JPS58110793A - Joint of drill pipe tool - 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 relates to earth-poling drill pipes, and more particularly to tool joints for interconnecting sections of drill pipes.

Deep wells, such as oil and gas wells, are drilled with rotating drill bits that are rotated by strings of drill pipe. The drill pipe is completed by connecting together individual pieces, each approximately 30 feet (9-) long. Each member is connected to each other by a threaded joint called a tool joint.

The tool fitting must withstand the torques normally experienced during drilling and must also provide a sealing function to prevent drilling fluid being pumped down the drill pipe from leaking out of the fitting. Must be.

Because drilling fluids are aggressive, their leakage from tool joints causes wear and premature failure.

The tool joint is composed of a bottle member and a box member. The bin member has external threads and an external annular connecting shoulder.

The box member has internal threads and a surface or rim that abuts the connecting shoulder. Conventional drill pipes are provided with an inner shoulder within the box member that is to be contacted by the abutment surface of the bin.

When the tool joint members are connected, a torque is exerted between the box end face and the bottle connection shoulder to create a pressure of approximately 1/2 the yield strength.

If additional torque is applied during drilling, for example due to a bit or pipe becoming stuck, the bins and boxes can be subjected to forces that exceed their yield strength. Therefore, it is very important to use a tool joint that has the ability to withstand large torques, preferably greater than the drill pipe itself.

The present invention provides a tool joint with substantially increased yield strength without increasing the thickness of the bottle or box and without further hardening the steel. The box is provided with an inside shoulder on the underside of the screw. The bottle has a surface at its tip that abuts an inside shoulder within the box. The dimensions of the bottle and box are calculated so that the box end faces contact the outside shoulder of the bottle when hand-tightened. but,
There is a gap between the end of the bottle and the inside shoulder of the box. When the tool joint is fully connected to its normal connection torque, the box end faces will abut the outside shoulder of the bin with a normal pressure of approximately 1/2 the yield strength of the tool joint. The pin end face exerts little or no pressure on the inside shoulder of the box under normal connection torque.

During the drilling operation, if additional torque is applied, the tool joint tightens further, forcing the end of the bin against the inside shoulder of the box. The top portion of the bottle is selected to reach its yield strength at about the same time and no later than the point at which the sinking bulk of the box and the root portion of the bottle reach their yield strength. The inner connecting shoulder increases the amount of torque required to pull the tool joint apart.

Hereinafter, the present invention will be explained in detail with reference to the drawings. - the drawing shows an upper drill pipe member 11 installed in a lower drill pipe section 13; Drill pipe member 1
The ends of 1 and 13 are connected to each other to form a tool joint. The bin 15 is located at the lower end of the upper drill pipe member 11 and the lower end of the lower drill pipe section 13 (not shown).
is formed. Bin 15 has an outer annular connecting shoulder 17 . A relief 19 is provided around the inner circumference of the outer shoulder 17. Root portion 21 extends downwardly from outer shoulder 17. The outer shoulder 21 is cylindrical and unthreaded. A benchmark shoulder 23 is formed at a short distance downwardly from the connecting shoulder 17 for use in measuring the amount of metal removed from the connecting shoulder 17 during rework.

- A set of screws 25 is formed in the pin 15-hi on the underside of the root portion 21. Thread 25 is tapered and terminates in a cylindrical tip portion 27. The tip portion 27 terminates in a circular rim 29 lying in a plane superimposed on the axis of the upper drill pipe member 11 .

The upper end of the lower drill pipe section 13 is formed as a box 31, similar to the upper end of the upper drill pipe member 11 (not shown). Box 31 receives bin 15 and also includes a rim or surface 33 at the top end. Surface 33 is a circular, flat surface located in a plane perpendicular to the axis of lower drill pipe section 13. 33 abuts the outer shoulder 17 of the bottle 15. The bore of box 31 includes an upwardly directed shoulder 35 formed a short distance below surface 33 for use as a benchmark. Benchmark 35 serves to enable the user to know the amount of metal removed from surface 33 during re-addition.

A cylindrical sunken mass 37 is located just below the benchmark 35. The sunken major portion 37 extends approximately the same length as the root portion 21, but has an inner diameter that is greater than the inside diameter of the root portion 21. As a result, an annular shape exists between the root portion 21 and the sunken major portion 37. A cavity is formed.−
A set of internal threads 39 are located on the underside of the recessed major portion 37. The screw 39 has a tapered C and is formed to mesh with the screw 25.

