GB2101655A

GB2101655A - Device for locating control elements in well bores

Info

Publication number: GB2101655A
Application number: GB08116797A
Authority: GB
Inventors: Douglas Morrison
Original assignee: LASALLE PETROLEUM SERVICES LIM
Current assignee: LASALLE PETROLEUM SERVICES LIM
Priority date: 1981-06-02
Filing date: 1981-06-02
Publication date: 1983-01-19

Abstract

A locating device 11 comprises a pipe protector for protecting a flow pipe in a casing string in the bore of a well and locating a control element relative to the flow pipe. A body 12 of metal is hinged at 14 and is secured in place about the flow pipe by wedge 18 in slot 17. A resilient insert 23 of polymer compound is positioned in recess 22, and has at least one recess 25 for locating a control element such as an armoured coaxial cable. The insert 23 may be bonded or loosely positioned in the recess 22, but firmly held when the body 12 is tightened around the flow pipe. When the polymer deteriorates or is mechanically damaged, the insert can be removed and replaced without loss of the body 12. <IMAGE>

Description

SPECIFICATION Locating device The present invention relates to a locating device for use within a tubulular structure in a well bore and is concerned in particular but not exclusively with a locating device for locating a heavy armoured coaxial cable relative to a flow pipe within a casing string in a well bore.

In a well bore which is completed and in production, for example an oil or gas well, there is normally positioned within the well bore a casing string comprising a number of connected steel casing sections (known as casing joints), and within the casing string there is positioned a hollow cylindrical flow pipe through which the oil or other product is pumped. During the pumping operation, the casing and flow pipe are subjected to considerable vibration and lateral movement and it is well known to provide pipe protectors for locating the flow pipe within the casing and for protecting the flow pipe from damaging contact with the inner walls of the casing. These known pipe protectors commonly consist of a generally cylindrical sleeve of elastomeric material such as rubber, usually with a reinforcing framework or core embedded in the rubber.Usually these pipe protectors are split and are hinged or sprung to allow the protector to be opened and secured around the flow pipe. The protector is then secured in place, for example by a wedge shaped pin or tongue forced through inter-digitating apertured fingers.

It is also now standard practice to run down the space between the steel casing string and the inner flow pipe one or more control elements which may be hydraulic control lines and/or electrical cables. These control elements are used to monitor and control pumping and other equipment at the base of the well, and may monitor conditions in the well bore to detect and correct malfunction or damage. It is known to arrange for a pipe protector to constitute also a locating device for locating the control element or elements relative to the flow pipe. This may be achieved by providing in the elastomeric body of the pipe protector one or more recesses opening to an internal or external surface of the pipe protector for locating the control element or elements relative to the flow pipe.In other previously known arrangements where it has been required to locate a relatively large diameter, heavy control element such as an armoured coaxial cable, the cable has been located on the flow pipe by a metal strap around the pipe and has in effect been clamped or strapped against the flow pipe. Such an arrangement has a number of disadvantages due to friction and corrosion by electrolytic action.

Considering the arrangements in which an elastomeric pipe protector is also used to locate a control element such as a cable in a tubular structure such as casing string, the pipe protector is usually formed by a completely polymershrouded sheet-metal insert or sheet-metal shroud with polymer bonded inside the shroud.

This brings the disadvantage that the polymer tends to swell when in contact with hydrogensulphide in 'down hole' conditions. With the amount of polymer used in known protectors, the percentage swelling has an adverse effect on both the protector and security and the clearance between the flow tube and the casing wall. Where the pipe protector has the polymer bonded all round the protector, the polymer is normally scrap after its first application 'down hole', with only a small percentage being used a second time. It is therefore necessary to scrap both the metal and polymer of the part.

It is an object of the present invention to provide a locating device for use within a tubular structure such as a casing string in a well bore which is particularly, but not exclusively, applicable to locating relatively large diameter heavy control elements such as armoured coaxial cables, which device avoids or reduces the disadvantages set out above in relation to the known pipe protectors and locating devices.

