US2675876A

US2675876A - High-pressure well packer

Info

Publication number: US2675876A
Application number: US137056A
Authority: US
Inventors: Martin B Conrad; Jr Earnest H Clark
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1950-01-06
Filing date: 1950-01-06
Publication date: 1954-04-20
Anticipated expiration: 1971-04-20

Description

April 20, 1954 M. B. coNRD ETAL HIGH- PRESSURE WELL. PACKER 5 Sheets-Sheet l Filed Jan. 6, 1950 TTEMEKS M. B. CONRAD ETAL 2,675,876

HIGH-PRESSURE WELL PACKER '3 Sheets-Sheet 2 .April 2o, 1954 med Jan. e.I 195o Twe/VEYJ April 2Q, 1954 M. B. CONRAD ETAL 2,675,876

HIGH-PRESSURE WELL PACKER Filed Jan. 6, 1950 3 Sheets-Sheet 3 .QTToeA/Exs Patented Apr. 20, 1954 HIGH-PRESSURE WELL PACKER Martin B. Conrad and Earnest H. Clark, Jr., Huntington Park, Calif., assignors to Baker Oil Tools, Inc., Vernon, Calif., a corporation of California Application January 6, 1950,*Seral No. 137,056

25 Claims. 1

The present invention relates to well packers, and more particularly to packers useful in subjecting well formations to fluid pressures that might be of a comparatively high order.

Well formations may be subjected to comparatively high pressures, which may be in excess of 8,000 p. s. i. As an example, the formation at a predetermined depth in the well bore is to be fractured hydraulically by pumping a particular fluid medium into it under high pressures. Difficulties have heretofore been encountered in providing subsurface equipment that can be run in the well casing and be capable of withstanding and delivering such high pressures to the formation. This is especially true of well packers of the retrievable type which are to straddle the perforations in the well casing. Such straddle tools should be capable of localizing the hydraulic pressure to a comparatively small region at any one time, and, if the longitudinal extent of perforations in the casing is large, to pressurize progressively the formation from the bottom of the casing perforations upwardly.

Accordingly, an object of the invention is to provide a well packer mechanism capable of straddling casing and similar perforations and of directing and localizing comparatively high fluid pressures on the formation behind the casing.

Another object of the invention is to provide a well packer mechanism capable of straddling some of an extended length of perforations in the well casing, and ofV directing uid pressure through the straddled perforations, without subjecting the casing itself to such fluid pressure. More particularly, the casing above the perforations is not subjected tothe fluid pressure.

Another object of the invention is to provide a well packer mechanism embodying retractible and expansible packing elements adapted to be located on opposite sides of casing perforations, and capable of remaining in packed-off condition against the well casing while being subjected to very high vfluid pressures.

A further object of the invention is to provide a Well packer mechanism embodying packing elements that can be selectively expanded or retracted against and from a well casing, to enable the packer to'be set, as desired, on opposite sides of casing perforations. Because of this capability,

the mechanism can be utilized in progressively pressurizing the formation in step-by-step fashion `from the bottom oigan extended length of the casing perforations in an upward direction.

Still another object of the invention is to provide a well packer embodying a normally retracted packing which is outwardly expandible against the Well casing by compressing the packing in the longitudinal direction, and which is held in leakproof relation against the casing despite longitudinal movement of well packer parts which would ordinarily tend to loosen the packing.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of several forms in which it may be embodied. Such forms are shown in the drawings accompanying and forming part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figures 1, 1a and 1o together constitute a longitudinal section through a well packer apparatus disposed in a Well casing, Fig. 1a constituting a lower continuation of Fig. 1, and Fig. 1b constituting a lower continuation of Fig. 1a;

Figs. 2, 2a and l2b are views similar to Figs. 1, 1a and 1b, respectively, disclosing the packer anchored in packed-off condition against the- Well casing;

Fig. 3 is a side elevation, on a reduced scale, illustrating the well packer apparatus in retracted position within a well casing;

Fig. i is an enlarged longitudinal section of the lowermost packing structure in packed-ofi condition;

Fig; 5 is a cross-section taken along the line 5--5 on Fig. 1; t' Y Fig. 6 is a longitudinal section through a modiiied form of the lowermost portion of the tool.

The well packer apparatus A disclosed in the drawings is particularly designed for forcing fluids under high pressures through perforations P in a well casing B, in order to subject the formation behind the perforated region of the wellcasing to suchy pressures, and thereby effect its fracture. The equipment can be used for forcing fluid under pressure through an extended length of perforations P in the well casing by selectively setting and releasing the packer A with respect to the casing B. Thus, the packer may be caused to localize a small zone in the casing atthe bottom of the perforations and then v force fluids under pressure through such perforations. The tool may then be released and moved to a higher elevation, where it can be set, and iluid under pressure forced outwardly through the next higher perforations. Progressive setting, pressuring and release of the packer may take place in upward sequence along the perforations, until the entire length of formation opposite the perforations P has been subjected to pressure.

During the above operation, the casing above its perforated portion does not have pressure imposed upon it. As a result, bursting of the casing B under high pressures is avoided.

The apparatus can be run in the well casing on the lower end of a tubular string (not shown) extending to the top of the well bore. The central mandrel or body IU of the tool is secured to this tubular string. This mandrel or body is tubular, to provide a passage extending through it, that is communicable with the tubing string.

The packer body SQ includes an upper portion ll attached to the tubular string, the lower end of this upper portion being threaded, by means of a right-hand threaded connection, into a safety collar i2, which is, in turn, threaded onto a lower mandrel or body portion i3 by means of a left-hand threaded connection M. The lower mandrel i3, in turn, is threaded into an intermediate coupling l5 that is threaded onto the upper end of a mandrel or body extension l5 having its lower end threaded into the box portion Il of the lowermost packer body I3. All of the threaded connections are preferably righthand ones except the safety joint 4, which is left-hand, to enable the upper body section il and safety collar to be unscrewed from the lower mandrel I3 whenever difficulty is encountered in retrieving the tool from the well casing, as explained below.

