Case05 Contact normal flow conductivity as a function of depth

 

The initial data file for the project is: Cont_002\Case05\Data\Cont_002_Case05.dat.  

 

The basic datafile definition is very similar to the previous cases. In this case the contact normal flow conductivity is defined as a function of depth. Hence minimal stratigraphy data identifying top surface need to be included. Note that in this case fault angle has been increased so that the fault has depths ranging from 500m to 3500m thus facilitating demonstration of model usage.

 

For more information about contact mechanics see Overview of Contact in ParaGeo and for contact data definition see Contact Data.

 

Contact_property

Data File

 

 

* Contact_property                  NUM=1

! ----------------------------------------

 Name                           "Sand_contact"

 Compression_model                           1

 Compression_properties IDM=1

  /Normal Penalty/                       5000

 Tangential_model                            2

 Tangential_properties IDM=2

  /Tangential Penalty/                     10

  /Friction coefficient/                  0.1

 Flow_model_normal                           3

 Flow_normal_table IDM=4  JDM=3

  /"Depth"/                       0.0          2500         2501         4000        

  /"Fluid Cond. (Contact)"/     3.15E+03     3.15E+03     3.15E-06     3.15E-06    

  /"Fluid Cond. (Filter Cake)"/  3.15E+03     3.15E+03     3.15E-06     3.15E-06    

 Flow_model_tangential                1

 Flow_properties_tangential IDM=1    

  /"Fluid Cond."/                 3.15E+3    

 Thermal_model_normal                        1

 Thermal_properties_normal IDM=2

  /Therm. Cond. (Penalty)/        12.6144E+13

  /Therm. Cond. (Filter Cake)/    12.6144E+13

 Contact_width                           0.001            

 

 

1The Flow_model_normal is set to 3 (fluid conductivity as a function of depth).

2The flow normal model requires definition of Flow_normal_table whereby the normal contact flow conductivities for both fracture and filter cake (fault gouge) are defined as a function of depth in a tabular form. The chosen values have been arbitrarily selected so that the deepest 1500m of the fault is non-conductive whereas the shallowest 2500m of the fault is highly conductive.

 

 

 

 

Stratigraphy data

Data File

 

 

* Stratigraphy_definition

! ---------------------------------

 Top_surface_horizon       "Top"

 

 

* Stratigraphy_horizon  NUM=1

! ---------------------------------

 Name              "Top_surface"

 Geometry_set             "Top"        

 

1Minimal stratigraphy data to identify the top surface is required in order to allow depth dependent data.

 

 

 

 

Results

 

The results for the project are in: Cont_002\Case05\Results.

 

In the results below it can be seen that the high normal conductivities of the shallowest 2500m of the fault facilitated rapid transfer of pore pressure to the fault hanging wall part of the formation.

 

Cont_002_case05_01

Pore pressure contours and fault normal flow conductivity at two simulation times.  Flow velocity vectors show flow crossing the fault at the upper 2500m sections of the fault with the high normal flow conductivities.