oa Significant VSP data quality improvements through the use of a broadband source

Seismic vibrators are the preferred sources for land vertical seismic profile (VSP) surveys as they are relatively repeatable, controllable, have high energy, have a low environmental impact, and are cost-effective. Unfortunately, due to the mechanical and hydraulic constraints of the vehicles, the typical swept bandwidth has been quite limited, typically of the order of 3 octaves. In this paper we show that dramatic improvements in seismic data quality can be achieved by extending the bandwidth used for Vibroseis VSPs. These increases are dependent, however, on the use of modern vibrators, specialised low-frequency enhancing sweeps, and downhole sensors with an extended frequency response range.