A Brief History of the Shell "Soft Torque Rotary System" and Some Recent Case Studies

Abstract The Shell "Soft Torque Rotary System" (STRS) is a rotary drive control system that mitigates torsion vibrations in Oil and Gas drilling. The system was developed by Shell (with help from industry partners) in the early 90's and commercialised by licensing to a number of industry equipment suppliers. The original system was developed for DC drilling drives using analog torque feedback. The development of next generation AC top drives in the drilling industry has required a re-look and upgrade of the technology. Currently we have rejuvenated the technology and introduced stringent commissioning criteria to safeguard the quality of deployments around the globe. An overview of these developments will be given, seen from a Shell perspective. In addition a number of recent case histories will be presented. It is intended that the audience gets a good overview how the technology is being deployed in the Oil and Gas industry. The new integrated Soft Torque system is installed on 60 Shell operated drilling installations globally since 2009. Many good examples are now available demonstrating the benefit of the system and its excellent perfomance on also the AC top drives. Industry now has a tool at hand to help mitigate the occurence of stick slip and its detrimental effect on drilling performance, by way of controlling the top drive behaviour at surface. In combination with good drilling practices and drill string assembly design, it is now possible to avoid stick slip in a majority of drilling situations. Further work is ongoing (with our industry partners) to broaden the operating envelope of the system (into the deeper well sections and lower RPM range). Shell continues to champion the technology and fulfil a pro active role for quality control and further development of the industry/vendor partners.