TUBULAR WITH SCREW THREAD

Abstract

The invention relates to an improved filament-reinforced tubular, and a method for providing such a tubular. A filament-reinforced tubular according to the invention comprises a tubular body (2), the tubular body comprising multiple fibre mats (10) encapsulated in a thermoset material (11), and is at least at one end provided with a male screw thread (3) comprising threading. According to the invention, the threading comprises a core member (12, 16). Furthermore, the threading comprises one or more fibre mats (13) that cover the core member. The one or more fibre mats are pulled between the windings of the core member by a positioning wire (14). The core member, the one or more fibre mats, and the positioning wire, are encapsulated by a, preferably thermoset, cover material (15), which cover material defines the shape of the screw thread.

Claims

1-26. (canceled)

27. A filament-reinforced tubular, comprising: a tubular body, the tubular body comprising multiple fibre mats encapsulated in a thermoset material, wherein the tubular body is at least at one end provided with a male screw thread, the screw thread comprising threading, with a threading base and a threading top, and a root groove, with a root base as a bottom, between the threading, wherein the threading comprises a core member, the core member having multiple windings around the tubular body, such that the windings of the core member are separated by the root base, and wherein the core member extends radially outwards relative to the root base, wherein the threading comprises one or more fibre mats that cover the core member, and wherein the one or more fibre mats are pulled between the windings of the core member and onto the root base by a positioning wire, and wherein the core member, the one or more fibre mats, and the positioning wire, are encapsulated by a cover material, the cover material defining the shape of the screw thread.

28. The filament-reinforced tubular according to claim 27, wherein the core member is created by machining the root groove in the tubular body, cutting through multiple fibre mats in the tubular body, such that the core member is formed by a part of the tubular body, the part of the core member comprising multiple fibre mats encapsulated in a thermoset material.

29. The filament-reinforced tubular according to claim 27, wherein the core member is a strand of filament material, the strand of filament material extending over the tubular body, and thus over the fibre mats comprised in the tubular body, and along a length of the threading.

30. The filament-reinforced tubular according to claim 27, wherein the core member is a strand of filament material, the strand of filament material extending along a length of the threading, and wherein the threading further comprises: a core member anchoring area, wherein the anchoring area is an anchoring groove that is machined in the tubular body, the anchoring groove cutting through multiple fibre mats in the tubular body, and wherein the windings of the anchoring groove are separated by the root base, wherein the core member is partially located in the anchoring area, and forms the core of the threading.

31. The filament-reinforced tubular according to claim 27, wherein the screw thread is provided on a tapered end section of the tubular, wherein the tapered end section cuts through multiple fibre mats encapsulated in the thermoset material of the tubular body.

32. The filament-reinforced tubular according to claim 27, wherein the tubular body is made by way of centrifugal or rotational casting a thermosetting material.

33. The filament-reinforced tubular according to claim 27, wherein the tubular is further provided with a torque-lock mounting area adjacent the screw thread, wherein the mounting area is provided with grip enhancing surface features for securing a torque lock against rotation about the longitudinal axis of the tubular, and wherein the grip enhancing surface features comprise multiple parallel rib elements and/or parallel slots, for cooperating with rib elements and/or slots provided on the inside of the torque lock, for securing the torque lock against rotation about the longitudinal axis of the tubular.

34. A riser section, comprising: two of the filament-reinforced tubulars according to claim 27 and a coupling sleeve connecting the two tubulars, wherein the coupling sleeve comprises a screw thread at opposite ends for cooperating with the screw thread provided on the tubulars, and wherein the tubulars are each with one end screwed into the coupling sleeve.

35. A riser section, comprising: two of the filament-reinforced tubulars according to claim 27; and a coupling sleeve connecting the two tubulars, wherein the coupling sleeve comprises a screw thread at opposite ends for cooperating with the screw thread provided on the tubulars, and wherein the tubulars are each with one end screwed into the coupling sleeve, wherein the tubular is further provided with a torque-lock mounting area adjacent the screw thread, wherein the mounting area is provided with grip enhancing surface features for securing a torque lock against rotation about the longitudinal axis of the tubular, wherein the grip enhancing surface features comprise multiple parallel rib elements and/or parallel slots, for cooperating with rib elements and/or slots provided on the inside of the torque lock, for securing the torque lock against rotation about the longitudinal axis of the tubular, wherein the riser section further comprises two torque locks, wherein the torque locks are mounted each on a tubular, on opposite ends of the coupling sleeve, wherein the torque locks are on an inside surface provided with grip enhancing surface features for engaging the grip enhancing surface features of the torque-lock mounting area of the tubulars, and wherein the torque locks engage the coupling sleeve such that they block rotation of the torque locks relative to the coupling sleeve, to thus secure the respective tubulars against rotation relative to the coupling sleeve.

