GB2048335A - A re-entry cementing float shoe - Google Patents

Abstract

A re-entry cementing float shoe (10) has short inner and outer cylindrical housing members (12, 11) with an annular space therebetween filled with a cement core (13). The inner top portion of the outer housing (11) has an attachment means (14) for accepting and attaching to a casing pipe. The top of the inner housing (12) has an inner diameter (20) capable of receiving and holding a cementing pipe string, followed by a first circular shoulder (21) sloping inwardly and downwardly. Threads (22) capable of receiving and holding a latch plug are on the inner surface of the inner housing (12) below the first shoulder (21) and, below the threads (22), are a locating means (24) and an orientation means (25) for a sonar/TV locating camera. Below these is a second circular shoulder (28) sloping outwardly and downwardly to receive a ball valve (27). Below said second shoulder (28) is a side pocket valve housing (26) the valve housing (26) extending downwardly and outwardly from the bore of the inner housing (12). The ball valve (27) has a density which is greater than water and less than the cement to be used. The side pocket housing (26) has a drain (29) communicating at all times with the space outside of the shoe. <IMAGE>

Description

SPECIFICATION A re-entry cementing float shoe The present invention relates to a re-entry cementing shoe and to a method of re-entering and cementing an underwater well or bore hole using a shoe.

Deep underwater re-entry of an established oil or natural gas or exploratory hole on the ocean floor is an established procedure. A number of methods-and apparatus have been developed to facilitate the procedure. One of the most costeffective methods involves the use of sonar and/or TV camera guidance systems to help locate the hole. In general a sring of pipe is lowered to within the vicinity of the hole, then a guidance system is lowered through the string of pipe so that the sensing devices are in position such that they can guide the string to and within the entrance of the hole. Once the sring is in the hole the guidance system is withdrawn and normal operations can be carried on. Such general guidance systems and methods are described in U.S. Patent No.

3 199 613 (issued August 10, 1965) and U.S.

Patent No. 4031 544 (issued June 21, 1977) which are incorporated herein, Other systems and methods are described in issues of Ocean Industry (August and June 1970) and are in Offshore (November 1970) and incorporated herein.

One of the problems associated with the reentry of a well or bore hole with a cementing shoe is that while a system for preventing the reverse flow of cement is desired, the system must allow easy entry of the guidance system through the cementing pipe string and subsequent easy withdrawal. A flapper valve has been used but this has the problem that it may become fouled against the camera, or it may damage the camera as it passes through.

It is an object of the present invention to provide a re-entry cementing float shoe capable of receiving and positioning a sonar and/or TV guidance system through the cementing piping string of the shoe.

According to this invention there is provided a re-entry cementing float shoe comprising an inner cylindrical housing member and an outer cylindrical housing member in concentric spaced relationship forming an annular space therebetween with a cement core filling said annular space, the inner housing member having its top below the top of the outer housing member, the upper surface of the cement core forming a tapered funnel, sloping inwardly and downwardly, the bottom of the funnel ending at the top of the inner housing member and the top of the funnel ending at the inner surface of the outer housing member, the top of the other housing member being equipped with a casing attachment means capable of attaching to a casing pipe string, the top of the inner surface of the inner housing member forming a female stabtype pipe string attachment means, a pump-down latch acceptor means disposed below said stabtype attachment means within the inner housing member and forming part of the inner housingbore consisting of a shoulder means sloping inwardly and downwardly, followed by a plurality of threads, followed by a smooth section, the threads being capable of interacting and holding a pump-down latch plug and the smooth section being capable of sealingly contacting with a pump-down latch plug, a sonar/TV camera seating means and a sonar/TV camera anti-rotational means disposed below said pump-down latch plug means. and a valve means disposed below said pump-down latch plug means and forming part of the inner housing bore consisting of a second shoulder means sloping outwardly and downwardly forming the top of a side-pocket ball valve housing having within it a ball valve, the side pocket extending downwardly and outwardly from the side of the inner housing member to a depth at least equal to the diameter of the ball valve, the side pocket being equipped with a conduit means forming a drain means extending from the bottom of the side pocket communicating at all times with the space outside of the shoe, the density of the ball valve being greater than water and less than the cement to be used with the shoe.