According to the present invention there is provided a locating device for use within a tubular structure in a well bore, the device comprising a body in the general form of a sleeve or collar adapted to be secured around a flow pipe to locate and protect the flow pipe within a tubular structure in a well bore, and an insert of material different from that of the body positioned in a recess in the inner surface of the body, the insert having an opening for housing an elongate control element extending generally along the flow pipe and for locating the control element relative to the flow pipe.

Preferably the material of the insert is a relatively resilient material, conveniently an elastomeric material such as rubber. Preferably the material of the body is a relatively rigid material, conveniently a metal or metal alloy.

Most preferably the body is formed of cast alloy and the insert is a polymer insert, conveniently bonded into the recess in the body. Conveniently the body is in the form of a sleeve for encompassing a flow pipe, the sleeve being split and being openable at the split to be placed around the flow pipe and secured thereto. The body may be hinged to open at the split or may be sprung to be opened by deforming the body.

Conveniently the locating device serves the function of a pipe protector for locating a flow pipe relative to the tubular structure and for protecting the pipe from adverse contact with the inner surface of the tubular structure which may for example be a casing string. The invention has particular application where the body is adapted to be secured around a single flow pipe, and has a single generally cylindrical major internal surface adapted to engage and seat against the said flow pipe. Also the insert may have more than one recess for housing control elements, and in a particularly preferred arrangement the insert has one major recess for housing a control element of relatively large diameter (e.g. an armoured coaxial cable) and minor recesses for smaller elements (e.g. hydraulic control lines).

Preferably the body has an internal surface adapted to engage and seat against a flow pipe in operation, and in such an arrangement it is preferred that the said recess in the insert comprises a slot sufficiently deep, and appropriately shaped, to be such that when the locating device is secured about a flow tube, a control element located in the recess is gripped in a position such that the control element is spaced from the surface of the flow tube. Such an arrangement is advantageous in preventing or inhibiting contact of the control element with the flow tube thus preventing or reducing damage due to friction, impact, or corrosion by electrolytic action.

The present invention, at least in preferred embodiments thereof, provides a number of advantages over known device by virtue of provision of the insert in the body of the locating device, especially where the insert is of polymer material as is preferred. When the polymer deteriorates or is mechanically damaged, the insert can be removed and a new polymer insert moulded in its place, having the same or different line configurations, i.e. for locating different elongate control elements. A shape of insert and body can be adopted such that a very small are of polymer is left exposed to the elements. The unit is adaptable over a wider range of 'down hole' configurations with fewer tooling requirement, and simple and efficient tooling characteristics can be provided. Should an outer alloy case forming the said body become damaged, it can be re-cycled.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawing which shows a perspective view of a locating device embodying the invention. A locating device 11 embodying the invention comprises a pipe protector for a flow pipe in a casing string in the bore of a well such as an oil well. As has been referred to hereinbefore, when a well bore is in production there is normally positioned within the well bore a casing string and within the casing string is positioned a hollow cylindrical flow pipe through which the oil or other product is pumped. If the flow pipe were to remain free within the casing, the ensuing movement during pumping would cause severe wear of both the pipe and casing.It is therefore normal practice to provide pipe protectors secured around the flow pipe and made of rubber or other elastomeric material to protect the flow pipe from striking the side of the casing. It is also common practice to use such pipe protectors to locate within the space between the flow pipe and the casing control elements such as hydraulic control lines. In this embodiment of the invention there is provided a novel and advantageous construction of pipe protector which acts as a locating device. The protector will now be described in detail with reference to the drawings, but the general use of such protectors in well operations will not be described in detail, since such use is normal practice.

The locating device 11 comprises a body 12 of cast alloy which is hinged about a hinge 14 and can be opened to allow the body 12 to be placed around a flow pipe (not shown). At the opening or split of the body 12 two sets of fingers 1 5 and 16 extend around the wall of the body and when the body 12 is closed, the fingers 1 5 and 1 6 interdigitate. The fingers 1 5 and 1 6 are apertured at 17 to allow the body 12 to be tightened around a flow pipe by insertion of a wedge shaped pin 1 8 which is forced into position for example by striking with a hammer.

