Premium connection torque shoulder

Abstract

To provide a torque shoulder for fixing or capturing a pin in a box that reduces or eliminates movement of the pin relative to the box.SOLUTION: A threaded tubular connection includes: a pin 20 having external threads 22, a pin seal surface 24, and a pin torque shoulder 26 at a free end; and a box 120 for receiving the pin, the box having internal threads for interacting with the pin threads, a box seal surface 124 for contacting the pin seal surface and a box torque shoulder 126 for contacting the pin torque shoulder. The pin torque shoulder has a curved pin shoulder surface. The box torque shoulder has a curved box shoulder surface.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] This application is a continuation of U.S. Patent Application No. 15 / 449,350, filed March 3, 2017, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to threaded pipes and connectors for such pipes that may be used in the oil and natural gas industry. For example, a pipe may have an end with a pin that fits into a box at one end of a connector, and the pipe and connector are connected by threading. The connector may have a second box for a second pipe with a second pin so that the pipe and second pipe are connected through the connector. [Background technology]

[0003] WO 84 / 04352 is said to describe a tubular joint or connector of box and pin members having double tapered threads. Two metal-to-metal seals of complementary mating sealing surfaces are provided. Reverse angle torque shoulders on the ends of the pin members and internal terminations of the box members and hooked threads further characterize the joint and the box and pin members.

[0004] U.S. Patent No. 4,623,173 is said to describe a threaded joint coupling for oil pipes. The main seal portion includes a seal portion that is axially convex at the end of the male thread and a seal portion that is tapered inside the female thread, and the end of the male thread abuts against the end of a stopper formed inside the female thread.

[0005] U.S. Patent No. 4,624,488 is said to describe a tubular connection having an internal frustoconical sealing surface cooperating with a counterbore in a box member on the free end of a pin member. The internal sealing surface of the pin member is inclined inwardly at substantially 14 degrees from the axis of the tubular connection adjacent the end of the pin member. The inclination angle of the box internal sealing surface is substantially the same as the inclination angle of the pin inner surface. A pilot surface or bull nose located from the distal proximal end of the pin member toward the distal end, inclined to a lesser extent than the inclination angle of the pin member inner surface substantially parallel to the axis of the connection, defines a flat thickness increase in the pin end.

[0006] U.S. Patent No. 7,334,821 is said to describe a threaded tubular connection having an externally threaded element and an internally threaded element. The externally threaded element has an external thread and a free end with a non-threaded lip between the thread and the free end. The internally threaded element has an internally tapered internal thread and a non-threaded portion between the internal thread and the lug. The internally threaded element includes an annular axial abutment surface. When the external thread is fully configured within the internal thread, the free end abuts the annular axial abutment surface and the other bearing surface radially interferes and is under metal-to-metal contact pressure to form a metal-to-metal sealing surface.

[0007] In the '821 patent, a separate axial abutment surface is formed on the forward face of the free end of the male threaded element, and a single lip seal surface is disposed on the lip at an axial distance from the end of the threads. The lip includes an appendage between the distal axial abutment surface and the single lip seal surface, the appendage having an outer circumferential surface facing the female threaded member that is different from the lip seal surface.

[0008] U.S. Patent Publication No. 2014 / 0145433 is said to describe a tubular connection including a pin and a box member. The pin member has a first threaded structure and a helical torque shoulder axially spaced along the pin member from the first threaded structure. The box member has a second threaded structure and a second helical torque shoulder axially spaced along the box member from the second threaded structure. Upon rotation, the helical torque shoulders engage each other.

[0009] During the construction of a premium connection between a threaded tube with a pin, such as a pipe, and a threaded tube with a box, such as a connector, the following steps occur: (1) the pin on the pipe is threaded into the connector until the crests of the threads contact; (2) the pin is then threaded into the box until the pin seal face first contacts the box seal face, defining a position called "hand tight"; (3) the pin is threaded further into the box until the end of the pin, the so-called torque shoulder, just contacts the corresponding torque shoulder on the box, defining a position called "shoulder tight", this additional rotation from the hand tight position to the shoulder tight position creates an interference fit between the pin and the box seal; (4) the pin is then further tightened to generate additional torque to define the final construction position called "power tight".

