A mathematical model was developed to predict the pressure variation in the choke line and the annular region of the well during a well control situation that takes place after a kick occurrence while drilling. The results showed that, in deep waters, the kick could be circulated out of the well at usual killing pump rates and that in most cases it is needles to use the cement pump (for lower ... [Show full abstract] kill rates) but that a quick check can be done using the procedure outlined in the paper.
Ilfrey et al. was one of the first to study the problem of well control in deep waters in which he investigated the surface casing pressure variation while using the "driller's method" to circulate the kick out of the well. In his studies he modeled the kick as a single slug and neglected the friction losses while circulating. His approach overestimated significantly the casing pressure variation when the gas began entering the choke line at the usual circulating kill rate of 30 or 40 strokes per minute (spm). Therefore that study led toward the use of the cementing pump, before the gas entered the choke line, that enabled flow rates of 0.5 to 2.0 bbl/min(1.310(-3) -5.310(-3)m3/s respectively) thus providing enough time to operate the choke appropriately. Due to the conservative nature of those predictions that method is still used by some drilling engineers. The present study modeled the pressure behavior of the two phase region, that occurs during a kick while drilling, to phase region, that occurs during a kick while drilling, to predict the casing shoe and the casing surface pressure profiles, predict the casing shoe and the casing surface pressure profiles, while circulating out the kick, and their respective variations with regards to time (for a given pump flow rate) to deterReferences and illustrations at end of paper. mine the best pump rates for efficient well control operations in deep waters.