Pipe tour arrangement and assembly procedure

Abstract

Tubing arrangement for a deep borehole, with - an outer tube tour part (1) and - an inner tubular tour part (2) which is at least partially accommodated in the outer tubular tour part (1), wherein the outer tubular tour part (1) and the inner tubular tour part (2) can be sealed against each other via at least one seal (D) and each extend along a central axis (M), characterized in that the inner tubular tour part (2) comprises a seal carrier (20) for the at least one seal (D) and a clamping element (21), wherein the clamping element (21) can be locked on the outer tubular tour part (1) and can be axially displaced along the central axis (M) relative to the seal carrier (20) within the outer tubular tour part (1) in order to apply an axially acting prestressing force to the seal carrier (20), wherein - the clamping element (21) comprises an elastically displaceable connecting area (21A) for locking on the outer tubular part (1) and / or - the inner tubular part (2) comprises a coupling element (22) via which the clamping element (21) can be rotated to apply the pre-tensioning force and / or - the clamping element (21) is at least partially made of spring steel and / or - the sealing of the outer and inner pipe parts (1, 2) can be re-tensioned against each other via the tensioning element (21).

Description

[0001] The proposed solution relates in particular to a tubular assembly for a deep borehole and to an assembly method for a tubular assembly.

[0002] The use of different outer and inner casing sections in deep drilling is widely known. Especially in drilling for natural gas caverns, it is widely known to use so-called production packers to complete a deep borehole. In this context, the locking and sealing of different casing sections against each other, subject to play a key role. This typically results in significant thermal and pressure-induced length changes in the casing section during subsequent operation. The associated relative movements of casing sections can lead to significant abrasion in the area of the seals provided for the casing section, thus negatively impairing the sealing effect.An additional difficulty with pipe tour arrangements in the area of deep drilling is that the individual pipe tour components have to be installed and sealed against each other at sometimes very great depths of several hundred meters.

[0003] Deep drilling rods are described, for example, in documents DE 186 081 A and DE 187 487 A.

[0004] Against this background, there is a need for an improved tube routing arrangement and an improved assembly method.

[0005] This problem is solved both by a tube assembly of claim 1 and by an assembly method of claim 15. The subclaims of the pending set of claims specify possible embodiments of the proposed solutions.

[0006] A proposed tubular tour arrangement for a deep borehole comprises an outer tubular tour part and an inner tubular tour part, wherein the inner tubular tour part is at least partially received in the outer tubular tour part and the outer and inner tubular tour parts can be sealed against one another via at least one seal. The tubular tour parts further extend along a central axis, wherein the proposed solution provides that the inner tubular tour part comprises a seal carrier for the at least one seal and a clamping element. The clamping element on the inner tubular tour part can be locked to the outer tubular tour part and can be axially displaced within the outer tubular tour part relative to the seal carrier along the central axis in order to apply an axially acting prestressing force to the seal carrier.

[0007] The basic idea of the proposed solution is the provision of a clamping element on the inner tubular part, which can be preloaded in a targeted manner and can transfer the necessary forces to the outer tubular part. The adjusted preload force can absorb any thermally and pressure-induced stress changes without causing any (significant) displacement of the seal carrier relative to the outer tubular part. The at least one seal provided on the seal carrier is thus not axially displaced during operation due to thermal or pressure factors, or at most only slightly, so that no functionally impairing wear can occur.The tensioning element can be locked to the outer pipe tour part separately from the seal carrier of the inner pipe tour part, thereby allowing a defined (locking) position to be assumed with respect to the outer pipe tour part while simultaneously allowing axial displacement with respect to the seal carrier when the desired preload force is applied to the seal carrier. In this way, thermally or pressure-induced expansion or contraction on the inner pipe tour part relative to a fixed point can be reduced via the preloaded tensioning element, for example by any thermally or pressure-induced stress changes occurring during operation acting in the opposite direction to the applied preload force and thus being able to be reduced via the preloaded tensioning element. In this way, improved pipe tour anchoring and sealing can be achieved.

[0008] In one variant of the proposed solution, a shoulder of the inner tubular tour section rests on a stop shoulder on the outer tubular tour section during retraction. The pre-tensioning force between the stop shoulder and the clamping element allows any thermally and pressure-induced stress changes above the shoulder of the inner tubular tour section to be absorbed. Consequently, strains in the inner tubular tour section can be absorbed relative to a fixed point via the shoulder and the stop shoulder.

