Известия Томского политехнического университета: Инжиниринг георесурсов (May 2019)
Development of the effective technique for assessing hydrocarbon resources applying the comparative-historical method and geothermal as a new method of exploration geophysics
Abstract
The relevance of the research is caused by the need to improve a technique of assessing the hydrocarbon resources by the volume and genetic method based on paleoreconstruction of geotemperature mode of petromaternal deposits. The main aim of the research is to assess the influence of the century course of temperatures on Earth surface on geothermal mode of petromaternal deposits of the southeast of Western Siberia, on the extent of realization of their generative potential. Objects of researches: average annual temperatures in the Mesozoic and the Cenozoic of the southern paleoclimatic zone of Western Siberia, Bazhenov deposits of the Mesozoic and Cenozoic section opened with deep wells at latitudes of Tomsk and Novosibirsk areas. Methods of researches: the analytical report of reconstruction of the century course of temperatures on a day surface in the Mesozoic Cenozoic executed with application of an actualistic method; a method of paleotemperature modeling for a quantitative assessment of influence of a paleoclimate factor on the geothermal mode of maternal deposits and intensity of generation of hydrocarbons. Research results. The authors have synthesized the geographical and geochronological of the data on the century course of temperatures on Earth surface of the southeast of Western Siberia published in the period of 1974-2011. The data were obtained by a number of authors on the basis of the comparative-historical analysis of sedimentary thicknesses lithology, flora areas, and materials of isotope and magnesia thermometry. For the southern paleoclimatic zone (Tomsk, Novosibirsk and Omsk areas) the «local» century course of temperatures on a terrestrial surface, since the Jurassic time, was constructed. By geotemperature criterion the authors allocated the centers of intensive generation the Bazhenov oil by paleotemperature modeling of sedimentary cover, including petromaternal deposits; calculated and the analyzed the distribution of oil resources relative density. The quantitative assessment of paleoclimate influence on geothermal mode and extent of realization of generative capacity of the Bazhenov suite, the hydrocarbons of petroleum potential complexes of Tomsk and Novosibirsk oil fields forming deposits was received. It is shown that without considering paleoclimate it is impossible to restore adequately thermal history of maternal deposits that may underestimate to 2 times or more the value of the estimated resources by a volume and genetic method. Use of the "local" century course of temperatures on the Earth surface increases the efficiency of technology for defining the expected resources, allows considering more correctly the history of the main phase of oil formation, both without overestimating/underestimating (to 30-40 %) the settlement resources. The paper demonstrates the continuity and scientific and practical importance of combination of a comparative-historical (actualistic) method of classical geology and a new method of exploration geophysics - geothermics - when solving the problems of assessing hydrocarbon resources.
