One of the more important aspects of well integrity during drilling operations is early kick detection. When an unintentional flow of the formation fluid into the wellbore occurs during conventional drilling operations, it must be detected promptly and the flow must be stopped, normally by closing the well. The early detection is crucial in minimizing the influx size. When the amount of formation fluid inside the well is large, especially if it is gas, the pressure inside the well will be higher during the subsequent well-control operations. This can lead to an increase in time to control the well or even to a worse situation: the loss of control. Another concern may be the amount of formation fluid to be handled at surface. Deepwater, high-pressure/high-temperature, and slimhole drilling are situations where early kick detection is mandatory.
The early kick detection is accomplished with a rig equipped with the appropriate kick-detection sensors and alarms and with a rig crew trained in quickly recognizing a kick and in the shut-in procedures. However, there are situations where early kick detection becomes more problematic—for example, when operating on a floating rig because of its motions, when using nonaqueous drilling fluids because of gas solubility, or during connections.
Recently, new technologies and re-search have been applied or developed to improve the kick-detection systems and to overcome some of the difficulties. To cite just a few examples,
SPE/IADC 173153 A Barrier-Analysis Approach to Well-Control Techniques by D. Fraser, Argonne National Laboratory, et al.
SPE 180047 Impact of New and Ultrahigh-Density Kill Fluids on Challenging Well-Kill Operations by T. Rinde, Acona Flow Technology, et al.
SPE 180053 A Numerical Study of Gas-Kick Migration Velocities and Uncertainty by K.K. Fjelde, University of Stavanger, et al.
Well Integrity and Well Control
Otto Luiz Alcantara Santos, SPE, Consultant
01 January 2017