The Influence of Clay Minerals on the Formation and Degradation of Geoporphyrins During Diagenesis or Post Diagenesis
EMSL Project ID
1651
Abstract
Biomarkers are organic compounds in petroleum, or related source rocks, which are related to known precursors through a series of progressive chemical reactions that are dependent on time and temperature. The chemical form of a biomarker can give information about the maturity of a particular shale or other sedimentary rock, which in turn provides information about the oil producing ability of the shale. Biomarkers are also used in petroleum exploration for oil-oil and oil-source rock correlations to determine the relationship of oil deposits located in different places to each other and to the source rocks which produced them. Metalloporphyrins are important biomarkers because their structural parameters are used as a measure of thermal maturity by the petroleum industry. By measuring thermal maturity, information is obtained that reveals whether source rocks are too immature to produce petroleum, mature enough to produce petroleum, or if they are super mature and barren. Porphyrins chelate most of the metals in the periodic table (Quirke, 1987), but the major focus of recent research has been that of the nickel (Ni(II)) and vanadyl (VO(II)) porphyrins because of their predominance in the geosphere. In 1936 Alfred Treibs presented an overview of his earlier research on how the geochemical process might occur when chlorophyll-a is converted to vanadyl DPEP (desoxophylloerythroetioporphyrin). Treibs was the first to elucidate the structure of DPEP in petroleum, and because DPEP contains the same isocyclic ring as in chlorophyll-a, he postulated that DPEP was the product of chlorophyll diagenesis. In 1936 the origins of petroleum were not well understood and a number of people believed in an inorganic origin theory for petroleum (Van Orstrand, 1948), as do some even today (Giardini & Melton, 1983; Osborne, 1986).
Project Details
Project type
Exploratory Research
Start Date
2000-03-21
End Date
2003-01-12
Status
Closed
Released Data Link
Team
Principal Investigator