[0010] The distance between the pin torque shoulder and the box torque shoulder when the connection is in the hand tight position is called the "standoff." When the shoulder tight position is reached, the standoff is removed. A large standoff can be problematic because the pin and box seal faces will come into contact during removal of the standoff. The large amount of rotation required to reduce a large standoff will cause galling of the seal faces, thereby compromising the seal. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] International Publication No. 84 / 04352 [Patent Document 2] U.S. Pat. No. 4,623,173 [Patent Document 3] U.S. Pat. No. 4,624,488 [Patent Document 4] U.S. Pat. No. 7,334,821 [Patent Document 5] US Patent Publication No. 2014 / 0145433 Summary of the Invention [Problem to be solved by the invention]

[0012] It is an object of the present invention to reduce or eliminate movement of the pin relative to the box by providing a torque shoulder that secures or captures the pin within the box, e.g., the torque shoulder prevents the pin from moving radially, bending, or deforming.

[0013] An alternative or additional object is to provide a connection that is easy to manufacture. [Means for solving the problem]

[0014] The present invention provides a threaded tubular connection, comprising: The present invention includes a pin having male threads, a pin seal surface, and a pin torque shoulder at a free end, and a box for receiving the pin, the box having female threads for interacting with the pin threads, a box seal surface for contacting the pin seal surface, and a box torque shoulder for contacting the pin torque shoulder. The pin and box define a longitudinal axis. The pin torque shoulder has a first pin shoulder surface and a second pin shoulder surface, the first pin shoulder surface intersecting an axis perpendicular to the longitudinal axis at a first angle, and the second pin shoulder surface intersecting the perpendicular axis at a second angle. The box torque shoulder has a first box shoulder surface and a second box shoulder surface, the first box shoulder surface intersecting an axis perpendicular to the longitudinal axis at a third angle, and the second box shoulder surface intersecting the perpendicular axis at a fourth angle.

[0015] The present invention further provides another threaded tubular connection, the threaded tubular connection including a pin having an internal thread, a pin seal face, and a pin torque shoulder at a free end, and a box for receiving the pin, the box having external threads for interacting with the external threads, a box seal face for contacting the pin seal face, and a box torque shoulder for contacting the pin torque shoulder. The pin and box define a longitudinal axis. The pin torque shoulder has at least one pin shoulder surface having a pin radius, the at least one pin shoulder surface being curved relative to the longitudinal axis. The box torque shoulder has at least one box shoulder surface having a box radius, the at least one box shoulder surface being curved relative to the longitudinal axis.

[0016] The present invention also provides a method of forming a threaded tubular connection, the method comprising: providing a pin having external threads, a pin seal surface, and a pin torque shoulder at a free end, the pin torque shoulder including a first pin shoulder surface extending in a first direction and a second pin shoulder surface extending in a second direction; providing a box having internal threads, a box sealing surface, and a box torque shoulder at a free end, the box torque shoulder including a first box shoulder surface extending in a third direction and a second box shoulder surface extending in a fourth direction; a step of inserting a pin into the box to engage the male and female threads; rotating the pin relative to the box until the pin seal surface contacts the box seal surface; and further rotating the pin relative to the box until the first box shoulder surface contacts the first pin shoulder surface and the second box shoulder surface contacts the second pin shoulder surface.

[0017] Preferred embodiments of the present invention will now be described with reference to the following drawings. [Brief description of the drawings]

