ISO 28781 and API Spec 19V are international standards that prescribe the requirements for subsurface barrier valves and related equipment for use in the petroleum and natural gas industries. Subsurface barrier valves provide a means of isolating the formation or creating a barrier in the tubular to facilitate the performance of well operations before production or injection starts. Barrier valves are also available for the postproduction or postinjection phase.
The standards define
| Validation Grade | Test Medium | Flow Rate At | ||
|---|---|---|---|---|
| Validation Grade |
Test Medium |
Flow Rate At 200 psi Across Barrier | Flow Rate At 50% Rating | Flow Rate At 100% Rating |
| Validation Grade V1 | Test Medium Liquid | Flow Rate At 10 mL/min | Flow Rate At 5 mL/min | Flow Rate At 5 mL/min |
| Validation Grade V1 | Test Medium Gas | Flow Rate At 1 ft3/min | Flow Rate At 0.5 ft3/min | Flow Rate At 0.5 ft3/min |
| Validation Grade V2 | Test Medium Liquid | Flow Rate At 30 mL/min | Flow Rate At 15 mL/min | Flow Rate At 15 mL/min |
| Validation Grade V2 | Test Medium Gas | Flow Rate At, Flow Rate At, Flow Rate At No requirement | ||
| Validation Grade V3 | Test Medium, Flow Rate At, Flow Rate At, Flow Rate At Supplier- or manufacturer-defined and successful field history of 20 similar valves | |||
| Barrier from Above | Barrier from Below | Barrier from Above and Below | |
|---|---|---|---|
| Preproduction and preinjection barrier valves | Barrier from Above Type A | Barrier from Below Type B | Barrier from Above and Below Type C |
| Postproduction and postinjection barrier valves | Barrier from Above Type AA | Barrier from Below Type BB | Barrier from Above and Below Type CC |
