US2618340A - Well packer - Google Patents

Description

Now/s, 1952 r Zi;

w. E. LYND 2,618,340

WELL PACKER Filed Mayzs. 1947 INVENToR.

Patented Nov. 18, 1952 WELL PACKER William E. Lynd, Corpus Christi, Tex., assignor to Lane-Wells Company, Los Angeles, Calif., a cor-- poration of Delaware Application May 23, 1947, Serial No. 749,927

This invention relates, in general, to wellpackers and more particularly to well packers, bridging plugs and the like devices having means incorporated therein for indicating leakage.

This invention has its most important application to oil wells in which it is desired to carry on; so-called dual production, that is, production from two different formations at separate depths in the well. In such dual production practice it is customary to set a packer between thetwo production zones to isolate them from one `another and then produce the lower zone vthrough the packer and the tubing and the uppernzone through the annular passage between the tubing and the surrounding casing above the packer.

Under. such production conditions it is important for several reasons to determine whether or not there is any leakage of fluid past the packer between the'two producing zones separated by the packer either through the casing ory by channeling outside of the casing. One important reason for this knowledge is to enable one to'fdetermine whether a, zone of higher pressure may be losing production by leakage past the packer or by channeling along the outside of the casing to a zone of lower pressure. When this occurs the current well production rate of the higher pressure zone may not only be reduced but ultimate production thereof may be lost, and irreparable damage also may be done to one formation by contamination with the production fluid from another formation. Also the potential production rate and ultimate production of one such formation may be seriously lowered by loss of gas pressure or other fluid pressure to another formation of relatively low pressure.

Another important reason for accurate determination of whether or not a packer, serving to separate the productions in a well from two different producing zones, is free from leakage, is to enable one to obtain accurate and trulylrepresentative well potential production rates from which proper prorated production rates for the well can be calculated. If a packer in a dual production well should leak, the separate productions from the separate formations will be inuenced by one another. For example, if the packer in a dual production well is leaking and thereby allowing a substantial amount of the uid from one producing zone to now past the packer into the :duid produced from the other zone the apparent potential of the first zone will be less and that of the second zone greater than the true potentials.

Hence it is necessary to maintain the two zones and the productions therefrom isolated, particularly at the time tests are made to establish the true well production rate potentials.

Ordinarily the determination of whether or not there is any such leakage past the packer 16 Claims. (Cl. 166-11) or outside the casing as hereinbefore mentioned' is a very difficult undertaking and at best uncertain.

It is accordingly a primary object of this invention to overcome the hereinbefore mentioned diiculties. v f

It is another object of this invention to pro" vide a means and method for indicating leakage of fluid past a well packer set in a, well.

It is another object of this invention to providev a means and method for determining the occurrence of leakage along the outside of casing set between two or more formations.

It is still another object of this invention to provide a well packer apparatus incorporating automatic leakage indicating means therein.

In general the foregoing objects of this invention are attained by and the invention is embodied in apparatus comprising a packer means for dividing the well casing or borehole into two' longitudinally separated zones, an upper zone and a lower zone, with means incorporated in the packer structure for automatically releasing a tracer fluid upon setting of the packer and occurrence of leakage of the fluid past the packer from one of said zones to the other.

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

In the drawings which show ,by way of illustration preferred embodiments of the invention.

A well casing is shown at C which may be assumed to have been installed in the usual fashion in a well borehole and into which the packer embodying the invention is run.

The packer structure in general, except as described hereinafter, may be similar to that shown and described in the U. S. Patent 2,005,955 and comprises the following parts:

A packer head or top collar member I0, carries..

through a threaded joint II, a hollow mandrel tube or body I2 which mandrel tube extends downward and concentrically through the packer and slip assemblies. The packer head Il) is adapted to make threaded coupling at I3 with suitable drill pipe or tubing I4 by means of which l the whole packer apparatus is suspended while.

being lowered through the well casing and by means of which the packer is manipulated and downward force is applied to set the packer and expand the resilient packing elements into sealing engagement within a surrounding casing after the packer is set. The drill pipe or tubing I4 also serves, after the packer is set, to convey to the well surface any fluid produced from the well below the packer, as hereinafter more fully described.

