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Biomarker Distribution (biomarker + distribution)
Selected AbstractsSOURCE ROCK EVALUATION AND GEOCHEMISTRY OF CONDENSATES AND NATURAL GASES, OFFSHORE NILE DELTA, EGYPTJOURNAL OF PETROLEUM GEOLOGY, Issue 2 2003L. M. Sharaf Geochemical analyses of mudstones from wells in the NE offshore Nile Delta suggest that the Early Miocene Qantara Formation has "good" potential to generate hydrocarbons at the studied locations. Its generating capability and oil-proneness increase northwards, towards areas where better organic-matter preservation and a greater contribution from marine source material can be expected. By contrast, the Middle Miocene Sidi Salem Formation has "poor to fair" potential to generate mixed gas and oil, while the overlying Wakar and Kafr El Sheikh Formations have "poor" capability to generate gas with minor oil. Based on pyrolysis Tmax and thermal alteration index assessments, the Wakar and Kafr El Sheikh Formations are immature in the study area. The Sidi Salem and Qantara Formations are immature in the southern part of the study area, but are within the oil window in the north, around well Temsah-4. Biomarker distributions based on GC-MS analyses of two condensate samples from the Wakar and Sidi Salem Formations indicate that hydrocarbons are derived from siliciclastic source rocks containing significant terrestrial material and limited marine organic matter. The condensates were generated during early maturation of Type III kerogen from deeper and more mature source rocks than those encountered in the drilled wells. Geochemical and isotopic data from natural gas produced from the Kafr El Sheikh Formation suggest mixed biogenic and thermogenic sources. [source] FILLING HISTORY OF THE MAUI B FIELD, NEW ZEALAND: NEW INFORMATION FROM OIL INCLUSIONS IN AUTHIGENIC MINERALS FROM THE OIL LEG IN THE MAUI-B1 WELL F SANDSJOURNAL OF PETROLEUM GEOLOGY, Issue 3 2009S. D. Killops A study of the molecular composition of oil inclusions in the Maui field, Taranaki Basin, New Zealand, reveals compositional variation in oil during the filling history of the Paleocene reservoir. The homogenization temperatures of aqueous inclusions in quartz suggest that oil in genetically associated inclusions first reached the proto-Maui structure about 7.0,7.5 Ma ago, and that an effective trap was present at the Paleocene F-sands level, given the abundant oil inclusions. This date coincides with what is believed to represent the early stages of structural development of the trap. The Maui or Pihama sub-basin appears the most likely kitchen for this early charge. The quartz-included oil exhibits a biomarker distribution with a slightly more marine-influenced signature than an oil stain from the same core plug, oil included in authigenic feldspar, and oil-production samples from the overlying Eocene D sands as well as the F sands. The greater similarity of the feldspar-included oil to the production oils together with its possibly slightly lower maturity suggest that the feldspar inclusions formed later than the quartz inclusions. Otherwise, all oil samples examined (inclusion oil, oil / bitumen in sandstones and producible oil) are of similar maturity. [source] Source Rocks for the Giant Puguang Gas Field Sichuan Basin: Implication for Petroleum Exploration in Marine Sequences in South ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2008ZOU Huayao Abstract: Detailed geochemistry studies were conducted to investigate the origin of solid bitumens and hydrocarbon gases in the giant Puguang gas field. Two types of solid bitumens were recognized: low sulfur content, low reflectance (LSLR) solid bitumens in sandstone reservoirs in the Xujiahe Formation and high sulfur content, high reflectance (HSHR) solid bitumens in the carbonate reservoirs in the Lower Triassic Feixianguan and Upper Permian Changxing formations. Solid bitumens in the Upper Triassic Xujiahe Formation correlate well with extracts from the Upper Triassic to Jurassic nonmarine source rocks in isotopic composition of the saturated and aromatic fractions and biomarker distribution. Solid bitumens in the Feixianguan and Changxing formations are distinctly different from extracts from the Cambrian and Silurian rocks but display reasonable correlation with extracts from the Upper Permian source rocks both in isotopic composition of the saturated and aromatic fractions and in biomarker distribution, suggesting that the Permian especially the Upper Permian Longtan Formation was the main source of solid bitumens in the carbonate reservoirs in the Feixianguan and Changxing formations in the Puguang gas field. Chemical and isotopic composition of natural gases indicates that the majority of hydrocarbon gases originated from sapropelic organic matter and was the products of thermal cracking of accumulated oils. This study indicates that source rock dominated by sapropelic organic matter existed in the Upper Permian and had made major contribution to the giant Puguang gas field, which has important implication for petroleum exploration in marine sequences in South China. [source] FROM SUSA TO ANURADHAPURA: RECONSTRUCTING ASPECTS OF TRADE AND EXCHANGE IN BITUMEN-COATED CERAMIC VESSELS BETWEEN IRAN AND SRI LANKA FROM THE THIRD TO THE NINTH CENTURIES AD*ARCHAEOMETRY, Issue 3 2008B. STERN In contrast with artefactual studies of long-distance trade and exchange in South Asia during the Prehistoric and Early Historic periods (Ardika et al. 1993; Gogte 1997; Krishnan and Coningham 1997; Tomber 2000; Gupta et al. 2001; Ford et al. 2005), few scientifically orientated analyses have focused on artefacts from the region's Historic period. During excavations at the ancient city of Anuradhapura, Sri Lanka, a number of buff ware ceramics with a putative organic coating on the interior were recovered (Coningham 2006). Dated stylistically to between the third and ninth centuries ad, analysis of the coatings using gas chromatography,mass spectrometry (GC,MS) and stable isotope analysis (carbon and deuterium) confirmed that the coatings are bitumen,an organic product associated with petroleum deposits. There are no known bitumen sources in Sri Lanka, and biomarker distributions and isotopic signatures suggest that the majority of the samples appear to have come from a single bitumen source near Susa in Iran. The relationship between the bitumen coatings and the vessels is discussed, and it is suggested that the coatings were used to seal permeable ceramic containers to allow them to transport liquid commodities. This study enhances our knowledge of networks of trade and exchange between Sri Lanka and western Asia during Historic times. [source] | ||||||||||