Page 7 - Well Control for Completions and Interventions

2 Well Control for Completions and Interventions

Table 1.1 Operational phase during blowouts a
Number of well control incidents by activity and area: 1960 96
Operational phase Texas Offshore Continental
Shelf (United States)
Exploration drilling 244 45
Development drilling 180 49
Other drilling 14 4
Completion 64 25
Workover 197 23
Wireline 19 5
Production 85 12
Missing data 15 23
Total 817 186
a
Trends extracted from 1200 Gulf Coast blowouts during 1960 96. Pal Skalle (NTNU, Trondheim,
Norway) A.L. Podio, (University of Texas). World Oil, June 1998.

• Completions and workovers are normally carried out with clear, solids
free, fluid in the well. The risk of fluid losses is greater than when
using mud.
• Interventions are routinely performed with the well live (pressure at
surface). Any failure of the pressure control equipment results in an
immediate release of hydrocarbons.
Each of these risks can be managed if the crew is experienced and
well-trained. However, for many years the only well control training
available (and recognized by the industry) was drilling well control.
Candidates were (and still are) taught how to recognize a kick, how to
shut in the well, and then how circulate out the kick with weighted up
mud. Whilst this is a vital skill for anyone working as a member of a drill
crew, it ignored many of the well control complexities than can arise
during a completion or workover.
In today’s oilfield, there is much more emphasis on workover and inter-
vention well control training. However, many would argue that there is still
a bias towards drilling. The aim of this book is to redress the balance and
provide the reader with a better understanding of well control problems that
can arise when completing, working over, or intervening in wells.

1.1.1 Workover or intervention?
Well intervention, completion, and workover are common industry
terms. Whilst the term completion is generally unambiguous, the terms