低流度油藏渗流影响因素实验研究

EXPERIMENTAL STUDY OF FILTRATION AFFECTING FACTOR IN LOW MOBILITY RESERVOIR

随着油田开发进入中后期,低流度油藏将成为今后维持稳产乃至增产的主要目标,但低流度油藏开发受渗流的影响较大。对取自我国东部某油田低流度油藏岩心进行了岩心恒速压汞、应力敏感性及裂缝闭合实验,实验表明研究区岩心在微观孔喉上有较大差异。由束缚水饱和度、岩心渗透率的不同会造成岩样随有效压力的变化而引起应力敏感伤害的差异。裂缝会随着地层压力的降低发生闭合,表现出极强的应力敏感性,使得渗透率急剧降低。这些因素都会对低流度油藏渗流产生影响从而影响采出程度以及最终的采收率。通过研究低流度油藏渗流的影响因素,为低流度油藏开发采用合理的工艺措施提供了指导依据。

Many oilfields in China are in the middle or late stage of exploitation,so low mobility reservoir will become the main target of exploitation.Exploitation of low mobility reservoir is great influenced by percolation,the research of low mobility reservoir percolation can provide relative basis for it.Experiments of Automated system for pore examination,stress sensitivity and fracture closure were done.The results showed that there are great differences in micro-porosity and micro-throat in the research area.Because of the difference of bound water saturation and permeability,stress sensitivity change along with the change of active pressure.Fracture close along with decline of pressure,which cause permeability sharply degrade.Those factors can affect the filtration of low mobility reservoir,which can affect recovery percent and total recovery.