NNC
Recognised by the OPM Flow parserGRID
NNC enables Non-Neighbor Connections (“NNC”) to be manually defined. This keyword is normally generated by static modeling software as opposed to be manually entered in the OPM Flow input deck due to the verbosity and complexity of calculating the required parameters for this keyword.
Notes:
Only functionality defined by items (1) to (7) are activated in OPM Flow.
Each record must be terminated by a “/” and the keyword is terminated by a “/”.
Note that although items (8) to (17) for this keyword are not available in OPM Flow, even if they were, it is strongly recommended that these items are defaulted if the data is being entered manually, as opposed to being generated by a pre-processing software.
Care should be taken that cells in different PVTNUM regions (see the PVTNUM keyword in the REGIONS section) are not connected, since the fluid properties are associated with a cell. If for example, a rbbl or a rm3 of oil flows from PVTNUM region 1 to PVTNUM region 2, then the oil properties of that oil will change from the PVT 1 data set to the PVT data set 2. This will result in material balance errors, that may or may not cause numerical issues.
If the transmissibility across a fault needs to be modified see the FAULTS and MULTFLT keywords in the GRID section for an alternative and less complicated method to modifying fault transmissibilities. Transmissibility between reservoir regions can be modified by using MULTREGT keyword, provided MULTNUM has been used to define the inter-region transmissibility region numbers for each grid block. Finally, the MULTX, MULTY and MULTZ series of keywords can be used to modify transmissibility between various cells. All the aforementioned keywords are described in the GRID section.
- Records
- One or more records, each terminated by
/ - Items per record
- 17
Parameters
| No. | Name | Description | Type | Dimension | Field | Metric | Lab | Default |
|---|---|---|---|---|---|---|---|---|
| 1 | I1 | A positive integer that defines the first grid block in the I-direction in a non-neighbor connection, must be greater than or equal to one and less than or equal to NX on the DIMENS keyword in the RUNSPEC section. | INT | None | ||||
| 2 | J1 | A positive integer that defines the first grid block in the J-direction in a non-neighbor connection, must be greater than or equal to one and less than or equal to NY on the DIMENS keyword in the RUNSPEC section. | INT | None | ||||
| 3 | K1 | A positive integer that defines the first grid block in the K-direction in a non-neighbor connection, must be greater than or equal to one and less than or equal to NZ on the DIMENS keyword in the RUNSPEC section. | INT | None | ||||
| 4 | I2 | A positive integer that defines the second grid block in the I-direction in a non-neighbor connection, must be greater than or equal to one and less than or equal to NX on the DIMENS keyword in the RUNSPEC section. | INT | None | ||||
| 5 | J2 | A positive integer that defines the second grid block in the J-direction in a non-neighbor connection, must be greater than or equal to one and less than or equal to NY on the DIMENS keyword in the RUNSPEC section. | INT | None | ||||
| 6 | K2 | A positive integer that defines the second grid block in the K-direction in a non-neighbor connection, must be greater than or equal to one and less than or equal to NZ on the DIMENS keyword in the RUNSPEC section. | INT | None | ||||
| 7 | TRANmanual: TRANSNNC | TRANSNNC is a positive real number greater than or equal to zero that defines the transmissibility between the first grid block (I1, J1, K1) and the second grid block (I2, J2, K2). The default value of zero sets the transmissibility between the two cells to zero. | DOUBLE | Transmissibility | cP.rb/ | cP.rm3/ | cP.rcc/ | 0.0 |
| 8 | IST1manual: ISATNUM1 | ISATNUM1 is a positive integer defining which saturation table number (relative permeability table) to be used for flow from the first grid block to the second grid block. The default value of zero means the existing saturation table allocated to the upstream cell (I1,J1,K1). | INT | 0 | ||||
| 9 | IST2manual: ISATNUM2 | ISATNUM2 is a positive integer defining which saturation table number (relative permeability table) to be used for flow from the second grid block to the first grid block. The default value of zero means the existing saturation table allocated to the downstream cell (I2,J2,K2). | INT | 0 | ||||
| 10 | PRESSURE_manual: IPRSNUM1 | IPRSNUM1 is a positive integer defining which pressure table number (PVT table) to be used for flow from the first grid block to the second grid block. The default value of zero means the existing PVT table allocated to the upstream cell (I1,J1,K1). | INT | 0 | ||||
| 11 | PRESSURE_manual: IPRSNUM2 | IPRSNUM2 is a positive integer defining which pressure table number (PVT table) to be used for flow from the second grid block to the first grid block. The default value of zero means the existing PVT table allocated to the downstream cell (I2,J2,K2). | INT | 0 | ||||
| 12 | VE_manual: FACE1 | FACE1 is a character string that defines the face associated with flow from the first grid block to the second grid block, where FACE1 can have values of: X+, X-, Y+, Y-, Z+, or Z-. | STRING | None | ||||
| 13 | VE_manual: FACE2 | FACE2 is a character string that defines the face associated with flow from the second grid block to the first grid block, where FACE2 can have values of: X+, X-, Y+, Y-, Z+, or Z-. | STRING | None | ||||
| 14 | DIFFUSIVITYmanual: DIFFNNC | DIFFNNC is a positive real number that defines the diffusivity between the first grid block (I1, J1, K1) and the second grid block (I2, J2, K2). | DOUBLE | feet | meters | cm | 0.0 | |
| 15 | SIM_manual: DISPNNC | DISPNNC s a positive real number that defines the dispersion coefficient [1 over ( Area x Porosity)]between the first grid block (I1, J1, K1) and the second grid block (I2, J2, K2), used with the between the first grid block (I1, J1, K1) and the second grid block (I2, J2, K2), used with the DISPERSE option. | DOUBLE | ContextDependent | ft-2 | m-2 | cm-2 | 0.0 |
| 16 | VDFLOW_manual: AREANNC | AREANNC is a positive real number that defines the area associated with the connection between the first grid block (I1, J1, K1) and the second grid block (I2, J2, K2). | DOUBLE | Length* | ft2 | m2 | cm2 | None |
| 17 | VDFLOW_manual: PERMNNC | AREANNC is a positive real number that defines the permeability associated with the connection between the first grid block (I1, J1, K1) and the second grid block (I2, J2, K2). This used by the non-Darcy option. | DOUBLE | Permeability | mD | mD | mD | None |
Example
--
-- MANUALLY DEFINE NON-NEIGHBOR CONNECTIONS
--
-- ------------ BOX ----------- -- TRANSNNC --
-- I1 J1 K1 I2 J2 K2
NNC
1 1 1 1 1 2 0.2500 / SET NNC FOR FAULT
1 1 2 1 1 3 0.2500 / SET NNC FOR FAULT
1 1 3 1 1 4 0.2500 / SET NNC FOR FAULT
/
The above example defines the transmissibility between cells (1, 1, 1) and (1, 1, 2), (1, 1, 2) and (1, 1, 3) and finally between (1, 1, 3) and (1, 1, 4) to be 0.2500.Manual source: parts/chapters/subsections/6.3/NNC.fodt