US2942668A - Well plugging, packing, and/or testing tool - Google Patents

Description

June 28, 1960 G. P. MALY ETAL WELL PLUGGING, PACKING AND/OR TESTING TOOL Filed NOV. 19, 1957 llllllllf'l I .lllll'l 1 fiz'azaz fan 4n: A Puma United States Paten F WELL PLUGGING, PACKING, AND/ OR TESTING TOOL George P. Maly and Edward A. Pullen, Fullerton, Calif., assignors to Union Oil Company of California, Los Angeles, Calif.,a corporation of California Filed Nov. 19, 1957, Ser. No. 697,350

19 Claims. (Cl. 166-187) This invention relates to a well tool, and in particular concerns a device adapted to be inserted in a well bore for the purpose of dividing the bore laterally into two or more portions. In accordance with the invention, the principle thereof is embodied in the form of simple plugging or packing tools, or in devices for sampling well fluids and/ or determining their nature and the conditions under which they exist within the subterranean strata traversed by the well bore.

The use of packers or plugs in well bores in connection with such operations as cementing, repressuring, testing, etc., is well known, and a great variety of such tools has been proposed. All of such devices, however, comprise one or more sealing elements which are capable of being inserted into the well bore and expanded radially therein until they meet the walls of the bore or the well casing and engage the same in fluid-tight relationship. Such packing elements have been actuated by mechanical or hydraulic means controlled from the earths surface.

It is an object of the present invention to'provide a well tool comprising a sealing element which is actuated by pressure developed within the well bore. Another object is to provide a'device of such character in which the actuating pressure is generated immediately adja cent the sealing element itself. A further object is to provide such a device in which the actuating pressure is that developedby a material when it undergoes a change in phase from the solid to the liquid state. Other and related objects will be apparent from the following detailed description of the invention, and various advantages not specifically referred to herein will be apparent to those skilled in the art upon' employment of the invention in practice.

In the drawings which form a part of this application:

Figure 1 is a longitudinal sectional view of-a simple embodiment of the invention illustrating the principle thereof.

Figure 2 is a longitudinal sectional view of the device of Figure 1 after expansion of the sealing element thereof.

Figure 3 is a longitudinal sectional view of another embodiment of the invention in which multiple sealing elements are provided.

Figure 4 is a longitudinal sectional view of a well tool embodying the principle of the invention and comprising a plurality of spaced sealing elements which serve to'di vide a selected length of a well bore into a plurality of isolated portions.

Figure 5 is a longitudinal sectional view of a modification of the device of Figure 4.

Figure 6 is a longitudinal sectional view of a well-fluid testing device embodying the principle of the invention;

Referring now to Figures 1 and 2, in which like numerals designate like parts, the device there shown is a packer for closing oil the annulus between a well casing and tubing. Said packer consists of a mandrel or conduit 10 which constitutes the body portion of the device. Said body portion is provided with screw threads at its 2,942,668 Patented June 28, 1960 upper end, whereby it maybe attached to and made a part of the well tubing string. Upper and lower retaining plates 11 and 12, respectively, are rigidly affixed to conduit 10 in parallel spaced relationship, and have outside diameters smaller than the inside diameter of well casing 13 in which the device'is to be employed. Annular sealing ring 14 normally having an outside diameter smaller than the inside diameter of well casing 13 and an inside diameter considerably larger than the outside diameter of 'conduit'lll but smaller than the outside diameter of plates 11 and 12, is held between'plates 11 and 12 in sliding engagement with the opposed faces thereof. Sealing ring 14 is constructed of a resilient expansible material which is not attacked by the well fluids, and may suitably be a hydrocarbon-resistant synthetic rubber such as Thiokol'or neoprene. By reason of the difference in the diameters of conduit 10, retaining plates 11 and I2, and sealing ring 14, the device comprises an enclosed annular chamber, the lateral surfaces of which are defined by the opposed faces of plates 11 and 12 and the longitudinal surfaces of which are'defined by the outer'surface of conduit 10 and the inner surface of sealing ring 14. Said annular chamber is substantially completely filled with a body 15a of a material which changes from a solid to a liquid with an increase in volume at a temperature between that of the atmosphere at the earths surface and that which exists within the well bore at the 'point where the device is to be employed.