The box 31 has a cylindrical root portion 41 located below the screw 39. The root portion 41 terminates in an L-oriented annular inner shoulder 43 . The inner chest 43 is positioned in the S17 plane within the mold with respect to the axis of the lower drill vibe portion 13, and is configured to be abutted by the bottle end surface 29. The relief groove 45 is formed at the intersection of the inner shoulder portion 43 and the root portion 41. The axial passage 47 of the box 31 below the inner shoulder 43 is connected to the axial passage 49 of the bin 15.
has a diameter equal to the diameter of A recessed annular area 51 is formed on the outer side wall of the sunken mass 37.

The recessed area 51 has a diameter slightly smaller than the outer diameter of the part containing the screw 39.

The box 31 and the bottle 15 are arranged such that the distance from the outer shoulder 17 to the bottle end surface 29 is from the box end surface 33 to the inner shoulder 43.
The dimensions are selected so that it is slightly shorter than the distance from The box 31 and the bin 15 are also arranged such that a gap exists between the bin end face 29 and the inner shoulder 43 when the two members 11 and 13 are connected by hand and without the use of a wrench or tool. The dimensions have been selected. When hand-tight, there is no pressure between the bottle end face 33 and the outer shoulder 17, but they are in contact with each other.

During operation, the drill vibe members 11 and 13 have a yield strength of approximately 2/1 of the yield strength of the bottle root portion 21 and the box submerged portion 37.
are connected with a torque that produces a pressure equal to .

Yield strength is the pressure (compressive or tensile) that causes permanent deformation of the bottle root portion 21 or box major portion 37.

As torque is applied, the large portion 37 sinks and contracts;
The bottle root portion 21 is elongated so that the bottle end (2) 29 advances downwards. With the necessary torque applied to the connection,
The bin end surface 29 is either at a very small distance from or in contact with the inner shoulder 43.

However, the pressure at the inner shoulder 43 is lowered by the pressure at the outer shoulder 47 (
) is smaller than the pressure.

The drill perve member is then lowered into the hole and rotated for drilling. During l-rilling, if the movement of the drill bit or structure at the lower end of the drill string is heavy, the joint is subjected to additional torque. Due to this additional torque, the sinking major portion 37 further shrinks, and the bottle root portion 21
is further stretched, so that the bottle end face 29 is pressed against the inner shoulder 43 and comes into tight contact. Ideally, the bottle base 21
The iJ method selection is performed so that the yield strength of the tip portion 27 is reached at approximately the same time as the cumulative yield strength of the box sinking bulk portion 37, or at a time no later than that. . The inner shoulder 4 is formed by the bottle end face 29.
The additional pressure applied at 3 increases the amount of torque required to yield the tool joint.

The root portion 21, the sunken major portion 37, and the tip portion 27 serve as spring means for pressing the box end face 33 tightly against the outer shoulder 17 with a pressure that exceeds the pressure exerted by the bottle end face 29 on the inner shoulder 43 during a. Play a role. The length of these members is such that, if subjected to additional torque during drilling, there is sufficient spring action to allow deformation of these parts ◆Δ, so that the bin end face 29 abuts the inner shoulder 43. It has been selected to To explain how these dimensions are determined, A, P, 1. (As+eri
can Petroleum l n5titut
e) Standard 32/1 inch (8,89c+n)1. F,
An example of changing a tool joint will be explained. First, holes 47 and 4
9 is a standard diameter hole for a factory fitting of this size, this dimension being 6.82 CIIl. drill vibe 2
The outside diameter of 1 is selected to be 9.36 CI, which is the minimum outside diameter of a standard tool joint in its last engaged pin thread. The minimum thickness of the root portion 21 is selected to ensure that the bottle 15 does not have a lower profile than the root portions of conventionally known bottles.

The cross-sectional area of the root portion 21 is 31.5619.

To ensure that the sunken mass 37 is not damaged substantially earlier than the bottle root portion 21, the sunken mass 37
The cross-sectional area of is selected to be substantially the same as that of the root portion 21. To accomplish this, in the preferred embodiment, the IIJ diameter of the sinkhole is determined by the standard sinkhole diameter of the tool coupling box. The outer diameter of the recessed area 51 is then calculated such that the cross-sectional area of the recessed bulk 37 is substantially the same as the cross-sectional area of the bottle root portion 21. The recessed area 51 serves to prevent the outer diameter of the recessed portion 37 from being worn 1F. (Otherwise, the cross-sectional area would be reduced below the design requirement.) If reduced below the design requirement, the sunken mass 37 would fail at an earlier point than the root section 21. Probably.

