Imaging Salt Flank by a Rig-source VSP
Event name: Fourth EAGE Borehole Geophysics Workshop
Session: Innovation In Processing And Imaging
Publication date: 19 November 2017
Info: Extended abstract, PDF ( 379.15Kb )
Price: € 20
Accurately delineating a salt flank or base is critical to evaluate the extent of reservoir rock and to successfully place development wells in many salt-trap oil reservoirs. Due to the severe distortion and obstruction of seismic waves by the salt body, surface seismic imaging often fails to clearly define the salt flank or base boundary. Borehole seismic salt proximity surveys have historically played an important role in delineating and mapping the salt flank/base adjacent to a borehole by either calculating the salt exit points from first break travel times or directly migrating the first arrival waveforms. In a conventional SPS, a seismic source is positioned above the salt body. In an offshore environment, deploying a source boat adds significant cost for the acquisition of a conventional SPS. Through modelling a real case of rig-source VSP survey, this paper suggests for certain salt-trap reservoirs such as those in Gulf of Mexico, a rig source VSP can also serve as a salt proximity survey to delineate the salt flank as done by a conventional offset source SPS. By removing the need to deploy a source boat, a rig-source SPS is more efficient and cost-effective than a conventional offset-source SPS.