Part 4: Compositional variations of North Sea formation waters

Abstract

AbstractA total of 236 individual water analyses from over 70 fields in the North Sea and Norwegian Haltenbanken area were provided by field operators or collated from the literature (Table 4.1). All the data from the field operators were supplied as representative analyses of the formation water for that field. Most of the analyses supplied were routine ten ion analyses with accompanying data on sample type, water resistivity and reservoir conditions. Where these accompanying data were not supplied but were available from other sources, they have been added to the original contribution. Previously published formation water analyses have also been included with accompanying data where available.Minor ions, such as bromide and lithium, trace metals, organic species such as acetate, and isotopic data were seldom reported. Consequently, maps and figures have only been constructed of the major cations, anions, total dissolved solids and Rw.All users of the water data compiled here should be aware of possible variations in data quality. There are a number of concerns, most notably the chemical analysis method, sampling artifacts and sample contamination.The majority of the chemical analyses of formation waters compiled were not performed by the North Sea field operators themselves, but were produced under contract by a number of service companies. Although routine laboratory methods were used to obtain the data reported here, different methods have been used between laboratories and over time due to improved instrumentation and analytical methods over the last 25 years of oil and gas production from the