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Time-lapse borehole seismic surveys are a cost-effective alternative to traditional 4D surface seismic surveys for monitoring reservoirs and overburden. In Carbon Capture and Storage (CCS) projects, 4D Vertical Seismic Profiling (VSP) is a practical tool for tracking CO2 plume movement shortly after injection. With advancements in Distributed Acoustic Sensing (DAS) technology, most 4D VSP surveys now use permanently installed fibre optic cables, which lowers operational costs and enhances measurement repeatability. Onshore VSP typically relies on vibroseis sources, but challenges like complex terrain and seasonal ground conditions can affect repeatability. A permanent seismic source below the weathering zone is needed for reliable, cost-effective monitoring in CCS and oil and gas projects.
The Surface Linear Vibrator (SLV) is a small, easy to install (and remove) seismic source, which is less affected by changes in ground conditions and is capable of phase-controlled sweeps. Here, we describe the results of a borehole seismic field test of an SLV which is deployed on a buried helical anchor for permanent and continuous seismic monitoring.