BR102021000190A2 - COUPLING, AND, PROCESS TO PRODUCE A COUPLING - Google Patents

Abstract

coupling, and, process for producing a coupling. a pipe-to-tube type pipeline pipe coupling (3) formed of a set of sections (1, 2) each incorporating an inner tube (2a, 2b) and an outer tube (4a, 4b) butt welded to the inner tube (2a, 2b), two successive sections (1, 2) being joined together by welding respective inner tubes (2a, 2b) delimiting a segment (5) of inner tube, in which it is formed by a sleeve (7) arranged perpendicularly to the segment (5) and a filling material (8) consisting of a fast curing mortar based on aluminous cement and sand, said filling material (8) being arranged in the free space delimited by the glove (7), by said segment (5) and by the outer tubes (4a, 4b) of two successive sections (1, 2).

Description

COUPLING, AND, PROCESS TO PRODUCE A COUPLING FUNDAMENTALS OF THE INVENTION field of invention

[001] The technical scope of the present invention is that of couplings for pipe-to-tube type pipeline joints. These pipelines are formed from sections assembled together by welding on an offshore vessel.

Description of the related technique

[002] In the petroleum industry, tube-in-tube type piping has been used for several decades to ensure the thermal insulation of pipelines formed by successive assembling by welding tube-in-tube piping sections between 6 meters and 50 meters in length. Each section consists of an inner tube and an outer tube concentric and thermal insulation in the annular zone formed by these two tubes.

[003] At each end, the outer tube is deformed into a cone shape to seal the annular zone hermetically by welding the outer tube to the inner tube. The inner tube is slightly longer than the outer tube.

[004] These sections are assembled one after the other by welding on a raft to launch pipes off the coast to form long pipelines, usually between 0.5 km and 50 km. The weld made on the raft is a butt weld between the two inner tubes of two successive sections. After this welding, the joint between the two sections is formed only by the bare single-lined inner tube.

[005] To stiffen this connection, a thermally insulated sleeve is slipped and centered over the single jacket tube joint comprising the weld and covers the outer tube on each side for a length of 1 to 3 times the diameter of the tube-type pipe in tube to ensure sufficient bending moment transfer efficiency. This sleeve is a double-lined tube with thermal insulation in the annular area. The length of the sleeve is typically 1.8 to 3 m and its inner diameter is larger than the outer diameter of the outer tube to allow for installation.

[006] To ensure that the sleeve is held in position over the pipeline, a hardenable filler material is poured or injected in a known manner to fill the volume of the junction between the inner and outer tubes of the main pipeline and the inner tube of the sleeve (typical volume between 20 to 50 litres). The filling operation for the hardenable material is carried out on the tube-launching raft.

[007] This hardenable material is usually a polyurethane resin. Thermal performance at the junction between two sections is ensured by the insulated sleeve. The sleeve coupled with the hardenable material filling the interstitial volume also provides a mechanical function which is that of reinforcing the single-lined piping section. Without this sleeve the joints between two successive sections of tube-in-tube pipe would be weak points in the pipeline from a mechanical perspective and would not be able to withstand the mechanical stresses they are subjected to during launching and other modes of pipeline operation once in place on the seabed.

[008] The mechanical efficiency of the junction is classically evaluated by the Voltage Transmission Factor (STF). This is the ratio between the bending stresses (axial stresses) of the inner tube at the middle of the joint and the inner tube at the middle of the tube-to-tube section of the pipeline. The lower the STF, the more efficient the join.

[009] The technical advantages of the joint described above allow pipeline installers to obtain considerable cost savings as the laying of this pipeline requires only one weld per section of tube-in-tube type.

[0010] During off-shore launching operations, the duration of each operation is critical as the daily cost of the pipe launching raft is extremely high, typically between EUR 200,000.00 and EUR 1,000,000 per day. Each time saved in successive operations is a saving that makes the solution more competitive. The fact that a joining solution that requires only one weld can be proposed, saves time and cuts the technical risk of welding in half for operators of off-shore launch rafts. Once the two inner tubes have been welded together and the probe inspected and protected, complete sleeve installation via semi-shells can be accomplished quickly, typically in less than 10 minutes.

