The Experts below are selected from a list of 330 Experts worldwide ranked by ideXlab platform
Xianzhi Song - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of characteristics of a single u tube downhole heat exchanger in a geothermal well
Geothermics, 2018Co-Authors: Xianzhi Song, Gensheng Li, Zihan MuAbstract:Abstract Heat extraction from a geothermal Reservoir using a single U-tube in a Reservoir has been applied in the field. The advantages include extracting only heat instead of water. Based on the geological data of Bazhou geothermal field, China, a three-dimensional steady state numerical model, including the U-tube, wellbore and Reservoir is established to analyze the entire flow field comprehensively. The performance of the exchanger is studied through investigation on the influences of four important geological parameters of depth, Porosity, permeability and heterogeneity of the formation. Simulation values are validated by results obtained from field tests. Results indicate that the overall flow velocity in the geothermal Reservoir is relatively low compared with the flow in the wellbore mainly due to the high flow resistance. In addition, the mass flow rate can hardly affect the flow in the Reservoir. Under the conditions of this study, the depth of the geothermal field, the Reservoir Porosity and the heterogeneity of the geothermal formation may hardly affect the performance of the U-tube. However, if it is possible, it is better to install the single U-tube in the homogeneous area of the Reservoir, which may obtain better heat extraction effect. The results in this paper could provide implications for further study of geothermal energy exploitation.
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numerical investigation on the Reservoir heat production capacity of a downhole heat exchanger geothermal system
Geothermics, 2018Co-Authors: Yu Shi, Xianzhi Song, Ruiyue Yang, Zhonghou Shen, Zehao LyuAbstract:Abstract The downhole heat exchanger (DHE) geothermal system is commonly used for space heating in the residential and commercial buildings. The Reservoir properties have significant effects on the Reservoir heat production capacity of DHE geothermal system. However, to the best of our knowledge, few researches are conducted to study this problem. In this paper, an unsteady-state fluid flow and heat transfer model considering natural convection for DHE system is presented. Subsequently, the temperature and velocity fields are analyzed comprehensively to understand the thermal process in geothermal Reservoir. The influences of key parameters, including Reservoir Porosity, permeability and thermal conductivity coefficient of rock, on the heat production capacity are studied. The simulation results depict that the natural convection velocity near the wellbore is the largest, and the temperature gradient keeps constant along the vertical direction with time. The impact scopes of velocity and temperature fields both remain in a small range within the heating period. The Reservoir heat production capacity decreases with the increase of Porosity, while it does not reveal obvious trends because of a variation in permeability. As rock thermal conductivity rises, Reservoir heat production capacity is improved. As a result, it is inferred that if only natural convection exists in Reservoir, DHE system could be more suitable for the geothermal field with smaller Porosity. The key findings of this work can be used to provide guidance for choosing the appropriate geothermal Reservoir for the DHE geothermal system.
Zihan Mu - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of characteristics of a single u tube downhole heat exchanger in a geothermal well
Geothermics, 2018Co-Authors: Xianzhi Song, Gensheng Li, Zihan MuAbstract:Abstract Heat extraction from a geothermal Reservoir using a single U-tube in a Reservoir has been applied in the field. The advantages include extracting only heat instead of water. Based on the geological data of Bazhou geothermal field, China, a three-dimensional steady state numerical model, including the U-tube, wellbore and Reservoir is established to analyze the entire flow field comprehensively. The performance of the exchanger is studied through investigation on the influences of four important geological parameters of depth, Porosity, permeability and heterogeneity of the formation. Simulation values are validated by results obtained from field tests. Results indicate that the overall flow velocity in the geothermal Reservoir is relatively low compared with the flow in the wellbore mainly due to the high flow resistance. In addition, the mass flow rate can hardly affect the flow in the Reservoir. Under the conditions of this study, the depth of the geothermal field, the Reservoir Porosity and the heterogeneity of the geothermal formation may hardly affect the performance of the U-tube. However, if it is possible, it is better to install the single U-tube in the homogeneous area of the Reservoir, which may obtain better heat extraction effect. The results in this paper could provide implications for further study of geothermal energy exploitation.
Gensheng Li - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of characteristics of a single u tube downhole heat exchanger in a geothermal well
Geothermics, 2018Co-Authors: Xianzhi Song, Gensheng Li, Zihan MuAbstract:Abstract Heat extraction from a geothermal Reservoir using a single U-tube in a Reservoir has been applied in the field. The advantages include extracting only heat instead of water. Based on the geological data of Bazhou geothermal field, China, a three-dimensional steady state numerical model, including the U-tube, wellbore and Reservoir is established to analyze the entire flow field comprehensively. The performance of the exchanger is studied through investigation on the influences of four important geological parameters of depth, Porosity, permeability and heterogeneity of the formation. Simulation values are validated by results obtained from field tests. Results indicate that the overall flow velocity in the geothermal Reservoir is relatively low compared with the flow in the wellbore mainly due to the high flow resistance. In addition, the mass flow rate can hardly affect the flow in the Reservoir. Under the conditions of this study, the depth of the geothermal field, the Reservoir Porosity and the heterogeneity of the geothermal formation may hardly affect the performance of the U-tube. However, if it is possible, it is better to install the single U-tube in the homogeneous area of the Reservoir, which may obtain better heat extraction effect. The results in this paper could provide implications for further study of geothermal energy exploitation.
