scholarly journals A New Approach to Hydraulic Stimulation of Geothermal Reservoirs by Roughness Induced Fracture Opening

10.5772/56447 ◽  
2013 ◽  
Author(s):  
Nima Gholizadeh ◽  
Sheik S. ◽  
Andrei Kotousov
Keyword(s):  
Hydraulic Stimulation ◽  
New Approach ◽  
Geothermal Reservoirs ◽  
Fracture Opening ◽  
Stimulation Of

scholarly journals Fault slip in hydraulic stimulation of geothermal reservoirs: Governing mechanisms and process-structure interaction

2020 ◽  
Vol 39 (12) ◽  
pp. 893-900
Author(s):  
Inga Berre ◽  
Ivar Stefansson ◽  
Eirik Keilegavlen
Keyword(s):  
Fault Reactivation ◽  
Fluid Injection ◽  
Hydraulic Stimulation ◽  
Structure Interaction ◽  
Geothermal Reservoirs ◽  
Biot Coefficient ◽  
Matrix Permeability ◽  
Stress Changes ◽  
Process Structure ◽  
Stimulation Of

Hydraulic stimulation of geothermal reservoirs in low-permeability basement and crystalline igneous rock can enhance permeability by reactivation and shear dilation of existing fractures. The process is characterized by interaction between fluid flow, deformation, and the fractured structure of the formation. The flow is highly affected by the fracture network, which in turn is deformed because of hydromechanical stress changes caused by the fluid injection. This process-structure interaction is decisive for the outcome of hydraulic stimulation, and, in analysis of governing mechanisms, physics-based modeling has potential to complement field and experimental data. Here, we show how recently developed simulation technology is a valuable tool to understand governing mechanisms of hydromechanical coupled processes and the reactivation and deformation of faults. The methodology fully couples flow in faults and matrix with poroelastic matrix deformation and a contact mechanics model for the faults, including dilation because of slip. Key elements are high aspect ratios of faults and strong nonlinearities in highly coupled governing equations. Example simulations using our open-source software illustrate direct and indirect hydraulic fault reactivation and corresponding permeability enhancement. We investigate the effect of the fault and matrix permeability and the Biot coefficient. A higher matrix permeability leads to more leakage from a permeable fault and thus suppresses reactivation and slip of the fault compared to the case with a lower matrix permeability. If a fault is a barrier to flow, increase of pressure because of the fluid injection results in stabilization of the fault; the situation is opposite if the fault is highly permeable compared to the matrix. For the given setup, lowering the Biot coefficient results in more slip than the base case. While conceptually simple, the examples illustrate the strong hydromechanical couplings and the prospects of physics-based numerical models in investigating the dynamics.

Hydraulic stimulation of geothermal wells

2011 ◽  
pp. 1309-1314 ◽  
Author(s):  
S Gentier ◽  
X Rachez ◽  
M Peter-Borie ◽  
A Blaisonneau
Keyword(s):  
Hydraulic Stimulation ◽  
Geothermal Wells ◽  
Stimulation Of

Kinematic dilation during the hydraulic stimulation of pre-fractured rocks

2019 ◽  
Vol 9 (3) ◽  
pp. 186-192 ◽  
Author(s):  
S. Roshankhah ◽  
L. G. Cruz ◽  
H. Shin ◽  
A. Lizcano ◽  
J. C. Santamarina
Keyword(s):  
Fractured Rocks ◽  
Hydraulic Stimulation ◽  
Stimulation Of

scholarly journals Modulation of gut mucosal biofilms

2005 ◽  
Vol 93 (S1) ◽  
pp. S35-S40 ◽  
Author(s):  
Brigitta Kleessen ◽  
Michael Blaut
Keyword(s):  
Colonic Mucosa ◽  
Mucosal Barrier ◽  
Mucus Layer ◽  
Faecal Flora ◽  
New Approach ◽  
Serovar Typhimurium ◽  
Health Promoting ◽  
Gut Mucosal Barrier ◽  
Induced Changes ◽  
Stimulation Of

Non-digestible inulin-type fructans, such as oligofructose and high-molecular-weight inulin, have been shown to have the ability to alter the intestinal microbiota composition in such a way that members of the microbial community, generally considered as health-promoting, are stimulated. Bifidobacteria and lactobacilli are the most frequently targeted organisms. Less information exists on effects of inulin-type fructans on the composition, metabolism and healthrelated significance of bacteria at or near the mucosa surface or in the mucus layer forming mucosa-associated biofilms. Using rats inoculated with a human faecal flora as an experimental model we have found that inulin-type fructans in the diet modulated the gut microbiota by stimulation of mucosa-associated bifidobacteria as well as by partial reduction of pathogenicSalmonella enterica subsp. entericaserovar Typhimurium and thereby benefit health. In addition to changes in mucosal biofilms, inulin-type fructans also induced changes in the colonic mucosa stimulating proliferation in the crypts, increasing the release of mucins, and altering the profile of mucin components in the goblet cells and epithelial mucus layer. These results indicate that inulin-type fructans may stabilise the gut mucosal barrier. Dietary supplementation with these prebiotics could offer a new approach to supporting the barrier function of the mucosa.

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