On land or offshore, kick detection is primarily achieved by means of measurement and observation atrnsurface of the drilling fluid and drilling equipment1. A kick, if not controlled, will progressively grow inrnthe wellbore until it becomes a blowout. Control of a kick is dependent upon time-to-detection. Kickrndetection in a subsea well is more problematic because the subsea well contains a large volume of drillingrnfluid between the wellbore and the surface kick detection – the volume of mud in the riser – which canrnmask a kick or delay detection. This additional volume in the riser may be up to twice as much as thernvolume in the wellbore. In any case, control of a kick in a subsea well can be improved if detection ofrnthe kick can be made sooner.rnIn this work an investigation was made to develop kick detection sensors that could work at the subsearnmudline. By detecting kicks just above the wellhead, at the base of the subsea riser, the time for correctivernaction can be increased by as much as a factor of three. Two sensors, ultrasonic and hydrostatic, wererntested to detect changes in the fluid density caused by the presence of oil, gas, or water in the drilling fluid.
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