In the preferred embodiment, the outer diameter of the recessed area 51 is 12.2
It is 2cm. In a preferred embodiment, the inner diameter is 10.
35cm, resulting in a cross-sectional area of 33.1
It becomes 101'. The difference between the cross-sectional area of the bottle root portion 21 and the cross-sectional area of the sinking portion 37 is 1.55 [Q, approximately 5%.
This is the difference.

Next, the length of the sinking bulk 37 is selected. This length must be long enough to produce the necessary deformation when torqued. In the preferred embodiment, the length of the sunken majority 37 was chosen to be 2 inches (5.08 CI). The length of the root portion 21 was selected to be slightly longer, 5°56c+++, for threaded engagement.

The magnitude of the displacement in yield strength is then determined by dividing the yield strength of the steel used in this tool joint by Young's modulus. This value is 8,274/1,971
, 970=0.004c+Il/1cm. That is, when this type of steel material is subjected to a stress of 8.274 bar, it deforms (compresses or stretches) by 0°004 cm per cm of the length of the member.

During connection, the sinking major portion 37 contracts and the root portion 21 expands. 0, OO4c at 5°56 cm at a torque that produces a pressure of 1/2 of the yield strength or 4.147 bar.
Multiply by l/1 cm and divide by 2, 0°011125
cm. The sinking portion 37 is 2 inches long (5
, 08cm+n) by 0.004cm/ICll1 and divided by 2 to calculate the cross-sectional area of the root portion 21 vs. most of the sinking portion 37
It shrinks by an amount equal to the ratio of the cross-sectional areas. As a result, the total deformation at 1/2 of the yield strength is 0.009
It will be 67cm. Therefore, the total relative motion of the bottle end face 29 at 1/2 of the yield strength is 0.011125 cm+ and 0.00967c++ or 0.02079co++
7) Japanese teal. II Deformation at 3/4 of yield strength is 0.
03119 cm, and the deformation at yield strength is 0.0
416'Ocw+.

The length of the tip section 27 is selected to cause the tip section to reach yield strength at the same time as, or slightly earlier than, the bottle root section 21 and the sunken mass 37. To avoid making the length of the tip part longer than necessary, a norm was chosen in which the bottle end face 29 initially contacts the inner shoulder 43 at 3/4 of the yield strength. At this point, the bottle root portion 21 and the sunken major portion 37 are 0.00 mm below the bottle end surface 29.
3119CIlI is running. To reach the yield strength, the bottle root portion 21 and the sunken portion 23 are 0.0103
80- additional transformations must be made. Due to this deformation, the tip portion 27 becomes 0. '01' Shrinks 038cm.

The length of the tip portion 27 is 0. '01'038c - Selected to reach yield strength when compressed. As mentioned above, deformation of this type of steel occurs at a ratio of yield strength to Young's modulus or O,'004 cm/1 cm.

The shrinkage required for the tip portion 29 to reach the yield strength at the same time as the bottle root portion 21 and the sinking bulk portion 37 is approximately 0.
．． 01016 cm, the length of the tip portion 27 is 2
．． Must be 54C11.

For the outer diameter of tip section 27, screws 25 and 39 were truncated as much as possible without reducing their strength. The selected length is approximately 6.0325 cm. The outer diameter of the tip portion 27 is slightly less than the smallest outer diameter at the truncated ends of these screws, which in the preferred embodiment is 8.097 cm;
was selected as.

The next dimension to be determined is the position of the inner shoulder 43. In the configuration 1 standard, at the full coupling torque that produces a pressure of 1/2 of the yield strength at the outer shoulder 17, the bottle end face 29 is attached to the inner shoulder 43.
The idea is to apply a small amount of pressure (if any at all) to the object. The bin end face 29 was previously determined to move downward 0.02080 cm at full connection torque and a pressure of 1/2 yield strength. Bottle end face 29 when tightened by hand
The 0.030 cm gap between the inner shoulder 43 and the inner shoulder 43 is approximately 0.01 cm due to the 0.02080 cm movement due to deformation of the bottle root portion 21 and the sinking portion 37 at full coupling torque.
It will be reduced to 01cn+. When an additional torque is applied that exerts a pressure on the outer shoulder I7 to 3/4 of the yield strength, the bottle root portion 21 and the sunken major portion 37 become 0.010.
This results in an additional deformation of 38 cm. This results in a yield strength of 3
At a pressure of /4, the bottle end face 29 will first contact the inner shoulder 43. The additional torque that creates a pressure of 3/4 to 1 times the yield strength, if unconstrained, would move the bin end face 29 downward an additional 0.01038 cm. However, since the bottle end face 29 is in contact with the inner shoulder 43 at 3/4 of the yield strength, the tip portion 27 is 0.0103
8c- It will shrink. This is the amount of deformation experienced by tip portion 27 at yield strength. Therefore, the tip part 2
7 reaches the yield strength at the same time as the bottle root portion 21 and the sunken major portion 37.

