DUAL TOOL SPIDER FOR PIPES

Abstract: A dual string spider is described which consists of general­ ly hemispherical first and second body portions (2,3) respec­ tively, each defining respective dual receiving apertures (5,6) passing therethrough. The portions (2,3) are hingedly connect­ ed at a vertical hinge (4) at one side and at the other side a piston (9) and a cylinder (10) is disposed coupled to respective brackets (7,12) which in turn are coupled to portions (2,3) of the cylinder respectively. The piston is actuatable to separate the centres of the drilling strings to be distanced from each other by a distance sufficient to permit the required tong opera­ tion on make up of a pip joint on one strip without engagement of the other adjacent string by the nose of the tong.

Description: DUAL IDOL SPIDER FOR PIPES This invention relates to an apparatus for handling pipes or tubes during assembly of lengths of tubular pipe to form a string. Normally a tubing string is made up of a number of interconnected pipes or tubes. Each tube is capable of being made up by connecting an externally screw-threaded male end of one tube into an internally screw-threaded female end of another tube. The various interconnected lengths of tube in the form of a string are then fed down a bore hole. The string is raised and lowered from the bore hole using a well-known system of elevators and spiders. Such elevators and spiders are mounted above a drill rig floor and in order to assemble a string the upper end of a section of pipe is engaged by an elevator and raised sufficiently above a string to allow the new section of pipe to be made up with the upper end of the string by means of a tong. During this movement the upper end of the string is held against rotation by a spider incorporating gripping elements known as slips. When the string with new pipe section attached is then lowered into the borehole, the string is first released by the spider and the string lowered by the elevator. It is well known to employ elevators and spiders which can handle dual strings i.e. a pair of parallel strings arranged to be fed down a single borehole. In such dual string arrangements, the nose of the tong, during make up on one string, tends to engage the adjacent string unless the two strings are forced apart. To date, such separation is effected by any convenient means and in many cases is carried out merely by inserting a rigid element between the strings and forcing them apart. This can result in damage to the tubes of the strings and can frequently be dangerous to personnel engaged in the operation. An object of the present invention is to provide an improved form of spider for dual string systems. According to the present invention there is provided a dual string spider comprising first and second body portions each defining a string receiving aperture therethrough and hingedly connected tbgether at one side thereof, and actuator means for separating the two body portions about their hinge by a predetermined amount whereby, in use, the distance between strings passing through the aperture in each body portion can be varied. Preferably, the actuator means is a piston and cylinder device connected between the first and second body portions. An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing which is a diagramatic perspective view of a spider according to the present invention. Referring to the drawing, a spider for a dual string system comprising a rigid spider body e.g, of steel which is formed in two cooperating portions 2 and 3 hinged together , , &commat; at 4. Each portion 2 and 3 in its closed position as shown in the drawing defines a pair of slip bowls 5,6.adapted to operatively surround a pair of adjacent parallel strings. Gripping elements or slips (not shown) are adapted to be located in each slip bowl 5, 6 in known manner. The first portion 2 of the spider has welded thereto an outwardly extending bracket 7 having a vertical pivot pin 8 extending therethrough. Connected to the pivot pin 8 is the outer end of a piston 9 which is associated with an hydraulic cylinder 10 whose other end is pivotably mounted on a vertical pivot pin 11 carried by a bracket 12 which is welded to the second portion 3 of the spider. Each portion 2 and 3 of the spider is mounted on a flat plinth 13 through the intermediary of rollers (not shown) which facilitate movement of each of the two portions of the spider over the surface of the plinth 13. In operation of the spider of the invention, the dual parallel strings operatively associated with the slip bowls 5, 6 during normal operation can be separated from each other by actuation of the piston and cylinder device 9, 10 to cause the centres of the drilling strings to be distanced from each other by a distance sufficient to permit the required tong operation on make up of a pip joint on one string without engagement of the other adjacent string by the nose of the tong. For example, in an arrangement wherein the slip centres are spaced from each other by 6.25 during normal operation in the closed position, the slip centres can be increased in their spacing to 8.25" at approximately 100 psi. The rollers carried by the underside of each portion 2, 3 of the spider permits the two portions 2 r 3 of the spider to be separated from each other about the hinge 4 by movement over the surface of the plinth 13 utilising considerably less power than would otherwise be the case.

Claims: CLAIMS: 1. A dual string spider comprising first and second body portions each defining a string receiving aperture therethrough and hingedly connected together at one side thereof, and actuator means for separating the two body portions about their hinge by a predetermined amount whereby, in use, the distance between strings passing through the aperture in each body portion can be varied. 2. A dual string spider as claimed in claim 1 wherein the actuator means is a piston and cylinder device connected between the first and second body portions. 3. A dual string spider as claimed in claim 1 or claim 2 wherein said first and said second body portions are mounted on a plinth via roller means for facilitating movement of each of said first and second portions of the spider over the plinth surface. 4. A dual string spider as claimed in any preceding claim wherein said first and second body portions have respective brackets coupled thereto and adapted to be engaged with said actuator means. 5. A dual string spider as claimed in any preceding claim wherein said first and second body portions are coupled to a common hinge which is arranged to be substantially vertical in use and parallel with said strings. 6. A dual string spider as claimed in any one of claims 2 to 5 wherein the piston and cylinder are coupled to vertically disposed pins.

Inventors: SKENE, WILLIAM
Applicants: SALVESEN OILFIELD TECH LTD
Application year: 1986
Main classification: E21B19
IPC codes: E21B19, E21B33