Operation of the device'of Figures 1 and 2 is as follows: The assembly is coupled to the well tubing by means of the screw threads on conduit 10 and is'lowered into the Well casing to the desired level. Inasmuch as the body of a meltable material 15a has a melting point below that which exists at such level, upon the attainment of equilibrium temperature'conditions body 15a will melt to form a body'of liquid (15b in Figure 2) of increased volume. The force of the expansion is directed radially andoutwardly' a'gainst'the inner surface of sealing ring 14, and the latter, being resilient and expansible, is thus forced outwardly against casing 13 to form a fluid-tight seal therewith as shown in Figure 2. Referring now to Figure 3, the device'there shown is a plugging tool which'issimilar in purpose and construction to that of Figures 1 and 2, except that two sealing rings are provided in order to cope with higher pressure dilferentials across the tool. Said device consists of a body member 20 having three retaining plates 21, 22 and 23 rigidly aflixed thereto. Upper and lower sealing rings 24 and 25, respectively, are held between the opposed faces of retaining plates Hand 22 and 22 and 23, respectively. Upper-and lower bodies of meltable material 26 and 27, respectively, substantially'fill the two annular closed spaces defined by the sealing rings, the retaining plates and the conduit. 'The operation of the device is exactly like that of the device of Figures 1 and 2.

We are aware that it has been proposed to construct packing and plugging tools in which a resilient sealing element is forced outwardly against the'well casing by means of a fluid which is forced down the well tubing or other conduit under pressure. The devices of the present invention, however, operate under an entirely different principle in that the pressure which forces the sealing element outwardly against the well casing is developed, not by a pump at the earths surface and trans: mitted to the device via a column of fluid, or even by the hydrostatic head of a column of liquid, but rather by a body of material undergoing the increase in volume which accompanies a change from the solid to the liquid state. The pressures generated during such change in state are known to be remarkably high, but insofar as we are aware they have not heretofore been employed for actu 7 cent.

The meltable material employed in the devices of the invention is preferably a hydrocarbon wax, i.e., a solid paraffin, but may beany material which increases in volume upon changing from the solid-'to the'liquid state. As 1 previously. stated, such change of state should occur ata temperature above that of the atmosphere at the well head but below that which prevails at the'point within the well bore where the sealing element is to be actuated. Such temperature is ordinarily between about 75 and about 300 F, Thehydrocarbon waxes are preferred by reason of their low cost,

their inertness with respect to materials of construction 1 and, in particular, by'reason ofthe factthat they undergo, a relatively large volume: change upon melting and can be blended to have substantially any desired melting point within the stated temperature range. Since it is usually desirable that thewax have a fairly sharp melting point, relatively highly refined de-oiled waxes are especially preferred, particularly those which melt fairly sharply in'the range 140-200 F. The increase in volume upon melting is of importance in that it deter mines the dimensions of the device; Thus, in the device ofFigure 1, if the body of meltable material a is, of such nature that the increase in volume upon melting is, say, 5 percent, the outside diameter of sealing ring 14 7' will have to be more nearly equal to the inside diameter of casing 13 than if such volume increase is,'say, 20 per- 7 However, this is because, in the latter instance, sealing ring 14 will be expanded a greater radial'distance than because of anysubstantial difference in the pressure developed. As a practical matter, we prefer to employ a hydrocarbonwax which undergoes a volume increas of atleast about 10 percent. 1

