Известия Томского политехнического университета: Инжиниринг георесурсов (Aug 2017)
Tectonic-sedimentation interpretation of the geothermics data when identifying and assessing the late eocene erosion on the arctic hydrocarbon fields (Yamal peninsula)
Abstract
Relevance. The scheme and criteria of use of the measured and modelled geo-temperatures is developed for studying of teсtonic-sedimentation history of settling ponds of the Arctic region of Western Siberia - priority subject of the new strategy of development for asource of raw materials of hydrocarbons of the Russian Federation. The aim of the research is to develop and approve a technique of assessment of the Late Eocene time erosion of the Arctic districts of the West Siberian oil-and-gas province on the basis of model operation of the geothermic mode of the Bazhenov petromaternal deposits, on the example of the Arctic, Sredne-Yamalsky and Rostovtsevsky fields. Object of researches: tectonic-sedimentation history of a Cenozoic and Mesozoic section, the paleo thermic mode of the Bazhenov deposits opened with deep wells on the Arctic, Sredne-Yamalsky and Rostovtsevsky squares (Yamal Peninsula).A special method of the research is based on: 1) the paleo-temperature modeling considering the parameters of tectonic-sedimenta-tion history, measured rock temperatures and paleo-temperatures determined by the reflection power of vitrinite; 2) diversity of paleo-tectonic and the paleo-temperature reconstruction and on the analysis of variability of results; 3) assessment of results compliance withthe optimality criteria of the geophysics inverse problem solution; 4) coherence of the designed values of heat flux density with the experimental data; 5) coherence of the calculated centers of hydrocarbon oscillation with the oil-and-gas content of a subsoil establishedby geological exploration. Research results. The implemented variety of scenarios for tectono-sedimentary history and reconstructions of geothermal regime of the Bazhenov formation has revealed and given the quantification of breaks in sedimentation and denudate in еру Late Eocene time on hydrocarbon deposits of Yamal. It was ascertained that engaging the data of vitrinite reflectance justify the existence of denudations and defines the possibility of assessing the scales of denudations. The scenario of geological development history considering the erosive processes gives the «richest» thermal history of maternal deposits, provides the greatest calculated density of resources of the generated oil. Application of the developed scheme and criteria of identifying the breaks of sedimentation and denudation by a geothermal method, in complex with geological methods and seismic exploration, significantly increases reliability of knowledge of the history of geological development of regions in Western Siberia.