[0018] [Figure 1A] FIG. 2 shows a detailed view of a torque shoulder as known in the art. [Figure 1B] FIG. 2 shows a detailed view of a torque shoulder as known in the art. [Figure 1C] FIG. 2 shows a detailed view of a torque shoulder as known in the art. [Figure 1D] FIG. 2 shows a detailed view of a torque shoulder as known in the art. [Figure 2A] 1 shows a cross-sectional view of a premium connection for oil pipes according to the invention in a second stage of construction, in the hand-tight position. [Figure 2B] 1 shows a cross-sectional view of a premium connection for oil pipes according to the invention in a second stage of construction, in the hand-tight position. [Figure 3A] The third stage of construction, showing the connection in the shoulder-tight position. [Figure 3B] The third stage of construction, showing the connection in the shoulder-tight position. [Figure 4] 1 shows a cross-sectional view of a premium connection for an oil pipe according to the invention, where the pin of the oil pipe is inserted into the box of the connector. [Figure 5A] FIG. 5 shows a detailed view of the torque shoulder shown in FIGS. 2A to 4 according to the present invention. [Figure 5B] FIG. 5 shows a detailed view of the torque shoulder shown in FIGS. 2A to 4 according to the present invention. [Figure 6] FIG. 13 shows a detailed view of an additional embodiment of a torque shoulder according to the present invention. [Figure 7] FIG. 13 shows a detailed view of an additional embodiment of a torque shoulder according to the present invention. [Figure 8] FIG. 13 shows a detailed view of an additional embodiment of a torque shoulder according to the present invention. [Figure 9] 5C shows a force diagram of the forces applied to the pin according to the embodiment shown in FIGS. 5A and 5B. [Figure 10A] 1 shows a further preferred embodiment of a torque shoulder according to the present invention. [Figure 10B] 1 shows a further preferred embodiment of a torque shoulder according to the present invention. [Figure 11A] 1 shows another preferred embodiment of a torque shoulder according to the present invention. [Figure 11B] 1 shows another preferred embodiment of a torque shoulder according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] FIG. 1A shows a conventional torque shoulder and metal-to-metal seal combination known in the art. Box 1520 includes box seal face 1524 and box torque shoulder 1526. Pin 1420 includes pin seal face 1424, nose 1428, and pin torque shoulder 1426. As shown in FIG. 1, pin seal face 1424 is located at the end of pin 1420. Nose 1428 of pin 1420 is pressed between pin seal face 1424 and pin torque shoulder 1426 when the connection is made. The connection between pin 1420 and box 1520 defines a longitudinal axis of the pipe and connector (not shown). Axis X is perpendicular to the longitudinal axis and passes through the ends of torque shoulders 1426, 1526 at pin nose 1428. The pin torque shoulder 1426 and the box torque shoulder 1526 each include a single shoulder surface angled with respect to the vertical axis X. The included angle A formed between the torque shoulder 1426, 1526 and the vertical axis X may be, for example, about -15°, i.e., 15° clockwise from the axis X. This inclination angle is known in the art. In this example, the pin nose 1428 is wedged tightly between the box seal surface 1524 and the box torque shoulder surface 1526. See, for example, U.S. Pat. No. 7,334,821.

[0020] FIG. 1D shows a premium connection known in the prior art. FIG. 1B shows a close-up of the connection of FIG. 1D at the point where the torque shoulders 1426, 1526 are just beginning to contact. A gap Sc exists between the outer surface of the pin 1420 and the counterbore surface of the box 1520 and is necessary to facilitate assembly. Although angle A is beneficial in locking the pin 1420 and the box 1520 together after assembly, FIG. 1C shows that angle A will cause the pin 1420 to crash into the box 1520 if the connection is screwed further. This unwanted contact can prevent proper positioning of the connection during assembly and can cause damage to the sealing surfaces 1424, 1524 or the torque shoulders 1426, 1526.

[0021] According to the present invention, a premium connection is provided that includes advantages over the prior art, for example, pin movement may be controlled and unwanted contact and damage to the above-mentioned sealing surfaces may be reduced. The premium connection includes a pin and box torque shoulder with multiple surfaces, for example, each torque shoulder may have upper and lower torque shoulder surfaces with respect to the orientation shown in Figures 2A to 11B. Another feature according to the present invention also includes a sealing surface spaced apart from the shoulder surface, as shown in Figures 2A, 3A and 10A. Additional features include a space that exists between the end of the pin and the end of the box or connector even after the pin is positioned in a final position. See Figures 5A and 6 to 8 and 10A.

[0022] In a preferred embodiment, both the upper and lower torque shoulders of the pin and box may contact each other simultaneously. In this way, the connector provides a neutral capture for the pin. In another preferred embodiment, the upper torque shoulder surfaces of the pin and box may contact each other before the lower torque shoulder surfaces of the pin and box contact each other. In this embodiment, the pin may bend downwards. See FIG. 6. In a further preferred embodiment, the lower torque shoulder surfaces of the pin and box may contact each other before the upper torque shoulder surfaces of the pin and box contact each other. In this embodiment, the pin may bend upwards. See FIGS. 2B and 3B. As a result, the movement of the pin can be controlled as desired.

[0023] FIG. 4 shows a cross-sectional view of the oil pipe 10 and connector 100 in the first stage, pierced position. FIG. 2A and FIG. 2B show the connection of the oil pipe 10 and connector 100 in the second stage after rotation has occurred. The oil pipe 10 has a pin 20 with a threaded portion 22, a pin seal face 24, and a torque shoulder 26 at its free end. The pin torque shoulder 26 includes a first surface 26a and a second surface 26b. The connector 100 has two boxes 120, 120'. Each box 120, 120' has a threaded portion 122, a box seal face 124, and a torque shoulder 126 on a radially inner protrusion 150. The box torque shoulder 126 includes a first surface 126a and a second surface 126b. In this embodiment, the first box shoulder surface 126a is complementary to the first pin shoulder surface 26a, and the second box shoulder surface 126b is complementary to the second pin shoulder surface 26b.