Concentrically surrounding the mandrel I2 and slidably spaced therefrom are a pair of longitudinally spaced packing assemblies the upper packing assembly being shown at P1 and the lower packing assembly being shown at Pz.

The upper packing assembly P1 comprises a packing supporting sleeve I6a threadedly connected at its upper end to an annular valve seat member I1. The lower portion of the packing supporting sleeve Ilia extends downward slidably -through a packing retaining nut which in turn makes threaded connection at 2| with the upper end of an intermediate cylindrical spacer body 23. The lower end of the packing supporting sleeve ISa carries a downwardly extending cylindrical or ring shaped nut threadedly connected thereto at 26.

A resilient packing element or sleeve, or a plurality of resilient packing rings 21 encircle the supporting sleeve I6a, are retained in position thereon, and are adapted to be axially compressed between the packing setting means which includes the inner confronting annular surfaces of the beforementioned valve seat member I1 and the retaining nut 20.

The lower end portion of the intermediate. cylindrical, spacer -body 23 has a form similar to that of the hereinbefore described valve seat member I1 and makes threaded connection as shown at 28 with the upper end of a lower packing supporting sleeve I6b. The lower portion of the lower packing supporting sleeve I6b extends downwardly slidably through a lower packing retaining nut 29 which in turn makes threaded connection 30 with the upper end of a slip cone body 3|. The lower end of the packing retaining sleeve I6b instead of carrying a cylindrical nut, as shown at 25, on the upper packing retaining sleeves IGa, is formed with an offset, outwardly extending shoulder as shown at 32 which when the packer is in an unset condition normally acts as a stop to limit the longitudinal sliding motion of the sleeve |6b with respect to the beforementioned packing retainer nut 29.

A resilient packing element or sleeve or a plurality of resilient packing rings as shown at 33 encircle the lower packing supporting sleeve I6b, are retained in position thereon, and are adapted to be axially compressed between the packing setting means which includes the inner confronting annular surfaces of the beforementioned lower end of the intermediate cylindrical spacer body 23 and the lower retaining nut 29.

The beforementioned intermediate cylindrical spacer body 23 is formed with an inner, upwardly facing. annular recess as shown at 35 in coaxial alignment with the beforementioned ring nut 25. A plurality of radially directed ducts or ports 36 interconnect the bottom of the recess 35 and the exterior of the spacer body 23 intermediate the packer assemblies P1 and P2. A suitable annular or ring shaped packing member 31 makes a slidable but fluid-tight press iit into the upper portion of the beforementioned annular slot 35.

The nnular slot 35 below the annular packing member 31 is adapted to retain a suitable capsule or the like container or a number of capsules as shown at 38, containing a tracer material, as hereinafter more fully described.

Means are provided for anchoring the beforementioned slip cone 3| to the casing in a more or less conventional manner. Such means comprise slips 40 which are slidably mounted in dovetail slip guides 4| formed in the said slip cone 3|, the said slips being restrained from movement outwardly from the cone by the overhanging walls of the dove-tail guides but being free to slide longitudinally along the slip surfaces.

The slip control mechanism includes a slip cage of more or less conventional design comprising a plurality of outwardly bowed cage friction springs 42 which are rigidly attached at their lower ends to the lower end portion of a cage sleeve 43 and at their upper ends to a ring or collar 44 which is slidable longitudinally on the upper portion of the said sleeve 43 to permit lateral contraction and expansion of the bow springs 42.

The cage sleeve 43 is free to rotate and slide longitudinally upon the mandrel I2 except as limited by a dowel or latch pin 45 which projects outwardly from the mandrel into slidable engagement within a J-slot 46 formed in the cage sleeve and having a vertical portion 41 and a recessed, lateral portion as shown at 48.

A slip rein ring or collar 50 is retained on the upper end portion of the slip cage sleeve 43 in an annular groove, as shown at 5|, providing freedom for rotational movement but preventing lateral movement thereof with respect to the sleeve. A plurality of slip reins 52 interlink the collar 50 and the slips 40; one rein for each slip. In operation the slips 4|] are set and released in response to vertical movement of the cage sleeve 43 relative to the slip cone 3| as hereinafter more fully described in connection with the operation of the device.

