US3548936A - Well tools and gripping members therefor - Google Patents

Description

United States Patent [72] Inventors Marion D. Kilgore Houston; Robert C. Pumpelly, Dallas, Tex. I21] Appl. No. 776,110 [22] Filed Nov. 15,1968 [45 Patented Dec.22, 1970 [73] Assignee Dresser-Industries, Inc.

Dnllns,'lex. a corporation of Delaware [54] WELL TOOLS AND GRIPPING MEMBERS THEREFOR 43 Claims, 31 Drawing Figs. [52] U.S. 166/216, 166/134, 166/139,166/217 [51] lntJ 1221b 23/00 [50] Field ofSearch 166/206, 209,118, 75, 85, 88,138,139,136, 137, 214,134, 216,217

. [56] References Cited UNITED STATES PATENTS 615,321 12/1898 Straubet al 166/214 2,076,314 4/1937 Zschokke... 166/134 3,161,424 12/1964 Maass 166/85 1 7 4 4/ 29 PFlWdzz-r /214 3,250,331 5/1966 Boyle 166/217 3,352,363 11/1967 Bennett 166/214 3,416,610 12/1968 Prescott, Jr 166/206 Primary Examiner-James A. Leppink Attomeys-Robert W. Mayer, Daniel Rubin, Peter J. Murphy,

Frank S. Troidl, Roy L. Van Winkle, Roderick W. Mac Donald and William E. Johnson, Jr.

ABSTRACT: A slip or gripping member that is used on well tools to lock the well tools at a desired location in a well bore.

The slip is movably mounted on the well tool and is provided with wall engaging teeth on relatively opposite sides thereof adjacent to each end. The wall engaging teeth are separated on the slip by a distance that is greater than the diameter of the well bore so that movement of the slip to an angular position brings the teeth into engagement with the well bore wall.

Relatively movable abutments are provided on the well too] w PATENTEUADECZZIHYB SHEET 01 0F INVENTOKS,

@KWMAM ATTOIQNEY 1 WELL rooLsANn GRIPPING MEMBERS THEREFOR BACKGROUND or THE-INVENTION Slips heretofore utilized on' oil well tools have had a toothed exterior and a. tapered interior. The tapered interior mates with an exterior taping surface o'n-a wedge or expander member that is forced underneath the slip to radially expand the slips forcing the toothed surface into 'holdingengagement with the well bore wall. Generally, the expander member is an annular frustoconical member'of unitary construction-while the slips are constructed from a plurality of segments. Some slips are constructed from a single annular ring of a material that fractures into segments when the wedge is forced thereunder.

Such slips havebeen generally satisfactory as an operational member in the well tools. However, the utilization of such slips does require the machining of both the wedge and the slips.

Thus, such slips are relatively expensive to manufacture.

Also, it is highly desirable to. maintain the well tools on which theslips are used to the shortest possible length. Slips having a double tapered interior surface operating with a pair of oppositely tapered expanders-canbe utilized to hold the tool against movement in the well bore in both directions. The overall length of the combination is considerably longer than desirable. Also, in the double holding-type slip, there is again presenteda relatively complex arrangement since the slips, two expanders, and means for retaining the segmented slips on the expanders must be'provided. i

As will be appreciated'by those skilled in the well tool art, the slip-expander combination will hold the well too] against movement in the well bore provided that the actuating mechanism which forces;, t he expander into engagement with the slip is not removed therefrom. If the force is released on the expander, the segmented slips can collapse inwardly and vide a slip that remains set until positively released.

As well tools utilizing the tapered-segmented slips are run.

into the well bore, the segmented slips are exposed to the action of the fluid in1the well bore and may be moved slightly outwardly where they can engage the well bore wall,'-the conduit wallor a discontinuityin the well bore or the conduit. When this occurs, the segmented slips are sometimes torn loose from the well tool resulting in the loss of the slips into the well bore and thus-preventing the proper operation of the well tool in the well bore when the desired location is reached. The loss of the slips into the well bore may necessitate an extremely expensive fishing job to remove the slips from the well The aforementioned problems are even more prevalent when the well tool is designed for use in very small bores or slim holes. In the small bore tools, the space available for the slips and expanders is greatly reduced. Thus, the slips must be constructed with less thickness and, 'correspondingly, the slips will be much more fragile. g

From'the foregoing, it will be apparent that the most desirable form of slip for use in a well tool is one that is positive in its holding engagement with the -well bore, will hold until positively released, can be mounted and actuated in the shortest possible length on the'well', tool, and is of the simplest and strongest construction possible.

. SUMMARY or rns INYENTION Arranged to engage the-wall of the well bore to hold the well too in the well bore. The slip comprises a body member havr in first and second ends, a wall engaging portion adjacent luof the ends, a distance between the wall engaging poring greater than the diameter of the well bore whereby W all engaging portions canengage the well bore wall and aportion intennediate the ends having a dimension less than the diameter of thewell bore, wherebythe well tool can move therethrough.

In another aspect,'this invention provides an improved well tool useful in a well bore, the tool comprising: an elongated body movable longitudinally through the well bore; a gripping member or slip carried by the body andhaving first and second ends, a first dimension smaller than diameter of the well bore, a second dimension larger than the diameter of the well bore, and wall engaging portions adjacent each end spaced by a distance including the second dimension; means for supporting the gripping member on the body for movement between a retracted position wherein the gripping member is out of engagement with the well bore wall and a holding position wherein the gripping member is in engagement with thewell bore wall; and, means for moving the gripping member between the holding and retracted positions.

One object of the invention is to' provide an improved slip structureof unitary construction.

The foregoing and additional objects and advantages of the invention will become more apparent as the following detailed description is read in conjunction with the accompanying drawings.

. BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a view, partly in cross section and partly in elevation, of a single-slip anchor shown in the unset condition in the well bore.

FIG. 2 is a view similar to FIG. 1 but illustrating the anchor in the set condition inthe well bore.

FIG. 3 is 'a horizontal cross section taken generally along the line 3-3 of FIG. 1.

FIG. 4 is an enlarged elevation view of a slip constructed in accordance with the invention.

FIG. 5 is a cross section of the slip of FIG. 4 taken along the line 5 5 of FIG. 4. 1

FIG. 6 is a top end view of the slip of FIG. 4.

FIG. 7 is an auxiliary bottom end view of the slip of FIG. 4.

FIGS. 8A and 8B, taken together, form a view partly in cross section and partly in elevation; of a mechanicallyactuated packer in the unset condition. I

FIG. 9 is a layout of a .I-slot utilized in the packer illustrated in FIGS. 8A and 8B.

FIGS. 10A and 10B, taken togethenform a view similar to FIGS. 8A and 8B, but illustrating the packer in the set condition.

FIG. 11 is a view, partly in elevation and partly in cross section, of a portion of the packer shown in FIG. 8A and 8B in a different stage of operation.

FIGS. 12A and 12B, taken together, form a view, partially in cross section and partially in elevation, of a two-slip anchor in the unset condition.

FIG. 13 is a view, partly in cross section and partly in elevation, of a portion of the anchor of FIGS. 12A and 128 in another operating position.

FIG. 14 is a horizontal cross section taken along the line l4-l4 of FIG. 13.

FIGS. 15A, 15B and 15C, taken together, form a view. partly in elevation and partly in cross section, of a hydraulically-actuated packer in the unset condition.

FIGS. 16A, 16B and 16C, taken together, form a view similar to FIGS. 15A, 15B and 15C but showing the packer in the set condition.

FIGS. 17A and 17B, taken together, form a view, partly in elevation and partly in cross section, of a bridge plug arranged DESCRIPTIONOF THE EMBODIMENT OF FIGURE I Referring to the drawings and to FIG. 1 in particular, shown therein and generally designated by the reference character 30 is a single slip, anchor assembly that is positioned in a casing 32 located in a well bore 34. While the anchor assembly 30 will most frequently be used within a conduit, such as the casing 32, it should be understood that the anchor assembly-30 may also be utilized within a well bore having no conduit disposed therein.

