Abstract: A fluid powered downhole vibration tool used in a well bore having fluids under pressure. The tool includes a resonant chamber with a through passage in communication with the fluids under pressure wherein the chamber vibrates as the fluids pass through the passage. The resonant chamber is coupled to the well bore, causing vibration of the bore as the chamber vibrates.

Abstract: A packer for use inside a casing of a subterranean well includes a resilient element, a housing and a rupture disc. The resilient element is adapted to seal off an annulus of the well when compressed, and the housing is adapted to compress the resilient element in response to a pressure exerted by fluid of the annulus of a piston head of the housing. The housing includes a port for establishing fluid communication with the annulus. The rupture disc is adapted to prevent the fluid in the annulus from entering the port and contacting the piston head until the pressure exerted by the fluid exceeds a predefined threshold and ruptures the rupture disc.

Abstract: One or more downhole tools can be set using an apparatus and method where a control line runs outside a tubular string. The string and downhole tools do not have lateral penetrations and the downhole tool(s) are actuated externally from the control line which is in the annular space.

Abstract: A fluid powered downhole vibration tool used in a well bore having fluids under pressure. The tool includes a fluid powered motor located within the well bore, the fluid powered motor is in communication with the fluids under pressure. An actuator coupling is rotated by the fluid powered motor. A seismic mass is rotated in the well bore by the actuator coupler, the seismic mass engaging the well bore and causing vibration of the well bore.

Abstract: Completion method for avoiding formation impairment in the completion of a wellbore by anchoring and activating a plug at a selected position in the wellbore to seal off a selected portion of the wellbore from other portions of the wellbore. The plug is positioned at the selected position in the wellbore and anchored at that position. A seal in the plug is then activated such that fluid cannot pass the plug. Other parts of the wellbore can then be operated at different pressures than the isolated part of the wellbore without impairment of the formation resulting from the loss of well fluids into the formation.

Abstract: A frangible sealing disk for use downhole in combination with packer components. The sealing disk is a molded ceramic disk having a circular seating face and extending centrally through a dome-shaped seal. The seal is preferred for use in combination with a packer assembly for pressure sealing the borehole, either up hole or down, so that the seal may be broken away easily when it is desired to remove or reset the packer assembly.

Abstract: The invention relates to a safety packer assembly for use in a cement-lined pipe. The assembly provides for the use of a packer body which carries one or more resilient collars that expand in response to a compression force created by rotation of an upper part of the packer body. A safety valve is provided in the upper part of the packer body to prevent escape of the downhole pressure. A safety centralizer is detachably secured to a lower part of the packer body, the centralizer being provided with a plurality of arcuate resilient members which extend along the length of the centralizer body and frictionally contact the wall of the cement-lined pipe to maintain the packer body in its predetermined position within the pipe and resist rotation of a lower part of the packer body when the upper part is rotated.

Abstract: A set of inflatable well packing elements are separated by a variable length of tubing and are set in a well to isolate a segment of the annulus by applying fluid under pressure through a tubing string to the well packing elements. The flow of the fluid under pressure to the inflatable packing elements is regulated by a flow control valve which automatically cuts off the fluid flow at a predetermined tubing to annulus pressure differential and opens communication between the tubing string and the isolated well zone. Fluid may thereafter be pumped into or swabbed from the isolated zone. Upon completing the zone servicing, pulling the tubing string up slightly will both equalize the pressure across the inflatable packing elements, and deflate the packing elements. Thereafter, the tubing string may be retrieved from the well or, if desired, moved to another location which can be serviced in the same manner.

