The Carrack Field, Blocks 49/14b, 49/15a and 49/15b, UK North Sea

AbstractThe Carrack Field, located in the Southern North Sea Blocks 49/14b and 49/15a, has of the order or 15 bcm (530 bcf) gas initially in place and is operated by Shell UK Ltd. The field consists of a pop-up structure in the south of the field and extends to the north with a gently-dipping monoclinal structure. The reservoir comprises sandstones of the Permian Silverpit and Leman Sandstone formations, which contain c. 85% of the in-place resources. The quality of the reservoir decreases rapidly to the north. Gas is also produced from Carboniferous sandstones of late Duckmantian (Westphalian B)–Bolsovian (Westphalian C) age.Initially, the field was in pressure communication both laterally and vertically with a single gas–water contact. During production time, however, the three main fault blocks behaved independently, and decimetre-thick shale intervals acted as vertical baffles between the sandstone units.The Carrack Field has been in production since 2003 and is developed by a single platform with seven mainly deviated wells. The current production rate is c. 0.7 MMm3/day (25 MMscfgd). Until the end of field life in the 2030s, the field is expected to produce gas of the order of a few bcm. The main remaining opportunity is the undeveloped Carrack West compartment.

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Strategy for Protecting the North Sea: A Chemical Industry Perspective

Water Science & Technology ◽

10.2166/wst.1991.0300 ◽

1991 ◽

Vol 24 (10) ◽

pp. 269-276

Author(s):

J. R. Lawrence ◽

N. C. D. Craig

Keyword(s):

North Sea ◽

Chemical Industry ◽

Important Research ◽

The Public ◽

The North ◽

Anthropogenic Inputs ◽

Seven Principles ◽

The North Sea ◽

The Cost

The public has ever-rising expectations for the environmental quality of the North Sea and hence of everreducing anthropogenic inputs; by implication society must be willing to accept the cost of reduced contamination. The chemical industry accepts that it has an important part to play in meeting these expectations, but it is essential that proper scientific consideration is given to the potential transfer of contamination from one medium to another before changes are made. A strategy for North Sea protection is put forward as a set of seven principles that must govern the management decisions that are made. Some areas of uncertainty are identified as important research targets. It is concluded that although there have been many improvements over the last two decades, there is more to be done. A systematic and less emotive approach is required to continue the improvement process.

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The Size of Diatoms II. Further Observations on Rhizosolenia styliformis (Brightwell)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400012121 ◽

1946 ◽

Vol 26 (3) ◽

pp. 271-284 ◽

Cited By ~ 15

Author(s):

R. S. Wimpenny

Keyword(s):

North Sea ◽

Indicator Species ◽

Separate Species ◽

Southern North Sea ◽

Auxospore Formation ◽

The North ◽

The North Sea ◽

Set Up ◽

The Antarctic

1. Diameter measurements of Rhizosolenia styliformis from the Antarctic, the subtropical Atlantic and Pacific Oceans and from the North Sea and neighbouring waters have made it appear necessary to set up two varieties, oceanica and semispina, in addition to the type of the species R. styliformis. The type as I describe it has been called var. longispina by Hustedt, but elsewhere it has often been figured as the var. oceanica of this paper. Var. semispina is synonymous with the form represented by Karsten as R. semispina Hensen. It differs from R. semispina as drawn by Hensen and its synonym R. hebetata forma semispina Gran, but is thought likely to be linked by intermediates. If this is so R. hebetata may have to be extended to include and suppress R. styliformis, as var. semispina is linked to the type by intermediates. Var. oceanica has no intermediate forms and, if R. hebetata is to be extended, this variety should be established as a separate species.2. Var. oceanica is absent from the southern North Sea and appears to be an indicator species related to oceanic inflow.3. Auxospore formation was observed for the type in the southern North Sea in 1935 and biometric observations suggest that a period of 3-4 years elapsed between the production of auxospore generations in that area. Outside the southern North Sea for the type, measurements give no indication of auxospore generations occurring at intervals exceeding a year. While auxospore formation has been seen in var. oceanica from the Shetlands area samples of June 1935 and July 1938, this phenomenon has not been observed for var. semispina.

