Reconstruction of Salt Tectonics: Insights from the Mid North Sea High

Author(s):  
Chibuike Nnadi ◽  
Alexander Peace

<p><strong>Abstract</strong></p><p>The North Sea is a complex rift system that has undergone a polyphase evolutionary history from the Palaeozoic to Recent, including the deposition, and subsequent mobilisation of Upper Permian Zechstein salt. This halokinesis has played an integral role in the geologic evolution of the North Sea, controlling the present-day structural style. The driving mechanisms and kinematics of salt deformation have gained widespread interest partly due to the potential role of salt in hydrocarbon systems, and also due to its potential uses for nuclear waste disposal. However, the primary driving mechanism for salt-related deformation in the North Sea is debated. Here, we focus on the Mid-North Sea High (MNSH), an area of the North Sea in which salt-related deformation is widespread. We interpret open access data made available by United Kingdom Oil and Gas Authority (OGA) including 2D seismic reflection, gravity, magnetic and well data in Petrel, followed by forward modeling and restoration in the MOVE software. The results show that, the style of salt-related deformation in the MNSH region is highly variable, with the influence of local stratigraphy, as well as basement structures, also contributing to the deformation style.</p><p><strong>Keywords:</strong> Salt tectonics, Halokinesis, North Sea, Mid North Sea High</p>

BMJ Open ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. e037558
Author(s):  
Anne Waje-Andreassen ◽  
Øyvind Østerås ◽  
Guttorm Brattebø

ObjectivesFew studies have described evacuations due to medical emergencies from the offshore installations in the North Sea, though efficient medical service is essential for the industrial activities in this area. The major oil- and gas-producing companies’ search and rescue (SAR) service is responsible for medical evacuations. Using a prospective approach, we describe the characteristics of patients evacuated by SAR.Design and settingA prospective observational study of the offshore primary care provided by SAR in the North Sea.MethodsPatients were identified by linking flight information from air transport services in 2015/2016 and the company’s medical record system. Standardised forms filled out by SAR nurses during the evacuation were also analysed. In-hospital information was obtained retrospectively from Haukeland University Hospital’s information system.ResultsA total of 381 persons (88% men) were evacuated during the study period. Twenty-seven per cent of missions were due to chest pain and 18% due to trauma. The mean age was 46.0 years. Severity scores were higher for cases due to medical conditions compared with trauma, but the scores were relatively low compared with onshore emergency missions. The busiest months were May, July and December. Weekends were the busiest days.ConclusionThree times as many evacuations from offshore installations are performed due to acute illness than trauma, and cardiac problems are the most common. Although most patients are not severely physiologically deranged, the study documents a need for competent SAR services 24 hours a day year-round. Training and certification should be tailored for the SAR service, as the offshore health service structure and geography differs from the structure onshore.


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