Page 137 - Well Control for Completions and Interventions

Completion Equipment 129

Figure 3.34 A SC-SSSV shown in the open and closed position. Image courtesy of
Jonathan Bellarby

The tubing retrievable valve (TR SC-SSSV) has four significant
advantages over the wireline retrievable (WR SC-SSSV) valve.
• Improved reliability.
• Improved integrity—the valve is an integral part of the completion
string.
• Large through bore. The pressure drop and turbulent flow cased by
the restricted ID of wireline set valves can lead to the formation of
scale, compromising the valves integrity.
• No requirement to pull the valve for through tubing interventions.
Tubing retrievable valves have become the valve of choice for subsea
completions, intelligent completions, and completions in locations where
interventions are complex, time consuming, or expensive. A wireline
retrievable valve functions in the same way as a tubing retrievable valve.
Internally, the valve configuration of piston, flow tube, spring, and closure
mechanism is the same. The only real difference is the method of deliver-
ing control fluid to the piston. In the tubing retrievable valve, the control
line is connected directly to the hydraulic chamber. In wireline