For long casing strings, cementing has to be car¬ ried out at several points along the length of the casing. One known method for achieving this is to place hydraulically actuated valves along the length of the casing. When cementing is complete the valves are shut and a tool is sent down the casing to smooth the surface of the casing where each valve is situated. This method is time consuming and expensive. Another method is to use sleeves held by shear pins over holes in the casing. When the holes are to be closed, forcing means are applied to each sleeve suffi¬ cient to break the shear pin and allow the sleeve to drop over its associated hole. A difficulty with this technique is providing satisfactory closure of the holes.

An object of at least preferred embodiments of the present invention is to reduce the problems associated with the prior art. Accordingly, the present invention provides a tool for use in wellbore operations, which tool comprises a cylindrical body having a wall provided with at least one hole for the passage of fluid therethrough, charac¬ terised in that said at least one hole is provided with a tubular member which projects into said cylindrical body and at least part of which is made from a ductile material which can be deformed to at least partially close said hole.

The tubular member is preferably of circular cross- section although it could be of other shapes, for

example oval or even rectangular although this is not recommended.

Preferably, said ductile material comprises metal, for example steel, copper, aluminium and bendable stain- less steel.

Advantageously, said wall is provided with a curved surface over which said tubular member can be deformed.

Advantageously, said tool comprises inflatable isolation means for isolating areas in said wellbore. Preferably, said inflatable isolation means commu¬ nicates with said at least one hole.

Advantageously, said tool comprises deforming means for deforming said ductile material.

Preferably, said deforming means are actuable by hydraulic pressure.

Advantageously, said deforming means are actuable by a bomb.

Preferably, said deforming means comprises a drive sleeve. Advantageously, when an axial force is applied to said drive sleeve, said drive sleeve rotates circumfer- entially and deforms said ductile material.

Preferably, said tool comprises a communicating sleeve displaceable to open fluid flow through said tubular member.

Advantageously, said tool comprises a closing sleeve for actuating said deforming means.

Preferably, said sleeves are releasably secured to one another and/or the cylindrical member.

For a better understanding of the present invention reference will now be made, by way of example, to the accompanying drawings, in which:

Fig. 1 is a longitudinal cross-sectional view of part of one embodiment of a tool in accordance with the present invention;

Fig. 2 shows the tool of Fig. 1 during deformation of the tubular member;

Fig. 3 is a longitudinal side view, partly in cross-section, showing a second embodiment of a tool in accordance with the present invention attached to the bottom of a length of casing;

Figs. 4, 5, 6 and 7 show, to an enlarged scale, details of the tool shown in Fig. 3; Figs. 8, 9, 10 and 11 show consecutive stages in the operation of the tool shown in Fig. 3;

Fig. 12 is a cross-sectional view taken on line XII-XII of Fig. 3;

Fig. 13 is a view similar to Fig. 12 but after deformation of the tubular member has occurred;

Fig. 14 is an enlarged view of a detail of Fig. 12;

Fig. 15 is an enlarged view of a detail of Fig. 13;

Fig. 16 is a cross-sectional view of a third embo¬ diment of a tool in accordance with the present inven- tion;

Fig. 17 is a view similar to Fig. 16 after deforma¬ tion of the tubular member has occurred;

Fig. 18 is an enlarged view of a detail of Fig. 16;

Fig. 19 is an enlarged view of a detail of Fig. 17; Fig. 20 is a fragmentary view, in section, of part of a fourth embodiment of a tool in accordance with the invention;

Figures 21 to 26 show various methods of attaching the tubular member to the cylindrical body; and Fig. 27 is a cross-sectional view of part of a

fifth embodiment of a tool in accordance with the inven¬ tion.

Referring to Fig. 1 of the drawings, there is shown part of a tool which is generally identified by refer- ence number 1. The tool 1 comprises a cylindrical body 2 having a wall 3 through which extends two holes 4. Each hole 4 is provided with a tubular member 5 made from a ductile material. As shown, fluid can pass freely through the holes 4. In order to inhibit the passage of fluid through holes 4 a bomb 6 is dropped down the cylindrical body 4.

Fig. 2 shows the bomb 6 deforming the tubular members 5. The bomb 6 acts pendicular to the tubular members 5, causing the tubular members to deform and seal the hole 4. The wall 3 of the cylindrical body 2 is provided with a curved surface 7 beneath each hole 4 in order to inhibit the lower surface of the tubular member 5 from splitting which would prevent the hole 4 being completely sealed. The upper surface of each tubular member 5 bends between the point of impact of the bomb 6, and the point of attachment of the tubular member 5 to the wall 3. The bomb 6 can be specially curved at its lower edge in order to improve contact with the tubular members 5. Suitable ductile materials for the fabrication of the tubular members 5 include steel, aluminium, copper and bendable stainless steel.

Referring now to Figures 3 to 11 there is shown a tool which is generally identified by reference numeral 101. The tool 101 is intended for the cementing of casing 108 in wellbore operations. Cementing involves the formation of an annulus of cement circumjacent the casing between the casing and the wellbore.

Prior to cementing, a number of tools 101 are low- ered into the wellbore (not shown) in a string of casing

at predetermined points along the string. Once the casing and tools 101 have reached the required position in the well, the cementing process is carried out se¬ quentially at each tool 101. Firstly a packer is inflated circumjacent the cylindrical body 102 of the tool 101 to form a platform for the cement. Secondly cement is pumped down the inside of the casing 108 and passes through holes in the tool to fill the annulus above the inflatable packer. Finally the holes are closed.

