Improving Vertical Seismic Profile Safety Through the Use of Specially Designed Source Vehicles

Abstract

Abstract Two successive models of truck-mounted seismic vibrators were designed and manufactured to ensure the highest possible levels of vehicle safety while also delivering excellent data quality. Seismic vibrators are the preferred energy sources for land vertical seismic profile (VSP) surveys because they are relatively repeatable and controllable, have high energy but a low HSE impact, and are cost effective. Recent advances in vibrator design have enriched the quality of VSP data, but the improvements have been mainly applied only to buggy-mounted vibrators. Buggy-mounted vibrators are typically used for surface seismic surveys in remote areas, and thus their design has been optimized for off-road performance. Surface seismic surveys have typical durations of a number of months or even years. However, VSP surveys are often of short duration (several hours) and require rapid equipment mobilization to the wellsite, often at short notice. Seismic vibrators for vibroseis VSP surveys may spend more time in road transportation to and from the wellsite than in performing the actual VSP survey. While the main HSE safety exposure for buggy-mounted vibrators is related to their off-road use, the main exposure for the vibrators used in VSPs is related to their transport between work sites and their use by sometimes relatively inexperienced personnel (vehicle weights can be more than 30 tons and hydraulic pressures often exceed 3,000 psi). As the targets for VSP surveys become more complex, there is a need to use more advanced vibrators, which until now have only been available as buggy mounted. However, the use of buggy-mounted vibrators for VSP surveys has HSE implications for transportation. To overcome these issues, the special truck-mounted vibrators that have been developed incorporate all the recent improvements in vibrator quality while retaining all the HSE advantages of modern truck-mounted vehicles, such as their ability to be driven safely between wellsites, and additional modifications to ensure the safety of personnel with limited experience. One of the greatest HSE exposure risks associated with vibroseis VSP operations occurs during transportation to and from wellsites. Since the introduction of the new vehicles, there have been no HSE incidents.