[0009] The proposed solution offers the particular advantage of allowing re-tensioning and re-sealing of the connection between the pipe sections even during operation without costly repair measures. In particular, at least one re-tensionable seal can be provided.

[0010] For example, one embodiment provides that the clamping element, together with the seal carrier, can be axially displaced along the central axis and relative to the outer tubular tour part into a locking position in which the clamping element is locked into engagement with the outer tubular tour part. The clamping element can then be displaced further axially from the locking position relative to the seal carrier (i.e., along the same adjustment direction as before) while maintaining engagement with the outer tubular tour part in order to apply the preload force to the seal carrier. When assembling the tubular tour arrangement, for example, the outer tubular tour part is first placed in the bore before the inner tubular tour part with seal carrier and clamping element is then inserted into the outer tubular tour part along the central axis.In this case, it is provided, for example, that the clamping element is displaced by an adjusting force applied to the seal carrier, for example by the clamping element being connected to the seal carrier in a form-fitting and / or force-fitting manner, and possibly even being held to the seal carrier in a form-fitting and / or force-fitting manner.

[0011] If the seal carrier and the clamping element are displaced far enough that at least one seal of the seal carrier is sealingly abutting an inner surface of the outer tubular tour part, the clamping element assumes the locking position. The outer and inner tubular tour parts are thus configured in this embodiment such that the clamping element is in a locking position, in which the clamping element is brought into locking engagement with the outer tubular tour part when the seal carrier assumes a predetermined sealing position with respect to the outer tubular tour part. The clamping element can then be displaced further axially into the bore relative to the seal carrier, for example, using a coupling element of the inner tubular tour part.As a result, the clamping element can apply a preload force to the seal carrier remaining in the sealing position while maintaining support on the outer pipe part and support on the seal carrier.

[0012] In particular, in this context, it can be provided that a sealing region of the seal carrier carrying the at least one seal is axially spaced from an end region of the seal carrier, on which at least one section of the clamping element is provided and which the clamping element projects axially beyond with at least one section.

[0013] One design variant of a proposed tube assembly provides that the clamping element can be axially displaced with a contact section against a stop on the seal carrier. By engaging the stop of the seal carrier, the clamping element can apply an axially acting preload force to the seal carrier upon (further) axial displacement along the central axis. The inner and outer tube assembly parts can be coordinated and configured in such a way that the clamping element only comes into contact with the stop of the seal carrier when the seal carrier assumes a relative position with respect to the outer tube assembly part in which the at least one seal is positioned as intended. Starting from a locking position then assumed by the clamping element, the clamping element can then be further axially displaced until it reaches the stop of the seal carrier in order to apply the desired preload force to the seal carrier.

[0014] In principle, the clamping element can already be brought into contact with the stop on the seal carrier upon reaching its locking position. However, one design variant provides a defined adjustment path that the clamping element must (further) bridge in the axial direction in order to be brought into contact with the stop on the seal carrier. This design variant facilitates subsequent separation of the inner tubular tour part from the outer tubular tour part. For example, it enables complete unscrewing of the clamping element from an internal thread of the outer tubular tour part without any axial movement of the inner tubular tour part during unscrewing.

[0015] For example, the stop is provided at an end region of the seal carrier, which is axially spaced along the central axis from a sealing region of the seal carrier that has the at least one seal. For example, an (end-side) stop of the seal carrier is formed by an at least local diameter enlargement on the seal carrier, in particular by a shoulder or extension that projects radially outward at least locally. Alternatively, the seal carrier can be formed as a separately manufactured, radially outwardly projecting stop element that is fixed to an end shaft journal of the seal carrier.

[0016] To specify a defined mounting position of the clamping element on the seal carrier, in which the clamping element, together with the seal carrier, can be displaced along the central axis relative to the outer tubular part until the locking position is reached, at least one positioning element is provided in one embodiment. The clamping element is connected to the seal carrier in a form-fitting and / or force-fitting manner via this at least one positioning element. The at least one positioning element thereby secures the clamping element against axial displacement relative to the seal carrier until the locking position is reached.

