As a well-control instructor and researcher for the past 20 years, I am often surprised that some in our industry have the opinion that well control begins with the occurrence of a kick and ends when the kick has been killed, when in reality, well control begins when the well location is selected. Every decision after this point must consider controlling formation pressures to prevent any unintended influx into the wellbore, buildup of annulus pressure, and uncontrolled flow of wellbore and formation fluids during the drilling, completion, and production operations and even after the well is plugged and abandoned. Serious well-control incidents can occur any time after the well is spud in, even when least expected.
Two recent incidents in the Gulf of Mexico remind us of this fact. The first that I will mention is the BP Macondo blowout. Because this incident has been covered thoroughly by the media, all I will say is, Could part of the reason for loss of control be that the crew thought that just because casing had been set and cemented that nothing could happen and then when it did, it caught them off guard? This example is a vivid reminder that once casing is installed and cement is pumped, the danger is not over.
The other incident never made the news because there was nothing spectacular about itno injuries, no explosion, and no release of oil into the Gulf. This incident was mentioned briefly at the 2010 Decommissioning Summit, Gulf of Mexico. I bring it up to point out that, even though the industry as a whole exceeds mandated plugging requirements, things still can go wrong. As was stressed at the summit, industry needs to think of plugging as a business, not just an expense at the end of the life of the well. After all, we intend for the plugs to last for eternity.
Well Control additional reading available at OnePetro: www.onepetro.org
SPE 130693 Snubbing Units Used Effectively in Well-Control-Recovery Efforts by S.R. Wehrenberg, SPE, Boots & Coots, et al.
SPE 133027 Key-Factor Sensitivity Analysis on Blowout Probability in Dangerous Drilling ConditionsApplying Different Technical Solutions by S. Masi, Eni E&P, et al.
SPE 131332 Drilling Through Gas-Hydrate Sediments: Managing Wellbore-Stability Risks by T. Khabibullin, SPE, Texas A&M University, et al.