US2189697A - Cement retainer - Google Patents

Description

Feb. 6, 1940.

R. C. BAKER CEMENT RETAINER Filed March 20, 1939 INVENTOR. REUBEN Cf BAKER ca/s, Q. m

ATTORNEY Patented Feb. 6, 1940 UNITED STATES PATENT OFFICE Baker Oil Tools, Inc.,

Huntington Park, Calii'.,

a corporation of California Application March 20, 1939, Serial No. 262,849

18 Claims.

Tiis invention relates to that general type of well devices commonly known as cement retainers and which have particular utility in oil well practice for packing ofi a well casing at any 5 selected point.

Devices of this general character usually comprise a tubular body internally screw threaded at its upper end for attachmentto the lower end of a run-in string of tubing, it being required that such screw-threaded connection make a fluid tight joint and at the same time be of such character as to permit an unscrewing of the run-in string from the anchored device by rotation of said string without danger of loosening any of the standard screw-threaded joints of the balance of said run-in string. However, in practice it has been demonstrated that such screw-threaded connection will not always loosen under the rotative strain usually applied to the run-in string at the derrick floor, thus making it necessary to apply an abnormal rotative strain in an attempt to release the run-in string from the anchored retainer, with the result that in numerous instances an expensive fishing or drilling job has been 25 casioned by a twisting apart of the run-in string.

It is, therefore, the principal object of the present invention to provide an improved device of the character referred to, which may be lowered into a well casing to a position of use by means of a setting tool or flow mandrel forming the lower terminal end of a run-in string of tubing and which may thereafter be set in such position without further manipulation of the tubing string and entirely by the pressure of a fluid or gas pumped down said tubing string; to normally connect the setting tool or flow mandrel to the cement retainer or packing device in such a manner that it may be disconnected from the set device without the necessity of rotating the run-in string; and to provide a releasable means for protecting the device while being lowered into the well casing; the device providing a well packer adapted for use in various situations requiring a set or anchored packer 5 and being particularly adaptable for use as a bridge plug in any situation in which it is necessary or desirable to bridge a well casing.

In general, the apparatus comprises a tubular packing device adapted to be lowered in a well casing to a position of use, by means of a setting tool or flow mandrel forming the lower end portion of a run-in string of tubing, said packing device including in its structure casing gripping means for anchoring it in the casing against 5 dislodgment by pressure to which it may be subjected and packing means expansible to fluid tight sealing engagement with the casing wall. said anchoring and said packing means both being operable entirely by the pressure of fluid or gas pumped down the run-in string to set the 5 device, -so that manipulation of the tubing string is not required for the setting operation, and the setting tool or flow mandrel being normally secured to the packing device by shear elements enabling said tool or mandrel to be pulled loose from the set device without necessity of rotating the run-in tubing string.

When the setting tool or flow mandrel is thus pulled loose from the set device, the entire tubing string will be withdrawn from the well casing, leaving therein said set device which will later be drilled up in a subsequent drilling operation. The cement retainer, or packing device is, for this reason, constructed of readily drillable materials.

The invention also contemplates a protecting means, one embodiment which such means may assume being of a character suchas is disclosed in my United States Letters Patent No. 2,150,310, issued March 14, 1939, titled "Protective means for deep well packers, to which patent reference may be had for a more detailed description thereof.

Generally, the protecting means herein disclosed is in the form of an enclosing jacket or sheet metal can which is yieldingly retained on the device and arranged to be forced therefrom by the pressure of fluid or gas pumped down the tubing string, after the device reaches its position of use and before the setting thereof in the well casing.

The invention is exemplified in the following description and illustrated by way of example in the accompanying drawing in which:

Fig. 1 is a longitudinal sectional view through a portion of a well casing and disclosing one form of embodiment of the apparatus of the present invention, partly in section and partly in elevation, withthe parts in the positions they assume when said apparatus is being run-in the casing.

Fig. 2 is a view, similar to Fig. 1, but showing the several parts in the positions they assume when the device is fully set and firmly anchored in place in the casing.

Fig. 3 is a view, similar to Fig. 2, but showing the set device as it will appear after the setting tool or flow mandrel has been pulled loose therefrom and removed by withdrawal of the tubing string from the casing.

Although the device may be employed as a packer for various purposes, it will first be de- 68 scribed in detail with reference to its use as a cement retainer and bridge plug.