[0017] In principle, the at least one positioning element can be designed to be displaceable in order to specifically allow a displacement of the clamping element relative to the seal carrier once the locking position has been reached. However, particularly in deep drilling, such a displaceability, possibly also a controlled (mechanically or electronically switchable) adjustment, of a positioning element cannot be easily implemented and in particular not without considerable cost. Against this background, a possible further development provides at least one predetermined breaking point on the at least one positioning element, at which the positioning element specifically fails to prevent a displacement of the clamping element relative to the seal carrier. Thus, the at least one positioning element or its predetermined breaking point can be configured to fail when an axial force on the positioning element exceeds a predetermined threshold value.If the positioning element breaks along its at least one predetermined breaking point, the axial securing between the clamping element and the seal carrier is removed and the clamping element can be further axially displaced from the locking position relative to the seal carrier in order to apply the preload force to the seal carrier.

[0018] In principle, the clamping element can be rotated about the central axis in order to further axially displace the clamping element from the locking position relative to the seal carrier and thereby apply the preload force to the seal carrier. This includes, for example, that once the locking position is reached, there is a threaded connection between the outer tubular part and the clamping element, so that by rotating the clamping element about the central axis, the clamping element can be further axially displaced, supported by the corresponding threaded connection, in this case relative to the seal carrier. By means of such an axial displacement of the clamping element relative to the seal carrier, the axial force mentioned above can then, for example, also be applied to at least one positioning element, so that a positive and / or non-positive securing of the clamping element to the seal carrier that existed until the locking position is reached is released.

[0019] For fixation to the outer tubular tour part, in one embodiment according to the invention, the clamping element can comprise an elastically displaceable connecting region. A section of the clamping element then snaps into a section of the outer tubular tour part provided for this purpose via this elastically displaceable connecting region when the locking position is reached. For example, the connecting region has at least one locking tooth and / or the external thread already mentioned above. Because the connecting region has a certain inherent elasticity, the connecting region can initially be elastically displaced by a certain amount during assembly of the tubular tour arrangement when the seal carrier, together with the clamping element, is displaced axially relative to the outer tubular tour part in the direction of the locking position of the clamping element.Under the effect of a restoring force, the connecting area can then automatically lock onto the outer tubular part when the locking position is reached.

[0020] In this context, it can also be provided, for example, that the clamping element with its connecting region is configured to be elastically displaced at least once radially inward and radially outward during a joint axial displacement of the seal carrier and the clamping element for assuming the locking position relative to the central axis. The radially outward displacement occurs, for example, under the action of the elastic restoring force if a displacement of the connecting region has previously occurred radially inward, with the connecting region sliding onto or striking a radially inwardly projecting section of the outer tubular part.

[0021] In order to prevent undesired (elastic) displacement of the connecting region of the clamping element after reaching the locking position and the subsequent application of the preload force to the seal carrier, the seal carrier in one embodiment has at least one support section that locally projects radially outwards with respect to the central axis. The elastically displaceable connecting region of the clamping element is spaced from the support section by an outer circumferential surface of the seal carrier until the locking position is reached and is thus radially elastically displaceable inwards in the direction of the outer circumferential surface. A defined gap can be formed between the connecting region and the outer circumferential surface for the spacing. This gap can accordingly be designed in an annular manner surrounding the central axis.

[0022] As already explained above, according to a further embodiment of the invention, the inner tubular tour part can comprise a coupling element, via which the clamping element can be rotated to apply the preload force. Such a coupling element can be provided, for example, outside the seal carrier. The coupling element is then located, for example, below the seal carrier in a bore direction when the tubular tour arrangement is being assembled. The coupling element can, for example, be coupled to a work string in order to selectively rotate the clamping element when the clamping element has assumed its locking position. For example, the coupling element is designed as a screw shoe.

[0023] Alternatively or additionally, the coupling element can have a coupling region that faces an axial end of the seal carrier and is connected to the clamping element. For example, a rotationally fixed connection to the clamping element is realized via the coupling element. In particular, the coupling element can then be screwed to the clamping element at the coupling region.

[0024] In view of the special requirements of the clamping element with regard to its lockability on the outer tubular part and its axial displaceability relative to the seal carrier in order to apply a preload force to the seal carrier, it can be advantageous to form the clamping element from a different material than, for example, the seal carrier or any coupling element that may be present. According to a further embodiment of the invention, the clamping element is formed at least partially from spring steel. By manufacturing it from spring steel, for example, it is comparatively easy not only to ensure that the clamping element is sufficiently strong for the forces that occur. Rather, it also easily achieves, for example, the above-mentioned elastic displaceability of a connecting area for targeted locking of the clamping element to the outer tubular part when the locking position is reached.