The use of a ball valve assembly to prevent backflow is advantageous. Such a valve can be easily moved out of the way by the entrance of the guidance system or could have a density such that it remains in a side pocket in water. Ball valve systems have been employed generally in pipe strings for example in U.S. Patents Nos.

3568768,2825412,2737 244,3332497, 3 269 463,3 584 645,3 850 191 and 3 850 1 94. Well and/or cementing systems have employed ball valve systems for example, in U.S.

Patent Nos 2 212 087, 2 320 670 and 3 616 850. Where these ball valve systems have pocket conduit systems to force the ball from the pocket to the seat, the conduit system opens into the bore of the piping systems.

None of the re-entry shoe systems use a ball valve, none of the ball valve systems use a pocket conduit means opening to space outside of the element, thus allowing draining outside of the shoe, lessening the chance of fouling, nor do any of the systems combine a ball valve with a latch down plug system. Finally, none of the art specifies the use of a ball valve with a density between seawater and cement.

According to a feature of this invention there is provided a method of re-entering an underwater hole and cementing within the underwater hole with a re-entry cementing float shoe comprising an inner cylindrical housing member and an outer cylindrical housing member in concentric spaced relationship forming an annular space therebetween with a cement core filling said annular space, the inner housing member having its top below the top of the outer housing member, the upper surface of the cement core forming a tapered funnel, sloping inwardly and downwardly, the bottom of the funnel ending at the top of the inner housing member and the top of the funnel ending at the inner surface of the outer housing member, the top of the other housing member being equipped with a casing attachment means capable of attaching to a casing pipe string, the top of the inner surface of the inner housing member forming a female stabtype pipe string attachment means, a pump-down latch acceptor means disposed below said stabtype attachment means within the inner housing member and forming part of the inner housing bore consisting of a shoulder means sloping inwardly and downwardly, followed by a plurality of threads, followed by a smooth section, the threads being capable of interacting and holding a pump-down latch plug and the smooth section being capable of sealingly contacting with a pump-down latch plug, a sonar/TV camera seating means and sonar/TV camera anti-rotational means disposed below said pump-down latch plug means, and a valve means disposed below said pump-down latch plug means and forming part of the inner housing bore consisting of a second shoulder means sloping outwardly and downwardly forming the top of a side-pocket ball valve housing having within it a ball valve, the side pocket extending downwardly and outwardly from the side of the inner housing member to a depth at least equal to the diameter of the ball valve, the side pocket being equipped with 9 conduit means forming a drain means extending from the bottom of the side pocket communicating at all times with the space outside of the shoe, the density of the ball valve being greater than water and less than the cement to be used with the shoe consisting essentially of attaching said shoe via the casing attachment-means to a casing pipe, lowering the shoe under water to the vicinity of the hole, stabbing a cementing pipe string into the female stab-type pipe string attachment means, positioning a sonar/TV camera guidance by lowering the guidance system through the cementing pipe string on to the sonar/TV camera seating means and anti-rotational means within the shoe, finding and entering the hole by moving the shoe in response to information received from the guidance system, withdrawing the guidance system, lowering the shoe within the hole to the desired depth by increasing the length of the pipe string, pumping in the desired amount of cement and checking the backward flow of cement by allowing the valve means to close and by pumping a pump-down latch plug down the cementing pipe string until threads on the latch plug have attached to the plurality of threads of the pumpdown latch plug acceptor means.

The invention can provide for the lowering of a shoe attached to a casing, the equalization of pressure within and outside the casing so that a ball valve drops into the bottom of its pocket allowing the introduction of a sonar/TV guidance system, finding and entering a previously drilled hole, withdrawing the guidance system, lowering the string into place within the hole, introducing cement, controlling back flow with a ball valve, pumping down and securing a wiping pump-down latch plug and coincidently sealing the shoe to reverse flow through the use of a ball valve.

