US2562298A - Safety joint for use in well strings - Google Patents

Description

2 Sheets-Sheet l July 3l, 1951 T. A. cRElGHToN SAFETY JOINT FOR USE 1N WELL STRINGS Filed Aug. 9, 1946 July 31, 1951 1', A; cRElGHToN l SAFETY JOINT FOR USE IN WELL STRINGS 2 'Sheet's-Sheet Filed Aug. 9, 1946 W'mw N N mi.

Patented July 31, 1951 Thomas s.. ereignen, Long Beach, Calif.; vera Neva Creighton executrix of said Thomas A.

Creighton, deceased Application August 9, 1946, Serial No. 689,623

use in a well string andit is a general object of the invention to provide a joint construction and operator therefor whereby a well string such as a string of drill pipe or the like can' be parted at a selected point whenever desired,- or neces- Sary y v Releasable connections or safety joints are desirable in well string and particularly in drilling strings since there are times when it becomes necessary or desirable to separate Vparts or" a. string while it is in the well. For example, in the course of drilling with the rotary method the bit is operated by means of a string of drill pipe vknown ordinarily as the Adrilling string, and it sometimes occurs that the bit or a portion of the drill string becomes stuck so that it cannot be withdrawn from the well. If no means is provided for disconnecting or breaking'the string at one or more predetermined points along-.its length it becomes necessary to try to remove it by iishing operations or by cutting it out and by any such means kor method the operation is hazardous, slow and expensive. Safety joints have been "proposed and in some Claims. (Cl. Z55-48) cases used in well drilling strings.- However, they are generally unsatisfactory because they are not always dependable and in most instances in troduce either a weak point in the drilling string or present hazards which are impractical.

It is a general objectv "of this invention' to provide a joint construction and operator therefor whereby a well string such, for example, as a string of drill pipe, can be disconnected or parted at any predetermined point ina well without resorting to fishing operations, cutting operations, or other like hazardous or costly methods.

A further object of my present invention is to provide a construction which enables the use of a plurality of joints or couplings in a single string under control of a simple, dependable operating device or tool whereby any one of the joints in the string can at will be released without in-` terfering with other joints. l

Itis a further object of my present invention to provide a joint construction which involves few simple parts which are of sturdy, dependable construction and which are easily formed andina-- nip-ulated. The joint or coupling provided by the present invention. resembles an ordinary tool joint in that it involves, primarily, a box section and a pin section threaded together andV in addition to such parts it involves a locking memn ber or locking liner splined to both sections and shiitable longitudinally out of engagement with 2 one of the sections when it is desired to release lthe joint.

Itis another object of rnyinvention to provide a simple easily manipulated, dependable tool iol' operating the joint of the present invention, which tool can be run into the well on a wire line and whichA is effective in engaging the joint in a proper manner and is operable to effectively actuate the lock liner of the joint.

The various objects and features of my inven tionwill be fully understood from the following detailed description of a typical preferred forro and application of the invention, throughout which description reference is made to the ao companying drawings, in which:

Fig. 1 is a sectional view of a well showing a well string or string of drill pipe therein which well string is shown provided at spaced points with couplings embodying the present invention. Fig. 2 is a longitudinal detailed sectional view of a coupling embodying the present invention showing it in locked or operating position and showing the operating tool that I have provided in position ready to be operated to release the joint or coupling. Figs. 3, 4 and 5 are detailed transverse sectional views taken on lines 3 3, ei-4, and 5 5, respectively, on Fig. 2. Fig. 6 is a longitude nal detailed sectional View of a portion of the drilling string taken through a coupling provided by the present invention showing the string clear or unobstructed as it is during normal operating conditions. Fig. lv is a view similar to Fig. 6 except'that it shows the operator or operating tool of the present invention lowered` into the string to a position from which it is adapted to be moved upward preliminary to being engaged with the lock liner or" the joint, and Fig. 8 is a View similar to Fig. 7 showing the operator after it has been engaged with the lock liner of the joint and the lock Vliner has been operated or moved to a position where the joint is released ready to be disconnected.