The operation of the apparatus of the invention is as follows:

The packer apparatus is lowered through the well casing in the condition shown in Figure 1 to the level in the well or opposite the formation at which it is desired to be set. When the packer apparatus has been thus lowered to the setting position the latch pin 45 is released from the lateral recess 48 of the J-slot 46 in the slip cage sleeve 43 by imparting slight left-hand rotational f movement to the mandrel I2 through the supporting tubing I4. Relative rotation is thus imparted between the latch-pin 45 and the cage sleeve 43 by reason of the fact that the cage sleeve 43 is restrained against rotation by the frictonal engagement of the cage springs 52 with the inside surface of the casing C, whereas the mandrel I2 is free to rotate `with the string of tubing I4 to which it is attached.

After the latchpin 45 has been thus released from the J-slot recess 48 the tubing is again lowered a short distance resulting in downward movement of the mandrel I2 with respect to the cage sleeve 43. Due to the frictional engagement of the cage springs 42 with the inside surface of the casing C the sleeve 43 remains substantially stationary. The whole packer mechanism including packing assemblies P1 and Pz will then be free to move downward with the mandrel I2, the whole assembly thereof initially riding upon and being supported by the shoulder 55 provided in the lower portion of the mandrel. The sleeve 43, slip collar 50, slip reins 52,

infima-ai and slips 40 will thus be caused, in effect, to move upward relative to the downwardly moving packer assembly including the slip cone 3|, and the slips 40 will thus be caused to move upward along the slip cone guides and outward into gripping engagement with the inside surface of the casing thereby locking the cone 3| to the casing and preventing any further downward movement thereof relative to the casing. Thereafter, further downward movement of the mandrel I2 is continued while the packing assemblies P1 and Pz remain stationary, supported upon the slip cone 3|, until the valve face 56 of the head l0 comes to restupon the valve seat 51 in the upper end of the valve s-eat member |1 which seals the circulation passage through the packer between the mandrel I2 and the packing supporting sleeves |60, and I6b. Further downward movement of the tubing string thereafter forces the upper valve seat I1 and packing retainer sleeve |6a downward with respect to the packing retaining nut thereby applying longitudinal compressive force and motion to the resilient packing sleeve or rings 21. This longitudinal or axial force i-s in turn transmitted through the packing retainer nut 20 and the intermediate cylindrical spacer body 23 to the lower packing sleeve or rings 33 resulting in downward motion of the said intermediate cylindrical spacer body 23 and the lower packing retainer sleeve |6b relative to the before-mentioned packing'retainer nut 29 and slip cones 3| and thereby applying longitudinal compressive force to the resilient packing sleeve or rings 33.

' Downward motion and pressure is continued to be applied through tubing I4 until the packer is firmly seated and set with the packings 21 and 33 expanded into sealing engagement with the inside 'surface of the casing C as illustrated in Figure 2.

As the upper packing retainer sleeve |6a moves downward, with respect to the upper packing retainer nut 20 during the setting operation. and as the packing rings 21 are compressed longitudinally the depending portion of the cylindrical nut member 25 carried on thelower end of the sleeve |6a moves downward into the upper open end portion of the annular groove and into contact with the upper surface of the annular packing member 31. The packing elements 21 in the upper packing assembly P1 and the relative length of the sleeve |6a and intermediate cylindrical spacer body 23 are so proportioned that when the packer is fully set in a given casing or borehole, as illustrated in Figure 2, the

cylindrical nut member 25 is moved downward'j'f a sum-cient distance to be brought into contact' with the annular packing member 31 and to move the packing member 31 downward against the frangible capsule 38 and apply sufficient pressure to said capsule 38 to crush or rupture it and release the tracer material contained within it. Upon thus breaking the frangible capsule 38 and releasing the tracer material into the lower end porti-on of the recess 35 the tracer material is thenfree to flow or move or be expelled outward through the ducts 36 into the annular space or cavity formed between the concentrically positioned outside surface of the intermediate cylindrical spacer body 23 and the inside surface of the casing C and between the sealed off upper and lower inner ends by the packing assemblies P1 and P2.