36. The riser section according to claim 35, wherein the torque locks engage the coupling sleeve such that they, while blocking rotational movement, allow for axial movement of the torque locks, and thus of the tubulars, relative to the coupling sleeve, and thus allow for elongation of the sections of the tubulars comprising the screw thread, when the tubulars are loaded in an axial direction.

37. The riser section according to claim 34, wherein the screw thread of the coupling sleeve and the screw thread of the respective tubulars is configured to compensate for elongation of the tubulars, wherein the pitch of the screw thread of the tubulars increases in a direction away from the end of the tubular, and the pitch of the screw threads of the coupling sleeve increases in a direction towards the end of the coupling sleeve, such that, when the tubulars are screwed into the coupling sleeve and the torque locks have been mounted to secure the rotational movement of the tubulars relative to the coupling sleeve: in an unloaded condition, when there is no or only a limited axial load on the tubulars; only a limited number of windings, for the tubular windings located near the end of the tubular and for the coupling sleeve windings located away of the end of the coupling sleeve, is in engagement; during an increase in axial load on the riser section, the tubulars, and the section of the tubular comprising the screw thread, elongates, and an increasing number of windings of the tubulars come into engagement with the windings of the coupling sleeve; and in a fully loaded condition, when there is a significant axial load on the tubulars, all windings, for the tubular also the windings located away from the end of the tubular and for the coupling sleeve also the windings located near the end of the coupling sleeve, are in engagement.

38. The riser section according to claim 34, wherein the coupling sleeve is provided with one or two sealing rings, such that the tubulars, when screwed into the couplings sleeve, abut a sealing ring with an outer end thereof.

39. A bore hole provided with a string of tubulars, the tubulars being the filament-reinforced tubular according to claim 27.

40. A method for providing a filament reinforced tubular with a screw thread, wherein the screw thread comprises threading, the threading having a threading base and a threading top, and a root groove between the threading, the root groove having a root base as a bottom, and wherein the filament reinforced tubular comprises a tubular body, the tubular body comprising multiple fibre mats encapsulated in a thermoset material, the method comprising: providing the tubular with a core member for the threading, the core member having multiple windings around the tubular body, such that the windings of the core member are separated by the root base, and wherein the core member extends, at least partially, radially outwards relative to the root base; winding one or more fibre mats around the core member and the root groove; winding a positioning wire into the root groove, thus pulling the one or more fibre mats between the windings of the core member and onto the root base; inserting fibre mat covered end of the tubular into a mould, wherein the mould defines the final shape of the screw thread; injecting a thermoset cover material under pressure into a cavity between the end of the tubular and the mould, thus encapsulating the core member, the one or more fibre mats, and the positioning wire, and thus defining the shape of the screw thread; after a setting period, increasing pressure in the thermoset cover material to remove air bubbles from the mould; and removing the tubular from the mould.

41. The method according to claim 40, further comprising creating the core member for the threading by machining the root groove in the tubular body, thus cutting through multiple fibre mats in the tubular body, such that the core member for the threading is formed by part of the tubular body, the part of the core member comprising multiple fibre mats encapsulated in a thermoset material.

42. The method according to claim 40, further comprising providing the core member as a strand of filament material, and winding the strand of filament material around the tubular body such that the strand of filament material extends over the tubular body, and thus over the fibre mats comprised in the tubular body, and along a length of the threading to be provided.

43. The method according to claim 40, further comprising: creating a core member anchor area by machining an anchoring groove in the tubular body, and cutting through multiple fibre mats in the tubular body, such that the windings of the anchoring groove are separated by the root base; and providing the core member as a strand of filament material, and winding the strand of filament material in the anchoring groove around the tubular body, such that the strand of filament material extends along a length of the threading to be provided, and such that the core member is partially located in the anchor area, to form the core of the threading.

44. The method according to claim 40, wherein the positioning wire is received in a strip shaped fibre mat, and wherein the strip shaped fibre mat is wound around the tapered part of the tubular such that the subsequent windings of the strip shaped fibre mat overlap each other.

45. The method according to claim 40, wherein the tubular body of the filament reinforced tubular is obtained by rotational casting.

