In more recent times, due to the temporary nature of well stimulation, specialized drilling ships known as "well stimulation vessels" have been used for deep sea well stimulation. Offshore companies such as Norshore and Schlumberger operate a fleet of such specialized ships.[1] Also known as "Multipurpose drilling vessels", these ships replace the conventional drilling oil rig, thus resulting in considerable savings in cost.[3] Some WSV's such as the "Norshore Atlantic" are able to perform multiple tasks including riserless operation in the shallow- and mid-water segments, drilling complete oil wells and performing complete subsea decommisioning (P&A). They are also able to perform pre-drilling of the top hole sections in deep water and well intervention operations with workover risers.[4][5]