In addition to the preferred hydrocarbon waxes, the body'of meltable'material may alsobecomposed of a metal or metal alloy having the appropriate melting point and also having the property of expanding on melting. Certain alloys of bismuth possess these properties. In addition, reference to any dictionary of. chemical com will. disclose'numerous organiccompounds which fulfill sampling device of Figure 4, the tool is-inserted into the well bore on the end of the tubing string, and is positioned within the bore so as to span the strata whose effluents are to be sampled. If the well in flowing, superimposed pressure may be applied to the casing to prevent well fluids from entering the same while the tool is being placed in positionfAltrnatively, an inert gas may be forced down the well tubing under sufiicient pressure to prevent well fluids from entering the tool during its positioning. The tool ,isthen se by holding it in place untilpthebodiesof paraflin wax melt by reason of the ambient temperaturebeing abovetheir melting point. Such melting is accompanied by an increase in volume, and the pressure developed thereby is directed radially against the sealing rings, whereby the latter expand outwardly to form fluid-tight seals with the well casing.

enter perforations 53.v When equilibrium conditions have been established, the tool is withdrawn from the well bore. The contents ,of each of the chambers are representative of the efiluent from each of the strataspanned by each of said chambers. :From the'dimensions of the tool, i.e., the length of each of the cylindrical shells and the known depth at which the tool waslpositionedpthe depth and thickness of the variousstrata investigated are known, and examination of the contents of each chamber provides information: as. to. the nature and amount of the fluids eflluent from each of said strata. As is apparent, the device-may be constructed so as ,to, have any numberof chambers extending between adjacent sealing rings j. held between adjacent retainingp lates constituting. a pair.

the requirements, and any of such compounds may be V employed.

Referring now to Figure 4,'which illustrates another embodiment of the invention in -the'form of avsimple well-fluid sampling tool, the device there shown comprisesa conduit 40 provided with screw threads at its 1 upper end, whereby it maybe attached to. the well tubing.

Retaining plates 41'.46 are rigidly afiixed, as by weld- Thedevice'efQPigure4 may also ,be employed as a plugging tool toinject a plugging agent iritp a particular stratum or. strata traversed. by the-well b I In accordance withsuclr use, the device is employe above described to determine the location of-thoselstrata from which undesirable well fluids, e. g., water,; flow into the well bore.. Those portions of the tool .-v vhichwer e found to span a stratumorstrata producingidesired well fluids are. then plugged off as by inserting plugsin. perforations 47;: and/or its, counterparts The tool-is then rein- Serted n. t w e e n i p e iq Po tio whe eby only those portions of the tool which span the sources of undesirable fiuids are placed i i communication with cgnduit Ai it b e l n ents- 1 ggmentor V a iqu d a le f m n a id ponl 1 se 9 nection with Figures 1-3, and each of the enclosed an- .nular spaces defined by conduit 40 and each pair of retaining plates and each sealing ring is filled with a body 49a,- 49b, and 490 of a normally solid material of suitable melting point, e.g., paraflin wax having a melting point time, is pumped down conduit '40, through perforations 47 a, 53 and 55, and into the strata wherein said agent solidifies to form a plug. 7 The tool -is then withdrawn from the bore, wherebyonly those strata which produce desirable well fluids are placed 7 in communication with the bore, 7

between,l40' and 160 F.- The upper retaining plate paraflin' wax 49e-.-49c are introduced during assembly of the device, said filler holes being normally closed by with-lateral perforations 53,- extend between the opposed faces of adjacent pairs of retaining plates and engage the same in fluid-tight relationship: The-dimensions of the device are such that it is normally capable of being -in V of each pair,i.e., retaining plates 41,43 and 45, is provided Wlth'fl filler hole through which the bodies of I plugs 56a'56c. Cylindrical shells SO and'51, provided serted into. well casing 54 which has been perforated V asat55. l V ..In. accordance with one method-'- or employing the Referring now to Figure 5, there isishown a modifica tion of the sampling tool described above-in connection Figure 4. Those parts which the devices of Figures 4 -and 5 have in common are designated by like numerals. i The device, comprises a central conduit 40 having retaining plates 41, 42, 43, 44, and '45; rigidly affixed thereto in spacedpairs. Sealing rings 48a, 48b and 480 are held between each pair, of retaining plates, and each of the annular spaces formed byeach pair of retaining plates and'the sealing ring associated therewith is substantially filled with a body 49a, 49b and 4900f a material such as paraflin wax. The tool is shown positioned within well casing .54. in set condition, i.e., the bodiesmof wax;49a and 4% are shown in molten form with sealing- rings 48 a,48c expanded to form fluid-tight seals with casing 54. 1 The latter is'perforatedas at- 55.

