Seawater is injected into oil-reservoirs to push oil towards the production wells. Unfortunately, seawater contains sulfate, which is converted to the harmful gas H2S by prokaryotes, singled-celled organisms without a cell nucleus, within the oil-bearing formations of ancient rocks in the underground. The production of H2S can be suppressed by adding nitrate to the seawater before it is pumped into the sub-surface. Several models for how this suppression might function exist, but it is not clear which one is correct. Our aim is to better understand the mechanisms by which injection of nitrate into producing oilfields can limit the microbial production of H2S, and thereby optimize use of nitrate as a H2S production countermeasure in the oil industry.
The project is a cooperation between Aarhus University, The Danish Technical University and the energy company TOTAL, and is funded by the Danish Center for Oil and Gas.