Development Of Geothermal Resources Research Articles

Main Controlling Factors and Formation Mode of Geothermal Anomaly in Eastern Chenghe Mining Area of Weibei Coalfield

Geothermal anomaly has gradually become a prominent issue affecting the efficient mining of coal with the depth of coal mining increasing in eastern Chenghe mining area of Weibei coalfield. Here, we comprehensively investigated the distribution characteristics of the present geothermal field, analyzed the main controlling factors, and constructed forming mode of geothermal anomaly by the temperature measurement in surface borehole and underground water, combined with coal-rock thermal conductivity test. The results show that the geothermal gradient ranged from 25.7°C/km to 54.3°C/km. The areas with geothermal gradient greater than 30°C/km accounted for 88.31%, and there was the highest gradient value in the southeast F1 fault zone. The heat flow was between 66.81 mW/m2 to 128.49 mW/m2, which belonged to the obvious high heat flow area. Under the action of the main controlling factors such as fault, fold, coal-rock thermal conductivity, and groundwater activity in the region, the geothermal gradient and geothermal heat flow values showed an increasing trend from northwest to southeast. According to the distribution characteristics of heat flow and the action mechanism of main controlling factors, the geothermal anomaly in the study area was finally divided into two forming modes, i.e., fault-deep circulating hot water uplifting type and coal seam heat resistance-fold type. The research provides guidance for the geothermal hazard prevention of coal mine and the rational development and utilization of geothermal resources.

Māori values in geothermal management and development

When Māori arrived at Aotearoa (New Zealand), they enjoyed an exclusive relationship with their country’s geothermal resources, which they valued spiritually and physically. After European settlement, this relationship was no longer exclusive, and Māori thereafter held spiritual, physical, and additionally, political values towards geothermal resources in their attempt to remain relevant in Aotearoa’s geothermal industry. In recent history, these values have been overlooked and forgotten by many, including some Māori, due to a certain ignorance displayed by those who practised modern and more invasive forms of geothermal management and development. The presented study involved a series of wānanga (Māori-based workshops), first to discuss the history regarding these values and thereby recognising where they originated from, and second to reinterpret these values as indicators of cultural sustainability, such that they may be more practically accounted for when considering the management and development of geothermal resources in Aotearoa.

The Estimation of Geothermal Reservoir Temperature Based on Integrated Multicomponent Geothermometry: A Case Study in the Jizhong Depression, North China Plain

The coal-dominated energy structure in the Beijing–Tianjin–Hebei region has caused serious air pollution and contradicts the construction of a clean, low-carbon, safe and efficient energy system. Substituting geothermal energy for fossil energy such as coal can effectively alleviate this problem. Located in the hinterland of the Beijing-Tianjin-Hebei region, the Jizhong Depression is rich in geothermal resources and has great development potential, though the degree of current development and utilization is not high. Vigorously developing geothermal energy can not only effectively alleviate the air pollution problem in the Beijing–Tianjin–Hebei region, but also optimize the regional energy structure. Geothermal reservoir temperature determines the development and utilization value of geothermal resources, and accurate evaluation of the geothermal reservoir temperature of geothermal resources can provide a reliable basis for the subsequent development of geothermal resources in the Jizhong Depression. Aiming at the commonly used sandstone geothermal reservoir and carbonate geothermal reservoir in the Jizhong Depression, this paper collected 24 sandstone geothermal reservoir geothermal fluids and 14 carbonate geothermal reservoir geothermal fluids in the central-southern area of the Jizhong Depression and a water chemistry test was carried out. According to the test results of water chemistry, the temperature of the geothermal reservoir is estimated by using the cation geothermometer, the SiO2 geothermometer and the multi-mineral equilibrium method, and it is compared with the actual temperature measurement results of the boreholes. The results show that the direct use of a geothermal geothermometer for calculation will cause large errors. Through water–rock balance analysis, the use of a Na-K-Mg balance diagram, SiO2 and 1000/T relationship diagram and Na/K and 1000/T relationship diagram can determine whether the geothermal fluid is suitable for the geothermometer, which can effectively reduce the error. The chalcedony geothermometer in the central and southern part of the Jizhong Depression is the most suitable. The multi-mineral balance method, the Na-K geothermometer and the K-Mg geothermometer have also achieved good results, while the quartz and Na-K-Ca geothermometers are not suitable for the south-central Jizhong Depression area.

