`OUTRAD`

Recognised by the OPM Flow parserGRID

OUTRAD defines the OUTER radius of the reservoir model for a radial or spider grid geometry. The RADIAL or SPIDER keyword in the RUNSPEC should be activated to indicate that radial or spider geometry is being used.

This keyword is not supported by OPM Flow but would change the results if supported so the simulation will be stopped.

Notes:

The keyword is terminated by a “/”.

Note that the SPIDER keyword activates OPM Flow’s radial grid geometry option for the model. This keyword will create a spiderweb-shaped grid based on a corner-point grid using the standard radial grid keywords: INRAD, DRV, DTHETAV, DZ/DZV etc. in the GRID the section. Spider and Radial grids generated by OPM Flow will be displayed the same in OPM ResInsight, as they are both output as Cartesian Irregular Corner-Point Grids. The difference is that the radial model’s pore volumes are adjusted to match the radial geometry pore volumes, whereas the Spider grid volumes are not adjusted.

The keyword allows for an alternative method of entering the size of the R direction grid cells instead of entering the data using the DR or DRV keywords in the GRID section. Given the internal radius set by the INRAD keyword, the external radius set by the OUTRAD keyword and the number of grid cells in the R direction set by the NX variable on the DIMENS keyword in the RUNSPEC section, the R direction cells sizes are computed automatically on a geometric spacing, as defined by:

[{R sub{i}} over {R sub{i-1}} ``=``left( OUTRAD over {R sub{i sub{j}-1}}right)` sup{1 over {left(NX`-`i sub{j}``+``1 right)}}]

(6.12)

[R sub{i}``=``left(R sub{i sub{j}-1} right) left( OUTRAD over {R sub{i sub{j}-1}} right)` sup{left(i`-`i sub{j}`+1` right) over {left(NX`-`i sub{j}``+``1 right)}}]

(6.13)

and the DR value for the ith cell, that is the value that can also be manually entered on the DR keyword in the GRID section, is given by:

[DR sub{ i}~=~R sub{i}``-``R sub{i`-`1}]

(6.14)

Where:

DRi=DR value for the ith cell

Ri=current total radius for the i radii.

Ri-1=total radius for the i – 1 radii.

NX (NR)=number of radial grid cells excluding the inner radius

OUTRAD=the outer radius of the radial grid, the value includes the inner radius.

For example, given an inner radius set to 0.25, an outer radius of 2,050 and the number of cells in the R direction set to ten, then Table 6.100shows the grid size calculations.

OUTRAD Radial Grid Example

INRAD

0.25

OUTRAD

2050.0

Ratio

0.250

0.616

0.366

1.463

1.516

0.900

2.463

3.733

2.217

2.463

9.193

5.460

2.463

22.638

13.445

2.463

55.748

33.109

2.463

137.281

81.533

2.463

338.058

200.777

2.463

832.477

494.420

2.463

2050.000

1217.523

2.463

Total

2050.000

Table 6.100: OUTRAD Radial Grid Example

See also the DR, DRV, DTHETA, DTHETAV and TOPS keywords to fully define a Radial or Spider Grid.

Records: Fixed number of records
Record count: 1
Items per record: 1

Parameters

No.	Name	Description	Type	Dimension	Field	Metric	Lab	Default
1	`RADIUS` manual: `OUTRAD`	A single real positive number greater than INRAD defining the outer radius of a radial grid.	DOUBLE	Length	feet	m	cm	None

Example

--
-- INNER RADIUS OF FIRST GRID BLOCK IN THE RADIAL DIRECTION
--
INRAD
0.25 /
--
-- OUTER RADIUS OF FIRST GRID BLOCK IN THE RADIAL DIRECTION
--
OUTRAD
2050.0 /
The above example defines the inner radius to be 0.25 and the outer radius to be 2,050 feet. Note that the outer radius includes the inner radius.
| [{R sub{i}} over {R sub{i-1}} ``=``left( OUTRAD over {R sub{i sub{j}-1}}right)` sup{1 over {left(NX`-`i sub{j}``+``1 right)}}] | (6.12) |
|--------------------------------------------------------------------------------------------------------------------------------|--------|
| [R sub{i}``=``left(R sub{i sub{j}-1} right) left( OUTRAD over {R sub{i sub{j}-1}} right)` sup{left(i`-`i sub{j}`+1` right) over {left(NX`-`i sub{j}``+``1 right)}}] | (6.13) |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
| [DR sub{ i}~=~R sub{i}``-``R sub{i`-`1}] | (6.14) |
|------------------------------------------|--------|
| OUTRAD Radial Grid Example |          |          |       |
|----------------------------|----------|----------|-------|
| INRAD                      | 0.25     |          |       |
| OUTRAD                     | 2050.0   |          |       |
| NX                         | 10       |          |       |
| NX                         | Ri       | DR       | Ratio |
| 0                          | 0.250    | 0.250    |       |
| 1                          | 0.616    | 0.366    | 1.463 |
| 2                          | 1.516    | 0.900    | 2.463 |
| 3                          | 3.733    | 2.217    | 2.463 |
| 4                          | 9.193    | 5.460    | 2.463 |
| 5                          | 22.638   | 13.445   | 2.463 |
| 6                          | 55.748   | 33.109   | 2.463 |
| 7                          | 137.281  | 81.533   | 2.463 |
| 8                          | 338.058  | 200.777  | 2.463 |
| 9                          | 832.477  | 494.420  | 2.463 |
| 10                         | 2050.000 | 1217.523 | 2.463 |
| Total                      |          | 2050.000 |       |

Manual source: parts/chapters/subsections/6.3/OUTRAD.fodt