After the packer has been set as hereinbefore described andis in the position illustrated in Figure 2, and the tracer iiuid has been released, to the annular space 60, any leakage of fluidin.

either direction past the packing assemblies P1 and Pz betweenr the upper land lower portions of the well casing above and below the packer mechanism will resu'lt in carrying a portion of the tracerl material from the annular space 60 along with the leakage fluid. The tracer materialwill thus eventually appear in the well,

fluid produced from the well either through the well tubing I4 or through the annular space 6| intermediate the well casing C and the tubing I4.

For example, if the pressure in the casing C is greater above the packer than it is below the packer there is a downward diierential pressure across the packing elements P1 and P2 and if under these conditions there is any substantial leakage past the packing elements P1 and Pz the tracer fluid which has been released into the annular space 60 will be carried downward into the annular space below the packer and between the mandrel l2 and the casing C. The tracer ui-d will then be carried downward through the lower annulus and if the well is being produced through the tubing will eventually enter the tubing at its lower end and ilo-w together with the production through the tubing to the well surfacev where it may be detected b y suitable means.

If, on the other hand, the differential pressure pa-st the vpacking elements P1 and P2 is upward andv leakage occurs, th-e tracer iiuid contained in the annular cavity 60 will be carried upward past the packer into the annular space 6| between the tubing I4 and the casing C and production of fluid from the well through the annulus will thereby carry the trace;` material along with it to the well surface where the presence of the tracer material may, as beforementioned, be detected there by suitable means.

The frangible container for the tracer material may be in th-e form of a hollow or tubular annular ring made of glass and adapted to fit into the recess 35, or the tracer material may be contained in a plurality of hollow, spherical or slightly lelongated glass capsules. The annular hollowrfring or the plurality of hollow capsulesv may also be made of a suitable plastic material, in either case the material being such that it will be/fractured or ruptured upon application of crushing force lbeneath the annular packing ring 31 to liberate the tracer material into ducts 36. A typical example of the testing procedure emf ployed in connection with the use of the apparatus of the invention hereinbefore described is as follows:

In a cased well 9000 feet deep with a producing sand of gas distillate at 7,500 feet the bottom hole pressure is approximately 3,800 pounds. Also at 8,950 feet a sand exists, producing oil with a iiuid pressure at that point of 3,000 pounds per square inch. It is desired to produce the top sands through the casing and the lower sands through the tubing. The casing is perforated at approximately 7,500 feet and at approximately 8,950 feet respectively, opposite the upper and lower producing formations. 1400 feet of tubing is rst run into the hole and the packer device hereinbefore described, containing the tracer iiuid is installed at its top end. The packer carrying the 1,400 foot length of tubing depending therefrom is then run into the well on a suitable tubing string and set about 10 feet below the top perforations. Connections are then installed at the casing head with provisions for separately controlling and separately collecting the ilow from the tubing and the casing. The lower zone is then flowed through the tubing and the upper zone through the annulus between the casing and tubing. Under such conditions if a leak occurs it is usually past the packer between packing and casing or through the leaks in the tubing Walls or joints or through channeling in the cement along the outside of the casing.

After the well flow is thus established one or other of the formations may be rst shut in; for example the upper producing zone is rst shut in and the production from the bottom producing zone allowed to flow through the tubing at as high a rate as possible. Since flowing of the production through the tubing at a high rate will materially decrease the well pressure at the bottom of the well below the packer the differential pressure downward across the packings will then be a maximum. If the packing leaks under this condition the tracer fluid will be carried into the lower portion of the casing below the packer and be produced through the tubing along with the lower zone production. If no tracer fluid is produced through the tubing the packer is obviously holding under this condition without leakage. Next the tubing should be shut in and the production from the upper producing zone allowed to flow through the casing annulus at as high a rate as possible. Under this condition the differential pressure upward across the packings will be a maximum. If the packer leaks under this condition the tracer fluid will be carried into the upper portion of the casing above the packer and be produced through the casing annulus along with the upper zone production. If no tracer fluid appears in the production through the casing annulus the packer is obviously holding without leakage.