When in the closed position shown in Figure 1, the body'1 2 forms an internal generally cylindrical surface 21 which is adapted to engage and seat around the flow pipe in operation. Opening from the internal surface 21 is a crescent shaped recess 22 which extends along the length of the body 1 2 (along the direction of the axis of the cylindrical surface 21). Positioned within the recess 22 is an insert 23 formed of a polymer compound, which may be loosely positioned or may be bonded in the recess. If loosely positioned, the insert is held firmly in place when the body 12 is fitted in use around a flow pipe.

Positioned within the insert 23 is a recess 25, which opens from an internal surface 21 of the insert which continues the internal surface 21 of the body 12. The recess 25 is adapted to house and locate a control element such as an armoured coaxial cable (not shown).

The recess 25 has parallel sides leading to the internal surface 21, and in operation the coaxial cable (not shown) is slotted into position in the recess 25 but is not held there until the body 12 is tightened around the flow pipe by the tapered pin 1 8. During this tightening process the side walls of the recess 25 are squeezed inwardly and locate the cable in the recess 25 with a stand-off from the flow pipe.

Referring again to the arrangement of the insert 23, it is to be noted that the insert 23 is slightly domed at the top and bottom at 26 so as to fit within inwardly extending lips on the main body 12, of which the upper lip 27 is shown in the figure. A corresponding lip is provided at the bottom of the body 12, but is not shown in the figure.

Claims (Filed 2 June 1982) 1. A locating device for use within a tubular structure in a well bore, the device comprising a body in the general form of a sleeve or collar adapted to be secured around a flow pipe to locate and protect the flow pipe within a tubular structure in a well bore, and an insert of material different from that of the body positioned in a recess in the inner surface of the body, the insert having an opening for housing an elongate control element extending generally along the flow pipe and for locating the control element relative to the flow pipe.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. cable) and minor recesses for smaller elements (e.g. hydraulic control lines). Preferably the body has an internal surface adapted to engage and seat against a flow pipe in operation, and in such an arrangement it is preferred that the said recess in the insert comprises a slot sufficiently deep, and appropriately shaped, to be such that when the locating device is secured about a flow tube, a control element located in the recess is gripped in a position such that the control element is spaced from the surface of the flow tube. Such an arrangement is advantageous in preventing or inhibiting contact of the control element with the flow tube thus preventing or reducing damage due to friction, impact, or corrosion by electrolytic action. The present invention, at least in preferred embodiments thereof, provides a number of advantages over known device by virtue of provision of the insert in the body of the locating device, especially where the insert is of polymer material as is preferred. When the polymer deteriorates or is mechanically damaged, the insert can be removed and a new polymer insert moulded in its place, having the same or different line configurations, i.e. for locating different elongate control elements. A shape of insert and body can be adopted such that a very small are of polymer is left exposed to the elements. The unit is adaptable over a wider range of 'down hole' configurations with fewer tooling requirement, and simple and efficient tooling characteristics can be provided. Should an outer alloy case forming the said body become damaged, it can be re-cycled. An embodiment of the invention will now be described by way of example with reference to the accompanying drawing which shows a perspective view of a locating device embodying the invention. A locating device 11 embodying the invention comprises a pipe protector for a flow pipe in a casing string in the bore of a well such as an oil well. As has been referred to hereinbefore, when a well bore is in production there is normally positioned within the well bore a casing string and within the casing string is positioned a hollow cylindrical flow pipe through which the oil or other product is pumped. If the flow pipe were to remain free within the casing, the ensuing movement during pumping would cause severe wear of both the pipe and casing.It is therefore normal practice to provide pipe protectors secured around the flow pipe and made of rubber or other elastomeric material to protect the flow pipe from striking the side of the casing. It is also common practice to use such pipe protectors to locate within the space between the flow pipe and the casing control elements such as hydraulic control lines. In this embodiment of the invention there is provided a novel and advantageous construction of pipe protector which acts as a locating device. The protector will now be described in detail with reference to the drawings, but the general use of such protectors in well operations will not be described in detail, since such use is normal practice. The locating device 11 comprises a body 12 of cast alloy which is hinged about a hinge 14 and can be opened to allow the body 12 to be placed around a flow pipe (not shown). At the opening or split of the body 12 two sets of fingers 1 5 and 16 extend around the wall of the body and when the body 12 is closed, the fingers 1 5 and 1 6 interdigitate. The fingers 1 5 and 1 6 are apertured at 17 to allow the body 12 to be tightened around a flow pipe by insertion of a wedge shaped pin 1 8 which is forced into position for example by striking with a hammer. When in the closed position shown in Figure 1, the body'1 2 forms an internal generally cylindrical surface 21 which is adapted to engage and seat around the flow pipe in operation. Opening from the internal surface 21 is a crescent shaped recess 22 which extends along the length of the body 1 2 (along the direction of the axis of the cylindrical surface 21). Positioned within the recess 22 is an insert 23 formed of a polymer compound, which may be loosely positioned or may be bonded in the recess. If loosely positioned, the insert is held firmly in place when the body 12 is fitted in use around a flow pipe. Positioned within the insert 23 is a recess 25, which opens from an internal surface 21 of the insert which continues the internal surface 21 of the body 12. The recess 25 is adapted to house and locate a control element such as an armoured coaxial cable (not shown). The recess 25 has parallel sides leading to the internal surface 21, and in operation the coaxial cable (not shown) is slotted into position in the recess 25 but is not held there until the body 12 is tightened around the flow pipe by the tapered pin 1 8. During this tightening process the side walls of the recess 25 are squeezed inwardly and locate the cable in the recess 25 with a stand-off from the flow pipe. Referring again to the arrangement of the insert 23, it is to be noted that the insert 23 is slightly domed at the top and bottom at 26 so as to fit within inwardly extending lips on the main body 12, of which the upper lip 27 is shown in the figure. A corresponding lip is provided at the bottom of the body 12, but is not shown in the figure. Claims (Filed 2 June 1982)

