Shake and Go - Advances in Vibroseis Technology

Abstract

Abstract A new patented vibroseis acquisition method, Shake and GoSM, allows operation of multiple vibrators at multiple source points simultaneously and continuously with no waiting for between-sweep listening times or for between-vibrator slip times. This method allows for unsurpassed production rates. Model simulations, field gathers, and processed stacks are used to demonstrate excellent data quality compared to other high productivity methods. The cost of vibroseis land acquisition is directly related to the time it takes to shake each vibrator point and move to the next point. Shake and Go can be used to record seismic data at lower cost, or it can be used to record more data at the same cost with improved sampling of signal and noise. It is especially efficient for new point source and point receiver (MEM) acquisition without arrays. Shake and Go, also called C-HFVSSM or Continuous High Fidelity Vibrator SeismicSM, uses long segmented sweeps and HFVS separation. Measurements of the individual vibrator motion are recorded and used to derive a filter that optimally recovers individual seismograms from vibrators operating simultaneously. Cross contamination from strong events, which are simultaneously recorded, are not observable in the individual recovered seismograms. Interference and harmonic noise from the continuous sweeping are limited to the end of a long record and can be removed with a new novel processing method. Because of the high production rates and high data quality, the new method is expected to dominate land acquisition in the future. We present analysis of the noise and show data comparisons for different vibroseis methods. We also overcome the limitation that there must be as many sweeps as vibrators or time delays to optimally separate records for simultaneous sourcing. Methodology Shake and Go or Continuous-HFVSSM (C-HFVSSM) is a combination of ExxonMobil's HFVS (High Fidelity Vibratory Seismic) method and its proprietary Cascaded-Sweep technique. Both acquisition methods, HFVS and its super high efficiency version C-HFVS are licensed to a number of contractors. We have recently developed a proprietary processing method (patent application filed) to further improve the quality of the C-HFVS method so that it matches the high quality of HFVS and allows us to exploit super high efficiency acquisition without any compromise in data quality.