[0024] The connector 100 has two free ends 102 and 102' as shown in Figure 4. As mentioned above, in the inserted position, the oil pipe 10 is inserted or placed into the connector 100 until the threads 22 of the pin 10 contact the threads 122 of the box 120, 120'. No rotation has yet occurred between the pin 10 and the box 120, 120'. Once the pin 10 and the box 120, 120' have rotated, a connection is made.

[0025] This second stage of configuration is known as the hand tight position where the threads 22, 122 or seal faces 24, 24 just begin to contact each other. The threads 22 of the pin 20 mesh with the threads 122 of the box 120. The pin seal face 24 and the box seal face 124 just begin to contact. In the hand tight position, a gap or standoff "Sa" exists between the first surface 26a, 126a of the pin torque shoulder 26 and the box torque shoulder 126, and a gap or standoff "Sb" exists between the second surface 26b of the pin torque shoulder 26 and the box torque shoulder 126b. In this embodiment, the standoff Sa is, for example, about 0.06 inches, and the standoff Sb is, for example, about 0.03 inches. The standoffs Sa and Sb may be different as a result of the designed seal interference and seal angle, and need not be the same.

[0026] A nose 27 extends from the end of the pin 20. The nose 27 is located between the inner surface 21 and the outer surface 23 of the pin 20 along the length of the torque shoulder 26 in the direction of axis P, which is an axis perpendicular to the longitudinal axis. The nose 27 is an apex that connects the first surface 26a and the second surface 26b of the torque shoulder 26. In this embodiment, the first surface 26a extends in one direction from the outer surface 23 to the nose 27 and extends in a second direction around the circumference of the pipe 10. The second surface 26b extends in one direction from the inner surface 21 to the nose 27 and extends in a second direction around the inner circumference of the pipe 10. The location of the nose 27 is different from the location of the nose 1428 shown in FIG. 1A. In FIG. 1A, the nose is located at one end of the torque shoulder 1426 on the outer surface of the pin 1420 and at or near the pin seal surface 1424. As shown in Figures 2A to 11, the nose 27 is not located at one end of the pin torque shoulder 26. Instead, the nose 27 is at the middle or center of the pin torque shoulder 26 with respect to the length of the shoulder 26 in a profile view. The shape of the nose 27 may be various, for example, square, socket, flat end, bullnose, bulb, cone, rounded, fishtail, etc. The recess 127 is located along the length of the torque shoulder 126 in a direction perpendicular to the longitudinal axis and is an apex connecting the first surface 126a and the second surface 126b. In this embodiment, the shapes of the nose 27 and the recess 127 are complementary so that when the pin 10 is threaded into the connector 100, the nose 27 and the recess 127 mate and the recess 127 contacts the nose 27 and the pin shoulder 26 contacts the box shoulder 126. (Figure 5).

[0027] The difference in width between standoff Sa and standoff Sb occurs because nose 27 is not initially aligned with recess 127 with respect to the longitudinal axis. As shown in FIGS. 2B and 3B, nose 27 is positioned below recess 127. This offset between nose 27 and recess 127 causes pin 10 to bend upward when nose 27 is received in recess 127. The bending of pin 10 forces nose 27 into recess 127, making the connection even tighter. In another embodiment, nose 27 may be positioned above recess 127, causing pin to bend downward, making the connection even tighter. See, for example, FIG. 6.

[0028] 3A and 3B show the third stage of the configuration, the first shoulder tight position, which occurs after further rotation of the pin 20 relative to the box 120. The sealing surfaces 24, 124 are forced together by threading the pin 20 into the box 120 until the torque shoulders 26, 126 contact each other. In this preferred embodiment, for example, the complementary second surfaces 26b, 126b just contact each other. As a result, the standoff Sb between the second surfaces 26b, 126 is eliminated. However, the standoff Sa between the complementary first surfaces 26a, 126a still exists. Since no additional rotation has yet occurred after the contact point between the shoulders 26, 126, no additional torque force is applied to the shoulders 26, 126 in this position. A radial distance S1 exists between the end of the pin 20 and the surface BS of the box 120. The relative angle of the sealing surfaces 24, 124 presses the end of the pin 20 and the surface BS of the box 120 apart by the seal interference S1 designed into the connection to provide sufficient contact pressure to form a leak-proof seal.

