US2678101A - Bridging plug and setting tool - Google Patents

Description

May l1, 1954 c. THAxToN 2,678,101

4 BRIDGING, PLUG AND SETTING TooL Filed May 8. 1948 2 Sheets-Sheet l 1. i if?. 2.

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IQTTOQNEY.

May 1l, 1954 l.. c. THAxToN BRIDGING PLUG AND SETTING TOOL 2 Sheets-Sheet 2 Filed May 8. 1948 Patented May 11, 1954 OFFICE BRIDGING PLUG AND SETTING TOOL Luther C. Thaxton, Casper, Wyo., assignor to Lane-Wells Company, Los Angeles, Calif., a

corporation of Delaware Application May 8, 1948, Serial No. 25,925

1 Claim.

This invention relates generally to well packing devices and more particularly to bridging plugs and tools for setting bridging plugs and the like devices within well boreholes and casings.

Packer devices particularly of the bridging plug type are usually employed for the well known purpose of closing or sealing off a. lower' portion of the well or to separate upper and lower sections thereof for various purposes. Such` bridging or plugging operations are often employed, for example, when a lower zone in an oil Well has ceased to be sufciently productive, or Where the well bore has been found to extend into water-producing zones or thief sands, or for any other reason it becomes desirable to plug back or close-off a lower zone or portion of the well and produce from a higher zone in the well. In some such cases where the bottom Zone into which a well has been drilled fails or ceases to be sufficiently productive, it may then be desirable to explore and test a number of higher zones for their possible productivity.

Under such conditions it is the usual practice rst to position and set a bridging plug in the well at a point a short distance above the top of the lowermost Zone or portion of the well bore to be sealed 01T and then to test another prospective zone intersecting the Well above the set bridging plug. If the second zone also proves to be unproductive another bridging plug may be set in the well bore above the top of the second zone thus tested and another test made. This testing process may be repeated step by step at successively higher zones as many times as is desired.

Heretofore the process and apparatus required for lowering, positioning and setting a packer in the well and for releasing the setting tools has been more complicated, expensive and timeconsuming than is desirable, particularly under such conditions as heretofore mentioned where a relatively large number of bridging plugs must be set throughout a considerable length of the well. Furthermore, the setting of bridging plugs has usually required that special servicing, hoisting and control equipment be employed other than those available as standard equipment about a drilling and producing well. This latter situation has heretofore resulted in substantial limitations and restrictions in the use of bridging plugs in wells particularly in remote parts of the world where the special service facilities and skills desirable for such operations are usually unavailable.

It is, accordingly, an object of this invention to provide bridging plug and setting too1 appae ratus which will eliminate many of the undesirable and limiting features heretofore prevalent in bridging plug and setting tool operations and apparatus.

it is also an object to provide a bridging plug and setting tool therefor, of novel construction and which is simple, inexpensive and dependable and capable of rapid and eiiicient operation.

t is also an object of this invention to provide improved wel] bridging plug apparatus which may be serviced and set in a well without the use oi any equipment other than that always present standard equipment in the drilling, producing 1 or maintenance of wells.

rIhe objects of the invention are accomplished, in general, by a novel setting tool and combinar tion of setting tool and packer device which may be run to the desired depth, set and released in set condition in a well on and by use, preferably, of a cable such as a sand line or that used in. standard cable tools, all without requiring any equipment or personnel other than those usually available for or during the drilling, production or maintenance operations of a well.

rIhese and other objects, advantages and features of novelty will be evident hereinafter.

In the drawings which show by way of illustration, preferred embodiments of the invention, and in which like reference characters designate the same or similar parts throughout the several views:

Figure l is a longitudinal elevational view of the general assembly of the bridging plug and setting tool as it appears when assembled ready to be lowered into a well or when suspended within a well casing just prior to setting.

Figures 2 and 2a are enlarged fragmentary longitudinal sectional views of adjoining upper and lower portions respectively of the apparatus of Figure 1 showing its assembled appearance while being lowered and just prior to .setting in a casing.

Figures 3 and 3a are longitudinal sectional views of adjoining upper and lower portions respectively of the apparatus showing its appearance just after completion of the setting stage.