The anchor assembly 30 includes an elongated body or mandrel 36 that extends therethrough. The mandrel 36 is arranged at its upper end for connection with 'a tubing string 38 that extends into well bore 34 from the surface of the well.

The lower end of the elongated member 36 is also arranged to be connected with other well apparatus. As illustrated in FIG. 1, the lower end of the mandrel 36is connected with a tubular member 40. Intermediate its ends, the mandrel 36 is provided with a relatively short length of male thread 42. The male thread 42 mates with a longer femalethr ead- 44 that is formed in the interior of an upperhead member 46.

A plurality of how springs 48, or other suitable means for frictionally engaging the interior wall. of the casing 32, are provided on the exterior of the upper head 46. The frictional engagement between the bow springs 48 and the interior wall of the casing 32 permits relative rotation between the mandrel 36 and the upper head 46. The lower end of the upper head 46 has a downwardly facing shoulder or abutment 50 that is arranged to engage a gripping member or slip 52 for reasons that will become more apparent'as the'description proceeds. An annular recess 51 in the upper head 46 provides a downwardly facing shoulder 53 and an'upwardly facing shoulder 54 near the lower end thereof.

The shoulder 54 is illustrated as being in engagement with an annular abutment 56 that is carried by the upper end of a slip sleeve 58. The slip sleeve 58 slidingly encircles the mandrel 36 and extends downwardly through the slip 52.

At its lower end, the slip sleeve 58 has an annular abutment 60 arranged to engage a downwardly facing shoulder 62 formed in a lower head 64. A pair of diametrically opposed slots 66 (both slots 66'are shown in FIG. 3) are provided in the slip sleeve 58 to receive pivot lugs or pins 68 that are mounted in the slip 52. The slot and pin arrangement permits both sliding and pivotal movement of the slip 52 relative to the slip sleeve 58.'An extemallug 70 onthe slip sleeve 58 engages a downwardly facing shoulder 72 on the slip 52 to prevent pivoting of the slip 52 while the assembly3 0. is being run into the well bore 34 and to=return the slip 52 to the position illustrated in FIG. 1 when retrieving the assembly from the well bore 34.

The slip 52 is a unitary member having a bore 74 extending therethrough that intersects generally parallel end surfaces 76 and 78. The slip 52 is re-bored or relieved providing enlargements 80 and 82 so that the slip 52 can be pivoted on the slip sleeve 58. A toothed, wall engaging portion 84 is located on the exterior of the slip 52 adjacent the end surface 76 and a toothed, wall'engaging portion 86 is located on the exterior of the slip 52 adjacent the end surface 78. The teeth illustrated on the portions 84 and 86 are arranged when in engagement with the casing 32, to hold the assembly 30 against both upwardly and downwardly directed forces. A leaf spring 88 is secured to the slip 52 and has one end engaging the slip sleeve 58 to bias the slip 52 toward the position illustrated in FIG. 1, that is, toward a retracted position.

The-lower head 64 includes an upwardly facing shoulder or abutment 90 that is engageable with the end surface 78 of the slip "52 for reasons which {will .be discussed more fully hereinafter. A shear screw 92 is mounted in the lower head 64 and extends into holding eng'a g'ement with the body 36. The shear screw 92 retains the lower head 64 in the position illustrated on the body 36 until patted; I I

OPERATION OF THE EMBODIMENT OF FIG. 1

The anchor assembly 30 is assembled as illustrated with the tubing string 38 and lowered therewith into the well bore 34. The mating male thread 42 and female thread 44 on the upper head46j are engaged in the position illustrated in FIG. I. Also as illustrated in FIG 1, the slip sleeve 58 is suspended between the upwardly facing shoulder 54 on the upper head 46 in the downwardly'fa'cing shoulder 62 on the lower head 64. With the sleeve 58 thus positioned, thelug 70 thereon is in engagement with the shoulder 72 on the slip 52. Engagement between the shoulder 72 and the lug 70, will retain the slip 52 in the retracted positionshown. Should the slip 52 move up wardly' on the slip sleeve 58, the leaf spring 88 will prevent pivoting of the slip 52 into the holding position. The slots 66 prevent engagement between the slip 52 and shoulder 50 even if the slip 52' does move upwardly.

Upon reaching the desired location in the well bore 34,

right-hand rotation isimparted to the tubing string 38. The bow springs 48, which are in frictional engagement with the interior wall' of the casing 32, prevent rotation of the upper head 46 so that relative rotation occurs between the male and female threads 42 and 44, respectively. Due to the relative rotation, linear motion, in a downward direction, is imparted to theupper head 46, moving the shoulder 50 toward the end surface 76 of the slip 52i- The downward movement of the upper head 46 is relative to the slip sleeve 58 alsountil the abutment 56 on the slip sleeve engages the downwardly facing shoulder 53 in the upper head 46. Upon such engagement, the slip sleeve 58 is carried downwardly, moving the lugs 70 relatively downwardly with respect to the slip 52 .to the position illustrated in FIG. 2. When thelug 70 moves away from the shoulder 72, the slip 52 is in a position to be pivoted relative to the slip sleeve 58.

Continued downward movement of the upper head 46 as a result of the'relative rotation, brings the end surface 78 on the slip 52 into engagement with the upwardly facing shoulder or abutment 90 on the lower head 64 and also brings the downwardly facing shoulder or abutment 50 on the upper head 46 into engagement with the surface 76 on the slip 52. The engagement between either or both of the surfaces 76 and 78 with therespective abutment 50 and abutment 90pivots the slip 52 about the pins68 into the position illustrated in FIG. 2.

Asshown therein, the slip 52 is pivoted into the holding position, that is into the position wherein the toothed, wall engaging portions 84' and 86. are in holding engagement with the interior wall of the casing 32. Since the lateral distance between the surfaces 84 and 86 is greater than the interior diameterof the casing 32, the slip 52 is securely locked to the casing 32 and, even though either or both of the abutments 50 or 90 may be moved away fromthe slip, the slip 52 will remain set as shown.

Disengagement of the slip 52 and retrieval of the anchor as-" sembl'y'30 is accomplished by imparting a relatively opposite. rotation to the tubing string 38 whereby the upper head 46' moves upwardly relative to the mandrel 36 and slip sleeve 58.

When the abutment 56 again engages the upwardly facing surface 54 in the upper head 46, the slip sleeve 58 will be pulled upwardly therewith.

Continued upward movement of the upper head 46 and the v created that will disengage the portions 84 and 86 from the interior wall of the casing 32. Once the disengagement between the portions 84 and 86 with the casing 32 has been initiated, the spring 88 will bias the slip 52 into the retracted position.

In the event that rotation cannot be imparted into the tubing string 38, relative rotation between the body 36 and upper head 46 cannot be attained, or the slip 52 cannot be released by rotation, the anchor assembly 30 can be retrieved by exerting an upward pull on the tubing string 38 sufficient to shear the screw 92 carried in the lower head 64.-When this occurs, the upward force on the tubing string 38 is transmitted through the body 36 and through the mating threads 42 and 44 into the upper head 46. The upward force can then raise the upper head 46 relative to the set slips 52.

As the upward movement of the upper head 46 continues, the abutment 56 on the slip sleeve 53 engages the upwardly facing surface 54 on the upper head 46, pulling the lug 70 into engagement with the shoulder 72 in the slip 52 and returning the slip 52 to the retracted position. The lower head 64 is retrieved due to the engagement of the abutment 60 on the lower end of the slip sleeve 58 with the downwardly facing surface 62 in the lower head 64.

DESCRIPTION OF THE SLIP OF FIG. 4

FIGS. 4, 5, 6 and 7 illustrate another form of a slip constructed in accordance with the invention and generally designated by the reference character 100. The slip 100 could be utilized on the anchor assembly 30 in lieu of the slip 52. As shown therein, the slip 100 comprises a unitary body 102, having an opening 104 extending therethrough.

As is shown most clearly in FIG. 5, the opening 104 is formed by a first cylindrical bore 106 that extends along an axis 108. To permit the slip 100 to pivot on a well tool (not shown), and as previously described in connection with the slip 52 of FIG. 1, a second bore 110 extends through the body 102 along an axis 112 that is disposed atan angle relative to the axis 108. The intersecting bores 106 and 1110 provide enlargements in the opening 104 whereby the slip 100 can pivot when mounted on a well tool.

