Definitions of gross, net and total volumes
In API; Manual of Petroleum Measurement Standards Chapter 1-Vocuabulary, second edition, the
following definitions exist:
Volume, gross:
The indicated volume multiplied by the meter factor (MF) for the particular liquid and flow rate under
which the meter was proved
Volume, gross observed; Abbreviated GOV:
The total volume of all petroleum liquids and sediment and water, excluding free water, at observed
temperature and pressure.
Volume, gross standard; Abbreviated GSV:
(a The total volume of all petroleum liquids and sediment and water, excluding free water, corrected by
the appropriate volume correction factor (Ci1) for the observed temperature and API gravity, relative
density, or density to a standard temperature such as 60oF or 15oC and also corrected by the
applicable pressure correction factor (Cp1) and meter factor; (b) the gross volume at standard
temperature corrected to standard pressure. Gross standard volume = closed meter reading – open
meter reading x MF x Ci1 x Cp1.
Volume, net standard; abbreviated NSV:
The total volume of all petroleum liquids excluding sediment and water and free water, corrected by
the appropriate volume correction factor (Ci1) for the observed temperature and API gravity, relative
density, or density to a standard temperature such as 60oF or 15oC and also corrected by the
applicable pressure correction factor (Cp1) and meter factor.
Volume, total calculated; abbreviated TCV:
The total volume of all petroleum liquids and sediment and water, corrected by the appropriate volume
correction factor (Ci1) for the observed temperature and API gravity, relative density, or density to a
standard temperature such as 60oF or 15oC and also corrected by the applicable pressure correction
factor (Cp1) and meter factor, pluss all free water measured at observed temperature and pressure
(gross standard volume plus free water).
Volume, total observed; abbreviated TOV:
The total measured volume of all petroleum liquids, sludges, sediment and water, and free water at
observed temperature and pressure.
In ISO 1998 “Petroleum industry – Terminology “ the following definitions exist
Gross observed volume
Volume of oil including dissolved water, suspended water and suspended sediment but excluding free
water and bottom sediment, measured at the oil temperature and pressure prevailing.
Gross standard volume
Volume of oil including dissolved water, suspended water and suspended sediment but excluding free
water and bottom sediment, calculated at standard conditions.
Net observed volume
Volume of oil excluding total water and total sediment, measured at the oil temperature and pressure
prevailing.
Net standard volume
Volume of petroleum liquids, excluding sediment and water, corrected to standard conditions of
temperature and pressure.
Total observed volume
Volume of oil including total water and total sediment, measured at the oil temperature and pressure
prevailing.
Total standard volume
Total volume at standard temperature and pressure.
There seems to be some confusion around these in the definitions in the Production daily reporting
project.
For example:
The reporting term “Daily Oil gross production Volume” is defined as “Total measured produced
volume of oil on the installation including BS & W in 24 hours measured in standard cubic meter.”
Depending on the unit of measure it would be logical to define the term as a Gross Observed Volume
or a Gross Standard Volume, but the prevailing definition is a variant of the definitions of the “Total
observed volume” or “total standard volume” defined in the standards.
I suggest adopting the volume definitions from API or ISO in the project. First priority should be API,
when a definition in API is missing ISO should be used.