A blowout preventer (BOP) is a specialized valve or similar mechanical device, used to seal, control and monitor oil and gas wells to prevent blowouts, the uncontrolled release of crude oil or natural gas from a well. They are usually installed in stacks of other valves.
Well Kicks can lead to a potentially catastrophic event known as a blowout. In addition to controlling the downhole (occurring in the drilled hole) pressure and the flow of oil and gas, blowout preventers are intended to prevent tubing (e.g. drill pipe and well casing), tools, and drilling fluid from being blown out of the wellbore (also known as bore hole, the hole leading to the reservoir) when a blowout threatens. Blowout preventers are critical to the safety of crew, rig (the equipment system used to drill a wellbore) and environment, and to the monitoring and maintenance of well integrity; thus blowout preventers are intended to provide fail-safety to the systems that include them.
FZ Type Ram blowout preventer (BOP)with manual locking operators provides a rugged and reliable preventer that is easily serviced in the field. Special features include:
- The BOP is designed and manufactured according to specifications API Spec 16A.
- The part in the BOP, in contact with liquid in well is resistant to hydrogen sulfide
stress corrosion, and the requirements of NACE MR-0175 are met.
- The BOP is hydraulically closed and manually locked by rotating the locking screw.
- The door is supported by hinge bracket and rotary opened.
- Special surface treatment is applied to key components such as ram shaft and
locking shaft to prevent it from corrosion and wear
The FZ ram BOP is an integral part of well control equipment and is mainly employed to control wellhead pressure in the process of drilling, workover, testing etc. in order to prevent occurrence of the well blowout and realize safety construction. It can be applied to complete the following work:
- In the case of the pipes in the well, when equipped with the corresponding pipe ram,
it can be used to seal off the annular space between the casing and the pipes.
- In the case of no pipes in the well, when equipped with blind ram, it can be used to
seal off the wellhead completely.
- While enclosing the well, mud circulating, pressure releasing, well killing and well
cleaning can be performed by means of the spool and the choke manifold connected
to the outlet at the side of BOP body.
- When ram BOP is used together with the choke manifold and kill manifold, it can
effectively control the bottom hole pressure and achieve near-balanced drilling
operation.
Ram BOP consists of some main parts such as body, doors, cylinders, pistons, ram shafts, locking shafts, cylinder heads, and ram assemblies etc. Main pressure-containing parts such as body and side door are cast with high-quality alloy steel, the material conform to NACE MR-01-75 specification, apply to the working condition of acid medium and specially heat treatment. The pressure-containing parts has do the hydrostatic test in accordance to the specification of API 16A to ensure safety during
operating under working pressure.
There are high supporting ribs at the bottom and sides of the ram cavity of the body, correcting the ram location automatically when closing the ram. There are oblique plane for settling and sloping to the well hole at the bottom of the ram cavity, de-sanding automatically when opening and closing the ram, prevent blocking and reducing friction of the ram. It is also helpful for well pressure assisting ram seal.
Table 1
| Description |
Single Ram |
Double Ram |
Single Ram |
Double Ram |
| BOP |
BOP |
BOP |
BOP |
| Model |
FZ18-21 |
2FZ18-21 |
FZ18-35 |
2FZ18-35 |
| Performance Level |
PR1 |
| Bore |
179.4mm(7 1/16 in) |
179.4mm(7 1/16 in) |
| Rated Working Pressure |
21MPa(3000psi) |
35Mpa(5000psi) |
| Body test pressure |
31.5MPa (4500psi) |
52.5MPa(7500psi) |
| (Factory Test Only) |
| Hydraulic-control rated |
21 MPa(3000psi) |
| working pressure |
| Recommended |
8.4-10 .5MPa(1200-1500psi) |
| hydraulic-control |
| operation pressure |
| Opening Volume |
2 L×2 |
2 L×4 |
2 L×2 |
2 L×4 |
| Closing Volume |
2.4 L×2 |
2.4 L×4 |
2.4 L×2 |
2.4 L×4 |
| Temperature Rating |
T-20/250 |
| Closing Ratio |
4.6 |
4.6 |
| Locking Screw turns |
18 |
18 |
| (each end) |
| Weights |
1075kg |
1950kg |
1115kg |
2008kg |
| Center of gravity |
348 |
497 |
366 |
498 |
Table 2
| Description |
Single Ram |
Double Ram |
Single Ram |
Double Ram |
| BOP |
BOP |
BOP |
BOP |
| Model |
FZ28-21 |
2FZ28-21 |
FZ28-35 |
2FZ28-35 |
| Performance Level |
PR1 |
| Bore |
279.4mm(11 in) |
279.4mm(11 in) |
| Rated Working Pressure |
21MPa(3000psi) |
34.5Mpa(5000psi) |
| Body test pressure |
31.5MPa (4500psi) |
51.7MPa(7500psi) |
| (Factory Test Only) |
| Hydraulic-control rated |
21 MPa(3000psi) |
| working pressure |
| Recommended |
8.4-10 .5MPa(1200-1500psi) |
| hydraulic-control |
| operation pressure |
| Opening Volume |
2.7L×2 |
2.7L×4 |
5.2 L×2 |
5.2 L×4 |
| Closing Volume |
3.3L×2 |
3.3L×4 |
5.9 L×2 |
5.9 L×4 |
| Temperature Rating |
T-20/250 |
| Closing Ratio |
4.5 |
5.6 |
| Locking Screw turns |
23.5 |
26 |
| (each end) |
| Weights |
1460kg |
2805kg |
2890kg |
5280kg |
| Center of gravity |
315 |
500 |
424 |
615 |
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