Crosswell seismic imaging of acoustic and shear impedance in a Michigan reef

摘要

Crosswell seismic imaging has demonstrated its ability to provide extremely high-quality images of reservoirs such that internal features within the reef can be imaged and character-rnized. Resolution is about 40 times that of surface seismic in the same area (50 Hz versus 2000 Hz).rnThe amplitudes of reflectors from within the Springdale reef are low, however, and especially so for the image obtained from above. We attribute this to attenuation and scattering of signal as it passes through the complex upper part of the reef, where gas saturation likely varies locally, reservoir pressure is extremely low, and structural complexity of the reef is evident. The image from beneath does not pass through this complexity and only experiences the gas saturation and low pressures at the upper edge of the image, allowing most of the image to be higher quality.