Tubular component connection protector

Description [0001] The invention relates to threaded tubular elements, and more specifically to end protectors of some of these elements, in particular oil pipes or oil or gas well wells.

[0002] In this case, the term "element" means any element or accessory used for drilling or operating a shaft and comprising at least one connection or joint or threaded end and intended to be connected by threading to another element to form with that other threaded element pipe fitting. The element may be, for example, a relatively long length tubular element (in particular, about ten meters long), e.g. a pipe or sleeve a few dozen centimeters long, or an accessory for these tubular elements (suspension device or "hanger, part for changing the cross-section or "cross-over", safety valve, drill pipe connection or "tool joint", "sub" and the like).

[0003] The components are generally mounted together to lower into hydrocarbon shafts or similar shafts and form a drill string, casing column ("casing") or lost pipe ("liners or column of production pipes (" tubing ") .

[0004] The API 5CT specification issued by the American Petroleum Institute (API), equivalent to the ISO 11960: 2004 standard issued by the International Organization for Standardization (ISO), regulates pipes used as casing or tubing, while the API 5B specification specifies the standard threading for these pipes.

[0005] The API 7 specification defines a threaded coupling for rotary drilling rods.

[0006] Manufacturers of threaded elements of pipe fittings have also developed so-called master fittings ("premiumj" which have special threading geometry and special means to ensure better performance in use, in particular in terms of mechanical strength and tightness.

[0007] Threaded connections most often include one or two threads whose threads are essentially trapezoidal and include a coupling side on the thread side facing the free end of the threaded element under consideration, a support side on the opposite side of the coupling threads, a thread tip with a non-zero width, and a thread underside with a non-zero width, wherein the support sides and the coupling sides are oriented substantially perpendicular to the axis of the threaded element (For example, the API Buttress thread has, according to the API standard, a slope of + 3 ° for the supporting sides and a slope of + 10 ° for the coupling sides).

[0008] There are also triangular or round threads, which also have coupling sides and load-bearing sides, whose tops and bottom of the threads have essentially zero width, but which are now very rarely used because they pose a high risk of disconnection ("jump-out").

[0009] The above-mentioned elements may comprise a threaded male end, which is intended to be screwed to the threaded female end of another element for drilling or operation. It is therefore important that their male and female ends be as damaged, contaminated and degraded as little as possible from the moment they leave the production line to the point where they are used, but also between two successive uses. It should be understood that in fact it is necessary to protect against corrosion, dust and shocks (or impacts) not only on threads, but also possible bearings and couplings, each of which has specific and complementary functions, in particular to ensure tightness during use.

[0010] Furthermore, the ends of the above-mentioned elements were generally coated just before assembly with anti-seizing lubricating oil.

[0011] It is becoming increasingly common to replace this lubricating oil with a combination of surface treatment and coatings arranged in thin layers at the joints, i.e. on the thread, on the bearing and / or on the coupling. [0012] For example, in particular in US 6,027,145, EP 1211451 and FR it has been proposed 2892174, replacement of lubricating oil applied at the end with a brush at the end of the element with a thin layer of a predetermined thickness applied at the factory, a dry grease based on solid grease particles. Documents FR 2979968 and US Re. 30,647 also describe threaded fasteners.

[0013] These surface treatments and coatings exhibit hardness, lubricity, anti-corrosion properties adapted to the practical situation of mounting two joints or assembled, and it is necessary to adapt the joint protectors outside these stages of product life, in particular during storage, handling and transport, in order to maintaining the joint against both mechanical displacement and contamination (sand, debris) harmful to the effectiveness of the product.

[0014] These coatings are also called lubricating coatings and are classified as solid or semi-solid, dry or semi-dry. They have viscous properties, covering a very wide range, from 500 mPa.s at 25 ° C to over 5000 mPa s at 25 ° C, some are even referred to as "sticky", that is, when applied to the surfaces of the joint, they can stick to the object who touches them, in particular, can be carried on the fingers of the operator who touches the coated surface of the joint. Others, on the contrary, are classified as stiff and have a certain hardness. These are sought after properties to facilitate the installation of two connections, but are problematic for connection protectors. In fact, they must protect the joints from shocks, they must be firmly attached to the joints and they must have rigid bodies.

[0015] Protectors are devices whose function is to protect the functional surfaces of male or female connections: These functional surfaces may have one or more threadings, one or more bearings, one or more couplings. The protector is generally cylindrical and generally contains a mechanical shock absorber called a bumper, located at the end opposite the free end of the protector, body, and mounting means. The solution generally adopted to attach the protector to the connection is to screw it to thread the connection. This solution allows for simple assembly combined with precise positioning. Therefore, the protector has threading that can be screwed to thread the connection. The threading is usually of the same type and with the same pitch as for the connection. The threading of the protector thus consists of threads with coupling sides on the thread side oriented towards the free end of the protector and is intended to come into contact with the coupling sides of the connection threads when screwing the protector to the connection, bearing sides, vertices and thread bottoms.

