Abstract:
On land or offshore, kick detection is primarily achieved by means of measurement and observation at surface of the drilling fluidand drilling equipment. A kick, if not controlled, will progressively grow in the wellbore until it becomes a blowout. Control of a kick is dependent upon time-to-detection. Kick detection in a subsea well is more problematic because the subsea well contains a large volume of drilling fluid between the wellbore and the surface kick detection –the volume of mud in the riser – which can mask a kick or delay detection. This additional volume in the riser may be up to twice as much as the volume in the wellbore. In any case, control of a kick in a subsea well can be improved if detection of the kick can be made sooner. Automating the initial well control response to an influx is the initial focus area with the goal of assisting rig personnel to identify and stop any influx without delay. This will lead to a well control automation collaboration project being initiated between an operator, a rig contractor and a rig equipment supplier. The first phase of the project is to develop a system that could detect an influx across a broad spectrum of well construction related rig operations. To understand where to focus the kick detection system upgrade efforts, a fault tree style sensitivity analysis of kick detection and well shut-in procedures will be undertaken. The results will point to the high value of improved sensor data (both accuracy and reliability) and of improved detection software for alarming (both in terms of coverage and how the driller is alerted to respond to a confirmed kick condition). Based on this sensitivity analysis, a kick detection system upgrade functional specification will be created and used to develop a trial upgrade plan for a deep water rig.
