HEAT FLOW DENSITY DISTRIBUTION MAP OF THE FOUNDATION ROOF IN THE EASTERN PART OF THE TOMSK REGION

Abstract

The relevance of studying the unallocated subsoil fund of the east of the Tomsk region is determined by the prospects and underexplored right bank of the Ob River. The subsoil user does not want to take risks there, the same about the State. However, oil companies will be forced to develop the eastern regions when production at the oil fields on the left bank drops to a critical level of profitability. A number of promising areas for exploratory drilling have already been identified on the right bank. The main aim of the research of geologists and geophysicists in the oil industry in Western Siberia and in particular the Tomsk region is a significant increase in reserves and accordingly prevention decline in oil production. This is the aim of the present work. The objects of the study are hard-to-recover reserves which requires the solution of the scientific problem of theoretical and experimental study of thermodynamics and material composition of the Western Siberia Paleozoic. The key geodynamic parameter that determines geotemperatures and the time of its impact on the centers of hydrocarbon generation is the heat flow of the foundation roof. It serves as the basis for basin modeling in prospecting and exploration. The construction and general analysis of the heat flow density map of the foundation roof of the Tomsk region east were carried out for a joint study of the prospects for the oil and gas potential of the poorly studied Bakchar mezodepression and the areas of the preliminary forecast of the East Paidugin megadepression. Methods. The original software «TeploDialog» was used to perform the simulation. This software package implements specially formulated direct and inverse geothermal problems under sedimentation conditions. Determining the value of the heat flow density from the roof of the foundation is complicated by taking into account many processes occurring both in the bowels and on the surface of the Earth. Therefore, an integral approach was used in the calculations, allowing these processes to be taken into account with the help of conjugated structural-tectonic reconstructions. The initial data for the model are reservoir temperatures measured during well testing, as well as taken from temperature gradient diagrams. The values of the reflectivity of vitrinite and the thermophysical properties of rocks systematically replenish the database of the IPGG named after A.A. Trofimuk SB RAS by analytical studies under the supervision of A.N. Fomin and A.D. Duchkov. The result. The heat flow density map (in isolines through 2 mW/m2) from the base of the sedimentary section for the northeastern part of the Tomsk region was prepared on the basis of calculations of 59 parametric, reference and exploration wells. The heat flow values were obtained using a single well-tested method based on solving the inverse geothermal problem. In terms of setting the task of the completed scientific work, a certain part of the scientific problem of theoretical and experimental study of the upper part of the Paleozoic thermodynamics was solved. The resulting discrete distribution (by wells) and the map of heat flow values from the pre-Jurassic basement can serve as a base for correct basin modeling of the Bakchar study area and the poorly studied large area of the East Paidugin megadepression. This region is not promising in terms of the sedimentary cover taking into account the low values of the modern heat flow. However, the determination of the vitrinite reflectance index of the Paleozoic section can significantly expand the prospects for the oil and gas potential of the weathering crust and the upper horizons of the Paleozoic. Conclusions. A unified map of the heat flow density of the foundation roof of the Tomsk region constructed at the next stage on the territory of which three graben rifts: Koltogor-Urengoy, Ust-Tym and Chuzik, were developed, will be the important result. This fact is of particular interest and requires separate careful consideration.

Keywords

• increase in hydrocarbon reserves on the lands of the east of the tomsk region
• heat flow density map from the basement roof
• theoretical and experimental study of the paleozoic thermodynamics and material composition