22. genetic classification of petroleum systems
Post on 08-Nov-2014
113 Views
Preview:
DESCRIPTION
TRANSCRIPT
22.
Genetic Classification
of Petroleum Systems
by: Awang Harun Satyana
INDONESIAN PETROLEUM ASSOCIATION (IPA)
REGULAR COURSE, SOLO – CENTRAL JAVA, 4-8 JUNE 2012
1. volumetrically adequate petroleum generation, occurring during or
after the time of trap formation;
2. favorable migration-drainage geometry, leading to the focused
movement of hydrocarbons into traps rather than to dispersion and
loss of hydrocarbons in either subsurface migration “waste zone”
or up to the surface;
3. the existence of volumetrically adequate traps, capable of retaining
their petroleum charge from the earliest time of trap filling to the
present day.
Three important geologic factors control the accumulation
of petroleum in the subsurface and, thus are essential to
the existence of viable “petroleum systems:
Demaison and Huizinga (1991)
Two Subsystems of Petroleum System
1. A generative subsystem provides a certain supply of petroleum during a
given time span. Generative subsystems are essentially controlled by
chemical processes, consisting of biochemical transformation of dead
organisms into kerogen during the source depositional stage and thermo-
chemical kinetics, which control the transformation of kerogen into
petroleum.
2. A migration-entrapment subsystem gathers petroleum from the mature
source rocks and distributes it in a manner that may lead to either
concentration of petroleum into economic accumulations or loss of
petroleum due to dispersion and destruction. Migration-entrapment
subsystems are predominantly controlled by physical processes, including
the buoyant rise of petroleum in water, fluid flow and capillary pressures in
porous media, and pressure-temperature-composition relationships
affecting phase behavior before and during petroleum entrapment.
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Purpose of Genetic Classification
• Describe and predict the relative charging
potential of petroleum systems and, thus
segments of petroleum basins,
• Describe geographic location of zones of
petroleum occurrence or plays in basins.
Demaison and Huizinga (1991)
Genetic Classification of Petroleum System
1. Combining qualifiers from each of the following three
categories: (1) charge factor (supercharged, normally
charged, undercharged), (2) migration drainage style
(vertically drained, laterally drained), and (3)
entrapment style (high impedance, low impedance).
2. Application of these working concepts should help to
significantly reduce geologic risk, particularly in new
ventures-type exploration.
Demaison and Huizinga (1991)
Genetic Classification of Petroleum System
1. The charge factor is estimated on the basis of the richness and
volumetrics of mature source rocks. The source potential index
(SPI), which combines source rock richness and thickness into a
single parameter is introduced.
2. The migration drainage style is determined from the structural and
stratigraphic framework of a basin. Recognition of the dominant
migration style helps to predict the location of zones of petroleum
occurrence in relation to the hydrocarbon kitchens.
3. The entrapment style, which is also dependent on the structural
framework and the presence and effectiveness of seals, describes
the degree of resistance (impedance) working against dispersion
of the petroleum charge.
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Migration Drainage Styles
1. Short-range lateral migration along permeable carrier beds and vertical
migration through fault and fracture zones are the most commonly observed
mechanisms of petroleum charging into traps.
2. The petroleum accumulations in most basins are commonly found over or
immediately adjacent to hydrocarbon kitchen. In fact, most commercial
petroleum accumulations result from short lateral-migration distances (less
than 30 km).
3. Low-angle lateral migration is physically less efficient that vertical migration.
The buoyant force of an oil filament of fixed length and volume is several times
higher for purely vertical displacement than for lateral upward transport along
a gently dipping carrier bed. Consequently, lateral migration is more
demanding on the amount of oil needed to create an adequate buoyant force
capable of breaking through capillary pressure barriers in the carrier unit
(Illing, 1939).
4. Fault and fracture systems that are persistently reactivated by tectonic
movements may serve as highly efficient avenues for vertical migration of
petroleum.
Demaison and Huizinga (1991)
Migration Drainage Styles
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Entrapment Styles
1. The degree of structural deformation and seal integrity are the two
key factors used to qualify entrapment styles. Together, these
factors control the degree of impedance working against the
natural tendency for petroleum to become randomly dispersed and
lost in sedimentary basins.
2. High-impedance systems are characterized by laterally continuous
seals coupled with a moderate to high degree of structural
deformation.
3. Low-impedance systems are characterized by either a high degree
of regional seal continuity and low degree of structural
deformation, or low degree of regional seal effectiveness, coupled
with a high or low degree of structural deformation.
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
Demaison and Huizinga (1991)
top related