The body 102 includes an upper end 114 and a lower end 116fThe upper and lower ends 114 and 116, respectively, are intersected by both bores 106 and 110. It will be noted that ends 114 and 116 are disposed substantially perpendicularly with respect to the axis 108 of the bore 106. Thus, the end 114 is generally parallel to the end 116.

The body 102 is provided with an arcuate wall engaging portion 120 located adjacent the end 114 and an arcuate wall engaging portion 122 located adjacent the end 116. The wall engaging portion 120 is provided'with downwardly oriented teeth 124 while the wall engaging portion 122 is provided with upwardly oriented teeth 12 6. Thus, when the slip 100 is in engagement with a well casing (not shown) or the wall of a well bore (not shown) the teeth 126 will aid in preventing movement of the slip upwardly therein and the teeth 124 will aid in preventing movement downwardly therein.

The body 102 is constructed so that the dimension 128 between the wall engaging portion 120 and 122 as measured along a line that is generally perpendicular to the surfaces will be greater than the diameter of the conduit (not shown) or well bore (not shown) in which the slip is run. That is, if the slip 100 is mounted on a well tool with the axis 108 aligned with the longitudinal axis of the tool, the distance 123 will be greater than the diameter of the conduit or well bore in which the tool is run. When the slip 100 is in engagement with the conduit. it is in the holding position.

The body 102 is also constructed to include a dimension 130 that is measured substantially perpendicular to the axis 112 and will be less than the interior diameter of the conduit or well bore in which the slip 100 is run to permit movement of the slip therethrough. Stated in another way, when the axis 112 is aligned with the longitudinal axis of the well tool (not shown) on which the slip 100 is mounted, the wall engaging portion and 122 will not engage the conduit or well bore wall since the dimension is less than the internal diameter thereof. When the slip 100 is not in engagement with the conduit, it is in the retracted position.

Threaded holes 132 and 1341, which are located in axial alignment, extend through the wall of the body 102 in a direction substantially perpendicular to the axes 100 and 112. The holes 132 and 134 are each arranged to receive a threaded pin (not shown) that will engage the well tool on which the slip 100 is mounted to permit pivotal movement of the slip 100 between the holding and retracted positions. Thus, the center line of the holes 132 and 134i define a pivot axis for the slip 100.

Intermediate the ends 114 and 116 there is provided on the body 102 a downwardly facing shoulder 138. The shoulder 138 is offset from the pivot axis 136 of the slip 100 in a direction so that engagement of the shoulder 138 with a portion of the well tool (not shown) pivots the slip 100 into the retracted position wherein the axis 112 of the slip 100 is aligned with the longitudinal axis of the tool.

In a substantially diametrically opposed position on the body 102 relative to the shoulder 138, a recess 140 is formed in the body 102 to receive one end of a leaf spring, such as the leaf spring 88 illustrated in FIG. 1. The threaded opening M2, extending from the recess 140 into the opening 104, is provided to receive a threaded fastener (not shown) for attachment of the leaf spring (not shown) to the body 102.

DESCRIPTION OF THE EMBODIMENT OF FIGURES 8A AND 83 FIGS. 8A and 8B, taken together, illustrate a mechanicallyactuated packer assembly generally designated by the reference character 200. Extending through the packer assembly 200 is a hollow body or mandrel 202.

The mandrel 202 includes a thread 204 at the upper end that is adapted to be connected with a tubing string (not shown) for extending the packer assembly 200 into the conduit 201 (see FIG. 10A). At its lower .end, the mandrel 202 screw provided with a thread 206 that is arranged for connecting the packer assembly 200 with apparatus in the well therebelow.

Near the lower end of the mandrel 202 and on the exterior thereof there is formed a J-slot 208. The J-slot 208 can be seen more clearly in the layout view of FIG. 9. The .I-slot 203 is constructed to receive a shear screw or pin 210 that is carried by a drag block assembly 212.

As shown in FIG. 8B, the drag block assembly 212 includes a drag block body 214 that slidably encircles the lower portion of the mandrel 202. Disposed within recesses in the drag block body 214 are a plurality of drag blocks 216 that are urged outwardly by a plurality of springs 218. The drag blocks 216 are provided to frictionally engage the interior wall of the well bore or conduit 201 in which the packer assembly 200 is run.

At its upper end, the drag block body 214 includes an annular recess 220, providing an upwardly facing shoulder 222 and a downwardly facing shoulder 224. An upwardly facing abutment 226 on the upper end of the drag block body 214 above the annular recess 220 is arranged to engage a lower slip 228.

The lower slip 228 has a bore 230 extending therethrough that is constructed as was the bore 104 of the slip 100 (see FIG. 5). The bore 230 extends through the slip 220 intersecting a lower end 232 and an upper end 230. As clearly shown in FIG. 8B, the lower end 232 and upper end 234 he in planes disposed at an angle relative to each other. The lower end 232 includes portions 235 that are offset from the longitudinal axis of the packer assembly 200 for reasons that will become apparent hereinafter.

On its exterior, the slip 228 is provided with a lower gripping surface 236 disposed adjacent the lower end 232 and upper gripping surface 238 disposed adjacent the upper end 234. The surfaces 236 and 238 each have downwardly oriented teeth formed thereon.

A leaf spring 240 is attached to the exterior of the slip 228 and functions to bias the slip 228 toward the retracted position as illustrated in F 1G. 88. Also, as described in connection with the slip 100, the slip 228 includes a pair of pivot pins 242 forming a pivot axis for the slip 228 that is disposed substantially perpendicular to the longitudinal axis of the packer assembly 200. The pivot pins 242 are received in slots 244 shown by a dash line in FIG. 1. The slots 244 are formed in a lower slip sleeve 246.

The lower slip sleeve 246 extends through the slip 228 and has an annular abutment 248 on its lower end that is engageable with the downwardly facing shoulder 226 in the upper end of the drag block body 214. The lower end of the lower slip sleeve 246 is also in engagement with a corrugated annular spring 250.

The corrugated spring 250 also engages the upwardly facing shoulder 222 in the drag block body 214 biasing the slip sleeve 246 upwardly. Since he slip 228 is connected to the slip sleeve 246 by pivot pins 242, the slip 228 is also biased upwardly. Thus, the lower end 232 of the slip 228 is held out of engagement with the annular abutment 226 on the upper end of the drag block body 214. With the end 232 out of engagement with the abutment 226, the slip 228 can pivot much more readily toward the holding position as shown in FIG. 108.

An annular flange 252 encircles the upper end of the lower slip sleeve 246. The flange 252 is engageable with an interior flange 254 carried by a packer compression sleeve 256 that slidingly encircles a packing shell 253. Both the sleeve 256 and shell 258 are slidable on the mandrel 202.

A plurality of deformable packing elements 260 encircle the packing shell 258. While a plurality of elements 260 are illustrated, it will be understood that a single packing element or other suitable arrangement can be used if desired. The lower end of the lowermost packing element 260 is in engagement with the upper end of the compression sleeve 256.

As clearly shown in F108. 8A and 8B, the packing shell 258 is spaced radially from the mandrel 202 thereby forming a passageway 261 that extends upwardly through the packer assembly 200. A plurality of ports 262 are formed in the compression sleeve 256 below the packing elements 260 and a plurality of ports 264 are formed in the packing shell 258 above the packing elements 260. Thus, a bypass passageway that includes the ports 262 the passageway 260 and the ports 264 is formed in the packer assembly 200.

The packing shell 258 has a shoulder 266 engaging the upper end of the uppermost packing element 260 whereby telescoping movement between the compression sleeve 256 and the packing shell 258 deforms the packing elements 260 relatively outwardly into sealing engagement with the interior wall of the conduit 201 (see FIG. 10A).

