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Environmental Monitoring and Assessment

, Volume 167, Issue 1–4, pp 7–16 | Cite as

Impacts on seafloor geology of drilling disturbance in shallow waters

  • Iran C. S. Corrêa
  • Elírio E. ToldoJr
  • Felipe A. L. Toledo
Article

Abstract

This paper describes the effects of drilling disturbance on the seafloor of the upper continental slope of the Campos Basin, Brazil, as a result of the project Environmental Monitoring of Offshore Drilling for Petroleum Exploration – MAPEM. Field sampling was carried out surrounding wells, operated by the company PETROBRAS, to compare sediment properties of the seafloor, including grain-size distribution, total organic carbon, and clay mineral composition, prior to drilling with samples obtained 3 and 22 months after drilling. The sampling grid used had 74 stations, 68 of which were located along 7 radials from the well up to a distance of 500 m. The other 6 stations were used as reference, and were located 2,500 m from the well. The results show no significant sedimentological variation in the area affected by drilling activity. The observed sedimentological changes include a fining of grain size, increase in total organic carbon, an increase in gibbsite, illite, and smectite, and a decrease in kaolinite after drilling took place.

Keywords

Geological data collections Offshore exploration Environmental monitoring Campos Basin Brazil 

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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Iran C. S. Corrêa
    • 1
  • Elírio E. ToldoJr
    • 1
  • Felipe A. L. Toledo
    • 2
  1. 1.Centro de Estudos de Geologia Costeira e Oceânica, Instituto de GeociênciasUniversidade Federal do Rio Grande do SulPorto AlegreBrazil
  2. 2.Instituto Oceanográfico, IO-USPPraça do OceanográficoSão PauloBrazil

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