The cementing process is presented diagrammatically in Figures 8 to 11. The first stage is to inflate a packer circumjacent the casing to block the annulus. This is achieved by pumping a bomb 106 of a specific diameter down the casing 108 with inflation fluid until the bomb 106 impacts on surface 109 of a drive sleeve 111. The force of the impact breaks a shear pin 110, allowing the drive sleeve 111 to drop down into a second position (Fig.9). The downward travel of the drive sleeve 111 is limited by a locking member 112 which projects into a recess 113.

In this second position (Fig. 9), inflation fluid is diverted from flowing through the casing by bomb 106 through port 114 into recess 115 in the cylindrical body 102, and into cavity 116. The inflation fluid then passes through tubular member 105a and a channel 117, past a non return valve 118, into an inflatable packer 119 until the inflatable packer 119 blocks the annulus between the tool 101 and the wellbore. The next stage is to send cement down the casing 108 into tool 101. The cement acts, inter alia, on the upper and lower surfaces 140a, 140b of a communication sleeve 140. Since the surface area of the upper surface 140a is greater than the surface area of the lower surface 140b the cement exerts a net downward force on

the communication sleeve 140. In operation the cement exerts sufficient pressure to break a shear pin 141 and thereby allow the communication sleeve 140 to move downwardly uncovering hole 104 (Fig. 10). Cement can now pass through the tubular members 105 into the annulus between the casing 108 and the wellbore.

Once cementing is complete, a second bomb 120 (Fig. 11) of a larger diameter than the first bomb 106 is pumped down the casing 108. This impacts on the top surface of closing sleeve 121, shearing shear pin 122 and displacing the closing sleeve 121 downwardly. This releases locking member 112 and the downward force of the bomb 120 acting on the drive sleeve via closing sleeve 121 and communication sleeve 140 causes the drive sleeve 111 to move downwardly until it reaches end stop 123.

This complete action seals off both the tubular members 105 and 105a by deformation in a similar way to that described with reference to Fig. 2, except that the deforming member is the drive sleeve 111 which is actua¬ ted by the closing sleeve 121 which is in turn actuated by the second bomb 120.

Figures 4 to 7 show details of parts of the tool 101. Fig. 4 shows a longitudinal cross-sectional view of part of the wall 103, including both tubular members 105, 105a and the two recesses 113, 115.

Figures 5 to 7 show a longitudinal cross sections of the drive sleeve 111, the commuication sleeve 140, and the closing sleeve 121 respectively.

The drive sleeve 111 shown in Fig. 5 also shows slot 124 and cavity 116 in which the tubular members 105, 105a are respectively situated allowing movement of the drive sleeve 111 between a first position and a second position. A snap ring recess 126 is provided in

the drive sleeve 111, so that the drive sleeve 111 is held firmly by a snap ring 127 opening into the recess 115 during the the final sealing operation (Fig. 11).

Fig. 6 shows that the surface area at the top 140a of the communication sleeve 140 is greater than the surface area 140b at the bottom.

Figures 12 to 15 show views of the embodiment shown in Fig. 3 before and after the deformation of the tubu¬ lar members 105. Figures 16 to 19 show another embodiment of the invention, in which the drive sleeve 211 is rotated cir- cumferentially in the direction of the arrow (Fig. 17) in order to deform projecting tubular members 205, and hence to seal holes 204 in the cylindrical body 202. The rotation can be achieved by placing the drive sleeve 211 on a cam surface, which translates a longitudinal force into rotational motion.

Fig. 20 shows a variation on the embodiment of Fig. 3, in which the drive sleeve 311 is made up of two independent parts 311a and 311b. The difference in mode of operation being in the final stage, in which the second bomb 320 impacts closing sleeve 321 shearing shear pin 322. Closing sleeve 321 then travels down¬ wardly, its tail 335 engaging a shoulder 325 on the upper part 311a which moves downwardly and deforms the tubular member 305. A snap ring 381 stored in recess 382 expands into groove 383 to hold the upper part 311a in place. The closing sleeve 321 engages the communica¬ tion sleeve which in turn drives the lower part 311 of the drive sleeve downwardly until it engages a stop. However, a spring 385 biases a block 386 against the bottom of the tubular member 305 which is pinched toge¬ ther.

Fig. 21 shows one method of attachment of the tubular member 405, in which the tubular member has a

flange 426 and is retained against an abutment by a threaded collar 427.

Fig. 22 show another methods of attachment of the tubular member 505 where the tubular member is integral with a threaded portion 527 which is threadedly attached to the cylindrical body 502.

Fig. 23 shows another method of attachment of the projecting tubular members 605, where the tubular member has a flange 626 and is secured to the outer edge of the cylindrical body 602 by insertion of a push-fit plug 680.

Fig. 24 shows another method of attachment which is similar to that disclosed with reference to Fig. 22 except that the tubular member 705 comprises separate threaded portion 727 and tubular portion 705 which are secured together, for example by welding or adhesive.

Fig. 25 shows another method of attachment of the projecting tubular member 805, in which the tubular member is attached at the outer edge of the casing 801 by the use of a hollow wedge 880.

Fig. 26 shows another method of attachment of the tubular member 905, in which the tubular member is atta¬ ched at the outer edge of the cylindrical body 902 by welding, gluing or soldering means 980. Fig. 27 shows a longitudinal cross-sectional view of a similar embodiment to that shown in Fig. 3 with a different orientation of the projecting tubular member 1005. Said tubular member 1005 being angled down the cylindrical body 1002. This arrangement requires less deformation of the tubular member 1005 in order to seal the hole 1004.

In tests, satisfactory results have been obtained using tubular members with internal diameters ranging from 12 to 38mm, outer diameters ranging from 15 to 75mm and projections of 12 to 100mm. A particularly satis-

factory tubular member is made from bendable stainless steel with an internal diameter of 22mm, an outer dia¬ meter of 25mm and a projection of 44mm.