− | Evaporative loss can affect the appearance of gas chromatograms. When the solvent is removed too fast during recovery of source rock extracts, selective loss of some of the C<sub>15+</sub> components can occur. This loss not only alters the appearance of the gas chromatograms but may also change compound ratios (for example, the [[pristane-phytane ratio]] through selective loss of pristane). In some instances, gas stripping in the reservoir can selectively remove lighter components, leaving an oil or residue that looks lightly [http://www.oiltracers.com/services/exploration-geochemistry/oil-biodegradation.aspx biodegraded] or, in some instances, waxy. | + | Evaporative loss can affect the appearance of gas chromatograms. When the solvent is removed too fast during recovery of source rock extracts, selective loss of some of the C<sub>15+</sub> components can occur. This loss not only alters the appearance of the gas chromatograms but may also change compound ratios (for example, the [[pristane-phytane ratio]] through selective loss of pristane). In some instances, [http://www.gazprominfo.com/terms/topping-gas/ gas stripping] in the reservoir can selectively remove lighter components, leaving an oil or residue that looks lightly [http://www.oiltracers.com/services/exploration-geochemistry/oil-biodegradation.aspx biodegraded] or, in some instances, waxy. |
− | [[:file:oiloil-and-oilsource-rock-correlations_fig8-16.png|Figure 12]] shows a gas chromatogram of an oil whose light ends were partially removed during gas stripping in the reservoir. Oils like this one are often observed in deep reservoirs in [[Tertiary]] deltaic sequences. | + | [[:file:oiloil-and-oilsource-rock-correlations_fig8-16.png|Figure 12]] shows a gas chromatogram of an oil whose light ends were partially removed during [http://www.gazprominfo.com/terms/topping-gas/ gas stripping] in the reservoir. Oils like this one are often observed in deep reservoirs in [[Tertiary]] deltaic sequences. |