The packing shell 258 also includes an interior shoulder 268 that is arranged to engage a valve retainer 270 carried by the mandrel 202. When the retainer 270 engages the shoulder 268, telescoping of the sleeve 256 and shell 258 can be accomplished to deform the packing elements 260. An interior flange 272 on the packing shell 258 is arranged to engage an annular flange 274 on the mandrel 202 to limit the upward travel of the mandrel 202 relative to the shell 258.

Disposed between the flange 274 on the mandrel 202 and the valve retainer 270 is a resilient valve element 276. The resilient valve element 276 is sized to enter the interior of the packing shell 258 and form a seal therewith to close the passageway 261 and, thus, to close the bypass passageway in the assembly 200.

An upwardly facing shoulder or abutment 278 formed on the upper end of the packing shell 258 is arranged to engage an upper slip 280. The upper slip 280 is constructed substantially identically to the lower slip 228. The slip 280 is inverted, relative to the lower slip 228, on the packer assembly 200.1t will be noted however, that only one leaf spring 240 is provided on the slip 280 instead oftwo as shown on the lower slip 228.

The upper slip 280 has a lower end 282 arranged to engage the abutment 278 on the packing shell 258 and has a toothed, gripping surface 283 adjacent to the end 282. An upper end 284 on the upper slip 280 is disposed in a plane located at an angle relative to the lower end 282. A toothed, gripping surface 285 is provided adjacent the end 284. The teeth on the surfaces 283 and 285 are oriented in an upward direction. Surfaces 287, which are located on the upper end 284 of the slip 280, are offset from the longitudinal axis of the packer assembly 200 for reasons that will become apparent hereinafter.

The upper slip 280 has a downwardly facing shoulder 286 thereon located intermediate the upper and lower ends 282 and 284. The shoulder 286 is positioned, relative to pivot pins 288 carried by the upper slip 280, so that engagement between the shoulder 286 and a lug 290 that is located on an upper slip sleeve 292 will result in rotation of the upper slip 280 into the retracted position shown in FIG. 8A.

The upper slip sleeve 292 includes a pair of slots 294 shown by a dash line that are arranged to receive the pivot pins 288. The upper end of the upper slip sleeve 292 includes an annular flange 2% that is engageable with a spring housing 298 carried by the mandrel 202.

A coil spring 300 disposed within the spring housing 298 has one end in engagement with the mandrel 202 and the opposite end in engagement with the flange 296 on the upper slip sleeve 292. The spring housing 298 has a lower end 302 that is engageable with the upper end 284 of the slip 280 for purposes that will be described more fully hereinafter.

OPERATION OF THE EMBODlMENT OF FIGURES 8A AND 88 FIGS. 8A and 8B illustrate the position of the various components of the packer assembly 200 as the packer assembly is being lowered into the conduit 201.

As shown in FlGS. 8B and 9, the pin 210 is disposed in the upper end of the lower portion of the .l-slot 208. With the pin 210 in this position, the drag block assembly 212 cannot move upwardly relative to the mandrel 202 even though the drag blocks 216 are in frictional engagement with the interior wall of the conduit 201.

With the drag block assembly 212 retained on the mandrel 202, the downwardly facing shoulder 224 in the drag block assembly 212 engages the abutment 248 on the lower end of the lower slip sleeve 246, pulling the lower slip sleeve 246 downwardly therewith. The annular flange 252 on the upper end of the lower slip sleeve 246 is in engagement with the interior flange 254 on the packer compression sleeve 256, pulling the packer compression sleeve 256 therewith into the conduit 201. The upper end of the compression sleeve 256 and the lower end of the packing shell 258 are in engagement as shown in FIG. 8B and, thus, the packing shell 258 and the packing elements 260 are also pulled into the conduit 201.

The lower slip 228 is retained in the retracted position illustrated under the urging of the leaf springs 240. Therefore, even though the lower slip 228 may ride upwardly in the slots 244, the lower slip 228 cannot move into holding position and, thus, cannot engage the interior wall of the conduit 201 during the running of the packer assembly 200 into the well bore.

It should also be noted that as the packer assembly 200 is lowered into the well bore, the bypass valve element 276 is in its upper position, that is, it is in a position wherein the passageway 261 is open to permit fluid to bypass the packing elements 260 by flowing from the ports 262 through the passageway 261 and outwardly through the ports 264.

At the upper end of the packer assembly 200, the coil spring 300 urges the upper slip sleeve 292 relatively downwardly holding the annular flange 296 thereon in engagement with the lower end of the spring housing 298 and, thus, holding the upper slip 280 in a position out of engagement with the lower end 302 of the spring housing 200. The lug 290 on the upper slip sleeve 292 engages the downwardly facing shoulder 286 on the upper slip 280 to prevent engagement between the lower end 282 of the upper slip 280 and the upwardly facing shoulder 278 on the packing shell 258. Should the upper slip 280 ride upwardly due to fluid resistance, the leaf spring 240 retains the upper slip 280 in the retracted position as illustrated in FIG. 8A. Thus, the upper slip 280 cannot engage the wall of the well bore as the packer assembly 200 is lowered therein.

Upon reaching the desired location in the well bore for setting the packer assembly 200, the mandrel 202 is raised slightly by pulling upwardly on the tubing string (not shown). The upward movement of the mandrel 202 places the shear pin 210 in the position 210a as shown in FIG. 9, since the drag block assembly 212 is retained in a stationary position by the frictional engagement of the drag blocks 216 with the interior wall of the conduit 201.

The mandrel 202 is then rotated in the appropriate direction and simultaneously lowered to move the pin 210 from the position 210a to the position 21%. As the mandrel 202 moves downwardly, the bypass valve element 276 moves into the passageway 261 forming a seal with the packing shell 258, closing the passageway 261. When the valve retainer 270 engages the interior shoulder 268 in the packing shell 258, downward movement is also imparted to the packing shell 258.

Continued downward movement of the mandrel 202 and the packing shell 258 forces the packer compression sleeve 256 downwardly relative to the lower slip sleeve 246 and lower slip 228. The sleeve 246 and lower slip 228 are retained in a relatively fixed position by the drag block assembly 212. The downward movement of the packer compression sleeve 256 continues until the flange 254 thereon engages the upper end 234 of the lower slip 228 as illustrated in FIG. 103. The engagement between the flange 254 and the upper end 234 pivots the lower slip 228 into the holding position wherein the gripping surfaces 236 and 238 on the lower slip 228 are in firm engagement with the interior wall of the conduit 20]. When this occurs, further downward movement of the packer compression sleeve 256 is prohibited.

Continued downward movement of the mandrel 202 carries the packing shell 258 downwardly therewith in telescoping relationship to the packer compression sleeve 256. As the telescoping movement between the packer compression sleeve 256 and the packing shell 258 occurs, the packing elements 260 are deformed outwardly into sealing engagement with the conduit 201 as illustrated in FIG. 10A.

Simultaneously with the foregoing, the mandrel 202 through the coil spring 300 has moved the upper slip sleeve 292 downwardly so that the lug 290 is out of engagement with the shoulder 286 on the upper slip 280. Also, the relative downward movement of the upper slip sleeve 292 relative to the upper slip 280 has moved the slots 294 to a position wherein the upper end thereof engages the pivot pins 288 to carry the upper slip 280 downwardly forcing the lower end 282 into engagement with the abutment 278 on the packing shell 258.

The engagement between the lower end 282 of the upper slip 280 and the abutment 278 pivots the upper slip 280 into the holding position illustrated in FIG. 10A. As shown therein. the grippingsurfaces 283 and 285 are in firm holding engagement with the conduit 201. As described, the packer assembly 200 is in the set position with the upper and lower slips 280 and 228, respectively, in holding engagement with the conduit 201 and with the packing elements 260 deformed into and retained in sealing engagement with the conduit 201 During the operation of setting the packer assembly 200 by compression, that is, by setting weight thereon as previously described, the upper slips 280 are moved into holding engagement with the conduit 201 during deformation of the packing elements 260. To assure that the desired deformation of the packing elements 260 is attained, the upper slip 280 is provided with the surfaces 287. As may be seen in FIG. 10A, the surfaces 287 on the upper slip 280 are displaced to the right of the longitudinal axis of the packer assembly 200 and. of

course, to the right of the pivot axis formed by the pivot pins 288. Thus, the lower end 302 of the spring housing 298 will engage the surfaces 287 if sufficient weight is exerted to compress the coil spring 300.