Referring to Fig. 1 of the drawing, A designates the cement retainer as it is normally enclosed in the protective jacket B and connected to the setting tool or flow mandrel C forming the lower terminal end portion of the tubing string D by means of which the retainer is lowered through the well casing E to its position of use, it being understood that the retainer is of general tubular character, cylindrical in cross section, and with its enclosing protective jacket, is of a normal overall external diameter Just slightly less than the internal diame pf the well casing in which itistoberunan set.

The retainer proper includes a hollow cylindrical body Ill having an axial bore of uniform diameter, the upper portion of the wall ofsaid bore being angled upwardly andoutwardly to provide a flared receiving throat and said angled wall being circularly grooved to form an internal abutment shoulder II. The upper end portion of the body In is formed to provide a relatively stationary, upwardly and outwardly tapered slip-expanding cone l2, and below said upper cone the body is reduced in external diameter and is circularly grooved to provide a vertical series of ratchet teeth I3.

Since it is desired to set the retainer in the casing in a manner which will prevent either downward or upward displacement of the set retainer, said retainer has incorporated in its structurea circularly disposed series of down-gripping casing slips l4 and a circularly disposed series of upgripping casing slips l5. The upper slips l4 have tapered inner surfaces complemental to the tapered outer surface of the slip expanding cone l2 and each thereof is normally disposed in collapsed position with its upper end portion attached to said cone by one or more shear screws IS, the several slips |4 thus being normally retained in collapsed condition by means capable of being disabled upon subse-' quent upward translation of said slips relative to the slip expanding cone l2.

Immediately below the slips l4 and surrounding the body I0 is an upper packing assembly axially "translatable on said body and comprising a compressible packing sleeve l8 which is disposed between upper and lower slip-engaging packingexpanding ring members l9 and 20, respectively.

The lower slips I 5 are disposed immediately below the lower ring member and are of the same form as the upper slips I4, but are reversely positioned so that their wickers or gripping teeth point upwardly and their inner surfaces taper upwardly and inwardly. Co-operating with these lower slips and slid-ably mounted on the body In is a lower packing assembly which constitutes the means for axially translating all of the slips and the intermediate upper packing assembly to effect expansion of the several slips to casing gripping positions and to axially compress and radially expand said upper packing to fluid tight engagement with the casing wall. This lower packing assembly includes a lower packing 2| of cup form having an inner annular lip 22 and an outer annular lip 23 spaced from said inner lip, and a lower slip-expanding annular cone 24 providing an upwardly and inwardly tapered external surface complemental to the inner tapered surfaces of the several lower slips l5. Each of said slips is normally disposed in collapsed position with its lower end portion attached to the cone 24 by one or more shear screws 25, the several lower slips I! being thus normally supported on said cone and retained in collapsed condition by means capable of being disabled upon subsequent upward translation of said cone relative to the lower slips.

It will be pointed out that the several shear screws 25 of the lower slips I! have a greater shear value than have the several shear screws it of the upper slips l4, so that, in a setting operation, the shear screws I6 of the upper slips will be sheared prior to a shearing of the shear screws 25 of said lower slips.

It is desirable that the packing cup 2| be connectedto the cone 24 by interlocking means and to this end the lower edge of said cone and the upper edge of said cup are of companion contour, the cone being provided with an internal annular flange 26 defining an adjacent internal groove, and the cup having an external annular head 21 disposed in said groove and defining an adjacent external groove accommodating said flange.

The lower packing cup 2| ispreferably formed of relatively tough rubber or other suitable material of a nature having sufficient resiliency to cause the outer marginal lip 23, when released from restraint, to flex outwardly and engage the casing wall. It is also preferable to form the upper packing sleeve I8 of relatively tough rubber or other suitable material having sufficient initial rigidity to transmit the force necessary to shear the shear screws IE or at least of suilicient compressive resistance to effect such shearing of said screws before said packing becomes so tightly packed between the retainer body and casing wall as to arrest the axial translation of this upper packing assembly.

The lower packing assembly is normally restrained against axial translation by two shear screws 28 connecting the lower 'cone 24 to the body l0, these shear screws 28 having a combined shear value which is less than that of the several shear screws l6 of the upper slips |4, so as to be sheared prior to a release of the upper slips by a shearing of their retaining shear screws l6.