[0011] A current limitation of this method of joining is the resistance to high temperatures. In fact, the hardenable materials used today, of the polyurethane resin type, cannot withstand temperatures in excess of 100°C in a marine environment (pressurized water) or even 80°C depending on the planned duration of the charge (typically 10 to 20 years). Aging tests carried out in autoclaves show that the mechanical properties of a polyurethane resin deteriorate at temperatures above 100°C, or even 80°C.

[0012] Another material used is di-polycyclopentadiene (DPCD) which is temperature resistant up to 180°C. However, this DPCD shows significant thermal and chemical shrinkage of several percentage points by volume during hardening. This contraction means that this material does not allow good transmission of mechanical forces between the two successive sections and the sleeve.

[0013] Furthermore, this contraction is made worse by poor adhesion of DPCD to the glove walls, the inner tube and the outer tube of the pipeline.

[0014] The play created by this contraction is greater in the central part of the coupling of the joint, since that is where there is the greatest thickness of hardenable material, between around 20 and 50 mm. In this part, the contraction can reach 1 to 4 mm.

[0015] This of course means that the mechanical stresses to which the inner pipe of the pipeline is subjected will not be efficiently transmitted to the sleeve, which in the worst cases may move vertically under its own weight or generally slide along the pipeline.

[0016] This results in a reduction in the service life of the pipeline with respect to mechanical fatigue, since this type of pipeline is subjected to mechanical stresses both during off-shore launch and throughout the entire operational functioning of the pipeline.

SUMMARY OF THE INVENTION

[0017] The aim of the invention is to propose a coupling for joining sections of pipeline that does not suffer from these drawbacks.

[0018] The invention thus relates to a pipe-to-tube type pipeline pipe coupling formed of a set of sections each incorporating an inner tube and an outer tube welded from the top to the inner tube, two successive sections being joined together by welding of respective inner tubes delimiting a segment of inner tube, in which it is formed by a sleeve arranged perpendicularly to the weld and a filling material consisting of a fast curing mortar based on aluminous cement and sand, said filling material being arranged in the free space delimited by the sleeve, the said segment and the outer tubes of two successive sections.

• - 30 a 49% de cimento aluminoso
• - 40 a 58% de areia de diorito,
• - 0,6 a 1% de superplastificante,
• - 0,5 a 1% de acelerador de cura, e
• - ajuste a 100% usando água.

[0019] According to a characteristic of the coupling according to the invention, the filler material has the following bulk composition:

• - 30 to 49% aluminous cement
• - 40 to 58% diorite sand,
• - 0.6 to 1% of superplasticizer,
• - 0.5 to 1% of cure accelerator, and
• - adjust to 100% using water.

• - 33% de cimento aluminoso
• - 55% de areia de diorito,
• - 0,7% de superplastificante,
• - 0,6% de acelerador de cura, e
• - ajuste a 100% usando água.

[0020] Advantageously, the filler material has the following bulk composition:

• - 33% aluminous cement
• - 55% diorite sand,
• - 0.7% superplasticizer,
• - 0.6% cure accelerator, and
• - adjust to 100% using water.

• - 39% de cimento aluminoso
• - 50% de areia de diorito,
• - 0,7% de superplastificante,
• - 0.6% de acelerador de cura, e
• - ajuste a 100% usando água.

[0021] Advantageously again, the filler material has the following bulk composition:

• - 39% aluminous cement
• - 50% diorite sand,
• - 0.7% superplasticizer,
• - 0.6% cure accelerator, and
• - adjust to 100% using water.

• - 44% de cimento aluminoso
• - 45% de areia de diorito,
• - 0,8% de superplastificante,
• - 0,6% de acelerador de cura, e
• - ajuste a 100% usando água.