Abstract: A test plug for sealing a bore within a tubing hanger comprising an annular plug body having an axial bore extending therethrough, the axial bore forming a tapered annular seat and an enlarged receptacle within the plug body; a plurality of support dogs retractably mounted within corresponding slots formed in the plug body adjacent a lower portion of the receptacle; a mandrel slidably received within the receptacle, the mandrel having a downwardly and outwardly facing cam surface formed on a lower portion thereof; and a stinger having a tapered closure member adapted to be received in the annular seat, a spring for biasing the closure member against the seat and a seal ring for providing a fluid-tight seal between the closure member and the seat; wherein each support dog comprises an inner beveled edge formed on an upper portion thereof which preferably matches the cam surface of the mandrel, such that when the mandrel is set the cam surface will engage the beveled edge and urge the support dogs into an annul

Abstract: A hollow body is provided with a seal by which it may be sealed within a nipple profile included in a tubing string. The body allows a wireline to be passed through it while maintaining a substantial seal. During running-in lower collet fingers engage a stop ring mounted on the body. When the plug becomes seated in the nipple profile by the weight of a logging tool also suspended on the wireline, fingers are disengaged by inward movement of external collet fingers and rollers. Consequent downward movement of the fingers allows the rope socket to push them outwardly and allows the logging tool to be lowered. An equalizing sleeve can be pulled up by the socket head from the sealing position to a raised position which allows pressure equalization above and below the plug to facilitate withdrawal thereof. Profiles on the fingers act to trap the socket head should the wireline pull out or break.

Abstract: A casing inflation packer for use in a casing string in a well bore. The apparatus includes a housing connected in the casing string. An inflatable packer portion on the housing sealingly engages the well bore when inflated. An inflation passageway is defined between a housing central opening and the packer. A rupture disc is initially disposed between the central opening and the inflation passageway for preventing communication therebetween. The rupture disc ruptures in response to a first predetermined pressure, thereby placing the central opening in communication with the packer through the inflation passageway. A slidable control valve is disposed in the inflation passageway and is initially shearably held in an open position. Upon application of a second predetermined pressure across the valve, the valve is moved to a closed position, thus preventing overinflation of the packer and also preventing deflation thereof.

Abstract: Oil and gas are separated downhole in a free flowing well and are transmitted separately to the surface. Liquid oil is transmitted through an elongated tubing which extends into a liquid column in the bottom of the well and is anchored in a liquid production tubing string to form an annular flow space. Gas flows from a wellbore space above the column of liquid through the annular space and through a flow passage which may be formed by a side pocket mandrel into the well annulus and then to the surface. The liquid conducting tubing is secured in the tubing string and a seal point is formed by a packer above the gas flow passage formed by the side pocket mandrel. Alternative arrangements provide for a subsurface gas flow safety valve interposed in the gas flow path. The safety valve may be interposed in a cross-over body which permits flow of liquid and gas therethrough and past a seal formed between the body and the tubing string.

Abstract: A retrievable packer 10 for isolating a selected depth of a wall of a borehole. The retrievable packer is comprised of a body member 12, a cylinder 32 surrounding the upper portion of the body member 12, and a sealing member 24 cylindrically surrounding the lower portion of the body member. The cylinder 32 and the upper portion of the body member 12 work in conjunction to provide a piston action which engages the sealing member 24 and causes the sealing member 24 to establish a seal with the wall of the borehole.

Abstract: A packer valve for regulating the fluid flow rate and pressure within a fluid conduit such as a well, includes a housing, and an inflatable packer element mounted on an elongated mandrel. The inside diameter of the housing is formed with an arrangement of annular grooves which circumscribe the inflatable packer element. The inflatable packer element is adapted to adjust an annulus between the housing and the inflatable packer element to provide complete shutoff of fluid flow or to provide a tortuous flow path for fluid flow within the annulus. The tortuous flow path causes a frictional pressure loss. The amount of the pressure loss is controlled by the inflation pressure of the inflatable packer element, by the shape of the annular grooves, and by the length of the inflatable packer element.

Abstract: Preferential disconnection of a valve-actuating subassembly from a temporary abandonment safety valve and packer assembly is provided by stops which limit relative rotation between the valve-actuating subassembly within the valve along with a locking collar associated with the interconnection between the safety valve and the packer assembly so that high torque associated with rotational movement of a drill string in a highly deviated hole effects the release of the proper portion of the assembly without danger of undesirable release of other interconnections.