Isotopic and Hydrogeochemical Characteristics and Genesis of Warm Springs in the Jiangcang Basin, Qinghai, China

The Jiangcang Basin is a Cenozoic faulted basin, where many low-temperature warm springs are exposed, with the highest temperature being 36.6°C. The study of the hydrogeochemical characteristics of the geothermal fluids of these warm springs can effectively clarify the genetic mechanisms of the geothermal resources in the Jiangcang Basin and thus is of great significance for the development and utilization of geothermal resources in the Qinghai Province. Using the geothermal and geological conditions of the Jiangcang Basin, this study analyzed the hydrochemical and isotopic characteristics of water samples collected from cold water and from four warm springs in the Jiangcang Basin, obtaining the following results. The four warm springs have the hydrochemical types of HCO3-Ca·Mg, HCO3-Ca·Na·Mg, and HCO3·SO4-Na·Ca and total dissolved solids (TDSs) of 720.4–1,663 mg/L. Moreover, no significant positive correlation is found between Cl− and other ions in the warm springs. The results of isotopic analysis show that the warm springs are mainly recharged by atmospheric precipitation and meltwater from ice and snow, with a recharge elevation of 4,401–4,501 m. Furthermore, the geothermal reservoirs in the Jiangcang Basin have temperatures of 51–83°C and circulation depths of 1,848–2,610 m. Atmospheric precipitation and the meltwater from ice and snow infiltrate downward in high mountain areas and form runoffs along the tectonic channels in the basin. After being heated through deep circulation, they migrate upward along fault fracture zones under the influence of faults and the water blocking of mudstones, during which they cool by thermal conduction and mixing with shallow cold groundwater. Finally, the mixed water is exposed in the form of low-temperature tectonic warm springs. The results of this study can provide data for the exploitation and utilization of geothermal resources in the Qinghai Province.

Geothermometry in High-Temperature Reservoirs of the Geothermal Springs in Southern Thailand: Insights from Cations and Silica Geothermometers

Geothermal springs have provided a unique opportunity to study the geothermal system of geological processes. A reservoir temperature estimation based on the chemical geothermometers is vitally essential for assessing the exploration and development of geothermal resources. The paper represents the various techniques of geothermometers with comparisons between the silica (quartz and chalcedony) and the cation geothermometers (Na–K–Ca and K–Mg) for the high exit temperature (temp. ≥55°C) of geothermal springs in southern Thailand. The Na–K–Ca geothermometer presented more elevated reservoir temperatures than the K–Mg, silica and chalcedony geothermometers, about 20–30◦C. The preliminary assumed difference between the geothermometers may indicate that the shallow subsurface conditions are mixed with groundwater

Experimental study of the influence of temperature and cooling method on dynamic mechanical properties and damage of granite

AbstractThe change in mechanical properties of high‐temperature rock after cooling treatments is getting increasing attention. However, only a few studies have been conducted on the dynamic characteristic parameters. Therefore, this study aims to perform a dynamic damage analysis of high‐temperature rocks subjected to different thermal shocks. Accordingly, the specimens were grouped and heated to 200°C, 400°C, 600°C, and 800°C, and they were cooled by natural, water, and liquid nitrogen cooling. Ultrasonic detector tests, the split Hopkinson pressure bar experiments, and scanning electron microscope tests of the high‐temperature granite specimens were conducted using different cooling methods. Subsequently, the change rules of dynamic stress–strain curves and properties were calculated, and the morphology and micromorphology of fragments were compared. Based on the outcomes, the thermal shock damage and impact damage evolution were evaluated and quantified. The findings revealed that when the treatment temperature increases, the dynamic peak stress and elastic modulus decrease, while the peak strain increases, and the effect of rapid cooling was more significant in the influence of rock dynamic characteristics. Moreover, when the damage factor is more than 0.51, the change of dynamic stress‐strain is accelerated, leading to the instability of the structure under the impact load. The research results are expected to provide an adequate theoretical basis for the development and utilization of geothermal resources and underground engineering applications.

