Microbial manipulations of surfactant-containing foams to reduce subterranean formation permeability

A process for plugging a permeable subterranean stratum which comprises:

• isolating bacteria from stratum waters;
• developing competency to degrade a surfactant by growing the bacteria with the surfactant present as the sole organic nutrient;
• starving the resulting competent bacteria until the cells reach a diameter less than about 0.4 .mu.m;
• injecting the produced ultramicrobacteria into the stratum;
• and
• injecting a foam containing the surfactant into the stratum, the surfactant being operative to lower the surface tension of the foam bubbles so that the foam will penetrate the stratum;
• such that the ultramicrobacteria will resuscitate to the vegetative state and degrade the surfactant to effectively plug the stratum.

A process for microbially enhanced oil recovery for plugging permeable subterranean strata in an oil-producing formation, which comprises:

• isolating bacteria which produce expolysaccharide biofilm from formation waters;
• developing competency to degrade the surfactant petroleum sulphonate by growing the bacteria with said surfactant present as the sole organic nutrient;
• starving the resulting competent bacteria until the cells reach a diameter less than about 0.4 .mu.m;
• mixing the produced ultramicrobacteria with a foam containing said surfactant;
• and
• injecting the mixture into the formation before resuscitation of appreciable numbers of the UMB can take place;
• such that the ultramicrobacteria will resuscitate to the vegetative state and degrade enough of said surfactant to effectively plug the permeable strata together with the biofilm produced by the vegetative cells.