曲流点坝薄夹层构形对驱油效率及剩余油形成与分布的影响

陆相储层单砂体内的薄夹层是形成储层流体流动非均质的主要因素之一,单砂体内部薄夹层极薄、规模小、测井全部识别有一定困难,且位于层内。在油田开发初、中期作用不明显,而在高含水期、三采阶段,单砂体及其渗透率宏观分布已不能详尽揭示层内剩余油分布,层内薄夹层对注入剂驱油的影响及其重要性逐渐显现出来,与渗透率在储层内韵律性分布有同等重要的地位,也是储层精细表征的重要内容。以往只是着重从渗透率在储层内分布的不均衡的角度来研究储层中驱油效率问题,忽略了薄夹层的对储层驱油效率的影响。以大庆油田葡萄花油层组PⅠ2小层曲流河道砂体为例,对曲流河道砂体内部薄夹层构形对驱油效率及剩余油的形成与分布作了初步的分析和探讨。在排除开发因素差异的同井单砂体分析条件下,提出了“单砂体内部薄夹层空间构形 渗透率垂向序列 重力”三因素共同控制剩余油分布、驱油效率多段垂向序列模式。

Effects of Thin Meander Dot Dam Interbeds on Flushing Efficiency and on Formation and Distribution of Residual Oil

hin interbeds in single sand bodies in continental reservoirs are an important factor for the anisotropy of fluid flows in the reservoirs.The interbeds in the single sand bodies are very thin,on small scales and hard to be recognized entirely by logging.The actions of the interbeds are not apparent during the period of oil field exploitation,while at the high water content period and the third picking phase,influences of the thin interbeds on impregnant edge-water encroachment become more and more apparent since the single sand bodies and microscopic distribution of the permeability cannot reveal the distribution of residual oil in the reservoirs.Thus,the interbeds can be considered as important as rhythmic distribution of permeability within the reservoirs and also the significant content of reservoir details.