[0016] In addition, with the appearance of surface treatments and coatings placed at the joints, the protectors were provided with sealing means to increase the moisture tightness or air tightness of the space around the surface, including the functional surfaces of the joint.

[0017] The applicant has found, however, that during transport or handling of the pipes on which known protectors are mounted, the functional surfaces of the joints are insufficiently protected against damage, in particular mechanical shocks. It happens that the known protectors unscrew partially or completely or that the functional surfaces are damaged despite the presence of the known protectors mounted on the joint.

[0018] US20100038904 proposes a female connection protector comprising threading, whose threads have a thread height greater than the height of the connection thread. Also the base thread of the protector's threading includes a coupling side intended to contact the engagement side of the thread of the primary female connection and for which the angle of the coupling side of the thread of the protector differs from the angle of the coupling side of the connection thread. These two features allow, on the one hand, to avoid, due to the difference in thread height, contact between the underside of the protector thread and the top of the connection thread, thereby limiting the deterioration of the coating on the tops of the connection threading threads, and on the other hand, by reducing the angle between the corresponding sides, reduce contact surface between the coupling sides. This allows the coating to retain parts of the surface of the sides engaging the connections. However, this solution is not entirely satisfactory because the forces exerted between the coupling side of the thread of the protector and the coupling side of the connection thread are concentrated on part of the coupling side of the threading connection and make this area more exposed to possible damage to the coating.

[0019] WO2011 / 140014 proposes a protector whose threads have a much higher pitch in relation to the connection threads, such that the connection threads intersect the threads of the protector and the connection threads drill the material of the threads of the protector. This allows production savings to be achieved thanks to standardized protectors, compared to connections that can have different types of threading. But this solution is not suitable for connections with coated threads. Indeed, the threads of the connection cut the protector's thread material, generating chips. The walls of the recesses formed in the thread material of the protector and chips will tend to scrape the sides of the connection threads, their tops or bottoms, and to remove lubricating oil or coating from the surface of said connection threads.

[0020] At another level, the applicant proposed in EP2126449 a protector with elastic sealing means which have a first and second orientation in the free state and have a third and fourth orientation when the protector is screwed in the end position. This solution allows the storage of anti-twist energy in sealants.

However, the function of maintaining the joint coating is unsatisfactory, functional surfaces may still deteriorate when the protector is subjected to mechanical shocks.

[0021] The object of the invention is to improve the situation by maintaining the joint coating attached thereto, whether during screwing / unscrewing the joint protector or under mechanical and / or thermal stress to which the protectors and tubular elements are exposed.

[0022] To this end, the invention is a tubular element with a male or female end of a drill protector or hydrocarbon well operation, wherein the male or female end is provided with at least one external threading or internal threading of the outer annular surface and the inner annular surface separated respectively at least one threading, wherein the protector includes at least one threading comprising at least a first threaded part comprising at least one thread with a pitch P1 cooperating by screwing with male threading or female threading, and the protector includes a second threading part comprising at least one thread with a pitch P2 other than P1, which allows you to generate additional torque when tightening the protector on the connection.

[0023] According to one embodiment, the pitch P2 is such that the value P2 corresponds to the following equation: P2 = Pl + AxPl avec A> 0 [0024] According to one embodiment, the pitch P2 is such that the value P2 is according to the following equation: P2 = PI - A x PI avec A> 0 This allows the distribution of the torsional torque of the supporting sides or the sides of the coupling threads with a pitch of P2 with the supporting sides or coupling threads of the connection, respectively.

[0025] According to one embodiment, the external (4) or internal (17; 26; 25) threading of the connection has a WTC gap separating the two threads of the external (4) or internal (17; 26) connection. and the value of coefficient A is such that: 0 <A <WTC / P1 This allows limiting the contact pressure from the sides with a pitch P1 with the sides of the threads of the connection threading.

[0026] According to one embodiment, each thread with pitch P1 has a thread width TW1 that external (4; 25) or internal (17; 26) the connection has a WTC distance separating the two threads of the connection threading, and in this case the value of the coefficient A is strictly greater than 0 and less than the value of Amax determined on the basis of the following equation: Amax = (WTC - TW1) / PI This allows further contact pressure of the sides threads with pitch P1 with the sides of the threads threading the connection.

[0027] According to one embodiment, the A value is greater than 0.2. [0028] According to one embodiment, A is between 0.05 and 0.8.

[0029] According to one embodiment, the second threaded portion (39) comprises from 1 to 3 threads with P2 pitch, and the first threaded portion (38) contains from 2 to 5 threads with P1 pitch, which allows the contact surfaces between the threads of the protector to be limited with connection threads and limiting the possible degradation of these connection threads.