Figure 4 is a longitudinal sectional View oi a fragmentary portion of the upper end of the bridging plug mandrel and a lower end portion of the setting tool strut connections showing their appearance just after disconnection from one ano-ther following the completion of the setting stage as illustrated in Figure 4.

Figure is an enlarged cross-sectional viewl dinal sectional view taken on line 5-6 of Figure 5.

VThe apparatus is as follows:

Referring now to the drawings and primarily to Figure 2a, the packer portion or body of the apparatus-:comprises a centrally located, elongated tubular body or mandrel I3 of substantially uniform external diameter throughout its length and closed and terminating at its lower end by a nose piece or shoe portion II of slightly increased diameter, an upwardly facing annular shoulder I2 being thus formed at the junction of said mandrel body and said shoe portion. A plug 22 threaded into the bottom of the shoe I l closes a threaded connection which may be employed for attachment of other apparatus such as, for example, a lower string of tubing or a circulatingY valve not shown.V At the lower intermediate portion, the mandrel is formed with a short section I3 of slightly reduced diameter about which a split ring I4 is placed and is therein longitudinally slidably retained to act as a means for retaining. an annular packing body 3T in place upon the mandrel as, more fully described hereinafter. At an upper intermediate portion, the mandrel is formed with a length of downwardly facing ratchet grooves or buttress threads i3 adapted to ratchet through and make one-way locking engagement with a correspondingly toothed split, lock ring I7. The lock ring il is retained in an inwardly facing, annular groove formed between upper and lower, threadedly interconnected halves I8 and I9 respectively of a lock ring adapter fitting 23 hereinafter also more fully. described. A shallow annular groove 2i is formed in the upper portion of the mandrel I8 adjacent the upper end thereof which serves as a detent tovreceive-the inner toothed portion of the lock ring I'i when the packer is in the unset condition as-illustrated in Figures 2 and 2a.

The upper end of the mandrel IIB is provided with internal threads 23 into which a relatively short, externally threaded connector sleeve 2d is screwed.

A plurality of lower, wedge shaped slips 25 having, downwardly facing serrations or wickers are normally positioned about the lower end of the mandrel IiiA as shown in Figure 2a, and retained there by a slip retainer ring 26, attachment betweeneach of said sl-ips and said retainer ring being effected by a dove-tail interconnection comprising a radially directed dove-tailslot Z'Iformed in the upper face of the retainer ring 25 into which a dove-tail 28 formed on the lower base end of the slip, ts and has limited freedom for radial sliding motion therein to permit radial expansion of the slip.

A like set of upper slips 32 having upwardly facing serrations is` provided about the upper portion of the mandrel IB adjacent the lower end of the beforementioned lock ring adapter iitting 2.0 and these slips are similarly provided with dove-tail connections as shown at 33 to the lower half I9 of the lock ring adapter fitting 2) permitting radial expansive movement of said slips.

Intermediate the beforementioned sets of upper and lower slips are a lower, upwardly diverging slip cone 35, an upper, downwardly diverging slip cone 36 and a resilient, sleeve shaped packing element 3l intermediate the said slip cones, all longitudinally slidalbly retained upon the mandrel III except as initially restricted by various releasable interconnecting means hereafter described. The upwardly facing base end 38 of the lower slip cone 35 and the downwardly facing base end 39 of the upper slip cone 33 serve as lower and upper abutments respectively between which the resilient packer element 31 is retained and in operation is adapted to be compressed longitudinally for deformation or expansion radially into sealing engagement with a surrounding borehole wall or casing.

The bore. of the packing sleeve 31 is formed with an inner annular groove 43 adjacent its lower end to receive the outer portion of the hereinbefore mentioned retaining ring I4. The ring |41 is usually, although not necessarily, placed in the packer body at the time of its manufacture and thus may be rmly bonded thereto to form a unitary part thereof. Y

Each of the lower slips 25 is provided with a positioning pin fixed therein as shown at 4I, having its inner end extending with a relatively loose t into a shallow socket formed in the mandrel as shown at 42. E'ach of the slips of both the upper and lower set of Vslips is initially anchored to the slip cone face upon which it bears, by means of a shear pin or screw as shown respectively at 43 and M.