[0022] Advantageously again, the filler material has the following bulk composition:

• - 44% aluminous cement
• - 45% diorite sand,
• - 0.8% superplasticizer,
• - 0.6% cure accelerator, and
• - adjust to 100% using water.

• - 47% de cimento aluminoso
• - 41% de areia de diorito,
• - 1% de superplastificante,
• - 0,9% de acelerador de cura, e
• - ajuste a 100% usando água.

[0023] Advantageously again, the filler material has the following bulk composition:

• - 47% aluminous cement
• - 41% diorite sand,
• - 1% superplasticizer,
• - 0.9% cure accelerator, and
• - adjust to 100% using water.

[0024] The invention also relates to a process for producing a coupling in which two tube-to-tube pipeline sections are joined, and then the inner tubes are welded together, in which a sleeve is positioned perpendicular to the weld of the inner tubes and the filling material is injected.

[0025] An advantage of the present invention resides in the aging resistance of the filler material at temperatures up to 180°C and its curing time of less than 10 min.

[0026] Another advantage of this mortar is that it does not shrink during curing.

[0027] Yet another advantage of this material lies in the fact that the modulus of elasticity in compression of the mortar remains relatively constant in the temperature range of this application. The modulus of elasticity is high, for example between 20,000 MPa and 35,000 MPa.

[0028] Yet another advantage of this filler material lies in the fact that mortar is a material with a coefficient of thermal expansion similar to that of steel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, advantages and particularities of the invention will become evident from the additional description given here below with reference to the drawings, in which:
[Fig 1] shows a cross-sectional view of two pipeline sections assembled together,
[Fig 2] is a longitudinal sectional view of the joint coupling according to the invention of a joint of a pipe-to-tube type pipeline,
[Fig 3] is a cross-sectional view of the joint coupling according to the invention,
[Fig 4] is another cross-section of the joining coupling according to the invention.

DETAILED DESCRIPTION OF MODALITIES OF THE INVENTION

[0030] The invention will now be described in greater detail. As previously indicated a tube-in-tube pipeline is formed of several sections joined together to produce lengths of a few hundred to a few thousand meters. The problem is to couple these different sections together and consolidate the join between successive sections.

[0031] Figure 1 shows two sections 1 and 2 of tube-in-tube pipelines equipped with a coupling 3. Needless to say, the pipeline is made up of a large number of sections, as per the customer's wishes. Each section 1 or 2 comprises an inner tube 2a, 2b and an outer tube 4a, 4b between which the annular zone thus delimited is filled with thermal insulation, not shown.

[0032] Figure 2 shows a longitudinal sectional view of the coupling 3 where the inner tubes 2a, 2b and the outer tubes 4a, 4b can be seen. Each outer tube is classically butt welded onto the inner tubes after their ends have been flanged as seen in the figure. Inner tubes 2a and 2b were welded together delimiting a segment 5 with a single inner tube.

[0033] As explained above, this segment is reinforced by means of a coupling 6 according to the invention which is constituted by a sleeve 7 positioned perpendicularly to the segment 5 and a filling material 8. The sleeve 7 is in the form of a tube with double coating. The filling material 8 is arranged in the free space delimited by the sleeve 7, by said segment 5 and by the outer tubes 4a and 4b of the two successive sections 1 and 2.

[0034] This filling material 8 consists of a mortar based on aluminous cement and fast curing sand whose composition will be explained below.

[0035] In figure 3, which is the axial section along AA in figure 2, the inner tube 2a is shown, with the filling material 8 and the sleeve 7 formed by its inner tube 9 and outer tube 10 separated by a thermal insulation 11. The filling material 8 can be seen as completely occupying the free space available between the segment 5 and the sleeve 7.

[0036] Figure 4, which is an axial sectional view along BB in Figure 2, shows the inner tube 2b, the outer tube 4b, the filling material 8 and the inner tube 9 of the sleeve 7.

• - 30 a 49% de cimento aluminoso
• - 40 a 58% de areia de diorito,
• - 0,6 a 1% de superplastificante,
• - 0,5 a 1% de acelerador de cura, e
• - ajuste a 100% usando água.