Cylindrical shells 50a and 51a extend between adjacent pairs of retaining plates, thereby forming a series of closed chambers 57a and 57b. Within chamber 57a a conduit 58 communicates between the exterior of the tool and the interior of conduit 40, and a solenoid-operated valve 59 is interposed in conduit 58. Valve 59 is operated by an electric current supplied thereto from the earths surface via an electrical conductor 60 which passes through the wall of conduit 40 via. seal 64. By suitably operating valve 59 the well effiuents which pass through perforations 55 can be diverted into chamber 57a through valve port 61. In employing the device of Figure 5 to obtain samples of the strata spanned by chamber 57a, the device is lowered into the well bore with valve 59 in closed position. When sealing rings 48a and 48b are set by the melting and accompanying expansion of the bodies of paraflin wax 49a and 49b, valve 59 is opened to allow said well fluids to enter chamber 57a via perforations 55, conduit 58,. valve 59, and port 61. When equilibrium conditions are attained, valve 59 is closed and the tool is withdrawn from the well bore.

Figure 5 also shows a modification whereby the device may be employed to determine the in situ properties of well efliuents. Such modification takes the form of instrument means 62 positioned in chamber 57b. Said instrument means are interposed in conduit 63 communicating between the exterior of the tool and conduit 40, and may comprise a flowmeter, a thermometer, a pressure gauge, or any other instrument suitable for determining the properties of the fluid which enters chamber 57b via conduit 63. Instrument means 62 may be of the self-recording type or it may be a telemetering device which transmits the information it detects to the earths surface through an electrical conductor 65 which passes through the wall of conduit 40 via seal 66. Such devices are well known in the art.

In the preceding description of the operation of the devices of Figures 4 and 5 nothing was said concerning the manner in which the tool was removed from the well bore. In wells in which the eflluents from the various strata flow into the bore under more or less the same pressure, the sealing rings need not engage the well casing with any great degree of force, and in such instance the set tool may be withdrawn from the bore simply by lifting it with suflicient force to overcome the relatively small frictional resistance between the sealing rings and the well casing. In other cases, a refrigerating fluid may be forced down the central conduit to freeze the bodies of parafiiin wax, or other meltable material, thereby causing them to contract and allowing the resilient sealing rings to retract out of engagement with the well casing. Alternatively, the device itself may be so constructed as to be retractable. Such a form of device is shown in Figure 6.

Referring now to Figure 6, the device is shown positioned in a well bore prior to setting of the sealing elements. Said device comprises an upper conduit section 70, a middle conduit section 71, provided with perforations 72, and a lower conduit section 73. The latter, at its lower end, threadedly engages supporting plate 90 which rests on tool support 91 afiixed to the inside of well casing 79. Upper conduit section 70 is attached to the lower end of well tubing string 74 by coupling 75. Each of said conduit sections is threadedly joined to the adjacent conduit section through a packing element assembly 76 or 76a. Each of the assemblies 76 and 76a consists of upper and lower disc-shaped jaws, 77, 77a, 78 and 78a, respectively, having outside diameters less than the inside diameter of perforated casing 79 in which the tool is positioned. Each jaw is provided with a threaded central opening 80 which receives and engages the end of one ofthe conduit sections as shown, and is further provided with an inwardly projecting shoulder 81 which extends part-way across the inner diameter of the particular conduit section which the jaw engages. The