The well packer A is adapted to be anchored to the casing B against upward movement. It is provided with longitudinally spaced packing structures I9, 2t, 2l, that are normally in re* tracted position, but which are adapted to be expanded outwardly against the well casing B, as on opposite sides of the casing perforations P, to establish a localized pressure zone or region in the well casing through which fluid under pressure may be forced, for passage through the perforations P and into the formation.

In order to anchor the tool in the Well casing, its upper portion is provided with an anchoring device of the type disclosed in United States Patent No. 2,368,401. This device includes an expander member 22 slidable relatively along the upper mandrel or body li, and having tapered surfaces 23 cooperable with companion tapered slips 24. These slips have wickers or teeth 25 facing in an upward direction, and designed to dig into the casing wall, for the purpose of preventing upward movement of the well packer therewithin.

The slips 24 are movable jointly along the expander 22, to and from an expanded position against the casing wall, by pin-connecting them to the lower ends of links 25. The upper ends of the links have transversely extending pins 2'! receivable within a coupling or slip sleeve 2, that is connected, by means of a swivel 2Q, to a friction drag and lock device Sil. This latter device includes a lower collar 3l slidable along the uppermandrel il, with a lower annular nut 32 threaded into the collar, and having an ex.- ternal flange 33 received within an inner circular groove 34 in a two-part ring 35, the two parts of the ring being suitably held together by an encompassing sleeve 36. Also received within the ring 35 below the annular nut flange 33 is an external flange 3l extending from the upper end of the coupling sleeve 28.

The lower ends of a plurality of outwardly bowed springs 33 are suitably secured to the lower drag collar 3i, the upper ends of such springs heilig secured to an upper drag collar 3S slidable relatively along the upper mandrel Il.

The springs 38 frictionally engage the casing B, and tend to resist longitudinal movement of the slips 2d therewithin in bothdirections. When the slips are to be se-t, the mandrel IU is moved upwardly, which moves the slip expander 22 upwardly (through parts to be described hereinafter) within the slips 2li, urging the latter radially outward against the casing B, because of the cooperating

tapered surfaces

23, 23a on the expander and the slips. The slips 24 cannot move longitudinally, when unlocked from the mandrel i, because of the resistance to movement offered by the springs 38 against the i casing B.

r lock device may be of the type described in the above referred to patent. It includes a split ratchet ring Ai! having an external surface 4i tapering in an upward direction for engagement with a companion internal surface 4.2 in the lower drag collar. Ratchet teeth '33 facing in a downward direction are provided in the ring t for cooperation with companion upwardly facing ratchet teeth rid on the periphery of the mandrel I.

It is apparent that any tendency for the mandrel I0 to move upwardly causes its teeth it to engage the ratchet teeth $3 .in thg split ring tt, and, in view of the wedging engagement of the ring in the collar 3i, couples the latter to the mandrel I, which also couples the slips 2i to the mandrel and prevents relative longitudinal movement between them. Of course, the mandrel can move freely in a downward direction within the ratchet ring lli?, in view of the slope of the peripheral faces on the ratchet teeth 44, 3.

The ratchet lock ring 4Q may be rendered in effective by moving the mandrel lo angularly, which will expand the ring 49 away from the mandrel teeth 45;, allowing the mandrel to move upwardly within the lock ring and the lower drag collar 3|, as explained in the above United States Patent No. 2,368,401.

The slip expander 22 has a depending extension 45 threaded on its lower end, which is provided with perforations or longitudinal slots 4'5. This extension, in turn, is threaded onto an upper abutment 4l disposed immediately below the safety collar I2. This abutment il is spaced outwardly of the lower mandrel or body I3 to provide an annular space 138 in which an upper packing compression sleeve 49 of the upper packlng structure I may move. This compression sleeve-19 is slidable relatively along the lower mandrel t3 and has an outwardly directed flange "in integrar therewith. #The gnange' 'isl provided form a lower support for a packing sleeve 52, ofk

natural or synthetic rubber, which encompasses the compression sleeve 49. The upper end of the packing sleeve 52 engages the upper abutment 41. When the compression sleeve 49 is moved in an upward direction toward the upper abutment 41, the upper packing sleeve 52 isV foreshortened and compressed, being expanded outwardly against the casing wall. Y

A skirt 53 depends from the iiange portion 58 of the upper compression sleeve 49, and is threaded onto a lower compression sleeve 54 that may have perforations 55 near its upper end. This lower compression sleeve 54 extends downwardly along the lower mandrel or body I 3 and is threaded'into a coupling collar 56 adjacent the intermediate coupling l between the lower mandrel I3 and the mandrel extension I6. A compression sleeve extension 51 is also threaded into the'coupling collar 56. and depends along the mandrel extension I6 to substantially the same lower point as the latter, terminating adjacent the lowermost body box I1, where it is ythreaded into a lower coupling 58 fitting loosely around an abutment member 59 laterally spaced from the lowermost body I8, to form an annular space 59 in which the upper end of another packing compression sleeve 5I is movable. This compression sleeve 5I is slidable longitudinally along the lowermost body member I8. The abutment member 59 may originally engage a shoulder 62 on the box portion I1 of thelowermost body I8, and it may also be provided with perforations 63 to prevent fluid from being entrapped within the annular clearance space 68 between the abutment and the lowermost body.

