注水开发油藏时,储层各小层之间的物性差异会引起水驱前缘的不均匀推进,即形成指进现象。储层渗透率差异、油水黏度差异和储层倾角等都会影响指进的程度。储层渗透率差异和油水黏度差异的增加会加剧孔道内油水流动速度的差异,进而加剧指进现象;而储层倾角的增大则使水驱前缘的含水饱和度增大,移动距离变小,有利于削弱指进现象。在油藏高含水阶段,指进现象十分明显,会严重影响油田水驱的开发效果。通过对指进现象的研究,分析形成指进现象的原因,进而利用指进现象调整油田开发的注采结构模式,为改善高含水期水驱油藏的开发效果提供理论指导。通过实验,进行注采结构调整时,采收率提高2.97%,说明利用指进现象调整油田开发的注采结构模式具有可行性。
Differences in reservoir properties lead to uneven water front when water flooding, which is called fingering. Such parameters as permeability heterogeneity, water/oil viscosity difference and reservoir inclination will affect the intensity of fingering. Increase in permeability heterogeneity and viscosity difference in different pore structures, resulting in graver fingering, while the increase of reservoir inclination will increase saturation of the wa- ter front and help to weaken fingering phenomenon. Fingering is more serious in reservoirs of high water cut and drastically affects final recovery. In this essay, the causes of fingering are studied in order to analyze injection ad- justment, thus providing theoretical guides for improving water flooding recovery. The result of physical experiments shows that by applying fingering theory into injection adjustment, recovery is enhanced by 2.97% , which confirms the feasibility of adjusting injection by considering fingering phenomenon.