adjacent faces of upper and lower jaws 77, 77a, 78 and 78a are hollowed out back from their peripheries so that when the jaws are placed with said faces adjoining an annular space'exists between each pair of jaws. Resilient sealing rings 82 and 82a, having normal outside diameters less than the inside diameter of casing 79 and having inner diameters considerably greater than that of the aforesaid hollowed out portions of said jaws, are interposed between said jaws. A body 83a or 83b of solid material of suitable melting point fills the-remainder of the hollowed-out space between each pair of jaws. Spool-shaped members 84a and 84b having upper and lower shoulder portions 85a, 85b, 86a and 86b, respectively, are positioned within the conduit in such manner that upper shoulder portions 85a and 86a overlap shoulder portions 81 of upper jaws 77 and 78, respectively, and' lower shoulder portions 85b and 86b overlap shoulder portions 81 of lower jaws 77a and 78a, respectively. Spool-shaped members 84a and 84b are of such length that the upper and lower shoulder portions thereof are separated by a distance greater than the combined thickness of shoulder portions 81 of upper and lower jaws 77, 77a, 78 and 78a. When the device is lowered into the well bore the tool is somewhat loosely held together by spools 84a and 84b, i.e., middle conduit section will hang from spool 84a via the shoulder 81 of jaw 77a engaging shoulder 85b of spool 84a, and lower conduit section will hang from spool 84b via the shoulder of jaw 78a engaging shoulder 86b of spool 84b. Accordingly, jaws 77 and 77a and jaws 78 and 78a will be separated slightly and some lateral motion will be possible. However, by making sealing rings 82 and 82a only slightly smaller than the internal diameter of casing 79, such lateral motion is minimized, and the distance by which the jaws are separated can be kept at a minimum by suitable dimensioning of the spools. Should the bodies of meltable material be soluble in the well fluids, the well may be pumped dry or back pressure applied during lowering of the tool in the bore.

Alternatively, sealing rings 82 and 82a may be made sufiiciently resilient to fill the space between the pairs of jaws even though the jaws are separated to some extent. When the device is positioned within the casing, resting on tool support 91 as shown, the weight of tubing string 74 will maintain jaws 77 and 77a (and jaws 78 and 78a) tightly pressed together so that when bodies 83a and 83b of meltable material cannot exude between the respective jaws. When upper conduit section 70 and upper jaw 77 are raised, spool member 84a will likewise be raised by reason of its shoulder portion 85a engaging shoulder portion 81 of upper jaw 77, but lower jaw 77a will not be raised until its shoulder portion 81 is engaged by lower shoulder portion 85b of spool 84a. After the tool has been set" within casing 79 as a result of bodies 83a and 83b of solid material melting, when a lifting force is placed on well tubing 74, the jaws 77 and 77a of upper packing element assembly 76 will be pulled apart, thereby creating a larger enclosed space for the body of molten material and allowing sealing ring 82 to contract. If such lifting force is continued, jaws 78 and 78a of lower packing element assembly 76a will similarly be pulled apart by engagement of spool 84b with shoulder portions 81 of jaw members 78 and 78a. This arrangement permits the tool to be removed from the well after it has been set and sealing rings 82 and 82a expanded against casing 79, and, furthermore, 'allaws the seals to be broken one at a time.

