Article Figures & Data
Figures
- 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.
- FIG. 2.
(A) n-Alkane consumption and methane production in crushed residual-oil-bearing core incubations. Closed triangles, n-alkane-to-standard peak area ratio in inoculated residual oil cultures; open triangles, n-alkane-to-standard peak area ratio in uninoculated and sterile controls; closed circles, methane production in inoculated residual oil cultures; open circles, methane production in uninoculated residual oil incubations. (B) Total ion chromatograms showing the consumption of n-alkanes over 4 months when crushed residual-oil-bearing core material was inoculated with a methanogenic, hydrocarbon-degrading consortium. Pr, pristane; Ph, phytane; C24D50, extraction standard; S8, sulfur.
- FIG. 3.
(A) Methane production from inoculated crushed residual-oil-bearing sandstone core incubations in the absence (closed circles) or presence (open circles) of exogenously added sulfate. Open triangles represent the sulfate concentrations in the sulfate-amended incubations. (B) Methane production from inoculated residual-oil-bearing sandstone core incubations at different salinity levels. Squares, no added NaCl; circles, 1% NaCl; triangles, 2% NaCl. Error bars represent 1 standard deviation of the mean of triplicate incubations.
- FIG. 4.
Phylogenetic relationships of eubacterial clones from the oil-utilizing methanogenic consortium with respect to related sequences. The tree is constructed from approximately 800 bp 16S rRNA gene sequence using the neighbor-joining algorithm. One thousand bootstrap replications were performed; only values greater than 750 are shown. The numbers in parentheses following the accession numbers indicates the total number of clones represented by the OTU.
- FIG. 5.
Methane production from six different inoculated petroliferous rocks sampled from different formations in Oklahoma relative to an inoculum-only control (line 7). Line 1 represents the sandstone core obtained from Nowata County. Core samples 2 to 6 (lines 2 through 6) are described in the text in Material and Methods. Error bars represent 1 standard deviation of the mean of triplicate incubations.