Visualization Analysis on the Current Status and Development Trend of Geothermal Research: Insights Into the Database of Web of Science

Geothermal energy is considered a renewable, clean, and environmentally friendly energy source. In addition, it is efficient and relatively cost effective. Therefore, the demand for the development and utilization of geothermal resources is increasing annually. To understand the current status and developments within the context of geothermal research, quantitative and qualitative analyses were carried out by combining two visualization software applications, namely, VOSviewer and CiteSpace; this analysis also entailed the secondary development of R language. The results showed that the USA, China, and Germany are the main contributors to geothermal research. We also found that geothermal research hot spots encompass five geothermal research clusters, such as renewable energy utilization, heat flow, numerical simulation, geochemistry, and groundwater. In addition, the strategic diagram and thematic structure revealed how geothermal research has evolved over time. Finally, the timeline view and burst term highlight the possible frontiers of geothermal power generation, enhanced geothermal systems, and ecological environment protection. These insights will provide scholars and policymakers with a systematic understanding of the current research and directions for future studies.

Processing Method of Soil Temperature Time Series and Its Application in Geothermal Heat Flow

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.

Subsurface temperature prediction by means of the coefficient correction method of the optimal temperature: A case study in the Xiong’an New Area, China

Accurate estimation of the earth’s interior temperature is extremely important for studying fundamental scientific and applied geothermal problems. Existing temperature estimation methods cannot provide reliable accuracy in the cross-borehole space and beyond the borehole’s depth; however, resistivity could overcome this difficulty as a temperature-dependent proxy parameter. At present, this approach is based on the use of purely empirical formulas, whose validity is unjustifiably postulated to be invariant with respect to geologic settings. We develop an electromagnetic (EM) geothermometer based on the coefficient correction method of the optimal temperature (CCMOT). This geothermometer can accurately determine the relationship between the normalized resistivity and temperature in an underground space based on resistivity-temperature logging data and EM data; therefore, a visualized temperature distribution can be calculated. The CCMOT is applied to the subsurface temperature prediction in the Xiong’an New Area, with an accuracy of 86.69%–97.25%. Sensitivity analysis of the key variables of the CCMOT reveal that the CCMOT has relatively little dependence on the number of constraining boreholes and the optimization of the subdivision spacing of the logging data can significantly improve temperature prediction accuracy. The CCMOT can be used to determine the distribution of the heat structure of the reservoir and to interpret the geothermal field. In addition, the CCMOT is of great significance to the evaluation, scientific development, and sustainable use of geothermal resources.

Study on the Thermophysical Properties and Influencing Factors of Regional Surface Shallow Rock and Soil in China

Thermophysical properties of rock and soil are important parameters that affect the efficiency of shallow geothermal energy utilization. This paper analyzes the thermophysical parameters (specific heat capacity and thermal conductivity) and their influencing factors based on 6467 sample data in 24 provincial capitals, China. The statistical distributions of thermophysical properties are analyzed based on histogram plots. Linear regression analysis is conducted to investigate the correlation between thermophysical properties and lithology (classified as metamorphic rocks, igneous rocks, chemical sedimentary rocks, clastic sedimentary rocks, and loose sediments in this study)), density, and water content. The results show that the thermophysical properties are influenced predominantly by lithology. The measured values of thermophysical properties generally show normal distribution characteristics. The specific heat capacity of loose sediments is relatively high, the thermal conductivity of other four types are relatively high. The specific heat capacity is negatively correlated with density, positively correlated with water content, whereas thermal conductivity is positively correlated with density, and negatively correlated with water content. The findings obtained in this study provide evidence and guidelines for the investigation, evaluation, and development of shallow geothermal resources.

Quantitative prediction and evaluation of geothermal resource areas in the southwest section of the Mid-Spine Belt of Beautiful China

ABSTRACT The geothermal resources in the southwest section of the Mid-Spine Belt of Beautiful China are abundant, but the quantitative prediction and evaluation of geothermal resources are very difficult. Based on geographic information system (GIS) and remote sensing (RS) platforms, six impact factors, namely land surface temperature, fault density, Gutenberg–Liszt B value, formation combination entropy, distance to river and aeromagnetic anomaly were selected. Through the establishment of the certainty factor model (CF), weights of the information entropy certainty factor model (ICF) and weights of the evidence certainty factor model (ECF), the geothermal potential in the study area were predicted quantitatively. Based on the ECF results, the six main geothermal resource areas were delineated. The results show that (1) ECF had high prediction accuracy (success index is 0.00405%, area ratio is 0.867); (2) The geothermal resource areas obtained were Ganzi–Ya’an–Liangshan, Panzhihua–Liangshan, Dali–Chuxiong, Nujiang–Baoshan, Diqing–Dali, and Lijiang–Diqing. The results provide a basis for the effective development and utilization of geothermal resources in the southwest section of the mid-ridge belt.

