Enhanced Geothermal System Model for Flow through a Stimulated Rock Volume

2021 ◽  
Author(s):  
Leila Zeinali ◽  
Christine Ehlig-Economides ◽  
Michael Nikolaou
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Power Plant ◽  
Horizontal Well ◽  
Numerical Models ◽  
Horizontal Wells ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Well Pattern ◽  
Flow Through

Abstract An Enhanced Geothermal System (EGS) uses flow through fractures in an effectively impermeable high-temperature rock formation to provide sustainable and affordable heat extraction that can be employed virtually anywhere with no need for a geothermal reservoir. The problem is that there is no commercial application of this technology. The three-well pattern introduced in this paper employs a multiple transverse fractured horizontal well (MTFHW) drilled and fractured in an effectively impermeable high-temperature formation. Two parallel horizontal wells drilled above and below or on opposing sides of the MTFHW have trajectories that intersect its created fractures. Fluid injected in the MTFHW flows through the fractures and horizontal wells, thus extracting heat from the surrounding high-temperature rock. This study aims to find the most cost-effective well and fracture spacing for this pattern to supply hot fluid to a 20-megawatt power plant. Analytical and numerical models compare heat transfer behavior for a single fracture unit in an MTFHW that is then replicated along with the horizontal well pattern(s). The Computer Modeling Group (CMG) STARS simulator is used to model the circulation of cold water injected into the center of a radial transverse hydraulic fracture and produced from two horizontal wells. Key factors to the design include formation temperature, the flow rate in fractures, the fractured radius, spacing, heat transfer, and pressure loss along the wells. The Aspen HYSYS software is used to model the geothermal power plant, and heat transfer and pressure loss in wells and fractures. The comparison between analytical and numerical models showed the simplified analytical model provides overly optimistic results and indicates the need for a numerical model. Sensitivity studies using the numerical model vary the key design factors and reveal how many fractures the plant requires. The economic performance of several scenarios was investigated to minimize well drilling and completion pattern costs. This study illustrates the viability of applying known and widely used well technologies in an enhanced geothermal system.

The Research of Energy Conversion and Heat Transfer in the Ceramic Foams of Solar Energy Converter

2011 ◽  
Author(s):  
Yangbo Deng ◽  
Fengmin Su ◽  
Chunji Yan
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Solar Radiation ◽  
Solar Energy ◽  
Numerical Models ◽  
Air Flow ◽  
Energy Converter ◽  
Ceramic Foams ◽  
Numerical Studies ◽  
Flow Through

The solar energy converter in Concentrated Solar Power (CSP) system, applies the solid frame structure of the ceramic foams to receive the concentrated solar radiation, convert it into thermal energy, and heat the air flow through the ceramic foams by convection heat transfer. In this paper, first, the pressure drops in the studied ceramic foams were measured under all kinds of flow condition. Based on the experimental results, an empirical numerical model was built for the air flow through ceramic foams. Second, a 3-D numerical model was built, for the receiving and conversion of the solar energy in the ceramic foams of the solar energy converter. Third, applying two aforementioned numerical models, the numerical studies of the thermal performance were carried out, for the solar energy converter filled with the ceramic foams, and results show that the structure parameters of the ceramic foams, the effective reflective area and the solar radiation intensity of the solar concentrator, have direct impacts on the absorptivity and conversion efficiency of the solar energy in the solar energy converter. And the results of the numerical studies are found to be in reasonable agreement with the experimental measurements. This paper will provide a reference for the design and manufacture of the solar energy converter with the ceramic foams.

Depth-dependent analysis of fracture patterns inferred from image logs and cores in crystalline rocks

2020 ◽  
Author(s):  
Mohammad Javad Afshari Moein
Keyword(s):  
Spatial Distribution ◽  
Correlation Dimension ◽  
Numerical Models ◽  
Fracture Network ◽  
Crystalline Rocks ◽  
Geothermal System ◽  
Upper Rhine Graben ◽  
Enhanced Geothermal System ◽  
Fracture Density ◽  
Fracture Patterns

