CRUDE OIL CLASSIFICATION AND BENCHMARKS
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Category Cl reserves are the reserves of a reservoir (or of a portion thereof) where the oil content has been determined on the basis
of commercial flows of oil and positive results of geological and
geophysical exploration of non-probed wells. In addition, the type,
shape, and size of the reservoir as well as the formation structure of
the oil-bearing reservoirs have been determined from the results of
drilling exploration and production wells and by those geological
and geophysical exploration techniques that have been field-tested
for the applicable area. The lithology (rock type and content), reservoir type and characteristics, oil and natural gas saturation, oil displacement ratio, and effective oil and natural gas saturation depth
of the productive strata should have been studied based on drill
cores and geophysical well exploration materials. The composition
and characteristics of crude oil and well productivity are also necessary for this category.
Category Cl reserves are estimated on the basis of results of geological exploration work and production drilling and must have
been studied in sufficient detail to yield data from which to draw
up either a trial industrial development project in the case of a natural gas field or a technological development scheme in the case of
an oil field.
Category C2 reserves are preliminary estimated reserves of
a deposit calculated on the basis of geological and geophysical
research of unexplored sections of deposits adjoining sections of
a field containing reserves of higher categories and of untested
deposits of explored fields. The shape, size, structure, level, reservoir types, content, and characteristics of the hydrocarbon deposit
are determined in general terms based on the results of the geological and geophysical exploration and information on the more fully
explored portions of a deposit. Category C2 reserves are used to
determine the development potential of a field and to plan geological, exploration and production activities.
Category C3 resources are prospective reserves prepared for the
drilling of (1) traps within the oil-and-gas bearing area, delineated
by geological and geophysical exploration methods tested for such
area and (2) the formation of explored fields which have not yet
been exposed by drilling. The form, size, and stratification conditions of the assumed deposit are estimated from the results of
geological and geophysical research. The thickness, the reservoir
characteristics of the formations, and the composition and characteristics of hydrocarbons are assumed to be analogous to those for
explored fields. Category C3 resources are used in the planning of
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Category Cl reserves are the reserves of a reservoir (or of a portion thereof) where the oil content has been determined on the basis
of commercial flows of oil and positive results of geological and
geophysical exploration of non-probed wells. In addition, the type,
shape, and size of the reservoir as well as the formation structure of
the oil-bearing reservoirs have been determined from the results of
drilling exploration and production wells and by those geological
and geophysical exploration techniques that have been field-tested
for the applicable area. The lithology (rock type and content), reservoir type and characteristics, oil and natural gas saturation, oil displacement ratio, and effective oil and natural gas saturation depth
of the productive strata should have been studied based on drill
cores and geophysical well exploration materials. The composition
and characteristics of crude oil and well productivity are also necessary for this category.
Category Cl reserves are estimated on the basis of results of geological exploration work and production drilling and must have
been studied in sufficient detail to yield data from which to draw
up either a trial industrial development project in the case of a natural gas field or a technological development scheme in the case of
an oil field.
Category C2 reserves are preliminary estimated reserves of
a deposit calculated on the basis of geological and geophysical
research of unexplored sections of deposits adjoining sections of
a field containing reserves of higher categories and of untested
deposits of explored fields. The shape, size, structure, level, reservoir types, content, and characteristics of the hydrocarbon deposit
are determined in general terms based on the results of the geological and geophysical exploration and information on the more fully
explored portions of a deposit. Category C2 reserves are used to
determine the development potential of a field and to plan geological, exploration and production activities.
Category C3 resources are prospective reserves prepared for the
drilling of (1) traps within the oil-and-gas bearing area, delineated
by geological and geophysical exploration methods tested for such
area and (2) the formation of explored fields which have not yet
been exposed by drilling. The form, size, and stratification conditions of the assumed deposit are estimated from the results of
geological and geophysical research. The thickness, the reservoir
characteristics of the formations, and the composition and characteristics of hydrocarbons are assumed to be analogous to those for
explored fields. Category C3 resources are used in the planning of