Experimental comparison of mechanical properties and fractal characteristics of geothermal reservoir rocks after different cooling treatments

In the process of geothermal well drilling, the high-temperature rock in the reservoirs is cooled by different cooling media, which leads to the change of mechanical properties, affecting the rock-breaking efficiency of the bit. Sandstone and granite were taken as the research objects and heated to 400 °C, 600 °C, and 800 °C, then were cooled by natural, water, and liquid nitrogen (LN2) cooling. Ultrasonic detector tests, the split Hopkinson pressure bar (SHPB) experiments, and scanning electron microscope (SEM) tests were conducted. The effects of heating temperature and cooling methods on the dynamic mechanical properties were quantified and analyzed. Thermal shock damage evolution and the damage mechanism of high-temperature rock under different cooling ways were discussed. The fractal method was applied to the analysis of fragment distribution, to obtain the corresponding relationship between fractal dimension and heat treatment temperature and cooling methods. The research results showed that thermal and cooling treatment has a significant effect on the mechanical properties of rock. With the increase of the treatment temperature, the dynamic peak stress decreased, and the peak strain increased. The temperature sensitivity of sandstone to temperature was higher than that of granite, while sandstone was more significantly affected than granite in terms of the sensitivity of the cooling method. Fractal dimension could be used to analyze the fragmentation of high-temperature rock cooled in different ways after impact. The experimental results were expected to provide an adequate theoretical basis for the development and utilization of geothermal resources.

Flow Path of the Carbonate Geothermal Water in Xiong’an New Area, North China: Constraints From 14C Dating and H-O Isotopes

Studying the flow path of geothermal water in geothermal fields is an important basis for the scientific development and management of geothermal resources. However, due to the influence of engineering volume, economic benefits and demand, it is very difficult to fully grasp the flow path of deep geothermal water in large areas. The use of hydrogeochemical tracers to determine the flow path of geothermal water is a scientific and effective research method. In order to accurately describe the flow path of carbonate geothermal water in the Xiong’an New Area and its surrounding areas, this study systematically analyzed the 14C, 18O, and 2H data of carbonate and Cenozoic sandstone geothermal water, Quaternary groundwater, as well as mountain spring water of the study area. Based on these results, we can conclude that 1) The 14C, d, and 18O values are favourable clues for indicating the circulating runoff conditions and runoff paths of geothermal water. 2) The salinity of the Xushui-Wenan and Lilan transfer zone are <3 g/l, the 14C values are lower than 25000 years, the d value is higher, and the phenomenon of “18O drift” is weak, all these indicating the dominant flow path of carbonate geothermal water, featured by relative lower temperature. 3) The salinity of karst geothermal water in the southwest of Gaoyang low uplift, Rongcheng uplift and Niutuozhen uplift is > 3 g/l, the 14C values are higher than 40,000 years, the d value is lower, and the phenomenon of “18O drift” is obvious, all these indicating that the tectonic sites are the convergence areas of regional karst geothermal water, featured by relative high temperature. 4) The hydrochemical indicators combined with previous carbonate groundwater flow field indicate that the recharge of carbonate geothermal water in the Xiong’an New Area may not only drive from the western Taihang Mountains, but also along the Xushui-Wenan transfer zone and the Lilan fault, with the recharge of carbonate groundwater from the Cangxian uplift from east to west. By further identifying and defining the dominant flow path and supply direction of carbonate geothermal water in the Xiong’an New Area and surrounding areas, it provides strong support for the scientific development of regional carbonate geothermal water.