The space between upper and lower packing element assemblies 76 and 76a and the exterior of middle conduit section 71 contains a body of a foraminous fluid-sensitive material 87 held in place by a screen or other foraminous retainer 88. Fluid-sensitive material 87 is of such nature that it undergoes an observable chemical or physical change upon being contacted with a particular well fluid. For example, it may comprise sawdust impregnated with a cobalt salt which changes color upon contact with water plugging or watefjshutotf, deyice. Fluid-sensitive mate} 87 may also"be oil-i'orjgas sensitiye in QId er to rpl ng'ofi'fs'nchfluida. L p a v menip b inggt e device provided byjthe invention at rl ativel y great 'depthsljt maybe necessary to proyide means tot prevent, the bodies offmeltabl e-i11aterialfrom p r n "(and sl et i th sea ng ri before V tl'ieitool reached its desired point of use Such meanslmay 'jsuitablycomprise thermal insulation applied to'thef exposedffaces' off the retaining plates. L Alterna: tiv ely; thetemperature within the well bore may be tempor'arily lowered to atyaluebelow the. melting point of theg'mel table material by circulating]agrefrigerant throngh th gwen bare prior to insertion'fof-the'tool. I a; :s'will" be appar nt .to those-[skilled in ,the art," the principlefof the present invention, may be appliedtola wide variety of packers, plugs other tools, and the device ofthe invention may takerman'y forms't other than those "illustrate'dfa'ndf described therein; Inits broadest aspect the'devi c'e" provided by the invention c'omprises an elongated body'porft'ion adapted to be lowered into 'a well bore Qat least .twolspaced retainirig members, extending from the outer snrfaceof the body member substantially perpendic ilar, to theaxis' jther'eof ae minucus resilientjeiipansiblesealing.ring held between adjacent retaining members adjacent the p eriphe riesthereqf and la bddyofinertfsolidmat'erial which expands'upon melti g V and which has lei-melting point between the atmospheric :te niperat'ufeattheearths surface and the ambien'ttem peratur e aft the point within the well bore whereth'tool is to be positioned, "said body of "solid 'material being held between adjacentretaining members and occupying Ithe space between the bodyportio'n and thesealing'ri'ng The trm'fineirt? is'intended "m1 lithium: body at 50nd ,mat er ialit o: those materials which do not chemically attack the 7 elements by which said bodies are-contained, Uthermodesi of applying the principle of our inventlon may be employedinstead oftho'seexplained, change being made as regar ds the elements or means employedjprov s g n p t s d-b y ita qwms ee or the equiyalent of stated apparatus beiconstructed arempibyea; t l V I We, therforq partienlarly point out and distinctly iclainiasloiir invention: i. 7 i

fadapted-tolbe lowered into a well bore; at least two spaced rigid retaining members "ifiixe d to 'said body portion and sit tending ontwardly from the longitudinal aii's thereof fthe opposedifaces of retaining ing o e r a snb stantial portion of the cross-sectional area of thewellbore; -a continuous annular resilient 'eirpansible sealing element ieirtending between opposed' fa'ces of hfijaeent retainingrnembers adjacent the peripheries there- 11161 as inga d 9dr' '9 9n at a is e e efr m; an body icl nert ter alisi iaefi ly fi lin the annular space enclosed by adjacent retaining membe rs and the sealing element associated therewith and "said bodymember, said material being one having a melting point 'abo e the temperature 'of'the atmosphere tatthe earthssurface but below thatatthe location within the {Well bore wheref the tool "is' to be emplbiled'and alsobeing o'newhich' increases 'in' voliime 'upon melting. Awai ed as defined by elaim 1" whereinsaid well tool comprising an elongated body portion t ofr and extending outwardly fromQsaid conduit in horiwhichrincreasesin'volume an ent of, at least. about P U P lmeltingL 7 3; 'Aiwell tool as defindab'y claim 11 wherinisaid Eddy V Constitutesaid'nppeii p air offbeiflg Substantially :circnl'ar and having diametefsfemallerfthan the linside diamet'erlof saidlwell bore; -21 lOW ei pa bf spa ced retaining ine'mbers aflixedto 'said conduit 'beloiiiv a"pe'r foratedfpor tion thereof and extending ou thh'ardly,"from said conduit in horizbntal planes Prbe fidicnlar to .{me' thereof, the opposed faces of the retaining. vmembers Whichcori jstitute ts'aid' lower pair being, substantially circular and having diameters smaller than'fthet inside diameter 'of saidwellxbdmj a continuous annular resilient ,eirpahsible sealirigjrin g 'extendihg betwen theopposed fabes' of the retaining mmbersiwhich: constitiite each vof said pairs adjacent the, peripheries". tlie'reof and surrounding said conduit at adistancetherefronigia body of inert material substantially. 511mg the annular space enclosed b etwen ith'e retainingfmem'bers which constitfite each of said'pairs and between each of said sealing elements and said conduitasaid material beingone haying a melting point'above t t mper u t i s ii$Ph a i i S face but that atthe location within" the T-viell bore where thetool to be employed-"and alsoibein g one which increases in yolnme upon melting; and a perforated V tubular member extending between saidupper and lower increasesjin yolume toan extentgof at'leastabout 1Q-per-' pent po k in i 1 r. a lj well tool comprising a hollow; elongatedconduit laterally "perforated over 1a portion of its; length and adapted to be lowered into 'a-well bore on-a welltubing in e uppe p g f sp e .n' ng-member.s affixed to saidconduit above a perforated; portion there,-

