A coupled thermal-hydraulic-mechanical modeling and evaluation of geothermal extraction in the enhanced geothermal system based on analytic hierarchy process and fuzzy comprehensive evaluation

Abstract In the paper, the thermal-hydraulic-mechanical (THM) coupling model is improved by considering more factors, and a comprehensive evaluation method is proposed to optimize the heat extraction way. The thermal extraction characteristics in the Enhanced Geothermal System (EGS) and their influence factors were modeled by several researchers, and various evaluation and optimization methods were established. However, by comparing various thermal-hydraulic-mechanical (THM) models, we find that these factors of THM models are not considered comprehensively, and current EGS evaluation focuses on the individual index, the multi-objective evaluation index system of EGS has not been proposed, and a comprehensive evaluation system considering multiple indexes has not been established yet. In this study, a thermal-hydraulic-mechanical coupling model, considering matrix, fractures and changes in physical parameters of rock and fluid, was established for optimizing the EGS. The evaluation index system, including the operation life, the thermal breakthrough time, the average heat production rate, the total heat recovery factor and the re-injection factor, were presented. And the comprehensive optimization method based on analytic hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE) of EGS were proposed. The model is verified by two analytical solutions. Moreover, the model was solved by finite element method (FEM) to optimize various programs of developing the EGS. In this paper, the performances of different geothermal extraction methods are compared and the different extraction parameters are optimized. The results show that the optimized geothermal mining method has better effect than that before optimization. The orthogonal test shows the optimal case of 5 fractures, the fracture permeability of 10D, the well spacing is 400 m and the production pressure draw-down of 20 MPa. The research results provide an accurate and effective method to optimize the development mode of geothermal resources, which is conductive to improve the geothermal energy efficiency.

[1]  Chaoshui Xu,et al.  A simplified coupled hydro-thermal model for enhanced geothermal systems , 2015 .

[2]  M. Deo,et al.  Effect of different flow schemes on heat recovery from Enhanced Geothermal Systems (EGS) , 2019, Energy.

[3]  César R. Chamorro,et al.  Enhanced geothermal systems in Europe: An estimation and comparison of the technical and sustainable potentials , 2014 .

[4]  Shiwei Yu,et al.  A comprehensive evaluation of the development and utilization of China's regional renewable energy , 2019, Energy Policy.

[5]  P. Dobson,et al.  The Northwest Geysers EGS Demonstration Project, California: Part 1: Characterization and reservoir response to injection , 2016 .

[6]  Yang Li,et al.  Numerical simulation of the heat extraction in 3D-EGS with thermal-hydraulic-mechanical coupling method based on discrete fractures model , 2018, Geothermics.

[7]  Sharad Kelkar,et al.  A coupled thermo-hydro-mechanical modeling of fracture aperture alteration and reservoir deformation during heat extraction from a geothermal reservoir , 2017 .

[8]  X. Jia,et al.  Parametric study of the production performance of an enhanced geothermal system: A case study at the Qiabuqia geothermal area, northeast Tibetan plateau , 2019, Renewable Energy.

[9]  Zhenhua Rui,et al.  The influence of complicated fluid-rock interactions on the geothermal exploitation in the CO2 plume geothermal system , 2017, Applied Energy.

[10]  Tiankui Guo,et al.  Performance of enhanced geothermal system (EGS) in fractured geothermal reservoirs with CO2 as working fluid , 2019, Applied Thermal Engineering.

[11]  Xi Zhang,et al.  A simplified model for heat extraction by circulating fluid through a closed-loop multiple-fracture enhanced geothermal system , 2016 .

[12]  M. Dusseault,et al.  A comprehensive study of geothermal heating and cooling systems , 2019, Sustainable Cities and Society.

[13]  Zhenhua Rui,et al.  Evaluation of Acid Fracturing Treatments in Shale Formation , 2017 .

[14]  Wei Zhang,et al.  Influence of different fracture morphology on heat mining performance of enhanced geothermal systems based on COMSOL , 2017 .

