Geochemistry of severely biodegraded oils in the Carboniferous volcanic reservoir of the Chepaizi Uplift, Junggar Basin, NW China

A substantial amount of petroleum was recently discovered in the Carboniferous volcanic reservoir of the Chepaizi Uplift in the western Junggar Basin, yet the source is still indefinitive. Geochemical investigation indicates that the Carboniferous oils from the eastern and western Chepaizi Uplift are characterized by different source facies, although they are all typically of lacustrine origin. The eastern oils exhibit a restricted, clastic starved, highly reducing hypersaline condition during source rock deposition, which is distinct from the western oils. The Carboniferous oils were subjected to biodegradation ranging from rank 6 to rank 9, as indicated by the presence of 25-norhopane, evident depletion of hopanes and regular steranes, and even selective reduction of tricyclic terpanes. The maturities for the Carboniferous oils correspond to the onset of oil generation. The eastern oils contain lower (C19 + C20)TT/(C23 + C24)TT and C19TT/C21TT, and lighter stable carbon isotopes than the western ones, correlating well with the Middle Permian Wuerhe (P2w) source rocks and the Jurassic source rocks, respectively. The good correlation of tricyclic terpanes source-related parameters further implies less contribution to the eastern oils by the Carboniferous source rocks.

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A GEOCHEMICAL INVESTIGATION OF OILS AND SOURCE ROCKS FROM THE SURAT BASIN

The APPEA Journal ◽

10.1071/aj85017 ◽

1986 ◽

Vol 26 (1) ◽

pp. 172 ◽

Cited By ~ 1

Author(s):

R. P. Philp ◽

T. D. Gilbert

Keyword(s):

Land Plant ◽

Source Material ◽

Source Rocks ◽

Potential Source ◽

Oil Generation ◽

Formation History ◽

Tentative Evidence ◽

Geochemical Analyses ◽

Geochemical Investigation ◽

Migration Parameter

A series of twelve oils and five source rocks and potential source rocks from the Surat Basin have been subjected to detailed geochemical analyses. Particular attention has been given to determining the distribution of various classes of biomarkers such as the steranes and triterpanes. The results from this study have shown that the Cabawin oil is derived from the Permian Back Creek Formation and has a high content of marine organic source material. The Triassic/Jurassic oils have a different source from the Cabawin oil and are dominated by land plant source material. Within the Triassic/Jurassic oils there are subtle variations in biomarker distributions suggesting that some oils may have small but additional amounts of different source materials. A number of Cretaceous and Jurassic potential source rocks (i.e. Walloon) have biomarker parameters clearly indicating levels of maturity at which oil generation is impossible.A number of the oils in this basin are extensively biodegraded. In particular biodegradation has been very heavy in the Riverslea/Yapunyah area. With the exception of Conloi oil, all the oils appear to have been exposed to similar levels of maturity. A biomarker migration parameter has provided some tentative evidence to suggest that, in general, oils in the southern part of the basin have migrated further than those in the northern part.In summary, the biomarker data from oils and source rocks of the Surat Basin have been used to provide a new insight into the origin of the Surat Basin oils and their post-formation history.

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Investigation on the biodegradation levels of super heavy oils by parameter-striping method and refined Manco scale: a case study from the Chepaizi Uplift of Junggar Basin

Petroleum Science ◽

10.1007/s12182-020-00542-x ◽

2021 ◽

Author(s):

Xiang-Chun Chang ◽

Bing-Bing Shi ◽

Zhong-Quan Liu ◽

Yue Wang ◽

You-De Xu

Keyword(s):

Refractory Compound ◽

Junggar Basin ◽

Heavy Oils ◽

Volcanic Reservoir ◽

Stripping Method ◽

Magnitude Variation ◽

Absolute Concentrations ◽

Oil Density ◽

Tricyclic Terpanes

AbstractThe Carboniferous volcanic reservoir in the Chepaizi Uplift became an exploration hot target in recent years for its substantial amount of oils discovered. However, most of the Carboniferous heavy oils were biodegraded to PM7 or higher with orders of magnitude variation in oil viscosities. Two oil groups (I and II) exactly corresponding to the western and eastern Chepaizi Uplift were distinguished according to their source diagnose. Furthermore, three oil families (II1, II2 and II3), with the biodegradation level of PM7, PM8–8+, PM9+, respectively, were classified based on molecular compositions and parameter-stripping method of strongly bioresistant parameters. Allowing for this extremely high biodegradation case, more biodegradation refractory compound class were added to establish a refined Manco scale to quantitatively evaluate the biodegradation extent. Refined Manco number (RMN2) positively correlated with the oil density, NSO contents, and absolute concentrations of diasteranes and gammacerane, negatively correlated with the absolute concentrations of diahopane, summed tricyclic terpanes and pentacyclic terpanes. This refined scale showed higher resolution than the PM one to differentiate the biodegradation extent of Carboniferous heavy oils from the Chepaizi Uplift, especially those with same PM values but different oil viscosities.

