Decoding the water flooding processes from produced water composition - A case study from the Halfdan chalk oil field, Danish north sea

N. H. Schovsbo, H. Holmslykke, C. Kjøller, L. Kristensen, K. H. Esbensen, A. Y. Halim, S. N. Gottfredsen, K. L. Feiberg, S. M. Nielsen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingspeer-review

2 Citations (Scopus)

Abstract

Analysis of produced water is one of few direct sources of information to the subsurface processes active in an oil field. However, revealed geochemical patterns are typical complex and require a multidisciplinary approach to successfully unlock and decode. The Halfdan field initially contained two main types of formation brine but now, after 15 years of extensive water flooding, the field contains mostly a seawater modified type. The initial water was a low salinity sulphate-depleted type and a medium high saline sulphate-rich type that varied in a geographically systematic manner. The water treatment resulted in a net deposition of sulfate and Mg and a net export of Ca and Cl ions from the field. This pattern is similar to core flooding results, suggesting that a substantial alteration of the wettability of the chalk occurred. Spatial and temporal variation in water composition are mapped based on 3880 analysis from 75 wells and are related to water flooding history and sweep efficiencies obtained from 4D seismic. Produced water analysis is thus an important asset for designing water sweep in mature fields. Furthermore knowledge about the initial water types may optimize water treatment and prediction of geographically distribution scale and corrosion risks.

Original languageEnglish
Title of host publication79th EAGE Conference and Exhibition 2017
PublisherEuropean Association of Geoscientists and Engineers
ISBN (Electronic)9789462822177
DOIs
Publication statusPublished - 2017
Event79th EAGE Conference and Exhibition 2017: Energy, Technology, Sustainability - Time to Open a New Chapter - Paris, France
Duration: 12 Jun 201715 Jun 2017

Publication series

Name79th EAGE Conference and Exhibition 2017

Conference

Conference79th EAGE Conference and Exhibition 2017: Energy, Technology, Sustainability - Time to Open a New Chapter
Country/TerritoryFrance
CityParis
Period12/06/1715/06/17

Programme Area

  • Programme Area 3: Energy Resources

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