Abstract: A controlled release method for a submergible completion is disclosed wherein upper and lower interface assemblies are separated from one another in a predictable manner. A separation or release assembly is actuated remotely for forcing the interface assemblies apart. The release assembly may shear pins extending between portions of the interface assemblies. The interface assemblies may include multi-conductor electrical plugs or connectors which are separated during release.

Abstract: An apparatus for opening perforations in a casing string. The casing string has a special casing section defining a plurality of holes therethrough. Rupturable ceramic discs or inserts are disposed in said holes and retained therein. The ceramic discs or inserts are adapted to withstand the fluid differential pressures normally present in the wellbore but are rupturable in response to impact by a mild explosive charge. The explosive charge is provided by detonating a length of det-cord disposed in the casing string adjacent to the holes in the special casing section. A method of perforating using this apparatus is also disclosed.

Abstract: A plug apparatus is provided which includes a dispersible plug member and a fluid barrier. In one embodiment described herein, a fluid barrier is utilized to prevent contamination of fluid contained in a plug apparatus. The fluid is thus available for use in dispersing a plug member of the plug apparatus, regardless of the types of other fluids present in a well in which the apparatus is installed. Various configurations of fluid barriers are also provided.

Abstract: A downhole choke and associated methods provide enhanced efficiency and accuracy in well sampling and testing operations due to its capability for substantially minimizing the amount of time needed to establish steady state flow conditions in a well, and the ability to sample fluids downhole at varying downhole flow restrictions. In a described embodiment, a downhole choke is operable to restrict fluid flow therethrough by applying a predetermined fluid pressure to an annulus formed between the choke and the wellbore. The downhole choke has an axial flow passage formed therethrough, a portion of which has interchangeable flow areas. The flow areas are interchanged upon application of the predetermined fluid pressure, and again interchanged upon expiration of a time delay. One of the flow areas permits substantially unrestricted fluid flow therethrough, and another of the flow areas permits restricted flow therethrough.

Abstract: A packer mill system for milling a packer in a wellbore has been invented which has, in certain aspects, a bushing with a hollow generally cylindrically shaped bushing body with a bottom, a top, a bushing bore extending therethrough from top to bottom, and at least one key on an interior surface thereof, the at least one key projecting inwardly into the bushing bore, a mandrel initially disposable within the bushing, the mandrel having a hollow generally cylindrically shaped mandrel body with a top, a bottom, a mandrel bore extending therethrough from top to bottom, and a slot system formed in an exterior surface of the mandrel body, the at least one key disposed for movement through the slot system, engagement apparatus connected to the bottom of the mandrel body for engaging the packer, milling apparatus connected to the bottom of the bushing body and disposed for movement therethrough of the engagement apparatus, the slot system having a series of one or more interconnected slots through which the at least

Abstract: A retrievable screen apparatus provides increased filtration in a retrievable screen disposed within a receptacle, the receptacle being positioned in a subterranean well. The receptacle has a lower filtration screen attached thereto for filtering larger particles, such as gravel and proppant, from fluid flow within the well. Thus, the retrievable screen may be retrieved and replaced, leaving the receptacle operatively positioned in the well.

Abstract: There is described a method of rotatably connecting the downhole end of a tubing string to a tubing anchor in a well bore, the method comprising the steps of connecting the downhole end of the tubing string to a first tubular sub, connecting the tubing anchor to a second tubular sub, providing an initial connection between the first and second tubular subs preventing both relative rotation and axial separation therebetween, fixing the tubing anchor in place in the well bore by means of torque transmitted through the tubing string and the first and second tubular subs to the tubing anchor, and rupturing the initial connection between the first and second tubular subs by means of tension applied to the first tubular sub, whereupon the first and second tubular subs may be axially separated by a predetermined amount so that one can rotate relative to the other and so that the tubing string is then rotatable relative to the tubing anchor.

Abstract: Methods and apparatus are provided for draining or removing well fluid from a production tubing string into a well borehole while pulling the tubing string from the well. A special length of tubing is provided near the lower end of the tubing string with a drain port communicating the interior and exterior of the tubing. The drain port is initially plugged and sealed with a knock out plug. When it is desired to remove the tubing string from the well and drain its fluid into the borehole, a drop sleeve is dropped from the surface to shear and open the knock out plug. A sleeve stop catches the drop sleeve for re-use.