[0029] The fourth stage of configuration, the second shoulder tight position, occurs after further rotation of the pin 20 relative to the box 120. By threading the pin 20 into the box 120 until the torque shoulder first surfaces 26a, 126a contact one another, the sealing faces 24, 124 are forced further together. The radial distance S1 is reduced by the radial offset between the apexes 27, 127. Pressing the ends of the pin radially outward brings the sealing faces 24, 124 even closer together, providing an even better seal. The V-shape between the first and second shoulder faces prevents the gap S1 from going to zero and creating undesirable contact between the box and the pin.

[0030] The fifth and final stage of making the connection is the power tight position. During the power tight stage, additional torque is applied to the torque shoulder 26, 126, but little additional rotation occurs (e.g., about 0.01 turns). Because little additional rotation occurs, the power tight position of the connection looks like the shoulder tight position shown in Figures 3A and 3B.

[0031] The amount of torque increase is a function of friction, pin stiffness, box stiffness around the seal area, thread interference (if applicable), lubricant, and seal interference. Once the seal faces 24, 124 contact each other, the torque begins to increase rapidly. The torque increase is caused by the seal faces 24, 124 being forced together. The torque continues to increase at a nearly constant rate until the shoulders 26, 126 contact at a shoulder-tight position. Once the shoulders 26, 126 contact each other, the torque increases very rapidly. Once the shoulders 26, 126 contact each other, additional torque is applied until a predetermined power-tight position is reached and the desired amount of torque is achieved. Very little additional rotation of the connection is required (e.g., about 0.01 turns) to reach the desired final configuration torque.

[0032] 5A and 5B show cross-sectional views of an embodiment of a torque shoulder according to the present invention. As shown in 5A and 5B, in the embodiment of 2A to 4, the pin 20 is designed as a male part and the box 120 is designed as a female part, so that the box 120 can receive the pin 20. In this embodiment, both the pin torque shoulder 26 and the box torque shoulder 126 have a V-shaped cross section. The pin seal surface 24 and the box seal surface 124 are spaced apart from the respective torque shoulders 26, 126 with respect to a longitudinal axis (not shown) defined by the connection of the pipe and the connector. The torque shoulders may have a cross section of another shape or design.

[0033] The V-shaped extension of the pin torque shoulder 26 engages the V-shaped receiving portion of the box torque shoulder 126 to reduce or prevent the pin 20 from moving in multiple directions, such as radially inward or outward. For example, the first surface 26a, 126a keeps the nose 27 of the pin 20 downward, thereby preventing the pin 20 from being driven upward into a corner of the box 120. The second surface 26b, 126b also prevents externally applied pressure from forcing the pin 20 inward, thereby reducing the bias of the sealing surfaces 24, 124.

[0034] An interior angle Va is formed between the first surface 26a, 126a and the axis P. The interior angle Va may be 15°, which is 15° in a counterclockwise direction with respect to the axis P. An interior angle Vb is formed between the second surface 26b, 126b and the axis P. The interior angle Vb may be -15°, which is 15° in a clockwise direction with respect to the axis P. The angles Va, Vb may vary, for example, 3 to 60° and -3 to -60°, respectively. Furthermore, the interior angle Va may be different from or equal to the absolute value of the interior angle Vb. For example, as shown in FIG. 5B, the angle Va is 15°, which is not equal to the absolute value of the angle Vb, which is -45°, and 15° ≠ |-45°|, so Va ≠ |Vb|. In another example, angle Va may be 20° and angle Vb may be −10°, in which case 20° ≠ |−10°|, and therefore Va ≠ |Vb|.

[0035] As shown in FIG. 5B, the nose 27 and recess 127 are located at or near the center torque shoulder relative to the length of the shoulder 26a, 26b, 126a, 126b in the direction of the axis P. The first pin face 26a has the same or approximately the same length as the second pin face 26b, and the first box face 126a has the same or approximately the same length as the second box face 126. In the embodiment of FIG. 5B, the nose 27 and recess 127 serve as the apex of the interior angles Va, Vb, which is a non-limiting example of a preferred embodiment. The shape of the torque shoulder 26, 126, including the nose 27, recess 127, and angles Va, Vb, is variable. Different shapes and apex locations may be used. Different shapes or angles of the surfaces 26a, 26b, 126a, 126b or Va, Vb may be used. For example, the location of nose 27 need not be in the center of torque shoulder 26 , but instead may be located closer to inner surface 21 than to outer surface 23 .

