CANCELLED: Controlling helpful and harmful microbial activity for enhanced crude oil recovery

In mature oil fields, produced water is separated from produced oil and re-injected into the reservoir to maintain pressure. This produced water for re-injection (PWRI) often contains organics and free oil that stimulates unwanted microbial activity. While oil field operators typically use biocide to control microbial activity, some oil recovery methods require an active microbial component, excluding biocide use. Activated Environment for Recovery of Oil is one such an application. AERO enhances oil recovery by stimulating microbial growth in the subsurface. A small quantity of AERO nutrients, and sometimes air, are added to PWRI to stimulate microbial growth on oil trapped underground. However, AERO nutrients added to PWRI may also be consumed in the injection system by unwanted microbial growth on dissolved organics and oil. This possibility, along with the inability to use biocides, requires removing these compounds prior to nutrient addition. Combining in-house methods for stimulating oil field microbes with existing water treatment technology, we created a Moving Bed Biofilm Reactor (MBBR) process for PWRI. The method rapidly removes organics from PWRI under challenging oil field conditions such as variable salinity, oil carryover and solids precipitation. These design features enable biological water treatment even in difficult, highly variable water systems – a valuable capability for a broad variety of oil field and industrial applications. Used as part of an enhanced oil recovery system, the tandem pairing of our MBBR process and AERO nutrients permits selective control of microbial activity that enhance oil recovery while excluding unwanted microbial growth.