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The impact of sedimentary alkalinity release on the water column CO<sub>2</sub> system in the North Sea

Biogeosciences ◽

10.5194/bg-13-841-2016 ◽

2016 ◽

Vol 13 (3) ◽

pp. 841-863 ◽

Cited By ~ 19

Author(s):

H. Brenner ◽

U. Braeckman ◽

M. Le Guitton ◽

F. J. R. Meysman

Keyword(s):

Coastal Zone ◽

North Sea ◽

Dissolved Inorganic Carbon ◽

Co2 Uptake ◽

Overlying Water ◽

Southern North Sea ◽

The North ◽

Alkalinity Generation ◽

The North Sea ◽

The Impact

Abstract. It has been previously proposed that alkalinity release from sediments can play an important role in the carbonate dynamics on continental shelves, lowering the pCO2 of seawater and hence increasing the CO2 uptake from the atmosphere. To test this hypothesis, sedimentary alkalinity generation was quantified within cohesive and permeable sediments across the North Sea during two cruises in September 2011 (basin-wide) and June 2012 (Dutch coastal zone). Benthic fluxes of oxygen (O2), alkalinity (AT) and dissolved inorganic carbon (DIC) were determined using shipboard closed sediment incubations. Our results show that sediments can form an important source of alkalinity for the overlying water, particularly in the shallow southern North Sea, where high AT and DIC fluxes were recorded in near-shore sediments of the Belgian, Dutch and German coastal zone. In contrast, fluxes of AT and DIC are substantially lower in the deeper, seasonally stratified, northern part of the North Sea. Based on the data collected, we performed a model analysis to constrain the main pathways of alkalinity generation in the sediment, and to quantify how sedimentary alkalinity drives atmospheric CO2 uptake in the southern North Sea. Overall, our results show that sedimentary alkalinity generation should be regarded as a key component in the CO2 dynamics of shallow coastal systems.

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Depositional facies, diagenetic clay minerals and reservoir quality of Rotliegend sediments in the Southern Permian Basin (North Sea): a review

Clay Minerals ◽

10.1180/claymin.1982.017.1.06 ◽

1982 ◽

Vol 17 (1) ◽

pp. 55-67 ◽

Cited By ~ 32

Author(s):

U. Seemann

Keyword(s):

Clay Minerals ◽

North Sea ◽

Effective Porosity ◽

Hydrocarbon Exploration ◽

Reservoir Quality ◽

Burial Diagenesis ◽

Permian Basin ◽

Northern Margin ◽

The North

AbstractThe Southern Permian Basin of the North Sea represents an elongate E-W oriented depo-centre along the northern margin of the Variscan Mountains. During Rotliegend times, three roughly parallel facies belts of a Permian desert developed, these following the outline of the Variscan Mountains. These belts were, from south to north, the wadi facies, the dune and interdune facies, and the sabkha and desert lake facies. The bulk of the gas reservoirs of the Rotliegend occur in the aeolian dune sands. Their recognition, and the study of their geometry, is therefore important in hydrocarbon exploration. Equally important is the understanding of diagenesis, particularly of the diageneticaily-formed clay minerals, because they have an important influence on the reservoir quality of these sands. Clay minerals were introduced to the aeolian sands during or shortly after their deposition in the form of air-borne dust, which later formed thin clay films around the grains. During burial diagenesis, these clay films may have acted as crystallization nuclei for new clay minerals or for the transformation of existing ones. Depending on their crystallographic habit, the clay minerals can seriously affect the effective porosity and permeability of the sands.

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A southern North Sea Miocene dinoflagellate cyst zonation

Netherlands Journal of Geosciences – Geologie en Mijnbouw ◽

10.1017/s0016774600020369 ◽

2004 ◽

Vol 83 (4) ◽

pp. 267-285 ◽

Cited By ~ 36

Author(s):

D.K. Munsterman ◽

H. Brinkhuis

Keyword(s):

The Netherlands ◽

North Sea ◽

North Atlantic ◽

The South ◽

Dinoflagellate Cyst ◽

South Eastern ◽

Southern North Sea ◽

Age Model

AbstractAn integrated stratigraphical analysis emphasizing organic-walled dinoflagellate cyst (dinocyst) distribution has been carried out on multiple boreholes penetrating the Miocene in the subsurface of the Netherlands (southern North Sea Basin). The bulk of the investigated successions is attributed to the Breda Formation, a regional lithostatigraphical unit most complete in the south-eastern part of the Netherlands. In concert with a first regional integrated bio (chrono) sequence-stratigraphical framework, fourteen informal dinocyst zones for the southern North Sea Miocene (SNSM), and three subzones are proposed for the Breda Formation. By also integrating (chrono)stratigraphic information from Mediterranean and North Atlantic dinocyst studies a first ever detailed age-model is here proposed for the Miocene in the subsurface of the Netherlands.

