Unified pipe network method for simulation of water flow in fractured porous rock

2017 ◽  
Vol 547 ◽  
pp. 80-96 ◽  
Author(s):  
Feng Ren ◽  
Guowei Ma ◽  
Yang Wang ◽  
Tuo Li ◽  
Hehua Zhu
Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1122 ◽  
Author(s):  
Zizheng Sun ◽  
Xiao Yan ◽  
Rentai Liu ◽  
Zhenhao Xu ◽  
Shucai Li ◽  
...  

Grouting is widely used for mitigating the seepage of underground water and enhancing the stability of fractured rock mass. After injection, the viscosity of the grout gradually increases until solidification. Conventional multifield analysis models ignoring such effects greatly overestimate the penetration region of the grout and the stability of the grouted rock structures. Based on the 3D unified pipe-network method (UPM), we propose a novel numerical model considering the time-dependent viscosity of the grout, therein being a quasi-implicit approach of high efficiency. The proposed model is verified by comparing with analytical results and a time-wise method. Several large-scale 3D examples of fractured rock mass are considered in the numerical studies, demonstrating the effectiveness and robustness of the proposed method. The influence of the time-dependent viscosity, fracture properties, and grouting operation methods are discussed for the grout penetration process.


Processes ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 46 ◽  
Author(s):  
Zizheng Sun ◽  
Xiao Yan ◽  
Weiqi Han ◽  
Guowei Ma ◽  
Yiming Zhang

In grouting process, filtration is the retention and adsorption of cement-grout particles in a porous/fractured medium. Filtration partly/even completely blocks the transportation channels in the medium, greatly decreasing its permeability. Taking into account filtration effects is essential for accurately estimating the grout penetration region. In this paper, the 3D unified pipe-network method (UPM) is adopted for simulating 3D grout penetration process in a fractured porous medium, considering filtration effects. The grout is assumed to exhibit two-phase flow, and the filtration effects depend on not only the concentration and rheology of the grout but also the porosity and permeability of the fractured porous medium. By comparing the model with the experimental results, we firstly verify the proposed numerical model. Then sensitivity analysis is conducted, showing the influences of grout injection pressures, the water–cement ratios of grout (W/C) and the grout injection rates on filtration effect. Finally, the grout filtration process in a complex 3D fractured network is simulated, indicating that the size of the grout penetration region is limited due to filtration.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 387
Author(s):  
Xiao Yan ◽  
Zizheng Sun ◽  
Shucai Li ◽  
Weimin Yang ◽  
Yiming Zhang

In this paper, we first recapitulate some basic notions of the CO 2 sequestration and numerical model. Next, a mixed model is employed into the CO 2 sequestration framework, for simulating CO 2 geological sequestration processes. The last part of the paper makes extensions to evaluation of the effectiveness of CO 2 sequestration with respect to atmospheric pressure, formation temperature, the initial reactant concentration, fracture aperture, and fracture dip. The results show that reactive Portland cement has a great impact on the effectiveness of CO 2 sequestration, while the proposed mixed model is robust in simulation.


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