, The abutment may have a gauge ring 84 threaded on it to increase its maximum external diameter. An intermediate packing sleeve 65 of rubber or similar material is disposed around the compression sleeve 6 I, with its upper end engageable with the abutment 59 and gauge ring 64, and its lower end resting upon a ange 66, integral with the compression sleeve 5I, and on which a gauge ring 81 may also be threadedly mounted. The

parts

59, 6i, 84, 65, 66, 61 together constitute the intermediate packing structure 20.

The flange 66 rests upon a spacer sleeve 68 having perforations 69, the lower end of which bears against the liange portion 1U of a lower packing compression sleeve 1I slidable relatively along the lowermost body or mandrel portion I8. This compression sleeve 1I is movable with- -in the annular clearance space 12 formed between the body I8 and an adjusting nut and guide 13 threaded on the lower end of the mandrel. This adjusting nut and guide also has perforations 'I4 through its wall to permit fluid to iiow in and out of the annular space 12. It also possesses a gauge ring which increases the effective outside diameter of the adjusting nut or abutment 13. 'Ihe lower end of a lowermost rubber packing sleeve 16 rests upon the lowermost abutment 13 and gauge ring 15, the packing sleeve 18 encompassing the compression sleeve 1I, with its upperl end being disposed adjacent the iiange 19, on which a gauge `ring 'I1 is threaded. The parts 10-11 together constitute the lower packing structure 2l. Y f v"'.Ihe tubular mandrel or body sections I i; I3,` i5,

`I8have a passage 18 therein which may terminate in' the lowermost mandrel portion I8. Leakage from the passage 18 is prevented by providing suitable thread seals 19 at each threaded connection between the various mandrel elements. The mandrel passage 1B communicates with the annular space 88 within the lower spacer sleeve 68 through' a plurality of mandrelports 8|, fluid within the mandrel being capable of passing outwardly through the mandrel ports 8| and through the ports or perforations 89 in the spacer sleeve into the region 82 between the intermediate and lower packing structures 28, 2|.

In order to prevent leakage of this uid through the interior of the packing

sleeves

55, 16, the compression sleeves 6I, 1I, on which the latter'are mounted, are provided with suitable side seals`83, such as rubber 0 rings, disposed in suitable grooves 84 and slidably and sealingly engaging the exterior of the lowermost mandrel member I8. When the two lower

elastic packing sleeves

65, 18 are foreshortened and compressed outwardly against the wall of the casing B, they form the localized zone 82, into which fluid from the mandrel can be pumped under very high pressure, for outward passage through the casing perforations P and into the formation.

It is also desired that fluid be prevented from passing along the exterior of the mandrel within the uppermost elastic packing structure I9. For this reason, the upper compression sleeve 49 may be provided with a suitable side seal 85 sealingly engageable with the exterior of the mandrel I3. When the upper packing 52 has been foreshortened and compressed against the well casing, fluid is prevented from passing around this packing.

It is preferred to employ the threaded and replaceable gauge rings 5I, 64, 61, 11, 15 on the abutment and compression sleeve members, so as to hold the-clearance spacebetween the gauge rings and the casing wall to as low a value as is practical, thereby minimizing the opportunity for cold owing of the rubber packing material through such clearance space when the packing elements are subjected to high pressures. A suitable outside diameter gauge ring is selected, depending upon the inside diameter of the casing string in which the tool is to be anchored in packed-off condition.

The apparatus is assembled and is run'in the well casing with the 'slips 24 and the various packing sleeves 52, B5', 16 in retracted positions, and with the parts occupying the relationship illustrated in Figs. 1, la and 1b, and Fig. 3. During lowering through the well casing B, the friction drag springs 38-tend to resist downward movement of the slips 24.- However, the mandrel I8 may ratchet freely in a downward direction through the lock ring v48, its downward movement being limited by engagement of the safety collar I2 with the upper abutment' 41. Since this upper abutment is connected to the expander extension 45, the downward movement and force is transmitted to the slip expander 22, urging the latter downwardly ofthe slips 24 and holding the latter in an inward position, in view of the dove-tail connection 86 between the expander 22 and slips 24. The slips 24, through their connected links 28 and swivel connection 29, pull downwardlyon the lower drag collar 3 I, and slide the friction springs 53 along the casing wall.

The adjustingrnut and .guide 13 Aalsornoves downwardly with the mandrel I9, since it is attached to it. The various packing members and compression sleeves, in effect, float between the uppermost abutment 41 and the adjusting nut guide 13, since there is nothing tending to compress and foreshorten the

sleeves

52, 65, 16 during downward movement of the tool. That is, all of the packing rubber elements remain in their normal, inherently retracted positions during lowering of the tool A in the well casing B.

In the event that the well casing B has an lextended length of perforations P, it is desired to locate the

lower packing sleeves

65, 16 on opposite sides of the lowermost group of perforations, so as to localize the application of pressure through these perforations. The uppermost packing sleeve 52 is to be expanded against an imperforate casing portion R above the perforations P for the purpose of preventing the pressure from being imposed on the interior of the casing B.

The spacer sleeve 68 beween the two lower packing structures 2S, 2| is of such length as to subtend a predetermined length of perfor-ations P. The distance between the intermediate packing sleeve 65 and the uppermost packing sleeve l52 should be selected so that the uppermost packing sleeve will be packed off against the imperforate casing section R. This necessary distance is obtainable merely by coupling mandrel extension members I6 to one another of the desired length between the intermediate coupling I5 and the threaded box I1 of the lowermost body pcrtion I 8. Similarly, the proper number or sections of compression sleeve extensions 51 can be coupled to one another between the coupling collar 56 and the coupling 58 which bears upon the abutment 59. Of course, the combined mandrel extension I6 used and compression sleeve extension 51 used should be of substantially equal lengths.