[0025] For specifying the locking position and in particular the engagement between the clamping element and an inner surface of the outer tubular part, at least one toothing with locking teeth and locking grooves and / or a threaded engagement can be provided.

[0026] Another aspect of the proposed solution concerns a method for assembling a tubing assembly in a deep well. A proposed method includes at least the following steps: - Providing an inner tube tour part, - Providing an outer tube tour part in which the inner tube tour part is at least partially accommodated, - Inserting the outer tubular tour part into a bore along a central axis and then inserting the inner tubular tour part into the outer tubular tour part along the central axis, and - Sealing the outer tube tour part and the inner tube tour part against each other using at least one seal.

[0027] Here, the inner tubular tour part comprises a seal carrier for the at least one seal and a clamping element, wherein the clamping element is locked to the outer tubular tour part during assembly of the tubular tour arrangement and an axially acting pre-tensioning force is applied to the seal carrier by axially displacing the clamping element within the outer tubular tour part relative to the seal carrier along the central axis, wherein - the clamping element (21) comprises an elastically displaceable connecting area (21A) for locking on the outer tubular part (1) and / or - the inner tubular part (2) comprises a coupling element (22) via which the clamping element (21) can be rotated to apply the pre-tensioning force and / or - the clamping element (21) is at least partially made of spring steel and / or - the sealing of the outer and inner pipe parts (1, 2) can be re-tensioned against each other via the tensioning element (21).

[0028] In one embodiment of a proposed assembly method, the clamping element can, for example, be displaced axially together with the seal carrier along the central axis and relative to the outer tubular tour part into a locking position in which the clamping element is locked and engaged with the outer tubular tour part. Subsequently, the clamping element is further displaced axially relative to the seal carrier from the locking position while maintaining engagement with the outer tubular tour part in order to apply the preload force to the seal carrier. The locking and thus support on the outer tubular tour part enables a flow of force from the seal carrier via the clamping element into the outer tubular tour part.In this way, a defined preload force can be easily applied to the seal carrier without the need to subsequently insert additional elements into the deep bore from outside the bore. Both the locking of the clamping element on the outer pipe section and the application of the preload force can be easily controlled from the outside, i.e., from outside the bore.

[0029] During the proposed assembly process, the clamping element can be locked to the outer tubular tour part (in particular via a threaded connection or screw connection provided for this purpose) and this locking can be released without external tensile and compressive forces on the connecting elements provided for this purpose. Accordingly, the assembly process naturally includes anchoring the inner tubular tour part to the outer tubular tour part to transfer tensile and / or compressive forces from the inner to the outer tubular tour part after the outer tubular tour part has been inserted into the bore.

[0030] In particular, an embodiment variant of a proposed method can be carried out using an embodiment variant of a proposed tube tour arrangement.

[0031] Accordingly, the advantages and features explained for design variants of a proposed pipe run arrangement also apply to design variants of a proposed assembly method and vice versa.

[0032] The attached figures illustrate possible embodiments of the proposed solution.

[0033] Here we show: Fig. 1A shows a partial and sectional view of an embodiment of a proposed pipe assembly in a state during assembly on a vertically extending deep borehole, wherein the pipe assembly is intended to absorb loads occurring in particular during operation and at the same time provide a seal; Fig. 1B-1E enlarged views of areas B, C, D and E of the Fig. 1A; Fig. 2A the pipe tour arrangement of the Fig. 1A in a subsequent phase of assembly in which the outer and inner tube tour parts of the tube tour arrangement are already sealed against each other and partially connected; Fig. 2B-2E enlarged scale sections of areas B, C, D and E of the Fig. 2A; Fig. 3A the pipe tour arrangement of the Fig. 1A and Fig. 2A with an axially further displaced clamping element of the inner tube tour part in order to apply a preload force to the seal carrier of the inner tube tour part while simultaneously supporting the clamping element on the outer tube tour part and on the seal carrier; Fig. 3B-3F enlarged views of areas B, C, D, E and F of the Fig. 3A.

