Well Control for Offshore High-Pressure/High-Temperature Highly Deviated Gas Wells Drilling: How to Determine the Kick Tolerance?

Kick tolerance is a vital parameter for well control. It indicates if a shut-in operation can be performed or not, an appropriate method of well killing should be selected. However, the kick tolerance determination for offshore high-pressure/high-temperature (HP/HT) highly deviated gas wells drilling still remains as a challenge to the oil and gas industry due to the presence of narrow safe mud weight window of the HP/HT well section, complex borehole temperature profile, influx distribution and high frictional pressure loss. In this work, a model of volume kick tolerance specific for offshore HP/HT highly deviated gas wells drilling was presented based on the pressure bearing capacity of highly deviated open hole, casing shoe, casing, blowout preventer (BOP) and choke valve. Meanwhile factors affecting the volume kick tolerance were also investigated. The result shows that both of the volume kick tolerance for shut-in and the volume kick tolerance of well killing increase with wellbore inclination of the highly deviated section, and the highly deviated wellbore or highly deviated wellbore may have a much higher volume kick tolerance than that in vertical wellbore. With other parameters values setting constant in this case, the volume kick tolerance of well killing increases with the geothermal gradient while the increase rate is not obvious. This work provides a practical tool for enhancing well control in offshore HP/HT highly deviated gas wells drilling.