Abstract
The method for quantitative prediction of the reservoir connectivity is given for one of the oilfields of Tomsk area. The studied upper Jurassic reservoir was formed in coastal environment and penetrated with a small number of wells.
The volume of recoverable oil is depend on chosen method for lithology or N/G modelling. The calculations, which were done on geology and simulation models, showed that recoveryg factor changes can reach 35% and related to reservoir connectivity. The Tomsk area reservoirs geomodels, which have production history and total oil production, is higher than 60% of recoverable oil reserves, were studied in order to develop method to predict connectivity coefficient of reservoirs. The relations between reservoir heterogeneity and sedimentology features and log data were found. It allowed making prediction for connectivity coefficient value for case study reservoir.
In addition, production data of two wells of case study reservoir were considered. Analysis of wells from other Tomsk reservoirs with the same completion type shows that connectivity value is related with well production rate drop factor. This regression allows predicting desired connectivity coefficient for case study reservoir in order to provide appropriate heterogeneity to match model with production history data.
Finally, the modeling method with continuous N/G property was chosen for geomodel. This is the only method, which allows achieving heterogeneity level that corresponds to sedimentary environments, log features and production history data. As a result, more accurate geomodel was created which has lower uncertainty lever in prediction of reservoir properties in non-drilled part of the reservoir.
