A deviated well drilled during 2019 onshore Colombia used surface seismic amplitudes to help define the prospect. To complement logging-while drilling (LWD) and wireline logs, a checkshot survey was initially planned to deliver reliable time-depth data and decrease the uncertainty of the actual depth of target formations. An efficient solution was proposed consisting of a hybrid optical heptacable to record heterodyne distributed vibration sensing/distributed acoustic sensors (hDVS/DAS) vertical seismic profile (VSP) data while conveying the formation imager toolstring. This solution was favored over that deploying a conventional geophone tool. In addition to the basic checkshot data, excellent VSP data quality was recorded up to near surface, which leveraged the scope of the project to a 2D imaging VSP without additional acquisition time. Indeed, this was the first 2D migrated image from fiber-optic technologies for borehole seismic applications in South America. This migrated image over 6-80 Hz provided an accurate well-to-seismic tie including good=quality look-ahead reflection data to final well depth, in consideration that the survey was acquired from a point where the tools bridged while running in hole, nearly 1,000 ft away from TD. The total seismic acquisition was conducted in 55 minutes. No additional seismic logging was done in this well. Integration with borehole images and correlation with surface seismic revealed subseismic features well beyond initial objectives of the survey. The lessons learned in this study can be of interest and a benefit to the industry in several ways. Overall cost reduction of the seismic acquisition was achieved by saving rig time when performed simultaneously with another essential logging operation; this cost-effective technology may help geoscientists overcome resistance toward the cost associated with recording VSPs, effortlessly acquire more data, and avoid the usual seismic cancellation due to borehole conditions.
Presentation Date: Monday, October 12, 2020
Session Start Time: 1:50 PM
Presentation Time: 3:30 PM
Location: Poster Station 2
Presentation Type: Poster