[0034] The attached Fig. 1A to 3F show in different views different phases during assembly of an embodiment variant of a proposed tube tour arrangement R with an outer tube tour part 1 and a multi-part inner tube tour part 2. The inner tube tour part 2 comprises in addition to a seal carrier 20 a clamping element in the form of a clamping sleeve 21 for applying a pre-tensioning force to the seal carrier 20 when the tube tour arrangement R according to the Fig. 3A to 3F is installed as intended.

[0035] To apply the pre-tensioning force, the inner tube section 2 comprises a coupling element in the form of a screw shoe 22. This screw shoe 22 is rotatable - for example via a working string - about a central axis M of the tube section arrangement R within the bore and is coupled to the clamping sleeve 21 in such a way that the clamping sleeve 21 is also rotated. If the clamping sleeve 21 is already in a position selected from the Fig. 2A to 2D, in which the clamping sleeve 21 is snapped or engaged into an internal thread 120 of a connecting area 12 of the outer tubular tour part 1 via a spring-elastic connecting area 21A provided with an external thread 210, the rotary movement of the clamping sleeve 21 leads to an axial displacement of the clamping sleeve 21 relative to the seal carrier 20 carrying the seals D. The external thread 210 of the clamping sleeve 21 then meshes with the internal thread 120 of the outer tubular tour part 1, so that the clamping sleeve 21 is displaced axially along the outer tubular tour part 1 and along the seal carrier 20 of the inner tubular tour part 2 while rotating about the central axis M.Here, the clamping sleeve 21 is in engagement with the outer tube part 1 and, upon reaching a stop 204, is supported on the seal carrier 20, so that the further axially displaced clamping sleeve 21 can apply a desired preload force to the seal carrier 20.

[0036] The Fig. Figure 1A shows the tube tour arrangement R in a first phase of assembly. Here, the inner tube tour part 2 has been inserted axially along the central axis M into the outer tube tour part 1. As can be seen from the enlarged sections of the Fig. 1B, Fig. 1C, Fig. 1D and Fig. 1E for the corresponding areas of the Fig. As can be seen in Figure 1A, in this first phase there is still no mechanical connection between the outer tubular tour part 1 and the inner tubular tour part 2. Only the seals D on the seal carrier 20 are inserted into the designated area of the outer tubular tour part 2 for sealing.

[0037] A first engagement between clamping sleeve 21 and outer tube part 1 is in accordance with the Fig. 2A to 2E is achieved when the seal carrier 20 has been displaced along a bore direction / adjustment direction V so far into the bore that a shoulder 201 of the seal carrier 20 rests against a stop shoulder 11 of the outer tubular tour part 1. The seal carrier 2 is then in a sealing position in which seals D provided on a sealing area 200A of the seal carrier 20, here for example in the form of O-rings, rest sealingly against an inner circumferential surface of the outer tubular tour part 1.

[0038] In this case, the clamping sleeve 21 is positively secured to an end region 200B of the seal carrier 20 via a positioning element in the form of a shear pin 23. This shear pin 23 ensures a (pre-)positioning of the clamping sleeve 21 on the seal carrier 20 and thus an assembly position of the clamping sleeve 21 with respect to the seal carrier 20 in a first phase of the assembly of the tube assembly R.

[0039] The flexible connection region 21A of the clamping sleeve 21, which carries the external thread 210, is further supported on the radially projecting support section 202, so that the clamping sleeve-side connection region 21A has at least a slight radial distance from an outer circumferential surface of the seal carrier 20, and an annular gap exists between the outer circumferential surface of the seal carrier 20 and the circumferentially extending connection region 21A. In this way, an undesirable (elastic) displaceability of the connection region 21A of the clamping sleeve 21 after the locking position has been reached and the preload force has subsequently been applied to the seal carrier 20 can be prevented. The elastically displaceable connection region 21A is spaced from the support section 202 until the locking position is reached relative to an outer circumferential surface of the seal carrier 20, and is thus radially elastically displaceable inwardly in the direction of the outer circumferential surface.After reaching the locking position with the subsequent targeted failure of a predetermined breaking point on the shear pin 23, the clamping sleeve 21 is further screwed axially over the existing threaded connection. In doing so, the support section 202 on the seal carrier 20 slides toward the elastically displaceable connection area 21A of the clamping element and limits the possibility of elastic deformation of the clamping sleeve 21 to ensure force transmission via the threaded connection.

