Conventional oil recovery and now the access to unconventional “tight” oil and gas require the use of large amounts of water. Typically, this water will contain microbial contaminants. Some of these microbes, such as the SRB species, will cause downhole corrosion and the reservoir to become soured.
Neptune Benson solutions are designed for high corrosion susceptible applications, Neptune Benson can manufacture from Duplex 254 steels that are specifically enhanced to prevent corrosion.
Varieties of species are able to survive in oxygen rich (aerobic) water, or in the oxygen starved (anaerobic) environments. Aerobic bacteria can convert iron from the ferrous (Fe2+) to the ferric (Fe3+) state, and produce ferric hydroxide (Fe [OH]3), which is highly insoluble and causes formation damage. Iron oxidizing bacteria can form slimes that will develop mats of high-density slime that will begin to cover surfaces. If allowed into the well, they shield corrosion forming bacteria colonies from chemical bactericides and plug the pores of the matrix holding the oil.
Anaerobic species, such as Sulfate Reducing Bacteria (SRB’s), can convert sulfate or sulfite that is naturally occurring and present in a variety of drilling muds, into hydrogen sulfite (H2S). When combined with iron, iron sulfide is formed which is very costly to remove. In addition, SRB species can cause pitting corrosion of steel. Elevated H2S increases the corrosiveness of the water, which increases the possibility of hydrogen blistering, sulfide stress cracking, and can lead to costly sweetening of sour oil.
To protect against SRBs, ETS-UV systems are usually installed following filtration of the water to remove suspended solids. As filters can often be a source of microbial growth, ETS-UV equipment is best-located post filtration and before the high lift pumps or chemical injection stages.
- Enhanced Oil Recovery
- Seawater Treatment for downhole injection
- Pipeline Hydro-test water
- Hydraulic Fracturing Water Treatment