New insights about petroleum geology and exploration of Qiangtang Basin, northern Tibet, China: A model for low-degree exploration

Fu, Xiugen; Wang, Jian; Tan, Fang; Chen, Ming; Li, Zhongxiong; Zeng, Yuhong; Feng, Xinglei

doi:10.1016/j.marpetgeo.2016.06.015

Cited by 34 publications

(29 citation statements)

References 20 publications

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“…The Tibetan Plateau is composed from north to south of the Songpan-Ganzi flysch complex, the Qiangtang Yin and Harrison, 2000;Fu et al, 2016bFu et al, , 2020Zeng et al, 2015). The Mesozoic Qiangtang Basin is situated in the central Tibetan Plateau and is bounded by the Hoh Xil -Jinsha River suture to the north and the Bangong Lake -Nujiang River suture to the south ( Fig.…”

Section: Geological Settingmentioning

confidence: 99%

“…During Triassic to Late Jurassic time, most of the basin was fully marine with widespread deposition of carbonates and interbedded clastics, forming a sedimentary package several kilometres thick (Zhao et al, 2000). Upper Triassic siliciclastics, mostly confined to the margins of the Qiangtang Basin (Fu et al, 2016b), are referred to as the Tumengela, Bagong and Zangxiahe Formations (Fig. 2).…”

Section: Geological Settingmentioning

confidence: 99%

“…The north Tibet region is part of the eastern Tethyan domain which is known to be rich in hydrocarbon reserves (Klemme and Ulmishek, 1991). Triassic and Jurassic source rocks occur widely in this area (Zhao et al, 2000;Wang et al, 2010;Fu et al, 2016b). However, relatively little work has been done on the hydrocarbon resource potential of the basin (Wang et al, 2009;Yang et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Upper Triassic organic-rich mudstones and shales have attracted increasing attention as potential source China rocks in the Qiangtang Basin (Ding et al, 2011;Zeng et al, 2013;Fu et al, 2016b) and occur at outcrop at the margins of the Northern Qiangtang Depression and in the central uplift (Fig. 1b).…”

Section: Introductionmentioning

confidence: 99%

“…2) . The Tumengela Formation occurs mainly along the margin of the basin and consists of shales, mudstones, sandstones and marls with intercalated coals, representing deposition in a coastal swamp environment (Fu et al, 2016b). The Zangxiahe Formation in the northern part of the basin consists of shallow-marine shales and sandstones (Zeng et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Organic‐rich Shales in the Upper Triassic Zangxiahe Formation, Northern Qiangtang Depression, Northern Tibet: Depositional Environment and Hydrocarbon Generation Potential

Zeng

Wang

Chen

et al. 2020

Journal of Petroleum Geology

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This study reports on the organic geochemical characteristics of high‐TOC shales in the Upper Triassic Zangxiahe Formation from a study area in the north of the Northern Qiangtang Depression, northern Tibet. A total of fifty outcrop samples from the Duoseliangzi, Zangxiahe South and Zangxiahe East locations were studied to evaluate the organic matter content of the shales and their thermal maturity and depositional environment, and to assess their hydrocarbon generation potential. Zangxiahe Formation shales from the Duoseliangzi profile have moderate to good source rock potential with TOC contents of up to 3.4 wt.% (average 1.2 wt.%) and potential yield (S1+S2) of up to 1.11 mg HC/g rock. Vitrinite reflectance (Ro) and Tmax values show that the organic matter is highly mature, corresponding to the condensate/wet gas generation stage. The shales contain mostly Types II and I kerogen mixed with minor Type III, and have relatively high S/C ratios, high contents of amorphous sapropelinite, low Pr/Ph ratios, high values of the C35 homohopane index (up to 3.58%), abundant gammacerane content, and a predominance of C27 steranes. These parameters indicate a saline, shallow‐marine depositional setting with an anoxic, stratified water column. The source of organic matter was mainly aquatic OM (algal/bacterial) with subordinate terrigenous OM. Zangxiahe Formation shale samples from the Zangxiahe East and Zangxiahe South locations have relatively low TOC contents (0.2 to 0.8 wt.%) with Type II kerogen, suggesting poor to medium hydrocarbon generation potential. Ro and Tmax values indicate that organic matter from these locations is overmature. The discovery of organic‐rich Upper Triassic shales with source rock potential in the north of the Northern Qiangtang Depression will be of significance for oil and gas exploration elsewhere in the Qiangtang Basin. Future exploration should focus on locations such as Bandaohu to the SE of the study area where the organic‐rich shales are well developed, and where structural traps have been recorded together with potential reservoir rocks and thick mudstones which could act as seals.

