Massive 3D VSP® Facts

Massive 3D VSP® Overview Presentation - 1.9 MB PDF file

• Massive 3D VSP's® significantly increase the resolution of 3D images compared to surface seismic surveys. The use of downhole receivers usually results in the doubling of the useful seismic frequency bandwidth as compared to the use of surface receivers. The reason for the doubling of the bandwidth is that the seismic waves recorded on downhole receivers only travel once through the highly attenuating weathering layer.



• Massive 3D VSP's® can generate high-resolution images below complex seismic structures, such as salt bodies. The seismic wave only has to travel through the complex velocity structure once and by placing the receivers below the complex velocity structures the downhole receivers will pick up the reflection energy with very little additional attenuation and frequency loss.
• Massive 3D VSP's® can be used to overcome some of the imaging problems generated by high velocity contrast layers like basalts, anhydrites, and permafrost, which cause loss of reflection signal strength and generate interfering multiples.
• Massive 3D VSP's® are recording 3-component seismic signals with high vector fidelity. All seismic modes P-P, P-S, S-P and S-S are recorded with a minimum of distortion. High resolution P-S converted wave mode imaging can be accomplished on-shore and off-shore. High vector fidelity recording of shear wave splitting allows estimation of fracture orientation.
• Massive 3D VSP's® provide excellent velocity control near the receiver wells. Accurate velocity profiles can be obtained directly from the VSP data and used to build 3D velocity models for accurate depth imaging.
• Massive 3D VSP's® provide reliable estimates of anisotropy parameters, by measuring quantities that are not recorded in surface seismics. When both sources and receivers are restricted to the surface it is difficult to un-ambiguously estimate anisotropy parameters as a function of depth. Anistropy parameters specified in depth are necessary for a 3D velocity model for 3D depth migration.
• Massive 3D VSP's® can be used in areas where large seismic sources are restricted. Examples include sensitive marine environments or urban areas. Because the seismic wave only has to travel once through the highly attenuating near-surface weathered layers, much less source energy is required. In some places up to five times less source effort is needed than for surface seismic.
• Massive 3D VSP's® typically are faster, cheaper, and enviromentally less intrusive then surface seismic surveys.