Source Rocks and Oils of the Central and Northern North Sea

1984 ◽  
Author(s):  
B.S. Cooper ◽  
P.C. Barnard
Keyword(s):  
North Sea ◽  
Source Rocks ◽  
Northern North Sea

AN EARLY CRETACEOUS SOURCE ROCK IN THE KENDREW TERRACE, DAMPIER SUB-BASIN?

1996 ◽  
Vol 36 (1) ◽  
pp. 477 ◽  
Author(s):  
S. Ryan-Grigor ◽  
C. M. Griffiths
Keyword(s):  
Source Rock ◽  
North Sea ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Large Scale ◽  
Free Water ◽  
Organic Content ◽  
Source Rocks ◽  
The North ◽  
Northern North Sea

The Early to Middle Cretaceous is characterised worldwide by widespread distribution of dark shales with high gamma ray readings and high organic contents defined as dark coloured mudrocks having the sedimentary, palaeoecological and geochemical characteristics associated with deposition under oxygen-deficient or oxygen-free bottom waters. Factors that contributed to the formation of the Early to Middle Cretaceous 'hot shales' are: rising sea-level, a warm equable climate which promoted water stratification, and large scale palaeogeographic features that restrict free water mixing. In the northern North Sea, the main source rock is the Late Jurassic to Early Cretaceous Kimmeridge Clay/Draupne Formation 'hot shale' which occurs within the Viking Graben, a large fault-bounded graben, in a marine environment with restricted bottom circulation and often anaerobic conditions. Opening of the basin during a major trans-gressive event resulted in flushing, and deposition of normal open marine shales above the 'hot shales'. The Late Callovian to Berriasian sediments in the Dampier Sub-basin are considered to have been deposited in restricted marine conditions below a stratified water column, in a deep narrow bay. Late Jurassic to Early Cretaceous marine sequences that have been cored on the North West Shelf are generally of moderate quality, compared to the high quality source rocks of the northern North Sea, but it should be noted that the cores are from wells on structural highs. The 'hot shales' are not very organic-rich in the northern Dampier Sub-basin and are not yet within the oil window, however seismic data show a possible reduction in velocity to the southwest in the Kendrew Terrace, suggesting that further south in the basin the shales may be within the oil window and may also be richer in organic content. In this case, they may be productive source rocks, analogous to the main source rock of the North Sea.

Oil migration makes the difference: regional distribution of carbonate cement δ13C in northern North Sea Tertiary sandstones

Clay Minerals ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 69-76 ◽  
Author(s):  
C. I. Macaulay ◽  
A. E. Fallick ◽  
R. S. Haszeldine ◽  
G. E. McAulay
Keyword(s):  
North Sea ◽  
Regional Distribution ◽  
Distribution Patterns ◽  
Source Rocks ◽  
Oil Migration ◽  
Bacterial Fermentation ◽  
Carbonate Cement ◽  
Carbonate Cements ◽  
Reservoir Sandstones ◽  
Northern North Sea

AbstractCarbonate cements in Tertiary reservoir sandstones from the northern North Sea have distinctive carbon isotopic compositions (δ13C). Oil migration up faults from deeper structures and biodegradation of oil pools are factors of particular importance in influencing the δ13C of carbonate cements in these sandstones. As a result, δ13C can be used as an exploration guide to locating the positions of vertical leakoff points from the Jurassic source rocks. The histogram distribution of δ13C in these carbonate cements is trimodal, with peaks at around −26, −3 and +12‰ (ranges −22 to −30, +2 to −10 and +8 to +18‰, respectively). Bacterial processes played major roles in determining this distribution, with oxidative biodegradation of oil resulting in carbonate cements with very negative compositions and bacterial fermentation resulting in the positive δ13C cements. δ13C distribution patterns may be used to differentiate Tertiary reservoir sandstones from Jurassic in the northern North Sea, and these regional carbonate cement δ13C datasets allow geologically useful inferences to be drawn from δ13C data from new sample locations.

scholarly journals Source rocks

1982 ◽  
Vol 8 ◽  
pp. 73-86
Author(s):  
Holger Lindgreen ◽  
Erik Thomsen ◽  
Per Wrang
Keyword(s):  
Source Rock ◽  
North Sea ◽  
Oil Fields ◽  
Source Rocks ◽  
Published Data ◽  
The North ◽  
East Midlands ◽  
The North Sea ◽  
Northern North Sea ◽  
Coal Measures

Little has been published on source rocks of Paleozoic and Mesozoic ages in the North Sea. Gas in many fields of the southern North Sea is known to originate from Late Carboniferous Coal Measures, (Eames 1975). In the East Midlands area of England, the oil in Carboniferous reservoirs is believed to originate from Carboniferous rocks (Bernard & Cooper 1981). Several papers published on the oil fields in the southern and northern North Sea suggest a Late Jurassic source rock (see review by Weismann 1979 and Bernard & Cooper 1981). Also Early and Middle Jurassic shales are suggested as possible source rocks in parts of the North Sea (Fuller 1975, Oudin 1976). Published data on source rock conditions in the Danish sector is limited to Weismann (1979).

Hydrocarbon plays in the northern North Sea

1990 ◽  
Vol 50 (1) ◽  
pp. 441-470 ◽  
Author(s):  
R. M. Pegrum ◽  
A. M. Spencer
Keyword(s):  
North Sea ◽  
Northern North Sea
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