The equipment that I have provided bymy invention involves two distinct parts or units one a joint structure proper and the other an operator or operating tool that cooperates with the joint to release the joint so that it can be disconnected. ln carrying out my invention I may providea single well string S` with any desired number of couplings C embodying the present invention and I may locate the couplings at any suitable or desired points lengthwise of the string. In Fig. l of the drawing I have shown a well provided with a typical casing lil and have shown a well string S within the casing and involving lengths or sections of pipe such as drill pipe II joined by the usual joints I2 and having couplings C of the present invention inserted in certain of the joints I2 at the desired points.

The coupling C that I have provided may be applied directly to the sections of pipe to be connected although in practice it is advantageous to insert it in a joint I2 as I have shown in the; drawings. I show the coupling construction inserted between the upper part I3 of a joint and the lower part I4 thereof, the upper part being in the nature of a pin section having a tapered downwardly projecting pin part I5 and the lower part I4 being in the nature of a box section having an upwardly facing threaded box portion It to receive the pin.

The joint C of the present invention involves, primarily, three parts, two main sections l1 and I8 joined by threads I9 and a lock liner 2B that extends between and locks the sections l1 and I8 against being unthreaded. Where the joint C is to be applied as I have shown in the drawings the upper section I'l is provided at its upper end with a box portion 2i adapted to receive the pin I5 while the lower section I8 is provided at its lower end with a pin 22 adapted to be threaded into the box I6. The pin I5 and box 2| are threaded together in the manner common to tool joints, for instance, by coarse tapered threads and the pin 'Z2 and box I6 are threaded together in like manner. In accordance with standard practice it is preferred to make the threaded connections just described righthanded or such that they make up or tighten as the string S is operated or rotated in a righthanded direction, which is the direction in which it is rotated during vnormal operation.

In accordance with my invention the threaded connection between the sections I1 and I8 of the coupling or safety joint is established by providing a tapered pin 25 on one section to engage a socket portion 2E in the other section. The pin and socket connection may be straight or, as I have shown throughout the drawings, it may be tapered. In the particular case illustrated I have shown a pin 25 projecting from the lower end of the section Il' and I have shown a socket part 26 on the upper end of the section I8. I prefer to provide a tapered t between the parts 25 and 26 and to provide coarse threads 2l and 28 on the parts 25 and Z6, respectively, which threads serve as the means joining or connecting the sections I'I and I8. In the preferred construction the threads 2l and 28 are pitched opposite to those of the parts hereinabove described, or in other words, they are made lefthanded so that the coupling C is disengaged upon rotation of the upper portion of the string in a righthanded direction.

The lock liner 2S which I provide is an elongate tubular part fitted within the sections I1 and I8 having splined or keyed engagement therewith. In accordance with my invention the bores 3l) and 3l of the sections Il and I8, respectively, are provided with longitudinal keyways or splines 32 and 33, respectively, and the exterior of the lock liner 20 is correspondingly keyed or splined to have parts that mesh with or t the splines 32 and 33. This splined connection or engagement is clearly illustrated in Figs. 4 and 5 of the drawings. In accordance with my preferred construction the bore 30 or opening in the upper section Il extends downwardly and continuously through the section I'I from the socket 2l to the lower end of the pin 25 while the bore 32 in section I8 extends downwardly in the section I8.

lower portion is within the section I8 and since it has splined engagement with both sections it serves when in this position as a key or lock positively preventing relative rotation between the sections l1 and I8.

I may t the lock liner 20 into either one or both of the sections I? or I8 so that it is tight and requires positive operation to move it from theposition just described. However, I prefer to provide releasable retaining means that holds it in this position. In practice I may provide one or more detents or springs to hold the liner in active position. As shown throughout the drawings it is desirable to provide a shear pin 42 which acts to releasably hold the lock liner 20 in active position. I have shown a shear pin carried by the section I8 to extend into an opening in the lock liner and, in practice, I form the shear pin of a material that has the desired shear strength.