When such engagement occurs, a moment is created tending to rotate the upper slip 280 toward the retracted position. Therefore, it can be appreciated that application of additional weight to provide more deformation of the packing elements 260 will rotate the upper slip 280 toward the position illustrated in FIG. 11 due to the engagement between the surfaces 287 and the lower end 302 of the spring housing 298. In the position shown, the upper slip 280 can slide downwardly within the conduit 201, permitting the direct application of the weight through the mandrel 202 and the packing shell 258 to the packing elements 260.

Sometimes, the packer assembly 200 will be utilized in wells wherein sufficient tubing weight is not available to set the packer assembly 200 by applying weight thereto, that is, insufficient weight is available to set the packer assembly 200 in compression. When such a condition is encountered, the packer assembly 200 is first set in compression, as previously described attaining a holding engagement between the upper and lower slips 280 and 228 and the conduit 201. After this point in the setting of the packer assembly 200 has bee attained, the mandrel 202 is raised, moving the pin 210 into the position 210c as shown in FIG. 9.

As the mandrel 202 is raised, the compressive force exerted on the coil spring 300 is reduced. However, the energy stored therein, retains the upper slip sleeve 292 in the position illustrated in FIG. 10A with the lug 290 thereon spaced from the downwardly facing shoulder 286 on the upper slip 280.

The upward force, transmitted from the mandrel 202 into the pin 210, carries the drag block assembly 212 upwardly and the abutment 226 on the upper end of the drag block assembly 212 engages the surfaces 235 on the lower end 232 of the lower slip 228. The engagement between the abutment 226 and the surfaces 235 results in a moment being exerted on the lower slip 228 tending to rotate the lower slip 228 toward the retracted position as previously described in connection with the downward movement of the upper slip 280 and as shown in FIG. 11.

As a result of the movement of the lower slip 228 toward the retracted position, the lower slip 228 is disengaged from the conduit 201 and can move upwardly with the mandrel 202 and drag block assembly 212. As clearly shown in FIG. 1013, the upper end 234 of the lower slip 228 is in engagement with the flange 254 of the packer compression sleeve 256, forcing the packer compression sleeve 256 upwardly relative to the packing shell 258.

The abutment 278 on the upper end of the packing shell 258 is in engagement with the lower end 282 of the upper slip 280 and, thus, is prevented from moving upwardly. As a result, a telescoping movement occurs between the packer compression sleeve 256 and the packing shell 258 and the packing elements 260 are deformed into sealing engagement with the conduit 201.

When the upward force is relieved on the mandrel 202, the lower slip 228, through its engagement between the upper end 234 and the flange 254 on the lower end of the packer compression sleeve 256, returns to the holding position, that is, into holding engagement with the conduit 201. Thus, the upper slip 280 and the lower slip 228 are in firm holding engagement with the conduit 201, retaining the packing elements 260 deformed into sealing engagement with the conduit 201.

When it is desired to retrieve the packer assembly 200 from the well bore, the tubing string (not shown) and the attached mandrel 202 are rotated in the relatively opposite direction and raised so that the pin 210 returns to the position 2100 as shown in FIG. 9. As the mandrel 202 moves upwardly, the annular flange 274 thereon engages the interior flange 272 on the packing shell 258. The engagement between the annular flange 274 and. interior flange 272 raises the packing shell 258 to relieve the compressive load on the packing elements 260.

As upward movement continues, the lower end of the packing shell 258 engages the upper end of the packer compression sleeve 256, raising the flange 254 out of engagement with the upper end 234 of the lower slip 228. When this occurs, the leaf springs 240 pivot the lower slip 228 into the retracted position as illustrated in FIG. 88.

If the lower slip 228 is wedged into holding engagement with the conduit 201 so thatthe leaf springs 240 cannot return the lower slip 228 to the retracted position, the upwardly facing abutment 226 on the drag block assembly 212 comes into engagement with the Surfaces 235cm the lower slip 228 applying a moment thereto and aiding the leafsprings 240 in returning the lower slip 228' to thesett'acted position. The bypass valve element 276 has been pulled-out of the passageway 261, equalizing the pressures above and below thepacking elements 260 prior to releasing the slips 228 and 280.

Simultaneously with the foregoing, the annular flange 296 on the upper end of the upper slip sleeve 292 engages the lower end 302 of the spring housing 298. When this occurs, theupper slip sleeve 292 is pulled upwardly relative to the upper slip 280 bringing the lug 290 on the upper slip sleeve 292 into engagement with the downwardly facing shoulder 286, on the upper slip- 280.'When the lug 290 engages the downwardly facing shoulder 286, a moment is applied to the upper slip 280 pivoting the upper slip 280 into the retracted position as illustrated in FIG, 8A. Upon reachingthis position, the various components of the'pac'ker assembly 200 are in the retrieving position with the packing elements 260 returned substantially to the position illustrated in FIG. 8A and with the upper and lower slips 280 and 228' in the retracted positions shown in FIGS. 8A and 8B. 1 v

If, for some reason, the packer'assembly '200becomes stuck and cannot be retrieved in the; normal fashion, an upward force of sufficient magnitude exe'rted'on the mandrel 202 shears the pin 210 permitting themandrel 202 to move upwardly relative to the drag block assembly 212. After shearing the pin 210, the packer can bereturned to the retrieving position as previously described. i

EMBODIMENT OF FIGURES 12A AND 128 FIGS. 12A and 1213, taken. together; illustrate a two-slip anchor assembly generally designated by the reference character 304. The anchorassenibly 304 includes a mandrel 306 that extends downwardly therethrough. The upper end of the mandrel 306 is provided with a thread 308 arranged for connection with a tubing string (not shown) used to move the anchor assembly 304 in a well bore or through the conduit 201 (see FIG. 13). The lower end of the mandrel 306 includes a thread 310 for connecting the anchor assembly 304 to other apparatus disposedwithin the well bore below the anchor assembly.

Near its lower end portion and on the exterior thereof, the mandrel 306 is provided with a .l-slot 312 that is constructed like the J-slot 208 of FIG. 9. Near its medial portion, the mandrel 306 includes an outwardly projecting flange 314. The purpose of the flange 314 will become more evident as the description proceeds.

The .l-slot 312 isarranged to receive a shear screw or pin 316 that is mounted in a drag spring assembly 318. The drag spring assembly 318 includes a drag spring body 320 having a plurality of resilient drag springs 322 arranged on the exterior thereof. The drag springs 322 frictionally engage the conduit 201.

The drag spring body 320 includes an upper end or abutment 324 and has an annular recess in the upper end forming a downwardly facing shoulder 326 and an upwardly facing shoulder 328. A corrugated spring 330 is located in the annular recess in engagement with the upwardly facing shoulder 328. An annular flange 332 located on the lower end of a lower slip sleeve 334 is disposed inthe annular recess and in engagement with the downwardly facing shoulder 326.

i The lower slip sleeve 334 extends upwardly through a bore 336 of a lower slip 338. The lower slip sleeve 334 slidingly encircles the mandrel 306 and has an annular flange 340 on the upper end thereof.

The bore 3360f the lower slip 338 is constructed in the same manner as was the bore or opening 104 in the slip shown in FIG. 5.

The lower slip 338 includes a lower end 342 and an upper end 344. As shown in FIG. 128, the upper and lower ends 344 and 342, respectively, are located in angularly disposed planes. The lower end 342 includes surfaces 345 for purposes that will become evident hereinafter.

Adjacent the upper end 344 of the slip 338 there is provided a toothed wall gripping portion 346. The teeth on the gripping portion 346 are oriented in a downward direction to prevent movement of the anchor assembly 304 downwardly when disposed in the conduit 201. The lower slip 338 carries leaf springs 348 that engage the exterior of the lower slip sleeve 334 to bias the lower slip 338 toward the retracted position as shown in FIG. 12B. A lower slip 338 also includes a second wall engaging portion 350 located adjacent the lower end 342. The wall engaging portion 350 does not include teeth. It has been found that a slip constructed in accordance with the invention will hold without teeth, but the teeth on one portion assures an adequate holding force without slipping.