An embodiment of this invention will now be described, by way of example, with reference to the accompanying drawings, of which: Figure 1 is a view partly in elevation and partly in vertical section illustrating a re-entry float for sonariTV Tool in accordance with the invention, and with the ball valve in the side pocket; Figure 2 is a view partly in elevation and partly in vertical section illustrating the shoe with the sonar/TV Tool inserted therein; Figure 3 is a view of a preferred sonar/TV guidance system seating and orientation means; Figure 4 is a view partly in elevation and partly in vertical section illustrating the shoe with the ball valve in its sealing position with a pump-down latch plug in place.

Referring to Figure 1 , the shoe referred to generally as 10 comprises an outer cylindrical member (shoe or short casing), 11, and an inner cylindrical member 12 in concentric spaced relationship forming an annular space partially filled with a cement core 13. The inner top of the outer member is equipped with an attachment means, 14, suitable for attaching to a casing pipe string. This outer member attachment means could be either threads for attaching to the threaded outer portion of a casing string or means for welding the casing string to the inner surface of the outer member. The remainder of the inner surface of the outer member is equipped with grooves, 15, for securing the cement core to the outer member.The top 16 of the inner member 12 is positioned below the lower portion of the outer member attachment means 14. While not necessary, the bottom of the inner member 1 7 preferably extends below the bottom of the outer member 18. The upper inner surface of the cement core 1 9 is tapered downwardly from the inner surface of the member below the outer member attachment means 14, preferably at a 450 angle, ending at the top of the inner member 1 6, thereby forming a cone orfunnel.

The top of the bore or inner surface of the inner member 12, is equipped with an attachment means 20, for receiving a stab-in cementing or drilling pipe string. Such a stab-type male member is usually equipped with O-ring seals.

Preferably 6-8/5 inches of the bore of the inner member 12, forms the female stab-type fitting means 20, with a bore diameter of preferably 4.94 inches. The bore of the inner member below the female stab-type attachment member 20, is equipped with a first circular shoulder means 21, sloping inwardly and downward, preferably at a 450 angle. The shoulder means 21 reduces the bore to preferably 3.375 inches. Below the shoulder the inner surface of the inner member is equipped with threads 22, and below the threads a smooth inner bore surface 25 for receiving and locking in prace a pump-down wiping latch plug usuaily equipped with O-ring seals. The shoulder means 21, threads 22, extending preferably about 2 inches down the bore of the inner member, 1 2.

Below the surface area 23, the bore is equipped with a sonar camera system seating means 24, and a sonar/TV camera system orienting means 25. The sonar/TV camera seating and orienting means 24 and 25 project into the bore of the inner member 12, preferably between about 21-5/32 and 21-21/32 inches from the end of the inner member 1 7. Below the sonar/TV camera system seating means 24 and orienting means 25, there is an optional shoulder means 37 sloping inwardly and downwardly. There is an optional shoulder means 37, which reduces the bore to 2.94 inches.

Below the shoulder means 37, and below the seating and orienting means 24 and 25, there is a side pocket valve housing 20 which communicates with the 4.94 inch bore and has a ball valve 27 therein. The side pocket valve housing 26 extends downwardly and outwardly at an angle from the bore of the inner member to a depth measured from the inner surface of the bore, at least equal to the diameter of the ball valve 27. Below the shoulder means 37, and the seating and/or orienting means 24 and 25 and above the side pocket means 26, there is a ball valve circular sealing/seating shoulder means 28 sloping downwardly and outwardly at an angle such that when the ball valve 27 is forced upward against the sealing/seating shoulder means 28, it forms a seal or seat preventing reverse flow.The shoulder seating and sealing means 28 increases the bore diameter to preferably 4.94 inches.

The ball valve 27 is made of material such that its density is greater than the water in which it is to operate but less than the cement which is to be pumped through the shoe.

A conduit 29 forming a drain means extends from the lower end of the pocket housing 26 in open communication with the space outside the shoe. The preferred embodiment is to have the end of the conduit which opens to the space 30 outside of the shoe, opening at the bottom of the shoe through the cement in between the bottom of the inner member 17 and bottom of the outer member 1 8. The drain 29 preferably extends at the same angle as the housing 26. The ball valve housing projects into the inner member bore to form a ball guide 31 essentially a partial inwardly and downwardly sloping shoulder means which decreases the bore to a diameter less than that of the ball valve 27 and directs the ball valve 27 into the lower portion of the ball valve housing 26.The ball guiding shoulder means 31 set at the same angle as the side pocket ball valve housing 26 and forming part of the bottom of the housing 26 reduces the bore of the inner member 12 to 3.25 inches.