[0030] According to one embodiment, the protector is a female end protector and the second threaded portion (39) is placed on the protector body in front of the first threaded portion (38), which allows an effect on the tightening torque when the protector is already partially screwed to connect.

[0031] According to one embodiment, at least one thread of the other threaded portion (39) is adapted to contact at least one incomplete thread of the external (4; 25) or internal (26) threading of the pipe fitting element when the protector is in the bolted condition at the end of the pipe fitting element, which allows the threads of so-called perfect threading of the connection to be retained.

[0032] According to one embodiment, the protector comprises a main body (20), an inner seal (32) and an outer seal (33) adapted to form a first and second seal with respectively inner (5; 28) and outer (27) annular surfaces male (3) or female (2) endings, which allows creating a closed zone around the functional surfaces of the connection.

[0033] According to one embodiment, at least one of the seals, internal (32) or external (33), is flexible, which allows energy to be generated to prevent unscrewing of the protector when it is screwed to the joint.

[0034] According to one embodiment, the elastic seal is an elastic annular collar, which allows energy to be obtained to prevent unscrewing.

[0035] According to one embodiment, both seals are flexible and are elastic annular flanges, which significantly increases energy against loosening.

[0036] According to one embodiment, the protector comprises a second internal or external threading and a third threaded portion comprising at least one thread with a pitch P3 other than P2 and other than P1, which increases energy against unscrewing.

[0037] The pipe element for drilling and operation of the oil or gas wells generally consists of a body and two connections on both sides of the body to connect the pipe element with other pipe elements. The element can be made of steel, stainless steel and / or aluminum.

[0038] In particular, the pipe comprises a body and one connection at each end on both sides of the body. The connection may be part of the body end with the machined surfaces to form a connector with the connection corresponding to another tubular body. Alternatively, the connection may be a machined part of the sleeve attached by welding or screwing to the tubular body. Alternatively, the connection may be a sleeve welded to the body of the tubular element.

[0039] The term "male connection" means the part of the element provided with the machined and / or ground surfaces to form a connector with a corresponding female connection. The male connection generally has one or more threads located on the outer side wall of the element end, and the corresponding female connection has one or more corresponding threads on the inner side wall of the element end.

[0040] The element may be equipped with two male connections, one male connection and one female connection or two female connections.

[0041] The protector is primarily intended to protect the connection of the tubular element (intended for drilling or operating hydrocarbon wells or similar) against various types of external threats: mechanical damage, such as mechanical shocks, impurities (chemical and material), such as dust depositing on functional surfaces and corrosion of materials between the moment the tube element leaves the production line and the moment of its use (with several possible assembly and assembly of the safety device).

[0042] The protector according to the invention allows quick and reliable assembly and disassembly of the protector at the connection of the tubular element and allows easy inspection of the threading condition before use or between two successive uses of the element. The protector according to the invention avoids the use of additional products during assembly.

[0043] The protector according to the invention allows the surface or coating of the functional surfaces of the tubular connection to be maintained during assembly / disassembly on site or in the factory by limiting the mechanical stress exerted by the protector components on the connection surfaces, e.g.

[0044] Other features and advantages of the invention will become apparent after examining the following detailed description and attached drawings, in which:

• Figure 1 schematically illustrates a cross section of the end of a tubular element with a sleeve.

• Figure 2 schematically illustrates a cross section of two assembled ends of a tubular element.

• Figure 3 schematically illustrates a partial cross-section of a method of making a male connection protector according to the invention.

• Figure 4 schematically illustrates a partial cross section of a female connection protector according to an embodiment of the protector according to the invention.

Figure 5 schematically illustrates the trapezoidal profile of the threading of the female connection protector and the threading of the female connection.

• Figure 6 is a detailed view of figure 4 in cross-section of a threading portion of the protector in accordance with one embodiment of the invention and connection.

[0045] The attached drawings may not only serve to complete the invention, but also contribute to its defined, as appropriate. They are not limiting on the scope of the invention.

[0046] The female end (2) of Figure 1 comprises a tubular body (1) comprising a threaded portion (11) and a sleeve (12) comprising a first internal threading (15) to be screwed onto the threaded portion (11) of the pipe body, female connection ( 16) comprising a second internal thread (17), intended to be screwed to the male connection of another tubular element. The connection of figure 1 is of the "threaded & Coupled" or "T&C" type in which the sleeve is attached to the pipe.

[0047] Internal threading (17) and threading of the corresponding male connection may include perfect threads and disappearing or incomplete threads.

[0048] The female connection (16) also includes a sealing surface (7) before threading, a coupling surface (8) before the second internal threading (17) and an outer annular surface of the end (6) including an end coupling (6b) after the second internal threading (17) ).

[0049] The protector according to the invention may be used to connect a male or female threaded pipe fitting, for example of the T&C type, and which may include, for example, the following elements individually or in combination:

• conical threading with a sub-part of perfect threads surrounded by two sub-parts of disappearing threads;

• a coupling surface formed by the transverse annular surface of the free end portion of the male end;

• metal / metal sealing surface on the peripheral outer / inner surface of the free end.