When the point is reached in the well casing B at which the tool A is to be set, the running-in string and tubular mandrel I0 are moved angularly to the right, to release the lock ring from the mandrel, as described in the above patent. The mandrel I0 is then moved upwardly,

the adjusting nut and guide 13, the lower packing structure 2 I, spacer sleeve 68, intermediate packing structure 20, compression sleeve extension 51, compression sleeve 54, upper packing structure I9, expander extension and expander 22 moving upwardly with the mandrel I0 with respect to the slips 24, which are prevented from moving upwardly by the frictional engagement of the drag springs 38 against the casing B. The

rubber packing sleeves

52, 65, 16 are suiciently hard as to transmit the upward movement without deformation. For that matter, as explained below, the uppermost packing sleeve 52 is softer than the intermediate packing sleeve 65, which, in turn, is softer than the lowermost packing sleeve 16, so that the uppermost packing sleeve 52 can be rst compressed, then the intermediate packing sleeve 65, then the lower packing sleeve 16, as upward movement of the mandrel I0 continues.

When the mandrel I0 is moved upwardly, the slip expander 22 is moved upwardly within the slips 24, urging the latter in a radial outward direction and into anchoring engagement with the wall of the casing B. When engaged with the casing, the slips 24 prevent the slip expander 22, expander extension 45 and the upper abutment 41 from moving any further. Accordingly, a continuation of the upward movement of the mandrel I0 urges all of the parts around the mandrel and below the upper abutment 41 in an upward direction, the upper compression sleeve 49 moving within the upper abutment 41, causing its flange 50 to foreshorten the uppermost packing sleeve 52, compressing it and expanding it laterally against the wall of the casing B. During such upward movement, the safety collar I2 is moved upwardly away from the upper abutment All (see Fig. 2a).

Since the upper packing sleeve 52 has been firmly compressed against the casing B, it prevents further upward movement of its compression sleeve 49 and the compression sleeve 54 and compression sleeve extension 51 secured to it. as well as the abutment 59 engaging the coupling 58 on the compression sleeve extension 51. Accordingly, continuation of the upward strain and movement of the mandrel l0 shifts the intermediate compression sleeve 6I within the abutment 59, causing its flange 66 to foreshorten the intermediate packing sleeve B5 and expand it outwardly against the casing B. During this upward movement, the threaded box I1 on the lowermost body portion I8 moves uwardly away from the abutment 59. When the intermediate sleeve has been firmly compressed against the casing, it prevents further upward movement of its compression sleeve 6I, the spacer sleeve 6@ and the lowermost compression sleeve 1l. Accordingly, as upward movement of the mandrel I0 continues, the adjusting nut 13 is moved upwardly along the lowermost compression sleeve 1 I, foreshortening the lowermost packing 16 and expanding it outwardly against the wall of the well casing B.

An adequate upward strain can be taken on the mandrel I0 to insure that the slips 24 have been embedded into the wall of the casing, and that all of the packing

sleeves

52, 65, 1li have been firmly expanded Iagainst the casing wall. The uppermost packing sleeve 52 is packed-off against an imperforate portion R, of the casing above the uppermost perforations P, whereas the lower two

rubber packing sleeves

65, 16 are packed-off on opposite sides of the lower perforations to form the localized zone S2 therein. y Fluid under pressure may now be pumped downwardly through the tubing string and through the mandrel passage 18 for outward passage through the mandrel ports Si and spacer sleeve ports 66 into the localized zon-e 82 between the lower packing structures 2i), 2l, this iiuid under pressure passing outwardly through the lowermost perforations P and into the formation. If a suiiiciently high pressure is imposed, the formation will be fractured.

This fracturing can be accomplished by pumping a suitable iluid, such as oil, into the formation. After the racturing has been accomplished, sand laden oil may be pumped into the formation, in order that the sand particles may serve as props in the fractured regions of the formation, holding the fractures or fissures open.

inasmuch as periorations P are present above the intermediate packing sleeve E35, the pressure can pass outwardly around the exterioi` oi the casing B, and then back into the casing through its perforations above the intermediate packing sleeve. Despite this occurrence, the uppermost packing 52 is still expanded outwardly against the casing portion R above the pei'iorations P, to prevent the annulus between the casing and the tubular running-in string from being sub- ,iectcd to pressures, which might be of such a high degree as to burst the casing. The pressure is localized at the perforated casing region, there being no bursting strains placed on the casing 9. at all, since the perforations P allow'thepressure internally and externally of the casing to be equalized.

After the necessary high pressures have been imposed on the formation and the high pressure fluid displaced into the formation through the lowermost set of perforations, theV running-in string and mandrel l may be lowered to enable the

packings

52, 65, 1B to retract and to force the slips 24 to retracted position. The lock ring 40 may be allowed to engage the ratchet teeth 44 on the mandrel I0, in order that the tubing string may be elevated the required distance until the two lower packing assemblies 20, 2| are disposed opposite the next higher group of perforations. The tool may again be anchored in packed-ofi condition, in the manner described above, to allow fluid under pressure to be forced through the next group of straddled perforations P. The tool may be released and elevated to the next higher position, where it can again be anchored in packedoff condition, this cycle of operations being continued until all of the perforations P have been straddled and the desired fluent mediums pumped through the perforations and into the formation. When the full operation has been completed, the parts of the tools may be shifted to retracted positions and the entire apparatus removed from the well bore.

When the tool is subjected to very high pressures, as, for' example, in excess of 8,000 p. s. i., such pressures tend to elongate the tubular mandrel I0. If it were not for the particular design of the tool disclosed, such elongation might tend to move the lower -adjusting nut and guide 13 in a downward direction, and if the compression sleeve 1| and its nange 10 and gauge ring 11 did not follow up movement of the adjusting nut and guide 13, and lowermost packing 1B might be released. Such release does not occur in the present tool, for reasons that now will be pointed out.