In forming and relating the parts of the coupling or joint C with the usual parts found on a well string S Ysuch as the parts I3 and I4 I prefer to make the bore 43 of the lock liner 20 substantially equal in size to the bores or openings 44 through the parts I3 and I4. In such case there is left or established an enlarged part or a portion of enlarged diameter at X above the lock liner 2|] and a similar enlarged part Y below the lock liner 2U.

The operator that I have provided, that is the tool that I provide for operating the joint above described involves, generally, a body 45 which is an elongate part small enough in diameter to t freely through the bores 43 and 44, or, in other words, of a size that can be freely run through the string and the various joints or couplings included therein. The body 45 is preferably run into the string S on or by means of a line L, and I prefer to couple the body to the lower end of the line L through or by means of a jar J and a sinker bar 45, the jar being provided as a means by which a jarring action can be imparted to the body and the sinker bar being provided as a mass whereby an effective blow is gained through the jar. The operator that I have provided further includes one or more grabs or dogs 50 carried by the body and effective to cooperate with the lock liner 20 and it includes means 5I for expanding the dogs 5B to working position upon the tool being manipulated in a predetermined manner.

The body 45 in its preferred form is a simple elongate part round in cross section and provided with side recesses 56 in which the dogs 50 are carried. In the particular arrangement illustrated I show three dogs 50 it being understood that any desired number of dogs may be employed as circumstances may require.

Each dog 5U is retained in its recess 55 by or on a pivot pin 5'I and it is so formed and shaped as to normally hang by gravity in a retracted position such as is shown in Fig. 7 of the drawings. In the retracted position the dog 5@ will pass freely through the various openings or parts of the string S without interference. In its preand out as shown in Fig. 2 the finger extends v substantially straight down. In constructing the dog 5S I provide a working shoulder (iiiv at the outer end of the linger 59 which shoulder faces down when the linger is out and extends down as shown in Fig. 2. Further, I provide the finger with a smooth and preferably straight outer side or face @Iv which extends downwardly and inwardly from the point where the arm joins the nger when the dog is retracted as shown in Fig. 7, and I provide the dog with an inner sideV or faceSZ which is a straight cam face except near the outer end of the dog where it is beveled or pitched as at $3.

The means 5i for expanding or operating the dogs 5e preferably includes a stern 'I0 slidably supported by the body iii and depending therefrom, an operating head 'II on the upper end of the stem operating in a chamber 'I2 formed in the body from its lower end and a tail piece -friction control forthe stem IQ. The stern enters the lower end of the body or extends into the chamber 'F2 through a retainer Mi threaded into the lower end of the body while the head'fII is an enlargement on the stem and is held by the retainer so the stem does not drop out of theV body. The lhead Il has a rounded upper end which when the head is moved upward from a` down position, as shown in Fig. 7, engages the end portions S3 of the cam faces of the dogs and then rides up along the cam faces E2 causing bowed outwardly and are such as to normally'Y frictionally engage in thewell string or in the bore M of a part on the well string to establish resistance or to create friction. A spring pressed latch 85 is carried in a recess 85 in the lower end portion of the stem IIJ and isl such that the lower collar 32 can be moved downwardly past it but is checked against upward movement on the stem aiter it has passed down and over the latch.

In operating the equipment that I have provided the drilling string S is equipped with one yor more safety joints or couplings C such as I have above described and when these joints are made up tight the lock linears 20 are arranged in place and the shear'pins 42 are applied to retain them in operating position as shown in Fig. 6. When it is desired to release one of the joints or couplings C the operator or operating tool that I have described is lowered into the string on the line L and as it is lowered into the string the upper collar BI of the friction means bears against the retainer i@ or the lowerrendof the body 135 so that the friction-device is pushed down through the string S or through the bores d4 that are of somewhat reduced diameter and which may occur at various points in the string. When the operator is thus lowered into the string the stem 'Ill is suspended from the head 1I supported by the retainer 'I4 so that theheadis out of engagement with the dogs 5l] which dogs will hang by gravity in a retracted position.

