A post cold heavy oil production with sand (“CHOPS”) microbial enhanced oil recovery method comprises selecting a well having at least one wormhole and that has completed primary CHOPS production. When the reservoir does not contain enough of a gas producing indigenous microbe, an injectant is prepared comprising a gas-producing microbe, a nutrient suitable for the microbe, and a fluid base. The injectant is injected through the well and into the at least one wormhole in the reservoir; the well is shut in until pressure in the well reaches the target pressure; and then the well is produced.