[0036] As shown in another preferred embodiment in FIG. 6, the first surface 26a, 126a is longer than the second surface 26b, 126b, and the first angle Va is greater than the absolute value of the second angle Vb. FIG. 7 shows that the first surface 26a, 126a is shorter than the second surface 26b, 126b, and the first angle Va is smaller than the second angle Vb. The shapes of the first surface 26a, 126a, the second surface 26b, 126b, and the apex (nose, recess) 27, 127 are designed to achieve the desired result. As mentioned above, the apex 27, 127 may be initially misaligned, for example, to press down on the end of the pin to straighten or minimize bending of the pin. Alternatively, it may be necessary to press up on the end of the pin 20, for example, to increase the contact pressure against the seal 24, 124.

[0037] FIG. 8 shows another preferred embodiment of the torque shoulder 26, 126, which has a bullet, bullnose or curved shaped cross section, as opposed to the V-shaped cross section shown in FIGS. 5-7. The first surface 26a has a first radius Ra, the second surface 26b has a second radius Rb, the first surface 126a has a third radius Rc, and the second surface 126b has a fourth radius Rd. The first and third radii Ra, Rc may be different or equal to the second and fourth radii, Rb, Rd, respectively. The nose 27 is located between the first surface 26a and the second surface 26b. The recess 127 is located between the first surface 126a and the second surface 126b. As described above with respect to the V-shaped cross-section embodiment, the first surface 26a, 126a, second surface 26b, 126b and radii Ra, Rb, Rc, Rd and apex may be adjusted to push the pin 20 up or down to capture the pin 20 in a desired position relative to the box 120. In another embodiment, the pin may have a single surface with a single radius and the box may have a single surface with a single radius. In this embodiment, the pin radius and the box radius may or may not be equal, and the centerlines of the radii may or may not be the same distance from the axis. If the two radii are radially offset relative to each other, the ends of the pin will be forced upwards or downwards depending on how the two radii are offset.

[0038] The V-shaped and bullnose cross-sectional design of the torque shoulder 26, 126 is advantageous over the prior art because the male and female shapes capture or restrain the pin in a radial position within the box, thereby reducing or preventing pin migration. By adjusting the design of the shoulder 26, 126, pin bending, curvature or deflection may be compensated for or minimized. Additionally, the contact pressure of the seal face 24, 124 may be increased. Other benefits may result therefrom as well.

[0039] Preferably, the first and second angles Va, Vb or the first and second radii Ra, Rb are designed to be small enough so that the relatively large component of the force F acting on the pin 20 is an axial component A rather than a radial component R. See FIG.

[0040] 10A and 10B show a pin and box torque shoulder connection in which the V-shaped shoulder design is inverted compared to the embodiment shown in FIGS. 2A to 9. In this embodiment, the pin 220 is the female member and the box 320 is the male member. The box 320 includes a box seal surface 324, a first shoulder surface 326a, and a second shoulder surface 326b. A nose 327 is formed between the first shoulder surface 326a and the second shoulder surface 326b. The pin 220 includes a pin seal surface 224, a first shoulder surface 226a, and a second shoulder surface 226b. A recess 227 is formed between the first shoulder surface 226b and the second shoulder surface 226b. In this embodiment, the apex between box faces 326a and 326b forms nose 327, and the apex between pin faces 226a and 226b forms recess 227. Because nose 327 and recess are complementary surfaces, nose 327 is received in recess 227 by rotating pin 220 within box 320 in the same manner as described above with respect to Figures 2a-5B. This inverted shoulder design may also be applied to the bull nose embodiment shown in Figure 8.

[0041] 11A and 11B show a torque shoulder connection according to a further preferred embodiment of the present invention, in which the pin 520 and the box 420 have different shoulder surface shapes and the vertices 527 and 427 are not complementary to each other. FIG. 11A shows a pin 520 having a rounded or bullnose shoulder surface 526 having a first shoulder surface 526a and a second shoulder surface 526b. The vertex 527 is located between the first shoulder surface 526a and the second shoulder surface 526b. The box 420 includes a V-shaped box shoulder surface 426 having a first shoulder surface 426a and a second shoulder surface 426b. The vertex 427 is located between the first shoulder surface 426a and the second shoulder surface 426b. The pin 520 and the box 420 contact each other in the same manner as described above with respect to Figures 2A-5B. Rotation of the pin 520 into the box 420 results in contact of the first shoulder surface 526a with the first shoulder surface 426a and contact of the second shoulder surface 526b with the second shoulder surface 426b. In the embodiment shown in Figures 11A and 11B, due to the different surface shapes of the shoulder 526 and the shoulder 426, the apex 427 and the apex 527 cannot contact each other. After construction, there is a gap or space 530 between the apexes 426, 526. Also, due to variations in the shape and design of the shoulder surfaces 526, 426, the shoulder surfaces 526, 426 do not contact each other along a portion of the surfaces 526, 426.