Abstract: A tubing conveyed straddle packer system includes two inflatable packers interconnected with each other and spaced apart to provide for isolating a wellbore space for communicating pressure fluids between a formation zone of interest and the surface through the tubing string. An electrical cable extends within the tubing string and is operable to provide control signals to electrically controlled valves for inflation and deflation of the packers and for conveying fluids between the formation zone of interest and the tubing string and between the tubing string and the wellbore above and below the straddle packer system. A logging tool is interposed in the tubing string for precisely locating the straddle packer system in the well.

Abstract: A tubular body containing a sleeve actuated safety valve is attachable to the top end of a hurricane plug. A running tool has a floating nut connection with the tubular body and a tubular extension on the running tool effects the opening of the safety valve while connected to the tubular body. After setting the hurricane plug, the running tool is disconnected from the tubular body by setdown weight, followed by rotation. A retrieving tool has an external threaded section which is threaded through an internal threaded section in the tubular body to engage the actuating sleeve for the safety valve, and effect the opening of the safety valve. Further rotation of the running tool engages the retrieving tool with the tubular body to effect the unsetting of the hurricane plug and permit the removal of the tubular body, hurricane plug and depending tool string from the well by the retrieving tool.

Abstract: A logging plug for suspension on a wireline comprises a hollow body provided with packers for sealing it to a nipple included in a tubing string, and a flow tube through which the line may slide with minimal leakage. A sliding equalizing tube in the lower position shown blocks communication across the packers. When moved upwards by striking it with a hammer or logging tool, communication is allowed via ports in the equalizing tube and in the hollow body, the annular passage around the wireline and an axial bore in the lower part of the hollow body. Any pressure differential across the packers is thus equalized, allowing the logging plug to be easily withdrawn.

Abstract: A well pump assembly suspended by a cable from the surface. The assembly includes a subsurface safety valve and a packer. The packer is hydraulically set and released.

Abstract: A device for controlling "U" tubing in the flow of a fluid such as cement in oil well casings comprises a body which is inserted in the casing towards its lower end. The body provides a passage so that cement can pass through the body and out of the end of the casing before passing up round the exterior of the casing, displacing mud in front of it. A member is mounted in the passage which normally does not impede the flow of cement through the passage. However, when the pressure differential at spaced points along the flow of cement increases beyond the predetermined level as a result of `U` tubing, the member moves to restrict severely the area of the passage. This halts `U` tubing. The member can move back to the full flow position once `U` tubing has been controlled.

Abstract: Wellbore fluid flow rates and other fluid properties may be measured by a tool which is insertable in the wellbore on the end of a tubing string and includes an instrument section and an inflatable packer disposed on the tool for inflation by conducting pressure fluid down the tubing string to the packer. A control valve disposed on the tool is hydraulically shiftable between first and second positions for conducting fluid from the tubing string to the packer and from the packer to the exterior of the tool. The valve may be actuated by fluid conducted down the tubing string. The tool includes housing parts having respective cavities for conducting wellbore fluid through a flowmeter and for containing instrument circuit enclosures disposed therein. Pressure fluid bypasses the cavities through elongated passages formed in the tool housing parts along or adjacent to the outer periphery of the housing parts. A frangible coupling is interposed in the tool between the packer and the instrument section.

Abstract: A system for controlling flow in a well conduit including a landing nipple in the well conduit and a standing valve, which after landing in the landing nipple may be retrieved or expended from the landing nipple. The standing valve permits upward flow and prevents downward flow through the landing nipple and conduit and has a resilient seal which expands into a groove in the landing nipple to provide limited resistance to upward flow moving the standing valve upwardly out of the landing nipple. Sufficient weight on the standing valve or pumping down the conduit with sufficient pressure releases a landing ring on the standing valve to retract, permitting the standing valve to be moved downwardly and expended out of the landing nipple.

