TOOL FOR CONNECTING AND DISCONNECTING TUBULARS

This invention regards a tool for connecting and disconnecting tubulars . More particularly it regards a tool for connecting or disconnecting tubulars near a drill floor, the tool comprising a power tong and a backup tong, wherein the tool is located at the same level as or below the drill floor.

To speed up the running of a pipe string into or out of a wellbore, several pipe stands are often joined to form stands which can be placed in intermediate storage until such time as it is to be used. Similarly, stands are split up as they are pulled out of a wellbore.

A drill floor is typically provided with an opening, a so- called "mousehole", leading to a mousehole machine below, in which a pipe/tubular or a pipe stand is placed for connection to or disconnection from a pipe section.

According to prior art, a mechanized pipe tong is used for the actual connection and disconnection (making and breaking

operations) . A mechanized pipe tong of the type in question comprises a device that runs on rails or is otherwise displaceable, arranged to be moved along the drill floor up to the mousehole, and then back to an idle position when the tubulars have been connected or disconnected. The mechanized pipe tong by the mousehole occupies a relatively large part of the drill floor, which has to accommodate a lot of equipment required for the numerous operations carried out from the drill floor. Thus the fact that the power tong for connecting and disconnecting pipe stands also occupies floor space on the drill floor is a considerable drawback.

US publication 6 212 967 concerns a tong construction located on the drill floor, but which is arranged to cooperate with a spinner unit in or below the drill floor. However, the tong construction still occupies some floor space.

The object of the invention is to remedy or reduce at least one of the drawbacks? of prior art.

The object is achieved in accordance with the invention, by the characteristics stated in the description below and in the following claims .

A tool for connecting or disconnecting tubulars near a drill floor in accordance with the invention comprises a power tong and a backup tong, the tool being located at the same level as or below the drill floor.

Preferably the tool comprises a closed power tong arranged to grip a tubular and spin the threaded portion of the tubular into or out of a complementary threaded portion of an adjacent tubular. The adjacent tubular is kept stationary by

a backup tong.

The power tong is also arranged to tighten a threaded connection to a specific torque, and also to undo a made-up threaded connection.

The mutual spacing between the backup tong and the power tong is controlled by at least one feed cylinder. When the tongs have gripped their respective tubulars the feed cylinder is placed in a passive state, allowing the mutual displacement of the pipe tongs to follow the thread pitch of the pipe joints without the tongs being subjected to any significant axial forces.

The backup tong can be displaced in the axial direction of the tubular, and during connection and disconnection it is displaced towards and away from the power tong, respectively.

Advantageously the tool is provided with the equipment required for automatic pipe handling, cooperation with the mousehole elevator, the so-called rabbit, making it relatively simple to perform the connection and disconnection operations without manual control . Connecting and disconnecting tubulars on the drill floor is relatively heavy work, which may involve a risk of personal injury when carried out manually.

A device in accordance with the invention frees up valuable space on the drill floor, while cooperation with the mousehole elevator facilitates a more automated connecting operation. The device is also well suited for other connecting and disconnecting purposes, especially when it comes to freeing up floor space on the drill floor.

The following describes a non-limiting example of a preferred embodiment illustrated in the accompanying drawings, in which :

Fig. 1 is a schematic side view of a section of a drilling device where a tool for connecting and disconnecting tubulars is arranged in accordance with the invention;

Pig. 2 shows in a larger scale the area around the tool of figure 1, a first tubular in the mousehole machine being held in the backup tong, while a second tubular is suspended over the tool, ready to be connected;

Fig. 3 is a similar view to figure 2, but here the second tubular is arranged in the power tong; and

Fig. 4 is a perspective view of the tool.

In the drawings, reference number 1 denotes a section of a drilling device comprising a drill floor 2 and a main module deck 4, the drilling centre 6 of the drilling device 1 extending through the drill floor 2 and the main module deck 4.

A mousehole machine 8 is arranged in the drill floor 2, comprising a mousehole well 10 and a mousehole tube 12, the mousehole tube 12 being equipped with a mousehole elevator 14.

A tool 16 for connecting and disconnecting tubulars,

hereinafter designated a tool, is located in the mousehole well 10, at the same level as the drill floor 2, see figure 2. The tool 16, which is attached to the mousehole well 10 by a fitting 17, comprises a power tong 18 and a backup tong 20.

A first tubular 22 is placed in the mousehole tube 12 and is displaced, manually or automatically, to the desired vertical position in the backup tong 20 through use of the mousehole elevator 14.

The first tubular 22 is gripped by means of the hydraulic cylinders 24 of the backup tong 20 and held there in a fixed position during the subsequent connecting operation.

A second tubular 26 is lowered towards the power tong 18, the power tong 18 and its gripping cylinders 28 have been moved to their upper position by hydraulic feed cylinders 30, see figure 2.

The second tubular 26 is lowered and gripped by means of the gripping cylinders 28 of the power tong 18, whereupon the power tong 18 by means of hydraulic motors 32, via a gear rim 34, spins the threaded pin 36 of the second tubular 26 into the first tubular 22, while at the same time the feed cylinder 30 lowers the power tong 18, see figure 3. Then the tubulars 22, 26 are made up to a predetermined torque.

The first and second tubulars 22, 26 form a pipe stand which is then either lifted out of the mousehole for intermediate storage or, if a third tubular (not shown) is to be connected to the two tubulars (22, 26), lowered further into the mousehole machine 8 by means of the mousehole elevator 14.

Disconnection of tubulars involves the same operations as those described above, but in reverse order.