The impact of a quick 4D seismic survey and processing over the Halfdan Field, Danish North Sea

First Break ◽  
2014 ◽  
Vol 32 (2017) ◽  
Author(s):  
M.A. Calvert ◽  
H.H. Roende ◽  
I.H. Herbert ◽  
J. Za ◽  
P. Hickman ◽  
...  
Keyword(s):  
North Sea ◽  
Seismic Survey ◽  
4D Seismic ◽  
The Impact

Time-Lapse Seismic for Reservoir Management: Case Studies From Offshore Niger Delta, Nigeria

2016 ◽  
Vol 19 (03) ◽  
pp. 391-402
Author(s):  
Sunday Amoyedo ◽  
Emmanuel Ekut ◽  
Rasaki Salami ◽  
Liliana Goncalves-Ferreira ◽  
Pascal Desegaulx
Keyword(s):  
Case Studies ◽  
Niger Delta ◽  
Reservoir Management ◽  
Time Lapse ◽  
Seismic Survey ◽  
Elastic Model ◽  
Field Development ◽  
4D Seismic ◽  
The Impact

Summary This paper presents case studies focused on the interpretation and integration of seismic reservoir monitoring from several fields in conventional offshore and deepwater Niger Delta. The fields are characterized by different geological settings and development-maturity stages. We show different applications varying from qualitative to quantitative use of time-lapse (4D) seismic information. In the first case study, which is in shallow water, the field has specific reservoir-development challenges, simple geology, and is in phased development. On this field, 4D seismic, which was acquired several years ago, is characterized by poor seismic repeatability. Nevertheless, we show that because of improvements from seismic reprocessing, 4D seismic makes qualitative contributions to the ongoing field development. In the second case study, the field is characterized by complex geological settings. The 4D seismic is affected by overburden with strong lateral variations in velocity and steeply dipping structure (up to 40°). Prestack-depth-imaging (PSDM) 4D seismic is used in a more-qualitative manner to monitor gas injection, validate the geologic/reservoir models, optimize infill injector placement, and consequently, enhance field-development economics. The third case study presents a deep offshore field characterized by a complex depositional system for some reservoirs. In this example, good 4D-seismic repeatability (sum of source- and receiver-placement differences between surveys, dS+dR) is achieved, leading to an increased quantitative use of 4D monitoring for the assessment of sand/sand communication, mapping of oil/water (OWC) front, pressure evolution, and dynamic calibration of petro-elastic model (PEM), and also as a seismic-based production-logging tool. In addition, 4D seismic is used to update seismic interpretation, provide a better understanding of internal architecture of the reservoirs units, and, thereby, yield a more-robust reservoir model. The 4D seismic in this field is a key tool for field-development optimization and reservoir management. The last case study illustrates the need for seismic-feasibility studies to detect 4D responses related to production. In addition to assessing the impact of the field environment on the 4D- seismic signal, these studies also help in choosing the optimum seismic-survey type, design, and acquisition parameters. These studies would possibly lead to the adoption of new technologies such as broad-band streamer or nodes acquisition in the near future.

scholarly journals Multi-Proxy Characterisation of the Storegga Tsunami and Its Impact on the Early Holocene Landscapes of the Southern North Sea

Geosciences ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 270 ◽  
Author(s):  
Vincent Gaffney ◽  
Simon Fitch ◽  
Martin Bates ◽  
Roselyn L. Ware ◽  
Tim Kinnaird ◽  
...  
Keyword(s):  
North Sea ◽  
River System ◽  
Seismic Survey ◽  
Tsunami Deposit ◽  
Southern North Sea ◽  
The North ◽  
Sediment Deposits ◽  
The North Sea ◽  
Northern North Sea ◽  
The Impact