Inasmuch as the upward movement of the mandrel Il in setting the tool in packed-off condition has disposed the collar |2 and threaded box |,1 above the

several abutments

41, 59, the downward stretching of the tubing string and mandrel |0, under high pressure conditions, can take place, since adequate longitudinal clearance space is present between the collar and box members I2, |1 yand the

abutments

41, 59. Despite extensive stretching of the tubing string and mandrel I0, the safety collar I2 and box do not move suflioiently to engage the

abutments

41, 59, which action, if it could occur, might tend to shift the expander 22 downwardly and releasethe slips 24 from the casing.

As the mandrel l0 moves downwardly, as a result of the hydraulic stretching force, the lower adjusting nut and guide 13 moves downwardly with it. However, the lowermost packing 15 remains in packed-off condition, since the pressure is acting downwardly on the packing structure 2| over the annular area A between the periphery of the mandrel lll and the casing wall. The hydraulic pressure acting downwardly in this direction over the area A causes the abutment and compression sleeve 1| to follow up the downward movement of the lower adjusting nut 13 with a greater force than the eifective force moving the adjusting nut 13 in a downward direction away from the lowermost packing 16. This latter force is acting in an upward direction on the packing over the annular area B between the compression sleeve 1| and the wall of the well casing B. VThis annular area B is less than the annular area A by the annular area C of the compression sleeve itself. As a result, there is a differential area C with which the hydraulic pressure inthe localized zone 82 can act in a downward direction on the lower packing 16, holding it rmly compressed between the sleeve abutment 10 and the adjusting nut 13, and securely expanded outwardly against the well casing. rihe packing assembly 2| may move downwardly, if the mandrel lil moves or stretches downwardly, but Vit lwill still remain in packed-ofi condition under high operating conditions, to maintain the sealed localized Zone 82 between the packing assemblies 20, 2|.

The tool has been described inconnection with the progressive pressuring of an extended length of perforations P in a well casing B. For such use, the three packing assemblies I9, 2|), 2| are preferred, in order to locate the uppermost pack-.- ing assembly I9 above the perforations P and prevent the pressure from being imposed on the well casing itself. In the event that the tool is to be used in connection with a short perforated length of casing, which can be subtended by a pair of packing elements, the intermediate rubber packing t5 can be omitted, its place being taken by a rigid sleeve of the same length as the packing 65 when the latter is in retracted position. The tool would then be set in the well casing with the upper packing 52 disposed above the perforations P, and the lower packing 16 belowthe perforations, the tool being` anchored in packed-off condition through upward movement of the tubular mandrel I0, in essentially the same manner as before. l

The left-hand threaded connection I4 is provided between the safety collar |2, and the lower mandrel I3 to enable the slips Y24 to be substantially retracted, the event that Athey cannot otherwise be freed, as, for example, asa result of sticking or freezing of the lowervpacking portions against thewell casing.l fWhen, the well packer is set, the tubing string and the mandrel ||I have been rotated to theA right, in order to l. expand the lock ring 40 and allow the mandrel to be elevated as described above. Forcible retractionof the slips 24 can occur by coupling the mandrel I0 to the slips 24' through the lock ring 40. Suchcoupling action can take place as a result of returning the mandrel, |ll to its original position, as by rotating it to the left. Thislefthand rotation may produce a tendency to unscrew or loosen one or more of the right-hand threaded joints in the tubing string. To insure that this will not occur, instead of first rotating the tubing string and mandrel r|0 to the left, to allow contraction of the lock ring 40, and its coupling to the mandrel l0, thetubing string is first rotated to theright, lwhich'will unthread the left-hand safety joint I4. Thevtubingstring joints cannot unscrew, Vbecause the tubing string is being rotated to the rightwhile the left-hand threaded connectionat the safety joint is being broken. Aftery the safetyrcollar l2 has `been completely unscrewed from Vthe lower mandrel I3, substantially VYall resistance `to, rotation of the tubing string is removed. The latter may now be rotated to thel left, without danger of unthreading any of its right-hand joints, in order to recouple the mandrelA ||Ito the lock ring 40 and allowv the mandrel I0 to be elevated, suchelevation pulling the slips 24 upwardly along the expander 22 and inwardly out of engagement from thewell casing. When the slips 24 are released, the kpack-ings, even though ,they may notfberetracted, will slide 11 l along the casing wall. As `a result, the entire tool can be withdrawn from the well bore.

In the event that high pressures are encountered in the well casing B below the expanded lowermost packing 16, which high pressures might tend to release this packing, an equalizing valve structure may be provided in the lower portion of the lowermost body I8 (see Fig. 6). This equalizing valve includes a valve body threaded into the lowermost mandrel section I8, this body having side ports |0| communicating with a central body passage |02, and also having a lower socket |03 in which the lower end of a valve stem |04 is received. This valve stem extends upwardly through the passage |02 in spaced relation to its side wall and terminates in an upper head |05 engageable with a valve seat |06 in the body when `the head moves downwardly, to prevent downward now of uid through the mandrel passage 18. In view of the high pressures encountered, a metal-to-metal contact is provided between the head 05 and Valve seat |06, but, as assurance against leakage between the two, a supplemental seal ring |0`| may be clamped between the vupper part of the valve body and the mandrel |8, against which the head |05 also seats.

The valve head |05 and its stem |04 are urged in-a downward direction by a helical compression spring |018 bearing against the base of the socket |03 and also lagainst a washer |09, which rests upon a suitable nut ||0 threaded on the lower end of the valve stem |04. The compression spring |08 normally urges the valve head |05 downwardly to closed position. However, uid under sufficient `pressure may enter the valve body through the vports |0| and annular ypassage |02, acting upwardly on the head |05 to shift it from its seat |06 to open position.