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Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Organic‐rich Shales in the Upper Triassic Zangxiahe Formation, Northern Qiangtang Depression, Northern Tibet: Depositional Environment and Hydrocarbon Generation Potential

Zeng

Wang

Chen

et al. 2020

Journal of Petroleum Geology

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Geochemical characteristics of Early Cretaceous marine oil shale from the Changshe Mountain area in the northern Qiangtang Basin, Tibet: Implications for palaeoweathering, provenance, tectonic setting, and organic matter accumulation

et al. 2019

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The Early Cretaceous Shengli River–Changshe Mountain marine oil shale belt, located in the northern Qiangtang Basin, Tibet, is estimated to be the largest marine oil shale resource in China. However, its palaeoweathering, provenance, and tectonic setting during the depositional history have received little interest. In this paper, 19 outcrop marine oil shale samples from the ChangsheMountain (CSM) area were studied to investigate the provenance, palaeoclimate, palaeoweathering, and tectonic setting during the marine oil shale deposition. The total organic carbon and organic sulphur contents of the CSM oil shales range from 2.2% to 13.44% and 0.19% to 1.08%, respectively. The CSM oil shale samples contain abundant carbonate (e.g., calcite and dolomite), quartz, and clay minerals. The clay minerals of the CSM oil shale samples is dominated by illite and then by smectite. Other minerals, including haematite, apatite, pyrite, baryte, and celestite, were also identified by scanning electron microscope–energy‐dispersive X‐ray spectrometer. The total rare earth element (∑REE) contents of the oil shales range from 9.01 to 105.96 ppm (average 57.56 ppm), close to the average REE contents of U.S. coals. The REE contents in oil shale samples are mainly controlled by terrigenous input. The CSM oil shales show LREE‐enriched, HREE‐depleted, with the LREE/HREE ratios ranging from 5.12 to 10.18, negative Eu anomalies (0.56–0.84) and slightly negative Ce anomalies (0.87–1.05). The chemical index of alteration values of the CSM oil shales range from 67 to 76 (average 73), indicating a moderate chemical weathering condition. Sr/Cu and Rb/Sr ratios suggest the CSM oil shales were mainly deposited under a warm and humid climate regime. Sr/Ba ratios, ranging from 0.54 to 7.84, suggest a palaeoenvironment with fluctuant salinity. Major element, trace element, and REE relationships indicate that the CSM oil shales are mainly from the felsic and intermediate igneous rocks. The REE distribution patterns of the CSM oil shales are similar to the Late Triassic Nadi Kangri felsic volcanic rocks in the Qiangtang Basin, indicating that the CSM oil shale may be derived from the Late Triassic volcanic rocks and the oil shales were mainly formed in rift tectonic setting. Favourable preservation condition (e.g., warmer palaeoclimate, higher palaeosalinity, and dysoxic to anoxic water column environment) could be the main controlling factor for organic matter accumulation.

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Demise of the Middle Jurassic carbonate platform: Responses to sea‐level fall in the Qiangtang Basin, Eastern Tethys

Gao

et al. 2020

Geological Journal

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Many studies have been focused on the development of carbonate platforms, however, the controlling factors of their evolution are still unclear. The QTKT1 well, drilled in 2016 by the Chengdu Center of the China Geological Survey at the Northern Qiangtang Depression, has allowed further studies of Jurassic environments and resources in the Eastern Tethys. In this study, we investigate variations in spectral gamma‐ray logs and CaCO3 content and perform a cyclostratigraphic analysis in the Xiali mudstones and Buqu limestones and Xiali mudstone to analyse causes for the demise of the Middle Jurassic carbonate platform in the Qiangtang Basin. The concentrations of Th, K, U, and Th/U and Th/K ratios increase suddenly from the Buqu Formation to the Xiali Formation, suggesting increased terrigenous input and/or decreased carbonate production rates. Cyclostratigraphic analysis detects the existence of astronomical cycles and an abrupt change in sediment accumulation rates within the target intervals. Combined with sedimentary facies analysis, our research suggests that the demise of the Middle Jurassic carbonate platform may have been caused by terrigenous detrital inputs into the Qiangtang Basin. High‐frequency sea‐level fluctuations increased terrestrial inputs and carbonate production rates at the orbital scale. The regression happened before the facies change and controlled terrestrial inputs at a larger scale, which resulted in the demise of the carbonate platforms. Contrary to the Western Tethys, a regression took place from the Bathonian to Callovian ages in the Qiangtang Basin, Eastern Tethys, which increased the exposure levels. The large exposure led to significant erosion, accelerated detrital input from the land to the Northern Qiangtang Depression, reduced carbonate production as well as resulted in the demise of the Buqu carbonate platform. The relative sea‐level fall is mainly the result of the regional tectonism during this period.

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New insights about petroleum geology and exploration of Qiangtang Basin, northern Tibet, China: A model for low-degree exploration

Cited by 34 publications

References 20 publications

Organic‐rich Shales in the Upper Triassic Zangxiahe Formation, Northern Qiangtang Depression, Northern Tibet: Depositional Environment and Hydrocarbon Generation Potential

Organic‐rich Shales in the Upper Triassic Zangxiahe Formation, Northern Qiangtang Depression, Northern Tibet: Depositional Environment and Hydrocarbon Generation Potential

Geochemical characteristics of Early Cretaceous marine oil shale from the Changshe Mountain area in the northern Qiangtang Basin, Tibet: Implications for palaeoweathering, provenance, tectonic setting, and organic matter accumulation

Demise of the Middle Jurassic carbonate platform: Responses to sea‐level fall in the Qiangtang Basin, Eastern Tethys

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