When tightening by hand, there is no tension between the bottle end surface 29 and the inner shoulder 43.
．． To obtain the desired gap of 0.30 cm, the box end face 3
3 to the inner shoulder 43 is selected to be 0.030 cm + greater distance than the distance from the bottle outer shoulder 17 to the bottle end surface 29, that is, 14.584 cm. Although this is the ideal dimension, the actual manufacturing tolerance difference for one of these methods is 14°554 cm and 14.584 cm, totaling 31 cm.
The dimensions are plus 0 and minus 0.0127 cm. As a result, when tightening by hand, the bottle end face 29 and the inner shoulder 4
3 is between the minimum value of 0.0177 cm and the ideal maximum value of 0.030 cm. If the tool joint has a minimum clearance rather than an ideal clearance, the tip section 2
7 yields before the bottle root portion 21 or the sinking major portion 37 yields. Also, at full coupling torque, the bin end face 29 exerts a compressive force on the inner shoulder 43.

The reason is that the minimum gap of 0.0177cm when hand-tightened is due to the total deformation of 0.02080cn from hand-tightening until a pressure of 17/2 of the yield strength is applied. This is because it reduces by 0.00254c+n. A deformation of 0 DEG 00254 ci occurs in the tip section 27 at a pressure of 3/4 of the yield strength, while the bottle root section 21 and the sunken mass 37 are at a pressure of 17'2 of the yield strength.

The tip portion 27 reaches its yield strength at a contraction of 0.0101 cm. When the torque on the bottle root portion 21 and the sink portion 37 increases from 1/2 to 3/4 of the yield strength, these members deform by 0.01038 ci. Therefore, the tip portion 27 reaches its yield strength before the root portion 21 and the sunken major portion 37 reach 3/4 of the yield strength. Although this may result in cranking of the tip portion 27, this is less detrimental than if cranking were to occur in the root portion 21 or in the sinking mass 37. Cranking the tip portion 27 may cause separation of the drill string. Up to and beyond the point where tip section 27 yields, it has no ability to withstand additional torque.

Through standard calculations, the torque to yield the bottle root portion 21 or sinking portion 37 of the above Ig joint at ideal dimensions is 12.7 ft.
・cab). In comparison, a conventional conventional tool joint with an outer diameter of 12.7 cm and an inner diameter of 6.826 c+e does not have the ability to withstand an additional torque of 762.73 N·Cl at yield strength. This increase in the torque required to yield the tool joint further reduces the chance of drill string separation during drilling. The increased strength of the IM joint is achieved without increasing the thickness of the metal or increasing the strength of the steel.

Although the invention has been described in terms of one embodiment thereof, it will be apparent to those skilled in the art that various modifications may be made within the scope of the invention.

It is a front view.

DESCRIPTION OF SYMBOLS 11... Upper drill pipe member, 13... Lower drill pipe part, 15... Bin, 17... Outer shoulder part,
19... Relief groove, 21... Root portion, 23... Benchmark shoulder, 25... Screw, 27... Tip portion, 29... Bin end surface, 31... Box, 33...・
・Box end face, 35...Benchmark, 37...
Most of the sunken part, 39... Inner part, 41... Root part,
43... Inner shoulder, 45... Relief groove, 47.49.
...Axial passage, 51...Concave range

Claims (1)

Claims: A drill pipe tool coupling having a bin having an external thread formed between an outer shoulder and a bin end face, and a box having an internal thread and a box end face for coupling with the bin, comprising: When the inner shoulder located inside the box and the inner shoulder of the drill pipe are connected, a pressure exceeding the pressure applied to the inner shoulder by the drill pipe is applied from the box end face to the outer shoulder of the bottle, and if additional torque is applied, spring means disposed between the box and the bin for pressing the pin end face tightly against the inner shoulder if received during drilling.