Simulating cryogenic fracturing process with TOUGH-FEMM

2020 ◽  
Author(s):  
Haiyang Zhao ◽  
Zhiyuan Liu
Keyword(s):  
Thermal Gradient ◽  
Three Dimensional ◽  
Meshfree Method ◽  
Clean Energy ◽  
Fracture Network ◽  
Carbon Production ◽  
Fracturing Process ◽  
Hydro Carbon ◽  
Cryogenic Fracturing ◽  
Hydraulic Simulator

<p>The dry hot rock (DHR) is a widely distributed renewable and clean energy. Cryogenic fracturing, such as liquid nitrogen fracturing technology, in DHR not only avoids the consuming of water, but also enhances the fracturing with the rock damage induced by thermal stress. During fracturing, cryogenic fluid (extremely low temperature) is utilized to trigger sharp a thermal gradient and fracturing surrounding boreholes, which generates fracture networks and increase the permeability of DHR. In this work, the TOUGH-FEMM simulator, which links the TOUGH2 thermal-hydraulic simulator and a mechanical simulator based on hybrid the finite-element meshfree method (FEMM), is developed to model three-dimensional cracking induced by cryogenic injection. The results of the numerical simulations agree with the experimental results showing that the fracture network is generated and connected to the borehole. An increased connectivity between a production borehole and the fracture network can significantly enhance fluid and hydro carbon production.</p>

scholarly journals Numerical simulation on the simultaneous stress interference of parallel multiple hydraulic fractures

2021 ◽  
pp. 014459872110019
Author(s):  
Weiyong Lu ◽  
Changchun He
Keyword(s):  
Principal Stress ◽  
Hydraulic Fracture ◽  
Stress Ratio ◽  
Fracture Network ◽  
Hydraulic Fractures ◽  
Fracture Spacing ◽  
Induced Stress ◽  
Minimum Principal Stress ◽  
Fracturing Process ◽  
Stress Ratios

During horizontal well staged fracturing, there is stress interference between multiple transverse fractures in the same perforation cluster. Theoretical analysis and numerical calculation methods are applied in this study. We analysed the mechanism of induced stress interference in a single fracture under different fracture spacings and principal stress ratios. We also investigated the hydraulic fracture morphology and synchronous expansion process under different fracture spacings and principal stress ratios. The results show that the essence of induced stress is the stress increment in the area around the hydraulic fracture. Induced stress had a dual role in the fracturing process. It created favourable ground stress conditions for the diversion of hydraulic fractures and the formation of complex fracture network systems, inhibited fracture expansion in local areas, stopped hydraulic fractures, and prevented the formation of effective fractures. The curves of the maximum principal stress, minimum principal stress, and induced principal stress difference with distance under different fracture lengths, different fracture spacings, and different principal stress ratios were consistent overall. With a small fracture spacing and a small principal stress ratio, intermediate hydraulic fractures were difficult to initiate or arrest soon after initiation, fractures did not expand easily, and the expansion speed of lateral hydraulic fractures was fast. Moreover, with a smaller fracture spacing and a smaller principal stress ratio, hydraulic fractures were more prone to steering, and even new fractures were produced in the minimum principal stress direction, which was beneficial to the fracture network communication in the reservoir. When the local stress and fracture spacing were appropriate, the intermediate fracture could expand normally, which could effectively increase the reservoir permeability.

scholarly journals Characterizing Reactive Transport Behavior in a Three-Dimensional Discrete Fracture Network

2021 ◽  
Author(s):  
Thomas Sherman ◽  
Guillem Sole-Mari ◽  
Jeffrey Hyman ◽  
Matthew R. Sweeney ◽  
Daniel Vassallo ◽  
...  
Keyword(s):  
Reactive Transport ◽  
Three Dimensional ◽  
Fracture Network ◽  
Discrete Fracture Network ◽  
Transport Behavior ◽  
Discrete Fracture

