Origin of an unusual heavy oil from the Baiyinchagan depression, Erlian basin, northern China

Huang, Haiping; Jin, Guangxi; Lin, Changsong; Zheng, Yabin

doi:10.1016/s0264-8172(03)00038-2

Cited by 27 publications

(11 citation statements)

References 19 publications

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“…From bottom to top, the Cretaceous strata include the Arshan Formation (K 1 a, ~ 250 to 1300 m), the Tengger Formation (K 1 t, ~ 90 to 830 m), the Duhongmu Formation (K 1 d, ~ 220 to 1550 m) and the Saihantala Formation (K 1 s, ~ 0 to 300 m), which comprise mainly dark terrigenous detrital sediments (Fig. 1C) (Huang et al, 2003).…”

Section: Geological Setting and Study Areamentioning

confidence: 99%

Syn‐sedimentary hydrothermal dolomites in a lacustrine rift basin: Petrographic and geochemical evidence from the lower Cretaceous Erlian Basin, Northern China

Yang

Whitaker

et al. 2019

Sedimentology

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Dolomites occur extensively in the lower Cretaceous along syn-sedimentary fault zones of the Baiyinchagan Sag, westernmost Erlian Basin, within a predominantly fluvial-lacustrine sedimentary sequence. Four types of dolomite are identified, associated with hydrothermal minerals such as natrolite, analcime and Fe-bearing magnesite. The finely-crystalline dolomites consist of anhedral to subhedral crystals (2 to 10 μm), evenly commixed with terrigenous sediments that occur either as matrix supporting grains (Fd1) or as massive argillaceous dolostone (Fd2). Medium-crystalline (Md) dolomites are composed of subhedral to euhedral crystals aggregates (50 to 250 μm) and occur in syn-sedimentary deformation laminae/bands. Coarse-crystalline (Cd) dolomites consist of non-planar crystals (mean size >1 mm), and occur as fracture infills crosscutting the other dolomite types. Fd1, Md and Cd dolomites have similar values of δ 18 O (−20.5 to −11.0 ‰ Vienna PeeDee Belemnite) and δ 13 C (+1.4 to +4.5 ‰ Vienna PeeDee Belemnite), but Fd2 dolomites are isotopically distinct (δ 18 O −8.5 to −2.3‰ Vienna PeeDee Belemnite; δ 13 C +1.4‰ to +8.6‰ Vienna PeeDee Belemnite). Samples define three groups which differ in light rare-earth elements vs. high rare-earth elements enrichment/depletion and significance of Tb, Yb and Dy anomalies. Md dolomites have signatures that indicate formation from brines at very high temperature, with salinities of 11.8 to 23.2 eq. wt. % NaCl and T h values of 167 to 283°C. The calculated temperatures of Fd1 and Cd dolomites extend to slightly lower values (141 to 282°C), while Fd2 dolomites are distinctly cooler (81 to 124°C). These results suggest that the dolomites formed from hydrothermal fluid during and/or penecontemporaneous with sediment deposition. Faults and fractures bounding the basin were important conduits through which high-temperature Mg-rich fluids discharged, driven by an abnormally high heat flux associated with local volcanism. It is thought that differing amounts of cooling and degassing of these hydrothermal fluids, and of mixing with lake waters, facilitated the precipitation of dolomite and associated minerals, and resulted in the petrographic and geochemical differences between the dolomites.

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Section: Geological Setting and Study Areamentioning

confidence: 99%

Syn‐sedimentary hydrothermal dolomites in a lacustrine rift basin: Petrographic and geochemical evidence from the lower Cretaceous Erlian Basin, Northern China

Yang

Whitaker

et al. 2019

Sedimentology

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“…The Lower Cretaceous sequence includes the Aershan (K 1 a), Tengger (K 1 t), and Saihantala (K 1 s) formations, which are composed of alluvial, fan deltas, and lacustrine sediments. The Tengger Formation is made up of dark grey‐black mudstones interbedded with sandstones and siltstones, with a thickness of 500–2100 m and can be further subdivided into the lower Tengger Member (K 1 t 1 ) and the upper Tengger Member (K 1 t 2 ) on the basis of its lithology and fossil assemblages (Huang, Jin, Lin, & Zheng, ). Possible source rock horizons exist mainly in the K 1 a and K 1 t 1 formations.…”

