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EEMS2015 organizing committee
Published in Yeping Wang, Jianhua Zhao, Advances in Energy, Environment and Materials Science, 2018
sterane; the ratio of rearranged sterane to regu- lar sterane can serve as maturity parameter, and sterane isomerization parameters C29/( ) and C2920R/20(R S) are used to judge oil and gas maturity. As maturity increases during thermal evolution, the ratio increases gradually (Aboul- Kassin et al, 1996).
Petroleum Geochemical Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
Two examples of common biochemical markers found in petroleum are ‘sterane’ and ‘hopane’ hydrocarbons. Sterane is high molecular weight four cyclic compound derived from steroid or sterol. Hopane is also high molecular compound derived from triterpene.
Origin and depositional environment of oils and sediments in the Cretaceous Deep-Water Tano Basin, Ghana: Constraints from biomarkers
Published in Petroleum Science and Technology, 2022
Rabiatu Abubakar, Kofi Adomako-Ansah, Solomon Adjei Marfo, Judith Ampomah Owusu, Clifford Fenyi
The distribution of regular sterane (C27–C29) is illustrated by chromatograms (Figure 9). The sterane biomarkers are essential because sterols are compounds discovered in algal and higher plants but not in prokaryotic organisms (Mohialdeen et al. 2015) and are used to distinguish between source environments of organic matter. According to Huang and Meinschein (1979), the presence of C27 steranes suggests that the organic matter was derived from algae, whereas a prevalence of C29 steranes demonstrates that the organic matter originated from a higher plant. Low C28 levels are common in limnic environments (Volkman 1986). The majority of the basin’s representative samples are a majority of C27 regular steranes in comparison to C28 and C29 steranes (Figure 9). The regular steranes (C27–C28–C29) distribution depicts that the oils are derived from organic matter, which is a mixture of planktonic and terrestrial plants that have accumulated in a marine environment (Figures 10 and 11). This is in agreement with the results from the cross plots of Pr/n-C17 versus Ph/n-C18 (Figure 5).
The application of sterane in the oil-sources correlation of near-source and multi-source: a case study of CH-8 oil reservoir in Central Ordos Basin, China
Published in Petroleum Science and Technology, 2019
Weiwei Mou, Zhongyi Zhang, Shixiang Li, Cancan Yan, Ruiliang Guo, Jiaqiang Zhang, Shutong Li
During the evolution of sterane compounds, chiral carbon atoms undergo configuration transformation from type R of biological configuration to type S of geological configuration. 14,17 (H) of regular sterane changes from αα to ββ (Dai et al. 2000), so the maturity of crude oil and source rock can be studied by the relative content of sterane compounds in different configurations. This study selected the ration of C2920S/(20S + 20R) to C29ββ/(αα + ββ) as the maturity index. Based on the maturity criterion (Huang et al. 1990), the CH-7, CH-9, CH-10 source rock and CH-8 crude oil have reached the mature stage (Figure 5b).
Organic geochemical characteristics of the upper Triassic source rocks in the Eastern Ordos Basin, China
Published in Petroleum Science and Technology, 2018
Airong Li, Yubin Bai, Shuai Yin
Biomarker compound parameters can reflect the maturity of organic matter. Commonly used sterane biomarker compounds mainly include αααC2920S/(20S + 20R), C29ββ/(ββ + αα), and C31hopanes22S/22R + 22S. The equilibrium point of the αααC2920S/(20S + 20R) parameter is between 0.52 and 0.55, and the corresponding Ro value is about 0.8%. The equilibrium point of C29ββ/(ββ + αα) is between 0.67 and 0.71, the corresponding Ro value is about 0.9%, and the ratio of entering the early stage of oil production is about 0.25 (Peters & Moldowan 1993). The equilibrium point of the C31hopanes22S/22R + 22S parameter is between 0.57 and 0.60. When the C31hopanes22S/22R + 22S is between 0.50 and 0.54, it means that it has just entered the oil generation stage; when the ratio is between 0.57 and 0.62, it means that it has reached or exceeded the main oil production stage (Peters & Moldowan 1993). The C29ββ/(ββ + αα) and αααC2920S/(20S + 20R) values of the Chang 7 samples have reached the equilibrium point (Table 3), indicating that the maturity of the source rock may be about 0.8%. The values of C29ββ/(ββ + αα) of all the samples are greater than 0.25, and the C31hopanes22S/22R + 22S values of the samples except the Chang 7 layer had reached the equilibrium point. Therefore, in addition to the Chang 1 outcrop source rock sample, the other source rock formations all have reached maturity. The C27-C28-C29αααR configuration of the Chang 1 outcrop and the Chang 7 dark mudstone have “V”-shaped distribution (Figure 2), and the other layers mainly have “L”-type distribution, reflecting that they have different parental sources.