Lithological features of coal-overlying accumulations of Upper Vasiugan formation of Kazan oil-gas-condensate field

The study of secondary transformations of accumulation has to be an integral component of modern lithological study because it allows understanding all the features of stages of processes that form accumulation and transform sedimetary rocks. This is essential in prediction of areas with better reservoir properties. In order to find features of reservoir rocks and its influence on reservoir properties the author conducted a detailed lithological study of accumulation of coal-overlying set of Upper Vasiugan formation of Kazan field. In terms of regional tectonics the field is located in central part of Kazan dome dedicated to local upheaval that is located on the east part of Niurol depression. As an object to study it was decided to choose deposits of coal-overlying set of Upper Vasiugan formation which cross-section includes sand layers and . This paper presents results of the study of composition of rock-forming and cementing matter of productive layers and of Kazan oil-gas-condensate field (Tomsk region). Studies showed that nature of reservoir properties of silty-sand rocks are mainly determined not only by sedimentation conditions, but nature of post-sedimentary changes as well. During the study of rock thin sections diagenetic and katagenetic indicators of lithogenesis are found. In order to determine causes of irregular porosity and permeability distribution along a thin section dependency of these properties on both primary (sedimentation) and secondary (post-sedimentation) factors were found. To find the answer for this challenge the author determined pair correlation coefficients and built diagrams. As a result of the study parameters that improve and deteriorate reservoir properties of sandstones of Kazan deposits were identified

Geochemistry of impurity elements of Upper Jurassic deposits of Kazan fields group

Both sandstones and fine-grain clastic debris have integrated information about factors controlling its formation processes. This information is contained in litho-geochemical characteristics. Obtained information complement and specify results of lithologic research carried by conventional methods. The subject of the research are deposits of Kazan oil-gas-condensate field and Boltnoe oil field that are located in Parabel territory of Tomsk region. In terms of structure Kazan and Bolotnoe fields are dedicated to dome uplifts of the same names and located in south-east part of Niurolsk depression within the border of 2nd class positive structure Kalgachskii Mesozoic uplift. Geological structure of the field is formed by metamorphosed basement rocks and siliciclastic deposits of different composition of Mesozoic-Cenozoic platform mantle. Productive deposits of Upper Jurassic are the field of interest. Upper series of Jurassic deposits on studied area is presented by Vasiugan, Georgiev and Bazhenov formations that are drilled and characterized in details by core. Obtained data proved the rule of change of rare earth elements composition between different conditions of marginal-marine line and showed tendency of some elements to grow and decrease of other going out from margin. Sedimentary rocks of south-east part of Niurolsk depression are differentiated in geochemical and mineral-petrographical compositions. Both are presented by wide range of variety. With use of obtained geochemical data and evaluation of indicators determined environments of sedimentation are proved. Fundamental parameters of sedimentary rocks such as composition and proximity of a source, salinity and paleoclimates are determined