This investigation applies 4-component ocean-bottom-cable (4-C OBC) seismic data across gas-producing trends of the Gulf of Mexico to the problem of distinguishing between commercial-gas reservoirs and low-saturation, noncommercial, fizz-gas reservoirs. Attributes of the P-SV mode are combined with calibration log data to classify high-amplitude P-P reflection anomalies into " high-saturation" and "reduced-saturation" categories. Two reservoir examples are provided as Figures 1 and 2. One example is a commercial-gas reservoir; the other is a fizz-gas reservoir. The gas saturation will not be defined for either example so the difficulty of distinguishing between the two types of targets can be appreciated.

Research data utilized in the study are provided by Devon Energy, Seitel Data, and WesternGeco. Funding is provided by EGL sponsors.

Figure 2. P-P and P-SV images of a gas reservoir with known water saturation.
Is this a commercial-gas or a fizz-gas reservoir?