IThe lower set of slips 25 is urged upwardly by means of a plurality of coil springs 45 retained in circumferentially spaced holes extending axially through the flanged or shouldered portion i2 of the nose piece II and acting under compression between the lower face of the slip-retainer ring 26 and threaded, spring-retainer plugs 46.

The lower packer-abutting end 33 of the upper slip cone 36 is formed with a short counterbo-re 48 terminating at its inner upper end in a chamber or upwardly converging conical shoulder 53. The lower end portion of the slip cone outside of the beforementioned counterbore, is formed with a downwardly converging conical surface as shown at 5G, terminating at the intersectionl of its conical surface with the inside cylindrical surface of the counterbore 118, in a downwardly directed, relatively sharp beveled edge 52. The upper adjacent end of the resilient packing sleeve 3l is formed with an outer conical end portion adapted toiit and normally abut the before-described conical surface 53 of the slip cone 33. The packing sleeve is also provided with a longitudinally directed cylindrical slit 55, commencing at the inner terminus of the conical surface 53 of the packer and extending longitudinally inward or downward for a short distance along a cylindrical surface formed by the downward projection of the inside cylindrical surface of the slip cone counterbore 5S. A pair of separate, concentric, annular portions of the upper end of the packing 37l are thus formed, separated by the slit 55, the inner annular portion 555v being adapted to be thrust intothe inner annular space within the counterbore 48 around the packer mandrel and the `outer annular portion 5l being adapted to be thrust into the outer annular space formed between the outside surface of the lower end portion of the slip cone 36 and the inside surface of a surrounding casing asshown in Figure 3a, upon application of longitudinal compressive force to the packing sleeve 3l. overlapping ends of the slips 32. serve toY seal ofi the upper end of this annular spaceinto which the packer is thrust as shown in Figure 3a;

Referring now primarily tofFigure 2, in which The lower the upper, setting tool portion of the packer apparatus is illustrated, a tubular adapter sleeve 60 is shown extending upwardly from a threaded connection 6I located at the top of the locking ring adapter fitting 20. Upon the top end of the adapter sleeve 6l) is an auxiliary, well bore wall or casing gripping means comprising a dog retainer head 62 formed with an axial bore 83. The dog retainer head 52 is formed with two pairs of diametrally opposite, radial slots ft, 64a and S5 and 65a extending downward through the annular top portion of the head as best shown in Figures 2 and 5. Each slot contains a carnshaped gripping member or dog 86 pivotally supported therein adjacent its lower end upon a pin connection 61 which extends cross--wise through the lower part of the slot. The upper, cam-shaped, free end of each dog 66 is provided with serrations as shown at 68 and the outer side thereof is provided with a longitudinal groove or recess E9 into which the top portion of a helical spring 10 normally extends to a pin connection 1I therein as shown in Figures 2, 3 and 6. The opposite or lower end of each of the springs lo extends downwardly through a longitudinal slot 12 formed in the exterior surface of the head 62 to a suitable fastening to the head in the lower portion of the slot as shown at 13. The springs 1G acting in tension urge the dogs 68 to pivot outwardly about their pivot pins 61 to extended positions as shown in Figures 2, 3, 5 and 6.

It is to be noted that the general curvature of the upper or outer serrated ends or" the dogs Sii opposite their pivots 61 are eccentric to the pivots, or cam-shaped, to adapt them to rock into nrm gripping engagement with the inside surface of a casing or borehole wall upon imparting upward movement to the apparatus relative to such casing or borehole.