During normal use of the tool, the valve head |05 remains closed against vits seat |06, since the pressure inside of the mandrel l0 is greater than the pressure outside of the tool below the .lowermost packing 16. In the event that the pressure below the lower-most packing tends to exceed 'the internal pressure, this excess pressure will elevate the head |05 from its -seat `|06 and allow the higher pressure fluid to venter the mandrel |10. This pressure may then leave the mand-rel through the mandrel and spacer sleeve por-ts '81, 69, 'and is effective for downward action over the lowermost compression sleeve 1| and pack-ing element 16, to lhold such packing 16 sealed `against the well casing B.

The inventors claim:

1. In a well packer: `a tubular body having `a port; a packing structure surroundingsaid body on each side of said port; means engageable with said packing structures to support said structures on opposite sides of said port; each of said packing structures including a sleeve slidable on said body and having a ange, a normally retracted packing on said sleeve having one end engaging said flange, an abutment slidable on said sleeve and engaging the other end of ysaid packing, and means for moving said'abutment and flange relatively toward each other to compress each packing and expand it laterally-outward.

2. In a well packer adapted to be lowered in a well casing: a tubular body having a port; first and second normally retracted casing engaging packings surrounding said bodyfand disposed on opposite sides of said port, said second ypacking having an upper end and a lower end; means engageable with the well ca-sing and with said first packing for resisting movement of said rst packing in the casing; abutment means on said body engageable with one of the ends of said second packing, a sleeve within said second packing and slidable on said body and within said abutment means, said sleeve having a flange engaging the other end of said second packing; and means between said packings for transmitting to said rst packing the force supplied by said body to said second packing, in order to compress both paekings and expand them against the well casing.

3. In a well packer adapted to be lowered in a Well casing: a tubular body having a port; upper and lower normally retracted packings surrounding said body and disposed on opposite sides of said port; means engageab'le with the well casing and with said upper packing for resisting movement of said upper packing in the casing; abutment means on said body engaging the lower end of said lower packing; a sleeve within said lower packing and slidableon said body and within said lower abutment means, said sleeve having a flange engaging the upper end of said lower packing; and means between said packings for transmitting to said upper packing the force supplied by said body to said lower packing, in order to compress both packings and expand them against the well casing.

4. vIn a well packer adapted to be lowered in a well casing: a tubular body having a port; upper and lower normally retracted packings surround- .ing said body and disposed on opposite sides of said port; an upper abutment movable relatively 4'of said body and engageable with the upper end of said upper packing; means engaging said abutment and the wall of the well casing to prevent upward movement of said abutment in the casing; a lower abutment mounted on said body and engaging the lower end of said lower packing; and spacer means on said body engaging the lower end of said upper packing and the upper vend of said lower packing, in order that upward movement of said body can effect compression of both packings and their outward expansion against the well casing.

5. In a well packer adapted to be lowered in a well casing: a tubular body having a port; upper, intermediate and lower normally retracted packings surrounding said body, said intermediate and lower packings being disposed on opposite sides of said port; means engagea-ble with the Well casing and with the upper end of said upper packing for resisting upward movement of said upper packing in the well casing; means on the body engaging the lower end of said lower packing; spacer means on the body between the lower end of said upper packing and the upper end of said intermediate packing; and spacer means on said body between the lower end of said intermediate packing and the upper end of said lower packing; both of said spacer means enabling upward movement of said body to eiect compression of said upper', intermediate and lower packings and their expansion against the well casing.

6. In a well packer adapted to be lowered in a well casing: a tubular body having a port; first and second normally retracted casing engaging packings surrounding said body and disposed on opposite sides of said port, each of said packings having an upper end and a lower end; a iirst sleeve slidable on said body and disposed within said rst packing; a second sleeve slidable on said body and disposed within said'second packing; a ange on said rst sleeve engaging one of the ends of said first packing; a flange on'saidsecond sleeve engaging one of the ends of said second packing; means engageable with said casing and the other end of said iirst packing, said first sleeve being slidable in said casing engageable means; means on said body engageable with the other end of said second packing, said second sleeve being slidable in said means on said body; and a spacer sleeve on said body located between and engageable with said rst and second sleeves.

7. In a well packer adapted to be lowered in a .well casing: a tubular body having a port; upper and lower normally retracted casing engaging packings surrounding said body and disposed on opposite sides of said port; an upper sleeve slidable on said body and disposed within said upper packings; a lower sleeve slidable on said body and disposed within said lower packing; a flange on said upper sleeve engaging the lower end of said upper packing; a flange on said lower sleeve engaging the upper end of said lower packing; means engageable with said casing and the upper end of said upper packing for resisting its upward movement in the casing, said upper sleeve being slidable in said casing engageable means; means on said body engageable with the lower end of said lower packing, said lower sleeve being slidablein said means on said body; and a spacer sleeve on said body located between and engageable with said upper and lower sleeves.l

8. In a well packer adapted to be lowered in a `well casing: a tubular body having a port; upper, intermediate and lower normally retracted casing engaging packings surrounding Said body, said intermediate and lower packings being disposed on opposite sides of said port; an upper sleeve slidable on said body and disposed within said upper packing; an intermediate sleeve slidable on said body and disposed within said intermediate packing; a lower sleeve slidable on said body and disposed within said lower packing; a flange on saidupper sleeve engaging the lower end of said upper packing; a flange on said intermediate sleeve engaging the lower end of said intermedatel packing; a ange on said lower sleeve engaging. the upper endA of said lower packing; means engageable with said casing and the upper end of said upper packing to resist its upward movement within the casing, said upper sleeve being slidable in said casing engageable means; means on said body engageable with the lower end of said lower packing, said lower sleeve being slidable in said means on said body; sleeve means on said body extending between and engageable with said upper sleeve and the upper end of said intermediate packing, said intermediate sleeve being slidable in said sleeve means; and a spacer sleeve on said body located between and engageable with said intermediate and lower sleeves.