"zontal planes; perpendicular .toyfth'e longitudinal axis thereof, the opposed faces of 'the' retaining; members which constitute said upper pair being-,substantiallygcircnlar and having diameters smaller than-the inside diameter of said wellboreyalower 'pairiofspaced; rigid retaining members; affixed to, saidconduit below a perforated portion thereof and extending outwardly from said conduit in horizontaliplane'sjperpendicnlar to: the axis thereof, the opposed fac'es ofthe'fretaining menibers which constitute said lower pairbein'g Substantially circular and having diameters-"smaller :than' the inside diameter of saidwell here; a continuous annular resilient expansible sealing ring extending between :the opposed faces offthe retaining members which cons titute each 'ofsaid -pairsadjacent: the peripheries thereof and surrounding said conduit atadistance therefrom; 'a; body of inert material substantially 5 fillingvthe annulai space enclosed between' the retaining members which constitute reach of said pairs and-between each (of said sealing ielementsla'ndeaid conduitj-said material being-one having a melting point above the temperature of the' atmosphere at the earths surface but below that atthe location within-the well bore wherethe tool is 'to be employed and also-being 'one v"vhich "increasesin yolume upon' mel-tin'g; and a bodyof'a foraminous fluid-sensiti\ e material extending'betweenisaid upper and lower pairs of 7. A well tool as defined by claim 6 wherein said body of inert material consists of a hydrocarbon wax which increases in volume to an extent of at least about percent upon melting.

8. A well tool as defined by claim 6 wherein said foraminous fluid-sensitive material is a material which undergoes observable physical change upon being contacted with aqueous well efiiuents.

9. A well tool comprising a hollow elongated conduit laterally perforated over a portion of its length and adapted to be lowered into a well bore in a well tubing string; an upper pair of spaced rigid retaining members afiixed to said conduit above a perforated portion thereof and extending outwardly from said conduit in horizontal planes perpendicular to the longitudinal axis thereof, the opposed faces of the retaining members which constitute said upper pair being substantially circular and having diameters smaller than the inside diameter of said well bore; a lower pair of spaced rigid retaining members al'fixed to said conduit below a perforated portion thereof and extending outwardly from said conduit in horizontal planes perpendicular to the axis thereof, the opposed faces of the retaining members which constitute said lower pair being substantially circular and having diameters smaller than the inside diameter of said well bore; a continuous annular resilient expansible sealing ring extending between the opposed faces of the retaining members which constitute each of said pairs adjacent the peripheries thereof and surrounding said conduit at a distance therefrom; a body of inert material substantially filling the annular space enclosed between the retaining members which constitute each of said pairs and between each of said sealing elements and said conduit, said material being one having a melting point above the temperature of the atmosphere at the earths surface but below that at the location within the well bore where the tool is to be employed and also being one which increases in volume upon melting; and a body of a foraminous fluid-sensitive material disposed exterior of said conduit and extending across each of the perforations therein.

10. A well tool as defined by claim 9 wherein said body of inert material consists of a hydrocarbon wax which increases in volume to an extent of at least about 10 percent upon melting.

11. A well tool as defined by claim 9 wherein said foraminous fluid-sensitive material is a material which undergoes observable physical change upon being contacted with aqueous well efiiuents.

