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Enhanced geothermal systems (EGSs) are expected to be one of the most promising methods of supplying energy to meet the world’s increasing energy demand. However, little attention has been paid to the influence of the number of production wells on the heat extraction performance of an EGS. A series of numerical simulations is organized in this work with three cases: Case 1 (one production well), Case 2 (two production wells), and Case 3 (three production wells). The results indicate that a slight temperature difference exists among the three simulation cases at the planes X-Y (Z = 0) and Y-Z (X = 0), while Case 1 ensures a greater cooling area, and the more production wells, the smaller the cooling area during the heat extraction in plane X-Z (Y = 0). In addition, the continuous injection of cooling water from the injection well and its arrival at different reference points enable the temperature at each point to declining with a variable amplitude of variation. This work also sets an efficiency (ef) to investigate the temperature variation in the EGS, where Case 1 exhibits a similar variation as Case 2, which is also similar to Case 3. It is hoped that this work will play a guiding role in EGS-related exploration and exploitation.

The Late Paleozoic Ice Age (LPIA; ca. 335–260 million years ago) was one of the most significant glacial events in Earth’s history. It records cycles of ice advance and retreat in southern high-latitude Gondwana and provides a deep-time perspective for climate–glaciation coevolution. However, climate records using clay mineral proxies from the LIPA are poorly developed in low latitudes, particularly in the North China Plate (NCP) on the eastern Paleo-Tethys. We address this through a detailed mineralogical study of the marine–continental sedimentary succession in the Yuzhou Coalfield from the southern NCP. We apply biostratigraphy and high-resolution clay mineral composition to reconstruct the latest Carboniferous to early Permian chronostratigraphy and climate change. The Benxi, Taiyuan, and Shanxi formations in the study area are assigned to the Gzhelian, Asselian–Artinskian, and Kungurian-Roadian stages, respectively, and the Carboniferous and Permian lithostratigraphic units across the NCP recognized as widely diachronous. Under scanning electron microscopy, the detrital micromorphology of kaolinite is mostly found as irregular fragments with sizes of 1–5 μm. Illite crystallization varies from 0.22 to 1.88 ∆°/2θ (x̄ = 0.49 ∆°/2θ) and indicates changes in kaolinite content to be a robust proxy for paleoclimate reconstruction. Kaolinite data show alternating warm-humid and cool-humid climate conditions that are roughly consistent with the calibrated glaciations and nonglacial interval successions recognized in high-latitude Gondwana. These include the Asselian-early Sakmarian and late Sakmarian-early Artinskian glacials and the climatic transition to glacial P3 during the Roadian. Our results indicate a comparatively cool-humid and warm-humid climate mode in low-latitude NCP during glacial and nonglacial periods, respectively. This is a significant step toward connecting climate change in low-latitude to high-latitude glaciation during the LPIA in eastern Paleo-Tethys.

Nowadays, geothermal resources have become one of the important means for mankind to solve global energy problems and environmental problems, and the exploration and development of geothermal resources are of great significance for sustainable development. However, in view of the complex geological background of the plateau region, the number of heat flow measurement points in this area is small or even blank, thus becoming an important factor limiting the exploration of geothermal resources in this region. In this article, a new model based on Fourier analysis and heat conduction principle is established to process and analyze the long-term monitoring data of soil temperature and eliminate the influence of temperature change on soil temperature as far as possible, so as to improve the calculation accuracy of soil conduction heat dissipation. The experimental results show that the fluctuation range of soil temperature at 20 cm before the correction was large, and the fluctuation range was 2.58°C–14.284°C, which was because the soil here was closer to the land surface and was affected too much by the temperature fluctuation, and as the soil depth deepened, the temperature fluctuation slowly became smaller, and the fluctuation range was 6.67°C–11.15°C at 50 cm, but the effect of temperature fluctuation was still obvious. Also, the fluctuation range was basically reduced within 0.3°C after temperature correction. In this method, the thermal diffusion coefficients of the soil at different depths can be obtained, and the calculated temperatures at the corresponding depths can also be obtained, which can be used to infer the approximate ground temperature gradient of the measured area. This study aims to develop a convenient and fast model for processing soil temperature time series and to provide technical support for developing geothermal resources in highland areas or assessing the geothermal potential of the region.