The Occurrence of Extended Tricyclic Terpanes in the Proterozoic and Paleozoic

A widespread charge system for oil accumulation in the offshore northern Perth Basin, Western Australia, is revealed by specialised fluid inclusion technologies. Palaeo-oil columns are detected in about three of four exploration wells, including those at the Cliff Head, Dunsborough, Frankland and Perseverance fields, and in dry wells at Flying Foam–1, Hadda–1, Houtman–1, Leander Reef–1, Lilac–1, Livet–1, Mentelle–1 and Morangie–1. A high incidence of palaeo-oil charge into Permian reservoirs below the Kockatea Shale confirms that the conventional oil shows are, in part, residues of palaeo-oil. Oil migration is suggested at Vindara–1 and Leander Reef–1 and is below detection limits in Batavia–1, Charon–1, Fiddich–1 Geelvink–1A, Gun Island–1 and South Turtle Dove–1B, Twin Lions–1 and Wittecarra–1. New geochemical data from fluid inclusion oil at Hadda–1 shows evidence for a contribution from the Hovea Member of the Kockatea Shale, including: high wax content; low pristane/phytane ratio; high abundance of extended tricyclic terpanes; and, the highly diagnostic C33 n-alkylcyclohexane biomarker. This key component of the petroleum system acted as both source and seal, and extends further offshore than previously realised. Possible co-sourcing from terrestrial organic matter is indicated by high abundances of C29 steranes and diasteranes, C19 tricyclic, and C24 tetracyclic terpanes, which may be sourced from Permian rocks. The high incidence of palaeo-oil and residual columns suggests that trap integrity is likely to be an important preservation risk, with elements of gas displacement. Screening of prospects for structural and hydrocarbon charge characteristics, which are favourable for retention of oil, is key in future exploration of the offshore northern Perth Basin.

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Biomarker Molecular Indicators Predict Biodegraded Heavy Oil Physical Properties: A Case from Dongying Depression, Eastern China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.524-527.2069 ◽

2012 ◽

Vol 524-527 ◽

pp. 2069-2073

Author(s):

Zhong Hong Chen

Keyword(s):

Physical Properties ◽

Eastern China ◽

Bohai Bay ◽

Thermal Maturity ◽

Dongying Depression ◽

Wide Range ◽

Biodegraded Oils ◽

Tricyclic Terpanes ◽

Molecular Indicators ◽

Maturity Parameters

To determine reliable molecular thermal maturity parameters for prediction of the physical properties of biodegraded oils, a suite of oils including 11 biodegraded oils from Caoqiao oilfield and 5 non-biodegraded oils from Wangjiagang oilfield in Dongying depression in Bohai-bay basin, eastern of China were analyzed. The oils were selected in a wide range of viscosity in order to investigate the relation between the parameters and oil properties. The data show the effects of biodegradation on some molecular thermal maturity parameters: C29 sterane parameters C2920S/(20S+20R) and C29ββ/(ββ+αα) increased apparently under heavy biodegradation (rank 6~7); parameters C3122S/(22S+22R), C3222S/(22S+22R), C293-methyl/C29 4-methyl, (C28+C29Tricyclics)/Ts and (C28+C29Tricyclics)/ (C28+C29Tricyclics +Ts) showed effects from heavy biodegradation (rank 6~7), and terpanes parameters Ts/(Ts+Tm), C29Ts/(C29Ts+C29Tm) and aromatic C20/(C28+C20), (C20+C21)/(C20+C21+C26+C27+C28) and D(3-6)/(D3-6+ C29 4-methylstigmastane 20R showed no effect from heavy biodegradation. Based on the comparison, the molecular maturity parameters C26 to C28 triaromatic parameters C26S/ (C26S+C28S), C27R/(C27R+C28R), C28/(C26+C27+C28) and tricyclic terpanes parameters C19/(C19+C23) were recommended to predict the physical properties of biodegraded oil for these parameters showed no effects from biodegradation(rank 6~7) and better relations with oil physical properties compared to other parameters. Some quantificational equations between these molecular thermal maturity parameters and the physical properties of biodegraded oils were inferred, which may assist in predicting the viscosity and API gravity of reservoired oils before production.

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Mass spectral characteristics of C19 and C20 tricyclic terpanes detected in Latrobe Tasmanite oil shale

European Journal of Mass Spectrometry ◽

10.1255/ejms.278 ◽

1999 ◽

Vol 5 (1) ◽

pp. 221 ◽

Cited By ~ 10

Author(s):

Paul Greenwood ◽

Simon George

Keyword(s):

Oil Shale ◽

Spectral Characteristics ◽

Mass Spectral ◽

Tricyclic Terpanes

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Extended Tricyclic Terpanes: Molecular Markers in Lower Jurassic Synrift Lacustrine Black Mudstones of the Hartford Basin, Connecticut: ABSTRACT

AAPG Bulletin ◽

10.1306/703c9feb-1707-11d7-8645000102c1865d ◽

1989 ◽

Vol 73 ◽

Author(s):

Michael A. Kruge, John F. Hubert, J

Keyword(s):

Molecular Markers ◽

Lower Jurassic ◽

Tricyclic Terpanes

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Identification of an extended series of tricyclic terpanes in petroleum

Geochimica et Cosmochimica Acta ◽

10.1016/0016-7037(83)90313-7 ◽

1983 ◽

Vol 47 (8) ◽

pp. 1531-1534 ◽

Cited By ~ 96

Author(s):