[0050] The threaded connector (1) of figure 2 has an axis Xi, an opening (9) and comprises a female connection (13) and a male connection (3). The external threading (4) of the male connection (3) includes top threading (4a) and bottom threading (4b). The male connection comprises an end (5), sealing surfaces (7a, 7b, 7c) and a coupling surface (8). The internal threading (14) of the female connection includes a lower internal threading (14a) and upper internal threading (14b) corresponding to the upper (4a) and bottom (4b) external threading.

[0051] Two threads of the same male or female connection can be separated radially and / or axially, made on the same cylindrical or conical surface or on different conical or cylindrical surfaces. Both threads can be separated by a coupling surface (8) and / or at least one sealing surface (7b), or alternatively simply a cylindrical connecting surface.

[0052] When the threading is tapered, they can be divided into a sub-section called perfect threads, whose height is substantially constant, and into a sub-section called disappearing or incomplete threads, the height of which gradually decreases, and whose profile may have irregularities or imperfections to create clearance between the tops and bottom of the threads. Incomplete threads are practically not subject to any torsional forces because they do not come into contact with the thread surfaces of the coupled part.

[0053] Each of the threaded connections (4a), (4b), (14a), (14b) may comprise perfect threads and disappearing or incomplete threads.

[0054] The male connection (3) of the element ends with the inner annular surface of the end (5) with a substantially transverse orientation, which can be the free end (5a) as shown in figure 2. The female connection (13) ends with the outer annular surface of the end ( 6) substantially transverse orientation.

[0055] The male connection (3) may also include one or more axial coupling surfaces corresponding to the respective axial surfaces of the female coupling (13). These coupling surfaces may be located at the free end (5) and (6), before threading and / or between two threaded parts.

[0056] The first element of the element is located after the second element of the element when the first element is located axially closer to the free end of the element. The first element of the element is in front of the second element of the element when the first element is located axially further from the free end of the element.

[0057] The male joint (3) may also include one or more metal / metal sealing surfaces corresponding to the female joint sealing surfaces (after threading, before threading, or between two threaded parts).

[0058] The example of the pipe fitting of figure 2 relates to an integrated threaded pipe fitting that can comprise the following elements individually or in combination:

• two taper threads, each with a sub-part of perfect threads surrounded by two sub-parts of disappearing threads;

• a coupling surface formed by the annular transverse surface of the intermediate portion between the two threaded ends;

• two metal / metal sealing surfaces, one on the outer / inner peripheral surface of the free end, the other on the outer / inner peripheral surface adjacent to the tubular body.

[0059] In Figure 3, the protector (10) has a substantially cylindrical axis X2, which substantially coincides with the axis Xi of the connection when the protector is in the end position bolted to the connection, and includes a body (20), a bumper (23), internal a sealing device (32) and an external sealing device (33) cooperating with the surfaces of the male connection (3) of the tubular element to form impermeable barriers. The protector (10) further includes threading (21) adapted to be screwed to the external threading (25) of the male connection (3).

[0060] The inner sealing device (32) comprises a rigid annular edge (36) in contact with the inner annular surface (5) of the free end of the connection (3). The rigid annular edge contacts the perimeter of the free end surface (5) of the connection to create a barrier to liquid, moisture and dust.

[0061] The outer sealing device (33) includes a rigid edge (34) in contact with the outer surface (51) of the periphery to form a barrier for liquid, moisture and dust.

[0062] Both sealing devices, internal (32) and external (33), thus form two barriers and allow, together with the protector body and connection, to create a liquid, moisture and dust tight zone. In particular, this sealed zone protects against corrosion of one or more of the following components considered individually or in combination: threading connections, sealing surfaces or couplings.

[0063] The body (20) has some rigidity while being able to absorb at least partly shocks. To this end, the body (20) can for example be made of a polymer material by injection of a thermoplastic material into a suitable mold. Among the various families of thermoplastic materials that can be advantageously used, polycarbonate-based mixtures such as polycarbonate-polyester (PC-PBT or PC-PET) and polyethylenes (PE) high (PE-HD) or ultra high density (PE-UHD).

[0064] In cases where compliance with the API 5CT Edition 2005 specification is required, which includes in Annex I requirements for thread protection devices, in particular minimum values ​​for axial shock resistance and deviations (45 °) for three temperatures (-46 , +21 and + 66 ° C), for example, you can in particular choose PE-HD produced by DOW and sold under the name DMBA-8904-NT7 or produced by

BASELL and sold under the name LUPOLEN 4261 AG UV 6005, PE-UHD produced by the company TICONA and sold under the name GUR 5113, or PC-PBT produced by the company

BAYER and sold under the name MAKROBLEND S7916.

