P352-TH DIAMONDOIDS AND BIOMARKERS IMPROVE UNDERSTANDING OF OIL CRACKING, MIXING, AND GEOCHEMICAL CORRELATION ON THE NORTH SLOPE, ALASKA

• Main Authors: Ye Wang, J. Michael Moldowan, Geoff Bott, Kenneth J. Bird, Leslie B. Magoon, Kenneth E. Peters
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: parameters include; 1) the NDR ratio [24-nordiacholestane/(24- and 27-nordiacholestane; north slope; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.500.814; http://www.imog2007.org/files/Thursday Posters/Thursdays Posters Petroleum composition/Thursday Petroleum composition.pdf

Due to high thermal stability, diamondoids resist oil cracking and become more concentrated, while biomarkers crack and decrease in concentration. Therefore, the extent of oil cracking can be investigated by plotting both diamondoid and biomarker concentrations. Furthermore, mixtures of high- and low-maturity oil can be identified when concentrations of both biomarkers and diamondoids are high. Forty-one crude oil samples from the North Slope of Alaska have variable diamondoid and biomarker concentrations, which indicate different extents of oil cracking (Figure 1). Some of the samples are mixtures of high- and low-maturity components because they contain high concentrations of both diamondoids and biomarkers. Components of these mixtures were identified using compound-specific isotope analysis of diamondoids (CSIAD) and light hydrocarbons and by age-related biomarker analysis. The CSIA analyses were used to correlate the high-maturity components, while biomarkers, especially those providing information on the age of the source rock, were used to correlate the lower-maturity components. Five source-rock intervals for the oil samples can be identified by their biomarker characteristics and the CSIA analyses: Carboniferous-Permian Lisburne Formation, Triassic