46 PETROLEUM TECHNOLOGY, ECONOMICS, AND POLITICS
information system (TORIS). This resulted in the classification and
description of 2,300 light-oil reservoirs (greater that 20°API), collectively containing 308 billion barrels of original oil-in-place (OOIP)
(Ray et al, 1991).
Reservoirs within the various classes are expected to manifest
distinct types of reservoir heterogeneity as a consequence of their
similar lithology and depositional histories. The creation of subclasses assists in the analysis of the impact of post deposition events
on reservoir heterogeneity, which also leads to reservoir evaluation
and the potential for economic viability of the reservoir.
In 1975, as part of the reaction to the energy crisis, the Securities
and Exchange Commission (SEC) was interested only in the proved
reserves (Chapter 4) and, by inference, interested only in those reservoirs which contain proved reserves.
On the basis of the SEC definition of reserves, reservoirs are
known and proven if they contained known and proven reserves
that could be recovered with reasonable certainty in future years
under existing economic and operating conditions. Thus, reservoirs
were classified as proven if economic producibility is supported by
either actual production or conclusive formation test. Furthermore,
the area of a reservoir that is considered proven includes the portion of the reservoir delineated by drilling. The immediately adjoining portions of the reservoir that were not yet drilled but could be
reasonably judged as economically productive on the basis of available geological and engineering data were also included.
In addition, reservoirs that could produce oil economically
through the application of improved recovery techniques, such as
fluid injection, are included in the proven reservoir classification
only when successful testing by a pilot project — or the operation
of an installed program in the reservoir — provides support for the
engineering analysis on which the project or program was based.
Reservoirs that were considered proven did not include reservoirs that contained crude oil that may become available from
known reservoirs but is classified separately as indicated additional reserves. Unproven reservoirs also included reservoirs containing crude oil in which the recovery of the crude oil is subject
to reasonable doubt because of uncertainty as to geology, reservoir
characteristics, or economic factors. Of course, undrilled prospects
are also included in the unproven reservoir category.
In summary, the proved developed reservoirs (as deduced from
the SEC classification of reserves) are those reserves that produce oil
from existing wells with existing equipment and operating methods.
information system (TORIS). This resulted in the classification and
description of 2,300 light-oil reservoirs (greater that 20°API), collectively containing 308 billion barrels of original oil-in-place (OOIP)
(Ray et al, 1991).
Reservoirs within the various classes are expected to manifest
distinct types of reservoir heterogeneity as a consequence of their
similar lithology and depositional histories. The creation of subclasses assists in the analysis of the impact of post deposition events
on reservoir heterogeneity, which also leads to reservoir evaluation
and the potential for economic viability of the reservoir.
In 1975, as part of the reaction to the energy crisis, the Securities
and Exchange Commission (SEC) was interested only in the proved
reserves (Chapter 4) and, by inference, interested only in those reservoirs which contain proved reserves.
On the basis of the SEC definition of reserves, reservoirs are
known and proven if they contained known and proven reserves
that could be recovered with reasonable certainty in future years
under existing economic and operating conditions. Thus, reservoirs
were classified as proven if economic producibility is supported by
either actual production or conclusive formation test. Furthermore,
the area of a reservoir that is considered proven includes the portion of the reservoir delineated by drilling. The immediately adjoining portions of the reservoir that were not yet drilled but could be
reasonably judged as economically productive on the basis of available geological and engineering data were also included.
In addition, reservoirs that could produce oil economically
through the application of improved recovery techniques, such as
fluid injection, are included in the proven reservoir classification
only when successful testing by a pilot project — or the operation
of an installed program in the reservoir — provides support for the
engineering analysis on which the project or program was based.
Reservoirs that were considered proven did not include reservoirs that contained crude oil that may become available from
known reservoirs but is classified separately as indicated additional reserves. Unproven reservoirs also included reservoirs containing crude oil in which the recovery of the crude oil is subject
to reasonable doubt because of uncertainty as to geology, reservoir
characteristics, or economic factors. Of course, undrilled prospects
are also included in the unproven reservoir category.
In summary, the proved developed reservoirs (as deduced from
the SEC classification of reserves) are those reserves that produce oil
from existing wells with existing equipment and operating methods.