| Popis: |
Summary The report deals with the analysis of Turonian lithofacies structure using the case study of one of the fields of West Siberia. In West Siberia, the Turonian is a prospective target owing to its gas content. At the same time, this type of sediments falls under hard-to-recover reserves. The major challenge in the study and development of such accumulations are their low reservoir properties due to high clay content and near-surface conditions. Lithofacies analysis was based on core studies (of 5 wells). In general, the reservoir is composed of siltstones with various content of clay and sand fractions, intensively bioturbated, with frequently occurring marine fossils. Rock typing was based on core laboratory investigations. The main criteria for classifying the rocks into lithotypes which affect petrophysical properties are the grain size distribution (sand material admixture) and clay cement content. A cyclic sequence has been recognized that consists of four cycles. Each cycle is characterized by regressive nature. It has been found that the cycles in the northern and southern parts of the field have different thickness, which is attributed to several sedimentary material source areas. |
