MXPA00001674A - Integral joint for the connection of two pipes - Google Patents

Abstract

Integral joint of two pipes which comprises a first box element, equipped with an internal two-step thread, situated on the end of a first pipe, a second pin element, equipped with an external two-step thread, situated on the end of a second pipe, two metal-to-metal seals located at both ends and with at least two shoulders arranged at one end and at the centre of the joint respectively.

Description

INTEGRAL JOINT FOR THE CONNECTION OF TWO TUBES DESCRIPTION OF THE INVENTION The present invention is based on an integral joint of two tubes. More the present invention is related to a. Integral pipe system for pipes that will be used as a pipe dj = OZO. The term "tubing", as used in the present description and claims, refers to a tubular structure, consisting of several portions of tubing assembled together by a mechanical seal, installed inside a well for the production of hydrocarbons. , coiao reinforcement and support of the walls of the well itself. As it is known, the oil industry has a tendency to reduce the diameters of production wells, in order to obtain a reduction in drilling costs. To achieve this result, however, the connectors joining the tube portions to obtain the tubing must have a geometry that is substantially identical to that of the iaismo tubes, ie they have substantially the same external and internal diameter. Integral connections or joints, such as tongue and groove joints and almost tongue and groove joints, have been proposed for the purpose, having an external diameter equal to that of the tubes to be assembled (tongue and groove joint) or a slightly larger diameter (2 - 3.5%) (almost tongue and groove joint!) The disadvantage of these joints, however, is the supply of connections with mechanical properties, such as resistance to traction, compression, torque and bending, , which are much smaller than those of the tubes themselves.In particular ^ The tensile strength of tongue and groove joints or almost tongue and groove joints would be 65 75%.,. With respect to the body of the tube, depending on the diameter and thickness of the tube. The resistances a_ La. compression, a The bending and torque, which are often a traction of those of the tuba, san. even more - reduced. These reductions in the mechanical characteristics limit the applications of these connections to wells with a limited depth, with low pressures differentation to 1, and cure, they do not require, rotation while inserting the tube into the perioxation orifices (as indicated). requires for example in the case of lining the coating).

