Известия Томского политехнического университета: Инжиниринг георесурсов (Mar 2018)
Reconstructions of geothermal mode of the petromaternal Kiterbutsk suite of the Arctic region in Western Siberia taking into account the influence of paleoclimate
Abstract
The relevance. The Arctic regions of Western Siberia became a priority area of research and exploration. They have the unique paleoclimate features, the inversion sedimentation in Paleogene-Neogene and the considerable variations of petromaternal deposit characteristics. This causes the necessity to improve schemes and determine parameters of quantitative assessment of hydrocarbon resources by volume-genetic method based on geotemperature mode paleoreconstructions of petromaternal deposit. The main aim of the research is to identify and estimate the impact of paleoclimate factors - temperature secular variation of the Earth surface and Neo-Pleistocene permafrost thicknesses, glacial covers - on the settlement geothermal mode of the petromaternal Early Jurassic Kiterbutsk suite. Object: Kiterbutsk deposit of Mesozoic and Cenozoic sections opened by deep wells on areas of Maloyamalskoye, Arkticheskoye and Bovanenkovskoye fields (Yamal peninsula). Method of the research is based on the original computer paleotemperature modeling considering the parameters of sedimentation history and the history of thermophysical properties of sedimentary thickness, including permafrost rocks and glaciers, and not demanding aprioristic data on the origin and quantity of deep heat flow. Research results of the representative Mesozoic-Cenozoic sections of the fields located in southern, central and northern regions of Yamal peninsula, allowed drawing the conclusions and making recommendations. Consideration of the paleoclimate causes the most accurate thermal history of maternal deposits, increase in 5-18 C the calculated paleotemperature maximum in the history of Kiterbutsk deposit. The authors recommend to apply the unique for the area «arctic» secular temperature variation and take into account the dynamics of permafrost Neo-Pleistocene strata about of 300-600 meters in determining the kiterbutsk petroleum resources by volumetric-genetic method on the territory of Arctic region. The authors noted insufficient influence of glacial cover on thermal mode reconstruction. When neglecting the permafrost and paleoclimate secular temperatures variation the calculated hydrocarbon resources may be undervalued from 30 percent to triple. The reliability of conclusions is confidently controlled by the geophysical «residual» criterion, comparing with experimental heat flow data of the studied area and consistency with data of drilling and testing wells.
