Petroleum sources potential of terrigenous source rocks
The work has been focused on the generation of petroleum liquids from coals and coaly shales, and the characteristics and diagnostic features of such liquids. Although generation of petroleum from coals has been, and occasionally still is, debated, the results of the project clearly demonstrate its feasibilty and validity.
Recurring reports in the literature of oil accumulations sourced from coals and sediments containing predominantly terrestrial organic matter have shown that such deposits may actually be oil-prone. However, the factors determining the extent to which such deposits are oil-generative relative to gas-generative are imperfectly understood. The projective of the present research project is to contribute to the understanding of these factors. A set of samples is selected, which contain predominantly terrigenous organic matter, and which represent a wide span of geological ages and origins. The main focus will be placed on samples from the North Atlantic region, but samples from other parts of the world may be included as needed. The samples are characterised, and their petroleum source potential asessed by detailed organic geochemical and petrographic analyses as well as kinetic studies. Hydrous pyrolysis experiments are carried out on series of samples, and maturation curves are constructed. Generation characteristics, petrographic compositions and other data are subjected to multivariate statistical analyses, aimed at elucidating the relationship between petroleum generation characteristics and kerogen compositions. The results are expected to contribute to the clarification of questions regarding the crucial factors determining generation characteristics, gas oil ratios, relative importance of Angiosperm/Gymnosperm organic matter, etc.
The objectives of the EFP-98 research project 'Petroleum source potential of terrigenous source rocks' were to investigate: 1) The capacity of organic-rich terrigenous deposits to generate and expel petroleum liquids. 2) The composition of petroleum liquids generated from such sources. 3) The relationships between generation potential, petroleum characteristics, and the kerogen composition. 4) Relationships between the pyrolytically defined distribution of gas-prone, oil-prone, and inert kerogen and the kerogen composition as defined optically. 5) Kinetics of petroleum generation from terrigenous deposits. 6) Maturity effects on the generation of petroleum liquids from terrigenous deposits. 7) Possible relationships between generation capacity and geological age, e.g. differences between gymnosperm-derived versus angiosperm-derived kerogen. 8) Improved numerical/mathematical modelling of the generation of petroleum liquids from terrigenous deposits. With the exception of the latter two objectives, which for technical/practical reasons described elsewhere (yearly report January 31st, 2000) had to assume lower priority or be excluded from the project, all objectives mentioned have been addressed in varying degrees of detail; the results have been reported in a number of published papers and conference contributions. The work has been focused on the generation of petroleum liquids from coals and coaly shales, and the characteristics and diagnostic features of such liquids. Although generation of petroleum from coals has been, and occasionally still is, debated, the results of the project clearly demonstrate its feasibilty and validity. Moreover, relationships between coal composition and the kinetics of petroleum formation have been shown. Detailed biomarker analyses, including extensive synthesis work, have led to an improved understanding of the significance and origin of certain biomarkers that are assumed to be diagnostic of terrigenous or marine source depositional environments, and a number of unknown compounds have been identified. The results offer insights into hitherto unknown causalities between petroleum composition and source depositional environments. The project has contributed important new information that is potentially useful for petroleum exploration both within Danish territory as well as internationally
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| Geological Energy of Canada (CA) | ||
| Universitetet i Bergen (NO) |
Contact
Thoravej 8
DK-2400 København NV, Denmark
Bojesen-Koefoed, Jørgen A. (seniorforsk.), 38142000, geus@geus.dk
Øvr. Partnere: Geological Energy of Canada (CA); Universitetet i Bergen (NO)
