Page 79 - Well Control for Completions and Interventions

70 Well Control for Completions and Interventions

Figure 2.3 Open hole barefoot completion.

Table 2.1 Open hole completions summary
Advantages Disadvantages
No casing and perforating costs Water or gas entry difficult to control
Saves rig time Not easy to selectively stimulate different
parts of the producing interval
Easy to deepen or side-track if Open hole section subject to collapse—
desired may require frequent clean-out
Can be converted to screen or liner Only applicable to well consolidated
completion at a later date formation
Large inflow area—high rate Drilling damage can be difficult to remove
production and can lead to reduced inflow

Predrilled and slotted liners are not normally used for sand control; it
is difficult to cut slots fine enough to hold back the sand pack. Where
very small slots are used (laser cut) the flow area is small, and they become
susceptible to plugging. Predrilled liners are generally preferred because
of better inflow performance; they are also cheaper to manufacture.
Predrilled and slotted liners can be deployed with washpipe if there
are concerns about reaching bottom. In many cases, the liners are run
with mud still in the hole. This reduces the risk of surge and swab
induced kicks or losses (Figs. 2.4 and 2.5; Table 2.2).