Section: Geologic Settingmentioning

confidence: 99%

Relationship between source rock development and petroleum accumulation in the Erlian Basin, northern China

et al. 2018

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The Wuli and Saihan sags in the Erlian Basin, the most petroliferous basin in northern China, were analysed with bulk geochemical analysis, carbon isotopic composition, microthermometry of fluid inclusions, and basin modelling to characterize the organic matter abundance and composition, to construct source rock development models, and to reveal the relationship between source rock development and hydrocarbon accumulation. The samples display wide variations in total organic carbon content and Rock‐Eval indices, suggesting heterogeneity of organic matter richness and type. The Wuli Sag has oxic depositional environment, high productivity, and high total organic carbon content; the effective oil source rocks are mainly distributed in the deep sag where the productivity is high; and there is plenty of organic matter left and preserved after degradation. In the Saihan Sag, there is a small amount of organic matter deposited because of low productivity; the effective oil source rocks are mainly distributed in the slope by the deep sag where the reducing degree is the strongest. The source rock development models controlled the geochemical characteristics and distribution of source rocks, which are the keys to hydrocarbon potential and accumulation. The oil of Wuli Sag is mainly distributed in the deep sag, whereas the oil of Saihan Sag is mainly distributed in the slope by deep sag, which is in agreement with the previously effective oil source rocks distribution. In the strong division sags, the region where source rock distributed is beneficial to hydrocarbon accumulation. The conclusions may have important implications for petroleum exploration in other small lacustrine depositional systems.

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“…Biodegradation is a well-documented process that modifies the physical properties and chemical compositions of reservoir oils (Huang et al 2003). Much work has been done on the formation of heavy oil and solid bitumen via biodegradation in the Tarim Basin (Tian et al 2008;Chang et al 2012;Zhu et al 2012;Zhang et al 2014;Cheng et al 2016).…”

Section: Introductionmentioning

confidence: 99%

“…The effect of water washing can be readily illustrated by laboratory experiments. However, it is a little difficult to assess the extent of water washing for natural oils because it is often associated with biodegradation (Huang et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Geochemistry and origin of Ordovician oils in the Rewapu Block of the Halahatang Oilfield (NW China)

Tang

Fang

et al. 2018

Pet. Sci.

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The oils in the Rewapu Block of the Halahatang Oilfield in the Tarim Basin (northwestern China) were geochemically analyzed by gas chromatography-mass spectrometry to investigate their origin and possible secondary alteration. The physical properties and chemical compositions of these Ordovician oils vary greatly, ranging from light to extremely heavy oils. All these oils belong to one single population and were derived from same source kitchen/bed. The differences in their chemical compositions and physical properties mainly result from secondary alteration of oils that were charged during the early phase of trap formation. The thickness of Upper Ordovician and Silurian caprocks of oil reservoirs in the Rewapu Block is higher than that in the north part of the Halahatang region, and therefore, significant biodegradation process is prevented. Compared to heavy oils in the north part, the Rewapu oils are dominated by light oils with no 25-norhopanes and no GC-MS ''hump'' (UCM: unresolved complex mixture) on the chromatographic baselines. The heavy oils in Wells RP7 and RP101C were primarily influenced by water washing since apparent reduction of alkylated dibenzothiophenes was observed. The local geological background favored the water washing alteration. The reservoir geochemical study has practical application in hydrocarbon exploration and predicts the nature of oils in this oilfield. Keywords Biodegradation Á Water washing Á Oil charging process Á Ordovician Á Tarim Basin Edited by Jie Hao

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Origin of an unusual heavy oil from the Baiyinchagan depression, Erlian basin, northern China

Cited by 27 publications

References 19 publications

Syn‐sedimentary hydrothermal dolomites in a lacustrine rift basin: Petrographic and geochemical evidence from the lower Cretaceous Erlian Basin, Northern China

Syn‐sedimentary hydrothermal dolomites in a lacustrine rift basin: Petrographic and geochemical evidence from the lower Cretaceous Erlian Basin, Northern China

Relationship between source rock development and petroleum accumulation in the Erlian Basin, northern China

Geochemistry and origin of Ordovician oils in the Rewapu Block of the Halahatang Oilfield (NW China)

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