Abstract: A method of removing a pipe string anchored in cement within a wellbore involves the use of a coupling cutter having a linear charge that is magnetically oriented radially and rotationally within the pipe. The coupling cutter also has a coupling sensor that identifies the location of a coupling electronically. One first determines the free length of pipe that is above the cement. The coupling sensor then finds the lowest coupling that is just above the cement level so that the linear charge can be axially aligned to that coupling. A magnet on the cutter properly orients the linear charge both radially and rotationally relative to the inner wall of the pipe. The charge is detonated to longitudinally split the coupling. The pipe string is then disassembled and pulled from the wellbore.

Abstract: The invention relates to an releasable grip arrangement providing an impermeable barrier in an annular space between an inside tube and an outside tube of an oil well and is made of a material which may be dissolved by a suitable solvent and includes a seal member and a locking member 3, a sleeve which comprises holes which can be blocked during normal use but can be opened to permit the entrance of a solvent.

Abstract: Systems and methods for cutting a well casing and then capping the cut well casing are provided. A well casing cutting assembly having a tensioned wire cutting element may first be moved into position relative to the well casing and operated so that the cutting element reciprocates transversely (i.e., in saw-like fashion) while simultaneously being advanced forwardly into cutting relationship with the well casing. The cutting assembly is removed from the cut well casing and replaced with a well capping assembly having a shield enclosure and a thread cutting subassembly. The thread cutting subassembly includes an interiorly threaded pipe coupling which rigidly carries a normally open, remotely controlled valving assembly and is mounted to the shield enclosure so as to be capable of both rotational and vertical movements relative to the cut well casing.

Abstract: A downhole tool, comprising one or more separate packers and sliding sleeves in the preferred embodiment, is actuable from a nonelectrical signal transmitted from the surface to the tool. The signal is received at the tool by a control system located within the tool. The control system operates in conjunction with a power supply in the tool to accomplish tool actuation. In the preferred embodiment, the valve member is temporarily retained in a sealing position, isolating pressure in one chamber from a different pressure in an adjacent chamber. The valve member or piston is temporarily retained by a high-strength fiber, such as Kevlar.RTM., in the preferred embodiment. The control system actuates the power source to heat a resistance heating wire, which causes failure in the fiber. Other mechanisms to trigger pressure-equalization can be used. The fiber can be cut by a cutter actuated electrically. The piston can be retained by solder which is melted electrically.

Abstract: Preperforated tubing is produced by forming a perforation in flat strip of raw material, forming a hollow, cylindrical tube from the flat strip, and placing a removable plug into the perforation, so as to form a fluid-tight seal. A sealing element may be placed into the perforation. The perforation may comprise a hole, into which first and second countersinks may be formed. The sealing element may be placed into the first countersink, and the plug may be placed through the countersinks and the hole, such that the plug's body fills the hole and the plug's head fits within the second countersink.

Abstract: A ported fluid flow member has been developed in which one or more ports each is lined with a metal tube which has a portion projecting into the body member. The projecting portion may be crushed shut forming a metal-to-metal seal to seal off the corresponding port to flow. Methods have been invented for using the items with one or more of the lined ports.

Abstract: The perforations of a pre-perforated tubular are plugged with interior protruding, mostly hollow plugs which temporarily seal the perforations. The plugs are capable of withstanding a significant pressure differential and, when combined with an insert, forming a flotation cavity containing a buoyant fluid. The temporarily sealed tubular is then run into a wellbore, the tubular is set, and the plugs are unsealed. The unsealing is preferably accomplished by drilling out the interior protruding portions. Solid baffles may also be placed in the string to limit buoyant fluid loss in the event of premature unsealing in another embodiment of the invention.

Abstract: A mill assembly having a mill face for milling material in a downhole milling operation is received in a casing or well bore having an internal wall having a first diameter. The mill face has a smaller diameter than the first diameter. The mill face is connected to a shaft assembly including a shaft and a stabilizing assembly for stabilizing the shaft in the casing or the well bore. The stabilizing assembly is connected at one end to the mill face and has a smaller diameter than the first diameter. The stabilizing assembly includes a stem having one or more tapered surfaces, the tapered surfaces tapering from a first diameter to a second diameter larger than the first diameter. The stabilizing assembly further includes a plurality of roller bearings circumferentially arranged in a plane around the stem, each roller bearing being in contact with one of the tapered surfaces at a first point.

