JPS59159485A - Pipe joint for oil well pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for extracting natural gas and crude oil from underground in Hasuda fields.
! This relates to pipe fittings for oil country tubular goods that are dug vertically deep into the ground in order to achieve this.

The depth of the wells that produce all the crude oil is approximately 1,100 (1,100,000,000
In recent years, its depth has increased further, reaching 10,000 m. In this way, a huge number of oil country tubular goods are installed vertically in one house, and they are all connected in series by pipe joints. Various severe forces act on pipe joints. First, connect μi in series and also the temperature of the tube y1℃
The second is the compressive force on the outer circumferential surface due to the soil snow, and the third is the pressing force on the inner circumference Htn due to the internal fluid. Needless to say, these forces become even more severe as the well deepens. The two most important requirements for pipe fittings subjected to such harsh conditions are to withstand strong tensile loads and to maintain reliable airtight sealing. Many pipe joints have been proposed to meet these demands.
For example, Special Publication No. 57...7630, Special Publication No. 41
-1742 Publication, Japanese Patent Publication No. 45-18096, Japanese Patent Publication No. 52-2736i, and furthermore, the United States ↑, y, r
r-<'Ii No. 2907589 HJa+'fT, US (±1 special dr No. 2980451-'Jl small buttocks and US special i'f-Box 2992019 specification "The pipe fitting described in 1st class is missing. The back of these conventional 'iT joints is the most basic one, as shown in Figure 1.

Shown in Figure 1? [The 7th hand is a coupling A with a cylindrical external appearance, and a coupling A consisting of a, cl, and t that are screwed together from both ends of this coupling. The inner diameter decreases as it goes further in the axial direction from S to 6 Tapers.
A buttress-type internal thread is carved in the , P, and ■ standards, and an annular shoulder B is formed on the innermost central wall, protruding in the It and U directions. On the other hand, tube c,
a' is tl, and 11 of coupling A is attached to its end.
1. A male thread is provided to be screwed into the female thread.

If you enlarge the left side of the part indicated by the dirt 1 song in Figure 1, you will see that it is ``+'' in Figure 2.
The male thread of the rc is not cut, and there is a lip without a thread in the range corresponding to 1.5 to 3 threads beyond the vll-min (to the right) -fk'tJ ○
The outer circumferential surface of this lip part continues with the IIJ stage male thread! , /16 External seal surface T finished smoothly with Taber
) 1 is hollowed out, and a tip sealing surface D2 having an overhang-like shape (having an angle of about 100° with respect to the axis of the tube C) is formed at its tip by a smooth finish. On the other hand, everyone near shoulder B in coupling A. A non-threaded part with a taper is provided, and an inner circumferential seal surface B1 corresponding to the outer circumferential seal surface D1 according to the lip 1V1 and an abutment seal curved horse corresponding to the tip seal direction D2 are formed. . When the threaded state of the pipe C and the coupling A is strongly tightened, the outer circumferential seal i'In DI and the inner circumferential seal surface, and the tip seal ih+ Dz and the abutting seal surface B, respectively. When the two metal parts come into contact with each other, an airtight sealing state is obtained where the two metal parts come into contact with each other.

The pipe joint constructed as described above has a problem in that the sealing property may be damaged when the pipe joint is screwed together and when used underground. The problem when tightening the screws is that a reliable seal is achieved by the pressure between the seal curves that come into contact with each other, so it is easy to tighten the screws with excessive IW. In the final stage of sealing, the sealing surfaces rub against each other under strong pressure, resulting in galling (scorching) on the sealing surfaces, which impairs the sealing performance.
) is a thing. The problem when vertically installing underground is that if a strong tensile load is applied to the pipe 1, there will be a gap between the male screws of 1 and 1, loosening the screws 1 and 1, which will impair the sealing performance. It is said that it will be done. About this problem i+, :I
Third state? Further explanation will be given with reference to the following. Figure 3 shows the ridges Ha of the alternate threads engraved on the coupling AK and the ridges f engraved on the pipe C.
In addition, Jif (one set of screw threads Sc is shown in an enlarged view. A tensile load T (50~
When a load of 1000 tons) is applied, a force f acts on the female thread Sa Vc at point O on the slope E where the female thread Sa and the male thread Sc touch. In this force, there is a component force f1 in the axial direction and a component force perpendicular to the axis f1.
It can be divided into two parts of force. The component force f1 acts to stretch the inner surface J @ of the coupling, and the component force f2 acts to expand the diameter of the coupling A'. 4) The cuff'+- is acting], or are they the joint end A of the 21st Yuso 1?
, (/-)) 11-min.