[0037] According to the invention, the filling material 8 is constituted by an aluminous-based cement with the following mass composition:

• - 30 to 49% aluminous cement
• - 40 to 58% diorite sand,
• - 0.6 to 1% of superplasticizer,
• - 0.5 to 1% of cure accelerator, and
• - adjust to 100% using water.

[0038] A person skilled in the art may, depending on technical requirements, determine the composition to be adopted by choosing the appropriate percentage.

[0039] Thus, the following compositions can be used:

EXAMPLE 1

• - 33% de cimento aluminoso
• - 55% de areia de diorito,
• - 0,7% de superplastificante,
• - 0,6% de acelerador de cura, e
• - ajuste a 100% usando água.

[0040]

• - 33% aluminous cement
• - 55% diorite sand,
• - 0.7% superplasticizer,
• - 0.6% cure accelerator, and
• - adjust to 100% using water.

EXAMPLE 2

• - 39% de cimento aluminoso
• - 50% de areia de diorito,
• - 0,7% de superplastificante,
• - 0,6% de acelerador de cura, e
• - ajuste a 100% usando água.

[0041]

• - 39% aluminous cement
• - 50% diorite sand,
• - 0.7% superplasticizer,
• - 0.6% cure accelerator, and
• - adjust to 100% using water.

EXAMPLE 3

• - 44% de cimento aluminoso
• - 45% de areia de diorito,
• - 0,8% de superplastificante,
• - 0,6% de acelerador de cura, e
• - ajuste a 100% usando água.

[0042]

• - 44% aluminous cement
• - 45% diorite sand,
• - 0.8% superplasticizer,
• - 0.6% cure accelerator, and
• - adjust to 100% using water.

EXAMPLE 4

• - 47% de cimento aluminoso
• - 41% de areia de diorito,
• - 1% de superplastificante,
• - 0,9% de acelerador de cura, e
• - ajuste a 100% usando água.

[0043]

• - 47% aluminous cement
• - 41% diorite sand,
• - 1% superplasticizer,
• - 0.9% cure accelerator, and
• - adjust to 100% using water.

[0044] The above mortar compositions can be produced in the following manner.

[0045] First, an intimate mixture of aluminous cement and diorite sand is made, the superplasticizer is then added followed by water. The intimate mixture thus obtained can be kept soft as long as the curing accelerator is not added. When coupling is to be done, the accelerator is added to the mortar and mixed into it and the resulting mixture must be used very quickly.

[0046] To make the coupling 3, the inner tubes 2a and 2b are welded together, then the sleeve is placed perpendicular to the segment 5 covering the outer tubes, respectively 4a and 4b, then the mortar is quickly poured or injected into the delimited free space by sleeve 7, by segment 5 and by outer tubes 4a and 4b.

• • Tempo de cura: <10 min; quanto mais curto este tempo mais economicamente competitiva a solução. Com um tempo de pré-mistura longo, o tempo de cura pode ficar entre 3 e 5 minutos, depois que o acelerador tenha sido adicionado.

[0047] For a filling material intended for temperatures up to 180°C, the properties of this mortar are excellent, namely:

• • Curing time: <10 min; the shorter this time, the more economically competitive the solution. With a long premix time, the cure time can be between 3 and 5 minutes after the accelerator has been added.

• ⚪ >10 MPa quando fresca,
• ⚪ > 60MPa quando madura;

• Maneabilidade: A argamassa pode ser despejada ou injetada entre dois tubos concêntricos com espaço anular de entre 5 e 10 mm no raio ou mais, normalmente até 80 mm;
• Nenhuma contração por cura
• Resistência ao envelhecimento em um ambiente marinho sob uma pressão de 100 bars, ou mesmo até 220.105 Pa, a uma temperatura de 140°C ou mesmo até 180°C.[0048]
• Compressive strength:

• ⚪ >10 MPa when fresh,
• ⚪ > 60MPa when ripe;

• Handling: The mortar can be poured or injected between two concentric tubes with an annular space of between 5 and 10 mm in radius or more, normally up to 80 mm;
• No contractions per cure
• Resistance to aging in a marine environment under a pressure of 100 bar, or even up to 220,105 Pa, at a temperature of 140°C or even up to 180°C.

