Page 18 - Primer on Enhanced Oil Recovery

Hydrocarbon and oil reserves classification 9

2.1.2 Condensate

Condensate is a mixture of light hydrocarbons with relatively low molecular weight
which exists as a liquid at standard conditions (standard temperature and pressure).
Chemically condensate does contain light carbohydrates but not propane and eth-
ane. In some cases condensate contains small amounts of sulfur compounds.
Condensate low density leads to high API gravity numbers, which are in the
0
region of 50 120 API. Condensate comes from an oil well as so called associate
gas (wet gas) and is also refereed at certain stages as lease condensate. In an oil for-
mation condensate can exist as dissolved in oil/connate water gas or as a separate
phase. All condensate behavior in the formation is fully defined by the formation
chemistry, temperature and pressure. If the formation pressure during an oil produc-
tion is not maintained by water or gas injection and formation pressure is lowered
then condensate can start consolidating as a separate phase.
One of the main parameters to characterise condensate are condensate-gas factor
and the pressure of the condensation onset.
The same as oil, condensate volume is measured in barrels at the standard
conditions.

2.2 Oil reserve classification

Development of human society at large extend depends, at the present, on availabil-
ity of non-renewable hydrocarbons (gas, oil and bitumen). Many factors and tech-
nologies need to be taken into consideration for hydrocarbon extraction. The oil
production includes complex interplays of geology, technology, social, financial,
political and environmental challenges. All this needs to be taken into the consider-
ation in oil exploration, extraction and processing.
In order to evaluate commercial viability of hydrocarbon formation, on the first
place, a complex geological study need to be undertaken. Various international and
national classifications and schemes can be applied to indicate industrial signifi-
cance of proven hydrocarbon reserves in the formation.
Existing classifications are vigorously set and are closely monitored by the states
(governments), fiscal organs, banks and companies management. All this monitor-
ing allows for a well-structured set of geological and exploitation steps. Reserve
management then forms the basis of the reserve mineralogical and energy potential.
The potential and development strategies are crucial for the reserve owners and
developers.
The classification of hydrocarbon reserves (resources) (gas, oil, bitumen) estab-
lishes uniform principles for calculating and assessing readiness for industrial
development. Classification is an extremely important undertaking and much con-
sideration and attention are given to it. Along with the generally accepted interna-
tional classifications such as SPE/WPC/AAPG/SPEE (“SPE-PRMS”) and SEC,
which are used uniformly by all the oil companies of the world, other classifications