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Small angle neutron scattering signature of oil generation in artificially and naturally matured hydrocarbon source rocks

Organic Geochemistry ◽

10.1016/s0146-6380(99)00128-x ◽

2000 ◽

Vol 31 (1) ◽

pp. 1-14 ◽

Cited By ~ 61

Author(s):

A.P. Radliński ◽

C.J. Boreham ◽

P. Lindner ◽

O. Randl ◽

G.D. Wignall ◽

...

Keyword(s):

Neutron Scattering ◽

Small Angle ◽

Small Angle Neutron Scattering ◽

Source Rocks ◽

Hydrocarbon Source Rocks ◽

Oil Generation

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Origin and migration pathway of biodegraded oils pooled in multiple-reservoirs of the Chepaizi Uplift, Junggar Basin, NW China: Insights from geochemical characterization and chemometrics methods

Marine and Petroleum Geology ◽

10.1016/j.marpetgeo.2020.104655 ◽

2020 ◽

Vol 122 ◽

pp. 104655 ◽

Cited By ~ 1

Author(s):

Bingbing Shi ◽

Xiangchun Chang ◽

Youde Xu ◽

Yongrui Wang ◽

Lixin Mao ◽

...

Keyword(s):

Junggar Basin ◽

Nw China ◽

Geochemical Characterization ◽

Migration Pathway ◽

Biodegraded Oils ◽

And Migration

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Organic petrology and hydrocarbon generation of potential source rocks in Permian formation of Junggar Basin, Northwest in China

Journal of Central South University ◽

10.1007/s11771-013-1662-0 ◽

2013 ◽

Vol 20 (6) ◽

pp. 1693-1702 ◽

Cited By ~ 4

Author(s):

Li-ming Qin ◽

Zhi-huan Zhang

Keyword(s):

Junggar Basin ◽

Source Rocks ◽

Hydrocarbon Generation ◽

Organic Petrology ◽

Potential Source

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Feldspar Dissolution and Its Influence on Reservoirs: A Case Study of the Lower Triassic Baikouquan Formation in the Northwest Margin of the Junggar Basin, China

Geofluids ◽

10.1155/2018/6536419 ◽

2018 ◽

Vol 2018 ◽

pp. 1-19 ◽

Cited By ~ 1

Author(s):

Meng Xiao ◽

Xuanjun Yuan ◽

Dawei Cheng ◽

Songtao Wu ◽

Zhenglin Cao ◽

...

Keyword(s):

Clay Minerals ◽

Physical Property ◽

Junggar Basin ◽

Sedimentary Facies ◽

Lower Triassic ◽

Depositional Environments ◽

Source Rocks ◽

Reservoir Quality ◽

Delta Plain ◽

Feldspar Dissolution

Feldspar dissolution is a common feature in clastic rock reservoirs of petroliferous basins and has an important influence on reservoir quality. However, the effect of feldspar dissolution on reservoir quality varies under different depositional environments and diagenetic systems. The study area in this paper is located in the Baikouquan Formation in the northwestern margin of the Junggar Basin, which is significantly influenced by feldspar dissolution. Based on the analyses of core and thin section observations, QEMSEM, XRD, SEM, CL, fluorescence, and image analysis software combined with logging and physical property data, this study shows that feldspar dissolution in the subaqueous distributary channel of a fan delta plain, which has good original physical properties and low mud contents, significantly improves the properties of the reservoir. The main reasons for this are as follows: (1) the sedimentary facies with good original properties and low mud content is a relatively open system in the burial stage. The acidic fluids needed for feldspar dissolution are mostly derived from organic acids associated with the source rocks and migrate to the good-permeability area of the reservoir; (2) the by-products of feldspar dissolution, such as authigenic clay minerals and authigenic quartz, are transported by pore water in a relatively open diagenetic system and then precipitated in a relatively closed diagenetic system; and (3) the clay minerals produced by feldspar dissolution in different diagenetic environments and diagenetic stages have different effects on the reservoir. When the kaolinite content is less than 3%, the illite content is less than 4%, and the chlorite content is less than 12%, the clay minerals have a positive effect on the porosity. These clay minerals can reduce porosity and block pore throats when their contents are larger than these values.

