Broadband and High Performance Vibroseis for high-density wideazimuth land acquisition

Summary

With the advent of high-channel count recording systems, one of the major hurdles for increasing spatial sampling density has been overcome. We are able to deploy dense receiver geometries with small group intervals and compact arrays or even point receivers. This allows us to record unaliased signal and noise and therefore do a much better job with noise attenuation during processing. We can then reap the full benefits of long offsets and wide azimuths for processing, imaging and reservoir. There is a need to match the increase in receiver density on the source side. To accomplish this in 3D land seismic we need a significant increase in source productivity while decreasing the source array size. Such productivity improvements can be created by spending less time per source point and by utilizing alternative source methodologies such as slip-sweep and blended acquisition.

The following challenge to deliver a clearer image and improved reservoir characterization is to emit and record broadband signals which offer better penetration and resolution. Our solution is to “performance-tune” the sweep to the vibrator’s mechanical and hydraulic limits. It extends bandwidth for a desired target output spectrum where low frequencies are enhanced, mid frequencies are unaffected and high frequencies retained or extended. In this presentation, we describe our successive technological leaps towards point source-point receiver seismic acquisition and illustrate it with recording and processing case studies from different regions of the world.

Key words::

• broadband
• high-density wide azimuth land acquisition
• high-channel count recording systems
• slipsweep
• blended acquisition