Jakob Haldorsen had a session at EAGE 2018 in Copenhagen:  Vertical-Seismic Profiling Using a Hybrid Tool, Combining Three-Component Geophones with DAS Sensors.

Abstract available here.

We introduce a VSP tool combining three-component geophones with Distributed Acoustic Sensing to the surface for optimum image resolution near the target with a maximized lateral image aperture. However, combining VSP measurements made by geophones with DAS data, it is important to realize the difference between a DAS sensor and a three-component geophone, and also between a DAS sensor and a single-axis geophone. We explore these
differences in order to create an optimum VSP image.