cut for a well group reaches 98 %, That is, the reservoir can not be flooded in equilibrium, and the developing result is not good. The design formula for well space of vectorial well arrangement for permeability heterogeneity in plane is derived based on porous flow theory. According to the well space formula of vectorial well arrangement, the physical models are made to carry out the contrastive water flooding experiments which are used to check the validity of vectorial well arrangement, The results indicate that the vectorial well arrangement can improve the plane sweep factor for reservoirs with permeability heterogeneity, and raise the efficiency of injection water; moreover, it could improve the developing effect greatly.