To retain the lower cone 24 and its associated cup packing in an upper actuated position, said cone is provided with a one-way ratchet latch comprising a contractile split ring 29 of substantially saw-tooth cross sectional contour with its inner face angled upwardly and outwardly and its lower face disposed transversely to the longitudinal axis of the device. This latch ring is disposed within an internal groove formed in the cone 24 and will, when said cone is elevated, co-operate with the ratchet teeth l3 of the body Hi to prevent reverse movement of the cone.

Below the lower packing assembly, the body I0 is provided with a plurality of circularly spaced horizontally aligned lateral discharge ports 30 formed in its side wall, and to control these discharge ports I provide a back-pressure valve 3| in the form of a flexible sleeve, preferably formed of resilient rubber, which surrounds the body in position to normally close said ports, the upper end of said sleeve being secured to an externally screw-threaded portion of the body by means of a co-operating internally screw threaded gland 32 so as to permit the unsecured skirt portion of the valve to be flexed outwardly by a predominate internal pressure, thus opening the several discharge ports 30.

ing or jacket B which will serve not only as a means of protecting the retainer while it is being run in the casing, but will also protect the retainer during transportation to a well and while on an outdoor tool rack or other place of storage while awaiting use in a well.

In practice, the protecting housing B may be applied to the retainer A prior to shipment thereof or it may be applied at the well site either before or after it is connected to the tubing string and before being run in the well casing. Preferably, said housing comprises a cylindrical shell or can formed of relatively thin sheet metal, such as galvanized iron, and has a lower end of inverted truncated cone shape tending to guide the housing and its contained device safely down the well. Above its lower cone end, this shell or housing B is normally undeformed and is of uniform diameter so that it may readily be slipped over the cement retainer A, and is of such length that its upper rim portion will initially extend slightly above the top of the contained cement retainer. To retain the housing B on the cement retainer A, against accidental displacement or removal therefrom, I form the upper rim thereof with suitable releasable retaining means. In the present instance, I vertically slit the upper rim portion at circularly spaced intervals to form a series of tangs, and after the housing is in place, I bend each alternate tang 33 inwardly and downwardly over the upper marginal edge of the retainer.

The bottom wall of the housing B has an inlet opening 34 formed therein and defining a valve seat, and is provided with an inlet valve 35 arranged to co-operate with said valve seat. While various forms of valves may be employed for preventing outward flow of fluid through the opening 34, I prefer to use a flapper type valve formed of flexible material, such as rubber or leather, and secured at one end to the bottom wall with its free end provided with a suitable reinforcing weight disc 36.

The setting tool or flow mandrel C and the runin string of tubing of which it is a part, forms the means for lowering the cement retainer into a well casing and of conveying the actuating fluid to the discharge ports 30 of the retainer for the retainer setting operation and of subsequently conveying the cement slurry to said ports for discharge therethrough in a cementing operation.

While the entire mandrel C is illustrated as a two part structure comprising an upper coupling member 3'! and a depending hollow cylindrical flow nozzle or tail-pipe 38, screw-threaded together, this is mainly for the purpose of eflecting a saving of stock and for reducing the cost of machining during manufacture, it being obvious that, if desired, said mandrel structure may be formed as an integral unit.

In the preferred form shown in the drawing, the lower end of the coupling member 31 is formed to provide an annular transverse stop shoulder 39 adapted to engage the abutment shoulder I I formed on the body of the cement retainer, and formed in the side wall of said coupling member, adjacent said stop shoulder, is an annular groove 40 which, when the retainer is connected to the mandrel, will receive the inner ends of two shear screws 4| by means of which the cement retainer is initially dependingly hung on the mandrel. The bore of this coupling member 3! has an internally screw-threaded upper end adapting said coupling for attachment to the lower screw-threaded end of the tubing string D, the lower end of said diameter and internally screw-threaded to receive the upper screw-threaded end of the flow nozzle 38 which will be tightly screwed therein.

