Source Rock Flashcards
A sedimentary rock that contains sufficient organic matter such that when it is buried and heated, it will produce petroleum.
Source Rock
Chemical composition of organic matter is
diverse because the organisms from which it is derived are complex. The principal biological components of living organisms are proteins, carbohydrates, lipids, and lignin.
Organic Matter
Are fatty organic compounds, insoluble in water, and found in most abundance in algae, pollen, and spores. Rich in hydrogen, and hence yield high volumes of hydrocarbon molecules on maturation.
Lipids
The lipid group contains a special group of compounds called _______?
Isoprenoids
A class of hydrocarbon polymers consisting of aliphatic and aromatic structures.
Lignins
What are the two basic requirements for the generation and preservation of organic matter in sediments
High Organic Matter Productivity
Anoxic Environment
What are the depositional environment with high OM productivity?
Continental Margins
Deltas and Restricted Seas
Lagoon in Warm Margins
Lakes
What are the two (2) types of organic matter?
Bitumen
Kerogen
Composed of compounds that are soluble in organic solvents.
Bitumen
Most abundant organic component on earth.
Kerogen
Four (4) types of Kerogen.
Liptinite
Exinite
Vitrinite
Inertinite
Has a high hydrogen to carbon ratio but a
low oxygen to carbon ratio. It is oil-prone, with a high yield (up to 80%). It is derived mainly from an algal source, rich in lipids, which formed in lacustrine and/or lagoonal environments. Liptinite fluoresces under UV light.
Type I - Liptinite
Has intermediate hydrogen to carbon and oxygen to carbon ratios. It is oil- and gas-prone, with yields of 40—60%. The source is mainly membranous plant debris (spores, pollen, and cuticle), and
phytoplankton and bacterial microorganisms in marine sediments.
Type II - Exinite
What type of kerogen contains high proportion of sulfur?
Type II-S Kerogen
This type of kerogen is the most abundant.
Type II - Exinite
Has a low ratio of hydrogen and high ratio of oxygen relative to carbon, and therefore forms a low yield kerogen, principally generating gas. The primary source is higher plant debris found in coals and/or coaly sediments. It does not fluoresce under UV light; however, it is increasingly reflective at higher levels of maturity and therefore can be used as an indicator of source-rock maturity.
Type III - Vitrinite
Is the non-fluorescing product of any of the above kerogens. It is high in carbon and very low in hydrogen, and is often termed “dead-carbon,” having no effective potential to yield oil and gas.
Type IV - Inertinite
Kerogen is composed of large hydrocarbon molecules that are 1.)______________, but will break down into smaller molecules of liquid and gaseous hydrocarbon compounds with progressive exposure to higher temperatures.
- Stable at low temperature
Controls of transformation.
Temperature
Nature and abundance of kerogen in source rock
The most important control.
Temperature
The less important control.
Nature and abundance of kerogen in source rock
