摘要：

In the first comprehensive study of the Talara basin petroleum system of onshore and offshore northwest Peru, we test oil–source rock correlation through molecular biomarker analysis of oil samples from wells scattered throughout the basin, as well as purported source rocks. The new data presented in this manuscript suggest that the oils constitute one oil family, and that the source rock was a predominant marine clay deposited in an oxic to suboxic environment. Substantial relative amounts of oleanane in each oil sample indicate a notable input of terrestrial organic matter deposited in a mixed marine and terrestrial environment (probably deltaic). The high ratio of 24-norcholestanes to 27-norcholestanes and C25 highly branched isoprenoid (HBI) alkanes suggests a significant upwelling component in the source rock depositional environment. In addition, the high oleanane indices (oleanane/hopane) of the oils are not paralleled in any alternative source rock candidate in this study. The values are as expected for Tertiary source rocks and are at levels that exceed any reported Cretaceous or older source rock or oil. This result, in concert with high nordiacholestane ratios, norcholestane ratios, and HBI concentrations, indicates a Tertiary age source rock.Possible source rocks were selected and analyzed from different outcrops and wells and compared with the oils. A negative correlation suggests that Upper Cretaceous intervals of limestone, marl, and black shale previously believed to be important source rocks can be discounted as an important contributor to Talara basin oils. Instead, the new data suggest a Tertiary source rock (Eocene–Oligocene) comparable to that of the Progreso basin. However, no such source rock strata have yet been identified within the Talara basin. Certain Upper Cretaceous samples with good source potential could support another petroleum system not yet identified in the coastal areas of Peru.Andrea Fildani is a research geologist for the Quantitative Stratigraphy Team in San Ramon. He received his Laurea in geology from the University of Rome “La Sapienza” and his Ph.D. in geological sciences from Stanford University. His research interests are in sequence stratigraphy, seismic stratigraphy, marine geology, and basin analysis. Andrea is currently working on deep-water depositional systems reservoir characterization.Andrew Hanson received his Ph.D. in geological science from Stanford University in 1999. He then worked for Texaco's deep-water Nigeria exploration team as an exploration geoscientist. Hanson is an assistant professor at the University of Nevada, Las Vegas, where his research focuses on China oil and source rock geochemistry, hydrocarbon migration issues associated with salt structures in the La Popa basin of Mexico, and extensional basins of central and southern Nevada. Zhengzheng Chen joined Upstream Technology of ConocoPhillips in 2005. Currently, her work focuses on reservoir geochemistry in heavy-oil fields in Venezuela and Alaska. She received her Ph.D. in organic geochemistry from Stanford University in 2004. Her thesis topics cover biomarker isotopes, characterizing biodegradation using biomarker acids, and petroleum systems in Saudi Arabia. J. Michael Moldowan attained a Ph.D. in chemistry from the University of Michigan. After a postdoctoral fellowship at Stanford University, he joined Chevron in 1974, where he developed fundamental and applied technology related to petroleum biomarkers. Since 1993, Michael has been a professor (research) in Stanford University's Department of Geological and Environmental Sciences. He has published more than 90 articles in scientific journal and four books. Steve Graham is a professor in the School of Earth Sciences, Stanford University. He teaches courses in sedimentary geology, seismic interpretation, sedimentary basin analysis, and petroleum reservoir characterization. His current research projects include studies of sedimentary basins in eastern Asia, South America, and western United States, as well as studies of the sedimentology and str

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