[15]  B. Liu,et al.  Numerical manifold method for thermal–hydraulic coupling in fractured enhance geothermal system , 2019, Engineering Analysis with Boundary Elements.

[16]  Joseph N. Moore,et al.  Efficient workflow for simulation of multifractured enhanced geothermal systems (EGS) , 2019, Renewable Energy.

[17]  R. Weijermars,et al.  Economic appraisal and scoping of geothermal energy extraction projects using depleted hydrocarbon wells , 2018, Energy Strategy Reviews.

[18]  H. Lauwerier.  The transport of heat in an oil layer caused by the injection of hot fluid , 1955 .

[19]  J. Chun,et al.  A comprehensive investigation on performance of oil and gas development in Nigeria: Technical and non-technical analyses , 2018, Energy.

[20]  L. Pająk,et al.  Modelling geothermal and operating parameters of EGS installations in the lower triassic sedimentary formations of the central Poland area , 2015 .

[21]  Tayfun Babadagli,et al.  Potential for enhanced geothermal systems in Alberta, Canada , 2014 .

[22]  Wancheng Zhu,et al.  A Coupled Thermal–Hydrological–Mechanical Damage Model and Its Numerical Simulations of Damage Evolution in APSE , 2016, Materials.

[23]  Zhixue Sun,et al.  Numerical simulation of the heat extraction in EGS with thermal-hydraulic-mechanical coupling method based on discrete fractures model , 2017 .

[24]  W. Jiyang.  Estimate of Geothermal Resources Potential for Hot Dry Rock in the Continental Area of China , 2012 .

[25]  Shicheng Zhang,et al.  A new method for evaluation of fracture network formation capacity of rock , 2015 .

[26]  Yanjun Zhang,et al.  Electricity generation from a three-horizontal-well enhanced geothermal system in the Qiabuqia geothermal field, China: Slickwater fracturing treatments for different reservoir scenarios , 2020 .

[27]  C. Ehlig-Economides,et al.  Comprehensive before-closure model and analysis for fracture calibration injection falloff test , 2019, Journal of Petroleum Science and Engineering.

[28]  Chen Biguan,et al.  A NUMERICAL METHOD FOR DISCRETE FRACTURE NETWORK MODEL FOR FLOW AND HEAT TRANSFER IN TWO-DIMENSIONAL FRACTURED ROCKS , 2014 .

[29]  Yanjun Zhang,et al.  Electricity generation and heating potential from enhanced geothermal system in Songliao Basin, China: Different reservoir stimulation strategies for tight rock and naturally fractured formations , 2015 .

[30]  A.P.S. Selvadurai,et al.  Thermo-hydro-mechanical response of granite to temperature changes , 2014, Environmental Earth Sciences.

[31]  Tianfu Xu,et al.  Optimization of heat extraction strategies in fault-controlled hydro-geothermal reservoirs , 2018, Energy.

[32]  Zhenhua Rui,et al.  Influence of gravel on the propagation pattern of hydraulic fracture in the glutenite reservoir , 2018, Journal of Petroleum Science and Engineering.

[33]  R. Hazlett,et al.  An integrated technical-economic model for evaluating CO2 enhanced oil recovery development , 2019, Applied Energy.

[34]  A. Banerjee,et al.  Evaluation of possibilities in geothermal energy extraction from oceanic crust using offshore wind turbine monopiles , 2018, Renewable and Sustainable Energy Reviews.

[35]  Yangsheng Zhao,et al.  THM (Thermo-hydro-mechanical) coupled mathematical model of fractured media and numerical simulation of a 3D enhanced geothermal system at 573 K and buried depth 6000–7000 M , 2015 .

[36]  Ahmad Ghassemi,et al.  A transient fictitious stress boundary element method for porothermoelastic media , 2004 .

[37]  Tang Chun-an,et al.  Coupled thermal-hydraulic-mechanical model during rock damage and its preliminary application , 2009 .

[38]  Quan Gan,et al.  Production optimization in fractured geothermal reservoirs by coupled discrete fracture network modeling , 2016 .