Abstract:
This paper is the result of geothermal geological survey engineering.
Objective The Gonghe Basin, situated on the northeastern margin of the Qinghai−Tibet Plateau, is a significant experimental area for the exploration and development of hot dry rock (HDR) in China. The formation mechanisms of HDR within the Gonghe Basin remain controversial and have attracted considerable research attention. The current thermal state is of great significance for a deeper understanding the distribution patterns and formation mechanisms of high−temperature geothermal reservoirs.
Methods In this study, extensive geophysical exploration and drilling data are integrated to describe the geological and geothermal architecture of the Gonghe Basin. A two−dimensional temperature field profile across the east−west axis is established through numerical simulation. Based on these results, the resource potential of HDR is assessed, and the key factors controlling HDR formation are analyzed.
Results The Gonghe Basin hosts abundant HDR resources, with an estimated 2.48×1021 J within the depth of 5 km. The two−dimensional numerical simulation reveals significant temperature field variations between the eastern and western parts of the basin. The temperature field variations are consistent with the distribution of the basin's basement depth, which decreases from west to east. High−temperature anomalies are observed in the northeastern region, particularly around the Xinjie−Waliguan uplift belt.
Conclusions On the basis of understanding the knowledge of predecessors, this paper proposes a comprehensive HDR formation mechanism from the perspectives of geological, geothermal, and geophysical backgrounds. The formation of HDR in the Gonghe Basin is controlled by multiple factors, including continuous heating by partial melting, heating and conducting heat by granite, heat controlling by neotectonic uplift and denudation, and heat preservation and accumulation by sedimentary covers.
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