Parameter_data

 

Data Structure: Parameter_data

Description

Input/output files

Usage

Parameter_data     NUM=ival   where ival  is the data structure number

 

Description

Overview

The Parameter_data data structure defines the parameters (variables) and parameter ranges to be considered in the inversion analysis.

 

The inversion paramters may be identified in the data files by either:

•Direct specification of the associated material or fluid data structure ( ParaGeo Only). In this case the data structure type and number must be specified for each parameter using Variable_structure_name and Variable_structure_number

•Replacing the parameter value with < p> ParameterName < p> in the template data file where ParameterName is an arbitrary name assigned to such parameter.

 

 

Click to expand/collapseName    Parameter names

Usage

Name

IDM=ival

 

 

Character Names

 

 

 

 

where

ival

Number of parameters to be evaluated in the inversion

Description

List of parameter names to be considered in the present inversion analysis. If the parameters are identified in the template data file via < p> ParameterName < p> then the parameter names can be arbitrarily defined and here ParameterName needs to be specified. For inversion using ParaGeo material parameters the list of valid names is:

 

Elasticity

Name

Description

Young

Young's Modulus

Poiss

Poisson's ratio

 

Porosity

Name

Description

Porosity

Porosity

Porosity_gradient

Linear gradient of porosity with pore pressure

 

Permeability

Name

Description

Permeability

Isotropic permeabiltiy

Permeability_x

Orthotropic permeabiltiy in X-direction

Permeability_y

Orthotropic permeabiltiy in Y-direction

Permeability_z

Orthotropic permeabiltiy in Z-direction

Permeability_gradient

Isotropic permeabiltiy gradient with pore pressure

 

Tortuosity

Name

Description

Tortuosity

Tortuosity

Tortuosity_gradient

Linear gradient of tortuosity with pore pressure

 

For inversion of fluid properties valid parameters are:

 

Viscosity

Name

Description

Viscosity

Viscosity

Viscosity_gradient

Linear gradient of viscosity with pore pressure

 

Knudsen Diffusion

Name

Description

Klinkenberg_b

Klinkenberg b coefficient

Beskok_alpha

Constant alpha in Beskok and Karniadakis model

Beskok_a_con

Constant A in Beskok and Karniadakis model

Beskok_b_con

Constant B in Beskok and Karniadakis model

Beskok_b

Constant b in Beskok and Karniadakis model (not same as Klinkenberg b

 

 

For inversion of fracture properties valid parameters are:

 

Fracture Normal stiffness

Name

Description

Fracture_spacing

Fracture spacing

Norm_stiffness

Normal stiffness

Init_norm_stiff

Initial normal stiffness

Init_aperture

Initial aperture

Max_norm_stiff

Maximum normal stiffness

 

Fracture Shear Stiffness

Name

Description

Shear_stiffness

Normal stiffness

Shear_stiff_fact

Factor of normal stiffness defining shear stiffness

Max_shear_stiff

Maximum shear stiffness

Max_shear_stress

Maximum shear stress

 

Fracture Hydraulic fracture

Name

Description

Minimum_stress

Minimum stresss corresponding to hydrofracture initiation

Percent_pore

Percentage of pore pressure corresponding to hydrofracture initiation

 

Fracture Shear Strength

Name

Description

Cohesion

Cohesion

Frict_angle

Friction angle

Res_cohesion

Residual Cohesion

Res_shear_disp

Shear displacement at residual values

 

Fracture Reference Values

Name

Description

Ref_norm_stress

Reference Normal Stress

Ref_shear_xz

Reference Shear Stress-XZ

Ref_shear_yz

Reference Shear Stress-YZ

 

 

Click to expand/collapseType    Type of parameter

Usage

Type

IDM=ival

 

 

Integer Values

 

 

 

 

where

ival

Number of parameters to be evaluated in the inversion

Description

Defines the type of parameter for each of the parameters defined via Name keyword. Valid options are:

•0 - free (to be evaluated during the inversion with values set within the input range via the Minimum_value and Maximum_value keywords)

•1 - prescribed (fixed value using the Value keyword)

 

Notes

 

Click to expand/collapseValue    Value of prescribed parameters

Usage

Value

IDM=ival

 

 

Real Values

 

 

 

 

where

ival

Number of parameters to be evaluated in the inversion

Description

Value keyword is used to define values for the prescribed parameters (those assigned Type = 1). Note that if Value keyword is defined a value must be input for each parameter listed via Name keyword with the values for the free parameters being ignored.

 

Notes

•If all parameters are free then Value does not need to be specified.

 

 

Click to expand/collapseMinimum_value    Minimum value of free parameters

Usage

Minimum_value

IDM=ival

 

 

Real Values

 

 

 

 

where

ival

Number of parameters to be evaluated in the inversion

Description

Minimum_value keyword is used to define the minimum allowed value for free parameters (those defined with Type = 0) in the models generated during the inversion analysis. Minimum_value keyword must always be defined and a value must be input for each parameter listed in Name keyword with the values for fixed parameters being ignored.

 

 

Click to expand/collapseMaximum_value    Maximum value of free parameters

Usage

Maximum_value

IDM=ival

 

 

Real Values

 

 

 

 

where

ival

Number of parameters to be evaluated in the inversion

Description

Maximum_value keyword is used to define the maximum allowed value for free parameters (those defined with Type = 0) in the models generated during the inversion analysis. Maximum_value keyword must always be defined and a value must be input for each parameter listed in Name keyword with the values for fixed parameters being ignored.

 

 

Click to expand/collapseVariable_structure_name    Data structure associated with each parameter

Usage

Variable_structure_name

IDM=ival

 

 

Character Names

 

 

 

 

where

ival

Number of parameters to be evaluated in the inversion

Description

The Variable_structure_name keyword is used to identify the ParaGeo data structure name containing each of the parameters listed in Name keyword. Currently parameters for inversion can only belong to Material_data or Fluid_properties data structures or they may be inversion parameters defined via usage of < p> ParameterName < p> in the template data file. Then the Variable_structure_name for those must be defined with the ParameterName.

 

Notes

•By default all variables are assumed to be of type < p> ParameterName < p> defined in the template file. Consequently, if all variables are of such type then Variable_structure_name is not required (keyword Name will be sufficient to identify the inversion parameters names).

 

 

Click to expand/collapseVariable_structure_number    Data structure number associated with a parameter

Usage

Variable_structure_number

IDM=ival

 

 

Integer Values

 

 

 

 

where

ival

Number of parameters to be evaluated in the inversion

Description

The Variable_structure_number keyword is used to identify the ParaGeo data structure number corresponding to each Variable_structure_name in order to fully identify the location of a given inversion (e.g. there may be two Material_data structures defined but a given inversion parameter will belong only to one of those which needs to be identified with the Variable_structure_name and Variable_structure_number ). Variable_structre_number is compulsory if Variable_structure_name is used.

Currently parameters for inversion can only belong to Material_data or Fluid_properties data structures or they may be inversion parameters defined via usage of < p > ParameterName < p > in the template data file. Then the Variable_structure_number for those must be set to 0.

 

Notes

•If all variables are defined via < p> ParameterName < p> then neither Variable_structure_name nor Variable_structure_number are required.