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 |