Borehole Temperature Logging and Characteristics of Subsurface Temperature in the Sichuan Basin

TLDR

The study presents contour maps of geothermal gradient and heat flow in the Sichuan Basin, integrating new temperature‑logging data with existing datasets. The analysis reveals nine high‑quality terrestrial heat flows, a lithology‑controlled thermal‑conductivity stratigraphic column, an average geothermal gradient of 22.8 °C/km and heat flow of 53.2 mW/m², with higher values in the southwestern and central basin and lower values in the north, reflecting tectonic influences.

Abstract

Abstract Based on temperature logging of 9 boreholes and thermal conductivity measurement of 297 samples in Sichuan basin, 9 terrestrial heat‐flows of high quality are reported and thermal conductivity stratigraphic column is suggested as well. The contour maps of geothermal gradient and heat flow are presented after combining with previously available data. The variation of thermal conductivity of sedimentary rocks in Sichuan basin is mainly controlled by the lithology, rather than the current burial depths. At present, the geothermal gradient ranges from 17.7 to 33.3 °C/km with an average value of 22.8 °C/km in the basin, and the heat flow ranges from 35.4 to 68.8 mW/m 2 with an average of 53.2 mW/m 2 , which are typical of cratonic basins with medium‐low heat flows. In regard to the areal distribution of heat flows, they are relatively higher in the southwestern and central part and lower in the northern part of the Sichuan basin. The heat flows are apparently dependent upon tectonic settings of the basement.