I9. In a well packer adapted to be lowered in a well casing: a body; a sleeve slidable on the exterior of said body in close contacting leakproof relation with respect to said exterior of said body and having a flange; a normally retracted casingengaging packing on said sleeve, said packing having one end engaging said flange; and an abutment surrounding said body and slidable on said sleeve and engageable with the other end of said packing to expand said packing into engagement with the well casing.

l 10. In a well packer adapted to be lowered in a well casing: a tubular body having a port; a sleeve slidable on the exterior of said body in close contacting leakproof relation with respect tosaid yexterior of saidbody and having a flange to one side of said port, said sleeve having a skirt leading from said ange in a direction away from said port; a normally retracted casing-engaging packing on said skirt having an end engaging said ange; and an abutment surrounding said body and slidable on said skirt and engageable with the other end of said packing to expand said packing into engagement with the well casing.

11. In a well packer adapted to be lowered in a well casing: a tubular body having a port; a sleeve slidable on the exterior of said body below said port in close contacting leakproof relation with respect to said exterior of said body and having a ange, said sleeve having a skirt depending from said flange; a normally retracted casingengaging packing on said skirt having its upper end engaging said flange; and an abutment on said body slidable on said skirt and engageable with the lower end of said packing to expand said packing into engagement with the well casing.

12. In a well packer adapted to be lowered in a Well casing: a tubular body having a port; first and second normally retracted casing engaging packings surrounding said body and disposed on opposite sides of said port, said second packing having an upper end and a lower end; normally retracted slips disposed about said body; Y expander means engageable with said rst packing and coacting with said slips for expanding said slips against the casing to resist movement o f said first packing in the casing; abutment means on said body engageable with one of the ends of said second packing; a sleeve within said second packing and slidable on said body and within said abutment means, said sleeve having a ilange engageable With the other end of said second packing; and means on said body between said packings for transmitting to said rst packing the force supplied by said body to said second packing', in order to compress both packings and expand them against the well casing.

13. In a Well packer adapted to be lowered in a well casing: a tubular body having a port; upper and lower normally retracted packings surrounding said body and disposed on opposite sides of said port; normally retracted slips disposed around said body; expander means engageable with said upper packing and coacting with said slips for expanding them against the casing to resist upward movement of said upper packing in the casing means on said body engageable with the lower packing for urging said lower packing upwardly upon upward movement of said body in the casing and means on said body between said packings for transmitting to said upper packing the upwardly directed force supplied by said body to said lower packing, in order to compress both packings and expand them against the well casing.

14. In a Well packer adapted tobe lowered in a well casing: a tubular member having a port; upper and lower normally retracted packings surrounding said body and disposed on opposite sides of said port; an upper abutment movable relatively oi said body and engageable with the upper end of said upper packing; normally retracted slips disposed about said body; expander means engageable with said abutment and coacting with said slips for expanding them against the casing to resist upward movement of said upper abutment in the casing; a lower abutment mounted on said body and engaging the lower end of said lower packing; and spacer means on said body engaging the lower end of said upper packing and the upper end of said lower packing, in order that -said port;

accepte upward movement of said body can eiect compression of both packings and their outward expansion against the well casing.

15. In a well packer adapted to be lowered in a well casing: a tubular body having a port; upper, intermediate and lower normally retracted packings surrounding said body, said intermediate and lower packings being disposed on opposite sides of normally retracted slips disposed around said body; expander means engageable with the upper end of said upper packing and coacting with said slips for expanding them 'against said casing to resist upward movement of said upper packing in the casing; means on the body engaging the lower end of said lower packing; spacer means on the body between the lower vend of said upper packing and the upper end of said intermediate packing; and spacer means on said body between the lower end of said intermediate packing and the upper end of said lower packing; both of said spacer means enabling up- -ward movement of said body to eiiect compression of said upper, intermediate and lower pack- -ings and their expansion against the well casing.

16. In a well packer adapted to be lowered in a well casing: a tubular body having a port; upper and lower normally retracted casing engaging packings surrounding said body and disposed on opposite sides of said port; an upper sleeve slid- -able on said body and disposed within said upper packing; a lower sleeve slidable on said body and disposed within said lower packing; a flange on said upper sleeve engaging the lower end of said upper packing; a iiange on said lower sleeve engagingthe upper end of said lower packing; normally retracted slips disposed about said body; expander means engageable with the upper end 'of said upper packing and coacting with said `slips for expanding them against the casing to resist movement of said upper packing in the casing; means on said body engageable with the lower end of said lower packing; and a spacer sleeve on said body located between and engageable with said upper and lower sleeves.

17. In a well packer adapted to be lowered in a well casing: a tubular body having a port; upper, intermediate and lower normally retracted casing engaging packings surrounding said body, said intermediate and lower packings being disposed on opposite sides of said port; an upper sleeve slidable on said body and disposed within said upper packing; an intermediate sleeve slidable on said body and disposed within said intermediate packing; a lower sleeve slidable on said body and disposed within said lower packing; a iiange on said upper sleeve engaging the lower end of said `upper packing; a flange on said intermediate lsleeve engaging the lower end of said intermediate packing; a ilange on said lower sleeve engagvingV the upper end of said lower packing; normally retracted slips disposed about said body; expander means engageable with the upper end of said upper packing and coacting with said slips for expanding them against the casing to resist upward movement of said upper packing in the casing; means on said body engageable with the lower end of said lower packing; sleeve means on said body extending between and enagageable with said upper sleeve and the upper end of said intermediate packing; and a spacer sleeve on said body llocated between and engageable with said intermediate and lower'sleeves.