• • Módulo de elasticidade em compressão: entre 20.000 MPa e 35.000 MPa;
• • Módulo de elasticidade em flexão: entre 6.000 e 15.000 MPa;
• • Resistência a tensão mecânica cíclica: nenhuma deterioração da argamassa entre 2 tubos quando os tubos são ciclicamente tensionados por um grande número de ciclos, por flexão por exemplo.

[0049]

• • Modulus of elasticity in compression: between 20,000 MPa and 35,000 MPa;
• • Modulus of elasticity in bending: between 6,000 and 15,000 MPa;
• • Cyclic mechanical stress resistance: no deterioration of the mortar between 2 tubes when the tubes are cyclically tensioned for a large number of cycles, by bending for example.

[0050] Typical tube-in-tube type piping diameters are 170 mm and 220 mm, respectively for the inner tube 2a or 2b and the outer tube 4a or 4b for the smallest, and can reach 400 mm and 500 mm, respectively for the tube inner 2a and 2b and outer tube 4a and 4b for the largest installed sizes. The tube diameters of the double jacketed sleeve 7 are larger than the outer tube diameter 4a and 4b of the tubing to enable the sleeve to be positioned over the weld.

[0051] A typical clearance between the outer pipe tube and the inner tube of the sleeve is between 5 mm and 15 mm in the thin parts and the typical clearance between the inner pipe of the pipe and the inner tube of the sleeve is between 25 mm and 80 mm in the central part. It is this space that is filled with mortar according to the invention

[0052] The advantage of this mortar is its resistance to aging at temperatures of up to 180°C and its curing time of less than 10 min which makes it suitable for use as a filling material for coupling 7 of pipelines outside the during the launch of such pipelines by off-shore ferries and for operating temperatures of up to 180°C.

[0053] Another advantage of this mortar is that it can be used for S launch or J launch installation modes as it requires a single pour or inject operation to fill the gap between the sleeve and pipeline at the junction and once the sleeve is in position over the weld joining the two sections of pipeline.

[0054] Another advantage of this mortar is that it does not shrink when curing between 2 concentric tubes and with play in the range of 5 mm to 15 mm in the fins or 25 mm to 80 mm in the central part of the joint.

[0055] Another advantage of this joint configuration is the improved mechanical efficiency of joining these two sections of tube to tube with the sleeve. In fact, the mechanical properties of such a mortar are greater than those of other hardenable materials such as polyurethane resin or di-polycyclopentadiene (DPCD). The compression modulus of this mortar is in the range of 28,000 MPa whereas it is in the range of 2,000 MPa for a polyurethane resin or DPCD at room temperature. The high modulus of elasticity of the mortar allows for better transmission of mechanical stresses between the pipeline and the sleeve at the junction.

[0056] With identical dimensions, the joint using this mortar as a filler material 8 will have better bending stiffness than the same joint using a resin or DPCD as a filler material. In this configuration, this improved transmission of mechanical stresses between the pipeline and the sleeve enables a reduction of mechanical stresses in the single-wall section of the pipeline thereby improving its flexural strength and fatigue life.

[0057] Another advantage of this configuration is that the modulus of elasticity in compression of the mortar remains relatively constant over the temperature range of this application, whereas this modulus is reduced when the temperature increases in a polyurethane resin or DPCD. The mechanical efficiency of the junction is thus relatively constant over the operating temperature range of this application.