Pivot pins 352 carried by the lower slip 338 extend into slots 354 that are located in the lower slip sleeve 334. As previously mentioned, the flange'332 on the lower slip sleeve 334 engages the spring 330, so that the spring 330 holds the lower end 342 out of engagement with the abutment 329 to permit the lower slip 338 to pivot more easily toward the holding position.

The. annular flange 340 on the upper end of the lower slip sleeve'334 is engageable with a flange 356 formed on the lower end of an upper head assembly358, that is, on a head assembly body 359. A downwardly facing abutment 360 on the lower end of the. head assembly body 359 is arranged to engage the upper end 344 of the lower slip 338. Near its intermediate portion, the head assembly body 359 is provided with an interior flange 362. that is engageable with the flange 314 carried by the mandrel 306 for purposes that will become more apparent hereinafter. An upper interior flange 364 on the head assembly body 359 is also engageable with the flange 314 on the mandrel 306 to prevent engagement of the shut ment 360 with the lower slip 338 as the anchor assembly 304 is being lowered into the well bore.

A plurality of retainer screws 366, which are secured in the head assembly body 359, extend through apertures 368 in a movable head member 370 that encircles the upper end of the body 359. The aperture and retainer screw arrangement permits the movable head member 370 to move axially to a limited extent with respect to the head assembly body 359.

Positioned within the head member 370 are a plurality of segments 372 that slidingly encircle the mandrel 306. A garter spring 374 retains the segments 372 resiliently on the mandrel 306.

Each of the segments 372 includes a downwardly facing tapered surface 376 that is engageable with a mating upwardly facing tapered surface 378 on the body 359. Similarly, each of the segments includes an upwardly facing tapered surface 380 that mates with a downwardly facing tapered surface 382 on the interior of the upper head member 370. The upper head member 370 includes an upwardly facing abutment 38 that is engageable with a lower end 386 on an upper slip 388.

The upper slip 388 includes a toothed. wall engaging portion 390 adjacent the lower end 386 and a smooth wall engaging portion 392 adjacent an upper end 394. The teeth on the portion 392 are oriented in an upward direction to prevent up ward. movement of the anchor assembly 304 when the upper slip 388 is in the holding position.

The upper slip 388' also has a bore 396 extending 'therethrough slidably and pivotally positioning the upper slip 388 on an upper slip sleeve 398. A downwardly facing shoulder 400 on the upper slip 388 is engageable with a lug 402 carried by the upper slip sleeve 398. Pivot pins 404cm- 13 ried by the upper slip 388 exr'ern into slots 406 formed in the upper slip sleeve 398 to pivotally support-the upper slip 388 on the anchor assembly 304.

The upper slip sleeve 398, in addition to the lug 402, includes an elongated lower end portion 408 that is adapted to extend into the movable head member 370 and into engagement with the segments 372 for purposes that will be explained more fully hereinafter. At its upper end, the upper slip sleeve 398 includes a flange 410 that is engageable with the lower end 412 of a spring housing 414; Y

The springhousing 414 is connected to a forms a part of the mandrel 306. A coil spring 416 is disposed within the spring housing 414. The lower end of the coil spring 416 is in engagement with the flange 410 on the upper' slip sleeve 398 and the upper end of the coil spring 416 is in engagement with the upper end of s the spring housing 414 thereby exerting a downwardly directed force on the upper slip sleeve 398.

EMBODIMENT OF FIGURES 12A AND 12B OPERATION or THE [connected by the thread 308 to a tubing string (not shown).

The various components of the anchor assembly 304 will be in the positions illustrated in FIG. 12A and 1213 as the anchor assembly 304 is run into the conduit 201.

As shown therein, the upper slip 388 is retained in the retracted position by the engagement of the downwardly facing shoulder 400 with the lug 402 on the upper slip sleeve 398. The leaf spring 348 also biases the upper slip 388 toward the retracted position as illustrated. The head assembly 358 cannot move upwardly into engagement with the upper slip 388 due to the engagement of the flange. 340 on the lower slip sleeve 334 with the flange 356 on the head assembly body 359.

The lower slip-sleeve 334 is prevented from moving upwardly due to the engagement of the flange 332 on the lower end thereof with the downwardly. facing shoulder 326 in the drag spring body 320. As clearly illustrated in FIG. 128, the shear pin 3l6is disposed in the J-slot 312 in engagement with the mandrel 306 thereby preventing the drag spring assembly 318 from moving upwardly. Thus, all the components of the anchor assembly 304 are locked in the positions illustrated in FIGS. 12A and 128 as the anchor assembly 304 is lowered into the conduit 201. A

Upon reaching the desired location in the well bore for setting the anchor assembly 304, rotation is imparted to the tubing string (not shown) and to the connected mandrel 306 while raising and then lowering the mandrel 306 so that the shear pin 316 moves through the elongated portion of the .1- slot 312 as was described in connection with the J-slot and pin arrangement shown in the layout of FlG.-9.

As the mandrel 306 is lowered relative to the drag spring assembly 318, which is retained in a relatively-fixed position due to the frictional engagement between the drag springs 322 and the interior wall of the conduit 201, the flange 314 on the mandrel 306 engages the interior flange 362'in the upper head assembly 358. The engagement therebetween moves the head assembly 358 downwardly until the lower abutment 360 thereon engages the upper end 344 of the lower slip 338. When this engagement occurs, the lower slip 338 is rotated or pivoted about the pins 352 into the holding position, that is, into the position wherein the toothed, gripping surface 346 is firmly engaged with the interior wall of the conduit 201.

When the lower slip 338 is disposed in the holding position, downward movement of the head assembly 358 is no longer possible. At this time or simultaneouslywith a portion of the foregoing, the upper slip sleeve 398 is moved downwardly relative to the upper head assembly 358 andthe lower end 408 thereof enters the movable head member 370. As the lower end 408 enters the movable head 370, it engages the segments 372, moving the segments 372 radially outwardly against the force of the spring 374. As the segments 372 move outwardly, the tapered surfaces 376 and 380 thereon engage the mating tapered surfaces 378 and 382 locking the movable head member 370 in the position illustrated in FIG. 13.

Simultaneously, the lug 402 on the upper slip sleeve 398 has moved away from the downwardly facing shoulder 400 in the upper slip 388. The upper slip 388 is also carried downwardly due to the engagement of the pins 404, with the upper slip sleeve 398 at the top end of the slots 406. The downward movement of the upper slip 388 brings the lower surface 386 thereon into engagement with the abutment 384 on the head member 370 and rotates or pivots the upper slip 388 into the holding position as illustrated in H6. '13. Thus, the lower slip 338 is disposed in firm holding engagement with the conduit 201 and the upper slip 388 is locked into holding engagement with the conduit 201. The arrangement of the .teeth on the slips 338 and 388 prevent movement of the anchor assembly 304 in either the upward or downward direction in the conduit 201.

When it is desired to retrieve the anchor assembly 304 from the well bore, rotation, in the opposite direction, is imparted to the mandrel 306 while simultaneously raising the mandrel 306 to return the pin 316 to the lower portion of the J-slot 312. As the mandrel 306 is raised, the lower end 412 on the spring housing 414 again engages the flange 410 on the upper slip sleeve 398, pulling the upper slip sleeve 398 upwardly therewith. As the upper slip sleeve 398 moves upwardly, the lower end 408 thereon moves-out from under the segments 372, permitting the spring 374 to return the segments 372 to position illustrated in FIG. 12A. When this occurs, the movable head member 370 is free to move downwardly relative to the retaining screws 366, thus moving the abutment 384 away from the lower end 386 of the upper slip 388.