12. A well tool comprising a hollow elongated conduit laterally perforated over a portion of its length and adapted to be lowered into a well bore in a well tubing string; an upper pair of spaced rigid retaining members aflixed to said conduit above a perforated portion thereof and extending outwardly from said conduit in horizontal planes perpendicular to the longitudinal axis thereof, the opposed faces of the retaining members which constitute said upper pair being substantially circular and having diameters smaller than the inside diameter of said well bore; a lower pair of spaced rigid retaining members affixed to said conduit below a perforated portion thereof and extending outwardly from said conduit in horizontal planes perpendicular to the axis thereof, the opposed faces of the retaining members which constitute said lower pair being substantially circular and having diameters smaller than the inside diameter of said well bore; a continuous annular resilient expansible sealing ring extending between the opposed faces of the retaining members which constitute each of said pairs adjacent the peripheries thereof and surrounding said conduit at a distance therefrom; a body of inert material substantially filling the annular space enclosed between the retaining members which constitute each of said pairs and between each of said sealing elements and said conduit, said material being one having a melting point above the temperature of the atmosphere at the earth's surface but below that at the location within the well bore where the tool is to be employed and also being one which increases in volume upon melting; a tubular member extending between said upper and lower pairs of retaining members adjacent the peripheries thereof; and controllable valve means in register with a perforation in said tubular member for establishing and disestablishing communication between the exterior of the tool and the annular space between said tubular member and said conduit.

13. A well tool as defined by claim 12 wherein said body of inert material consists of a hydrocarbon wax which increases in volume to an extent of at least about 10 percent upon melting.

14. A well tool as defined by claim 13 wherein means for detecting physical conditions within the annular space between said tubular member and said conduit are positioned therein. 7

15. A well tool comprising an elongated body portion adapted to be lowered into a well bore on a well tubing string; a plurality of circular rigid retaining plates afixed to said conduit and extending outwardly therefrom in horizontal planes perpendicular to the longitudinal aixs thereof, said retaining plates having diameters smaller than the inside diameter of said well bore and being afi'ixed to said conduit in a configuration of a plurality of spaced pairs; a plurality of continuous annular inert resilient expansible sealing rings, each of which extends between the opposed faces of the retaining plates which constitute each of said pairs adjacent the peripheries thereof; a body of inert material substantially filling each of the annular spaces defined by said conduit and the opposed faces of the retaining plates which constitute each of said pairs and the sealing ring associated therewith, said inert material being one having a melting point above the temperature of the earths surface but below that at the level it occupies within the well bore when the tool is in use and also being one which increases in volume upon melting; and a plurality of perforate tubular members each of which extends between adjacent pairs of said retaining plates adjacent the peripheries thereof.

16. A well tool as defined by claim 15 wherein said body of inert material consists of a hydrocarbon wax which increases in volume to an extent of at least about 10 percent upon melting.

17. A well tool as defined by claim 15 wherein said elongated body portion is a hollow conduit and means are disposed within the annular spaces between said tubular members and said conduit for placing said annular spaces in communication with said conduit.

18. A well tool as defined by claim 15 wherein said tubular members are perforated and said conduit is perforated over those portions of its length which extend between adjacent pairs of said retaining plates.

19. A well tool as defined by claim 15 wherein means for detecting physical conditions within the annular spaces between said tubular members and sad body member are positioned within at least one of said annular spaces.

References Cited in the file of this patent UNITED STATES PATENTS 1,998,915 Young Apr. 23, 1935 2,781,663 Maly et al. Feb. 19, 1957 2,814,947 Stegemeier et al Dec. 3, '1957 UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,942,668 June 28, 1960 George P. Maly et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the drawings, Sheet 2, containing Figures 5 and 6, as shown below should be inserted as part of the Letters Patent:

Jame 28, 196%) G. P. MAL? ETAL 2,942,658

aw. PLUGGING. PACKING AND/OR wes'rmc TOOL filed New. 19, 1957 2 Sheets-Sheet 2 t a h s is A EL" 2 f A 7 C1 .5 I: j i

i l e Z a ll 2% i an 1 A T is/ m Eras l w 7 1 l l 1' E'za- M mm: 9015124140; fan 41.04. Fuzz 8/ fl n! Q Alf-i3 dwwzx in the heading to the present sheet of drawing, line 3, to the right of the filing date, insert 2 Sheets-Sheet l-.

Signed and sealed this 15th day of November 1960.

Attest KARL H. AXLIN E,

ROBERT C. WATSON, Commissioner of Patents.

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