Generally, microbial enhanced oil recovery (MEOR) recovers less of the remaining oil in place than other chemical EOR processes, both in the laboratory and the field. Efforts to explain this difference are limited by the lack of quantitative measures of microbial performance (e.g., reaction rates, stoichiometry, and required product concentrations). However, it is possible to demonstrate quantitative relationships between microbial performance, reservoir characteristics, and operating conditions (e.g., well spacing, injection rates, and residual-oil saturation).