[0042] 11B shows a pin 520 having a V-shaped pin shoulder surface 526 and a box 420 having a rounded or bullnose box shoulder surface 426. The pin shoulder surface 526 has a first shoulder 526a and a second shoulder surface 526b. The apex 527 is located between the first shoulder surface 526a and the second shoulder surface 526b. The box shoulder surface 426 has a first shoulder surface 426a and a second shoulder surface 426b. The apex 427 is located between the first shoulder surface 426a and the second shoulder surface 426b. The pin 520 and the box 420 contact each other in the same manner as described above with respect to FIGS. 2A-5B and 11A. Rotation of pin 520 into box 420 results in contact of first shoulder surface 526a with first shoulder surface 426a and contact of second shoulder surface 526b with second shoulder surface 426b. A space 530 exists between vertices 427 and 527.

[0043] 11A and 11B, the pin 520 and box 420 may be designed such that the vertices 527 and 427 are aligned with one another such that the pin shoulder surfaces 526a, 526b contact the box shoulder surfaces 426a, 426b as the pin 520 is inserted into the box 420 during construction. Alternatively, the shoulder surfaces 526, 426 and the vertices 527, 427 may be designed such that the first shoulder surfaces 526a, 426a contact first, and then the second shoulder surfaces 526b, 426b contact as the pin 520 is threaded further into the box 520. In another variation, the shoulder surfaces 526, 426 and vertices 527, 427 may be designed such that the second shoulder surfaces 526b, 426b contact first, and then the first shoulder surfaces 526a, 426a contact as the pin 520 is screwed further into the box 520.

[0044] The shoulder surfaces 426, 526 may be designed in a variety of shapes, including, for example, but not limited to, bullnose, bullet shaped, squared, rounded or fishtail.

[0045] In the foregoing specification, the invention has been described with reference to certain exemplary embodiments and examples thereof. It will, however, be apparent that various modifications and changes can be made therein without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are therefore to be regarded in an illustrative manner and not in a restrictive sense.

Claims

1. 1. A threaded tubular connection, comprising: a pin having external threads, a pin seal face, and a pin torque shoulder at a free end; a box for receiving the pin, the box having female threads for interacting with the male threads, a box seal face for contacting the pin seal face, and a box torque shoulder for contacting the pin torque shoulder, the pin seal face being axially spaced from the pin torque shoulder; Including, The pin and the box define a longitudinal axis; the pin torque shoulder has a pin torque shoulder shape including a first outwardly facing pin shoulder surface and a second inwardly facing pin shoulder surface, the first pin shoulder surface and the second pin shoulder surface meeting at the pin apex; the box torque shoulder has a box torque shoulder geometry including a first inwardly facing box shoulder surface and a second outwardly facing box shoulder surface, the first box shoulder surface and the second box shoulder surface meeting at a box apex; the pin torque shoulder shape is not complimentary to the box torque shoulder shape, resulting in a gap between the pin apex and the box apex after formation of the threaded connection; a first pin shoulder surface intersects a normal axis perpendicular to the longitudinal axis at a first angle, a second pin shoulder surface intersects the normal axis at a second angle, the pin shape is V-shaped, and the box shape is rounded or curved; Threaded tubular connections.

2. A threaded tubular connection, comprising: a pin having external threads, a pin seal face, and a pin torque shoulder at a free end; a box for receiving the pin, the box having female threads for interacting with the male threads, a box seal face for contacting the pin seal face, and a box torque shoulder for contacting the pin torque shoulder, the pin seal face being axially spaced from the pin torque shoulder; Including, The pin and the box define a longitudinal axis; the pin torque shoulder has a pin torque shoulder shape including a first outwardly facing pin shoulder surface and a second inwardly facing pin shoulder surface, the first pin shoulder surface and the second pin shoulder surface meeting at the pin apex; the box torque shoulder has a box torque shoulder geometry including a first inwardly facing box shoulder surface and a second outwardly facing box shoulder surface, the first box shoulder surface and the second box shoulder surface meeting at a box apex; the pin torque shoulder shape is not complimentary to the box torque shoulder shape, resulting in a gap between the pin apex and the box apex after formation of the threaded connection; a first box shoulder surface intersects a vertical axis perpendicular to the longitudinal axis at a first angle, a second box shoulder surface intersects the vertical axis at a second angle, the pin shape is rounded or curved, and the box shape is V-shaped; Threaded tubular connections.

