Page 83 - Well Control for Completions and Interventions

74 Well Control for Completions and Interventions

Table 2.4 Sand control completions summary
Advantages Disadvantages

Sand production eliminated or Costly
significantly reduced
Difficult to install
Risk of high skin and increasing skin over time
with many gravel pack/frac pack completions
Poor record of reliability—mean time to failure
for screen-only completions is 7 years
Zonal isolation, water and gas shut-off difficult
in open hole sand control completions
Screen failure normally means extensive length
and costly workover. Side track normally
needed

completion (production tubing) can be installed. Screens can be run with
(highly conditioned) mud still on the well, and the mud flowed back
through the screens and gravel (if used). Some operators displace the mud
from the well, replacing it with clear filtered brine, before the screens are
run. There is a risk from losses unless a properly formulated lost circula-
tion material is used. The LCM must be sized to prevent losses, but still
enable flow-back through the screens (and gravel). There are well control
problems particular to the running of screens, and these are described
fully in Chapter 7, Well Kill, (Table 2.4).

2.2.6 The upper completion
The upper completion is the conduit taking the hydrocarbons from the
lower (reservoir) completion to the surface. A number factors will influ-
ence the configuration of the upper completion. These will include:
• Pressure isolation requirements between reservoir and surface—is a
packer required?
• Integrity requirements—Surface Controlled Sub Surface Safety Valve
(SC-SSSV) and Annulus Safety Valve (ASV).
• Reservoir management requirements—single string multizone com-
pletion or dual string completion.
• Tubing size (driven by production potential and expected decline).
• Artificial lift requirement.
• Life of field concerns.
• Intervention requirements.