[0058] Another advantage of this configuration is that, thanks to the superior modulus of elasticity in compression of this mortar with respect to PU resin, for example, the geometry of the double-coated sleeve (diameter and thickness of tubes, length) can be optimized . In fact, the flexural stiffness of the coupling depends mainly on the length of the sleeve 7, the flexural stiffness of the sleeve 7 and the modulus of elasticity in compression of the filler material 8. Since the mortar has a modulus of elasticity in compression more than 10 times larger than that of a PU resin or a DPCD, sleeve 7 can be selected shorter and/or with a lower flexural stiffness (= thinner tube thicknesses) while ensuring the same flexural stiffness of the joint.

[0059] As the thermally insulated double-lined sleeve 7 also plays a role in reducing thermal losses from the single-lined section of the pipeline, a balance will need to be checked so that the sleeve geometry ensures both a bending stiffness and a joint thermal performance in line with pipeline specifications.

[0060] Another advantage of this filler material 8 is that this mortar is a material with a coefficient of thermal expansion in the range of 12.10-6 m/(m.K). This coefficient of thermal expansion is similar to the coefficient of thermal expansion of the steels used for pipelines and the double-lined sleeve. This allows the thermal stresses operating between the steel tube and the joint fill material to be limited. In fact, in operation, the inner tube of the pipeline will be at a temperature of 100°C or even up to 180°C, the average junction temperature will increase and thermal stresses may appear due to differences in thermal expansion between the steels in the pipeline and the filling material. This will not be the case for this setup using this mortar.

[0061] Another advantage of this configuration is that the inner tube of the sleeve can be deformed by a few millimeters (from 2 to 10 mm for example) inwards at one or several places along its length to improve the sliding resistance of the glove by geometric impediment.

Claims (7)

Coupling (3) for pipe-in-tube type pipeline piping, characterized in that it is formed by a set of sections (1, 2) each incorporating an inner tube (2a, 2b) and an outer tube (4a, 4b) welded top on the inner tube (2a, 2b), two successive sections (1, 2) being joined together by welding respective inner tubes (2a, 2b) delimiting a segment (5) of inner tube, wherein said coupling is formed by a sleeve (7) arranged perpendicularly to said segment (5) and a filling material (8) consisting of a fast curing mortar based on aluminous cement and sand, said filling material (8) being arranged in the space free bounded by said sleeve (7), said segment (5) and said outer tubes (4a, 4b) of said two successive sections (1,2). Coupling (3) for a tube-in-tube type pipeline according to claim 1, characterized in that said filling material has the following mass composition:

• - 30 to 49% aluminous cement
• - 40 to 58% diorite sand,
• - 0.6 to 1% of superplasticizer,
• - 0.5 to 1% of cure accelerator, and
• - adjust to 100% using water.

Coupling (3) for a tube-in-tube type pipeline according to claim 2, characterized in that said filling material has the following mass composition:

• - 33% aluminous cement
• - 55% diorite sand,
• - 0.7% superplasticizer,
• - 0.6% cure accelerator, and
• - adjust to 100% using water.

Coupling (3) for a tube-in-tube type pipeline according to claim 2, characterized in that said filling material has the following mass composition:

• - 39% aluminous cement
• - 50% diorite sand,
• - 0.7% superplasticizer,
• - 0.6% cure accelerator, and
• - adjust to 100% using water.

Coupling (3) for a tube-in-tube type pipeline according to claim 2, characterized in that said filling material has the following mass composition:

• - 44% aluminous cement
• - 45% diorite sand,
• - 0.8% superplasticizer,
• - 0.6% cure accelerator, and
• - adjust to 100% using water.

Coupling (3) for a tube-in-tube type pipeline according to claim 2, characterized in that said filling material has the following mass composition:

• - 47% aluminous cement
• - 41% diorite sand,
• - 1% superplasticizer,
• - 0.9% cure accelerator, and
• - adjust to 100% using water.

Process for producing a coupling (3) as defined in any one of the preceding claims, characterized in that said two sections (1, 2) of pipe-in-tube type pipeline are joined and then said inner pipes are welded together, in that a sleeve (7) is positioned perpendicularly to the segment (5) of said inner tubes (2a, 2b) and said filling material (8) as defined in any one of the preceding claims is injected.

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