Enhanced Oil Recovery through Microbially Induced Calcium Carbonate Precipitation

Mobility contrasts between oil and water, along with permeability heterogeneity, lead to fingering instabilities that impede the recovery of hydrocarbons from the subsurface. Here, we present a novel, improved oil recovery approach, whereby microbially induced carbonate precipitation (MICP) reduces the local permeability of water-saturated preferential flow paths to improve the overall sweep of the reservoir. With MICP, local pore geometry in preferential pathways is altered to divert successive injection fluids to oil-saturated pores. We demonstrate the feasibility of the approach using a silicon microfluidic device with etched geometries representative of real rock pores, where a ∼5% reduction in the local porosity of water-swept regions increased overall oil recovery by ∼28% original oil in place (OOIP). We performed sensitivity analysis on the injection conditions required to maximize oil recovery and bacterial growth. Overall, we show that calcium carbonate grains grown using MICP can provide a secure and stable method to control fluid flow in situ and recover additional hydrocarbons to provide an avenue for cost-effective and environmentally benign hydrocarbon extraction.