12
In operation, the Overshot functions in the same manner, whether dressed
with Spiral Grapple parts or Basket Grapple parts.
During the engaging operation, as the Overshot is rotated to the right
and lowered, the Grapple will expand when the fish is engaged, allowing the fish
to enter the Grapple. Thereafter, with rotation ceased and upward pull exerted,
the Grapple is contacted by the tapers in the Bowl and its deep wickers grip the
fish firmly.
During the releasing operation, a sharp downward bump places the
larger portion of the Bowl tapers opposite the Grapple, breaking the hold.
Thereafter, when the Overshot is rotated to the right and slowly elevated, the
wickers will screw the Grapple off the fish, effecting release.
The fact that Bowen Releasing and Circulating Overshots require
right-hand rotation only, both during engaging and releasing
operation, is extremely important. This feature eliminates the dangers that
are present when it is necessary to rotate the string in an unscrewing direction.
Pack-Off Mechanism
The type of Pack-off used depends on how the Overshot is dressed and the
operators’ choice.
When the Overshot is dressed with a Spiral Grapple a Type “A” Packer is used.
The Type “A” Packer is a sleeve type. It seals at its O.D. against the inside
of the Bowl. It has an internal lip which seals around the fish. Each Type “A”
Packer is designed to packoff a specific size. A Type “A” Packer should be
ordered for each catch size Spiral Grapple.
Control Packers are used when the Overshot is dressed with a Basket
Grapple. Control Packers are standard with a Type ‘R” (Replaceable) Packer.
The patented Double Lip Packer provides greater sealing ability and reduces the
chance of seal damage during fish engagement. The outer seal is also replace-
able, this allows for field replacement of either seal. The control is also provided
in a Mill type designs. The Plain Control Packer is used when the milling
operation has already been performed prior to the fishing operation. The Mill
Control Packer is used when light dressing is required prior to fish engagement.
NOTE: Only one control can be installed in the overshot assembly at a time! Control
Packers are manufactured for a specific size. One should be ordered to match
each basket grapple size that has been ordered.
Plain Controls are used when no packoff is required. They are installed in
the same location as the Control Packer.
NOTE: The tables on the following pages list all available controls. Refer to those
tables for the proper part number.
Operation:
Engaging and Pulling the Fish
Connect the Overshot to the fishing string and run it in the hole. As the top
of the fish is reached, slowly rotate the fishing string to the right and gradually
lower the Overshot over the fish. Allow the right-hand torque to slack out of
the fishing string, and pull on the fish by elevating the fishing string. If the fish
does not come, start the circulating pumps and maintain a heavy upward strain
while fluid is forced through the fish.
Releasing From the Fish
Drop the weight of the fishing string heavily against the Overshot, then
simultaneously rotate to the right and slowly elevate the fishing string until the
Overshot is clear of the fish.
To release from a recovered fish, follow the same procedure while holding
fish below the Overshot.
Overshot Accessories
The more commonly used accessories for Bowen Series 150 Overshots are
Extension Subs, Oversize Guides, Wall Hook Guides, Milling Shoes, and Lock
Rings. These accessories are illustrated and listed beginning on page 20.
Calculated strength data on all Bowen Series 150 Overshots is listed in brochure
BR-110. Copies are available on request.
Send for Bowen Technical Manual No. 1150 which includes complete descriptions
of construction, operation, maintenance, and parts listing for Bowen Series 150
Releasing and Circulating Overshots.
Bowen Series 150 Releasing
and Circulating Overshot
With Basket Grapple
Packer
Spiral Grapple
Top Sub
Type A Packer
Bowl
Spiral Grapple
Guide
Grapple Control
Spiral Grapple
Control
Bowen Series 150 Releasing
and Circulating Overshots