Introduction

Shallow seismic reflection techniques have proven effective at imaging shallow and relatively small targets in a variety of geologic settings (Pullan and Hunter, 1990; Jongerius and Helbig, 1988; Miller et al., 1989; Miller et al., 1995; Shtivelman et al., 1998). Laterally extensive zones of shallow gas have been easy targets to detect but a hindrance to many shallow high-resolution seismic reflection surveys (Pullan et al., 1998). High amplitude reflections associated with the boundary between gas-bearing zones (sands) and cap rocks (shale) are routinely referred to as “bright spots” (Khattri et al., 1979). Offset dependent reflection amplitude (Amplitude Versus Offset [AVO]) characteristics for gas rich sediments can vary significantly with geologic setting, gas concentrations, and lithology (Ostrander, 1982). Three unique types of reservoirs or classes of gas deposits have been described that incorporate geology setting and lithology with seismic attributes (Rutherford and Williams, 1989).

This content is only available via PDF.
You can access this article if you purchase or spend a download.