Gross to Net Volume

For accounting and engineering applications that are referencing volumes of material, it is necessary to convert the observed volume at operating conditions to a net standard volume. This net standard volume must be at normal conditions and corrected for such items as the following:

• Sediment and water in the material
• Container adjustments
• Temperature adjustments

The calculation procedure from total observed volume to a net standard volume is as follows.

Where:

TOV = Total observed volume.

GOV = Gross observed volume.

GSV = Gross standard volume.

NSV = Net standard volume.

To calculate the GOV from TOV use the following equation.

To calculate the GSV from GOV use the following equation.

To calculate the NSV from GSV use the following equation.

Where:

CSW = Correction for sediment and water and is equal to: (100 – SW/100)

if SW = Percentage of sediment and water

or

CSW = Correction for sediment and water and is equal to: (1 – SW)

if SW = fraction of sediment and water

The definitions of the terms are listed below.

SW = Sediment and water.

CTSh = Shell temperature correction factor. See the Shell Temperature Correction Factor calculation also in the Sigmafine Data Reference.

FRA = Floating roof adjustment. See the “Floating Roof Correction” document.

FW = Free water quantity deduction. This is water not suspended in the hydrocarbon liquid.

GOV = Gross observed volume. This is the total volume of hydrocarbon liquid and sediment & water excluding free water, at observed temperature.

GSV = Gross standard volume. This is the total volume of hydrocarbon liquid and sediment and water excluding free water, corrected by the VCF.

GSM = Gross standard mass. This is the mass of the GSV quantity.

NSV = Net standard volume. This is the total volume of hydrocarbon liquid excluding sediment & water and free water, corrected by the VCF.

NSM = Net standard mass. This is the mass of the NSV quantity.

TCV = Total calculated volume. This is the total volume of hydrocarbon liquid and sediment & water corrected by the VCF and free water. (GSV plus FW).

TOV = Total observed volume. This is the total volume of hydrocarbon liquids, sediment & water, free water at observed temperature. See the ‘Tank Volume Calculation From Gauges’ Data Reference appendix.

VCF = Volume correction factor. See the “Product Volume Correction Factor” calculation also in the Sigmafine Data Reference.

EXAMPLE: Gross to Net Volume

A tank has the following values for the necessary attributes.

Tank Attribute Values

Attribute	Observed Data
Total Observed Volume	435,218.32 bbl
Free Water Quantity Deduction	154.37 bbl
Shell Temperature Correction Factor	1.00032
Floating Roof Adjustment	37.89 bbl
Volume Correction Factor	0.9868
Sediment and water percent	0.12%

The calculations below show how the Attribute values were used to calculate the Net Standard Volume (NSV).

NSV = 428905.79 bbl

See Configuring - Gross to Net Volume Calculation for details on how to configure this calculation.