| Abstract |
The thermal regime of the basin is of great significance for regional geothermal energy resource assessment. This paper studies the thermal structure differences and controlling factors, thermal storage system types and favorable geothermal resource distribution in the Sichuan Basin based on the basic geothermal parameters and basin tectonic evolution process from wells drilled in the Sichuan Basin. The study concluded that there are three types of thermal structures in the Sichuan Basin: the Caledonian thermal structure controlled by the differences in basal heat flow background and differences in thermal conductivity of fractured trough rocks, which is characterized by stable thermal state and low geothermal flow with small differences in planar distribution; the Hercynian thermal structure controlled by Emeishan Traps basalt eruption and basin tension, which is characterized by anomalously high geothermal flow distribution; and the Middle Cenozoic thermal structure formed by strong orogenesis at the basin margin, which is characterized by high geothermal flow distribution at the basin margin and intra-basin strong tectonic activity. According to the difference of thermal structure, three thermal storage systems of two types, the Aurignacian-Early Cambrian and Late Permian-Middle Triassic closed layer-controlled thermal storage systems and open folded thermal storage systems, are proposed. Taking into account the distribution of geothermal heat flow, the main control factors and the division of thermal storage systems, three types of favorable geothermal resources and their distribution are proposed: deep circulation geothermal resources in fracture zones, anomalous high temperature geothermal resources in strong tectonic background and early deep buried geothermal resources. |