FIG. 1.

Methane production from inoculated, crushed residual-oil-bearing core material incubated under different conditions as follows: (lines 1 and 2 [overlapping data]) inoculum in medium only and inoculum in medium with solvent-extracted core, (line 3) inoculum in medium with formation oil (0.06 g), (line 4) inoculum in medium with solvent-extracted core plus formation oil (0.06 g) plus 1 mM sulfate, (line 5) inoculum in medium with solvent-extracted core plus formation oil (0.06 g), and (line 6) inoculum in medium with whole core (no solvent extraction). These incubations contained 5 g core material and 10 ml medium. Error bars represent 1 standard deviation of the mean of triplicate incubations.