The flow nozzle 38, throughout the greater portion of its length, is of an external diameter somewhat less than the internal diameter of the axial bore of the body l0, and at its lower end is formed to provide a discharge head 42 of piston-like character which has a closed lower end and is axially slidable within the body bore whenever the mandrel is inserted in or withdrawn from the cement retainer. The medial portion of this discharge head 42 is reduced in diameter as at 43 to form, with the wall of the body Ill, an annular flow chamber which will register with the several discharge ports 30 when the mandrel is disposed in the body bore in its innermost position, as shown in Figs. 1 and 2 of the drawing. Lateral flow ports 44 are formed in the side wall of the discharge head 42 at an elevation to afford communication between the annular flow chamber 43 and the axial flow passage 45 of the mandrel C, and above and below the chamber 43 the discharge head 42 is provided with annular packing grooves in which are positioned similar packing rings 46. These packing rings are. relatively reversely disposed and are of such character as to be equally subjected to the expanding pressure of the circulation fluid or cement slurry and since such packing expanding pressure will be proportional to and vary with variations in the circulation pressure, which is the pressure packed against, it follows that this packing arrangement involves a balanced fluid pressure sealing method which will at all times insure an effective fluid tight seal between the; mandrel and the wallof the bore of the retainer body 10.

As the apparatus, conditioned as shown in Fig. 1, is lowered into a well casing containing fluid, the valve 35 will open to permit the well fluid to enter the protective housing B to counter-balance the external and internal pressures and prevent a collapse of the thin metal housing. When the enclosed cement retainer reaches its position 'of use, fluid is circulated down the tubing string D to flow through the axial flow passage 45 and lateral flow ports 44 of the mandrel Cand into the annular flow chamber 43 and through the discharge ports 30 of the body H] to open the backpressure valve sleeve 3| an'd flow into the lower portion of the housing B below the lower pack ing cup 2!. This pumper fluid will build up a pressure within the housing suflficient to drive said housing off the cement retainer A. The retainer tangs 33 at the upper end of the housing will be straightened by such downward movement to release said housing, which when released, will drop to the bottom of the well bore, and, being constructed of relatively soft thin metal, it may subsequent y be readily side-tracked or drilled up during a later drilling operation, or may later be fished from the well, if desired.

With the proective housing B thus removed from the retainer, the outer marginal lip 23 of the lower cup packing 2| will flex outwardly to engage the casing wall. Circulation will be continued to build up in the casing below the cup packing. a pressure suflicient to shear the shear screws 28 of the lower cone24 and translate upwardly the entire packing and slip structure and eflect a shearing of the shear screws [6 of the upper slips l4. With this upward movement being transmitted through the lower collapsed slips and the upper packing assembly, the upper slips bore being of reduced.

M will be moved upwardly and outwardly on the upper slip expanding cone i2 of the body In to an expanded condition, said upper slips |4 engaging and gripping the wall of the well casing E. As said upper slips are thus set, the upper packing sleeve |8 will be longitudinally compressed between the adjacent slip engaging rings l9 and and laterally expanded to effect a fluid seal between the body ID of the retainer and the casing wall. Continued upward movement of the lower packing assembly relative to the lower slips l5 will shear the shear screws of said lower slips, the lower slip expanding cone 24 then becoming effective to expand the lower slips and cause them to engage and grip the casing wall. The lower packing cup will then be firmly compressed to a degree proportional to the pressure existing below it in the well casing, to effect a second or lower fluid seal. As the lower cone 24 is elevated the contractile ratchet latch ring 29 will co-operate with the ratchet teeth i3 on the body It] to retain said cone in its elevated position.

It will thus be evident that the setting or anchoring and packing of the cement retainer in its position of use in a well casing, will be accomplished entirely by pressure actuated means and without any required manipulation of the run-in string and that the setting operation will involve a series of steps comprising in sequence a setting of the upper or down-gripping slips l4, a compressing and expanding of the upper packing l8 to effect a fluid seal between the upper and lower slips, a setting of the lower up-gripping slips l5, and a final compressing and expanding of the lower cup packing 2| to effect a second or lower fluid seal. However, it will be understood by those skilled in the art that in this setting operation there may be some initial axial compression of both packings which in some instances may even cause them to closely contact the casing wall, but in any event not with such force as to interfere with the above described setting and packing operation.

With the cement retainer A thus set in its position of use, as shown in Fig. 2, a cementing operation may be conducted by pumping down the tubing string D and flow mandrel C, a batch of cement slurry which will discharge through the discharge ports 30 of the retainer and beneath the back-pressure valve 3| into the well casing below the set retainer, the back-pressure valve preventing a reverse flow of the discharged cement slurry.

