Page 9 - A Primer of Oilwell Service and Workover Completion
P. 9
WELL COMPLETION
Petroleum Extension-The University of Texas at Austin
WELL COMPLETION
fter a drilling crew has CASING
A drilled a hole to the reservoir CONDUCTOR
CASING
and lined the hole with pipe, Let’s begin by reviewing the
pipe, or casing, that lines the
it may or may not do the addi-
hole from the start of drilling
tional work needed to get the
to the end. Threaded couplings
well into production. Sometimes
connect each joint of casing to
crewmembers move on to drill
form a casing string, which is the
another well, and a well servicing SURFACE
crew comes in to add the equip- entire length of the casing. CASING
A cementing crew cements a
ment needed to start the hydro-
string of casing in the hole as it
carbons flowing, or to complete
is drilled; there fore, casing is not
the well.
Completion begins with easily removable.
During drilling and com-
install ing tubing inside the INTERMEDIATE
casing to provide a flow path for pletion, the crew runs several CASING
strings of casing into the hole.
oil and gas. The completion crew
sets a seal called a packer to seal Each casing string fits inside the
last, so each string is smaller in
off the space between the tubing
diameter than the one set before PRODUCTION
and the casing and installs a well-
it (fig. .). The first string is CASING
head to control the flow of the
the conductor casing, a relatively
reservoir fluids. Finally, the crew RESERVOIR
short string ( to feet, or
may install equipment such as a
to metres) of large-diameter
pump to lift oil to the surface, if CEMENT
pipe that keeps the top part of
natural drives cannot force it up. CASING
the hole from caving in during SHOE
drilling. The crew then drills
below the conductor casing to Figure .. Concentric strings of
just past the depth of the deep-
casing line the drilled hole.
est fresh water in the formation.