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Oil generation from coal source rocks: the influence of depositional conditions and stratigraphic age

Geological Survey of Denmark and Greenland Bulletin ◽

10.34194/geusb.v7.4822 ◽

2005 ◽

Vol 7 ◽

pp. 9-12 ◽

Cited By ~ 6

Author(s):

Henrik I. Petersen

Keyword(s):

North Sea ◽

Liquid Hydrocarbon ◽

Source Rocks ◽

Hydrocarbon Generation ◽

Oil Generation ◽

Generation Capacity ◽

The Subject ◽

Coal Composition ◽

Gippsland Basin ◽

Australasian Region

Although it was for many years believed that coals could not act as source rocks for commercial oil accumulations, it is today generally accepted that coals can indeed generate and expel commercial quantities of oil. While hydrocarbon generation from coals is less well understood than for marine and lacustrine source rocks, liquid hydrocarbon generation from coals and coaly source rocks is now known from many parts of the world, especially in the Australasian region (MacGregor 1994; Todd et al. 1997). Most of the known large oil accumulations derived from coaly source rocks have been generated from Cenozoic coals, such as in the Gippsland Basin (Australia), the Taranaki Basin (New Zealand), and the Kutei Basin (Indonesia). Permian and Jurassic coal-sourced oils are known from, respectively, the Cooper Basin (Australia) and the Danish North Sea, but in general only minor quantities of oil appear to be related to coals of Permian and Jurassic age. In contrast, Carboniferous coals are only associated with gas, as demonstrated for example by the large gas deposits in the southern North Sea and The Netherlands. Overall, the oil generation capacity of coals seems to increase from the Carboniferous to the Cenozoic. This suggests a relationship to the evolution of more complex higher land plants through time, such that the highly diversified Cenozoic plant communities in particular have the potential to produce oil-prone coals. In addition to this overall vegetational factor, the depositional conditions of the precursor mires influenced the generation potential. The various aspects of oil generation from coals have been the focus of research at the Geological Survey of Denmark and Greenland (GEUS) for several years, and recently a worldwide database consisting of more than 500 coals has been the subject of a detailed study that aims to describe the oil window and the generation potential of coals as a function of coal composition and age.

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RETRACTED ARTICLE: Light hydrocarbon geochemistry: insight into oils/condensates families and inferred source rocks of the Woodford–Mississippian tight oil play in North-Central Oklahoma, USA

Petroleum Science ◽

10.1007/s12182-020-00441-1 ◽

2020 ◽

Vol 17 (3) ◽

pp. 582-597 ◽

Cited By ~ 1

Author(s):

Ting Wang ◽

Dong-Lin Zhang ◽

Xiao-Yong Yang ◽

Jing-Qian Xu ◽

Coffey Matthew ◽

...

Keyword(s):

High Performance ◽

Light Hydrocarbon ◽

Source Rocks ◽

Variable Degree ◽

Woodford Shale ◽

Anadarko Basin ◽

Geochemical Parameters ◽

Retracted Article ◽

Geochemical Fingerprint ◽

Geochemical Investigation

AbstractThe Woodford–Mississippian “Commingled Production” is a prolific unconventional hydrocarbon play in Oklahoma, USA. The tight reservoirs feature variations in produced fluid chemistry usually explained by different possible source rocks. Such chemical variations are regularly obtained from bulk, molecular, and isotopic characteristics. In this study, we present a new geochemical investigation of gasoline range hydrocarbons, biomarkers, and diamondoids in oils from Mississippian carbonate and Woodford Shale. A set of oil/condensate samples were examined using high-performance gas chromatography and mass spectrometry. The result of the condensates from the Anadarko Basin shows a distinct geochemical fingerprint reflected in light hydrocarbon characterized by heptane star diagrams, convinced by biomarker characteristics and diamantane isomeric distributions. Two possible source rocks were identified, the Woodford Shale and Mississippian mudrocks, with a variable degree of mixing. Thermal maturity based on light hydrocarbon parameters indicates that condensates from the Anadarko Basin are of the highest maturity, followed by “Old” Woodford-sourced oils and central Oklahoma tight oils. These geochemical parameters shed light on petroleum migration within Devonian–Mississippian petroleum systems and mitigate geological risk in exploring and developing petroleum reservoirs.

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