ESTIMATION OF LAMINATED RESERVOIR PROPERTIES (A CASE STUDY/ TORTONIAN OIL RESERVOIR)

The lack of information for reservoir characterization has been a common problem nowadays due to the current economic limitations on companies' capital expenses. Therefore, the reservoir engineer has to fully exploit all available data and estimate the unavailable reservoir characteristics. For lack of core data, the porosity is usually used to estimate the permeability through classical correlations. However, predicting permeability from porosity only and using classical relationships becomes unreliable due to lithology and pore geometry effects. The objective of this study is to test the integration between Flow Zone Indicator (FZI), Artificial Neural Network (ANN), and Convergent Interpolation (CI) techniques to enhance the Tortonian reservoir description in the Gamma oil field using the data of one exploratory well and four appraisal wells. The reservoir description is done through 1) modeling the non-linear relationship between the Tortonian reservoir properties, 2) calculating the effective porosity after considering the effect of shale on well-log porosity measurements, 3) estimating the permeability of appraisal wells (uncored wells), and 4) creating a permeability map for the Tortonian oil reservoir. The results showed that three rock types present within the Tortonian reservoirs. The effective porosity and permeability logs were successfully estimated, and the comparison between the created permeability log and quality check logs (GR and porosity logs) reflected the high model quality. A permeability map has been created and showed a direct relationship with the porosity map, which validates the methodology. The reliability of the porosity/permeability relationship has increased up to 90% after using the integrated techniques presented in the study. The integration between FZI, ANN, and Convergent Interpolation techniques has successfully modeled the non-linear intercourse between the porosity and permeability of the Tortonian reservoir. The study enabled improving the complex reservoir description economically with the minimum capital budget and available data.