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

Key words:  Wuhaozhuang Oilfield  lowest permeable reservoir  sedimentary microfacies  microstructure  fuzzy set theory  remaining oil distribution  key factors

Abstract:

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 Wuha-ozhuang 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.