Frontiers in Earth Science (Mar 2022)
Distribution Characteristics of the Deep Geothermal Field in the Sichuan Basin and its Main Controlling Factors
Abstract
Geothermal energy and petroleum are two resources that coexist in sedimentary basins, and both of them are closely related to temperature. Based on the surface heat flow and the rock thermophysical properties, the deep geothermal field was calculated, then temperature distribution characteristics and the primary influencing factors on the geothermal state were discussed. The temperature distribution map of the Sichuan Basin for depths of 3,000–9,000 m presented the central and southern areas are characterized by relatively higher temperatures while the northwestern and northeastern areas are characterized by lower temperatures. Strata temperature in the central and southern areas exceeded 150°C as the burial depth reached 5,000 m. At the depth of 7,000 m, the temperatures in the central and southern areas were above 180°C, which is the threshold temperature for hot dry rock (HDR), while the temperatures in the northwestern and northeastern areas were below 160°C, which is close to the lower limit for oil crude oil cracking. The central and southern areas are favorite zones for the exploration of geothermal energy, conversely, the relatively lower temperatures in the northern, northwestern, and eastern areas are conducive to the presence of oil and gas. The unevenly distribution of geothermal field were controlled by the thicknesses of sedimentary layer and the crust, which indicates the lithosphere flexure and thickening caused by compression and depression, rapid deposition in the foreland depressions. The results can provide geothermal understandings for the exploration and development of the petroleum and geothermal resources and could serve as a reference for geodynamic studies in the Sichuan Basin.
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