A setting sleeve 11 having an upper tubular shank portion 18 of larger diameter than the lower tubular strut portion 18 is normally positioned, as initially assembled, with the shoulder si?, formed at the juncture of said shank and said strut, resting upon the slotted, annular, top end surface of the dog retainer head S2 as shown in Figures 1, 2 and 6. The upper end of the setting sleeve shank 18 is provided with suitable external threads 8l adapted to make screwed connection with a cable or so-called rope socket 82 l suspended from a cable 83 as illustrated in Figures l and 2 when the apparatus is run into the well and set on a cable. Adjustably threaded into internal threads formed in the lower end of the strut portion 19 of the setting sleeve'l1 is a short, externally threaded connector member 84, the lowermost unthreaded end portion of which extends into the top opening of the beforementioned connector sleeve 24' and is secured there by means of a shear pin 84a which extends crosswise through holes drilled through both the connector sleeve 24 and the connector member 84. An adjusting nut 85 and lock nut 86 carried on the lower threaded portion of the connector member 8d serve by proper adjustment against the top of the connector sleeve 24 to relieve or protect the shear pin 84a from any downward thrust or compression forceswhich may be applied through the setting sleeve. A lock nut 81 carried on the intermediate, threaded portion of the connector member 84 serves to secure the adjusted position of the connector member within the lower end of the setting sleeve strut 19.

A shear pin 9B making a driving t through a drilled hole in the lower end portion of the adapter sleeve 60 extends into an aligned, drilled hole or socket formed in the upper end of the mandrel i0. The shear pin 96 serves as a means for initially positioning and locking the packer mandrel relative to the setting mechanism and to support the weight of the sleeve 60 and head 62 which might otherwise tend to force the upper slips and slip cone 36 downward against the packer sleeve 31 and thus tend to cause premature setting of the packer.

Upper and lower, lateral fluid pressure equalization and circulation openings and lill are provided through the walls of the shank and strut portions respectively of the setting sleeve 11.

The operation is as follows:

In running in and setting the bridging plug apparatus of this invention the combined bridging plug and setting tool are assembled as shown in Figure l and lowered into the borehole or casing upon a cable 83 to the point at which it is desired to bridge the well.

As the apparatus is lowered into the casing on the cable, the dogs B will merely drag in trailing attitude along the inside surface of the casing without aording any substantial resistance to the downward motion. However, upon arriving at the position at which it is desired to set the bridging plug and upon stopping the downward motion and applying upward tension through the cable tending to elevate the apparatus, the dogs being already positioned in the beforementioned extended and trailing attitude will immediately cramp or rock outward into lock;- ing engagement with the inside surface of the casing and resist upward motion of the dog retainer head 64.

The upward tension thus applied to the cable is transmitted through the setting sleeve 11, the connector' member 84 and thence through the shear pin 84a and the connector sleeve 211 to top of the bridging plug mandrel il). The upward force thus applied to the bridging plug mandrel i0 tends to move the said mandrel lil upward with respect to the dog retainer head 62 and adapter sleeve 60 to a position such as that illustrated in Figure 3. However, shear pin 9S initially resists such relative motion until the upward force applied to the mandrel I0 reaches the shearing strength of the pin 86. Upon shearing of the pin 98 the upward force thus applied to the bridging plug mandrel l0 is rather suddenly transferred downward through the lower portion of the mandrel to the nose or shoe il and from there is transmitted upward from the shoulder l2 of the nose or shoe il through the bottom slip retainer ring 26, lower slips 25, shear pin or screw 43, lower slip cone 35, packing element til', upper slip cone 36, shear pin or screw dit, upper slips 32, and thence through the lock ring adapter fitting E8 and the adapter sleeve 8i! to the dog retainer head E2 and thence finally through the dogs 65 to the casing. The force thus applied after rst shearing the positioning pin 9B next results in shearing of the slip shear pins or shear screws 43 and 44 thereby permitting the upper and lower slips 32 and 25 to move outward upon the surface of their respective slip cones 36 and 35 into gripping engagement with the inside surface of the well casing. Following this and upon further application of upward force through the mandrel I8 the slip cone 35 is caused to move upward relative to the slip cone 3B a distance sufcient to laterally compress and radially expand the resilient or deformable packing sleeve 31 into sealing engagement with the inside surwardrelative to the lock ring adapter yfitting 26' a distanoesunicient vto carry the ratchet grooves or ibuttress threads LIS of .the mandrel Vupward through and rinto locking vengagement with the lock .ring H. Thebridging plug is thereby locked in the set condition within the ycasing with both the .upper and the lower. setsotslips in holdingrengagement with theinside surface of thecasing as shown in Figures .3 and 3a. Y