Machine learning in subsurface geothermal energy: Two decades in review

This paper reviews the trends in applying machine learning to subsurface geothermal resource development. The review is focused on the machine learning applications over the past two decades (from 2002 to 2021) to determine which machine learning algorithms are being used. In addition, the review seeks to determine what types of problems are being addressed with machine learning and how machine learning is aiding decision-making and problem-solving for subsurface aspects of the geothermal industry. The study shows that there has been a steady increase in the application of machine learning in the geothermal industry over the past 20 years, with an exponential increase in machine learning applications from 2018 to 2021. Several research areas associated with geothermal resource development were reviewed, including exploration, drilling, reservoir characterization, seismicity, petrophysics, reservoir engineering, and production and injection engineering. The study reveals that the field of reservoir characterization had the most significant applications of machine learning in the geothermal industry. Though machine learning has been applied across all the geothermal research areas we investigated, this study shows that there are still opportunities to improve and expand the adoption of machine learning in exploration, drilling, and seismicity. The main challenges that would need to be addressed are ensuring researchers have access to data, curating the data to be suitable for machine learning, and training geothermal industry students and professionals on artificial intelligence related to the energy sector.

Study on Chemical Genesis of Deep Geothermal Fluid in Gaoyang Geothermal Field

Geothermal resources are clean energy with a great potential for development and utilization. Gaoyang geothermal field, located in the middle of the raised area in Hebei province, China, is one of the three major geothermal fields in the Xiong’an New Area. With the development of the Xiong’an New Area, this geothermal field has become a research hotspot. According to the latest survey, the bottom-hole temperature of the D34 and D35 areas in the north of Gaoyang geothermal field is 149°C and 116°C, respectively, which indicates favorable target areas for geothermal exploitation The circulation mechanism and chemical origins of geothermal fluid are unclear in the Gaoyang geothermal field, which hinders the evaluation of geothermal resources in this region. Therefore, water chemistry and isotopic studies were performed on the Gaoyang geothermal fluid to understand the genesis of the Gaoyang geothermal field. Piper trigram and Na-K-Mg software were also used to explore the genesis of the underground hot water. Combined with stratigraphy and geothermal geology, it can be concluded that the primary hydrochemical type of the Gaoyang geothermal field is Na-HCO3·Cl. In the process of upward migration of geothermal water, leaching and cation alternating adsorption took place, and finally, high TDS geothermal water was formed. Our results are helpful for geothermal resource evaluation and utilization and provide scientific guidance for the sustainable development of geothermal resources.

Numerical simulation of mid-deep geothermal system based on dynamic mesh adaptive finite element

Numerical simulation is an important tool in the study of geothermal science and even the development and utilization of geothermal resources. Aiming at the development of middle and deep geothermal resources, this paper takes the numerical simulation of U-shaped heat exchange well as the research object. Based on Fourier’s law and heat conduction equation, the dynamic mesh adaptive finite element method is used to simulate the heat transfer process. The results show that the fixed mesh non-adaptive finite element method lacks a feasible error control mechanism, and the adaptive high-order finite element method with dynamic mesh and adaptive time step control can effectively simulate the process of geothermal energy transmission.

Joint optimization of constrained well placement and control parameters with a quantum-inspired cell-based quality gate function

Well placement and parameter optimization (WPPO) is an essential step in hydrocarbon, geothermal and water resources development which has complexities and difficulties. In fact, high computational cost can be the most important obstacle in WPPO problems. Population-based metaheuristics algorithms (PBMAs) are the most widely utilized ones for WPPO problems. However, these methods suffer from the issue that at each iteration, the minimum number of simulation run is at least equal to the population size. Knowing this, in order to enhance the efficiency of these methods, in this study, we introduced a cell-based quality gate function (CBQGF) which is inspired from quantum gates in quantum computing. The CBQGF is incorporated in our previously introduced inter-distance algorithm (IDC) which we called CBQG-IDC. Since, CBQG sets a condition for each location during the optimization process, locations with poor cell properties will be filtered out to increase the rate of convergence considerably. We applied the CBQG-IDC to two universally popular global optimization methods, genetic algorithm (GA) and particle swarm optimization (PSO) and compared the results to the IDC limited algorithm. In all scenarios, net present value (NPV) was considered as the fitness value and all joint optimization of locations and well associated parameters were conducted simultaneously. The results showed CBQG-IDC with a much higher rate of convergence compared to IDC, while its performance is highly dependent on constant parameters. Ultimately, the proposed CBQG-IDC can be applied to any optimization algorithm for any placement optimization problem in Euclidian geometry to save the computational cost. • A cell-based quality gate function (CBQGF) has been introduced to optimization process. • The proposed CBQGF can be coupled with any arbitrary optimization and applied to any placement optimization problem. • The CBQGF has increased the rate of convergence significantly with substantial computation cost saving. • The threshold value of the cell property and its associated constant have great influence on the search flexibility.

