Paradigm-shifting geological model of hauterivian-barremian-aptian reservoirs: example of Vatyogansky field

Maintaining oil production levels in West Siberian mature fields is impossible without geological models representing the structure of natural reservoirs and oil pools to the fullest extent possible. Modern modelling is carried out using multifunctional software tools that allow considering the full extent of historically accumulated geological data. However, the most important factor of the goodness of model fit to the object being modelled is the methodological basis, namely: choice of the proper geological concept of natural reservoir structure behind the modelling. Failure to take into account or insufficient elaboration of a concept result in simplified understanding of geological structure. Hidden behind the false understanding, such a model may exist for years and accumulate numerous mismatches and assumptions; in the course of time this can cause crisis of confidence in the geological framework. For subsoil users, this threatens higher economic costs, which are especially critical in the final stages of field development. By the example of the Hauterivian-Barremian-Aptian productive reservoirs of the AB group formations in the unique Vatyogansky field, the authors demonstrate the possibility of revising historical geological models. Rethinking of the conceptual framework included reservoir genesis that was a key to understanding of formation of the complicated reservoir system. Picking carried out on the basis of the new concept takes into account the genetic features of the rocks and demonstrates the numerous reservoir confluence “windows”. The new model allowed explaining the numerous legacy assumptions and presenting all the actual complexity of geological structure