[0065] It should be noted that the body may optionally be partially alveolar, in particular in thick batches, to better absorb impacts.

[0066] In figure 3, the sealing means are made of the same polymer material as the protector body and made by molding and machining directly into the protector body material. The sealing means can alternatively be attached to the body of the protector by screwing, gluing or snapping. The sealing means can alternatively be made of a softer material than the material of the protector, for example elastomer.

[0067] The body (20) also includes a radial partition (31) forming a plug and positioned in the opening (30) of the protector body. In the variant not shown, the radial partition (31) is provided with holes or even does not exist. In the embodiments shown, the radial partition (31) closes the inner space of the part below (24).

[0068] The body (20) can also be reinforced with internal or external reinforcement or integrated into the mass. An example of reinforcement is illustrated in figure 4, in the form of a metal sheath (22), to strengthen the stiffness or improve the shock resistance of the protector.

[0069] The protector (10) further includes threading of the protector (21) adapted to be screwed to thread the connection of the tubular element.

[0070] The threading of the protector (21) consists of a series of threads (70) of the type shown in figure 5. Each thread extends for a maximum of one turn, and the series of threads forms threading. The thread has a basic part which, as shown in figure 5, comprises a longitudinal part passing through the axis of rotation (X2) of the protector, thread tip (71), thread bottom (72), bearing side (74), coupling side (73) and having a thread width (TW), thread height (TH) and pitch of the coupling side. The thread pitch is the distance separating the form of the thread base and its nearest repetition found by translation on the axis cylinder generator (X2). Said cylinder is a cone when talking about conical threading.

[0071] In particular, it is possible to define for the thread an average thread pitch corresponding to the distance between two repetitions on the generator of the average thread point, which is located in the middle of the TW / 2 thread width. It is also possible to define the pitch of the thread supporting side, the pitch of the coupling thread side. The pitch of the support or coupling side corresponds to the distance between the repetition of one point of the thread height and the next point at the same thread height. The pitch of the coupling side may differ from the pitch of the supporting side. If the cross-section of the thread base does not differ in width and the pitch is constant, then the pitch of the coupling thread corresponds to the pitch of the support thread, which corresponds to the average pitch of the thread.

[0072] In the case of discontinuous or single threading, the thread pitch can be determined by measuring the offset of said thread over a revolution section, and then the thread offset can be determined at full rotation, which corresponds to the thread pitch. For example, if the thread shifts 0.2 mm in a quarter turn, then the thread offset in one turn is 0.8 mm; the thread pitch is therefore 0.8 mm.

[0073] The thread of the protector has a thread width (TW) smaller than the gap width (WTC) separating the two threads threading the joint to allow these threads to be screwed onto the joint. In addition, the thread width of the protector is most often given as a percentage of the thread width of the threading the connection. The value of this percentage is often between 50% and

90%. The thread width is measured at half the thread height.

[0074] In particular, the thread with pitch P1 has a width of TW1.

[0075] The threading (21) of the protector comprises a first threaded portion (18) comprising a plurality of threads (70) with a first pitch P1 and a second threaded portion (19) comprising at least one thread (75) with a second pitch P2 different from P1.

[0076] The second threaded portion (19) is located behind the first threaded portion.

[0077] The pitch P1 essentially corresponds to the threading pitch of the pipe connection, which makes it possible to screw the protector without difficulty to said pipe connection. The pitch P2 does not therefore correspond to the threading pitch of the pipe connection.

[0078] This difference in pitch between the pitch P1 and the pitch P2 allows the protector to be locked at the connection when screwed. Indeed, when screwing the protector to the male connection (3), in the first stage, the coupling sides of the threading thread of the protector (21) with the pitch P1 contact the coupling sides of the male connection threading. In the second stage, the second threaded portion (19) with at least one thread with pitch P2 contacts the internal threading (21,26) of the male connection. The screwing torque then increases by more than the mere addition of an additional thread side surface as a result of friction on the threading of the connection, because the threads are strained, deformed, which increases the force felt by the side of the thread of the protector and exerted by the side of the thread of the connection, thereby increasing the screwing moment of the protector on the connection.

[0079] In this way, the protector according to the invention prevents the spread of certain shocks experienced by the protector during transfer of the threads of the protector and destroys the coating of the connection. Joint coatings are better preserved.

[0080] In one embodiment, the pitch P2 is greater than the pitch P1. The bearing sides of the threads of the second threaded part (19) are in contact with the bearing sides of the threading of the pipe connection, additional contact pressure is created by threading the pipe connection on the threading of the protector. This pressure is due to the additional contact surface formed between the threads, but especially because of the stress exerted by threading the connection through the thread of the protector. This causes a sudden increase in the screwing moment of the protector when the thread (s) with the pitch (P2) engage with the threading of the pipe connection, and also causes a better holding of the protector in position, thereby increasing the screwing moment.

