118 PETROLEUM TECHNOLOGY, ECONOMICS, AND POLITICS
of petroleum that are estimated, on a given date, to be potentially
recoverable from undiscovered accumulations.
The ultimate recoverable resource (URR) is the total quantity of
oil that will ever be produced, including the nearly 1 trillion barrels
extracted to date. Estimated ultimate recovery (EUR) is the quantity of petroleum that is estimated, on a given date, to be potentially
recoverable from an accumulation, plus those quantities already
produced therefrom. EUR is not a resource category but it is a term
that may be applied to an individual accumulation of any status/
maturity, whether discovered or undiscovered.
Petroleum quantities classified as reserves, contingent resources
or prospective resources should not be aggregated with each other
without due consideration of the significant differences in the criteria associated with their classification. In particular, there may be a
significant risk that accumulations containing contingent resources
or prospective resources will not achieve commercial production.
The range of uncertainty reflects a reasonable range of estimated
potentially recoverable volumes for an individual accumulation.
Any estimation of resource quantities for an accumulation is subject to both technical and commercial uncertainties, and should, in
general, be quoted as a range. In the case of reserves, and where
appropriate, this range of uncertainty can be reflected in estimates
for proved reserves (IP), proved plus probable reserves (2P) and
proved plus probable plus possible reserves (3P) scenarios. For
other resource categories, the terms low estimate, best estimate,
and high estimate are recommended.
The term best estimate is used as a generic expression for the
estimate considered being the closest to the quantity that will actually be recovered from the accumulation between the date of the
estimate and the time of abandonment. If probabilistic methods are
used, this term would generally be a measure of central tendency
of the uncertainty distribution. The terms low estimate and high
estimate should provide a reasonable assessment of the range of
uncertainty in the best estimate.
For undiscovered accumulations, prospective resources, the
range will, in general, be substantially greater than the ranges for
discovered accumulations. However, in all cases, the actual range
will be dependent on the amount and quality of data (both technical and commercial) that is available for that accumulation. As
more data becomes available for a specific accumulation (e.g. additional wells, reservoir performance data), the range of uncertainty
of petroleum that are estimated, on a given date, to be potentially
recoverable from undiscovered accumulations.
The ultimate recoverable resource (URR) is the total quantity of
oil that will ever be produced, including the nearly 1 trillion barrels
extracted to date. Estimated ultimate recovery (EUR) is the quantity of petroleum that is estimated, on a given date, to be potentially
recoverable from an accumulation, plus those quantities already
produced therefrom. EUR is not a resource category but it is a term
that may be applied to an individual accumulation of any status/
maturity, whether discovered or undiscovered.
Petroleum quantities classified as reserves, contingent resources
or prospective resources should not be aggregated with each other
without due consideration of the significant differences in the criteria associated with their classification. In particular, there may be a
significant risk that accumulations containing contingent resources
or prospective resources will not achieve commercial production.
The range of uncertainty reflects a reasonable range of estimated
potentially recoverable volumes for an individual accumulation.
Any estimation of resource quantities for an accumulation is subject to both technical and commercial uncertainties, and should, in
general, be quoted as a range. In the case of reserves, and where
appropriate, this range of uncertainty can be reflected in estimates
for proved reserves (IP), proved plus probable reserves (2P) and
proved plus probable plus possible reserves (3P) scenarios. For
other resource categories, the terms low estimate, best estimate,
and high estimate are recommended.
The term best estimate is used as a generic expression for the
estimate considered being the closest to the quantity that will actually be recovered from the accumulation between the date of the
estimate and the time of abandonment. If probabilistic methods are
used, this term would generally be a measure of central tendency
of the uncertainty distribution. The terms low estimate and high
estimate should provide a reasonable assessment of the range of
uncertainty in the best estimate.
For undiscovered accumulations, prospective resources, the
range will, in general, be substantially greater than the ranges for
discovered accumulations. However, in all cases, the actual range
will be dependent on the amount and quality of data (both technical and commercial) that is available for that accumulation. As
more data becomes available for a specific accumulation (e.g. additional wells, reservoir performance data), the range of uncertainty