Abstract: A fracture oriented completion tool system for use in a casing string in a wellbore. The completion tool comprises a casing valve having a radioactive source therein, the orientation of which may be determined by use of a detector apparatus, such as a rotational gamma ray detector. The casing valve thus may be aligned with the fracture of a zone of interest in the well. A plurality of casing valves may be used, with at least one having a radioactive source. A swivel connection may be used to interconnect the casing valve so that housing ports therein may be aligned as the casing is run into the wellbore. In one preferred embodiment, the swivel connection is a locking swivel connection. A method of positioning a casing string in the well utilizing the completion tool is also disclosed.

Abstract: A method and an apparatus for use in a wellbore are provided to prevent an electrical current from passing between a power supply and an electrically operated downhole well tool until after the electrically operated downhole well tool is positioned downhole within the wellbore. A temperature sensitive member prevents a biased member from moving from a first position to a second position until after the temperature sensitive member has been heated to an activation temperature, at which the temperature sensitive member softens to allow the biased member to move through the temperature sensitive member and to the second position for electrically connecting between the power supply and the electrically operated downhole well tool.

Abstract: The flow apertures of a perforated mandrel are temporarily sealed by a foil covering sheet which is made of a sacrificial material, for example, zinc, aluminum and magnesium The sacrificial covering sheet prevents dirty completion fluid from passing through and in and out of the screen as it is run into the hole, thereby protecting the screen from plugging. During the time the screen mandrel is temporarily sealed by the sacrificial foil covering, cleaning fluid is circulated through the work string and is returned through the annulus between the screen and the open well bore for removing filter cake, drilling debris and lost circulation material. After the annulus has been cleaned, the annulus is filled with an acid solution or caustic solution, which dissolves the sacrificial foil and opens the base pipe perforations.

Abstract: An automatic tubing release mechanism is adapted to be disposed in a wellbore between a tubing, on one end, and a perforating gun, on the other end. The release mechanism includes a frangible breakup tube, firing head positioned above the breakup tube, and the perforating gun positioned below the breakup tube when the release mechanism is disposed in the wellbore. A detonating cord is interconnected between the firing head and the perforating gun via the breakup tube. When the firing head detonates the perforating gun, the breakup tube shatters.

Abstract: A procedure for drilling out a cement plug from a liner top using a drill bit with extendible cutting elements to avoid the need for changing bits during the procedure.

Abstract: A downhole tool apparatus and methods of drilling the apparatus. The apparatus may include, but is not limited to, packers and bridge plugs utilizing non-metallic components. The material may include engineering grade plastics. The nonmetallic components may include but are not limited to the center mandrel, slips, slip wedges, slip supports and housings, spacer rings, valve housings and valve components. Methods of drilling out the apparatus without significant variations in the drilling speed and weight applied to the drill bit may be employed. Alternative drill bit types, such as polycrystalline diamond compact (PDC) bits may also be used.

Abstract: A well service tool has a mandrel including a fluid flow conduit therethrough in fluid communication with a workstring including a fluid pressure source. An expendable knife-mounting sleeve is coupled to the mandrel and includes at least one cutting knife pivotally secured thereto. A housing is disposed about and secured against rotation relative to the mandrel by drive pins and is selectively movable relative to the mandrel responsive to fluid pressure from the fluid pressure source. The housing includes a positive extender to extend the cutting knives and temporarily maintain them in an extended position. A closure member is coupled to the mandrel to selectively obstruct fluid flow through the fluid conduit, wherein fluid pressure within the fluid conduit is increased, and wherein relative movement between the housing and the mandrel is induced. A probe is coupled to the housing to open the closure member upon a selected extension of the cutting knives wherein fluid pressure within the mandrel is decreased.

Abstract: Under-balanced or potential fluid cross-flow conditions in a wellbore are minimized during installation of an auger-type gravel pack screen by placing a quantity of fine salt, calcium carbonate paste, a fluid loss control gel or sand within the interior space of the screen liner so that the material will form a substantially impermeable barrier on the liner, the gravel packing or the face of the formation during or after installation of the screen to minimize fluid flow in wells which have a relatively high pressure gradient. The material may be removed at will by circulation of a dissolving liquid such as fresh or unsaturated water or mechanical removal of insoluble material such as sand.

