OVERBURD
Recognised by the OPM Flow parserPROPS
The OVERBURD keyword defines the overburden pressures versus depth relationship to be applied for when the rock compaction option has been invoked by the ROCKCOMP keyword in the RUNSPEC section.
The rock compaction pore volume and transmissibility multipliers, entered via the ROCKTAB, ROCK2D and ROCK2DTR keywords, are applied to the pore pressure, unless the OVERBURD keyword is included in the input deck. When the OVERBURD keyword is present the multipliers are applied to the effective pore volume pressure, that is [P sub (effective )~=~ P sub ( Pressure )`-`P sub( overburden )]. If the keyword is not present in the input deck then the overburden pressure is set to zero.. If the keyword is not present in the input deck then the overburden pressure is set to zero.
This keyword should only be used if compaction option has been enabled.
Notes:
The keyword is followed by NTROCC tables as declared on the ROCKCOMP keyword in the RUNSPEC section.
Each table must contain a minimum of two rows and a maximum of NPPVT rows as declared on the TABDIMS keyword in the RUNSPEC section.
Each table is terminated by a “/” and there is no “/” terminator for the keyword.
See also the ROCKTAB, ROCK2D, ROCK2DTR, and ROCKWNOD keywords in the PROPS section.
- Records
- Fixed number of records
- Variadic
- The record accepts a variable number of items
Parameters
| No. | Name | Description | Type | Dimension | Field | Metric | Lab | Default |
|---|---|---|---|---|---|---|---|---|
| 1 | DATAmanual: DEPTH | A columnar vector of real monotonically increasing down the column values that defines the depth for corresponding overburden pressure parameter PRESS. | DOUBLE | Length, Pressure | feet | m | cm | None |
| 2 | PRESS | A columnar vector of real monotonically increasing down the column values that defines the corresponding overburden pressure for the given DEPTH. | psia | bars | atm | None |
Example
The example below defines three overburden tables, assuming NTROCC is equal to three on the ROCKCOMP keyword and NPPVT is greater than or equal to four on the TABDIMS keyword.
--
-- OVERBURDEN PRESSURE VERSUS DEPTH TABLES
--
OVERBURD
-- DEPTH OVERBURDEN
-- FEET PRESSURE
-- ------ ----------
1000.0 300.000
2000.0 600.000
3000.0 900.000
4000.0 1200.000 / TABLE N0. 01
-- DEPTH OVERBURDEN
-- FEET PRESSURE
-- ------ ----------
1000.0 200.000
2000.0 400.000
3000.0 800.000
4000.0 1000.000 / TABLE N0. 02
-- DEPTH OVERBURDEN
-- FEET PRESSURE
-- ------ ----------
1000.0 400.000
2000.0 800.000
3000.0 1100.000
4000.0 1500.000 / TABLE N0. 03
Note that there must be exactly NTROCC tables entered for this keyword, otherwise an error will occur.
--
-- ROCK COMPACTION TABLES
--
ROCKTAB
-- PRESS PORV TX(YZ)
-- MULT MULT
-- ------ ------ ------
1000.0 0.9600 0.9650
1500.0 0.9800 0.9850
3000.0 0.9900 0.9950
4500.0 1.0000 1.0000
4750.0 1.0100 1.0100 / TABLE NO. 01
-- PRESS PORV TX(YZ)
-- MULT MULT
-- ------ ------ ------
1000.0 0.9600 0.9650
1500.0 0.9800 0.9850
3000.0 0.9900 0.9950
4500.0 1.0000 1.0000
4750.0 1.0100 1.0100 / TABLE NO. 02
-- PRESS PORV TX(YZ)
-- MULT MULT
-- ------ ------ ------
1000.0 0.9600 0.9650
2000.0 0.9800 0.9850
3000.0 0.9900 0.9950
4000.0 1.0100 1.0100 / TABLE NO. 03
Here ROCKTAB tables one and two are identical.Manual source: parts/chapters/subsections/8.3/OVERBURD.fodt