[0040] The Fig. 2B, Fig. 2C, Fig. 2D and Fig. 2E again show enlarged sections of the pipe tour arrangement R - here from the Fig. 2A visible areas B, C, D and E. The Fig. 2B illustrates the position of the shoulder 201 of the seal carrier 20 on the stop shoulder 11 of the outer tube part 1. The enlarged section of the Fig. 2C shows the initial locking or snapping of a part of the external thread 210, which is provided on the elastically displaceable connecting region 21A of the clamping sleeve 21, onto the internal thread 120 of the outer tubular part 1.

[0041] Here, as can be seen from the enlarged view of the Fig. 2D, the connecting region 21A is further kept spaced from the outer circumferential surface of the seal carrier 20 by the support on the radially outwardly projecting support section 202 of the seal carrier 20. Furthermore, according to the illustration of Fig. 2E the clamping sleeve 21 is still axially secured to the seal carrier 20 via the shear pin 23.

[0042] If, starting from a locking position for the clamping sleeve 21 defined in this way, the screw shoe 22 is rotated using the work string, this rotational movement is transmitted to the clamping sleeve 21 via a coupling region 220, where one end of the clamping sleeve 21 extends to a shoulder 221 of the screw shoe 22. By meshing with the external thread 120 of the outer tubular part 1, this rotational movement then leads to a further axial adjusting force on the clamping sleeve 1, as a result of which the shear pin 23 shears off. The shear pin 23 then no longer engages in an axially securing manner in a groove 203 on the end region 200B of the seal carrier 20. After the shear pin 23 has sheared off, the clamping sleeve 21 can thus be (further) displaced axially relative to the seal carrier 20 by rotating the screw shoe 22.

[0043] The axial displacement of the clamping sleeve 21, due to the rotary movement applied by the screw shoe 22, ends at a stop 204 on the seal carrier side (compare Fig. 3F). The clamping sleeve 21 abuts this radially projecting stop 204 with a second contact shoulder 214 when the clamping sleeve 21 has been adjusted axially to its maximum relative to the seal carrier 20. The desired preload force can now be applied.

[0044] The preload of the seal carrier 20 via the clamping sleeve 21 limits possible movements of the seals D in the event of a load change on the inner pipe section 2, thus contributing to the tightness of the connection between the pipe sections 1 and 2, even over long operating periods. The proposed pipe section arrangement R is therefore suitable not only for natural gas caverns, but also for other liquid and gaseous media, particularly for hydrogen caverns.

[0045] As a result of the axial displacement of the clamping sleeve 21 relative to the seal carrier 20, the connection area 21A with the external thread 210 has also been displaced in the adjustment direction V to such an extent that the connection area 21A is at least partially radially supported by the support section 202 of the seal carrier 20. The mutual engagement of the threads 120 and 210 of the outer tubular part 1 and the clamping sleeve 21 is thus supported in the then assumed (preloaded) position of the clamping sleeve 21. At the same time, the locking mechanism remains easily releasable for disassembly.

[0046] Because the connection is screwed together using a work string, both the preload and the loosening of the connection can be achieved without external tensile or compressive forces acting on a thread, meaning that a variant of the proposed solution can be used without restrictions even in deviated boreholes. If necessary, the connection can also be loosened using a work string for unscrewing the connection. Once the connection between pipe sections 1 and 2 has been completely unscrewed, the inner pipe section 2 can be removed.By providing a defined adjustment path which the clamping sleeve 21 must (further) bridge in the axial direction after being attached to the outer tubular tour part 1 in order to allow the shear pin 23 to fail and to bring the clamping sleeve 21 into contact with the stop 204 on the seal carrier 20, it is possible to separate the inner tubular tour part 2 from the outer tubular tour part 1 by completely unscrewing the clamping sleeve 21 from the internal thread 120 of the outer tubular tour part 1 without an axial movement of the inner tubular tour part 2.

