The kelly valve , which is a manually operated ball valve in the drill string , is one of effective tool for preventation from blowout . The kelly valve is divided into upper kelly valve and lower kelly valve. The upper kelly valve is connected between lower end of swivel and upper end of kelly . The lower kelly valve is connected between upper end of drillpipe and lower end of kelly or connected between lower end of kelly saver subs. The kelly valve features a simple operation, the kelly valve can be opened on or closed off by only turning the special operating spanner at 90 degrees according to indicating direction . During drilling operation, in order to avoid serious well kick or blowout accident , the kelly valve shall be connected at upper end and lower end of kelly.
Technical parameters and specifications for the upper kelly valve
| Type |
O.D.(mm) |
Thread connection
(API) |
I.D.(mm) |
Max.Sealing Pressure
Mpa |
| CS146 |
146 |
4 1/2REG LH |
50 |
35;70;105 |
| CS200 |
200 |
6 5/8REG LH |
75 |
Technical parameters and specifications for the lower kelly valve
| Type |
O.D.(mm) |
Thread connection
(API) |
I.D.(mm) |
Max.Sealing Pressure
Mpa |
| XS105 |
105 |
NC31 |
40 |
35;70;105 |
| XS121 |
121 |
NC38 |
50 |
| XS127 |
127 |
NC38 |
50 |
| XS165(168) |
165(168) |
NC50 |
70 |
| XS178 |
178 |
NC50 51/2FH |
70 | |