Now if in the first test hereinbefore mentioned, tracer fluid is produced but in the second test no tracer uid is produced this would be an indication of failure of the lower packing element of the packer, allowing some of the tracer fluid to leak down and be produced through the tubing. However, the fact that no tracer fluid is produced through the casing annulus production, means that the upper packing element is still intact and functioning properly. The inverse of this would be true if the casing production contained tracer fluid butthe tubing production contained none, that is, it would indicate that the lower packing element is intact but that the upper packing element of that packer had failed and was leaking:

In a perfect packoff, no tracer fluid would be produced at any time either through the-tubing or the casing.

If, however, no tracer fluid is produced eitherl through the tubing or casing but the tubing and casing pressure substantially equalize when both casing and tubing are shut-in it is obvious that a leak exists somewhere else. In this latter case the leak may be either through defects in the tubing or possibly the leakage is occurring by channeling through or around the cement outside of the casing between the upper and the lower producing zones, and measures may then be taken to check the condition of the tubing and if necessary also to perform squeeze cementing in the manner well known in the art to eliminate' any channeling leakage.

While a circulation type of casing packer mechanism is shown and described herein as a preferred apparatus to which the present invention is applicable, it is not so limited since the present invention is applicable to advantage to any type of packer which operates in a manner similar to that herein illustrated to place, expand or deform a resilient packing element or body radially into sealing engagement with a surrounding casing or formation wall.

The process and apparatus of this invention is, furthermore, not limited in its applicationK to production type packers as herein illustrated but is also applicable to various other types of packers such as packers similarly constructed and adapted to be set in direct engagement with well borehole formations or in connection with bridging plugs adapted to be set either in casing or in uncased bores.

The tracer material may be any one or a mixture of two or more of the well known dyes which have been similarly employed to trace the ow or course of fluids such as, for example, flu es ein, uranine, egsminnngvemnptisin and thewlike.

When uores'ceirimis eplyed as the tracer material its prese in the production from the well may be detected by drawing samples of the produced liquid and allowing it to stand quiescent in an open container for a relative short period of time. If the produced liquid is mainly oil the fluorescein, being relatively insoluble in oil and lighter than oil will float to the top surface and appear there upon inspection as a thin surface lm or blotch, or as thin thread like or straited discolorations on the surface when the sample is stirred gently. If the produced liquid is water. or is oil containing suflicient water to separate therefrom by gravity, the presence of fluorescein therein can be detected by the characteristic greenish-yellow color which it imparts to the settled-out water phase.

If uranine dye is employed as the tracer material either in a liquid solution or in dry powdered form, its presence will be indicated by the yellowish color it imparts to the water phase.

While the term tracer material has been used frequently herein it is to be understood that this is intended to include not only solid materials but also suitable liquid and gaseous tracers. In the case where iluorescein, uranine or eosin and the like dyes are employed as the tracer materials they may be utilized either in concentrated solutions in suitable liquids in which they nare soluble, or in suspension in suitable liquid dispersing agents or in dry crystalline powder form.

In the latter event where powdered tracer material is employed it reaches the annular space 60 from the recess 35 by diffusion through the leakage fluid, if any, which enters these spaces by leakage past the packing elements. f-

It is to be understood that the foregoing is illustrative of but one method and apparatus and that the invention is not limited thereby,but may include various modifications and changes made by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In a dual production method wherein a packer is set on a string of tubing in a well intermediate upper and'lower producing zones to isolate said zones from one another and one of said zones is produced through the tubing and the other is produced through the annular space in the well outside of the said tubing the method of detecting leakage past said packer between said zones comprising the steps of releasing a tracer material into contact with the said well wall at a point longitudinally intermediate'the upper and lower ends of said packer; shutting in one of said zones and while so shut in producing the other zone and testing the production so produced to determine the presence of any tracer material therein.

2. In a dual production method wherein a packer is set onA a string of tubing in a well intermediate upper and lower producing zones to isolate said zones from one another and one of said zones is produced through the tubing and the other is produced through the annular space in the well outside of the said tubing the method of detecting leakage past said packer between said zones comprising the steps of releasing a tracer material into contact with the said well wall at a point longitudinally intermediate the upper and lower ends of said packer; shutting in one of said zones and while so shut-in producing the other zone and testing the production so produced to determine the presence of any tracer material therein; then shutting in the said other zone so produced and producing the said one of said zones previously shut-in and testing the production so produced to determine the presence of any tracer material therein.

