Carbonate reservoirs usually demonstrate considerable structural complexity and their high heterogeneity makes it difficult to predict their quality. Quite often productivity levels obtained in wells located close to each other and drilled to carbonate reservoirs differ from each other by a factor of ten or much more. Another issue is related to interpretation of log data in carbonate reservoirs: not always logs are sufficient to identify reservoirs and non-reservoirs and determine how much any component of the reservoir (fractures, cavities and matrix) contributes to the reservoir's effective capacity. High variety of poro-perm properties of carbonate reservoirs imply that geology and simulation modeling of hydrocarbon fields and making any forecasts for them bring about considerable difficulties and make it inevitable to use specific approaches to modeling process. Using as a case study one of the least clear fields by their geology in East Siberia, namely the Yurubcheno-Tokhomskoye field, the article describes an integrated approach to determining the reservoir's conceptual model and creating geological and simulation models.