18. In a well packer adapted to be lowered in a 'well casing: a tubular body having a port, said body comprising an upper sectionanda lower I sectionjoined together by'a detachable left-hand threaded connection; upper and lower normally retracted casing engaging packings ,surrounding said body and disposed on opposite sides of said port; normally retracted slips disposed around said body; expander means engageable ywith said upper packing and coacting with said slips for expanding them against said casing to resist upward movement of said upper packing in said casing; means on said body engageable with the lower `packing/for urging said lower packing upwardly upon upward movement of said body in the casing; means on said body between said packings for transmitting to said upper packing the upwardly directed force supplied by said body to said lower packing, in order to compress both packings and expand them against the well casing; and releasable lock means between said upper section and slips for selectively coupling said slips for longitudinal movement with said .upper section or releasing said slips from said upper section to enable said body to move longitudinally with respect to said slips.

19. In a well` packer adapted to be lowered in a well casing:l a tubular body having a port; first and second normally retracted casing engaging packings surrounding said body and disposed on opposite sides of said port, each of said packings having an upper end anda lower end; rst abutment means engageable with the well casing and with one of the ends of said first packing for resisting movement of said iirst packing in the casing a first sleeve within said iirst packing and slidable on said body and within said rst abutment means, said rst sleeve Yhaving a flange engaging theother end of said rst packing;

econd abutment means on said body engageable with one of the ends of said second packing; a second sleeve within said second packing and slidable on said `bodyand within said second abutment, said second sleeve having a iiange engaging the other end of said second packing; and means between said sleeves for transmitting to said iirst packing the force applied by said body to said second packing, in rorder to compress both packings and expand them against the well casing.

20. In a well packeradapted to be lowered in a well casing: a tubular body having a port; rst and second normally retracted casing engaging packings surrounding said body and disposed on opposite sides of said port each of said packings having an upper end and a lower end; first abutment means engageable with the well casing and with one ofthe ends of said first packing for resisting movement of said rst packing in the casing; a first sleeve within said rst packing and slidable on said body and within said rst abutment means, said first sleeve having a flange engaging the other end of said iirst packing; second abutment means on said body engageable with one of the ends of said second packing; a second sleeve within said second packing and slidable on said body and within said second abutment, said second sleeve having a flange engaging the other end of said second packing; means between said sleeves for transmitting to said first packing the V:force applied by said body to said second packing,

in order to'cornpress both packings and expand them against the well casing; and sealing means 'between each sleeve vandsaid body to prevent huid leakageftherebetween.

` 21. f In a wellpacker adapted tc be lowered in a iwell casing: a'tubular body having a port; upper -and lower normally retracted casing engaging packings surrounding said body and disposed on opposite sides of said port; upper abutment means engageable with the well casing and with the upper end of said upper packing for resisting movement of said upper packing in the casing; an upper sleeve within said upper packing and slidable on said body and within said upper abutment means, said upper sleeve having a ange engaging the lower end of said upper packing; lower abutment means on said body and engaging the lower end of said lower packing; a lower sleeve within said lower packing and slidable on said body and within said lower abutment means; said lower sleeve having a flange engaging the upperend of said lower packing; and means between said sleeves for transmitting force therebetween.

22. In a well packer adapted to be lowered in a well casing: a body; a sleeve slidable on the exterior of said body and having a ange; a normally retracted casing-engaging packing on said sleeve, said packing having one end engaging said flange; an abutment surrounding said body and slidable on said sleeve and engageable with the other end of said packing to expand said packing into engagement with the well casing; and sealing means engaging said sleeve and the exterior of said body to prevent fluid leakage therebetween.

23. In a Well packer adapted to be lowered in a well casing: a tubular body having a port; a sleeve slidable on the exterior of said body below said port in close contacting leakproof relation with respect to said exterior of said body and having a flange, said sleeve havinga skirt depending from said ange; a normally retracted casing-engaging packing on said skirt having its upper end engaging said flange; and an abutment fixed to said body and slidable on said skirt, said abutment being engageable with the lower end of said packing to expand said packing into engagement with the well casing.

24. In a well packer adapted to be lowered in a well casing: a tubular body having a port; a sleeve slidable on the exterior of said body below said port and having a flange, said sleeve having a skirt depending from said 'ange; a normally retracted casing-engaging'packing on said skirt having its upper end engaging said flange; an abutment fixed to said body and slidable on said skirt, said abutment being engageable with the lower end of said packing to expand said packing into engagement with the well casing; and sealing means engaging said sleeve andl exterior of said body to prevent fluid leakage therebetween.

25. In a well packer adapted to be lowered in a well casing: a tubular member having a port; upper and lower normally retracted packings surrounding said body and disposed on opposite sides of said port; an upper abutment movable relatively of said body and engageable with the upper end of said upper packing; normally retracted slips disposed about said body; expander means engageable with said upper abutment and coacting with said slips for expanding them against the casing to resist upward movement of said upper abutment in the fcasing; an upper sleeve within said upper packing and slidable on said body and within said upper abutment, said sleeveihaving a flange engageable with the lower end of said upper packing; a lower abutment mounted on said body and engaging the lower end of said lower packing; a lowersleeve within said lower packing and slidable on said body and within said lower abutment, said lower sleeve having a ange engageable withthe upper end of said lower packing; and spacer means on said body disposed between and engaging said sleeves, in order that upward movement of said body can eiect compression of both packings and their outward expansion against the well casing.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,766,766 Shepard et al June 24, 1930 2,300,438 Spang Nov. 3, 1942 2,368,401 Baker Jan. 30, 1945 2,387,003 Barnes Oct. 16, 1945 2,423,653 Lauman July 8, 1947