Evidence of rift segmentation and controls of Middle to Late Jurassic synrift deposition in the Ryggsteinen ridge area, northern North Sea

AAPG Bulletin ◽  
2020 ◽  
Vol 104 (7) ◽  
pp. 1531-1565 ◽  
Author(s):  
Xiaoan Zhong ◽  
Alejandro Escalona
Keyword(s):  
North Sea ◽  
Late Jurassic ◽  
Ridge Area ◽  
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.

Controls on Late Jurassic, subtle sand distribution in the Tampen Spur area, Northern North Sea

1999 ◽  
Vol 5 (1) ◽  
pp. 827-838 ◽  
Author(s):  
N. H. DAWERS ◽  
A. M. BERGE ◽  
K.-O. HÄGER ◽  
C. PUIGDEFABREGAS ◽  
J. R. UNDERHILL
Keyword(s):  
North Sea ◽  
Late Jurassic ◽  
Northern North Sea

Late Jurassic Structural Inversion in the North Viking Graben and East Shetland Basin, UK North Sea

1992 ◽  
Vol 10 (4-5) ◽  
pp. 281-299 ◽  
Author(s):  
A. Booth ◽  
F.J. Stockley ◽  
J.A. Robbins
Keyword(s):  
North Sea ◽  
Seismic Data ◽  
Late Jurassic ◽  
The North ◽  
Anomalous Data ◽  
Structural Inversion ◽  
The North Sea ◽  
Northern North Sea ◽  
Well Data ◽  
The Impact

Interpretation of regional seismic data and analysis of available well data from the North Viking Graben suggest that a significant phase of structural inversion took place in the Late Jurassic and also in the early Cretaceous. It is believed that this inversion may be a consequence either of compression of the basin as a whole or alternatively, transpressional uplift along offset NW-SE fault systems. The north-south trending Penguin Ridge in UKCS quadrant 211 is interpreted as being such an inversion feature. The Penguin Ridge may well be an extreme example of apparent compression within the context of the Northern North Sea. However, it is clear that less well-developed structures of a similar type have previously been interpreted as simple extensional fault blocks. A compressional or transpressional mode of formation has implications for both reservoir diagenesis and faulting and thus important consequences for exploration play evaluation. It is also proposed that the Penguin Ridge is the northerly limit of a north-south trend or fairway in which compressional features can be observed from regional and field specific seismic data. Certainly there are many anomalous structures within the complex crestal areas of the majority of the Brent Province fields. The impact of such a model is the subject of continuing studies, but it is clear that as the search for more subtle plays intensifies in mature exploration areas such as the North Sea, it is important that the explorationist keeps an open mind, especially when confronted with apparently anomalous data.

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