While the movable head arrangement has been described in connection with the anchor assembly 304, it will be apparent that the arrangement can be used with any of the anchors and packers described herein. The main purpose of the arrangement is to reduce the force required to return the engaged slip to the retracted position.

if the upper slip 388 is not wedged too tightly in the conduit 201, the leaf spring 348 will return the upper slip 388 to the retracted position as illustrated in FIG. 12A. if the upper slip 388 is wedged tightly into the conduit 201, the movement of the upper slip 388 to the retracted position may not occur until lug 402 on the upper slip sleeve 398 engages the downwardly facing should 400 in the upper slip 388. Upon engagement between the lug 402 andthe shoulder 400, a moment is imparted to the upper slip 388 that will positively disengage the upper slip 388 from the conduit 201 and return it to the retracted position.

The flange 314 on the mandrel 306 is also moved upwardly until it engages the flange 364 on the upper end of the upper head assembly 358. When this occurs, the upper head body 359 is moved upwardly moving the lower abutment 360 thereon out of engagement with the upper end 344 of the lower slip 338. The lower slip 338 is then free to pivot under the urging of the springs 348 into the retracted position as illustrated in FIG. 12B.

To be certain that the lower slip 338 does return to the retracted position, the lower flange'356 in the upper head body 358 engages the flange 340 on the lower slip sleeve 334, carrying the lower slip sleeve 334 upwardly therewith. As previously described, the flange 332 on the lower end of the lower slip sleeve 334 is in engagement with the drag spring body 320 so that the drag spring 320 is carried upwardly therewith. If the lower slip 338 has not returned to the retracted position, the abutment 324 on the upper end of the drag spring body 320 engages the surfaces 345 on the lower slip 338 to create a moment on the lower slip 338, rotating it about the pivot pins 352 into the retracted position. Upon release of the lower slip 338 the anchor assembly 304 is returned to the condition wherein it can be retrieved from the conduit 2.01.

A safety release feature is built into the anchor assembly 304 as was built into the packer assembly 200. That is, the shear pin 316 will part if sufficient upward force is exerted on the mandrel 306, permitting the relative upward movement of the various components to occur even though proper rotation and release of the .I-slot and pin arrangement cannot be accomplished. The anchor assembly 304 can be retrieved as previously described after the shear pin 316 has been parted.

DESCRIPTION OF THE EMBODIMENT OF FIGURES 15A,

15B, AND 15C FIGS. 15A, 15B, and 15C taken together comprise a hydraulically-actuated packer assembly that is generally designated by the reference character 420. The packer assembly 420 includes a mandrel 422 having a thread 424 at its upper end arranged for connection with a tubing string (not shown) that is used to move the packer assembly 420 through a well bore or conduit 201. The lower end of the packer assembly 420 is threadedly connected with a valve nipple 425.

The valve nipple 425 has an annular valve seat 426 on the interior thereof. The valve seat 426 is provided to sealingly receive a valve ball 427 (see FIG. 16C) so that hydraulic pressure can be applied to the packer assembly 420. The lower end of the landing nipple 425 is provided with a thread 428 whereby other apparatus can be attached thereto below the packer assembly 420.

As shown in FIG. 15C, a shear screw or pin 430 connects a lower head assembly 432 with the mandrel 422. The lower head assembly 432 has an annular recess in the upper interior end thereof providing a downwardly facing shoulder 434 and an upwardly facing shoulder 436. A flange 438 on the lower end of a lower slip sleeve 440 is disposed in the annular recess in engagement with the downwardly facing shoulder 434. A corrugated annular spring 442 is located in the annular recess between the flange 438 and the upwardly facing shoulder 436 to bias the lower slip sleeve 440 relatively upwardly.

The lower slip sleeve 440 extends upwardly from the lower head assembly 432 through a bore 444 in a lower slip 446. A flange 448 on the upper end of the lower slip sleeve 440 is engageable with a lower end 450 of a piston 452. Slots 454 in the lower slip sleeve 440 are arranged to receive pivot pins 456 carried by the lower slip 446 so that the lower slip 446 is pivotally carried by the lower slip sleeve 440.

The bore 444 in the lower slip 446 is preferably constructed as is the bore 104 in the slip 100 previously discussed. The lower slip 446 has a lower end 458 disposed adjacent, but in spaced relationship to the upper end of the lower head assembly 432. The spring 442 biases the lower slip sleeve 440 upwardly and the sleeve 440, through the pivot pins 456, holds the lower end 458 away from the head assembly 432.

Adjacent the lower end 458 of the lower slip 446, there is provided a toothed, wall gripping portion 460. The teeth on the portion 460 are oriented in a downward direction to prevent movement of the packer assembly 420 downwardly in the well bore when the lower slip 446 is in the holding position.

A toothed, wall gripping portion 462 is disposed adjacent an upper end 464 of the lower slip 446. The teeth on the portion 462 are also oriented in a downward direction. A lower end 458 of the lower slip 446 includes surfaces 466 that are offset from the pivot pins 456 for reasons that will be described more fully hereinafter.

Leaf springs 468 have one end secured to relatively opposite sides of the lower slip 446. The free ends of the springs 468 engage the lower slip sleeve 440 to bias the lower slip 446 about the pivot pins 456 toward the retracted position of the slip 446 as illustrated in FIG. 15C.

As shown in FIG. 153, the piston 452 slidingly encircles the lower slip sleeve 440 and the mandrel 422 and a portion of the piston 452 extends upwardly into a cylinder 470. As the packer assembly 420 is lowered into the well bore, the piston 452 and cylinder 470 are prevented from moving relative to each other by a shear screw or pin 472 that is carried by the cylinder 470 and extends into the piston 452.

A split-ring retainer 474 having teeth on the interior thereof is disposed between a downwardly fading tapered surface 476 in the cylinder 470 and the piston 452. The retainer 474 is arranged to permit the piston 452 to move downwardly relative to the cylinder 470 but to wedge between the cylinder 470 and piston 452 to prevent upward movement of the piston 452 relative to the cylinder 470.

The upper end of the piston 452 is provided with an external seal 478 that slidingly and sealingly engages the cylinder 470 and an internal seal 480 that slidingly and sealingly engages the mandrel 422. A seal 482 carried by the cylinder 470, relatively above the seals 478 and 480, slidinglyand sealingly engages the mandrel 422 forming a chamber 484 therebetween. A pressure port 486 extends through the mandrel 422 providing communication between the interior of the mandrel 422 and the chamber 484.

To prevent relative movement between the mandrel 422 and the cylinder 470 as the packer assembly 420 is lowered into the well bore, a plurality of locking dogs 488 are located between the cylinder 470 and the mandrel 422. A lower end 490 on each of the locking dogs 488 extends into a recess 492 formed in the exterior of the mandrel 422. A lug 494 on each of the locking dogs 488 extends into a recess 496 formed in the cylinder 470. A garter spring encircles the dogs 488 resiliently biasing the lower ends 490 thereon into the recess 492.

A projection 500 formed on the upper end of the piston 452 also engages the lower end 490 of the dogs 488 to hold the lower end 490 in the recess 492 during the lowering of the packer assembly 420 into the well bore. Thus, the cylinder 470 is secured to the mandrel 422 and the piston 452 is also secured to the mandrel 422 thereby preventing relative move ment therebetween and preventing inadvertent setting of the packer assembly 420 as it is lowered into the well bore.

Referring to FIG. 15A, it can be seen that the upper end of the cylinder 470 is in engagement with the lower most of a plurality of deformable packing elements 502. While illustrated as a series of stacked packing elements 502 and spacers 504, any suitable form of deformable packing can be utilized in the packer assembly 420. The packing elements 502 are carried by a packing shell 506. The lower end of the shell 506 is slidably received in the upper end of the cylinder 470. A flange 508 on the lower end of the packing shell 506 is engageable with the interior of the upper end of the cylinder 470.

The packing shell 506 slidingly encircles the mandrel 422 and is spaced therefrom to form a passageway 510. The passageway 510, ports 512 in the cylinder 470 and ports 514 in an upper head 516 form a bypass passageway to permit fluid to flow by the packing elements 502 and through the packer assembly 420 between the packing shell 506 and the mandrel 422.

