| Title | Geothermal Regime and Deep Temperatures of the Siberian Platform |
|---|---|
| Authors | Raisa DOROFEEVA |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | heat flow, deep temperature, thermal conductivity, geothermal gradient, boreholes, mapping of sediment layers, oil and gas deposition |
| Abstract | Based on well-understood geothermal regime of the southern East Siberia (about 200 heat-flow measurement points), the present paper deals with the study of deep temperatures of the southern Siberian platform (more than 70 boreholes, average heat flow 38+-4 mW/m2) and thermophysical properties of core samples mostly representing the Vendian terrigenous deposits and Riphean magmatic and metamorphic basement rocks. The basement rocks, according to their thermal properties, are subdivided into two groups with thermal conductivity coefficients 3 and 2 W/mK. Higher coefficients indicate the presence of carbonate-halogen admixtures. Studies have been made of the thermograms of the boreholes and temperatures at the bottom and top of the Motskaya suite, lower Cambrian (ˆ mt3). The depths of the boreholes vary from 1300 to 6000 m, and the borehole temperature attains a value as high as 70 îC. Rather intense heat transfer (45+-6 mW/m2) is observed in the anticlinal domes and salt-dome crests, and low heat flow rate is typical of marginal uplifts. Geothermal peculiarity is also closely related to hydrodynamic features of the area where underground water seepage flow penetrates to depths of 3-5 km and diffusion flow prevails in deeper crust. Anomalous formation conditions exert influence on dynamics of hydrocarbon accumulation, which in turn is also predetermined by geothermal conditions. |