Abstract: This invention relates to a downhole activated centralizer for centralizing pipes in a wellbore for the exploration and production of hydrocarbons. The downhole activated centralizers are carried within either the pipe casing or the collars or both and remain generally within the maximum outward profile of the pipe string so as not to interfere with the movement and placement of the pipe string in the wellbore. The pipe string may be rotated, reciprocated and circulated which enhances the ability of the installer to place the pipe string in a deviated or long reach wellbore. Once the pipe string is in place, the centralizers may be deployed by one of several methods such that pistons mounted in openings in the peripheral wall of the pipe string move outwardly with sufficient force to move the pipe string way from the walls of the wellbore sufficient to form a complete annulus for cementing.

Abstract: A safety valve landing nipple selectively provides communication between a surface control line and the internal bore of said landing nipple by use of a rotary member. A rotary shifting tool is used to rotate the rotary member so that a cutting means shears the end of a shearable plug in the wall of the landing nipple, so as to provide communication between the surface control line and the internal bore of the landing nipple. A method of providing communication within a landing nipple between the surface control line and the internal bore of the landing nipple by use of the rotary shifting tool and a rotary shifting tool having a rotatable outer mandrel means, an inner mandrel means, a travel means and a diametrically retractable means.

Abstract: An isolation valve for a downhole well completion system having a one piece frangible, ceramic sealing element and an extrusion resistant resiliently faced valve seat and a method for the use thereof is presented. Said sealing element is biased to the closed position and rotatable within a sealing element chamber from an open position during run in to a closed position as a result of the withdrawal of a wash pipe and a protector tube from the valve bore. Said frangible sealing element cooperates with said extrusion resistant valve seat to provide a reliable pressure resistant seal. After recovery of completion fluids from the well bore and pressure testing of the production string, the frangible sealing element is shattered by impacting with a tooth-faced blind box hammer.

Abstract: An expendable plug is shown for use in a well bore tool for controlling the flow of well bore fluids from a production zone to the well surface. The plug is located within a tubular housing which is made up in a well tubing string having an internal bore with a predetermined minimum internal diameter. The plug initially closes off the internal bore of the tubing string at a selected location. An actuator is triggered by an appropriate signal to expend the plug of expendable material, and to remove the plug from the internal bore of the tubing string, whereby fluids in the surrounding earthen formation are allowed to flow up the tubing string to the well surface.

Abstract: A liner at the bottom of an oil or gas well is perforated and the surrounding formation is subsequently fractured by inserting into the liner a perforating and fracturing apparatus comprising a pair of packers that can be positioned around fragile spots of the liner, and subsequently injecting a fluid or fluids at an elevated pressure into the area between the packers in order to perforate the liner at the locations of the fragile spots and to create fractures in the formation surrounding these spots.

Abstract: An underreamer tool has a body with upper and lower portions having an upper cutter blade slot extending transversely through the upper portion and a lower cutter blade slot extending transversely through the lower portion at a right angle thereto. The upper and lower portions have central bores separated by a wall and connected by upper and lower fluid flow passageways bypassing the cutter blade slots. An upper pair of cutter blades mounted in the upper cutter blade slot and a lower pair of cutter blades mounted in the lower cutter blade slot move between a retracted position within the slots and an extended position outward therefrom. An upper piston in the central bore above the upper cutter blade slot has its bottom end engaged on the upper cutter blades and a lower piston in the central bore above the lower cutter blade slot has its bottom end engaged on the lower cutter blades.

Abstract: A tool and method for use with a drill string or the like in capturing an object in a cavity, such as subterranean borehole, include a mandrel, object engaging apparatus for latching the mandrel to the object as the tool is moved into the borehole, and string engaging apparatus for keeping the mandrel latched to the drill string as the mandrel is moved into the borehole and for unlatching the mandrel from the drill string when the drill string is rotated in a first direction with the mandrel latched to the object. A washover pipe and mill, which are connected to the drill string, may be moved into contact with the object after the mandrel is unlatched from the drill string for milling through the object. A ratchet allows the mill to move toward the object relative to the mandrel and prevents the mill from moving away from the object relative to the mandrel. The ratchet allows the mill to move away from the object when the drill string is rotated in the first direction and lifted relative to the mandrel.

Abstract: An underreamer tool has a body with upper and lower portions having an upper cutter blade slot extending transversely through the upper portion and a lower cutter blade slot extending transversely through the lower portion at a right angle thereto. The upper and lower portions have central bores separated by a wall and connected by upper and lower fluid flow passageways bypassing the cutter blade slots. An upper pair of cutter blades mounted in the upper cutter blade slot and a lower pair of cutter blades mounted in the lower cutter blade slot move between a retracted position within the slots and an extended position outward therefrom. An upper piston in the central bore above the upper cutter blade slot has its bottom end engaged on the upper cutter blades and a lower piston in the central bore above the lower cutter blade slot has its bottom end engaged on the lower cutter blades.