The packing shell 506 is threadedly connected at its upper end with the upper head 516. The upper head 516 includes an abutment 517 that is in engagement with the topmost of the packing elements 502.

An interior flange 518 in the upper head 516 is arranged to engage a pickup ring 520 carried by the mandrel 422.

The upper head 516 also carries a resilient bypass valve element 522 that is engageable with the exterior of the mandrel 422 during setting of the packer assembly 420 to close and. thus, prevent fluid flow through the passageway 510. The upper head 516 also includes an upper end 524 that is engageable with a lower end 526 on an upper slip 528.

Adjacent the lower end 526 of the upper slip 528 there is provided a toothed, wall gripping portion 530. The teeth on the portion 530 are oriented in an upward direction to prevent upward movement of the packer assembly 420 in the well bore when the packer assembly 420 is set therein. Also, the upper slip 528 is provided with a wall gripping portion 532 located adjacent an upper end 534. The portion 532 has teeth thereon that are also oriented in a upward direction to prevent movement of the packer assembly 420 upwardly.

carried by an upper slip sleeve 540. The lug 538, when in engagement with the shoulder 536, prevents movement of the upper slip 528 from the retracted position into the holding position and functions to return the slip 528 to the retracted position from theholding position as will be described.

The upper slip 528 is also provided with a leaf'spring 539. The spring 539 engages an upper slip sleeve 540 to bias the upper slip 528 toward the retracted position. Pivot pins 542, carried by the upper slip 528, are located in slots 544 located in the upper slip sleeve 540. Y

The upper end of the upper slip sleeve 540 includes a flange 546 that is" disposed within a recovery "sleeve 548. The recovery sleeve 548 is attached to the mandrel 422 and is in engagement with the flange 546 on the upper'slip sleeve 540 so that the upper slip sleeve 540 moves with the mandrel 422.

OPERATION OF THE EMBODIMENT OF FIGURES A,

' 15B, AND 15c;

FIGS. 15A, 15B, and 15C, taken together, illustrate the various components of theipacker assembly 420 in the positions they occupy during lowering of the packer assembly 420 into the well bore. The lower head assembly 432 is retained on the mandrel 422 by the shear pin 430. The lower slip sleeve 440 is pulled into the well-bore with the lower head assembly 432 due to the engagement between the lower flange 438 on the lower slip sleeve 440 and the downwardly facing shoulder 434 in the lower head assembly 432.

While the lower slip 446 vcan move upwardlyon the lower slip sleeve 440, its upward movement is limited by the engagement of the pins 456 with the lower slip sleeve 440 at the top end of the slots454. The leaf springs 468 on the lower slip 446 retain the lower slip 446 in the retracted position illustrated in FIG. 15C. 1

, The flange 448 on the upper end of the lower slip sleeve 440 is in engagement with the lower end 450 of the piston 452, carrying the piston 452 into the well bore therewith. The shear pin 472 locks the piston 452 and the cylinder 470 together so that the cylinder 470 is also pulled into the well bore with the piston 452 and mandrel 422. The cylinder 470 is locked against movement relative to the mandrel 422 by the locking dogs 488 as previously described The upper end of the cylinder 470 is in engagement with the flange 508 on:the lower end of the packing shell 506 thereby pulling the packing shell 506, the packing elements 502 and the attached upper head .516 into the well bore. The'upper slip .528 is prevented-from moving downwardly into engagement with the upperend 524 of the upper head '516 by the engagement of the lug 538 on the upper slip sleeve 540 with the downwardly facing shoulder 536 in the upper slip 528. If fluid flow should cause the upper slip 528 to move upwardly relative to the upper slip sleeve 540, the spring 539 carried by the upper slip 528 prevents rotation of the upper slip 528 into the holding position.

The position of the upper slip sleeve 540 is fixed relative to the mandrel 422 by the engagement of the recovery sleeve 548 with the flange 546 on the upper end of the upper slip sleeve 540. As can be appreciated from the foregoing, the various components of the packer assembly-420 are securely retained in the unset or retracted position as the packer as sembly 420 is lowered into the well bore.

As the packer assembly 420 is lowered, the bypass valve element 522 is out of engagement with the mandrel 422 and the passageway 510 is'open. Fluid in the well bore can pass upwardly, entering the ports 512, flowing through the passageway 510 between the mandrel 422 and packing shell 506, and outwardly through the ports 514; The fluid thus bypasses the packing elements 502, permitting the packer assembly 420 to be lowered at a higher rate of speed and reducing the possibility of washing one or more of the packing elements 502 off the packer assembly 420.

Upon reaching setting depth in the well bore, the valve ball 427 or other suitableclosing device is dropped into the tubing string (not shown). The valve ball 427 passes downwardly through the tubing string and mandrel 422 until it lands on the annular valve seat 426 in the valve nipple 425.

When the valve ball 427 lands on the seat 426, the interior of the mandrel 422 is closed and fluid pressure can be applied to the packer assembly 420. The pressure in the mandrel 422 is exerted through the pressure ports 486 in the mandrel 422 into the chamber 484 formed by the piston 452, mandrel 422 and cylinder 470. As the pressure builds up in the chamber 484, a force is applied to the piston 452 and to the cylinder 470. When the applied force reaches a sufficiently high magnitude, the shear pin 472 parts, as illustrated in F lGS. 16B and 16C, permitting the piston 452 to move downwardly.

' The locking dogs 488, which are located in the recess 492 in the mandrel 422, prevent upward movement of the cylinder 470. When the piston 452 moves downwardly, the locking dogs 488 are free to move out of the recess 492. The cylinder 470 then moves upwardly forcing the locking dogs 488 out of the recess 492.

As the piston 452 moves downwardly, the lower end 450 thereon engages the upper end 464 of the lower slip 446, pivoting the lower slip 446 into the holding position illustrated in FIG. 16C. When the slip. 446 reaches the holding position, the teeth on the gripping portions 460 and 462 securely engage the interior of the conduit 20,1, preventing downward movement of the lower slip 446 and piston 452.

With the lower slip thus fixed relative to the conduit 201, the pressure in the chamber 484 drives the cylinder 470 upwardly until the upper end 524 on the upper head 516 engages the lower end 526 of the upper slip 528. The engagement therebetween pivots the upper slip 528 into the holding position illustrated in FIG. 16A. in this position, the teeth on the gripping portions 530 and 532 of the upper slip 528 are securely engaged with the conduit 201 and prevent upward movement of the upper slip 528 and upper head 516.

- The upward movement of the cylinder 470 and upper head 516 carries the bypass valve element 522 upwardly and into sealing engagement with the mandrel 422. When the valve element '522 engages the mandrel 422, the passageway 510 is closed, preventing fluid flow between the packing shell 50.6 and mandrel 422.

Additional pressure applied in the chamber 484 causes the upward movement of the cylinder 470 to continue. It will be noted that the upper end of the cylinder 470 engages the lowermost of the packing elements 502 while the now fixed lower abutment 517 on the upper head 516 is in engagement with the uppermost of the packing elements'502. Since the cylinder 470 is moving upwardly relative to the abutment 517, the packing elements 502 are deformed outwardly until they are in sealing engagement with the conduit 201. The packer assembly 420 is now in the fully set position in the conduit 201.

The annular valve seat 426 in the valve nipple 425 is constructed so that a predetermined pressure will shear the valve seat 426 out of the valve nipple 425, permitting the ball 427 to move downwardly into the well bore. When the valve seat 427 and ball 425 are forced downwardly, the bore extending through the packer assembly 420 is completely open and any desired operations can be performed below the packer assembly 420.

If, after setting the packer assembly 420, the pressure is reduced in the mandrel 422 and consequently in the chamber 484, the various components of the packer assembly 420 are retained in the set condition as illustrated in FIGS. 16A, 16B and 16C. Maintaining the packer assembly 420 set, after the pressure is reduced, is accomplished through the split ring retainer 474. The split ring retainer 474, while permitting movement of the piston 452 downwardly relative to the cylinder 470, prevents the upward movement of the piston 452 relative tothe cylinder 470 since the split ring retainer 474 wedges against the tapered surface 476 in the cylinder

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