Figure 2 shows the re-entry float cement shoe assembly 10, having been attached to a casing string 32 at the casing attachment means, 14 of the outer cylindrical member 11. While this casing attachment means 1 4 is shown as a female member it need not be so and could be a male member. The outer cylindrical member 11 surrounds an inner cylindrical member 12 with a central bore 33. The inner and outer members 11 and 12 form an annular space which is filled with cement, 1 3. The outer member is preferably made of a nondrillable metal while the inner member is prefeably made of a drillable material, preferably aluminum, plastic or cast iron.In a preferred embodiment the bottom of the inner member 17 extends below the bottom of the outer member 1 8. Figure 2 shows the cementing drill pipe string 34, having been stabbed into the female stab-type fitting 20 of the inner member 12. The sonar/TV camera 35, is shown having been lowered into the bore 33 in position to direct the shoe for re-entry.

The inner member 9 is equipped with a plurality of grooves 36 on its outer surface to anchor the inner member 12 2 in the cement 13 just as the outer member 11 is equipped with a plurality of grooves, 1 5 on its inner surface to anchor it to the cement 13.

The cone 1 9 guides the male stab-in portion of the cementing and/or drilling pipe string into the stab-type fitting 20 of the inner member 12.

Preferred seating means 24 and anti-rotation or orienting means 25 are shown in Figure 3. The camera seating and orientation means are the same means and are made of a plurality of lugs 38 which penetrates the inner member 1 2 with a projection 39 which protrudes into the bore of the inner member 12 about 1/4 inch. The protruding member 39 when viewed from the centre of the bore has a profile (as seen in Figure 3) where the bottom half is a semi-circle and the top half is a 900/450/450 triangle, the 900 angle forming the topmost part of the means, i.e., a line perpendicular with the bore and passing along the lug would bisect the 900 angle and pass through the centre of the semi-circle and the triangle. The base of the triangle and the top half of the semicircle are contiguous and preferably 0.687 inches long.

In Figure 2 the ball valve 27 is in the side pocket valve housing, 26 allowing the sonar/TV re-entry tool to pass through the bore of the inner member 12. The sonar/TV camera tool has been seated and oriented by the means, 24 and 25, which have locked on the seating and orienting means of the sonar/TV camera tool.

Figure 4 shows the shoe 10 after it has entered the well or hole, the sonar/TV camera tool has been removed, the shoe lowered into place, cement pumped into place and the pump-down latch plug 40 introduced.

In Figure 4 the ball valve 27 is seated against the means 28, thus preventing the reverse flow of fluid.

The preferred method of using the shoe involves attaching a casing pipe string 32 to the attaching means 14, lowering the shoe, 10, by increasing the length of the casing string to the desired length. When the desired casing pipe string is less than the depth of water over the well or hole to be re-entered, the shoe is lowered to the length of casing needed, then the drilling or cementing pipe string 34 stabbed into the stab-type fitting 20, and the shoe lowered further to the vicinity of the vvell head by increasing the drilling or cementing string.

If the casing is longer than the depth of the water over the well then the shoe is lowered to the vicinity of the well by the casing and the cement or drill pipe string 34 stabbed into the fitting 20.

The sonar/TV tool is lowered into the drilling or cementing piping string. The ball valve 27 is more dense than water, preferably more dense than sea water and less dense than the fluid, cement or mud, to be pumped down the well or hole. The density is between about 1.20 and about 1.40, preferably between about 1.20 and 1.30. The ball valve 27 may be in the closed position up against this seating shoulder, 28 or in the housing 26 depending on how carefully the shoe was lowered, i.e., depending on whether a water pressure differential was formed while lowering.