On the other hand, a similar force acts on the 4th mountain (Sc), which is shown by the broken line 1, 1, 31', and the 31'JK dashed line. Due to the tensile load T in the direction, the component force f between the axes and the axial center causes the sail elongation and inclination to occur, and the component force f; <1.''U, a gap occurs between the screws of IIL711 near the joint end A1 of the coupling A, which causes loosening of the screw engagement and impairs the sealing performance. In view of the above-mentioned drawbacks of conventional pipe joints, tightening screws should be done so that the sealing surfaces do not sometimes rub against each other, and to minimize loosening of the screw connection when used vertically. The purpose is to ensure reliable airtight sealing of pipe joints.

Below, the oil country pipe joint (hereinafter referred to as "wood pipe joint") according to the present invention is shown in FIGS. 4 to 7. This is a schematic diagram of the entire shelf shown in the 415i Ume Main Pipe Joint Complete Book 1. In the same figure, 1 (, j is the coupling, and 6 and 6' are the pipes screwed together from both ends of the coupling l. There are flat 11"D111" screws 3, 3' cut into the inner surface of the navy blue end parts 2, 2' on both sides of the coupling 10 (. 'Kohouchi 1111 power'
11+ Line is parallel to and parallel to finish the horizontal line.
111ζ4 is formed by cutting out ¥.

The C on both sides of the ridge +yB 4 are #1.7'i: voids 5.5' formed when cutting out the ridge 4. On the other hand, each tube 6, 6')
Parallel male thread 8.8 corresponding to 4+1 female thread 3.3'
' is engraved, and C [screw 8.
A parallel, smooth and slanted lip portion 9.9' is formed at the other end of the exposed portion, and the tip surface of the lip portion 9,9' is
Seals u11i o and 1 o' are formed. Then, screw the tubes 6, 6' onto the ends 1lls 2, 2' on both sides of the cup link 1, and the lip in<
When the tip seal curves of 9°9', 0, and 10' come into contact with each other, a similar sealing state is obtained, which is a metal curve versus a metal curve. In addition, male and female screws 3, 8 and 31, sl
Isn't it the buttress type that fits the A, P, and ■ standards for both JL and A? We are hiring.

The structure of the wood pipe joint - 1 - What is different from the conventional pipe joint is that the screws are screwed to the left side from the center of the tS joint (male and female screws 3 and 8 screw into each other at the vinyl stone side). There is a difference in pitch between the female and male screws 3' and 8', and the female J
The male and female screws 3' and 8' screwed into each other on the right side with the screws 3 and 8 on the 4F must have a uniform left-hand thread with a stone-grained design, and all screws should be aligned with respect to the axis. The point is that they are parallel. Regarding these points,
This will be explained with reference to FIG. 5. FIG. 5 is a schematic enlarged view of the central portion of the cross section h■ of FIG. 4. In the figure, p is the pitch of the male and female screws 3.8 screwed together on the left side of the raised portion 4, and l'' is the pitch of the male and female screws 3f and sr screwed together on the right side. So p
<p' or p>p'. Pitch p and p' jump) λ: (・Well, it goes without saying that it specifically varies depending on the size of the base wall pitch of the screw to be carved in the tube to be connected and its 'rr'. none)
However, j... is 0.1-10 for commonly used oil country pipe joints.
Select r and JM within the range of +nffI. σljU male screws 3 and 8 that are screwed together on the left side, and screws 1 on the right side.
With screws 3' and 13', if'? The reason why we unified the right-handed and left-handed threads so that both joint ends 2 and 2' are threaded in the same direction is that the tube ends 7° and 7' are screwed into both joint ends 2 and 2', and both lip parts 9. Place the cup links 12 in close proximity to each other and tighten the cup links 12 in the direction in which the large pitch screws are tightened.
In the case of rotational tightening ratio, the reason is that the lip part that moves at a small pitch and the lip part that moves at a large pitch track and contact each other, regardless of the pitch difference (due to the slow speed relationship). The larger the difference, the faster the tightening will be, but recurved tightening will make it difficult to control the timing.Next, the reason why all the screws are parallel threads is that the female and male screws with left side force and the right side force The female Jt's neck is the common right side U
Or, in the case of a left-handed screw, one screw is tightened, but the other screw is moved in the direction of loosening 11J7. If the threads in this twisted relationship are made into Taber threads, a sudden separation will occur between the internal threads that move in the loosening direction and the fRIW and sealing performance at the same time
This is to prevent the occurrence of the 111 condition. Parallel threads can also be tightened with a smaller torque than Taper threads, and the pipe connection work is easier. J<9,
! , )' is the length. Lip part purity l, g' is 165 to 2.0 times the pitch l) or p'. It also serves as a stopper to prevent the joint ends 7, 7' from entering the joint ends 7, 7'.
1, 9 and 9' serve as a backup for the joints that extend outward and deform due to fluid pressure within the pipe. -A role like Ini? In order to perform, the lip length is 1゛4W inside the bulge 14ζ4! or p′
Approximately 1°5 times 7? , c, One thing about the screw that is different from the conventional one (1) In the cross-sectional shape of the screw, there was a trapezoidal one (C')? , slanted) 17 rows 4; horn shape 11, especially when made into a slanted parallelogram, stripes, Jll screw crest tube 6.6' wooden body side also slanted 1 fr + a dllf I water) same crest cutoff 1.Turn the slope on the central side in an obano-tsuku shape (fj+) against the root surface of the thread of
'I have made this point obsolete. Regarding this point, refer to No. 61 to 1 for clarification. Figure 6 shows the 11 areas circled in Figure 5.
It is an enlarged view of 1-minute. In the same figure, 3a is 111
This is the thread of the E screw 3, and 3b is the turn of the thread 3a on the center side of the cup link 1 (or tjfs+). The primary 8a is the thread of the male thread 8, and 8b is the thread of the thread 8a on the side of the tube 6 body (oblique direction).The slopes 3b and 8b are the threads of the male and female threads
L! : Closely attached in a threaded relationship with 8. this? Looking at the slope 3b, it is inclined at an angle θ in an overhanging manner with respect to the root surface 3C of the thread.