[0081] In one embodiment, the value of P2 is such that P2 = P1 + (A x P1). A is the coefficient of variation in the pitch. The product of the coefficient of change of pitch A in the pitch P1 represents the pitch shift. A is a non-zero real number.

[0082] In one embodiment, the coefficient A is strictly greater than 0 and smaller than the value such that the pitch offset is smaller than the WTC distance separating the two threads of the connection; coefficient A is such that: 0 <A <WTC / P1.

[0083] In another variant, the coefficient A is strictly greater than 0 and smaller than the value such that the pitch offset is smaller than the difference between the WTC distance separating the two threads of the connection and the width TW1 of the thread with pitch P1, the difference divided by pitch P1, so that:

<A <(WTC-TW1) / P1 [0084] Thus, it can be obtained, while the protector according to the invention is screwed on the joint, that the sides of the threads with pitch P1 have very low contact pressure or zero contact pressure on the sides of the threads of the connection. This definition is particularly appropriate when the pitch P2 is obtained by changing the thread width with pitch P2 in relation to the thread width with pitch P1, which then has a width TW2 different from the width TW1 of the thread with pitch P1.

[0085] In one embodiment, the factor A has a value between 0.1 and 0.8. These ranges correspond to the values ​​that allow you to achieve the desired effect in most common connection dimensions.

[0086] Preferably, the A value is greater than 0.2 irrespective of the maximum A value selected. The effect of resistance to accidental unscrewing is enhanced.

[0087] In this way, the number of threads required to be used when screwing the protector on the connection sufficient to reduce the risk of accidental unscrewing is reduced. Also, the number of thread pad surfaces that are in contact with the thread surfaces of the connection is reduced when the pad is in a bolted condition. Lubricating oils or coatings applied to thread surfaces are therefore less damaged in the event of shock.

[0088] The protection provided by the protector according to the invention in a mounted condition is also less sensitive to temperature changes. Indeed, the drilling element and oil wells can be stored in sunny regions at high temperatures or in regions with low temperatures. The protector and connection change in dimensions of different sizes, which may cause the sub-elements of the protectors and the contacts in contact with each other to move relative to each other, e.g. threaded parts of the protector relative to the threaded parts of the connection. The protector according to the invention and subjected to extreme temperatures retains the threads of the connection.

[0089] In an alternative embodiment, the threading of the protector (21) comprises a first threaded portion (18) comprising a plurality of threads with a pitch P1 of width TW1 and a second threaded portion (19) comprising at least one thread with a pitch P2 of less than P1, such that P2 = P1 - (A x P1), where the coefficient A is strictly greater than 0 and less than (WTC TW1) / P1. Alternatively, A is strictly greater than 0 and less than WTC / P1. Alternatively, A is between 0.05 and 0.8.

[0090] The coupling side with pitch P2 is shifted towards the surface of the coupling thread side of the connection relative to the side of the coupling thread with pitch P1. The contact pressure of the threads with pitch P1 on the threads of the connection is reduced, and the contact pressure between the coupling sides (73) of the threads with pitch P2 and the coupling sides (76) of the threading of the pipe connection is increased in order to obtain a substantially identical result of increasing the tightening / loosening torque. The contact pressure between the threading of the connection and the coupling sides of the threads with pitch P1 is reduced, so that the coating attached to the surface in contact with the coupling sides of threads with pitch P1 is less prone to damage.

[0091] Preference is given to the threads having a pitch P2 in contact with the so-called incomplete connection threads.

[0092] According to the invention, the female connection protector is shown bolted in figure 4. The female connection (13) comprises an inner annular surface (28), an outer annular surface (27) and internal threading (26). The female connection protector (40) includes a body (20), external threading (37), an elastic inner seal (42) and an elastic outer seal (43).

[0093] The female connection protector (40) is shown in figure 4 with the options of metal reinforcement (22) designed to improve the stiffness and shock resistance of the protector (40) and the radial septum (31) forming a plug.

[0094] The first and second, inner (42) and outer (43) seals are annular and flexible. By elasticity is meant that the seals are deformable by axial bending in order to obtain, by surface contact with the inner (28) and outer (27) annular surfaces of the connection, energy partially counteracting accidental unscrewing and maintaining contact pressure between the seal and the annular surface of the connection, to obtain and maintain a seal.

[0095] As shown in Figure 4, the inner seal (42) protrudes outward radially in the form of a collar (or tongue or lamella) intended to contact the inner annular surface (28) of the female connection (13) to ensure continuous local sealing along the entire perimeter when the protector is placed in its bolted condition in its final position. Preferably, the collar (42) is integrated into the protector body (20). The collar (42) is connected to the body of the protector by means of a part connecting the body of the protector with a reduced cross-section (45). The collar and its connecting portion with the protector body have an L-shaped cross section or alternatively a V-shaped cross section if the connecting section has a reduced length. The flange has a face (44) with an orientation chosen to minimize the contact surface with the inner annular surface (28), on the one hand, to favor a greater contact pressure than that which would be obtained if the contact surface between the face (44) and the inner annular surface (28) was larger and, on the other hand, to minimize any deterioration of the coating or surface finish, which would be applied to the inner annular surface (28).

