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Team:Lyon-INSA/microbialControl
From 2012.igem.org
Applications
The versatility of « Biofilm Killer »
“Biofilm Killer” is designed to meet several industrial needs, because although almost every industry has problems dealing with biofilm development, cleaning biofilms does not mean the same in the different industries. These applications can be briefly categorized in three different needs : completer ici !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Focus on Oil Industry
Oil industry faces with important and costly difficulties due to biofilm-related issues. These include, but are not limited to, pipeline and metallic structure corrosion, porosity clogging in the rock or the tubing, microbial souring, petroleum spoilage during storage. The main consequences of microbial at the global scale are several :
A reduced quality of the final product (microbial alteration), an increase in treatment costs (souring), the reduction of well production (souring, microbial alteration, clogging). Biofilm formation is involved in the corrosion of the metallic structures, including the oil-plateform, but most importantly the pipelines and tubing.
Biofilm-induced alteration will affect the structure, resulting in two effects :
The first one is the clogging of the tubing, which much like cholesterol deposit in our arteries, will reduce the available circulating space, reducing the flux of gas or oil that can be transporter in the pipe. Even small amounts of biofilm can negatively affect flow of hydrocarbons, as can be seen on the figure below in an experiment performed on gas fluxes in presence or absence of only 8% of biofilm coverage. As a consequence of biofilm formation, we can see that about 50% of the gas flux is lost (from Z. Augustinovic et al.).
The second is the anaerobic corrosion of the metal from the structure, which will be instrumental in establishing the biofilm and induce clogging, but will also fragilize the structures.
In the above example of biofilm-induced pipe corrosion, while a significant part of the corrosion occurs on the outside of the pipe, it is estimated that more than half of the corrosion is due to microbial growth on the inner surface of pipelines. Internal and external metallic corrosion contributes significantly to the risk of oil and gas pipeline deterioration and failure (see below), causes well and reservoir souring and plugging, and results in billions of dollars in annual costs to the oil and gas industry.
Impact of biofilms and microbiologically influenced corrosion in oilfield. Siri plateform (center) is located in the North sea and flanked by the smaller Cecilie and Nini satellite plateforms. Seafloor lines between the 3 structures and wells carry oil and gas (gas for lift and injection water for pressure support). INSET: in 2007, water injection line ruptured. Subsequent investigation revealed a mixture of iron sulfide and other corrosion by-products plus microbes and polysaccharide slime at the rupture site . These deposits allow sulfate-reducing procaryotes and other troublesome microbes to grow protected from biocides. (Augustinovic et al., Microbes- Oilfield Enemies or Allies? Oilfield Review, Summer 2012, Schlumberger)
Most importantly, failure on the production line can lead to dramatic oil or gas spills that lead to unprecedented environmental risks and damages. Such failure has recently happened on the Elgin Field, located in the North Sea ca. 240 kilometers off Aberdeen (Scotland), on a gas field exploited by the french potroleum company Total. The failure of the production line lead to a gas spill estimated to ca. 1.8 million euro loss per day for the company. Due to the location of the failure at the sea floor, it took several month for the leak to be stopped. In addition to the cost to the company, a maritime exclusion zone had to be created which perturbated maritime traffic, and ca. 20 tons of gas were released in the atmosphere daily. The previous year, in the same region an oleoduc exploited by the Royal Dutch Shell had ruptured also leading to oil spill in the North sea.
The problems with oil or gas production pipe is two folds : they are expected to be in place for decades and they often are difficult to access. Thus cleaning and locating biofilm is no simple task. Biofilms can be in dead zone which make them impossible to clean with mechanical process.
« Biofilm Killer »: a practical manual
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