Page 112 - Well Control for Completions and Interventions

104 Well Control for Completions and Interventions

Figure 3.14 Premium threaded and coupled connection.

3.4 PRODUCTION LINERS

A liner can be defined as a casing string that does not extend back
to the wellhead. Instead it is set (hung off) above the shoe of the previous
casing string. Liners are used for drilling purposes and as production liners.
Drilling liners are used to extend intermediate casing through troublesome
zones where further drilling is planned. Many subsea wells use drilling
liners, because of the limited number of casing strings that can be installed
in a subsea wellhead. Production liners are set across the reservoir, and are
an integral part of the lower (sand-face) completion. Since they are
exposed to flow, they must be compatible with produced (and injected)
fluids and robust enough to withstand any additional stress from produc-
tion enhancement operations, for example, reservoir stimulation. Liners
are normally cemented in place, usually along their entire length. Slotted
and predrilled liners are not cemented, although increasingly swell packers
and open hole packers are used for conformance (zonal isolation)
purposes.