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feasibility analysis of coiled tubing drilling with supercritical carbon dioxide
Petroleum Exploration and Development, 2010Co-Authors: Z Shen, H Wang, Gensheng LiAbstract:Abstract Supercritical CO2 (SC-CO2) fluid has the properties of low viscosity and high diffusion capacity near to gas, and higher density near to liquid. Compared with nitrogen, air, liquid, aerated fluid, foam and other drilling fluids, the supercritical CO2 fluid has a wide range of density which can not only allow it to generate enough torque to run a downhole motor, but also ensure the downhole condition is in an underbalanced state while drilling. Even if the supercritical CO2 fluid invades into Reservoir, the Reservoir will not be damaged, on the contrary, it can increase the Reservoir Porosity and permeability further more, reduce flow resistance, and enhance production and recovery. Meanwhile, the velocity of a supercritical CO2 jet is faster than that of water jet and the threshold pressure is lower also resulting in improved rock breaking. When the coiled tubing drilling with supercritical CO2 takes place, it can significantly decrease the coiled tubing drilling system pressure and expand the coiled tubing operating range, it is more suitable for slim hole, microhole, short radius horizontal wells, and complex structures wells. The coiled tubing drilling with SC-CO2 will bring an innovation in the drilling technology, and will become an efficient drilling technique for special Reservoir development.
Adrian Immenhauser - One of the best experts on this subject based on the ideXlab platform.
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dolomitization history and Porosity evolution of a giant deeply buried ediacaran gas field sichuan basin china
Precambrian Research, 2020Co-Authors: Yongjie Hu, Chelsea L Pederson, Lei Jiang, Xunyun He, Adrian ImmenhauserAbstract:Abstract The deeply buried (>7 km) upper Ediacaran (Sinian) Dengying Formation (ca. 551.1–541 Ma) in the Sichuan Basin, China, is the largest Precambrian dolostone gas Reservoir worldwide. Gas exploration from the Dengying Formation, however, is hampered by a limited understanding of its complex dolomitization history and Porosity evolution. New petrological, geochemical and petrophysical analyses were performed and are discussed here to develop a better understanding of the formation’s complexities. Microbialite, dolo-grainstone, and crystalline dolostone lithologies from the platform margin have high primary porosities relative to dolo-mudstone and less common microbialite lithologies from the low-energy platform interior. Spatially-variable primary Porosity was subsequently overprinted by meteoric dissolution and dolomitization, often inducing secondary Porosity. The various forms of dolomitization (sabkha, reflux, and burial dolomitization, and cementation) increased the resistivity of these rocks to chemical and physical compaction and Porosity destruction. In the deep burial domain, medium- to coarse-crystalline dolomite cements and saddle dolomite precipitated at fluid temperatures of 120–160 °C and 160–220 °C, respectively. The significance of deep burial dissolution is critically discussed and constrained by: (i) corrosion of late diagenetic minerals, (ii) pores cross-cutting (or forming around) stylolites, and (iii) the occurrence of solid bitumen in the center of secondary pores. Vuggy, inter- and intracrystalline pores developed during a late and deep burial stage, and comprise ca. 20% of the overall Dengying Reservoir Porosity. Mechanisms which induced corrosion at this burial stage include hydrothermal pulses and thermochemical sulfate reduction. Similar to many carbonate Reservoirs in the Phanerozoic, this study documents that the platform margin has better porosities and higher gas production compared to the platform interior due to its specific carbonate rock properties and diagenesis. Data shown here document the complex multiphase dolomitization history and high potential for gas production from deeply buried Precambrian dolostone Reservoirs.
Zehao Lyu - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation on the Reservoir heat production capacity of a downhole heat exchanger geothermal system
Geothermics, 2018Co-Authors: Yu Shi, Xianzhi Song, Ruiyue Yang, Zhonghou Shen, Zehao LyuAbstract:Abstract The downhole heat exchanger (DHE) geothermal system is commonly used for space heating in the residential and commercial buildings. The Reservoir properties have significant effects on the Reservoir heat production capacity of DHE geothermal system. However, to the best of our knowledge, few researches are conducted to study this problem. In this paper, an unsteady-state fluid flow and heat transfer model considering natural convection for DHE system is presented. Subsequently, the temperature and velocity fields are analyzed comprehensively to understand the thermal process in geothermal Reservoir. The influences of key parameters, including Reservoir Porosity, permeability and thermal conductivity coefficient of rock, on the heat production capacity are studied. The simulation results depict that the natural convection velocity near the wellbore is the largest, and the temperature gradient keeps constant along the vertical direction with time. The impact scopes of velocity and temperature fields both remain in a small range within the heating period. The Reservoir heat production capacity decreases with the increase of Porosity, while it does not reveal obvious trends because of a variation in permeability. As rock thermal conductivity rises, Reservoir heat production capacity is improved. As a result, it is inferred that if only natural convection exists in Reservoir, DHE system could be more suitable for the geothermal field with smaller Porosity. The key findings of this work can be used to provide guidance for choosing the appropriate geothermal Reservoir for the DHE geothermal system.