Once the shoe is in the vicinity of the hole to be re-entered, the sonar/TV camera is lowered into place on the seating means 24, and orienting means 26 of the shoe 10. The ball valve 27 remains out of the way or is moved out of the way easily by the sonar/TV camera tool into the side pocket ball valve housing 26.

The shoe 10 is positioned and lowered into the hole with the help of the sonar camera tool and then the camera tool is withdrawn, the ball valve 27 remains in the housing out of the way as the tool is withdrawn. The shoe 10 is lowered into place by increasing the pipe(s) string. Once in place the desired amount of cement is pumped down the cementing pipe string 34, through the bore 33 and the conduit 29, then wiping pumpdown latch plug is pumped down and it forms a seal with the bore directly below the threads 22 and is held in place by the threads. The ball valve 27 which is less dense than the cement in which it now finds itself floats up out of its pocket, helped by the backward flow of the cement through the conduit 30 and the bore 33, to form an additional seal at the shoulder sealing means 28.

While the shoe is described in terms of use with only cement, it should be recognized that the shoe could be advantageously used where further drilling was needed. In that case the density of the ball valve should be greater than the water in which it is used but less than the other liquids, drilling mud and cement, to be used in the hole.

After entering the hole and withdrawing the TV/sonar guidance system, a drill is lowered into place, drilling is carried out, the drill removed and the cementing operation completed as described above.

While Figures 1,2 and 4 have shown one preferred embodiment of the re-entry shoe, it is possible in another embodiment to switch the placement within the inner housing of the ball valve and its ball valve housing with the camera seating and orientating means. Thus, in another embodiment of the invention moving down the bore of the inner housing, one would find a first shoulder means sloping downwardly and in inwardly, followed by a series of threads on the inner surface of the inner housing followed by a smooth surface for sealing with the pump-down latch plug just as shown in Figures 1,2 and 4.

Instead of placing the camera seating and orientating means above the ball valve housing, the next member would be the second shoulder means (sloping outwardly and downwardly) and forming a seating and sealing means for the ball valve and the top of the ball valve housing which would follow. Again the pocket of the ball valve housing would extend down and at an angle from the bore of the inner housing. The conduit would communicate outside of the shoe by communicating with the bottom of the pocket and passing through the cement core and through the outer housing, preferably at the same angle as the pocket projects from the inner housing bore. The camera seating and orientating means would be below the ball valve housing in the bore of the inner housing. This would require either an adjustment of the length of the shoe, the length of the camera or the position of that portion of the camera with the camera seating and orientating means interact.

In Figures 1, 2 and 4 the top of the outer housing has been shown as having a female casing attachment means but in another embodiment of the invention this could also be a male attachment means. If it were a male attachment means then the top of the cement core which forms the funnel could be contiguous with the top of inner surface of the outer housing.

Claims (11)

1. A re-entry cementing float shoe comprising an inner cylindrical housing member and an outer cylindrical housing member in concentric spaced relationship forming an annular space therebetween with a cement core filling said annular space the inner housing member having its top below the top of the outer housing member, the upper surface of the cement core forming a tapered tunnel, sloping inwardly and downwardly, the bottom of the funnel ending at the top of the inner housing member and the top of the funnel ending at the inner surface of the outer housing member, the top of the other housing member being equipped with a casing attachment means capable of attaching to a casing pipe string, the top of the inner surface of the inner housing member forming a female stabtype pipe string attachment means, a pump-down latch acceptor means disposed below said stabtype attachment means within the inner housing member and forming part of the inner housing bore consisting of a shoulder means sloping inwardly and downwardly, followed by a plurality of threads, followed by a smooth section, the threads being capable of interacting and holding a pump-down latch plug and the smooth section being capable of sealingly contacting with a pump-down latch plug, a sonar/TV camera seating means and a sonar/TV camera anti-rotational means disposed below said pump-down latch plug means, and a valve means disposed below said pump-down latch plug means and forming part of the inner housing bore consisting of a second shoulder means sloping outwardly and downwardly forming the top of a side-pocket ball valve housing having within it a ball valve, the side pocket extending downwardly and outwardly from the side of the inner housing member to a depth at least equal to the diameter of the ball valve, the side pocket being equipped with a conduit means forming a drain means extending from the bottom of the side pocket communicating at all times with the space outside of the shoe, the density of the ball valve being greater than water and less than the cement to be used with the shoe.