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Marine Growth on North Sea Fixed Steel Platforms: Insights From the Decommissioning Industry

Volume 1A: Offshore Technology ◽

10.1115/omae2014-23352 ◽

2014 ◽

Author(s):

Chadi Mallat ◽

Alistair Corbett ◽

Glyn Harris ◽

Marc Lefranc

Keyword(s):

North Sea ◽

Gas Industry ◽

Southern North Sea ◽

The North ◽

The North Sea ◽

Insight Into

It is reputed in the Oil & Gas industry that marine growth is overestimated in the North Sea. Can we quantify this overestimation to better tackle the challenges marine growth incurs? This paper provides insight into the intrinsic and diverse nature of marine growth. It documents the biofouling development and the factors that affect it globally. Focus is made on fixed steel platforms in the North Sea approaching the end of their economic lives. A methodology to quantify the weight of marine growth is proposed and illustrated. 28 years after its installation, the weight of marine growth accumulated on Valhall 2/4G jacket located in Southern North Sea is evaluated based on the proposed method. It is confirmed that the current regulations overestimate the weight of marine growth in the North Sea.

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Investigations Upon the Water Movements in the English Channel. Summer, 1924

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400058410 ◽

1927 ◽

Vol 14 (3) ◽

pp. 685-721 ◽

Cited By ~ 9

Author(s):

J. N. Carruthers

Keyword(s):

North Sea ◽

English Channel ◽

Average Speed ◽

Southern North Sea ◽

The North ◽

Westerly Winds ◽

The North Sea

In July, 1924, 250 floating, and an equal number of bottom-trailing, bottles were put out at selected places in the western English Channel. Fifty of each type were put out at each of the two routine Stations E2 and E3, and the same number was “liberated” at each of three selected stretches along the steamship route from Southampton to St. Malo. Those surface bottles, which did not strand locally, travelled rapidly up Channel towards the North Sea and across it. Many bottles arrived in the Skager-Rack after performing their journey of some 700 miles at the rate of 6 miles a day and more. An adequate study of wind conditions, as recorded at several stations along the length of the Channel and at one station in the southern North Sea, revealed the fact that there was, for some 5½ months (counting from the time of liberation of the bottles), an almost uninterrupted predominance of south-westerly winds—as recorded at all stations considered. The whole area of the Channel was swept by south-westerly winds of average speed of some 9 miles a day for at least 5½ months subsequent to the time of putting out of the bottles. July, 1924, had (according to the Falmouth Observatory records) the largest proportion of westerly winds experienced for 54 years; 20 days of this month had winds with westerly components. The association of the unusually persistent westerly winds with the rapid travel of surface bottles towards and across the North Sea is interesting.

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Warm-water decapods and the trophic amplification of climate in the North Sea

Biology Letters ◽

10.1098/rsbl.2010.0394 ◽

2010 ◽

Vol 6 (6) ◽

pp. 773-776 ◽

Cited By ~ 15

Author(s):

J. A. Lindley ◽

G. Beaugrand ◽

C. Luczak ◽

J.-M. Dewarumez ◽

R. R. Kirby

Keyword(s):

North Sea ◽

Warm Water ◽

Climate Signal ◽

Southern North Sea ◽

The North ◽

Ecosystem Shift ◽

The North Sea ◽

Induced Changes ◽

Water Species

A long-term time series of plankton and benthic records in the North Sea indicates an increase in decapods and a decline in their prey species that include bivalves and flatfish recruits. Here, we show that in the southern North Sea the proportion of decapods to bivalves doubled following a temperature-driven, abrupt ecosystem shift during the 1980s. Analysis of decapod larvae in the plankton reveals a greater presence and spatial extent of warm-water species where the increase in decapods is greatest. These changes paralleled the arrival of new species such as the warm-water swimming crab Polybius henslowii now found in the southern North Sea. We suggest that climate-induced changes among North Sea decapods have played an important role in the trophic amplification of a climate signal and in the development of the new North Sea dynamic regime.

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