<p>Enhanced Geothermal System (EGS) development requires an accurate fracture network characterization. The knowledge on the fracture network is fundamental for setting up numerical models to simulate the activated processes in hydraulic stimulation experiments. However, direct measurement of fracture network properties at great depth is limited to the data from exploration wells. Geophysical logging techniques and continuous coring, if available, provide the location and orientation of fractures that intersect the wellbore. The statistical parameters derived from borehole datasets (either from image logs or cores) constrain stochastic realizations of the rock mass, known as Discrete Fracture Network (DFN) models. However, accurate parametrization of DFN models requires sufficient knowledge on the depth-dependent spatial distribution of fractures in the earth’s crust.</p><p>This analysis includes a unique collection of fracture datasets from six deep (i.e. 2-5 km depth) boreholes drilled into crystalline basement rocks at the same tectonic settings. All the wells were drilled in the Upper Rhine Graben in Soultz-sous-Forêts Enhanced Geothermal System, France, except the well that was drilled in Basel geothermal project, Switzerland. The datasets included both borehole image logs and core samples, which have a higher resolution. Two-point correlation function was selected to characterize the power-law scaling of fracture patterns. The correlation dimension of spatial patterns showed no systematic variations with depth at one standard deviation level of uncertainty in moving windows of sufficient number of fractures along any of the boreholes. This implies that a single correlation dimension is sufficient to address the global scaling properties of the fractures in crystalline rocks. One could also anticipate the spatial distribution of deeper reservoir conditions from shallower datasets. On the contrary, the fracture density showed some variations with depth that are sometimes consistent with changes in lithology and geological settings at the time of fracture formation.</p>

Mathematical Modeling of Heat Transfer and Pressure Drops in the Single- and Dual-Pipe Horizontal Wells

2016 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaohu Dong ◽  
Huiqing Liu ◽  
Zhangxin Chen
Keyword(s):  
Heat Transfer ◽  
Horizontal Well ◽  
Horizontal Wells ◽  
Steam Injection ◽  
Thermal Recovery ◽  
Pressure Drops ◽  
Injection Process ◽  
Single Pipe ◽  
Productivity Prediction ◽  
Transfer Mechanisms

In this paper, from the heat transfer mechanisms between perforated horizontal well and formation, the mathematical models for the heat transfer and pressure drops of the horizontal well with different steam injection pipe configurations are developed. All the conventional single-pipe, concentric dual-pipe, and parallel dual-pipe configurations are considered. A correlation is proposed to represent a relationship between the thermophysical properties of the formation and the formation pressure and temperature. Then, using the method of wellbore microcontrol elements and node analysis, the steam injection process in the three different well configurations is numerically investigated. Based on the test data of a parallel dual-pipe horizontal well from an actual oilfield, a steam backflow procedure for the parallel dual-pipe configuration is proposed to confirm the sealed status of a thermal packer. The theoretical investigation plays an important role in the performance evaluation and productivity prediction of horizontal well-based thermal recovery projects. Furthermore, it also sheds some important insights on a steam injection project design with dual-pipe horizontal wells.

Experimental Research on Electric Analogy of Staged Fracturing of Horizontal Wells Flooding

2014 ◽  
Vol 955-959 ◽  
pp. 3484-3488
Author(s):  
Guang Zhong Lv ◽  
Jiang Qiao Zhang
Keyword(s):  
Horizontal Well ◽  
Horizontal Wells ◽  
Experimental Conditions ◽  
Horizontal Section ◽  
Fracture Length ◽  
Unidirectional Flow ◽  
Horizontal Length ◽  
Fractured Horizontal Well ◽  
Well Pattern ◽  
Penetration Ratio

An electrolytic simulation experiment was designed according to the water and electricity resembling principle. The pressure contour distribution and the effects of the productivity of the fractured horizontal well were experimentally studied under the flooding. The equal pressure lines around horizontal wells were elliptic, and the equal pressure lines were Parallelled distribution in the fracture of horizontal well, Flow states was unidirectional flow, indicating staged fracturing of horizontal well by improving Percolation way greatly reduce seepage resistance. Under the experimental conditions, staged fracturing horizontal waterflooding development best combination of parameters: row and staggered well pattern, penetration ratio of horizontal section was 0.8, the number of fractures should be 6 (fracture space was 91m), penetration ratio of fracture was 0.25, the angle between the fracture and horizontal well is 90 degree. The importance ranking of productivity was horizontal length, the number of fractures (fracture space ),fracture length, he angle between the fracture and horizontal well and well-pattern type.

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