The operator having inserted the couplings C at predetermined points knows their location and runs the operating tool down somewhat below the joint C which is to be released. He then pulls the line up moving the operating tool up .into or beyond the coupler to. be released. When the friction device on the stem Ill moves into the bore 44 of a part I4 or the like it stops its upward movement while the rest of the tool is moved upward with. the result that the stern 'Ill moves up through the friction device until the latch 85 is engaged over the lower collar 82. This upward movement of the tool can be oontinued until the dogs 593 are somewhat above the coupler to be reduced and when suflicient movement has taken place to assure engagement of the latch over collar 82 the tool is then lowered and as it is lowered the head 'II on the stern. 16 moves up between or inside the dogs 5B and tends to spread them outwardly. If the dogs are in a part such as bore M of part I3 they cannot be spread to a full out position' but tend to move out and as the tool is lowered the dogs bear out until they come opposite the enlargement or cavity X above the lock liner Zit at which point they are moved out to the fully expanded or operating position shown in Fig. 2. Continued downward movement of the tool causes the working shoulders 68 of the dogs to engage the upper end of the lock liner 2li thus establishing operative engagement between the tool and the liner 2B as shown in Fig. 2 oi the drawings.

The liner L is then manipulated so that the jar J acts to jar .the tool downwardly and this action is made effective through the sinker bar Q6 above the jar. The downward jarring action on the lock liner shears the pin d2 and is continued until the lock liner is forced or driven down out of section II and into section I8 at which time the threaded connection between the sections I'I and I8 is freed to be released. When this has been accomplished the operatingrtool can be withdrawn and to release the threaded con'- nection between sections I'I andi@ the string S is operated or rotated in the desired direction,v

for instance, wherefthe threaded connection to be released is lefthanded the string is rotated in a righthanded direction which causes the joint to releaseor become entirely free.

A feature of the construction that I have provided is that I can provide as many safety joints or safety couplings as I desire in a single string S and I can unlock or release these joints at will by simply lowering the operating tool through the string to the desired joint and then manipulating it in the manner that I have described.

I have described the lock liner as being jarred downwardly. It will be apparent that I may reverse the arrangement so the liner is released by an upward jar,such reversal being within the alternative arrangements that are contemplated by the invention.

Having described only a typical preferred form and application of my invention, I do not wish tobe limited or restricted to the specific details herein set forth, but Wish to reserve to myself any variations or modications that may appear to those skilled in the art and fall within the scope of the following claims.

Having described my invention, I claim:

l. An elongate operator for a safety joint located ina well string and having releasably connected sections and a tubular lock part slidably engaged with the sections and located centrally in the joint, the lock part normally engaging both sections, having an upwardly facing portion, and being slidable to a position clear of one section, including, a body, means by which the body is lowered through the string and into the joint, a dog carried by the body and normally in a retracted position, and means operating the dog to an operating position projecting from the body to bear downwardly against the said upwardly facing portion of said lock part, said means including an operating head loosely coupled to the body for limited relative movement between the head and the body longitudinally of the operator, the body being movable downwardly from an elevated position'relative to the head whereby the dog engages the head and is moved thereby to the said operating position, and a holding means for the head including an element shiftable relative to the head in a direction longitudinally of the operator, a latch coupling the said element and head against relative movement upon the head being moved to a position elevated relative to said element, and a member on said element frictionally engaging the interior of the joint.

2. An elongate operator for a safety joint in a well string which joint has an opening therethrough and has a shiftable lock part with an upwardly facing upper end, the operator including, a body insertable into the opening of the joint, a dog pivotally carried by the body and normally in a retracted position, and means to operate the dog into engagement with said.V upper end of said lock part including, an operating head, a stem carrying the head and connecting the head with the body for relative movement between the body and head lengthwise of the operator, the dog being engageable with the head for operation thereby to a position where it projects from the body and opposes said upper end of the lock part, and a holding means for the stem including, a drag frictionally engaging the well string and movable relative to the stem longitudinally of the operator and engaged by the body to be pushed thereby to operating position in the well string, and a latch carried by the stein coupling the said drag and stem against relative movement upon the stem being moved to an elevated position relative to the drag.