This inclination angle θ is the same for the oblique direction 8b since both the female thread 3 and the male thread 8 are parallel threads.

When a tensile load T in the direction of the white arrow is applied to the tube 6, an rf force acts on the internal thread 3a at a point O on the diagonal itl 3b and 8b that are in close contact, and this force f is These forces can be decomposed into an axial component force f1 and an axial component force f2. These forces are almost the same except that the direction of each force is reversed for the male thread 8a. is shown with a broken line. In this case, component force f, f2 joint y of coupling 1, tM capital 2 or expanding E f = restrains the rice grains and elephants that are about to be expanded, and component force ji is pipe yj of pipe 6? H part 7 is X
This will completely prevent the phenomenon of separation between the male screw and the inner screw shown in the third quotient, and will strengthen the tightness between the coupling and lrk. The inclination angle θ in 111J was set to 3 to 200.

A more important feature of the main pipe joint is that the seal has a drilled hole and the lips of both pipes are brought into contact with each other. J
There are various cross-sectional shapes.The one shown in Figure 5 is one with a triangular protrusion on one side of the seal, and a 10"V-shaped groove on the other side. 7 (a) to (d).
) has both seal tins with male and female Theban faces, and the most sophisticated is 1. I can stay in LJ. The degree of taper is normal. ~It's my duty.

In (8) (b), a convex arc surface is formed at both ends, and one 11. The seal ring 12 is fitted with a seal ring 12 made of a material such as -1.The inner surface of the seal ring 12 is designed to create an internal pressure 1 [1], and a seal sound effect 1 (more than sipping) is created in response to fluctuations in the internal pressure. In (c) of the same figure, one seal has a convex curved crest 1 and the other seal surface has a V-shaped groove. Lano 11, Sone, Dashi ↑ A reliable sealing effect can be obtained. (d) in the same figure shows that one seal has a curved convex arc 1h + binding and the other seal has a groove with a concave arc. In the groove, a sulin (13) is bored in the axial direction.The sulin (13) can elastically deform the tip of the lip part, so a certain curved ball suitable for sealing is provided on both sealing surfaces. The cross-sectional shape of the sealing surface Q-↓ is not limited to that shown in the drawings. Any material that can be brought into direct contact with the pre-curved lip of the tube may be used.
Next, a case will be explained in which pipes are connected using the above-mentioned main pipe joint. First, screw the tube with the small pitch thread into the coupling. This will be explained with respect to the pipe joint shown in FIGS. 4 and 5. Screw together the left side joint end 2Vc of the coupling l with the pipe end 7 of the pipe 6 until the tip thread of the male thread 8 touches the protrusion 4 or almost comes into contact with it. .

