Geochemistry and source of crude oils in the Wensu uplift, Tarim Basin, NW China

Zhang, Jinhu; Yang, Youxing; Gao, Yongjin; Li, Sumei; Yu, Bingsong; Gong, Xinghong; Bai, Zhongkai; Miao, Miaoqing; Zhang, Yuanyin; Sun, Zhichao; Qi, Zhaolin

doi:10.1016/j.petrol.2021.109448

Cited by 6 publications

(6 citation statements)

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“…The isolated saturated hydrocarbon fraction is subsequently analyzed with an HP Agilent 6890/5975 GC-MS system. Detailed descriptions of this methodology and the specific instrument settings have been elaborated in prior publications. , …”

Section: Methodsmentioning

confidence: 99%

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Controls and Geological Significance of Macerals in Hybrid Shales: A Case Study on the Gaoyou Sag, Subei Basin, East China

Zhao,

Zeng,

et al. 2024

ACS Omega

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In the Gaoyou Sag located within the Subei Basin, the hybrid shales from the second member of the Funing Formation (E 1 f 2 ) have been identified as a prolific source of shale oil production, despite their characteristically low organic matter content (TOC < 1.5%). This observation suggests that specific macerals within these hybrid shales demonstrate a pronounced hydrocarbon generation potential, thus unveiling a new frontier for shale oil exploration endeavors. In this study, 16 samples were rigorously extracted from both mudstone and hybrid shale strata within the E 1 f 2 . An exhaustive suite of organic and inorganic geochemical analyses was conducted on these specimens. The analyses elucidated several key findings: (1) The maceral composition within the hybrid shales is predominantly comprised of alginite, solid bitumen, and inertinite. Remarkably, the variability of alginite content within the hybrid shales is more pronounced than that observed in high-TOC mudstones. High-TOC mudstones are characterized by a preponderance of lamalginite and a paucity of telalginite, leading to a diminished aggregate hydrocarbon potential. (2) Biomarker ratios (e.g., sterane/hopane, C 23 tricyclic terpane/αβ C 30 hopane, C 24 tetracyclic terpane/C 26 tricyclic terpane, etc.) suggest a primary derivation from lower aquatic organisms, with a secondary contribution from terrigenous organic matter within the hybrid shales. (3) The accretion of macerals is governed by an intricate set of factors, including the input of terrigenous detritus, paleosalinity, and paleoproductivity. (4) Alginite is identified as the principal constituent responsible for hydrocarbon genesis in hybrid shales. The proliferation of alginite facilitates the concurrent enrichment of shale oil and organic matter within the hybrid shales of the Subei Basin, illustrating a cooperative mechanism underlying the accumulation of shale oil and organic matter. This indicates that even hybrid shales with scant organic content exhibit considerable potential for shale oil exploration.

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Section: Methodsmentioning

confidence: 99%

“…Detailed descriptions of this methodology and the specific instrument settings have been elaborated in prior publications. 27,28 4. RESULTS…”

Section: Gas Chromatography−mass Spectrometry (Gc-ms)mentioning

confidence: 99%

Controls and Geological Significance of Macerals in Hybrid Shales: A Case Study on the Gaoyou Sag, Subei Basin, East China

Zhao,

Zeng,

et al. 2024

ACS Omega

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“…Based on whole-oil GC and total ion current chromatograms (TIC) of the saturated hydrocarbon fraction, the paraffin of the shale oils from the Songliao Basin essentially vanished, leaving a significant hump or unresolved complex mixture (Zhang et al, 2022). The GC-MS analysis of the rock extracts revealed the occurrence of n-alkanes (C13-C38 range) (Figure 6).…”

Section: Composition and Relative Distribution Of Hydrocarbons In The...mentioning

confidence: 99%

Hydrocarbon micro‐migration and differential enrichment mechanism of shale oil in upper Cretaceous Qingshankou Formation in Songliao Basin

