scholarly journals A new mathematical modeling approach for thermal exploration efficiency under different geothermal well layout conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Junyi Gao ◽  
Qipeng Shi
Keyword(s):  
Mathematical Modeling ◽  
Heat Transfer ◽  
Rock Mass ◽  
Temperature Distribution ◽  
Water Temperature ◽  
Production Well ◽  
Injection Wells ◽  
Geothermal Well ◽  
Production Wells ◽  
Geothermal Wells

AbstractThe water temperature at the outlet of the production well is an important index for evaluating efficient geothermal exploration. The arrangement mode of injection wells and production wells directly affects the temperature distribution of the production wells. However, there is little information about the effect of different injection and production wells on the temperature field of production wells and rock mass, so it is critical to solve this problem. To study the influence mechanism of geothermal well arrangement mode on thermal exploration efficiency, the conceptual model of four geothermal wells is constructed by using discrete element software, and the influence law of different arrangement modes of four geothermal wells on rock mass temperature distribution is calculated and analyzed. The results indicated that the maximum water temperature at the outlet of the production well was 84.0 °C due to the thermal superposition effect of the rock mass between the adjacent injection wells and between the adjacent production wells. Inversely, the minimum water temperature at the outlet of the production well was 50.4 °C, which was determined by the convection heat transfer between the water flow and the rock between the interval injection wells and the interval production wells. When the position of the model injection well and production well was adjusted, the isothermal number line of rock mass was almost the same in value, but the direction of water flow and heat transfer was opposite. The study presented a novel mathematical modeling approach for calculating thermal exploration efficiency under various geothermal well layout conditions.

scholarly journals Study On Optimization Mechanism of Thermal Recovery Efficiency Under Different Geothermal Well Layout Conditions

2021 ◽  
Author(s):  
Jun-yi Gao
Keyword(s):  
Temperature Field ◽  
Rock Mass ◽  
Water Temperature ◽  
Working Condition ◽  
Thermal Recovery ◽  
Recovery Efficiency ◽  
Production Well ◽  
Injection Wells ◽  
Production Wells ◽  
Geothermal Wells

Abstract Efficient exploitation of geothermal energy is a hot issue concerned by scientific and engineering circles. The layout of different injection wells and production wells directly affects the temperature field of production wells and rock mass. In order to study the thermal recovery efficiency under different geothermal well layout conditions, based on the conceptual model of two injection wells and two production wells, a 3DEC program is used to calculate and analyze the influence of the different water inlet and water inlet of two injection wells and two production wells on the temperature field of rock mass, geothermal wells and the water temperature of production wells outlet. The results show that: (1) After the model injection wells are switched with the production wells, the temperature gradients of rock mass, production wells and injection wells are almost the same in numerical value and opposite in direction. (2) Production wells are set on the left side and injection wells are set on the right side of the model, and the injection wells and production wells are set at intervals; The temperature field of rock mass on both sides of the edge forms a central symmetry; The temperature gradient of rock mass from the middle to the edge is smaller and smaller, which indicates that the heat transfer speed of rock mass from the middle to the edge is slower and slower. Because the thermal superposition of adjacent injection wells and production wells through the rock mass between them is dominant, the water temperature at the outlet of production wells is the highest; In the interval water injection well and production well, the heat convection between water flow and rock is dominant, which makes the water temperature of production well outlet drops. (3) According to the water temperature at the outlet of production well, the optimal order of the model is working condition 3 > working condition 1 = working condition 2 > working condition 4, and the time to reach a steady state is the shortest in working condition 3 and the longest in working condition 4. The research results can provide important theoretical and practical reference for optimizing the layout of geothermal wells in efficient geothermal exploitation.

scholarly journals Experimental Investigation on Injection and Production Pattern in Fractured-Vuggy Carbonate Reservoirs

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 603
Author(s):  
Juan He ◽  
Aowei Li ◽  
Shanshan Wu ◽  
Ruixue Tang ◽  
Dongliang Lv ◽  
...  
Keyword(s):  
Production Management ◽  
Flow Channel ◽  
Water Flooding ◽  
Production Well ◽  
New Production ◽  
Injection Wells ◽  
Gravity Segregation ◽  
Production Wells ◽  
Oil Water ◽  
Production Pattern

To constitute and adjust the injection and production pattern in fractured-vuggy reservoirs, we extracted twelve fractured-cave structures, fabricated them into physical models with acrylic plates, and performed experiments via these models. The results show that utilizing oil/water gravity segregation sufficiently and forming valid flow channels should be emphasized. Preferentially exploiting the reservoir body containing intermediate-scaled or large-scaled caves, arranging injection wells in fractures or small-scaled caves while placing production wells in large-scaled caves, and separately putting injection wells and production wells in low/high parts of an intermediate-scaled or large-scaled cave, were found to benefit oil/water gravity segregation and thus gain a better water flooding effect in these experiments. Experiments with combined models also figured out that, after adjusting the injection and production pattern, the valid flow channel newly formed must pass through caves containing enough residual oil to improve the water flooding effect and could be obtained by shutting down the old production well while adding a new production well, adding a new production well, or switching the production well into an injection well while adding a new production well. In the actual field, adjusting the well location and altering the flow channel were proposed to conduct together. This study may provide references on the production management of analogous reservoirs.

scholarly journals Research on Design Method for Optimal Flow Rate of U-shaped Geothermal Well Based on Exergy Analysis

2021 ◽  
pp. 014459872110663
Author(s):  
Dong Xiao ◽  
Jiaxin Xu ◽  
Tianduoyi Wang ◽  
Chun Cai ◽  
Li Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Parameter Optimization ◽  
Flow Rate ◽  
Exergy Analysis ◽  
Design Method ◽  
Process Parameter ◽  
Process Parameter Optimization ◽  
Geothermal Well ◽  
Optimal Flow ◽  
Geothermal Wells

Closed-loop U-shaped geothermal wells show great potential owing to their special well-depth structure, which can provide a good flow rate and heat extraction. However, no advanced process parameter optimization method is available for U-shaped geothermal wells. To effectively describe the heat transfer processes of U-shaped geothermal wells, an analytical solution that couples transient heat conduction in the surrounding soil (or rocks) with the quasisteady heat transfer process in boreholes was developed. This modelling approach depends on many common elements, such as the thermophysical properties of the working fluid and series of resistances for various elements in the wellbore. Subsequently, based on the exergy analysis method, the optimal operating flow rate was defined and a design method for the optimal flow rate was developed. Results indicate that to obtain the maximum exergy efficiency, different optimal flow rates for the U-shaped geothermal well are achieved at different stages of the heating period. This findings of this study expand the research ideas of the process parameter optimization of U-shaped geothermal wells and provide a theoretical basis for developing an optimal circulating-flow-rate design for U-shaped geothermal wells.

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