1. A locating device for use within a tubular structure in a well bore, the device comprising a body in the general form of a sleeve or collar adapted to be secured around a flow pipe to locate and protect the flow pipe within a tubular structure in a well bore, and an insert of material different from that of the body positioned in a recess in the inner surface of the body, the insert having an opening for housing an elongate control element extending generally along the flow pipe and for locating the control element relative to the flow pipe.

2. A device according to claim 1 in which the

material of the insert is a relatively resilient material and the material of the body is a relatively rigid material.

3. A device according to claim 1 or 2 in which the material of the insert is an elastomeric material.

4. A device according to any preceding claim in which the material of the body is a metal or metal alloy.

5. A device according to any preceding claim in which the body is formed of a metal and the insert is formed of a polymer material.

6. A device according to any preceding claim in which the insert is bonded into the recess in the body.

7. Apparatus according to any of Claims 1 to 5 in which the insert is loosely positioned in the recess in the body, the arrangement being such that the insert is held firmly in place when the body is fitted in use around a flow pipe.

8. A device according to any preceding Claim in which the body is in the form of a sleeve for encompassing a flow pipe, the sleeve being split and being openable at the split to be placed around the flow pipe and secured thereto.

9. A device according to any preceding Claim arranged also to serve the function ofa pipe protector for locating a flow pipe relative to the tubular structure and for protecting the pipe from adverse contact with the inner surface of the tubular structure.

1 0. A device according to any preceding Claim in which the insert has more than one recess for housing control elements, the insert having one major recess for housing an armoured coaxial cable of relatively large diameter, and one or more minor recesses for housing one or more smaller control elements.

11. A device according to any preceding Claim in which the said body has an internal surface adapted to engage and seat against a flow pipe in operation, and in which the said recess in the insert comprises a siot sufficiently deep, and appropriately shaped, to be such that when the locating device is secured about a flow tube, a control element located in the recess is gripped in a position such that the control element is spaced from the surface of the flow tube.

1 2. A device according to any preceding Claim in which the insert extends in a direction generally along an axis of the sleeve or collar, substantially from a top tp a bottom of the sleeve or collar, and in which the insert is slightly domed at the top and bottom so as to fit within inwardly extending lips on the said body at the top and bottom of the body.

1 3. A locating device substantially as hereinbefore described with reference to the accompanying drawing.