Doggerland was a landmass occupying an area currently covered by the North Sea until marine inundation took place during the mid-Holocene, ultimately separating the British landmass from the rest of Europe. The Storegga Event, which triggered a tsunami reflected in sediment deposits in the northern North Sea, northeast coastlines of the British Isles and across the North Atlantic, was a major event during this transgressive phase. The spatial extent of the Storegga tsunami however remains unconfirmed as, to date, no direct evidence for the event has been recovered from the southern North Sea. We present evidence of a tsunami deposit in the southern North Sea at the head of a palaeo-river system that has been identified using seismic survey. The evidence, based on lithostratigraphy, geochemical signatures, macro and microfossils and sedimentary ancient DNA (sedaDNA), supported by optical stimulated luminescence (OSL) and radiocarbon dating, suggests that these deposits were a result of the tsunami. Seismic identification of this stratum and analysis of adjacent cores showed diminished traces of the tsunami which was largely removed by subsequent erosional processes. Our results confirm previous modelling of the impact of the tsunami within this area of the southern North Sea, and also indicate that these effects were temporary, localized, and mitigated by the dense woodland and topography of the area. We conclude that clear physical remnants of the wave in these areas are likely to be restricted to now buried, palaeo-inland basins and incised river valley systems.

Appraising the Development Potential of Ekofisk Over Tor Formation in the Halfdan Field, using a Multi-Disciplinary Approach to Well Planning and Applying Advances in Technology to Enhance Well Placement, Completion, Productivity and Recovery

2021 ◽  
Author(s):  
Anton Andreev ◽  
Michael Pitts ◽  
Andrew Hoover ◽  
Eyad Mohamed Elhassan ◽  
Felix Sebastian Bexkens ◽  
...  
Keyword(s):  
North Sea ◽  
New Technology ◽  
Seismic Signal ◽  
High Rate ◽  
Target Zone ◽  
Injection Wells ◽  
Well Placement ◽  
Horizontal Drain ◽  
4D Seismic ◽  
The Impact

Abstract Demonstrating a viable development for the Ekofisk reservoir directly above the producing Tor reservoir in the Halfdan Field (Danish North Sea) has historically been challenging. A recent well shows the value of cross-disciplinary collaboration and new technology to maximize recovery and mitigate reservoir and drilling risks. Specifically, 4D seismic was utilized when planning the well, while placement was optimized by using advanced geosteering tools. Well optimization was further enhanced by adopting novel completion and stimulation technologies. Pressure data and 4D seismic show that Tor and Ekofisk are in dynamic communication, but the degree of communication varies locally. The integration of 4D seismic with other disciplines’ input succeeded in optimizing the well placement and narrowed the significant pore pressure uncertainty along the 12,000-ft reservoir section. To maximize well length within the target zone and reduce the risk of being faulted out of the target reservoir deep resistivity was used to steer the well in the optimal layers. This contributed to 99% of the reservoir section being placed in the target zone. Lessons learnt from an earlier appraisal well and modest production experience in this part of the Ekofisk reservoir helped to justify the choice of selective completion zones (Sliding Side Door) in the inner part of the horizontal drain in order to minimize the impact of potential water or premature water breakthrough from high-rate injection wells located in the underlying Tor reservoir. This decision was validated after drilling the inner part of the well, where water-swept zones were encountered in the heel, followed by a long gas pay zone in line with 4D seismic signal in the remainder of the inner well section. To mitigate the risk of an unwanted fracture connection and increase contact with the tight oil-saturated reservoir, a novel stimulation and completion technology was successfully deployed in the outer 6-inch open-hole section of the well. The acid needles completion, deployed across a 3,000-ft reservoir interval and comprising 224 needles deployed by pumping acid, was the first installation of its kind in the Danish North Sea. For the acid needles completion, this installation holds two distinctions: the largest number of acid needles installed in a well, and the combination of the acid needles completion with a different completion system in a single lateral for the first time.

scholarly journals Multi-proxy evidence for the impact of the Storegga Slide Tsunami on the early Holocene landscapes of the southern North Sea

