Role of minerals in the thermal alteration of organic matter. IV. Generation of n-alkanes, acyclic isoprenoids, and alkenes in laboratory experiments

Journal Article · Fri May 01 00:00:00 EDT 1987 · Geochim. Cosmochim. Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(87)90202-X· OSTI ID:7017145

Huizinga, B J; Tannenbaum, E; Kaplan, I R

A series of pyrolysis experiments, utilizing two different immature oil-prone kerogens mixed with common sedimentary minerals (calcite, illite, or Na-montmorillonite), was conducted to study the effects of minerals on the generation of n-alkanes, acyclic isoprenoids, and alkenes during laboratory-simulated catagenesis of kerogen. The influence of clay minerals on the aliphatic hydrocarbons is critically dependent on the water concentration during laboratory thermal maturation. Under extremely low contents of water, C/sub 12+/-range n-alkanes and acyclic isoprenoids are mostly destroyed by montmorillonite but undergo only a minor alteration with illite. Both clay minerals significantly reduce alkene formation during dry pyrolysis. Under hydrous conditions (mineral/water = 2:1), the effects of the clay minerals are substantially reduced. In addition, the dry-pyrolysis experiments show that illite and montmorillonite preferentially retain large amounts of the polar constituents of bitumen, but not n-alkanes of acyclic isoprenoids. Therefore, bitumen fractionation according to polarity differences occurs in the presence of these clay minerals. By this process, n-alkanes, and acyclic isoprenoids are concentrated in the bitumen fraction that is not strongly adsorbed on the clay matrices. In contrast, calcite has no significant influence on the thermal evolution of the hydrocarbons. In addition, calcite is incapable of retaining bitumen. Therefore, the fractionation of n-alkanes or acyclic isoprenoids relative to the polar constituents of bitumen is insignificant in the presence of calcite.

• Research Organization: Univ. of California, Los Angeles (USA)
• OSTI ID: 7017145
• Journal Information: Geochim. Cosmochim. Acta; (United States), Vol. 51:5
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
58 GEOSCIENCES
ALKANES
FRACTIONATION
GEOCHEMISTRY
MATURATION
ALKENES
CALCITE
CATALYTIC EFFECTS
ILLITE
KEROGEN
CATAGENESIS
HYDROTHERMAL ALTERATION
MONTMORILLONITE
BENCH-SCALE EXPERIMENTS
BITUMENS
GREEN RIVER FORMATION
MOISTURE
OIL SHALES
POLARIZATION
PYROLYSIS
PYROLYSIS PRODUCTS
SORPTIVE PROPERTIES
ALKALINE EARTH METAL COMPOUNDS
BITUMINOUS MATERIALS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONACEOUS MATERIALS
CARBONATE MINERALS
CARBONATES
CHEMICAL REACTIONS
CHEMISTRY
CLAYS
DECOMPOSITION
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC FORMATIONS
HYDROCARBONS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MINERALS
ORGANIC COMPOUNDS
ORGANIC MATTER
OTHER ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
SEPARATION PROCESSES
SURFACE PROPERTIES
TAR
THERMOCHEMICAL PROCESSES
040201* - Oil Shales & Tar Sands- Site Geology- (-1989)
580400 - Geochemistry- (-1989)