3. An elongate operator for a safety joint in a well string which joint has an opening therethrough and has a shiftable central tubular lock part with an exposed upper end, the operator including, a body insertable into the opening of the joint from the upper end thereof, a dog pivotally carried by the body-and normally in a retracted position, and means operating the dog into an operating position projecting from the body and engageable with said upper end of said part including, an operating head, a stem carrying the head and connecting the head with the body for relative movement between the head and body longitudinally of the operator, the dog being engageable with the head to be operated thereby to the operating position, and a holding means for the stem including a friction drag slidably carried by the stem below the body and frictionally engageable with the string to yieldingly resist movement therein and engaged by the body to be pushed thereby to operating position in the well string, and a latch carried by the stem to couple the said drag and stem 8 elevated to a predetermined position relative to the drag.

4. An elongate operator for a safety joint in a well string which joint has an opening therethrough and has a shiftable tubular lock part with an exposed upper end, the operator including, a body insertable into the opening of the joint from its upper end, loosely linked elements coupled to the body for movement relative to each other longitudinally of the operator, a dog pivotally carried by the body and normally in a retracted position, and means operating the dog to an operating position engageable with said end of said part to depress said part, said means including an operating head loosely linked to the body, the dog being engageable with the head and operated thereby to the operating position upon the body being lowered relative to the head, and a friction drag shiftable relative to the head longitudinally of the operator and engaging the string and yieldingly resisting movement of the head in the string, the drag including a latch connecting the head and drag against relative movement upon the head being elevated to a predetermined position relative to the dog.

5. An elongate operator for a safety joint in a well string, which joint has a central opening therethrough and has a central tubular longitudinally shiftable lock part having an upwardly facing shoulder, the operator including, a body insertable into the opening of the joint from the upper end thereof, a jar above the body including loosely linked elements, a sinker bar above the jar and joined to one of said elements, a dog pivotally carried by the body to normally hang in a retracted position, and means to operate the dog to an operating position engageable with the shoulder of said part including, an operating head coupled with the body for relative movement between the head and body longitudinally of the operator, the body being movable relative to the head to a down position where the dog is engaged by the head and moved thereby to the operating position, and a friction drag connected with the head for relative movement between the f drag and head longitudinally of the operator, the

drag having a member frictionally engaging the well string and having a latch connecting the drag and head against relative movement upon the head being moved to a predetermined elevated position relative to the drag.

6. In combination, a safety joint for a well string including two tubular sections for application to adjoining parts of the string, threads joining the sections, and a lock liner engaged within both sections with keyed engagement therewith and shiftable lengthwise of the sections to a position removed from one section, and an elongate operating tool including a body, a dog pivotally carried by the body to normally hang in a retracted position, and means operating the dog outwardly from the body to an operating position to engage downwardly on and to operate the liner including, an operating head coupled with the body to shift relative thereto longitudinally of the operating tool, the body being movable relative to the head to a down position where the dog is engaged by the head and moved thereby to the operating position, and a friction drag connected with the head for relative movement between the drag and head longitudinally of the operator, the drag having a member frictionally engaging the well string and having a latch connecting the drag and head against relaagainst relative movement upon the stembeing l5 tive movement upon the head being moved to a predetermined elevated position relative to the drag.

7. In combination, a safety joint for a tubular well string including, two tubular sections for application to adjoining parts of the string, the sections having aligned openings therethrough for passing tools operated through the string, threads joining the sections, a tubular lock liner engaged within the sections and slidably keyed thereto to be shiftable lengthwise of the sections between a position where it is engaged with both sections and a position removed from one section, and means releasably retaining the liner in position where it engages both sections, and an elongate operating tool including, a body operable through the string and joint, a dog pivotally carried by the body and operable to an operating position where it engages downwardly on the liner, an operating head shiftable relative to the body longitudinally of the tool and engaged by the dog and moving the dog to the operating position upon the body being lowered relative to the head, the stem and body being shiftable relative to each other longitudinally of the tool, and a holding means governing movement of the stem relative to the body including, a friction device shiftable relative to the stem longitudinally of the tool and frictionally engaging the string and resisting movement of the device longitudinally of the tool and frictionally engaging the string and resisting movement of the device longitudinally in the string, the friction device being engaged by the body to be pushed down thereby to operating position in the string, and a latch carried by the stem coupling the said device and stem against relative movement upon the stem being elevated to a predetermined position relative to said device.

