Adsorption of EOR chemicals under laboratory and reservoir conditions, part II: Bacterial reduction methods
Abstract
We have successfully performed bacterial reduction of an iron-containing outcrop sand sample under static conditions using Shewanella genus bacteria. Adsorption of an anionic (alkyl benzyl sulfonate) surfactant was around 7-times lower on treated outcrop samples. Most of this reduction (∼3X) occurs over the first 3-4 days of incubation, contemporaneously with iron dissolution and limited biofilm formation. Continued incubation after this point attends the formation of significant biofilm, as well as a continued decrease in surfactant adsorption. Non-iron-reducing bacteria also formed biofilm on outcrop samples, yielding a significant (though smaller) decrease in surfactant adsorption. Microscopy demonstrates preferential attachment of biofilm to iron minerals in a heterogenous outrop sample. Repeated rinsing results in a removal of biofilm formed by iron-reducing or bacteria and a corresponding increase in surfactant adsorption to about 1/3 to 1/2 of original levels. This proof of concept for a bacterial core restoration method using iron-reducing bacteria is considered successful, with the caveat that care must be taken to minimize and/or remove biofilm in order to avoid biofilm-related artifacts. Implications of these results for the determination of reservoir rock-fluid properties in biologically-active reservoirs are also discussed
Keywords
Removal of biofilms
Enhanced recovery
Surfactant adsorption
Restoration methods
Reservoir conditions
Adsorption
Bacteria
Biofilms
Iron
Oil well flooding
Petroleum engineering
Petroleum reservoir evaluation
Petroleum reservoirs
Surface active agents
Bacterial reduction
Biofilm formation
Iron reducing bacteria
Preferential attachments
Domains
Life Sciences [q-bio]
Origin : Files produced by the author(s)
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