Near-surface, SH-wave surveys in unconsolidated, alluvial sediments

The past decade of hydrocarbon exploration has been marked by sweeping technological innovations that have greatly advanced methods for exploration and development of oil and gas reserves. An example of major importance is the use of shear waves in marine oil and gas exploration to image reflectors beneath gas chimneys. This technology grew from infancy to maturity in the 1990s, is now incorporated into commercial processing packages, and is being used with success in a number of situations. Recent SEG Annual Meetings and the Special Section of this issue of TLE have had many documented case histories about the use of converted ( P-SV ) waves. The SH -wave (another type of shear wave), however, has been of less interest to the energy industry during the past decade. Near-surface applications of SH -waves, in contrast, have received increasing attention. The present article briefly reviews shear-wave technology advances made in the energy industry over the past decade that prepared the way for the present near-surface application of SH -waves. The article concludes with a near-surface case study using combined P - and SH -wave interpretation in an unconsolidated, alluvial setting. A shear wave having particle motion in a horizontal direction is called an SH -wave. It stands in contrast to an SV -wave, for which particle motion is in the vertical plane. SH -waves travel the entire path from source to receiver as shear waves, but recorded SV -waves commonly start as P -waves at the source and are converted to SV -waves by reflection along the way. SH -waves had their energy industry heyday in the late 1980s and early 1990s after an extensive field study directed by Conoco (the Conoco Group Shoot) and supported by many oil companies (Domenico and Danbom, 1987). That study spurred interest in the imaging potential of …