Guan,

Meng,

Huang

et al. 2024

Geological Journal

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Shale reservoir has strong heterogeneity in mineral composition and oil content even at a short distance in the same interval. To better understand the accumulation mechanism of shale oil and hydrocarbon migration tendency in the interval, and explore the main influencing factors of distribution. This paper employed various methods, including thin‐section observation, TOC (total organic matter (OM)) analysis, rock pyrolysis, Soxhlet extraction, group component separation, and GC–MS (gas chromatography mass spectrometry) analysis of saturated hydrocarbons. The shale oil samples were collected from an exploratory well in the Songliao Basin, and the distribution and enrichment characteristics of shale oil interlayers were analysed. The results show that the first member of Qingshankou Formation (K2qn1) could be divided into six small layers. From Q1 to Q6, the lithofacies could be divided into three types: high‐frequency laminar shale, massive shale, and bioclastic shale. The lacustrine matrix shale of K2qn1 in Songliao Basin has medium TOC, and high oil contents, OM conversion rate. The TOC ranges from 1.5 to 4.2 wt%, S1 varies between 1.4 and 4 mg/g, S2 falls within the range of 4 to 10.6 mg/g, Tmax ranges from 351 to 497°C, and the OSI varies between 57 and 115.34 mg HC/g rock. The lower part of the K2qn1, Q1–Q4, characterized by high‐frequency laminar shale, contained residual shale oil, while the upper part of the K2qn1, Q5 and Q6, characterized by bioclastic shale and massive mudstone, and are dominated by in‐situ type shale oil. The crude oil in K2qn1 is homologous, and primarily undergoes micro‐migration. The Q5–Q6 section has the highest light oil content, while other regions with notable light components are located in the middle of Q1, the upper sections of Q2, Q3, and Q4.Q1–Q4 are primarily composed of residual shale oil, whereas Q5–Q6 is primarily composed of in‐situ shale oil, and the primary micro‐migration direction of shale oil occurs laterally within Q1–Q4. The lateral migration of each section mainly occurs at the upper part of Q3 and Q4, the lower part of Q1 and Q2, the bottom of Q5, and the interface between Q6 and the second member of Qingshankou formation (K2qn2). The block mudstone retains in‐situ shale oil, especially light hydrocarbons. Within the high‐frequency laminar shale, there is strong horizontal connectivity, and lateral hydrocarbon expulsion serves as the primary mechanism for micro‐migration in Q1–Q4. This paper can provide reference values for K2qn1 Formation shale oil and the migration and differential reservoir formation of medium and high‐maturity matrix shale oil.

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“…Zhang Shuhai et al (2021) concluded that the oil in Silurian asphaltic sands and Ordovician limestones was mixed-source from the Yuertusi and Saergan Formations [49]. Zhang Jinhu et al (2022) believed that the SN-1 and SN-2 (Shajingzi fault belt) Triassic oil migrated from the Awati Sag, characterized by high sulfur content, low wax content, lower Pr/Ph, and C 30 diahopanes/C 30 hopane ratios, high tricyclic terpenoids/pentacyclic terpenoid ratios, high C 29 hopane/C 30 hopane and sterane/hopane ratios, and a high content of dibenzothiophene in the three-fluorene series, indicating marine origin (from the Lower Paleozoic) [50].…”

Section: Hydrocarbon Accumulation Modes In the Awati Sag And Surround...mentioning

confidence: 99%

Geochemical Characteristics of the Paleozoic Marine Source Rocks and Ultra-Deep Hydrocarbon Accumulation Mode of the Awati Sag

Song,

Zhang,

Ding

et al. 2024

Energies

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The Lower Paleozoic of the Awati Sag and its periphery is a region with relatively low levels of exploration and stands as a frontier for ultra-deep hydrocarbon exploration. Based on outcrop and core samples, this study integrated organic geochemical analysis, total organic carbon (TOC) logging interpretation, and one-dimensional and two-dimensional hydrocarbon accumulation simulations, to clarify the primary source rock of the Lower Paleozoic and its characteristics, as well as its hydrocarbon accumulation mode. The findings indicate the following: (1) The Lower Paleozoic features two sets of industrial source rocks. The Yuertusi Formation, with its considerable thickness (approximately 200 m), widespread distribution, and elevated TOC (averaging approximately 5% from experimental data and logging interpretation), stands out as the Lower Paleozoic’s most pivotal source rock. (2) The Yuertusi and Saergan Formations are in a high-to-over-mature stage, with the Yuertusi initiating oil generation in the early Silurian and transitioning to gas by the late Permian. The Saergan began producing oil in the Carboniferous, followed by gas in the late Permian. (3) The potential ultra-deep gas reservoirs in the Awati Sag are mainly distributed in the structural traps closer to the deep faults in five potential target formations. Deep natural gas typically exhibits mixed-source signatures, with the mixing notably pronounced along the Shajingzi Fault Belt due to influential basin-controlling faults.

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Geochemistry and source of crude oils in the Wensu uplift, Tarim Basin, NW China

Cited by 6 publications

References 44 publications

Controls and Geological Significance of Macerals in Hybrid Shales: A Case Study on the Gaoyou Sag, Subei Basin, East China

Controls and Geological Significance of Macerals in Hybrid Shales: A Case Study on the Gaoyou Sag, Subei Basin, East China

Hydrocarbon micro‐migration and differential enrichment mechanism of shale oil in upper Cretaceous Qingshankou Formation in Songliao Basin

Geochemical Characteristics of the Paleozoic Marine Source Rocks and Ultra-Deep Hydrocarbon Accumulation Mode of the Awati Sag

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