Pipe guide for snubbing units

Abstract

A pipe guide apparatus for guiding a pipe during snubbing of the pipe includes a pair of hydraulic cylinders and cylinder rods; a stationary guide affixed between a bottom jack plate and a top jack plate, comprising a stationary pipe guide; a travelling jack plate affixed to the cylinder rods; a travelling pipe guide in sliding engagement with the cylinder rods and connected to the travelling jack plate by a lift rod. The stationary pipe guide and the travelling pipe guide each define a pipe opening and has a flexibly resilient guide member having an opening with a diameter closely matching the outside diameter of the pipe being snubbed.

Description

FIELD OF THE INVENTION[0001]The present invention relates to pipe guides for use in snubbing units for snubbing pipes into and from oil and gas wells.BACKGROUND OF THE INVENTION[0002]Snubbing units are used to feed pipes into and out of subterranean wells. A conventional snubbing unit includes stationary snubbing slips or grippers and traveling snubbing slips to alternately grip and release a pipe as the traveling snubbing slips are moved towards and away from the stationary snubbing slips.[0003]Traditional pipe guides on snubbing units used today typically employ two interlocking and telescoping tubes positioned between the stationary snubbing slips and the traveling snubbing slips. Inherent problems with these pipe guides include the space and weight of the pipe guidance systems and the heights which they add to the snubbing units. Also, approximately one half of the effective stroke of the snubbing unit is lost and snubbing operations therefore become much less efficient than wou...

AI Technical Summary

Problems solved by technology

Inherent problems with these pipe guides include the space and weight of the pipe guidance systems and the heights which they add to the snubbing units.

Also, approximately one half of the effective stroke of the snubbing unit is lost and snubbing operations therefore become much less efficient than would be the case if full snubbing strokes could be taken.

A pipe that is being snubbed into or out of a live well can only support a limited amount of compressive force before the pipe buckles.

Once these calculations have been made, a snubbing operator uses short strokes to move the pipe into or out of the well, never allowing more unsupported exposure than calculated.

With a rig assist-snubbing unit, however, the overall height is critical because the snubbing unit must work within the height restraint of the top of a derrick forming part of a rig in conjunction with which the snubbing unit is being operated.

The distance between the top of the snubbing unit and the inside working area from the top of the rig derrick in many cases eliminates the option of having pipe guidance apparatus, because the additional height that the apparatus would add to the snubbing unit would not allow sufficient space for lengths of pipe to be handled.

Consequently, the operators have resorted to performing the dangerous short stroking operation on high-pressure wells, as described above.

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