Enzyme Enhanced Oil Recovery (EEOR): The Technology Principle
Updated: Aug 18
The innovative technology is based on a water soluble inert liquid enzyme concentrate with unique properties to interact in a catalytic fashion with hydrocarbons. "GreenZyme® is made using oil loving microbes where the oil digesting property is neutralized, and the ability to attach to and release hydrocarbons is kept".
The enzymatic function of GreenZyme® is due to the fact that the enzymes seek and release the oil, however they are NOT consumed in the releasing mechanism. Working in catalytic fashion with their activation energy, after the release of hydrocarbons the enzymes will be attached to the rock surfaces and be diffused and propagated in the water phase of the reservoir to reach further areas of oil-rock contact.
Accordingly, the enzymes are continuously available to interact with new hydrocarbons and continue to cause the release of oil.
GreenZyme® catalyzes reactions in the reservoir between the oil, water, and the rock surface.
An oil wet system is characterized by the major part of the rock surface being covered by oil. The oil releasing principle of the enzymes in such a system is due to the biological nature and catalytic action of the enzymes. It is very different from surfactants and microbes that are being used for EOR.
When the enzyme-water solution replaces the water phase in the system, the solid surfaces also become wetted by the enzyme-water solution. This drastically reduces the surface tension between oil and the water phase. In time, the enzyme will cause the release of oil droplets from the parent oil globule making the oil globule subject to be pushed out of the pore in the direction of flow.
The well stimulation process like huff and puff with the enzyme technology concentrate is very simple: Mix with water and apply. Since the enzymes are not consumed in the oil releasing process, they continue to act in low concentrations and as long as hydrocarbons are present and as they move into contact areas of oil and rock. The effect of the treatment enzymes could last for up to 36 months, which is the observed activity of each individual molecule. Ultimately, oil well intervention with this technology is economically extremely favorable to end users!
Independent Testing: University of Bergen, Norway
This mechanism was independently tested outside BTP in Hamidreza Nasiri's 2011 PhD dissertation at the University of Bergen's Centre for Integrated Petroleum Research. GreenZyme was one of several enzyme groups studied — alongside pure protease and esterase enzymes — across core-flood, micromodel, contact-angle, and interfacial-tension experiments on both sandstone and carbonate rock.
Flooding aged Berea sandstone and carbonate cores to residual oil saturation, then continuing with GreenZyme added to the brine, produced an additional 3–11% OOIP beyond a conventional waterflood. Micromodel imaging captured the same effect directly: enzyme-brine flooding redistributed trapped oil into smaller, more numerous droplets, consistent with the incremental recovery measured in the core floods.
The study's more surprising finding was about mechanism. Contact-angle measurements confirmed enzyme-treated brine shifted glass surfaces toward more water-wet conditions — in one series of tests, a mid-range 50° contact angle moved to 43° — and that shift tracked with the extra oil recovered. But the interfacial-tension reduction from GreenZyme, on its own, wasn't large enough to explain that recovery through capillary desaturation.
Nasiri's conclusion: wettability alteration, not IFT reduction, appears to be the dominant mechanism behind GreenZyme's core-flood performance in this study. The effect was also most pronounced on surfaces that started out moderately wet (contact angles between 60° and 100°) rather than on strongly oil-wet or strongly water-wet rock.
Sources & Credits
Nasiri, H. (2011). Enzymes for enhanced oil recovery (EOR) [PhD dissertation]. University of Bergen, Norway. Supervised by Kristine Spildo and Arne Skauge, Centre for Integrated Petroleum Research. Read via the University of Bergen's open research archive (BORA) or download BTP's hosted copy.