After completion of the cementing operation, the run-in tubing string may be disengaged from the set retainer merely by pulling upwardly on the tubing string E with suflicient force to shear the connecting shear screws 4| and withdraw the flow mandrel from the bore of the retainer body It]. When thus disengaged from the set retainer the tubing string may be withdrawn from the well casing in which will remain the set retainer, as shown in Fig. 3 of the drawing.

If the set retainer is to be conditioned to function as a bridge plug, a bridging ball F (indicated by broken lines in Fig. 3) will be sent down the well casing to seat in the flared throat of the bore of the retainer body It] and close said bore, after which cement slurry may be pumped down the casing to discharge through perforations or ports formed in the casing wall above the set bridge plug.

In employing the device in repressuring an oil sand, an exhausted well which taps said sand is selected and the packer set therein just above the perforated section of the well casing. Pumping of gas through the set packer and into the well casing below said packer will force the gas into the oil sand to create therein a gas pressure sufficient to drive additional oil into adjacent wells from which it may be pumped to the surface.

As the device may, with the use of the bridging ball F, be used purely as a bridge packing to seal off the interior of the well casing at any point it may be employed to effect a high pressure gas below a above bottom, complete shut off .of producing oil sand.

While I have herein disclosed a preferred form of embodiment of my invention, it is to be understood that various changes may be made therein by those skilled in the art without departing from the spirit of the invention as deflned in the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a device of the character disclosed, the combination of a body adapted to be lowered into a well casing and through which fluid may be pumped, means carried by said body and operable to grip the casing wall, packing means carried by said body and operable to effect a fluid tight seal between said body and the casing wall, said body having an axial bore closed at its lower end and transversely aligned lateral discharge ports formed in its side wall above the lower end of said bore, and a back-pressure valve surrounding said body to normally cover and close said discharge ports against reverse fluid flow therethrough and adapted to be moved by a predominant internal pressure to an open position permitting discharge of the pumped fluid outwardly through said ports.

2. In a device of the character disclosed, the combination of a body adapted to be lowered into a well casing and through which fluid may be pumped, casing gripping slips mounted on said body, slip expanding means on said body and in wedge engagement with said slips, connecting means capable of being disabled normally connecting the slips to said expanding means in ineifective positions, and means operable by fluid pressure built up in the casing exteriorly of said body by the pumped fluid to cause relative movement between said slips and said expanding means to disable said connecting means and expand said slips to gripping engagement with the casing wall.

3. In a device of the character disclosed, the combination of a body adapted to be lowered into a well casing and through which fluid may be pumped, slip expanding means mounted on said body, axially translatable slips normally disposed in ineffective positions in wedge engagement with said expanding means and operable to grip the casing wall, axially translatable packing means disposed on said body to engage said slips and operable to effect a fluid tight seal between said body and the casing wall, said body having an axial bore closed at its lower end and transversely aligned lateral discharge ports formed in its side wall below said packing means, and a back-pressure valve surrounding said body to normally cover verse fluid flow therethrough and adapted to be moved by a predominant internal pressure to an open position permitting discharge of the pumped fluid outwardly through said ports to build up a pressure exteriorly of said body and within the and close said discharge ports against recasing below said packing means to eflect axial translation of said packing means and said slips causing said slips to grip the casing wall and said packing means to form a fluid tight seal between said body and said casing wall. a

4. In a device of the character disclosed, the combination of a body adapted to be lowered into a well casing and through which fluid may be pumped, an upper slip expanding means carried by said body, upper casing gripping slips disposed in wedge engagement with said upper expanding means, upper shear means normally connecting said upper slips to said upper expanding means in inefiective positions, a packing sleeve slidable on said body to translate said upper slips, lower casing gripping slips engaging said packing sleeve, lower slip expanding means disposed in wedge engagement with said lower slips, lower shear means normally connecting said lower slips to said lower expanding means in inefiective positions and having a greater shear value than said upper shear means, and means operable by fluid pressure built up in the casing exteriorly of said body by the pumped fluid to axially translate said lower expanding means, said lower slips, said packing sleeve and said upper slips to shear said upper shear means and expand said upper slips, to then axially compress and radially expand said packing sleeve to form a fluid tight seal between said body and the casing wall and to thereafter shear said lower shear means and axially translate said lower slips to effect expansion of said lower slips.