In this case, the seal 1fn10 of the lip portion 9 is
It lies slightly to the right, beyond the center of ζ4. Next, screw the tube end 7' of the tube 6' into the right joint end 2', and tighten the seal surface 10"i of the lip 9' at a position close to the already screwed seal IJIIIO of the tube 6. 1
Screw it in by r1 inch. Then /ii' in such a state
6 and 6'? Hold it with a chuck, etc. In this case, the chuck is equipped with a feather key or the like and is movable in the axial direction of the tube 6.6'. Therefore, the tubes 6 and 6' held by the chuck can move freely during the anal rotation, but are restrained so that they cannot rotate in the circumferential direction. Rotate the coupling 1 in the direction in which the threaded tube end 7' will spiral forward (B) and tighten with Power Tight. When doing so, the left tube end 7 will tend to move slightly to the left. , the right-hand tube end 7' moves to the left earlier by the pitch difference, and the sealing surface 10' follows and abuts against the sealing surface 10. When the sealing surface 10' comes into contact with the sealing surface 10, the rotational torque of the Power Tight increases rapidly. It is best to stop tightening when the rotational torque of the Power Tight reaches the specified value. At this time, the seal [11] 10.10' is the raised part 4
It is located approximately in the center of the metal surface and maintains an airtight seal with the appropriate surface pressure necessary for sealing. The sealing surfaces 10.10' also do not rub against each other under surface pressure, so that galling does not occur. Although it is not mentioned in 1 above, when using a pipe connected with a main pipe joint as a drill pipe, it is necessary to rotate it in the direction in which the screw is tightened. Apply to the connection of
We tested the occurrence of goring and the presence or absence of leakage, so what are the results? 0 shown in Tables 1 and 2. This means that the capacity pipes are connected with the specified tightening torque, a full internal pressure equivalent to 1.1 times the specified internal pressure is applied to the pipe, and 1 of the specified tensile load is applied in the axial direction of the pipe.
．． A full tensile load equivalent to 4 times V was applied.

Table 1 Table 2 As is clear from Tables 1 and 2, even if the main joint is tightened and untightened 50 times, the seal If
lTVc galling will not occur (with a force of λ 0 that does not cause leakage even if an internal pressure equal to 1°1 times the specified internal pressure and a tensile load equivalent to 1.4 times the specified tensile load are applied). In addition to the above-mentioned effects, it also has excellent effects from the manufacturing perspective.In other words, the threads of conventional pipe joints were taper threads, and the sealing surface of the coupling was It was extremely difficult to process them with high precision because of the holes formed deep inside the pipe, but since the main pipe joint has parallel threads and the sealing surface is only formed on the end face of the pipe, it is difficult to process and process them. Repairs are easy.Also, conventional pipe joints had two seals per pipe joint, but the main pipe joint has one seal where the lips of both pipes touch. , the risk of leakage could be reduced compared to the conventional method.

[Brief explanation of the drawing]

Figures 1 to 3 explain a conventional pipe joint, with Figure 1 being an overall schematic diagram partially shown in cross section, and Figure 2 being an enlarged view of the left side of the sectional view of Figure 1. , Fig. 3 is a schematic diagram showing a state in which the female thread and the male thread are separated, and Figs. 4 to 7
The figures are for explaining the main pipe joint, and Fig. 4 is an overall schematic diagram with a partial cross section, and Fig. 5 is an enlarged schematic diagram of the central part of the section showing the fourth factor. Figure 6 is an enlarged view of the tfls portion circled in Figure 5, Figures 7 (a) to (d)
is a schematic diagram showing the Knoll curved shape of the lip tip.

Claims (1)

[Claims] ■, In a pipe joint that connects both pipes by screwing the pipe ends to the joint ends on both sides of the coupling, there is a female thread carved inward on the l'lil joint end and a 011 carving on the pipe end. The male and female threads are parallel buttress-type threads between the same left and right sides, and the male and female threads are in a threaded relationship on one side of the coupling, and the male and female threads are in a threaded relationship on the other side of the coupling. Is there a difference in pitch from the thread in the main pipe side of the O1J male thread that has a mutual VC-matching relationship? times (slope and 111 dij
The center side of the threaded coupling is also inclined at a face angle or an overhang to the root surface of each thread. A pipe joint for oil country tubular goods, characterized in that the IJ knobs are brought into contact and tightened to ensure a seal.