After setting the apparatus Yin .the .casing as hereinbefore described :continued `and increased upward force is applied through .the .cable '.83 and the settingsleeve 'llnnally resulting in the shearing of the shear rpinlol .thereby .resulting -in the disconnectionand separation oi the setting sleeve 'il and the connector .member 84 from .the connector sleeve 2li in the manner illustrated :in Figure 4. If desired .a set of jarsmay be 'placed immediately above :the setting .tool to facilitate this latter disconnecting operation. The portion of the setting tool remaining `connected to vthe cable B3 including thesocket 82,'the'setting sleeve ll and with the .connector member 855 attached, may then be withdrawn from .the well casing. The several retainer members, :shear pins and screws hereinbeore mentioned are designed to shear in the order named, namely, first pin 96, followed by screws 43 and @il ,and finally pins Ba. Normally pins il are not sheared but merely Amove outward laterally with the lateral motion of the slips 25, thereby .simply withdrawing the inner ends of the pins from the sockets '42 `in the mandrel. The .pins li iserve, vprior to `settingr of the packer to hold the slips -25 `rr-ztracted and bottom against the shoe shoulder .l2 against ythe upward force of ycoil springs e5. The force of the coilsprings 45 is thus .prevented `from being applied against the bottom of the Vpacking sleeve 3i which might .otherwise result `in premature setting of the packing during lowering=of the device into the well.

Ordinarily the lower vslips 2,6 and their retaining ring26 remain,.bef.ere and after setting, bottomed Y upon the upper surface of the'shoulder i2 of the shoe l l. However, in event .movement of the plug should occur after .setting such that the resultant relative Vmotion between the lower slip cene 35 and the shoulder I2 tended lto release the lower slips 25, then the coil springs 45 would force the said slips to follow any such motion of the slip cone in wedging position between the slope of the cone and the inside surface of the surrounding casing.

While the apparatus and operation of this invention has been described .as advantageously be employed in some rcases in connection with a cablesupporting and'lowering means, itmay also be employed in .some .cases in .connection :with a suitabletubing string or pipe.

It is to be understood that `.the foregoing :is illustrative only vand that the invention is not limited therebybutmay include various modifica tions and changes .made by'those skilled inthe art without distinguishing from the spirit and scope of the invention as .defined in the appended claim.

I claim:

A bridging plugsetting'toolfor setting a bridge ing plug, which bridging plug includes a mandrel, an annular packing body surrounding vthe man drel, upper and lower slips above and below packing body respectively, an Aupwardly facing shoulder on said mandrel fbelow sai'd lower slips, and an adapter fitting surrounding said mandrel above said upper slips .and having a .downwardly facing shoulder, suchbridging plug'being adapted .to be set by upward movement of the imandrel relative to the adapter fitting, said setting `tool comprising a ytubular `adapter .sleeve .secured to and extending upwardly .from said adapter fitting, upwardly and outwardly extending gripping dogs pivotally mounted in said tubular `adapter sleeve for pivotal movement in .vertical planes,

said gripping dogs being biased'toward outwardly extended positions whereby said .gripping .dogs

`permit free downward movement of said tubular adapter sleeve through a'surrounding well casing but engage and grip such .easing lto prevent up ward movement of said tubular .adapter sleeve therein, a setting sleeve removably extending in telescoping relation l-into the upper end of said tubular adapter sleeve, a frangible connection between the lower end of `said setting sleeve and the upper end of said mandrel, wand means for attaching a cable to the upper `end .of said setting sleeve for applying an upward forceto said setting sleeve while said gripping dogs .prevent upward movement of said tubular adapter sleeve to move the upwardly facing shoulder on'said mandrel upwardly toward said downwardly facing shoulder on said adapter tting to thereby setV the bridging plug and to subsequently break with Vsaid frangible connection to permit removal of said setting sleeve from the well.

References Cited in the le lof this patent UNITED STATES PATENTS

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