[0096] The outer seal (43) projects radially outwardly in the form of a flange (or projection or lamella) intended to contact the outer annular surface (27) of the female connection (13) to provide continuous local sealing around its entire circumference when the protector is placed in a bolted condition in its final position. Preferably, the collar (43) is integrated into the protector body (20). The flange (43) has a radially measured height and an axially measured thickness, measured at half height in the axial direction, such that the height-thickness ratio is greater than 1, preferably greater than 3. Thus, the flange may have a first slope in the free state and a second slope in the axial flex when the protector is placed in its bolted condition in its final position. Preferably, the flange (43) has a rounded face (45), which on the one hand minimizes the contact surface between the flange (43) and the outer ring surface (27) to facilitate contact pressure and minimize the risk of deterioration of the surface finish or coating applied to the outer ring surface (27) on the other hand, to facilitate rolling without slipping or friction, the collar on the outer ring surface, so as to avoid damaging the surface finish or coating. This geometry significantly reduces the risk of contact loss when the surface quality deteriorates and the dimensional tolerances of the connection are wide.

[0097] The external threading (37) comprises a first threaded portion (38) comprising two threads with pitch P1 and a second threaded portion (39) comprising at least one thread with pitch P2 other than P1.

[0098] The value of P2 is P2 = P1 + (A x P1), wherein the factor A is strictly greater than 0 and smaller than the value such that the pitch offset is less than the difference between the distance WTC separating the two threads of the connection and the width TW1 of the thread step P1, such that: 0 <A <(WTC-TW1) / P1 [0099] Alternatively, the coefficient A is between 0.1 and 0.8. The value of coefficient A depends on the size of the connection and the threading characteristics of the connection and threading of the protector.

[0100] The first threaded portion (38) may comprise 1 to 5 threads with a pitch of P1.

[0101] Screwing the protector (40) to the female connection (13) breaks according to the following steps:

• At the first engagement stage, the threads with P1 pitch are supported by their coupling sides on the sides of the coupling threads of the connection threading.

• At the contact stage, the flange (42) contacts the inner annular surface (28) and then deforms by bending.

• At the deformation stage, the support sides (74) of the threads with pitch P1 come into contact with the support sides (77) of the threading the connection. Indeed, the deformation of the collar (42) pushes the body of the protector below the joint, the movement of the protector is then limited by the threading of the protector meshing on the threading of the connection. The inner annular surface (28) is still deformed by bending when the protector is screwed on.

• At the stage of the second coupling, at least one thread with pitch P2 meshes with the threading of the connection and comes into contact with the internal threading (26) of the female connection. Due to the thread offset with P2 pitch, the contact pressure of the support sides (74) of the threads of the first threaded part (38) decreases.

• At the stage of reducing the contact pressure, optional and preferential in this embodiment of the protector, the contact pressure of the bearing sides of the first threaded portion (38) decreases to zero and no longer contacts the bearing sides (77) of the threads of the female connection. The coupling sides of the threads of the first threaded part (38) may not touch the coupling sides of the threading of the connection with a properly selected A value.

• At the locking stage, the outer flange contacts the outer annular surface (27) of the connection. Threads with P2 pitch of the second threaded part (39) are deformed.

[0102] During the locking step, the support sides of the first threaded portion (38) may come into contact with the support sides of the threading connection, but with less contact pressure than exerted by means of the lateral thread surfaces of the second threaded portion (39) on the threaded surfaces of the connection.

[0103] Preferably, the threads with pitch P2 of the first threaded portion (38) are in contact with the incomplete threading thread surfaces (26) of the joint (2) when the protector (40) is screwed onto the joint (2).

[0104] Thus, in this embodiment for which the protector is equipped with elastic sealing means, the protector is subjected to a first force in the first axial direction on the body of the protector facing down the connection, due to the force exerted by the ring surfaces on the elastic sealing means of the protector, and the protector is subjected to a force in the second axial direction opposite to the first force of the first axial direction, exerted by at least one support side of the threading connection on the at least one support side of the thread with pitch P2, which allows energy storage to prevent screwing / unscrewing movements caused by vibration during transport. Threads with P1 pitch are maintained in the position with pressure reduced by the pressure of the thread with pitch P2, and even the pressure force with connection threads which is equal to zero. The risk of deterioration of coatings applied to threading by threads with pitch P1 is significantly reduced.

[0105] Thus, the protector according to the invention is more resistant to accidental unscrewing, both partial and complete, when it vibrates during the transport of pipes on which the protectors are mounted, or when moving these pipes. The protection of the pipe connection is more reliable.

