Page 74 - Well Control for Completions and Interventions

P. 74

CHAPTER TWO

Well Construction and
Completion Design

Well control during completions, workover, and interventions requires a
broad understanding of how the well is constructed, familiarity with dif-
ferent completion designs, and a good understanding of wellhead and
downhole completion equipment. Armed with this knowledge, those
planning and executing completion and intervention activities will be
able to identify potential leak paths, and maintain an increased level of
vigilance during operations where the risk of loss of containment is
increased. A good understanding of the well construction process and
completion architecture will also enable rig site personnel to respond
more effectively in the event of a well control incident.
This chapter of the book describes the well construction process (dril-
ling and casing the well) before going on to discuss completions and
completion design.

2.1 WELL CONSTRUCTION

Nearly all wells are constructed using a series of casing strings,
where each string reduces (tapers down) in diameter as the well gets dee-
per. Each casing is cemented in place, bonding it to the borehole. A
properly cemented casing string will prevent formation pressure migrating
to the surface, provide isolation between layers in the formation, support
the borehole, and strengthen the casing. A series of tapered and cemented
pipes is a construction concept that will be instantly recognized by anyone
who has worked in the upstream side of the oil industry for any time.
Casing design is normally the remit of the drilling engineer, who will
strive to find a design that allows the well to be drilled safely and eco-
nomically, whilst at the same time resisting the many forces that are a nec-
essary part of the drilling process. Casing should be designed to maintain
integrity throughout the life of the well.

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