Description

[0084] In the drawings:

[0085] FIG. 1 schematically shows a side view of an exemplary embodiment of a filament-reinforced tubular according to the in the invention;

[0086] FIG. 2 schematically shows an enlarged partial side view in cross section of threading of the exemplary embodiment of a filament-reinforced tubular of FIG. 1;

[0087] FIG. 3 schematically shows an enlarged partial side view in cross section of threading of an alternative exemplary embodiment of a filament-reinforced tubular;

[0088] FIG. 4 schematically shows an enlarged partial side view in cross section of threading of another alternative exemplary embodiment of a filament-reinforced tubular;

[0089] FIG. 5 schematically shows a side view of an exemplary embodiment of a riser section comprising two filament-reinforced tubulars coupled via a coupling sleeve according to the in the invention; and

[0090] FIG. 6 schematically shows an enlarged partial exploded view in cross section of the exemplary riser section of FIG. 5.

[0091] FIG. 1 shows a side view of a filament-reinforced tubular 1 according to the claimed invention. The filament reinforced tubular 1 comprises a tubular body 2.

[0092] It is submitted that such a filament-reinforced tubular is in particular suitable for use in a geothermal well bore, i.e. for contrasting a riser to be suspended in a well bore of a geothermal facility.

[0093] According to the invention, the filament-reinforced tubular 1 is provided with screw thread 3, more in particular a tubular body is provided with screw thread. In the embodiment shown, the tubular body 2 is at both ends, on tapered end sections of the tubular body, provided with male screw thread 3. The screw thread is built on the tubular body, as will be explained below.

[0094] FIG. 2 schematically shows an enlarged partial side view in cross section of threading, and part of the tubular body 2, of the screw thread of the filament-reinforced tubular of FIG. 1;

[0095] The screw thread 3 comprises threading 5. The threading has a threading base 6, a threading top 7, and a root groove 8, with a root base 9 as a bottom, located between the threading 5.

[0096] The tubular body 2 comprising multiple fibre mats 10 encapsulated in a thermoset material 11.

[0097] According to the invention, the threading 5 comprises a core member 12. The core member 12 has multiple windings around the tubular body 2, such that the windings of the core member are separated by the root base 9. The core member 12 forms the core of the threading, and extends radially outwards relative to the root base 9.

[0098] The threading 5 comprises one or more fibre mats 13, in the embodiment shown multiple fibre mats depicted as a single layer of fibre mats, that cover the core member 12. The fibre mats 13 are pulled between the windings of the core member 12 and onto the root base 9 by a positioning wire 14.

[0099] The core member 12, the one or more fibre mats 13, and the positioning wire 14, are encapsulated by a thermoset cover material 15, which cover material defines the shape of the screw thread 3.

[0100] In the exemplary embodiment shown in FIG. 1 and FIG. 2, the core member 12 is created by machining the root groove 8 in the tubular body 2, cutting through multiple fibre mats 10 in the tubular body 2, such that the core member 12 is formed by a part of the tubular body. The core member 12 comprises multiple fibre mats 13 encapsulated in a thermoset material.

[0101] In this embodiment, the core member 12 is an integral part of the original tubular body 2, and is a continuation of the material configuration of that tubular body. More in particular, the layered structure of the fibre mats 10 in the tubular body continues 2 in the core member 12. Covering the core member with multiple fibre mats 13 and the cover material 15 provides a threading with increased strength and allows for a good load transfer between the threading and the tubular body.

[0102] In an alternative embodiment, shown in FIG. 3, the core member 12 is a strand of filament material 16, for example a yarn of reinforcement fibres. The strand of filament material 16, depicted in cross section perpendicular to the length of the strand, extends over the tubular body 2, and thus over the fibre mats 10 in comprised in the tubular body, and along a length of the threading.

[0103] In this embodiment, the core member 12 is provided as a separated body, i.e. strand 16, which separate body is integrated in the threading. Providing the core member 12 in the form of a strand of filament material, extending along the threading, provides the threading with a continuous structure and thus contributes to the overall strength of the threading. In particular because the orientation of the threading is parallel to the threading.

[0104] In another alternative embodiment, shown in FIG. 4, the core member 12 is a strand of filament material 15, extending along a length of the threading, received in a core member anchoring area 17 of the tubular body 2.

[0105] The anchoring area 17 is created by machining an anchoring groove in the tubular body 2, cutting through multiple fibre mats 10 in the tubular body, such that the windings of the anchoring groove are separated by the root base 9. The core member 12 is partially located in the anchor area 17, extends in the radial direction relative to the tubular body and thus also extends partially in the threading. The core member is thus anchored in the tubular body and forms the core of the threading.

