Sequence stratigraphy, palaeogeography, and coal accumulation of the fluvio-lacustrine Middle Jurassic Xishanyao Formation in central segment of southern Junggar Basin, NW China

2018 ◽  
Vol 192 ◽  
pp. 14-38 ◽  
Author(s):  
Ya-nan Li ◽  
Longyi Shao ◽  
Haihai Hou ◽  
Yue Tang ◽  
Yuan Yuan ◽  
...  
Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-23 ◽  
Author(s):  
Binfeng Cao ◽  
Xiaorong Luo ◽  
Likuan Zhang ◽  
Fenggui Sui ◽  
Huixi Lin ◽  
...  

The Middle Jurassic Toutunhe Formation at depths of approximately 4000–6000 m has increasingly come into focus as a current deep reservoir target in the central Junggar Basin (NW China). Based on petrography, SEM, stable isotopes, and fluid inclusion analyses, the goals of this study were to investigate the effect of depositional lithofacies on sandstone diagenetic heterogeneity and to examine the relationship between diagenetic evolution and oil charge within a heterogeneous reservoir. Grain size controls the overall abundance of cement and porosity and reservoir properties through its effect on ductile lithic sand grains and hence on mechanical compaction. Early diagenetic calcite cement is an exception to this trend. Ductile lithic-rich, very fine-grained sandstones featured compaction of easily deformed, clay-rich grains, resulting in a very rapid loss of porosity during burial. In contrast, dissolution and cementation occurred as well as ductile compaction in the fine-grained sandstones. Two episodes of oil charge occurred in the relatively coarser-grained sandstone lithofacies. Diagenesis progressed alternately with oil emplacement, and some diagenetic alterations and oil charge occurred simultaneously. Ductile lithic-rich, highly compacted sandstones and tightly calcite-cemented sandstones can create permeability barriers embedded in permeable reservoir sandstones, probably resulting in heterogeneous flow.


2004 ◽  
Vol 91 (12) ◽  
pp. 589-593 ◽  
Author(s):  
Michael W. Maisch ◽  
Andreas T. Matzke ◽  
Ge Sun

PalZ ◽  
2003 ◽  
Vol 77 (2) ◽  
pp. 281-292 ◽  
Author(s):  
Michael W. Maisch ◽  
Andreas T. Matzke

Author(s):  
Lars Stemmerik ◽  
Gregers Dam ◽  
Nanna Noe-Nygaard ◽  
Stefan Piasecki ◽  
Finn Surlyk

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stemmerik, L., Dam, G., Noe-Nygaard, N., Piasecki, S., & Surlyk, F. (1998). Sequence stratigraphy of source and reservoir rocks in the Upper Permian and Jurassic of Jameson Land, East Greenland. Geology of Greenland Survey Bulletin, 180, 43-54. https://doi.org/10.34194/ggub.v180.5085 _______________ Approximately half of the hydrocarbons discovered in the North Atlantic petroleum provinces are found in sandstones of latest Triassic – Jurassic age with the Middle Jurassic Brent Group, and its correlatives, being the economically most important reservoir unit accounting for approximately 25% of the reserves. Hydrocarbons in these reservoirs are generated mainly from the Upper Jurassic Kimmeridge Clay and its correlatives with additional contributions from Middle Jurassic coal, Lower Jurassic marine shales and Devonian lacustrine shales. Equivalents to these deeply buried rocks crop out in the well-exposed sedimentary basins of East Greenland where more detailed studies are possible and these basins are frequently used for analogue studies (Fig. 1). Investigations in East Greenland have documented four major organic-rich shale units which are potential source rocks for hydrocarbons. They include marine shales of the Upper Permian Ravnefjeld Formation (Fig. 2), the Middle Jurassic Sortehat Formation and the Upper Jurassic Hareelv Formation (Fig. 4) and lacustrine shales of the uppermost Triassic – lowermost Jurassic Kap Stewart Group (Fig. 3; Surlyk et al. 1986b; Dam & Christiansen 1990; Christiansen et al. 1992, 1993; Dam et al. 1995; Krabbe 1996). Potential reservoir units include Upper Permian shallow marine platform and build-up carbonates of the Wegener Halvø Formation, lacustrine sandstones of the Rhaetian–Sinemurian Kap Stewart Group and marine sandstones of the Pliensbachian–Aalenian Neill Klinter Group, the Upper Bajocian – Callovian Pelion Formation and Upper Oxfordian – Kimmeridgian Hareelv Formation (Figs 2–4; Christiansen et al. 1992). The Jurassic sandstones of Jameson Land are well known as excellent analogues for hydrocarbon reservoirs in the northern North Sea and offshore mid-Norway. The best documented examples are the turbidite sands of the Hareelv Formation as an analogue for the Magnus oil field and the many Paleogene oil and gas fields, the shallow marine Pelion Formation as an analogue for the Brent Group in the Viking Graben and correlative Garn Group of the Norwegian Shelf, the Neill Klinter Group as an analogue for the Tilje, Ror, Ile and Not Formations and the Kap Stewart Group for the Åre Formation (Surlyk 1987, 1991; Dam & Surlyk 1995; Dam et al. 1995; Surlyk & Noe-Nygaard 1995; Engkilde & Surlyk in press). The presence of pre-Late Jurassic source rocks in Jameson Land suggests the presence of correlative source rocks offshore mid-Norway where the Upper Jurassic source rocks are not sufficiently deeply buried to generate hydrocarbons. The Upper Permian Ravnefjeld Formation in particular provides a useful source rock analogue both there and in more distant areas such as the Barents Sea. The present paper is a summary of a research project supported by the Danish Ministry of Environment and Energy (Piasecki et al. 1994). The aim of the project is to improve our understanding of the distribution of source and reservoir rocks by the application of sequence stratigraphy to the basin analysis. We have focused on the Upper Permian and uppermost Triassic– Jurassic successions where the presence of source and reservoir rocks are well documented from previous studies. Field work during the summer of 1993 included biostratigraphic, sedimentological and sequence stratigraphic studies of selected time slices and was supplemented by drilling of 11 shallow cores (Piasecki et al. 1994). The results so far arising from this work are collected in Piasecki et al. (1997), and the present summary highlights the petroleum-related implications.


2021 ◽  
Vol 124 ◽  
pp. 104808 ◽  
Author(s):  
Felix J. Augustin ◽  
Andreas T. Matzke ◽  
Michael W. Maisch ◽  
Hans-Ulrich Pfretzschner

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