Abstract: A casing mill for milling pipe cemented in an oil well comprises a body with a plurality of fixed milling blades having a diameter corresponding to the outside diameter of the pipe to be milled, and a second plurality of movable blades movable between a retracted position smaller than the inside diameter of the pipe to be milled, and an extended diameter corresponding to the outside diameter of a pipe coupling between adjacent sections of pipe. Means are provided for selectively moving the blades between the retracted and extended positions in response to drilling fluid flow. A stabilizer keeps the casing mill centered in the pipe to be milled. In this way, one can mill both the pipe and coupling in the vicinity of a coupling and mill only pipe between the vicinities of adjacent couplings.

Abstract: A downhole tool, such as a safety valve or a stand-alone nipple, has a tubular housing. An axially extending bore is provided in the wall of the housing. A radially extending recess is provided in the internal bore wall of the housing, encompassing the axially extending bore, and a control fluid pipe is passed through the bore and the recess. A cutting tool is mounted for radial movements in the recess and is actuated by downward jarring forces imparted by an auxiliary tool. The control pipe is severed by the cutting element and the lower severed end portion of the control pipe is concurrently crimped to close such end portion.

Abstract: A well is completed by cementing a casing string in place in the well. A jetting tool assembly is run into the casing string on a tubing string. The jetting tool assembly engages a sliding sleeve of a casing valve and slides the sliding sleeve to an open position uncovering a plurality of housing ports in the casing valve housing in which the sleeve is received. Then, disintegratable plugs are hydraulically jetted from the housing ports to communicate a subsurface formation adjacent the casing valve with an interior of the casing string. Preferably, prior to opening the sleeve and hydraulically jetting the plugs, residual cement is drilled from the casing string, then further residual cement is hydraulically jetted from the casing valve, and then the casing valve is backwashed by reverse circulation.

Abstract: A method and apparatus for replacing a defective downhole well safety valve of the full bore type by a wireline valve sealably insertable in the bore of the housing for the defective valve by wireline and operating the wireline inserted safety valve by fluid pressure supplied through an existing control fluid passage provided in the original safety valve housing. An internally projecting integral protuberance is provided in the bore of the original safety valve housing and a connecting fluid conduit is provided between the interior of the protuberance and the existing control fluid passage. A cutting tool is mounted on an axially shiftable sleeve disposed immediately above the protuberance. The axially shiftable sleeve is manipulated by an auxiliary tool temporarily inserted in the bore of the original valve housing and causing the cutting tool to remove the protuberance and thus establish fluid communication for the control fluid with the internal bore of the original safety valve housing.

Abstract: A gravel packing process employs a staged screen assembly to prevent sand and other fine particles entrained in the produced hydrocarbon fluids from entering the production tubing and related equipment. The staged screen assembly is provided with a base pipe having rupture disks in its sidewall. The disks rupture at a predetermined pressure differential during gravel packing to enable leakoff of the carrier fluid from the gravel slurry into the base pipe and recirculation of the carrier fluid back to the wellhead, while ensuring complete and uniform gravel packing of the hydrocarbon production interval without substantial bridging or duning.

Abstract: A detonation assembly for an explosive wellhead severing system which employs a battery pack lowerable through a drill string to engage and power the detonation assembly positioned within the well bore. The lowerable unit includes a biased shutter which seals the contacts from discharge of the battery pack by the surrounding fluids. The shuttered unit is lowered into contact with the receiving unit to arm the detonation assembly. Until the power unit is lowered into engagement, the severing system is not armed. In case of malfunction or misfire, the power unit can be retrieved to disarm the detonator assembly. The entire assembly is housed within the drill string to isolate the critical elements from the surrounding environment.

Abstract: A chemically removable casing section is spotted in a casing string opposite a formation through which a horizontal borehole is to be drilled. The casing section is selectively dissolved by a chemical solution, and a horizontal borehole is drilled into the formation through the window in the casing string.

Abstract: Disclosed are a method and an apparatus for cutting conduits. The apparatus includes a cutting head adapted for insertion in the conduit. The cutting head has at least one nozzle. The cutting head is rotatable to locate a previously cut sector of the conduit. A decentralizer is provided for positioning the nozzle adjacent a portion of the conduit.

