4 research outputs found

    Palaeofacies and biomarker characteristics of Paleogene to Neogene rocks in the Makassar Straits, Indonesia

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    Borehole K-1 is an exploratory well that was drilled in the North Makassar Basin (West Sulawesi) in 2011. Gas chro- matography (GC) and gas chromatography-mass chromatography (GC-MS) analyses have been conducted on extracts from well cuttings from the Paleogene to Neogene interval in order to investigate the characteristics of biomarkers present. Although the well was drilled with oil-based mud and gas chromatographic analysis reveals that the alkane fractions are heavily contaminated, detailed investigation of biomarkers in these rock extracts and comparison with biomarkers in the oil-based mud has revealed that, while there are hopane and sterane biomarkers in the mud, there are also a discrete set of biomarkers that are indigenous to the rocks. These include oleanane, bicadinanes, taraxastane and other higher-plant-derived triterpanes. The presence of these compounds in environments that range from bathyal to marginal marine and even to lacustrine, shows the extent of reworking of terrestrial material into aquatic settings in this region during the Paleogene and Neogene and provides further evidence of a predominance of terrestrial material, even in deep-marine settings, with little ‘in-situ’ material noted. These findings have important implications for the use of biomarkers as indicators of palaeoenvironment in both source rocks and oils

    Biomarker Composition of Some Oil Seeps from West Sulawesi, Indonesia

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    DOI: 10.17014/ijog.5.3.211-220A suite of oil seep samples collected from the Lariang and Karama Basins, West Sulawesi, Indonesia, have been analyzed using GC and GCMS techniques. Their biomarker compositions have been used to reveal the likely source rock that produces oil. These oil seep samples contain a range in both the concentration of hydrocarbons present and certain level of biodegradation experienced. All sterane m/z 217 data display a familiar pattern of steranes with carbon numbers from 27 to 29 together with pregnane and homo-pregnanes, including rearranged steranes. Triterpane (m/z 191) data show a moderate content of tricyclic terpanes (Tri/C30H), medium to high ratio of norhopane/hopane (C29/C30), and medium to high abundant land plan marker such as resin bicadinanes(Bic/C30H) and oleananes (Ol/C30H). The presence of high abundant oleananes in these samples has been interpreted as the evidence for a marine influence during early diagenesis that may occur by marine or via re-deposition of peat organics in marine sediments. Hence, these results state that the organic matter facies for their source rock oil seep samples from the West Sulawesi region are detected as mixed between allochthonous macerals from typical terrestrial higher plants transported into the basin from distal swamps and soils and some marine organic matter.</p

    Palaeofacies and biomarker characteristics of Paleogene to Neogene rocks in the Makassar Straits, Indonesia

    No full text
    Borehole K-1 is an exploratory well that was drilled in the North Makassar Basin (West Sulawesi) in 2011. Gas chromatography (GC) and gas chromatography-mass chromatography (GC-MS) analyses have been conducted on extracts from well cuttings from the Paleogene to Neogene interval in order to investigate the characteristics of biomarkers present. Although the well was drilled with oil-based mud and gas chromatographic analysis reveals that the alkane fractions are heavily contaminated, detailed investigation of biomarkers in these rock extracts and comparison with biomarkers in the oil-based mud has revealed that, while there are hopane and sterane biomarkers in the mud, there are also a discrete set of biomarkers that are indigenous to the rocks. These include oleanane, bicadinanes, taraxastane and other higher-plant-derived triterpanes. The presence of these compounds in environments that range from bathyal to marginal marine and even to lacustrine, shows the extent of reworking of terrestrial material into aquatic settings in this region during the Paleogene and Neogene and provides further evidence of a predominance of terrestrial material, even in deep-marine settings, with little ‘in-situ’ material noted. These findings have important implications for the use of biomarkers as indicators of palaeoenvironment in both source rocks and oils

    Palaeofacies and biomarker characteristics of Paleogene to Neogene rocks in the Makassar Straits, Indonesia

    No full text
    Borehole K-1 is an exploratory well that was drilled in the North Makassar Basin (West Sulawesi) in 2011. Gas chro- matography (GC) and gas chromatography-mass chromatography (GC-MS) analyses have been conducted on extracts from well cuttings from the Paleogene to Neogene interval in order to investigate the characteristics of biomarkers present. Although the well was drilled with oil-based mud and gas chromatographic analysis reveals that the alkane fractions are heavily contaminated, detailed investigation of biomarkers in these rock extracts and comparison with biomarkers in the oil-based mud has revealed that, while there are hopane and sterane biomarkers in the mud, there are also a discrete set of biomarkers that are indigenous to the rocks. These include oleanane, bicadinanes, taraxastane and other higher-plant-derived triterpanes. The presence of these compounds in environments that range from bathyal to marginal marine and even to lacustrine, shows the extent of reworking of terrestrial material into aquatic settings in this region during the Paleogene and Neogene and provides further evidence of a predominance of terrestrial material, even in deep-marine settings, with little ‘in-situ’ material noted. These findings have important implications for the use of biomarkers as indicators of palaeoenvironment in both source rocks and oils
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