Failure Mode

Effect

Safeguards

Criticality

Fail to close on demand (FTC)

Totally loss of primary barrier, increase the well leak probability.

Periodic function test of DHSV.

High

Leakage in closed position (LCP)

If the leakage in within criteria, no significant consequence, otherwise the barrier element is considered degraded or failed.

Periodic pressure test of DHSV.

Medium

Premature valve closure (PCL)

Lead to well shut-in unplanned, loss of production.

Low

Fail to open on command (FTO)

Loss of production.

Low

Control line to well communication (CLW)

Loss of hydraulic pressure leading to DHSV closed. Loss of production.

Low

Well to control line communication (WCL)

Since the pressure in the A annulus is higher than the control line, therefore the DHSV will fail to close in case of WCL.

Periodic pressure test of control lines.

High