`THPRES`

Recognised by the OPM Flow parserSOLUTION

The THPRES defines the threshold pressure between various equilibration regions that have been defined by the EQLNUM keyword in the REGIONS section. The threshold pressure defines the potential difference between two regions which must be exceeded before flow can occur between the two regions. Once flow occurs the potential between the two regions is reduced by the threshold pressure.

This option must be activated by THPRES variable on EQLOPTS keyword in the RUNSPEC section in order to utilize this feature. Note that the irreversible option, as defined by IRREVER variable on EQLOPTS keyword in the RUNSPEC section, is not supported.

Notes:

The keyword is followed by any number of records with each record terminated by a “/” and the keyword is terminated by a “/”.

See also the MULTREGT keyword in the GRID section that uses the transmissibility between the MULTNUM, FLUXNUM or OPERNUM region arrays to control the flow between various regions within the model.

Note

Care should be taken that cells in different EQLNUM regions are not in communication, as this will result in an unstable initial equilibration.

Records: One or more records, each terminated by /
Items per record: 3

Parameters

No.	Name	Description	Type	Dimension	Field	Metric	Lab	Default
1	`REGION1` manual: `EQLNUM1`	EQLNUM1 is an a positive integer that is greater or equal to one and less than or equal to NTEQUL on the EQLDIMS keyword in the RUNSPEC section, that defines the “from” equilibration region number.	INT		dimensionless	dimensionless	dimensionless	None
2	`REGION2` manual: `EQLNUM2`	EQLNUM1 is an a positive integer that is greater or equal to one and less than or equal to NTEQUL on the EQLDIMS keyword in the RUNSPEC section, that defines the “to” equilibration region number.	INT		dimensionless	dimensionless	dimensionless	None
3	`VALUE` manual: `THPRES`	THPRES defines the threshold pressure from EQLNUM1 to EQLNUM2 and from EQLNUM2 to EQLNUM1. The default value of 1* sets the threshold pressure to a value that initially prevents flow between the two equilibration regions. Any subsequent production or injection in either of the two equilibration regions will therefore result in flow between the two regions. Thus, this default initially isolates the two equilibration regions. If a equilibration region number pair has not been explicitly defined by this keyword the THPRES is set to zero, for no threshold pressure.	DOUBLE	Pressure	psia	barsa	atma	1*

Example

Given NTEQUL is equal to six on the EQLDIMS keyword in the RUNSPEC section,
--
-- EQLNUM EQLNUM THPRES
-- FROM TO VALUE
THPRES
1 2 0.588031 / REGN 1 TO REGN 2
2 1 0.588031 / REGN 2 TO REGN 1
1 3 0.787619 / REGN 1 TO REGN 3
3 1 0.787619 / REGN 3 TO REGN 1
1 4 7.000830 / REGN 1 TO REGN 4
4 1 7.000830 / REGN 4 TO REGN 1
/
The above example defines the threshold pressures between equilibration regions one and two, one and three and one and four. As the threshold pressures between regions one and five and one and six (as well as other combinations), have not been explicitly set in the example, the threshold pressures for these combinations are set to zero.
However, as the irreversible option, as defined by IRREVER variable on EQLOPTS keyword in the RUNSPEC section, is not supported, then example can be simplified to:
--
-- EQLNUM EQLNUM THPRES
-- FROM TO VALUE
THPRES
1 2 0.588031 / REGN 1 AND REGN 2
1 3 0.787619 / REGN 1 AND REGN 3
1 4 7.000830 / REGN 1 AND REGN 4
/
Again, as the threshold pressures between regions one and five and one and six (as well as other combinations), have not been explicitly set in the example, the threshold pressures for these combinations are set to zero.
| Note Care should be taken that cells in different EQLNUM regions are not in communication, as this will result in an unstable initial equilibration. |
|------------------------------------------------------------------------------------------------------------------------------------------------------|

Manual source: parts/chapters/subsections/10.3/THPRES.fodt