Volumetric Calculation: Parameters
On the Parameters page you can adjust the ratios in the calculation, override the intermediate volumes. The units of measure can be changed in the Start step.
Volumetrics Components
Gross Pay Rock Volume: Displays the gross volume calculated or entered in the Structure step.
Net to Gross Ratio:Displays the net to gross ratio. May be entered or calculated from the Net to Gross Grid. See Note below.
Net to Gross Grid: A grid may be selected if either a thickness grid or top and base grids were used to calculate the gross pay rock volume. The grid must only contain values within the valid range for a ratio or percent. See Note below.
Net Pay Rock Volume: Displays the net pay rock volume. Enter a number to override the calculated value.
Porosity: Displays the porosity ratio. May be entered or calculated from the Porosity Grid. See Note below.
Porosity Grid: A grid may be selected if either a thickness grid or top and base grids were used to calculate the gross pay rock volume. The grid must only contain values within the valid range for a ratio or percent. See Note below.
Potential Hydrocarbons in Place: Displays the volume of potential hydrocarbons in place. Enter a number to override the calculated value.
Water Saturation (Sw):Displays the water saturation ratio. May be entered or calculated from the Water Saturation Grid. See Note below.
Water Saturation Grid: A grid may be selected if either a thickness grid or top and base grids were used to calculate the gross pay rock volume. The grid must only contain values within the valid range for a ratio or percent. See Note below.
Hydrocarbons in Place: Displays the volume of hydrocarbons in place. Enter a number to override the calculated value.
Formation Volume Factor:Displays the formation volume factor ratio. May be entered or calculated from the FVF Grid. See Note below.
FVF
Grid:
A
grid may
be selected if either a thickness grid or top and base grids were used
to calculate the gross pay rock volume. The grid must only contain
values within the valid range for a ratio or percent. See Note
below.
HCIP
(@ std temp./press.):
Displays the volume of hydrocarbons in place at standard
temperature and pressure. Enter a number to override the
calculated value.
Recovery Factor:Enter the recovery factor ratio. See Note below.
Recoverable
Hydrocarbons:
Displays the
volume of recoverable hydrocarbons.
Note:Entering
Ratios: Each of the ratio
fields (Net to Gross Ratio, Porosity, Water
Saturation, Formation Volume Factor, Recoverable Hydrocarbons) has a
selection beside it which allows you to choose either Ratio or Percent.
This selection applies to the number entered in the ratio
field, and also to the grid specified for that ratio, if there is one.
Ratio values must be between zero and one, and percent values
must be between zero and one hundred (100). If a grid was
selected for the ratio, the number shown in the ratio field is
calculated by weighting the grid values with the portion of the volume
to which they apply. Entering a number in the ratio field
will remove the selected grid.
Other Controls
Show
Summary:
Display the calculation
summary window.
The Volumetric Calculation
The volume of recoverable hydrocarbons is calculated using the
following formula:
Where Sw is the Water Saturation ratio, and FVF is the Formation Volume Factor ratio, each given as a number between zero and one (0.0: 1.0).
The Gross Pay Rock Volume may be calculated by:
- defining structural aspects of the volume by selecting grids which contain subsea elevations, and by entering optional gas/oil and hydrocarbon/water contact elevations;
- providing a thickness grid which contains data points which describe the thickness of the volume at discrete points;
- entering the surface area
and thickness of the volume, or
entering the Gross Pay Rock Volume directly.
There are intermediate volumes calculated, as shown in the table below.
Intermediate Volume |
Calculation |
| Net Pay Rock Volume | Gross Pay Rock Volume multiplied by Net to Gross Ratio |
| Potential Hydrocarbons in Place | Net Pay Rock Volume multiplied by Porosity ratio |
| Hydrocarbons in Place (HCIP) | Potential Hydrocarbons in Place multiplied by the difference of one and the Water Saturation ratio |
| Hydrocarbons in Place at Standard Temperature and Pressure (STP) | HCIP multiplied by the inverse of the Formation Volume Factor |
| Recoverable Hydrocarbons | HCIP @ STP multiplied by Recovery Factor |
— MORE INFORMATION
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