[0106] In this embodiment, the core member 12 is, similar to the embodiment shown in FIG. 3, provided as a separated body. In contrast with that embodiment, the core member is partially embedded in the structure of the tubular body. Thus the load transfer between the threading and the structure of the tubular body section is improved. Providing the core member in the form of a strand of filament material, extending along the threading, provides the threading with a continuous structure and thus contributes to the overall strength of the threading. In particular because the orientation of the threading is parallel to the threading.

[0107] FIG. 5 schematically shows a side view of an exemplary embodiment of a riser section 18 comprising two filament-reinforced tubulars 1, coupled via a coupling sleeve 19, according to the in the invention.

[0108] FIG. 6 schematically shows an enlarged partial exploded view in cross section of the exemplary riser section 18, depicting part of the tubulars 1, part of the coupling sleeve 19 connecting the two tubulars, part of two torque locks 20 mounted on the tubulars, and part of a sealing ring 21, located between the ends of the two tubulars.

[0109] The two filament-reinforced tubulars 1 are each, at tapered end sections 4, provided with screw thread 3. The coupling sleeve 19 comprises screw thread 22 at opposite ends for cooperating with the screw thread 3 provided on the tubulars 1. The tubulars are each with one end screwed into the coupling sleeve.

[0110] In the embodiment shown, the riser section 18 further comprising two torque locks 20. The torque locks 20 are each mounted on a tubular 1, on opposite ends of the coupling sleeve 19. The torque locks 20 are on an inside surface provided with grip enhancing surface features 23 for engaging grip enhancing surface features 24 of a torque-lock mounting area of the tubulars.

[0111] The torque locks 20 engage the coupling sleeve 19 such that they block rotation of the torque locks relative to the coupling sleeve 19, to thus secure the respective tubulars against rotation relative to the coupling sleeve.

[0112] In the embodiment shown, the torque locks 20 engage the coupling sleeve 19 such that they, while blocking rotational movement, allow for axial movement of the torque locks 20, and thus of the tubulars 1, relative to the coupling sleeve 19. The torque locks and the coupling sleeve thus allow for elongation of the sections of the tubulars comprising the screw thread, when the tubulars are loaded in an axial direction.

[0113] It is noted that due to the section of the tubulars being tapered, to connected the threading with multiple layers of fibre mats in the tubular body, under load the tapered section may not show a linear elongation profile. Preferably, the screw thread of the coupling sleeve and the tubulars is configured to establish a uniform load transfer between the tubulars and the coupling sleeve. Preferably, the pitch of the screw thread, i.e. the distance between adjacent windings, of the tubulars increases in a direction away from the end of the tubular, and the pitch of the screw threads of the coupling sleeve increases in a direction towards the end of the coupling sleeve, such that, when the tubulars are screwed into the coupling sleeve and the torque locks have been mounted to secure the rotational movement of the tubulars relative to the coupling sleeve: [0114] in an unloaded condition, i.e. when there is no or only a limited axial load on the tubulars, only a limited number of windings, i.e. for the tubular windings located near the end of the tubular and for the coupling sleeve windings located away of the end of the coupling sleeve, is in engagement; [0115] during an increase in axial load on the riser section, the tubulars, and in particular the section of the tubular comprising the screw thread, elongate, and an increasing number of windings of the tubulars come into engagement with the windings of the coupling sleeve; and [0116] in a fully loaded condition, i.e. when there is a significant axial load on the tubulars e.g. by the riser section supporting a riser handing in a bore hole, all windings, i.e. for the tubular also the windings located away from the end of the tubular and for the coupling sleeve also the windings located near the end of the coupling sleeve, are in engagement.

REFERENCE SIGNS

[0117] 01 filament-reinforced tubular [0118] 02 tubular body [0119] 03 screw thread [0120] 04 tapered end sections of the tubular body [0121] 05 threading [0122] 06 threading base [0123] 07 threading top [0124] 08 root groove [0125] 09 root base [0126] 10 fibre mats in tubular body [0127] 11 thermoset material [0128] 12 core member [0129] 13 fibre mats that cover the core member [0130] 14 positioning wire [0131] 15 thermoset cover material [0132] 16 strand of filament material [0133] 17 core member anchoring area [0134] 18 riser section [0135] 19 coupling sleeve [0136] 20 torque locks [0137] 21 sealing ring [0138] 22 screw thread coupling sleeve [0139] 23 grip enhancing surface features torque lock [0140] 24 grip enhancing surface features torque lock mounting area tubular