The Vankor oilfield in Eastern Siberia is characterized by multiple layers of varying types of hydrocarbons, including oils ranging in viscosity from less than 1 cp to over 20 cp, the Russian regulatory cut-off for heavy oil. It is important for every reservoir penetration to determine the type of oil encountered and also to make any possible inferences about reservoir connectivity. Wireline formation testers equipped with downhole fluid analysis (DFA) sensors acquiring color and gas-oil ratio data (GOR) are used to determine the hydrocarbon type and fluid property gradients. Then, using the emerging technology of asphaltene gradient modeling and prediction for heavier oils, we are able to help support conclusions of reservoir connectivity.
In this paper we present datasets from wells where we determine the fluid type from DFA data. Additionally, we incorporate color with pressure gradient data to help build reservoir models that predict reservoir connectivity and compartmentalization.