2020 ◽  
Author(s):  
Vincent Gaffney ◽  
Simon Fitch ◽  
Martin Bates ◽  
Roselyn L. Ware ◽  
Tim Kinnaird ◽  
...  
Keyword(s):  
North Sea ◽  
River System ◽  
Seismic Survey ◽  
Southern North Sea ◽  
North East ◽  
The North ◽  
Sediment Deposits ◽  
Land Mass ◽  
Storegga Slide ◽  
The Impact

AbstractDoggerland was a land mass occupying an area currently covered by the North Sea until marine inundation took place during the mid-Holocene, ultimately separating the British land mass from the rest of Europe. The Storegga Slide, which triggered a tsunami reflected in sediment deposits in the Northern North Sea, North East coastlines of the British Isles and across the North Atlantic, was a major event during this transgressive phase. The spatial extent of the Storegga tsunami however remains unconfirmed because to date no direct evidence for the event has been recovered from the southern North Sea. We present evidence that Storegga associated deposits occur in the southern North Sea. Palaeo-river systems have been identified using seismic survey in the southwestern North Sea and sedimentary cores extracted to track the Mid Holocene inundation. At the head of one palaeo-river system near the Outer Dowsing Deep, the Southern River, we observed an abrupt and catastrophic inundation stratum. Based on lithostratigraphic, macro and microfossils and sedimentary ancient DNA (sedaDNA) evidence, supported by optical stimulation luminescence (OSL) and radiocarbon dating, we conclude these deposits were a result of the Storegga event. Seismic identification of this stratum to adjacent cores indicated diminished traces of the tsunami, largely removed by subsequent erosional processes. Our results demonstrate the catastrophic impact of Storegga within this area of the Southern North Sea, but indicate that these effects were temporary and likely localized and mitigated by the dense woodland and topography of the area. We conclude clear physical remnants of the wave are likely to be restricted to inland basins and incised river valley systems.

A Historiography of the Impact of North Sea Oil on Northern Scotland

2007 ◽  
Vol 27 (First Serie (1) ◽  
pp. 81-97
Author(s):  
David Newlands ◽  
Alexandra Brehme
Keyword(s):  
North Sea ◽  
The Impact

Ten Demi-Culverins for Aldeburgh: Whitehall, the Dunkirkers, and a Suffolk Fishing Community, 1625–1630

2019 ◽  
Vol 58 (2) ◽  
pp. 315-337 ◽  
Author(s):  
Thomas Cogswell
Keyword(s):  
North Sea ◽  
East Coast ◽  
Central Government ◽  
Fishing Community ◽  
Close Attention ◽  
The North ◽  
The North Sea ◽  
The Impact

AbstractHistorians have not paid close attention to the activities of freebooters operating out of Dunkirk in the late 1620s. This essay corrects that omission by first studying the threat from Dunkirk to England's east coast and then addressing how the central government, counties, and coastal towns responded. A surprisingly rich vein of manuscript material from Great Yarmouth and particularly from the Suffolk fishing community of Aldeburgh informs this case study of the impact of this conflict around the North Sea.

On the Impact of the Operational Profile on the Ideal Design of a Diving Support Offshore Construction Vessel

2008 ◽  
Vol 45 (02) ◽  
pp. 77-88
Author(s):  
Erlend Hovland
Keyword(s):  
North Sea ◽  
Economical Analysis ◽  
Operational Profile ◽  
Working Day ◽  
The Impact ◽  
The Ideal

Simplified technical and economical analysis of a total of 12 different ship designs has been performed and compared with operational profiles of typical North Sea Diving and Construction vessels. Evaluation of what impact changes to the operational profile has on the best-suited vessel for the operation has also been performed. The paper focuses on optimizing the design to achieve a maximum of days in operation working day. Nomenclature

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

2016 ◽  
Vol 13 (3) ◽  
pp. 841-863 ◽  
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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