3. In a dual production method wherein a packer is set on a string of tubing in a well intermediate upper and lower producing zones to isolate said zones from one another and one of said zones is produced through the tubing and the other is produced through the annular space in the well outside of the said tubing the method of .detecting leakage past said packer between said zones comprising the steps of releasing a tracer material into contact with the said well wall at a point longitudinally intermediate the upper and lower ends of said packer; shutting in one of said zones and while so shut-in producing the other zone and testing the production so produced to determine the presence of any tracer material therein; then shutting in the said other zone so produced and producing the said one of said zones previously shut-in and testing the production so produced to determine the presence of any tracer material therein and then simultaneously shutting in both of said zones to compare the shut-in pressures of said zones.

4. In a dual production method wherein a packer is set on a string of tubing in a well intermediate upper and lower producing zones to isolate said zones from one another and one of said zones is produced through the tubing and the other is produced through the annular space in the Well outside of the said tubing the method of detecting leakage past said packer between said zones comprising the steps of releasing a tracer material into contact with the said Well wall at a point longitudinally intermediate the upper and lower ends of said packer; then simultaneously shutting in both of said zones to compare the shut-in pressures of said zones; then produc- ,ing one of said zones while the other of said zones is shut-in and testing the production so produced to determine the presence of any tracer material thereinjthen shutting in the said one of said zones so produced and producing the other of said zones previously shut-in and testing the production so produced to determine the presence of any the well outside of the said tubing the method of detecting leakage past said packer between said zones comprising the steps of releasing a tracer material into contact with the said Well wall at a point longitudinally intermediate the upper and lower ends of said packer; shutting in one of said zones and while so shut-in producing the other zone and testing the production so produced-to determine the presence of any tracer material therein; then simultaneously shutting in both of said zones to compare the shut-inpressures of said zones; then producing said one of said zones previously shut-in while said other zone is shut in and testing the production so produced to determine the presence of any tracer material therein.

6. Packer apparatus comprising: a pair of interconnected packing assemblies having a pair of spaced packing elements; setting means in said assemblies movable longitudinally relative to one another to expand said packing elements laterally into sealing engagement with a surrounding borehole wall; a member of said; assemblies having formed in it a. chamber adapted to contain tracer material; a duct leading through a wall of said member from said chamber to a point on the exterior of the packer apparatus intermediate said packing elements; and means coupled to at least one of said setting means and movable thereby relative .to said chamber to expel tracer material from said chamber through said duct to the space intermediate said packing elements.

7. Packer apparatus comprising: a packer body; a pair of longitudinally spaced packing elements surrounding said packer body; a pair of setting means on said packer bodyv and movable with respect to one another to expand said packing elements into sealing engagement between said packer body and a surrounding borehole wall to form thereby a sealed-oft` cavity between said packing elements and between said packer body and said wall; a frangible container positioned intermediate relatively movable portions of said pair of setting means and in communication with said sealed-off cavity; and

means coupled to said pair of setting means andv movable thereby into contact with said frangible container upon imparting relative motion between said pair of setting means, to rupture said container and release a tracer material from said container into said sealed-off cavity.

8. Packer apparatus comprising: a packer body; a pair of longitudinally spaced packing elements surrounding said packer body; a member carried by said packer body having walls defining a chamber therein and adapted to contain a quantity of a tracer material; a pair of setting means on said packer body and movable with respect to one another to place said packing ele- .ments into sealing engagement between said packer body and a surrounding borehole Wall to form thereby a sealed-off cavity between said packing elements and between said packer body and said wall; a flow passageway providing communication between said chamber and said cavity and means coupled to said pair of setting means and actuatable by movement thereof relative to one another to apply pressure to such tracer ma- Iterial in said chamber and thereby eiect expulsion of said tracer material from said chamber through said flow passageway into said sealedoi cavity.

9. Packer V apparatus comprising: a packer body; a pair of longitudinally spaced packing elements surrounding said packer body; a memlber in saidpacker body having walls defining a chamber therein and adapted to contain a tracer material-containing capsule; a pair of setting means on said packer body and movable relative to one another to place said packing elements into sealing engagement between said packer body and a surrounding borehole wall to form thereby a sealed-oir cavity between said packing elements and between said packer body and said wallpa duct in said member interconnecting said chamber and said'cavity; and means coupled to Vand, actuatable by the movement of said setting means relative to one another to apply a rupturing pressure to such capsule in said chamber and thereby eiiect the release of tracer material from such capsule'into said chamber from which it may flow through said duct to said sealed-oil cavity.

