Pipe string handling apparatus and method

Details Pipe string handling apparatus and method Pipe string handling apparatus and method

1999-06-11

2001-05-29

Bagnell, David (Department: 3672)

Wells

Above ground apparatus

With means facilitating connecting or disconnecting...

C166S075140

Reexamination Certificate

active

06237684

ABSTRACT:

This invention pertains to apparatus and methods for handling pipe strings extending generally downward from drilling and production platforms. More specifically, it pertains to the use of apparatus to engage the shoulder of the pipe string connector such that an elevator and support table can individually support the pipe string load while sharing the downwardly facing load bearing area, or areas, of the pipe load supporting connector.
BACKGROUND
Since the rotary drilling system has been in use it has been commonplace to use a first elevator as a temporary substitute for a spider to support a tubular well string while a second elevator, supported by the bails of the traveling block, engages the lower shoulder of the top connector of a tubular joint being added to the string. When the last added pipe section is safely secured to the string, the top elevator then lifts the string to allow the first elevator to be slid aside. The string is then lowered by the second elevator until it engages the rig floor level support which is usually a landing table or rotary table cover plate. The traveling block bails are then removed from the second elevator and attached to the first elevator, by which a new pipe section is accessed, and the process is repeated. This is referred to as “circulating the elevators”. The procedure is reversed to remove a tubular string from the well.
Several different pipe handling procedures have been developed to alter the handling procedure defined above but no single best way has evolved.
The process described above has naturally evolved to satisfy the need to handle risers approaching a platform from the sea bed below. Risers can usually afford connectors of larger outside diameter, compared with well string tubing, and there is usually enough surface to accept the loads, and contact areas, of both elevator and support table if the load transmitting elements are arranged for that purpose.
In some cases, the pipe string outer surfaces are very sensitive to surface damage. That sensitivity usually results from metal, surface, and heat treatment selection to best accept local chemical conditions. Each type of connection, however, can be supplied with a sleeve with mating surfaces that minimize localized stresses when lifting the string by surfaces the sleeve makes available.
It is desirable and an object of this invention to provide apparatus and methods to avoid the repeated disconnecting of the bails to circulate the elevators.
It is another object to simplify the nature, use, and cost of structure to serve the simple support function of the spider, and allow the novel support table and elevator to simultaneously engage the lifting areas of the string components.
It is still another object of the invention to provide a temporary sleeve to safely engage complex surfaces of the pipe and connector and to provide more usable surface, or surfaces, to engage the support table and elevator simultaneously to change support for the string to and from the elevator.
These and other objects, advantages, and features of this invention will be apparent to those skilled in the art from a consideration of this specification, including the attached claims and appended drawings.
SUMMARY OF INVENTION
The present invention utilizes a support table with an upwardly protruding tubular neck to support the suspended pipe string. The neck clears the elevator lower ledge and extends upward through the elevator bore to engage downwardly facing surfaces of the upper connector of the string. If the elevator has no lower ledge, one is provided in the form of a split tubular liner with an outwardly extending upper ledge and an inwardly extending lower ledge. The upper ledge engages the load lifting surface on the elevator and the lower ledge engages the downwardly facing load bearing area of the connector or a lower shoulder, or face, of a temporary lift sleeve. The split liner is, preferably, secured to the elevators such that it needs no opening hinges. If the downwardly facing load bearing surface of the connector has enough radial dimension, the support table may engage about half the shoulder area and the elevator can engage the outer half of that surface when shifting string load between support table and hook. The downwardly facing load bearing surface of the connector can be located at different axial levels, or stepped.
If the connector shoulder does not have enough bearing surface, or is tapered or rounded, a temporary lift sleeve is added below the connector to suitably engage available and usable surfaces on the string and provide substitute load bearing surfaces for lifting the string. The lift sleeve is short axially and has downwardly facing surfaces large enough to accept both the pipe string and the elevator. Both lift sleeve and support table are split to be opened to accept lateral movement of the string into their general centerlines. Either, or both, support table and lift sleeve can be hinged to admit pipe but either can be confined about the pipe by other means. Laterally sliding load bearing plates can be used with the support table. The support table can be handled well if each part of the split support table is attached to a laterally movable loading plate that rests on the rotary table cover plate or other structure. Sometimes a shock table that has a gas cushion bears the load of the support table.
The methods disclosed herein are designed to optimally use the novel apparatus elements of this invention.


REFERENCES:
patent: 2689139 (1954-09-01), Jones et al.
patent: 3094852 (1963-06-01), Taylor
patent: 4697830 (1987-10-01), Wood et al.
patent: 5755289 (1998-05-01), Angman et al.

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