8. In combination, a safety joint for a tubular well string including, two tubular sections for application to adjoining parts of the string, the sections having aligned openings therethrough for passing tools operated through the string, threads joining the sections, a tubular lock liner engaged Within the sections and slidably keyed thereto be shiftable lengthwise of the sections between a position where it is engaged with both sections and a position removed from one section, and means releasably retaining the liner in position where it engages both sections, and an elongate operate tool including, a body operable through the string and joint, a jar coupled with the body and having relatively movable cooperating jar elements, a dog pivotally carried by vthe body operable to an operating position where it engages downwardly on the liner, an operating head shiftable relative to the body longitudinally of the tool and engaged by the dog and moving the dog to the operating position upon the body being lowered relative to the head, a stem carrying the head and coupled tothe body to shift relative thereto longitudinally of the tool, and a means governing movement of the stem relative to the body including, a friction device having an element frictionally engaging the string and resisting movement of the device in the string, the friction device being engaged by the body -to be pushed down thereby to operating position in the string, and a latch carried by the stem coupling the said device and stem against relative movement upon the stern being elevated to a predetermined position relative to said device.

9. In combination, a safety joint for a tubular well string including, two tubular sections for application to adjoining parts of the string, the sections having aligned openings therethrough for passing tools operated through the string, threads joining the sections, a tubular lock liner engaged within both sectionsand keyed thereto to be shiftable lengthwise of the sections to a position removed from one sectionI and means releasably retaining the liner in position where it engages both sections, and an elongate operating tool including, a body operable through the string and joint, a jar coupled with the body and having relatively movable cooperating jar elements, a sinker bar above the jar and coupled to one of said jar elements, a dog pivotally carried vby the -body operable to an operating position where it engages downwardly on the liner, an operating head coupled with the body for relative movement between the body and head longitudinally of the tool and adapted to be engaged by the dog and to move the dog to operating position upon the body being moved down relative to the head, a stem carrying the head and slidably carried by the body, and a means governing movement of the stem relative to the body including, a friction device movable relative to the stem longitudinally of the tool and having a drag element frictionally engaging the string and resisting movement relative to the string, the said means being engaged by the body to be pus-hed down thereby to operating position in the string, and a latch carried by the stem coupling the said device and stem against relative movement upon the stem being elevated to a predetermined position relative to said device.

10. An elongate operator for a safety joint located in a well string and having a shiftable tubular lock part located centrally in the joint including, a body, means by which the body is lowered through the string and into the joint, a dog carried by the body to shift between a retracted position and an operating position where it engages downwardly on and operates the lock part, and means operating the dog to the projecting position including, an operating head coupled to the body to shift relative thereto longitudinally of the operator and engaged by the dog to move it to the operating position upon the body being moved to a down position relative to the head, a friction member engaging the interior of the joint to resist movement longitudinally therein and carried by the head for movement relative thereto longitudinally of the operator, and a latch connecting the head and said member against said relative movement upon the head being moved to a predetermined up position relative to the said member, the dog being pivotally mounted and normally held by gravity in the retracted position.

THOMAS A. CREIGHTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,778,830 Irvine Oct. 21, 1930 1,801,334 Dallorf et a1 Apr. 21, 1931 1,883,071 Stone l Oct. 18, 1932 2,108,971 Olsen et al Feb. 22, 1938 2,153,812V Newton Apr. 11, 1939 2,210,815 Linney Aug. 6, 1940 2,302,856 Hamon NOV. 24, 1942

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