5. In a device of the character disclosed, the combination of a body adapted to be lowered into a well casing and through which fluid maybe pumped, means operable to anchor said body in said casing, and means translatable on said body by fluid pressure built up in the casing below said device by the pumped fluid to actuate said anchoring means and effect a fluid tight seal between said body and the casing wall.

6. In a device of the character disclosed, the combination of a body having an axial bore and lateral discharge ports communicating therewith, a back-pressure valve normally closing said ports against reverse fluid flow and operable by a predominant internal pressure to an open position permitting outward discharge therethrough of pumped fluid, means operable to anchor the body in said casing in a position of use, means for actuating said anchoring means, packing means expansible to form a fluid tight seal between the body and the casing wall, a hollow mandrel adapted to be connected to and form the lower end of a tubing string by which said device may be lowered into said well casing and through which fluid may be pumped, said mandrel having an axial flow passage and lateral flow ports communicating therewith and being slidably disposed in the bore of said body, and means connecting said mandrel to said body in a normal position aligning its lateral flow ports with the lateral discharge ports of the body, said connecting means being capable of being disabled by an upward pull on the tubing string and mandrel to permit withdrawal of said mandrel from the anchored device.

7. In a device of the character disclosed, the combination of a body having an axial bore and lateral discharge ports communicating therewith, a back-pressure valve normally closing said ports against reverse fluid flow and operable by a predominant internal pressure to an open position permitting outward discharge therethrough of pumped fluid, means operable to anchor the body in said casing in a position of use, means for actuating said anchoring means, packing means expansible to form a fluid tight seal between the body and the casing wall, a hollow mandrel adapted to be connected to and form the lower end of a tubing string by which said device may be lowered into said well casing and through which fluid may be pumped, said mandrel having an axial flow passage and lateral flow ports communicating therewith and being slidablly disposed in the bore of said body, opposed packings disposed above and below said ports in positions to be equally affected by the fluid pressure and form fluid tight seals between said mandrel and the wall of the body bore, and means connecting said mandrel to said body in a normal position aligning its lateral flow ports with the lateral discharge ports of the body, said connecting means being capable of being disabled by an upward pull on the tubing string and mandrel to permit withdrawal of said mandrel from the an chored device.

8. In a device of the character disclosed, the combination of a body having an axial bore and lateral discharge ports communicating therewith, a back-pressure valve normally closing said ports against reverse fluid flow and operable by a predominant internal pressure to an open position permitting outward discharge therethrough of pumped fluid, means operable to anchor the body in said casing in a position of use, means for actuating said anchoring means, packing means expansible to form a fluid tight seal between the body and the casing wall, a hollow mandrel adapted to be connected to and form the lower end of a tubing string by which said device may be lowered into said we l casing and through which fluid may be pumped, said mandrel having an axial flow passage and lateral flow ports communicating therewith and being slidably disposed in the bore of said body, and means connecting said mandrel to said body in a normal position aligning its lateral flow ports with the lateral discharge ports of the body, said connecting means being capable of being disabled by an upward pull on the tubing string and mandrel to permit withdrawal of said mandrel from the anchored device, said body being formed to provide an internal valve seat surrounding the upper portion of the body bore and adapted to be engaged by a valving means sent down the well casing after withdrawal of said tubing string and mandrel from the well casing, said valving means closing the body bore to convert said device into a bridge plug.

9. In a device of the character disclosed, the combination of a body adapted to be lowered into a well casing and through which fluid may be pumped, slip means operable to anchor said body in said well casing, a slip expanding member slidable on said body and carrying an annular packing cup formed of resilient material to provide an inherently expansible longitudinally extended marginal lip, a protective housing enclosing said device and retained thereon by yielding means, said housing normally limiting expansion of said marginal lip and having an inlet opening through which well fluid may flow into said housing during downward travel of said device, and an inlet valve controlling said inlet opening and adapted to be closed by the pumped fluid and cause a building up of pressure within the housing below said packing cup suflicient to overcome said yielding retaining means and force said housing from said device to release said packing lip for engagement with the casing wall and thus condition said packing for axial translation by pressure sub.- sequently built up in the well casing below said packing by the pumped fluid to expand said slip means and form a fluid tight seal between the body and the casing wall.