[0047] In principle, for example, it can be provided that - the outer casing element 1 is part of a cemented casing element, a cemented liner or an enveloping casing element and can be inserted into a borehole together with the respective element, ie not separately on the work string; - the inner tube tour part 2 is part of an inner tube tour and is installed with it; - the pipe sections 1 and 2 are joined and sealed underground so that a closed annular space is created above the joint; - the inner and outer pipe sections 1, 2 are joined underground by means of a detachable mechanical connection, such as the one shown in the Fig. 1A to 3F visible threaded connection which can absorb compressive and tensile forces after the connection has been made; - Forces can be transferred from the inner pipe tour to the outer pipe tour or from the inner pipe tour part 2 to the outer pipe part 1 when assembly is completed.

[0048] After proper assembly, the seal carrier is preloaded in such a way that seal wear due to abrasion is eliminated or at least significantly reduced and movement between inner and outer pipe sections 1 and 2 is largely excluded.

[0049] In principle, the seals can be inserted under tension between the pipe sections 1 and 2 during the connection process. Alternatively, the seal can also be subsequently created by tightening the seals D. For example, the seals D are made of elastomer or soft metal seals. Such seals can be used both statically and subsequently.

[0050] Another important feature of the illustrated design variant is that the connection is screwed and unscrewed without external tensile and compressive forces acting on the thread. A thread subject to external tension is neither particularly easy to screw nor unscrew. Such external tension on the threaded connection, which would pose a major problem in underground screwing operations, especially in deviated boreholes, can be easily avoided with the proposed solution. List of reference symbols 1 Outer tube tour part 11 Stop shoulder 12 Connection area 120 internal thread 2 Inner tube tour part 20 seal carriers 200A sealing range 200B end area 201 paragraph 202 support section 203 Groove 204 stop 21 Clamping sleeve (clamping element) 21A connection area 210 external thread 212 First contact shoulder 214 Second contact shoulder 22 Screw shoe (coupling element) 220 coupling area 221 paragraph 23 Shear pin (positioning element) D Seal M central axis R pipe tour arrangement V Adjustment direction

