In this report ray tracing methods are used to study direct hydrocarbon indicators (DHI's or "bright spot" effects) for several common hydrocarbon structures. Zero-offset synthetic seismograms are constructed for anticline, normal fault, unconformity, reef, and sand lens models, both shallow and deep. It is found that polarity reversal, velocity pulldown, flat spots, and high amplitude are important DHI's. Deep hydrocarbon accumulations turn out to be much more difficult to detect than shallow ones, and gas is much easier to find than oil using direct hydrocarbon indicators.
STANFORD