Известия Томского политехнического университета: Инжиниринг георесурсов (Jan 2018)
Zoning of neocomian reservoirs of the Koltogor mezodepression and its fraiming structures by generation and accumulation density of Bazhenov oil
Abstract
The relevance of the research is caused by the need to reproduce and expand the resource foundation of oilfields in Tomsk region. The aim of the research is to identify the priority zones for exploration and development of Neocomian oil-gas complex in the territory of Koltogor mezodepression and its fraiming structure. The targets of the research are oil source Bazhenov formation, Achimov and Shelf neocomian reservoir. Research methods: geomapping of reservoirs thickness; computer paleotectonic and paleotemperature reconstruction of the sedimentary cover in sections of deep wells including the deposits of source rocks; mapping of intensive generation centers of Bazhenov oil by geotemperature criteria; integral estimation of density distribution of generated oil; complex estimation and analysis of density distribution of accumulated oil in Achimov and Shelf Neocomian reservoirs. Research results. The paper introduces the volume-area characteristic of the Achimov and Shelf neocomian reservoirs. The authors have generated the maps of summary thicknesses of eight cyclites of Achimov and six cyclites of Shelf sediments. The thermal history of the Bazhenov formation in the sections of 48 deep wells was reconstructed for 17 key moments of geological time. The centers of Bazhenov oil generation were identified. The authors formed the map of generated oil density distribution, the maps of accumulated oil density distribution and performed zoning of the Achimov and Shelf reservoirs. The northeastern part of the Kaimysov arch and its articulation with the Cheremshanka and Ledyansk mesossaddles, with the Koltogor mezodepression and territory of articulation of the Traygorod mezowell with the Koltogor mezodepression were determined as the prospective zones for exploration of the Achimov reservoir. The territory of articulation of the Cheremshanka mesossaddle and the Koltogor mezodepression, territory of the Traygorod mezowell were determined as prospective zones for exploration of the Shelf reservoir. Conclusions. The comparison of direct sign of oil and forecasted zones of high prospects of Clinoform and Shelf sediments showed the certain coherence - 66 % for the Achimov reservoir and 62 % for the Shelf reservoir. The zoning of the reservoirs determined the priority areas for exploration in the Lower Cretaceous sediments - the northeastern part of the Kaimysov arch and its articulation with the Cheremshanka and Ledyansk mesossaddles, with the Koltogor mezodepression and territory of the Traygorod mezowell. Integration of geothermy data was argumentedly demonstrated for solving oil exploration problems.