Backcalculation of Thermally Deformed Concrete Pavements

2000 ◽  
Vol 1716 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Samir N. Shoukry
Keyword(s):  
Thermal Gradient ◽  
Concrete Slab ◽  
Three Dimensional ◽  
Plain Concrete ◽  
Slab Thickness ◽  
Fe Model ◽  
Concrete Pavements ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Falling Weight

Nonlinear explicit three-dimensional finite element (3-D FE) modeling is used to investigate the performance of the falling weight deflectometer (FWD) test in the evaluation of layer moduli of jointed plain concrete pavements (JPCP) subjected to nonlinear thermal gradient through the slab thickness. Concrete slab separation from the base, in-plane friction at the concrete-base interface, the gravitational forces, and the interface characteristics between dowel bars and surrounding concrete are all represented in the 3-D FE model. Experimental verification of the model is obtained through comparison of the 3-D FE generated response to ( a) the FWD measured deflection basin and ( b) the measured response of an instrumented rigid pavement section located in Ohio to a loaded truck moving at 21.8 m/s (48 mph). Several cases of linear and nonlinear thermal gradients are applied to the model, and deflection basins are obtained. Two backcalculation programs, MODULUS 5.0 and EVERCALC 4.0, are used for prediction of the layer moduli in each case, and the values are compared. The results indicate that thermal curling of the slab due to negative thermal gradient has little effect on the accuracy of backcalculated moduli. Warping of the slab due to positive thermal gradient greatly influences the measured FWD deflection basin and leads to significant errors in the backcalculated moduli. These errors may be minimized if the time an FWD test is conducted falls between the late afternoon and midmorning (from 5:30 p.m. to 9:30 a.m. during summer in West Virginia).

A New Method for Three-Dimensional Fracture Network Modelling for Trace Data Collected in a Large Sampling Window

2019 ◽  
Vol 53 (3) ◽  
pp. 1145-1161 ◽  
Author(s):  
Zhenbang Nie ◽  
Jianping Chen ◽  
Wen Zhang ◽  
Chun Tan ◽  
Zhifa Ma ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Fracture Network ◽  
New Method ◽  
Network Modelling ◽  
Trace Data ◽  
Sampling Window

scholarly journals Hybrid Analytical and Numerical Approach for Modeling Fluid Flow in Simplified Three-Dimensional Fracture Networks

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
D. Roubinet ◽  
S. Demirel ◽  
E. B. Voytek ◽  
X. Wang ◽  
J. Irving
Keyword(s):  
Fluid Flow ◽  
Three Dimensional ◽  
Fracture Network ◽  
Numerical Approach ◽  
Fracture Networks ◽  
Surrounding Matrix ◽  
Mesh Free ◽  
Fracture Scale ◽  
The Impact ◽  
Numerical Approaches

Modeling fluid flow in three-dimensional fracture networks is required in a wide variety of applications related to fractured rocks. Numerical approaches developed for this purpose rely on either simplified representations of the physics of the considered problem using mesh-free methods at the fracture scale or complex meshing of the studied systems resulting in considerable computational costs. Here, we derive an alternative approach that does not rely on a full meshing of the fracture network yet maintains an accurate representation of the modeled physical processes. This is done by considering simplified fracture networks in which the fractures are represented as rectangles that are divided into rectangular subfractures such that the fracture intersections are defined on the borders of these subfractures. Two-dimensional analytical solutions for the Darcy-scale flow problem are utilized at the subfracture scale and coupled at the fracture-network scale through discretization nodes located on the subfracture borders. We investigate the impact of parameters related to the location and number of the discretization nodes on the results obtained, and we compare our results with those calculated using reference solutions, which are an analytical solution for simple configurations and a standard finite-element modeling approach for complex configurations. This work represents a first step towards the development of 3D hybrid analytical and numerical approaches where the impact of the surrounding matrix will be eventually considered.

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