The almost tongue-and-groove integral joints of the type mentioned above, containing suitable modifications to improve the mechanical characteristics have been proposed in the literature in order to overcome these drawbacks. For example, the published international patent application WO 93/18329 describes an integral joint, machined on each end of the tubes to be assembled, formed of two elements, pin and box. Each element contains at least two threaded sections, each separated by a suitable connecting flange for coupling one into the other when the tubes are assembled. The published European patent application 767,335 discloses an integral j.unta for tubes, machined on each end of the tubes that are assembled, and formed of two threaded elements, pin and box, which has a conical longitudinal section. Chamfered The two threads are interrupted, in an intermediate position, by an orthogonal rim. 1 axis of the tubes .. To improve the sealing effect of the joint, the initial parts of the threads of the pin element, and the end portions of The threads of the box element have been removed, by mechanical processing, so that, when joined, the two surfaces come into contact with a subsequent elastic deformation of the surfaces involved. The connections described above, although having improved mechanical performance with respect to the tongue and groove type joint, are still not sufficient to guarantee the convenience for deep wells. The Applicant has now found an integral board, dei. almost tongue-and-groove type, characterized by a significant improvement in the resistance to compression and torque. The improvement is obtained by means of a particular design of the ends of the elements of pin and caj.a of the joint, as described below, which allows the machining of at least two flanges Cexterno and intermediate), to increase the resistance compression at a value close to the tensile strength and also the resistance to torque, whose maximum value is equal to about 2.5 times the joint torque of the joint. In addition ^, the presence of two metal seals (internal and external), together with the flanges and the particular two-stage threaded profile, allows the connection to have excellent resistance to the combined load, making it possible to tolerate extreme pressure, tensile, compression, bending and torsion torque in the well, making the connection very appropriate for deviated or horizontal wells, high pressure and high temperature. The object of the present invention therefore relates to an integral joint for the connection of two tubes comprising: a) a first box element with a conical-chamfered longitudinal section, equipped with a two-stage internal thread machined in a end of a first tube; b) a second pin member, equipped with an external two-stage thread machined at one end of a second tube, having a conical-chamfered longitudinal section suitable for splicing into the box element c) a rim, orthogonal to the .e of the tube, located on the pin member, midway along the thread; d) a flange, orthogonal to the axis of the tube, located in the middle, along the thread of the box element and suitable to be coupled with the flange of the pin element when the connection is formed; e) two intercalations machined at the beginning and at the end of the box element respectively, suitable for interfering with corresponding widens machined at the beginning and at the end of the pin member; characterized in that: f) between the broadening and the beginning of the thread of the pin element there is an annular groove, the depth of which which allows the thread to be machined) is recovered with a corresponding flange, which has a thickness - substantially equal to the depth of the slot, at the end of the XOS C?; g) between the initial insertion of the box element and the beginning of the corresponding thread, there is another annular groove, similar to the first one, the depth of which (which allows the osc. to be machined) is recovered with a possible corresponding flange , or is absorbed in the intercalation at the end of the thread. According to the present invention, it is therefore possible to obtain an integral joint, with at least two flanges, which has a slight increase in the external diameter (.2-3%) in correspondence with the joint itself, whose geometry consequently remains identical to that of the tubes that are going to be connected. In fact, due to the presence of the two slots, which can have a length in the range from 1 to 2 cm and a depth of 2-4 mm, depending on the diameter and thickness of the tube, the threads start from the portion of the tube with the smallest thickness so that, at the end of the thread, the thickness of the slot itself is recovered by the flanges. In this way, at least one extra flange can be obtained at the end of the joint, without having to increase the thickness of the. p-ar-ci on.es terminals, of the tubes that are going to be connected. The integral joint of two tubes object of Xa present invention can be more easily understood referring to the drawings of the appended figures, which represent an illustrative but not limiting modality, and in which: Figures 1 and 2 represent a longitudinal middle section of .the elements of pin and box of the joint formed with three flanges, along the axis XX, in the position not coupled / coupled; Figures 5 and 6 represent a longitudinal middle section of the pin and box elements of the joint formed with two ridges along the axis of the XX, in the unencoupled / coupled position, * Flots 4 and 7 represent a section Complete the joint with the elements of pin1 and box. In particular, the drawings represent the longitudinal section of the joint with three details, 4A, 43, 4C and 7A, 7B, 7C of the flanges / metal seal. Figure 4 refers to the joint with the three-flange design (one external, one intermediate and one non-internal); Figure 7 refers to the joint with only two flanges (one external and one intermediate). Figure 3 represents a partial view, along the X-X axis, of the profile of the thread, from which it can be seen that the preferred design includes both a negative loading angle and a positive entry angle. With reference to the Figures, il) indicates IB. a hollow end part of a box tube (3) equipped with an internal thread (2), while (4) indicates the corresponding hollow end part of a pin tube (5) equipped with an external thread (6). The elements of raisin, or and box of the tube have a conical-chamfered longitudinal section in which the conical zone varies from 8 to 16%, depending on the diameter and thickness of the tube. In correspondence with half of the two threads (2) and _ (.6), there is a flange (.7), which is orthogonal to the axis of the pipes, as detailed in Figures B. The ends of the integral joint present they are shown in Figures 4A / 7A and 4C / 7C respectively. The pin element of the joint object of the present invention is formed at the end with the flares (8) and (9) which, interfering with the internal intercalations (10) and (11) machined at the end of the box element, they form two metala-metal seals, internal and external, which guarantee the complete seal of the seal under any operating condition ^. Between the initial widening (8) of the pin element and the beginning of the thread (6), there is a slot 12) whose thickness is recovered at the end of the JCQSCB. by the flange (13) orthogonal. to the widening (9). Between the initial intercalation (11) of the box element and the beginning of the thread (2)., There is a groove (.141 whose thickness is recovered at the end of the thread by the flange (15) substantially orthogonal to the intercalation ( 10) (see Figure 4C). In the alternative solution this flange is not present See Figure 7C) but is absorbed by the intercalation (10) ^ For purely illustrative purposes, the mechanical characteristics of the joint according to the present invention, as previously described in Figures 1, 2 and Figure 4, are given below, related to tubes of 195.58 mm in diameter and 15.11 mm in thickness, the height of the rims being about 2 mnu. for the internal and external flanges, and of about 1.5 mm for the intermediate flange. The S-uma of the areas of the three flanges is about 3.5 QD mm2 with a line, cross section of the body of the. tube of about 8,600 mm2 and a cross-sectional area of the joint of 6,900 mm2. This gives a tensile efficiency of the resulting joint equal to about 80% of the elastic limit of the pipe body (tensile efficiency% = 6.3007.8 ^ 600 x 10D = 80) ^ Considering the area of the three flanges, the efficiency Compression is 50% of the traction efficiency (compression efficiency% = 3,500 / 6,900 x 100 = 50%). Also taking into account the contribution of the thread (which can be estimated at around 30%) the compression efficiency can be said to be equal to the joint tensile efficiency (around 80%).

Claims (1)

RE i and INDICATIONS

1. An integral joint for the connection of two tubes, comprising: a) a first box element with a conical-chamfered longitudinal cylindrical body, equipped with a two-stage internal thread machined at one end of a first tube; b) a second pin member, equipped with an external two-stage thread machined at one end of a second tube, having a conical-chamfered longitudinal section suitable for splicing into the box element, - c) a ridge, orthogonal to the tube axis, located on the pin element, half way along the thread; d) a flange, orthogonal to the axis of the tube, located midway along the thread of the box element and suitable to engage with the flange of the pin member when the connection is formed; e) two intercalations machined at the beginning and at the end of the box element respectively, suitable to interfere with corresponding widens machined at the beginning and at the end of the pin member, "characterized in that: f) between the broadening and the start of The thread of the pin element has an annular groove, the depth of which (which allows the hole to be machined) is recovered with a corresponding flange, which has a thickness substantially equal to the depth of the groove, in the end of the thread, 'g) between the initial intercalation of the box element and the start of the corresponding thread, there is another ring groove, similar to the first, the depth of which (which allows the thread to be machined) is recovered with a possible corresponding flange, or is absorbed in the intercalation at the end of the thread.