[0106] Figure 6 illustrates the step of reducing contact pressure when screwing the protector (40) on the female connection (13) on the threading of the protector (40). The first and second threaded portions (38) and (39) are not shown with threads where the tops of the threads are in contact with the bottom of the connection threads, but contact may occur depending on the temperature to which the protector and connection are exposed.

[0107] Each thread of the first and second threaded portions (38) or (39) includes a coupling side (73) and a supporting side (74). Each threading thread (26) of the female connection also has a coupling side (76) and a supporting side (77). At this stage of reducing the contact pressure during screwing, the bearing side of the thread with pitch P2 contacts the bearing side of the threading connection, and the pitch P2 is such that the bearing sides of the thread with pitch P1 no longer contact the bearing sides of the connection. Indeed, the pitch offset between the thread with pitch P1 and the thread with pitch P2 is smaller than the difference between the distance WTC separating the two threads of the protector and the width TW1 of threads with pitch P1, that is, A is strictly greater than 0 and smaller than Amax, so that Vmax = (WTC - TW1) / Pl [0108] The coupling sides of the threads also no longer contact the coupling sides of the threads of the connection. The coatings or surface finish of the threading connection are preserved during storage, handling and transportation on the sides of the threads.

[0109] Preferably, the at least one thread with pitch P2 is set to mate with incomplete connection threads, while the protector is screwed to the connection. These threads are less loaded by the connection in oil wells, the consequence in the form of degradation of their coating or surface finish is less than in the case of perfect threads.

[0110] The protector may be equipped with more than one thread with P2 pitch, which allows increasing the total force exerted on all threads with P2 pitch or reducing contact pressure on all threads with P2 pitch. The protector may contain 1.5 threads with P2 pitch. The protector may also contain, for example, 2 to 4 threads with a pitch of P2.

[0111] In one embodiment of the invention, the threading (21) or (37) comprises 5 threads with P1 pitch and 2 threads with P2 pitch. The advantage of this solution is a better distribution of stress applied to the threading coatings of the joint (4) or (26).

[0112] According to one embodiment of the protector according to the invention adapted for a male or female connection comprising two threads of the type shown in figure 2, i.e. a male or female connection comprising two threads (4a, 4b) instead of a single threading (25; 26); the protector may include threading (21) or two threads intended for cooperation with threads (4a) and (4b) respectively. A first threaded portion comprising at least one thread with pitch P1 and a second threaded portion comprising at least one thread with pitch P2 may be included in each upper and lower threading of the protector or in at least one of the two upper and lower threads of the protector.

[0113] For example, each threading between upper and lower threads may contain 2 to 3 threads with P1 pitch and one thread with P2 pitch. Either single threading between top threading or bottom threading may comprise one threading with P1 pitch and one threading with P2 pitch. An advantage of this aspect of the invention is to limit the threading portion (4) that could damage the coating through the threads of the protector.

In a variant, the upper threading and the lower threading comprise a first threaded part with one or more threads with a pitch P1, one of the two upper or lower threads having a second threading part with at least one thread with a pitch P2, such that P2 = P1 + AxP1 and a second thread among the upper and lower threads containing a third threaded part with at least one thread with pitch P3, so that P3 = P1 - B x P1. A and B are two factors strictly greater than 0. A and B are less than 0.8. Preferentially, A and B are smaller than the Amax value.

[0115] Preferably, in this embodiment, at the end of the screwing of the protector at the end of the element, the bearing side (s) of the thread (s) (74) with a pitch P2 are in contact with the threading support sides, while the coupling sides of the thread with a pitch P3 are in contact with the coupling sides of the threading. When threads with pitch P2 and threads with pitch P3 engage respectively with threads (4b) and (4a), the stresses exerted simultaneously by these threads increase the torque necessary to put on the protector to screw it to the connection or unscrew it, securing it in this way in position. The choice of position of threads with P2 pitch and threads with P3 pitch depends on whether it is desirable to increase the contact pressure on the threads with the P1 pitch or, on the contrary, to reduce the contact pressure of said threads with the P1 pitch, as explained for the embodiments related to figures 3 and 4.

[0116] The thread pitch offset with the P2 pitch can be obtained on the coupling side or on the supporting side. It can be obtained by changing the average pitch of the thread, or it can be obtained by changing its width TW or by combining these two methods of obtaining. Only changing the pitch of the thread while maintaining a constant cross-section of all threads is a cheaper solution due to simpler machining than that involving a change in the cross-section of the thread.

[0117] The dimensions of the protector and the relative position (s) of the thread (s) with pitch P2, sealing flanges are chosen according to the geometry and dimensions of the connection. In practice, positions and dimensions can be calculated based on the dimensions of the connection and relative to the reference surface of the connection depending on the geometry of said connection, in accordance with calculation practices known to those skilled in the art.

Vallourec Oil and Gas France Agent:

PL-PAT-2012-2196

EP 3 209 850 B1