|3D KEY SEAT WIPER|
You may not be able to prevent key seats
in dog-legs and deviated holes, but you
can prevent costly stuck strings...
While drilling, the rotary action of the drill pipe often forms key seats in the hump of the dog-legs in the low or high side of deviated holes.
When tripping out, the larger OD. of the drill collar can wedge in the narrow groove of the key seat - necessitating expensive recovery operations.Operation
The 3D Key Seat Wiper is made-up just above the top drill collar. It contains a sliding reamer sleeve with an O.D. slightly larger than the collar. When coming out of the hole, this sleeve detects the key seat first - instead of the drill collar - by becoming wedged in restricted space.
By releasing the drill pipe, the sleeve may be jarred out of the key seat. A clutch-drive on the bottom of the sleeve and the lower body is engaged by right-hand rotation.
Slowly raising the string and continuing rotation allows the sleeve to function as a reamer and wipe out the key seat. The operation may be repeated to further enlarge the area, thus permitting free passage of the collars.
Spiral blades with tungsten carbide hard-facing provide fast cutting action and maximum resistance to wear.