Effect of pore pressure gradient on fracture initiation in fluid saturated porous media: Rock

2008 ◽  
Vol 75 (7) ◽  
pp. 1753-1762 ◽  
Author(s):  
Takatoshi Ito
Keyword(s):  
Porous Media ◽  
Pressure Gradient ◽  
Pore Pressure ◽  
Fracture Initiation ◽  
Saturated Porous Media ◽  
Fluid Saturated Porous Media ◽  
Pore Pressure Gradient

Natural Convective Boundary-Layer on Two-Dimensional and Axisymmetric Surfaces in High-Pr Fluids or in Fluid-Saturated Porous Media

1981 ◽  
Vol 103 (4) ◽  
pp. 803-807 ◽  
Author(s):  
R. H. Nilson
Keyword(s):  
Boundary Layer ◽  
Porous Media ◽  
Pressure Gradient ◽  
Normal Component ◽  
Local Geometry ◽  
Saturated Porous Media ◽  
Two Dimensional ◽  
Convective Boundary ◽  
Surface Normal ◽  
Fluid Saturated Porous Media

In natural convective boundary layers on inclined surfaces, the surface-normal component of the buoyancy force induces a pressure gradient across the boundary layer. For the class of flows in which inertial effects are unimportant (including flows at high Prandtl number as well as flow through fluid-saturated porous media), a local nonsimilarity analysis indicates that the effects of the surface-normal pressure gradient on the temperature profile can be characterized by a single local configuration-parameter which depends on the local geometry and on the Rayleigh Number. Under Mangler’s transformation the reported computational results become applicable to axisymmetric as well as two-dimensional geometries of arbitrary contour. In contrast to the single-parameter dependence of the temperature profiles, the velocity profiles depend upon two local geometric parameters, as illustrated for the example of an inclined flat plate.

scholarly journals Numerical simulation on the effect of pore pressure gradient on the rules of hydraulic fracture propagation

2021 ◽  
pp. 014459872110093
Author(s):  
Weiyong Lu ◽  
Changchun He
Keyword(s):  
Pressure Gradient ◽  
Pore Pressure ◽  
Hydraulic Fracture ◽  
Fracture Propagation ◽  
Fracture Initiation ◽  
Hydraulic Fractures ◽  
Initiation And Propagation ◽  
Hydraulic Fracture Propagation ◽  
Pore Pressure Gradient ◽  
Stress Damage

To clarify the influence of pore pressure gradient on hydraulic fracture propagation, the stress distribution in and around the borehole is explained by theoretical analysis method in this paper. A mechanical model of hydraulic fracture initiation under the action of pore pressure gradient is established. Then coupled seepage-stress-damage software is used to simulate the initiation and propagation of hydraulic fractures in rock samples under the action of pore pressure gradient. Finally, the influence of the number and spatial position of the induction holes on the initiation and propagation of hydraulic fractures is analyzed. It is shown that: (1) Pore pressure gradient can effectively reduce the initiation pressure of hydraulic fractures. (2) The greater the pore pressure gradient is, the easier the hydraulic fracture is to spread to the region with high pore pressure. (3) With the action of pore pressure gradient, the hydraulic fracture is shaped as ‘丨’, ‘丿’ and ‘S’ types and can be represented by the four abstract conceptual models.

Semi-analytical finite element method for simulating chemical dissolution-front instability problems in fluid-saturated porous media

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chongbin Zhao ◽  
B.E. Hobbs ◽  
Alison Ord
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Porous Media ◽  
Chemical Dissolution ◽  
Saturated Porous Media ◽  
Content Type ◽  
Front Instability ◽  
Fluid Saturated Porous Media ◽  
Dissolution Front ◽  
Element Method

PurposeThe objective of this paper is to develop a semi-analytical finite element method for solving chemical dissolution-front instability problems in fluid-saturated porous media.Design/methodology/approachThe porosity, horizontal and vertical components of the pore-fluid velocity and solute concentration are selected as four fundamental unknown variables for describing chemical dissolution-front instability problems in fluid-saturated porous media. To avoid the use of numerical integration, analytical solutions for the property matrices of a rectangular element are precisely derived in a purely mathematical manner. This means that the proposed finite element method is a kind of semi-analytical method. The column pivot element solver is used to solve the resulting finite element equations of the chemical dissolution-front instability problem.FindingsThe direct use of horizontal and vertical components of the pore-fluid velocity as fundamental unknown variables can improve the accuracy of the related numerical solution. The column pivot element solver is useful for solving the finite element equations of a chemical dissolution-front instability problem. The proposed semi-analytical finite element method can produce highly accurate numerical solutions for simulating chemical dissolution-front instability problems in fluid-saturated porous media.Originality/valueAnalytical solutions for the property matrices of a rectangular element are precisely derived for solving chemical dissolution-front instability problems in fluid-saturated porous media. The proposed semi-analytical finite element method provides a useful way for understanding the underlying dynamic mechanisms of the washing land method involved in the contaminated land remediation.

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