The prevalence of viral hepatitis in Norwegian merchant seamen in overseas trade was studied in 523 volunteers during compulsory health control before embarkation from the port of Oslo. The prevalence of hepatitis B markers was 9.4%, which is significantly higher than in the general Norwegian population. The prevalence increased with the number of years of occupation. It was associated with frequent casual sexual contacts in foreign countries, but not significantly increased in participants who had been exposed to tattooing or different types of medical treatment under poor hygienic conditions in foreign areas. The prevalence of antibodies against hepatitis A (HAV) was 36% in seamen born in 1945 or earlier and 5% in younger individuals, an age-dependent pattern which is essentially similar in the general Norwegian population. However, the prevalence of hepatitis A antibodies seemed to increase with years in foreign trade. The incidence of viral hepatitis infections in the occupation was noticeably high, suggesting that vaccination of seamen in certain areas of trade should be considered.
Automated drilling has been discussed for a long time, with much of the discussion being around future ambitions – what could be or might be possible. Given the complexity of a modern drilling operation, the idea of automating all or part of it is daunting. Despite the apparent obstacles, there has recently been significant progress toward this goal, centred on the core process of drilling new boreholes. This paper presents an automated directional-drilling process executed on a commercial well in the Norwegian sector of the North Sea in 2019, where a next-generation intelligent rotary-steerable system completed a well section in a single run with all drilling commands automatically computed, optimized, and downlinked by a drilling automation platform. The section was complex, comprising two intervals requiring steering in three dimensions, separated by a tangent section. Directional-drilling engineers onshore, who had the authority to override the system if necessary, supervised the operation remotely. No such override was required, and the automated system was able to drill the entire section while automatically sending steering decisions. The 12¼-in. landing interval required precise positional control to enter the reservoir in the correct location and with the correct attitude. At the end of the section, with over 1500 m drilled, the final well position was 0.28 m above the target position and 3.89 m to the left, with minimal tortuosity, making it easy to land the subsequent casing string. The final build section, from 33 to 71.6° of inclination, was drilled between 100 and 150 m/hr, with a planned dogleg severity of 3°/30 m. To drill such a complex trajectory automatically would have been unthinkable only a short time ago and marks a major milestone in the development of automated drilling technology.
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