Identifying productive zones of the Sarvak formation by integrating outputs of different classification methods

Abstract

Sarvak formation is the second major carbonate reservoir in Iran. There are several geological, petrophysical and geophysical investigations which have been carried out on this important reservoir. In this work, Sarvak is studied to find productive zones. At first, four different methods were used to identify producing intervals from well log data and well test results. Then, final zoning is generated by integrating outputs of these four methods. One of them is the conventional cutoff based method; the other three methods are based on flow equation, Bayesian and fuzzy theories. Thereafter, by considering the classification correctness rate of each classifier in each well and technique of majority voting, a unique zoning for Sarvak formation is presented. Based on the final zoning, the whole Sarvak interval is divided into seven zones. Three of them are classified as oil producing zones, two of them cannot be classified as conventionally producing zones, and the remaining two are water producing. Zone number 2 not only has the highest production rate, but also is the most homogeneous zone among the productive zones. The novelty of this research is using well test results in defining productive classes, which improves the certainty of classification in comparison with previous works that were based on core analysis and log data.

Net pay determination by Dempster rule of combination: Case study on Iranian offshore oil fields

“…Conventional cut-off-based methods provides a crisp (0/1) output (Masoudi et al, 2012a;Masoudi et al, 2012b;Masoudi et al, 2012c;Masoudi et al, 2011;Worthington, 2010).Due to reports of Iranian Offshore Oil Company (IOOC), kaolinite is dominant shale mineral in Mishrif reservoir of "C" oil field; furthermore, kaolinite-porosity plot is produced in each well, in order to distinguish different reservoir facies. Then, borders of each reservoir facies is interpreted as cut-off value of porosity or kaolinite.…”

“…Case study of Sarvak Formation, a carbonate reservoir (Masoudi et al, 2012a) Bayesian classifier/ Shale volume, porosity, water saturation and well test Case study of Sarvak Formation, a carbonate reservoir (Masoudi et al, 2012c) Fuzzy fusion/ LLD, LLD:LLS and well test Case study of Sarvak Formation, a carbonate reservoir (Masoudi et al, 2012b) Comparing methods of cut-off, diffusivity, Bayesian and Fuzzy…”

Geomechanical model and wellbore stability analysis utilizing acoustic impedance and reflection coefficient in a carbonate reservoir

“…On this plot, evaporate minerals, shale, Fig. 2 The location of Dezful embayment in Zagros Basin of Iran (Masoudi et al 2012) Fig. 3 Lithology/porosity crossplot, a density versus neutron and b density versus sonic and the gas impact can be seen.…”

Gamma-clustering sequence stratigraphy, case study of the carbonate Sarvak Formation, Southwest Iran

“…During the Early Cretaceous, an epeiric carbonate platform developed throughout the Zagros Basin [30]. [50][51][52] Development of the carbonate platform to intra-shelf basin along with reduction in siliciclastic contents resulted in deposition of carbonate sediments of the Sarvak Formation. In some provinces, e.g., Ilam and Fars, a Cenomanian unconformity separates the Sarvak Formation from the overlaying Ilam Formation (Fig.…”