J.Michael Moldowan ◽

Wolfgang K. Seifert ◽

Emilio J. Gallegos

Keyword(s):

Tricyclic Terpanes

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Organic geochemical characteristics and comparison of the source rocks and the severely biodegradable oil sands around Karamay, China

Energy Exploration & Exploitation ◽

10.1177/0144598720964879 ◽

2020 ◽

pp. 014459872096487

Author(s):

Chong Feng ◽

Wenjun He ◽

Hua Cai ◽

Jingyuan Zhang ◽

Yinlan Nie

Keyword(s):

Organic Carbon ◽

Oil Sands ◽

Geochemical Characteristics ◽

Source Rocks ◽

Gas Chromatography Mass Spectrometry ◽

Mature Stage ◽

Oil Sand ◽

Core Samples ◽

Tricyclic Terpanes ◽

Almost All

For the sake of explaining the organic geochemical characteristics of the hydrocarbon source rocks (SRs) around Karamay, such as thermal maturity (TM) (evidences from the temperature of maximum pyrolysis yield (Tmax), the Carbon Preference Index (CPI) and Odd to Even Preference (OEP) values, the C30 M/H versus Tm/Ts, the C29 ββ/(ββ + αα) versus C29 20 S/(20 S + 20 R)), hydrocarbon potential (HP) (evidences from total organic carbon (TOC) and rock pyrolysis (RP)), organic matter (OM) source input (evidences from n-Alkane distribution, the relative quantity of C27-C28-C29 steranes, the (C19 + C20)/C23 tricyclic terpane (TT), and the Terrigenous/aquatic ratio (TAR)) as well as paleoenvironment (evidences from the pristane/phytane (Pr/Ph) and the Gammacerane index), and in order to analyze the biodegradation degree and source of oil sand (OS) oil, 55 core samples of SRs in all were selected to measure TOC and RP. 14 core samples of SRs and 3 OS samples were selected for gas chromatography–mass spectrometry (GC-MS) analysis. 11 core samples of SRs and 3 OS samples were used for organic carbon isotope (OCI) analysis. The results indicate that except the SR from Fengcheng formation (P1 f) which is in the stage of high or over evolution, the other SRs are in mature stage. OM type of Carboniferous (C) SRs are type Ⅱ kerogen, with the largest abundance. OM type of the SRs in Wuerhe formation (P2 w) and Jiamuhe formation (P1 j) are type Ⅲ kerogen with good and medium OM abundances. Almost all SRs were formed in the reduction environment of high salinity, and the main OM source input is the lower aquatic plants. Karamay formation (T2 k) and Badaowan formation (J1 b) oil sands (OSs) around Karamay have undergone serious biodegradation. It is suggested that OS oil are mainly from P1 f SRs (evidences from the tricyclic terpanes (TT), triarysteranes, pregnane, homopregnane and OCI).

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Biomarker distributions and depositional environments of continental source rocks in Sichuan Basin, SW China

Energy Exploration & Exploitation ◽

10.1177/0144598720915533 ◽

2020 ◽

Vol 38 (6) ◽

pp. 2296-2324

Author(s):

Siqin Huang ◽

Guosheng Xu ◽

Fanghao Xu ◽

Wei Wang ◽

Haifeng Yuan ◽

...

Keyword(s):

Sichuan Basin ◽

Lower Jurassic ◽

Upper Triassic ◽

Depositional Environments ◽

Source Rocks ◽

Late Triassic ◽

Ms Analysis ◽

Continental Source ◽

The Sichuan Basin ◽

Tricyclic Terpanes

In order to study the distributions of the biomarker of the continental source rocks in the Sichuan Basin, 71 source rock samples were collected from the Upper Triassic-Lower Jurassic strata in different regions. The n-alkanes, isoprenoids, terpane, sterane, sesquiterpenes, caranes and aromatics in the extracts were analyzed in detail. GC-MS analysis has been conducted to analyze the biomarker of the continental source rocks. The results of GC-MS analysis indicate that the Upper Triassic source rocks are high in the content of extended tricyclic terpanes, pristane, phytane, gammacerane, C28 regular sterane and carotene. However, they are low in content of rearranged compounds. The ratio of Pr/Ph is less than 1, with the characteristics of tricyclic terpane C21 > C23. The Lower Jurassic source rocks are extremely low in content (even zero) of extended tricyclic terpanes, pristane, phytane, gammacerane, C28 regular sterane and carotene, and high in content of rearranged compounds. The ratio of Pr/Ph is more than 1, with tricyclic terpane C21 > C23. These characteristics are still preserved after maturation. Moreover, during the sedimentation of the source rocks of T3x2–T3x3 members, the supply of continental plants was low (TAR < 1, with regular sterane C27 > C29, 1-MP/9-MP < 1). The source rocks of T3x5 member were low in salinity (slightly low content of gammacerane and carotene), being different significantly from the other Upper Triassic source rocks. In addition, during the sedimentation of the source rocks of J1dn Member, the supply of continental plants was also low (regular sterane C27 > C29, 1-MP/9-MP < 1), being quite different from that of J1l member. Through analysis of the difference in biomarkers, it is indicated that the sedimentary environment had changed from anoxic and brackish water during the Late Triassic to oxygen-rich and freshwater during the Early Jurassic in the Sichuan Basin. During this process, the types of organic matters had changed for several times.

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