10. Packer apparatus comprising: a packer body; a .pair of longitudinally spaced packing elements surrounding said packer body; a pair of setting means on said packer body and movable relative to one another to place said packing elements into sealing engagement between said packer body and a surrounding borehole wall to form thereby a sealed-oir cavitybetween said packing elements and between said packer body and said Wall; a frangible tracer container carried by said packer body, the exterior of said container -being positioned in communication with said sealed-0E cavity; and means coupled'to and actuatable by movement of said setting means relative to 'one another, to apply a rupturing force to said frangible container and thereby release tracer material therefrom into said sealed-ofi' cavity.-

11. Packer apparatus comprising: a packer body;a pair of .longitudinally spaced packing elements surrounding said packer body; a member carried by said packer body having walls dening a chamber; a pair of setting means on said body movable relative to one another to place said packing elements into sealing engagement between said packer body and a surrounding borehole wall to form thereby a sealed-off cavity between said packing elements and between said packer body and said wall; a frangible tracer material-containing means in said chamber; a flow passageway extending from said chamber to the exterior of said packer body through which said chamber and `said sealed-off cavityl are interconnected; and means coupled to and actuatable by movement of said pair of said setting means relative to one another to apply a rupturing force to said frang'ible containing means and thereby release tracer material therefrom into said chamber for passage through said ow passageway into said sealed-oil` cavity when said packer is set.

12.-Packer apparatus comprising: a r packer body adapted to be secured to the lower end of a tubing-string; a pair of longitudinally spaced packing elements surrounding said packer body; a pair of setting elements on said packer body movable relative to one another to expand said packing elements into sealing engagement with the inside surface of a surrounding casing and thereby form a sealed-oit, annular space intermediate said packing elements and between said packer body and said casing; a normally fluidtight initially closed container in said apparatus to contain a quantity of a-tracer material, the exterior of said container being positioned in communication with said annularspacef and means coupled to and movable by said pair or setting elements to apply compressiveforce to said closed container suicient to open said con tainer into said sealed-01T, annularA space.

13. Packer apparatus comprising: a packer assembly including packing means adapted to be moved into sealing engagement with a surrounding wall; actuating means in said apparatus movable relative to said packing means for moving said packing meansinto sealing engagement with said wall; a container for a tracer material in said packer assembly; and means coupled with said actuating means, for releasing ltracer material from said container to a point exterior to said packing means adjacent said wall and longitudinally intermediate the ends of said packing means when said packing means is moved into sealing engagement with said wall.

14. Packer apparatus comprising: a mandrel adapted to be secured to the lower end of a tubing string; a pair of longitudinally spaced, coaxial sleeve elements slidably supported with respect to one another on said mandrel; a packing element on each of said sleeve elements; means carried by said sleeve elements to compress said packing elements axially and thereby expand said packing elements radially into sealing engagement with a. surrounding casing when said sleeve elements are moved axially toward o'ne another on said mandrel; a chamber carried by one of said sleeve elements; a projection carried by the other of said sleeve elements positioned to enter said chamber when said 4sleeve elements are moved axially toward one another suiciently to expand said packing elements into sealing engagement with said casing; anda flow'passageway extending from the interior of said chamber through the said one sleeve element to a point on the exterior of the sleeve element adjacent the inner adjacent ends of said spaced packing elements.

15. Packer apparatus according to claim 14 with a fluid-tight container in said chamber in position to be ruptured by the entranceof said projection into said chamber to release and to expel material from said container through said ow passageway when said projection enters said chamber.

16. Packer apparatus according -t'd'claim 14 With a frangible fluid-tight container' "-i'n` said chamber in position to be ruptured by 'said projection to release and to expel materialfrom said container and from said chamber through said iiow passageway when said projection enters said chamber.

WILLIAM E. LYND.

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

UNITED STATES PATENTS Ferguson Dec. 8, 1942

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