特低渗透砂岩油藏剩余油分布的主控因素及有利区块评价

根据特低渗透砂岩油藏储量动用不均衡的特点,提出了采用动态生产指标来对生产区块进行标定和分类,并通过动、静态相结合的方法分析特低渗透油藏剩余油的主要控制因素,在此基础上,再利用模糊数学评判的方法进行定量分析,指出有利的挖潜区块。对胜利油区五号桩油田桩74块特低渗透砂岩油藏的动、静态特征分析表明,该油藏沉积微相、微型构造及储层非均质性是特低渗透油藏剩余油分布的主要控制因素。其中,沉积微相的控制作用最强,微型构造次之,非均质性控制作用最弱。在沉积微相中,中扇亚相的辫状水道微相是最有利的微相带,中扇水道侧缘微相具有一定的可采储量,但由于相带狭窄不利于后期调整加密;朵叶体微相的井网稀,具有一定的生产开发潜力;顶凸底凸型和顶底均为鼻状凸起型微构造组合模式,水淹程度弱,既是高产区也是剩余油富集区。渗透率变异系数为0.3~0.9的区域,剩余油相对富集。最后以5砂组为例,采用模糊数学方法并结合剩余油控制因素分析结果进行了剩余油定量评判,指出了有利区域,经检验取得了良好的效果。

Key factors of remaining oil distribution of the lowest permeable sandstone reservoir and favorable area evaluation

According to characters of reserves' employ in the lowest permeable sandstone reservoir,the dynamic production target was used to classify the producing tract and the key factors of remaining oil distribution through combination of dynamic and static behaviors were analyzed.On the basis of the study,the favorable district by the quantitative analysis was determined by the fuzzy set theory.Through the analysis of dynamic and static behaviors about Zhuang 74 fault block in Wuhaozhuang Oilfield,sedimentary microfacies,microstructure and heterogeneity are the key factors of remaining oil distribution of the lowest permeable sandstone reservoir.The sedimentary microfacies takes on the strongest effect.Microstructure is moderate,and heterogeneity is small.In middle fan,the braided channel is the best microfacies,and channel edge is too narrow to make hole.And lobe is the potential microfacies.Two-type microstructure mode of double convexity mode and double nose mode,and the coefficient of permeability variation,which is from 0.3 to 0.9,are taken account into tapping remaining oil potentials.Five sand members were taken for example to evaluate quantitatively and the favorable area was indicated using the fuzzy set theory and the analysis of the key factors of remaining oil distribution.Through back-to-back test,the remaining oil in the lowest permeable reservoir was studied by the method.The results show that it is practical and the good effect is provided.