10. A device of the character disclosed comprising a packer body having a longitudinal flow passage, normally inefiective anchoring means on said body, said anchoring means capable of being rendered effective by fluid pressure, and a fluid conducting setting mandrel removably and slidably projecting into said body flow passage, said body and said mandrel having cooperating flow means through which fluid pressure built up in said mandrel will render said anchoring means effective.

11. A device of the character disclosed comprising a packer body having a longitudinal flow passage, normally ineflective anchoring means on said body, said anchoring means capable of being rendered efiective by fluid pressure, and a fluid conducting setting mandrel removably and slidably projecting into said body flow passage, said body and said mandrel having cooperating flow means through which fluid pressure built up in said mandrel will render said anchoring means effective, and fluid sealing means between said mandrel and the wall of said body flow passage below said cooperating flow means.

12. A device of the character disclosed comprising a packer body adapted to be lowered into a well casing and having a longitudinal flow passage, normally ineffective packing means on said body, said packing means capable of being rendered effective by fluid pressure, and a fluid conducting setting mandrel removably and slidably projecting into said body flow passage, said body and said mandrel having cooperating flow means through which fluid pressure built up in said mandrel will render said packing means effective to form a seal between said body and said well casing.

13. A device of the character disclosed comprising a packer body adapted to be lowered into a well casing and having a longitudinal flow passage, normally ineffective packing means on said body, said packing means capable of being rendered effective by fluid pressure, a fluid conducting setting mandrel removably and slidably projecting into said body flow passage, said body and said mandrel having cooperating flow means through which fluid pressure built up in said mandrel will render said packing means effective to form a seal between said body and said well casing, and fluid sealing means between said mandrel and the wall of said body flow passage below said cooperating flow means.

14. A device of the character disclosed comprising a packer body having a longitudinal flow passage, normally ineffective anchoring means on said body, packing means surrounding said body and capable of being expanded by fluid pressure to actuate said anchoring means, and a fluid conducting setting mandrel removably and slidably projecting into said body flow passage, said body and said mandrel having cooperating flow means through which fluid pressure built up in said mandrel will be effective to expand said packing means and actuate said anchoring means.

15. A device of the character disclosed comprising a packer body having a longitudinal flow passage, normally inefiective' anchoring means on said body, packing means surrounding said body and capable of being expanded by fluid pressure to actuate said anchoring means, a fluid conducting setting mandrel removably and slidably projecting into said body flow passage, said body and said mandrel having cooperating flow means through which fluid pressure built up in said mandrel will be effective to expand said packing means and actuate said anchoring means, and fluid sealing means between said mandrel and the wall of said body flow passage below said cooperating flow means.

16. A device of the character disclosed comprising a packer body having a longitudinal flow passage, normally ineffective anchoring means on said body, said anchoring means capable of being rendered effective by fluid pressure, a fluid conducting setting mandrel removably and slidably projecting into said body flow passage, said body and said mandrel having cooperating flow means through which fluid pressure built up in said mandrel will render said anchoring means effective, fluid sealing means between said mandrel and the wall of said body flow passage on opposite sides of said cooperating flow means, and a back-pressure valve normally closing the flow means of said body.

1'7. A device of the character disclosed comprising a packer body adapted to be lowered into a well casing and having a longitudinal flow passage, normally ineffective packing means on said body, said packing means capable of being rendered effective by fluid pressure, and a fluid conducting setting mandrel removably and slidably projecting into said body flow passage, said body and said mandrel having cooperating flow means through which fluid pressure built up in said mandrel will render said packing means effective to form a seal between said body and said well casing, fluid sealing means between said mandrel and the wall of said body flow passage on opposite sides of said cooperating flow means, and a back-pressure valve normally closing the flow means of said body.

18. A device of the character disclosed comprising a packer body having a longitudinal flow passage, normally ineiiective anchoring means on said body, packing means surrounding said body and capable of being expanded by fluid pressure to actuate said anchoring means, a fluid conducting setting mandrel removably and slidably projecting into said body flow passage, said body and said mandrel having cooperating flow means through which fluid pressur built up in said mandrel will be effective to expand said packing means and actuate said anchoring means, fluid sealing means between said mandrel and the wall of said body flow passage on opposite sides of said cooperating flow means, and a backpressure valve normally closing the flow means of said body.

REUBEN C. BAKER.

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