Claims

[1] Casing arrangement for a deep borehole, with - an outer tube tour part (1) and - an inner tubular tour part (2) which is at least partially accommodated in the outer tubular tour part (1), wherein the outer tubular tour part (1) and the inner tubular tour part (2) can be sealed against each other via at least one seal (D) and each extend along a central axis (M), characterized by , that the inner tubular tour part (2) comprises a seal carrier (20) for the at least one seal (D) and a clamping element (21), wherein the clamping element (21) can be locked on the outer tubular tour part (1) and can be axially displaced along the central axis (M) relative to the seal carrier (20) within the outer tubular tour part (1) in order to apply an axially acting prestressing force to the seal carrier (20), wherein - the clamping element (21) comprises an elastically displaceable connecting area (21A) for locking on the outer tubular part (1) and / or - the inner tubular part (2) comprises a coupling element (22) via which the clamping element (21) can be rotated to apply the pre-tensioning force and / or - the clamping element (21) is at least partially made of spring steel and / or - the sealing of the outer and inner pipe parts (1, 2) can be re-tensioned against each other via the tensioning element (21). [2] Pipe tour arrangement according to claim 1, characterized by that the clamping element (21) with a contact section (214) is axially displaceable against a stop (204) on the seal carrier (20). [3] Pipe tour arrangement according to claim 2, characterized bythat the stop (204) is provided at an end region (200B) of the seal carrier (20) which is axially spaced along the central axis (M) from a sealing region (200A) of the seal carrier (20) having the at least one seal (D). [4] Pipe tour arrangement according to one of claims 1 to 3, characterized by that the clamping element (21) together with the seal carrier (20) along the central axis (M) and relative to the outer tubular part (1) is axially displaceable into a locking position in which the clamping element (21) is brought into locking engagement with the outer tubular part (1), and the clamping element (21), while maintaining the engagement with the outer tubular part (1), is axially displaceable further from the locking position relative to the seal carrier (20) in order to apply the pretensioning force to the seal carrier (20). [5] Pipe tour arrangement according to claim 4, characterized bythat the clamping element (21), for the locking engagement in the outer tubular part (1) in the locking position, comprises at least one locking tooth, at least one locking groove and / or an external thread (210) on an outer circumferential surface of the clamping element (21). [6] Pipe tour arrangement according to claim 5, characterized by that the outer tubular tour part (1) comprises at least one locking groove, at least one locking tooth and / or an internal thread (120) on an inner circumferential surface of the outer tubular tour part (1) for the locking engagement of the clamping element (21). [7] Pipe tour arrangement according to one of claims 4 to 6, characterized by that the clamping element (21) is connected to the seal carrier (20) in a form-fitting and / or force-fitting manner via at least one positioning element (23), via which the clamping element (21) is secured against axial displacement relative to the seal carrier (20) at least until the locking position is reached. [8] Pipe tour arrangement according to claim 7, characterized by that at least one predetermined breaking point is provided on the positioning element (23), at which the positioning element (23) specifically fails to allow a displacement of the clamping element (21) relative to the seal carrier (20) in order to allow, starting from the locking position, a further axial displacement of the clamping element (21) relative to the seal carrier (20) for the application of the prestressing force. [9] Pipe tour arrangement according to one of claims 4 to 8, characterized by that the clamping element (21) is rotatable about the central axis (M) in order to further displace the clamping element (21) axially from the locking position relative to the seal carrier (20) and thereby apply the pre-tensioning force to the seal carrier (20). [10] Pipe tour arrangement according to one of claims 5 to 9, characterized by that the at least one locking tooth and / or the external thread (210) is provided on the connecting region (21A). [11] Pipe tour arrangement according to claim 10, characterized by that the clamping element (21) with its connecting region (21A) is configured to be elastically displaced radially inwards at least once and to be displaced radially outwards again when the seal carrier (20) and the clamping element (21) are displaced together axially to assume the locking position with respect to the central axis (M). [12] Pipe tour arrangement according to claim 11, characterized by in that the seal carrier (20) has at least one support section (202) which projects radially outwards locally with respect to the central axis (M), on which support section a section of the clamping element (21) can be supported in order to prevent the clamping element (21) from being displaced after the locking position has been reached and the prestressing force has subsequently been applied to the seal carrier (20). [13] Pipe tour arrangement according to one of the preceding claims, characterized bythat the coupling element (22) is provided outside the seal carrier (20) and / or faces an axial end of the seal carrier (20) with a coupling region (220) connected to the clamping element (21). [14] Pipe tour arrangement according to claim 13, characterized by that the coupling element (22) is firmly connected, in particular screwed, to the clamping element (21). [15] Method for assembling a tubular assembly (R) in a deep borehole, comprising the steps: - Providing an inner tube tour part (2), - providing an outer tubular tour part (1) in which the inner tubular tour part (2) is at least partially received, - Inserting the outer tubular tour part (1) into a bore along a central axis (M) and then inserting the inner tubular tour part (2) into the outer tubular tour part (1) along the central axis (M), - and - sealing the outer tubular tour part (1) and the inner tubular tour part (2) against each other via at least one seal (D), characterized by that the inner tubular tour part (2) comprises a seal carrier (20) for the at least one seal (D) and a clamping element (21) and the clamping element (21) is locked to the outer tubular tour part (1) during assembly of the tubular tour arrangement (R) and an axially acting prestressing force is applied to the seal carrier (20) by axially displacing the clamping element (21) within the outer tubular tour part (1) relative to the seal carrier (2) along the central axis (M), wherein - the clamping element (21) comprises an elastically displaceable connecting area (21A) for locking on the outer tubular part (1) and / or - the inner tubular part (2) comprises a coupling element (22) via which the clamping element (21) can be rotated to apply the pre-tensioning force and / or - the clamping element (21) is at least partially made of spring steel and / or - the sealing of the outer and inner pipe parts (1, 2) can be re-tensioned against each other via the tensioning element (21). [16] Method according to claim 15, characterized by that the clamping element (21) together with the seal carrier (20) is displaced axially along the central axis (M) and relative to the outer tubular tour part (1) into a locking position in which the clamping element (21) is brought into locking engagement with the outer tubular tour part (1), and the clamping element (21), while maintaining the engagement with the outer tubular tour part (1), is further displaced axially from the locking position relative to the seal carrier (20) in order to apply the pretensioning force to the seal carrier (20). [17] Method according to claim 16, characterized bythat both a locking of the clamping element (21) on the outer tubular part (1), in particular a screw connection provided for this purpose, and a release of this locking takes place without external tensile and compressive forces on connecting areas (12, 21A) provided for this purpose. [18] Method according to one of claims 15 to 17, characterized by that a tube tour arrangement according to one of claims 1 to 14 is used.

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