Two phase flow - GROUPINGS & OUTPUT page

Two phase flow - GROUPINGS

A grouping is a set of faulted cell faces sharing similar properties for which the same up-scaled two phase properties are generated. The Groupings settings control the number of groups that ViewGen attempts to create and the structure of the hierarchy used to create the groups.

A group is defined by 8 model variables:-

FAULT CYCLE (Drainage or Imbibition)

CELL SATNUM (i.e. original cell relative permeability and capillary pressure functions)

FAULT PERMEABILITY (calculated from single-phase TransGen definitions)

FAULT THICKNESS (calculated from single-phase TransGen definitions)

FLOW RATE (imported directly or calculated from cell pressures)

CELL PERMEABILITY (imported)

CELL POROSITY (imported)

CELL LENGTH (calculated from the model geometry)

The cycle of the connection (Drainage or Imbibition) and the SWOF table of the faulted grid-block form the primary definitions of the groups. The number of further divisions can be defined by the user, by defining both the number of divisions to make on the basis of each variable and the priority of the variable in the grouping hierarchy.

A different number of bins may be specified in the drainage and imbibition cycles, but the same parameter priorities are used for both.

Parameter Priorities vary between 1 and 6 with a higher number giving greater priority to a parameter. For instance, if fault permeability is set a Parameter Priority of 6, fault permeability is positioned at the top of the hierarchy and the initial groupings are derived based on this. If three groups are specified for permeability, three sets of faulted connections are constructed based on the permeability values present. The next set of divisions (for the parameter with priority 5) is based on the values of the parameter present in each of the three bins.

At each level in the hierarchy, the values of the next variable are binned based on the maximum and minimum values of the variable present in the previous bin, according to the number of divisions specified. Linear bins are used for fault thickness, cell porosity and cell length. Logarithmic bins are used for flow rate, fault permeability and cell permeability.

The number of flow rate divisions is not allowed to be less than 2. This is because all cell faces with negative flow (i.e. flow is in the opposite direction) are assigned directional relative permeability functions calculated using a zero- flow rate. If less than 2 groupings are specified for flow rate by the user, WizGen issues an error.

Two phase flow - OUTPUT

Two-phase fault-rock properties are implemented in the simulator using directional, irreversible cell properties and TransGen outputs two files which should be included in the simulator to do this. The Two phase flow - OUTPUT settings are to specify the names of these two files, one of which will contain the new (pseudo) relative permeability and capillary tables output in the SWOF keyword (or MoReS compatible) format and the other to contain the "KRNUM" keywords which index the SWOF output into the faulted cells.

NOTE:- Additionally, two constants required by the Eclipse simulator are reported on completion of running 2PhaseGen and in the header of the SWOF file.

The Relative permeability tables and the KRNUM data can be output in either Eclipse, (SWOF keyword) or MoReS compatible format (for Shell users).
Click either the SWOF or the MORES option "on", Browse to the required directory (e.g. the _OUTPUT directory in the current TransGen project), input an appropriate file name and Save the settings to output:-

Relative permeability tables, i.e. a file containing the original and the new (pseudo) relative permeability and capillary tables (see Examples of output files for details).

KRNUM output, i.e. a file containing the KRNUM keywords (KRNUMX, KRNUMX-, KRNUMY, KRNUMY-, KRNUMZ, KRNUMZ-) plus associated indices to link the relative permeability tables output for each cell in the model (see example KRNUM output file for details).

HINT:- The KRNUM output will be created at the end of a ViewGen run and the indices to the tables for KRnumX+, KRnumX-, KRnumY+ or KRnumY- can be displayed as cell properties in ViewGen.

When the Two phase flow - page 3 is set as required, click on the Next >> button to view the current settings in the Project (TGDATA) File.

Alternatively, click on the << Back button to return to the Two phase flow - page 2 to view/edit the settings for the fault rock properties used to calculate the relative water and oil permeabilities.

Or click on the Contents button to access the Contents page to view/edit any of the current WizGen page settings, inspect the project's TGDATA file and/or inspect the session log generated by last ViewGen calculation.

Click on Save to save any modifications made on this page to the current TGDATA run file.
Click on Quit to exit from WizGen with or without saving any changes to the TGDATA runfile.