Biomarker Composition of Some Oil Seeps from West Sulawesi, Indonesia

Abstract

A 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/C 30 H), medium to high ratio of norhopane/hopane (C 29 /C 30), and medium to high abundant land plan marker such as resin bicadinanes(Bic/C 30 H) and oleananes (Ol/ C 30 H). 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.

Aliphatic Biomarker Signatures of Crude Oil from Tarakan Subbasin, Tarakan Basin, North Kalimantan, Indonesia

“…The presence of hydrocarbon information was needed for the reactivation of wells. The level of maturity and type of organic resources impacted the presence of hydrocarbon and productivity of rock sources (Peters and Fowler, 2002;Sutadiwiria et al, 2018;Hu et al, 2019). The studies of biomarker show that a good hydrocarbon source comes from higher plants.…”

“…The studies of organic geochemical of hydrocarbon aliphatic fraction had been reported to identify the source of organic matter, depositional environment, and thermal maturity of petroleum (Ahmed et al, 2009;Al-Atta et al, 2014;Xiao et al, 2019). The biomarkers such as alkane, isoprenoid, terpane, and sterane are included in aliphatic hydrocarbon group on petroleum source (Peters et al, 2005;El Nady et al, 2014;Onojake et al, 2015;Sutadiwiria et al, 2018). The degree of biodegradation in the reservoir is detected through the loss of n-alkanes, isoprenoids, terpane, and sterane during the secondary process, and they determine the level of oil maturity (Peters et al, 2005).…”

“…done by comparing the mass spectrum obtained and the mass spectrum that has been published by previous researchers (Seifert and Maldowan, 1978;Philp, 1985;Wang and Simoneit, 1990;Lu and Kaplan, 1992;Chattopadhyay and Dutta, 2014;Jiang and George, 2018;Sutadiwiria et al, 2018). The six peaks in the fragmentogram are identified as cis-cis-trans-bicadinane; trans-transtrans-bicadinane; C 30 triterpane; 17α(H)-21β(H)norhopane; 18α(H)-oleanane and 17α (H)-21β (H)-hopane with the most dominant compound is 17α(H)-21β (H)-hopane (Figure 5).…”

Perbandingan Kematangan Antara Sumur Lys Dan Kys Di Daratan Sulawesi Barat Berdasarkan Analisis Geokimia

“…This region is part of an area in Late Mesozoic. West Sulawesi was overlapped by sequence of tertiary, carbonate, and volcaniclastic due to the complex tectonic influences when interactions occured between Australia-India, Pacific, and Southeast Asia micro plates (Sutadiwiria et al, 2018). Western Sulawesi is considered to be the easternmost edge of the Sunda Craton.…”

“…The Budung-budung Formation (Middle Eocene -Late Oligocene) is a sequence of shaly mudstones, quartzose sandstones, limestones, and minor conglomerates, with approximately thickness of 1,000-2,000 m. This formation is overlain unconformable on Late Cretaceous rocks (Calvert and Hall, 2003). It can be seen in the Karama and Lariang regions (Sutadiwiria et al, 2018). The Lisu Formation (Early Miocene -Early Pliocene) is a sequence of interbedded mudstones, greywackes, and pebbly greywackes, with the thikness of 2,000 m (Calvert and Hall, 2003).…”