2. A float shoe according to claim 1 where the valve means is below the sonar/TV camera seating means and anti-rotational means.

3. A float shoe according to claim 1 or claim 2 where the conduit means communicates with the space outside of the shoe by extending from the bottom of the side pocket and through the bottom of the cement core, between the inner and outer housing members.

4. A float shoe according to any of claims 1 to 3 where the casing attachment means is a female casing attachment means and the top of the cement core tapered funnel ends below the female casing attachment means at the inner surface of the housing member.

5. A float shoe according to any of claims 1 to 4 where the plurality of threads forming part of the pump-down latch plug means are righthanded.

6. A float according to any of claims 1 to 5 where the inner housing member is made of drillable material.

7. A float shoe according to any of claims 1 to 6 where the density of the ball valve is between about 1.20 and about 1.40.

8. A method of re-entering an underwater hole and cementing within the underwater hole with a re-entry cementing float shoe comprising an inner cylindrical housing member and an outer cylindrical housing member in concentric spaced relationship forming an annular space therebetween with a cement core filling said annular space, the inner housing member having its top below the top of the outer housing member, the upper surface of the cement core forming a tapered funnel, sloping inwardly and downwardly, the bottom of the funnel ending at the top of the inner housing member and the top of the funnel ending at the inner surface of the outer housing member, the top of the other housing member being equipped with a casing attachment means capable of attaching to a casing pipe string, the top of the inner surface of the inner housing member forming a female stab-type string attachment means, a pump-down latch acceptor means disposed below said stab-type attachment means within the inner housing member and forming part of the inner housing bore consisting of a shoulder means sloping inwardly and downwardly, followed by a plurality of threads, followed by a smooth section, the threads being capable of interacting and holding a pump-down latch plug and the smooth section being capable of sealingly contacting with a pump-down latch plug, a sonar/TV camera seating means and a sonar/TV camera anti rotational means disposed below said pump-down latch plug means, and a valve means disposed below said forming part of the inner housing bore consisting of a second shoulder means sloping outwardly and downwardly forming the top of a side-pocket ball valve housing having within it a ball valve, the side pocket extending downwardly and outwardly from the side of the inner housing member to a depth at least equal to the diameter of the ball valve, the side pocket being equipped with a conduit means forming a drain means extending from the bottom of the side pocket communicating at all times with the space outside of the shoe, the density of the ball valve being greater than water and less than the cement to be used with the shoe consisting essentially of attaching said shoe via the casing attachment means to a casing pipe, lowering the shoe under water to the vicinity of the hole, stabbing a cementing pipe string into the female stab-type pipe string attachment means, positioning a sonar/TV camera guidance by lowering the guidance system through the cementing pipe string on to the sonar/TV camera seating means and anti-rotational means within the shoe, finding and entering the hole by moving the shoe in response to information received from the guidance system, withdrawing the guidance system, lowering the shoe within the hole to the desired depth by increasing the length of the pipe string, pumping in the desired amount of cement and checking the backward flow of cement by allowing the valve means to close and by pumping a pump-down latch plug down the cementing pipe string until threads on the latch plug have attached to the plurality of threads of the pumpdown latch plug acceptor means.

9. A method according to claim 8 where the valve means of the shoe is below the sonar/TV camera seating means and anti-rotational means, the conduit means passes through the bottom of the cement core, between the inner and outer housing members, the casing attachment means is a female casing attachment means, the top of the tapered funnel ends below the casing attachment means at the inner surface of the outer housing member, the plurality of threads forms parts of the pump-down latch plug means are right handed and the density of the ball valve is between about 1.20 and about 1.40.

10. A re-entry cementing shoe substantially as hereinbefore described with reference to the accompanying drawings.

11. A method of re-entering an underwater hole and cementing within the underwater hole with a re-entry cementing float shoe substantially as hereinbefore described with reference to the accompanying drawings.