岩心循环饱和油水驱替实验剩余油成因解释

Interpretation about Remaining Oil Causes in The Rock with Oil-Water Cyclically Saturated

目前对油藏剩余油成因的解释主要为部分储层单元未被驱替到或原油未能从驱替到的储层单元内被驱替出,然而实际油藏严重水驱区域仍含有大量剩余油的事实表明,传统分析不能充分解释剩余油的存在。通过从油藏某一单元驱替-再次饱和油-再次驱替角度对剩余油进行了解释,提出了“动态剩余油”和“动态束缚水”这一概念,并与低渗储层临界水饱和度进行有效区分。室内单一岩心循环原油饱和、驱替的实验表明,再次饱和油时原油饱和度降低可达到50%,再次驱替时剩余油饱和度增加也可达到20%,说明了实际油藏动态剩余油和动态束缚水存在的可能性;虽然不能科学地用于实验性能对比,单一岩心多次驱替仍被证明具有一定的实验价值。

At present,the mainly explanation for remaining oil causes in reservoir is that part units of the reservoir are not flooded and crude oil in part units are not fully displaced out,however the fact of serious water flooding area in actual reservoir still containing a lot of remaining oil show that the traditional analysis can not sufficiently explain the presence of remaining oil.From the point of reservoir unit going through displaced-again oil saturated-again displaced process,a new interpretation of remaining oil is given in this paper,concepts of"dynamic remaining oil"and"dynamic bound water"are put forward and distinguished from"critical water saturation"existed in low permeability reservoir.Indoor single core multiple oil saturating-flooding experiment shows that the again-oil saturated core has a lower oil saturation of maximum 50%,while again-displaced core has a higher remaining oil saturation of maximum 20%,compared with the initial oil saturating or flooding results.It indicates that the actual reservoir has a certain possibility of existing"dynamic remaining oil"and"dynamic bound water".In addition,single core multiple displacement experiment is proved of certain research value,though it can't be used for scientific performance comparison.