Abstract: In a downhole staging apparatus for delivering fluidized cement sequentially into two levels of substrate which enclose a wellbore casing. Said apparatus comprises a primary cement discharge port, and one or more secondary or lateral cement discharge ports. A sleeve is operably carried in the apparatus, being adjustable to close the secondary lateral port when a cementing operation is completed. A sleeve actuating tool is cooperative with said cementing apparatus, being remotely operable to close the lateral cement discharge port to assure that no communication exists between the cementing apparatus and the wellbore after the cementing operation is completed.

Abstract: An easily drillable production packer for use in testing, treating and squeeze cementing operations in wells which may be easily converted by securing an appropriate baffle, profile, valve assembly or plug assembly to the lower end of the mandrel thereof.

Abstract: A down-hole oil field cable abrader having an elongated abrading head pivotally connected at one of its ends to a body attachable to a tubing string. An abrading portion extends axially along the abrading head from its pivotal connection and includes a plurality of abrading elements, similar to the cutting elements on a drill bit, spiralling axially about the abrading head ending in a taper to an area distal to its pivotal connection.

Abstract: A bridge plug having upper and lower slips for anchoring the plug and an elastomeric packing element for sealing within a well casing. The bridge plug may be set either mechanically or through a wireline pressure setting assembly. The small outer diameter of the bridge plug allows for fast run in and the short design and material selection assures a quick drill-out. The lower cone adjacent the lower slip assembly is locked to prevent spinning of the plug during drill out. Pressure equalizing means are provided for equalizing the fluid pressure above and below the plug before drilling out the upper slips.

Abstract: For use in a wellbore, a connector assembly for connection to and use with a variety of downhole tools and apparatuses and methods for effecting such use; and tools including such a connector assembly in combination and methods for the use of such tools. The connector assembly has a T-shaft with shoulders extending therefrom and a slot cylinder for receiving, holding, and supporting the T-shaft. Slots and recesses are provided in the slot cylinder for receiving, transmitting and encompassing the T-shaft's shoulders.

Abstract: A capsule for conveying chemicals through a borehole for stopping lost circulation is totally made from a thermoplastic or fragile material or has a bottom plate made from such a material. The capsule containing the chemicals is let down until it reaches the location of the lost circulation, where the capsule is either destroyed by a drilling rod or softened by the high temperature and high pressure at the location. Thus, the chemicals are diffused.

Abstract: Disclosed is apparatus and method for a system useful in establishing a metal to metal seal between conduit joints in wells. A milling tool having means controlling down force on and positioning the cutter is used to cut and/or finish a seat on a shoulder in a well conduit, which will mate and seal with metal seal surfaces on seal units lowered on conduits into the well. One seal unit has elastomeric seals in addition to the metal seals.

Abstract: A downhole tool for controlling the flow of fluids through the well casing includes a tubular mandrel with a flow control valve therein. A radially expandable seal member encircles the mandrel and a sub-bottom defines an abutment member, attached to and movable with the mandrel, for engaging one side of the seal member. A bottom cone is positioned around the mandrel and on the opposite of the seal member from the sub-bottom. The cone has a sleeve extending therefrom positioned between the seal and the mandrel on which the seal member is carried. An upper cone is positioned around the mandrel with slips segments being positioned between the upper and bottom cones. An upper radially expandable seal member encircles the mandrel and its carried on a sleeve extending from the upper cone. A lock hub is positioned around the mandrel and on the side of the upper cone opposite the upper seal and slip segments.

Abstract: A capsule for conveying chemicals through a borehole for stopping lost circulation has a fragile bottom plate. A weight for destroying the bottom plate is suspended above the capsule by a cord which extends over knife edges. A messenger for cutting the cord is mounted to a wire line. The weight is caused to collide with the messenger to cut the cord, for breaking the bottom plate. Thus, the chemicals are diffused.

Abstract: A well packer adapted to be set in a well conduit and includes a mandrel, a packing seal surrounding the mandrel and slips positioned above the packing seal against an abutment. The abutment is connected to a latching head and to the mandrel. A connection is positioned adjacent the lower end of the latching head which can be broken for releasing the latching head and preferably the abutment from the mandrel for allowing the milling out of the packer without the necessity of milling the latching head. The packer is released by an upward jar on the latching head for retrieving the latching head in some embodiments and by chemical cutting in another embodiment. The packer slips are then milled out for releasing the packer for upward movement.