Well Integrity and Well Control

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,

  • Development of automated kick-detection systems (one of the papers summarized here addresses kick detection during connections)
  • Kick detection just above the bit using logging-while-drilling information
  • Kick detection using wired drillstring
  • Research on the effect on kick detection of gas solubility in nonaqueous drilling fluids (mineral oil, paraffin, ester, and olefins)
  • The use of managed-pressure-drilling systems (one of the papers recommended for additional reading comments on the advantage of this technology in reducing the kick size)

Recommended Additional Reading

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.


Otto Luiz Alcantara Santos, SPE, is an independent consultant and instructor of well-control and advanced well-construction technologies. During almost 40 years, he worked as a Petrobras well-construction engineer. Santos holds a BS degree in civil engineering and an MS degree in petroleum engineering from the Colorado School of Mines and a PhD degree in petroleum engineering from Louisiana State University. He was also a faculty member at the University of Tulsa in 1994. Santos has written several technical papers in well-construction technology, especially on well integrity and directional and horizontal drilling. He is the author of the book Well Control in Drilling Operations and coauthored the book Directional Drilling. Santos is editor of the SPE book Drilling and Production Operations in HPHT Wells. He was an SPE Distinguished Lecturer for 2009–2010. Santos is the current program chairperson of the SPE Bahia/Sergipe Section and has served or is currently serving on several SPE committees. He is also a member of the JPT Editorial Committee. In 2010, Santos received the International Association of Drilling Contractors Exemplary Service Award. He can be reached at ottolasantos@gmail.com.

Well Integrity and Well Control

Otto Luiz Alcantara Santos, SPE, Consultant

20 December 2016

Volume: 69 | Issue: 1

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