3. 2. The threaded tubular connection of claim 1, wherein a portion of the first pin shoulder surface does not contact a portion of the first box shoulder after configuration of the threaded connection.

4. 4. The threaded tubular connection of claim 3, wherein a portion of the second pin shoulder surface does not contact a portion of the second box shoulder after configuration of the threaded connection.

5. A threaded tubular connection as described in claim 1 or 3, wherein the first and second angles have absolute values ​​of 3 to 60° relative to the vertical axis.

6. 6. The threaded tubular connection of claim 5, wherein an absolute value of the first angle is different from an absolute value of the second angle.

7. A threaded tubular connection as described in claim 1 or 3, wherein the first angle is a positive angle relative to the vertical axis and the second angle is a negative angle relative to the vertical axis.

8. 4. A threaded tubular connection according to claim 1 or 3, wherein the absolute value of the first angle is greater than the absolute value of the second angle.

9. 2. The threaded tubular connection of claim 1, wherein the pin apex and the box apex are offset from one another relative to the longitudinal axis.

10. 10. The threaded tubular connection of claim 9, wherein the amount of offset is selected to improve contact pressure between the pin seal surface and the box seal surface.

11. 4. A threaded tubular connection as claimed in claim 1 or 3, wherein the first and second angles are selected such that a relatively large component of the force acting on the pin is an axial component force.

12. 2. The threaded tubular connection of claim 1, wherein the box seal surface is configured to contact and form a seal with the pin seal surface, forming a gap between the pin and the box between the seal and the pin torque shoulder.

13. 1. A threaded tubular connection, comprising: a pin having external threads, a pin seal face, and a pin torque shoulder at a free end; a box for receiving the pin, the box having female threads for interacting with the male threads, a box seal face for contacting the pin seal face, and a box torque shoulder for contacting the pin torque shoulder, the pin seal face being axially spaced from the pin torque shoulder; Including, The pin and the box define a longitudinal axis; the pin torque shoulder has a pin torque shoulder shape including a first outwardly facing pin shoulder surface and a second inwardly facing pin shoulder surface, the first pin shoulder surface and the second pin shoulder surface meeting at the pin apex; the box torque shoulder has a box torque shoulder geometry including a first inwardly facing box shoulder surface and a second outwardly facing box shoulder surface, the first box shoulder surface and the second box shoulder surface meeting at a box apex; A threaded tubular connection, wherein the pin torque shoulder shape is curved or rounded and the box torque shoulder shape comprises a line or a square, or the pin torque shoulder shape comprises a line or a square and the box torque shoulder shape is curved or rounded.

14. 14. The threaded tubular connection of claim 13, wherein the pin seal surface and the box seal surface form a seal, and a gap is formed between the pin and the box between the seal and the pin torque shoulder.

15. 1. A method of forming a threaded tubular connection, comprising the steps of: providing a pin having external threads, a pin seal surface, and a pin torque shoulder at a free end, the pin torque shoulder including a pin torque shoulder configuration having a first outwardly facing pin shoulder surface and a second inwardly facing pin shoulder surface that meet at a pin apex; providing a box having internal threads, a box seal surface, and a box torque shoulder at a free end, the box torque shoulder including a box torque shoulder configuration having a first inwardly facing box shoulder surface and a second outwardly facing box shoulder surface that meet at a box apex, the pin seal surface being axially spaced from the pin torque shoulder; inserting the pin into the box so that the male and female threads interlock; rotating the pin relative to the box until the pin seal surface contacts the box seal surface; further rotating the pin relative to the box until the box shoulder surface contacts the pin shoulder surface; Including, The method wherein the pin torque shoulder shape is curved or rounded and the box torque shoulder shape is linear or angular, or the pin torque shoulder shape is linear or angular and the box torque shoulder shape is curved or rounded.

16. 16. The method of forming a threaded tubular connection as recited in claim 15, wherein the pin seal surface and the box seal surface form a seal and a gap is formed between the pin and the box between the seal and the pin torque shoulder.

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