Geothermal Resource Exploration in Magmatic Rock Areas Using a Comprehensive Geophysical Method

Geothermal resources have significant development and usage potential. It is critical to conduct geological investigation of geothermal resources prior to mining, so as to deepen our knowledge and comprehension of geothermal resources. Ground water is heated by magmatic rocks and geothermal resources can be created in magmatic rock areas. However, their communication is weak, and the depth of burial is typically great. It is difficult for traditional geophysical methods, such as induced polarization method, to achieve useful exploration depths, and they have low accuracy. In this article, a comprehensive geophysical method, based on the controlled source audio-frequency magnetotelluric method (CSAMT) and transient electromagnetic method (TEM), is applied to geothermal exploration in a magmatic rock area. This method compensates for the shortcomings of a single method and achieves a good exploration effect, thereby providing a reliable geological foundation for further development and utilization of geothermal resources.

Changes in mechanical properties and fracture behaviors of heated marble subjected to liquid nitrogen cooling

Liquid nitrogen (LN2) fracturing is a novel waterless fracturing technology that has significant potential for application in the development of geothermal resources. In this study, we performed physical and mechanical experiments on marble samples to determine the influence of LN2 cooling on the damage behavior of hot dry rock (HDR). Specifically, we evaluated the changes in the internal structure, mechanical properties, and fracture behavior of the marble samples after subjecting them to thermal shock. The results revealed that the porosity of the heated marble increased significantly after LN2 cooling, whereas the P-wave velocity, compression strength, and elastic modulus decreased. The complexity of the fracture propagation process and the induced fracture morphology of the marble samples subjected to thermal shock increased under uniaxial compression. Furthermore, the changes in these properties increased with the increase in the marble temperature. Compared to air cooling, LN2 cooling significantly changes the physical and mechanical properties and fracture behavior of marble. Based on the coupled thermal–mechanical simulations from macroscopic and microscopic perspectives, the thermal damage that occurs in heated marble subjected to rapid cooling is primarily due to the temperature gradient inside the rock and the difference in the thermal expansion of adjacent mineral particles.

Experimental study of horizontal ground heat exchangers embedded in the backfilled mine stopes

Abundant geothermal resources are stored in underground mines in China. In order to realize the green cooperative development of deep mineral resources and geothermal resources, the heat storage functional backfill technology can be used to form artificial thermal reservoir, and the geothermal energy can be extracted through the buried pipes, so as to expand the auxiliary value and reduce the cost of backfill mining. It's important to investigate the heat storage/release behavior of the backfill body with buried pipes and its influencing factors for improving the geothermal energy utilization efficiency. In view of the limitations of field experiments, a scale model test platform for backfill coupled heat exchanger of mine was established in this paper. According to the heat transfer differential equations, the similarity criterion number and similarity constant that should be satisfied between the model and the prototype were deduced, and the effects of different pipe arragement, flow rate of heat-carrying fluid, surrounding rock temperature on the heat transfer performance of the backfill coupled heat exchanger were studied. Based on the heat balance, the total energy efficiency of the backfill coupled heat exchanger system was calculated. The experimental results showed that with the increase of the distance between pipes, the pipe length, the flow rate and the surrounding rock temperature, the heat extraction and water outlet temperature of the system all increased. With the increase of the velocity of heat-carrying fluid, the water outlet temperature decreased. The increase in the number of pipes in the backfill body and the decrease in the distance between pipes lead to the increase in thermal interference and thus the decrease in heat extraction, but the decrease value is less than the increase value of heat charging caused by the increase in pipe length (serpentine) and flow rate (double U-type). The total energy efficiency of the system was the highest, which was 47.9%, when the serpentine pipe arrangement was adopted, the working fluid velocity was 0.7 m/s, and the surrounding rock temperature was 35°C. According to the scale model, 1.06 × 109 kJ of heat can be obtained from the mines a year by applying BCHE system in engineering practice.