Abstract: A lock system for wells which includes a landing nipple in the well tubing and two embodiments of a lock mandrel, which are sealingly engageable and releasably lockable in the landing nipple to control flow through the well tubing. One lock mandrel is closed to flow and "plugs" the landing nipple. The other lock mandrel, which will operate as a standing valve, has a through flow passage and a check valve preventing downward flow through the flow passage and lock mandrel. Both lock mandrels utilize "C" rings for locking in landing nipples and may be released for expending downwardly from landing nipples by a predetermiend downward force.

Abstract: An improved packer is provided for sealingly engaging a well casing above a pressure responsive device within a petroleum recovery well. A sleeve-like packer body interior of the packer sealing elements is provided for structurally interconnecting lower and upper sections of a tubing string, and retains a large internal diameter for passing fluids or various downhole tools through the tubing string and to the bore of the packer. A plurality of tubular passageways are provided within the packer each positioned radially between the packer body and the packer sealing elements, and each extending axially from above to below the packer sealing elements. The passageways allow for communications of a fluid pressure signal from the annulus above the set packer to the firing head of a hydraulically actuatable device below the packer.

Abstract: A retrievable bridge plug apparatus has slip segments and packing elements which are extendable to outward positions. In a cased well, the slip segments grip the casing and prevent the longitudinal movement of the bridge plug. The packing elements contact the casing to provide a seal to isolate the well interval above the bridge plug from the well interval below the bridge plug. The bridge plug is retrieved from the well by equalizing pressure and then retracting the slip segments and packing elements. Pressure is equalized by pulling up on the retrieving tool, which couples to a fishing neck at the upper end of the bridge plug. Pulling up on the fishing neck opens a valve and exposes a flow path for fluid. The slip segments, and consequently the packing elements, are prevented from retracting during the equalization of pressure by a locking device. Then, the retrieving tool is set down to lower the fishing neck. Lowering the fishing neck releases the locking device.

Abstract: A plugging apparatus for a gravel packer. The apparatus includes a plug comprising an operating mandrel slidably received in an outer mandrel. A collet is positioned on the outer mandrel. Actuation of the operating mandrel allows engagement of the collet with a threaded portion in the packer for locking the collet into such engagement. The plug is positioned in the packer and actuated to a locking position by use of a setting tool which has a portion press fit on a ring spring mounted on the operating mandrel. Once the collet is in the locked position, the setting tool may be removed from the ring spring. The plug may be retrieved by a retrieving tool which has a collet which engages the ring spring. The retrieving tool is used to actuate the operating mandrel to disengage the collet from the threaded portion of the packer and then to retrieve the plug from the packer.

Abstract: A steam generator is located downhole in a well for generating steam to cause viscous crudes to flow out adjacent walls. A packer is mounted above the steam generator. A connector box is located between the packer and the steam generator. An electrical cable extends alongside tubing into the well and into a window in the tubing located just above the packer. The cable extends through a passage in the packer and into the connector box. Feedthrough connectors in the connector box connect the power cable with lead wires extending upward from the steam generator. Heat pipes extend from the connector box upward through the packer. The heat pipes contain gas which circulates to aid in dissipating heat from the connector box.

Abstract: A packer assembly is provided suitable for multiple setting and unsetting operations in a well bore during a single trip to seal the annulus between the interior walls of the well bore and a tubing string. Thge packer is set by dropping a metal ball which plugs the passageway through the tubing string, such that tubing pressure may thereafter be increased to inflate the packer. A sleeve is axially movable within a control sub from a ball stop position to a ball release position, and has a cylindrical-shaped interior surface with a diameter only slightly greater than the ball. Collet fingers carried on the sleeve are radially movable from an inward position to an outward position to stop or release the ball as a function of the axial position of the sleeve.

Abstract: A steam generator is located downhole in a well for generating steam to cause viscous crudes to flow out adjacent wells. A packer is mounted above the steam generator. A connector box is located between the packer and the steam generator. An electrical cable extends alongside tubing into the well and into a window in the tubing located just above the packer. The cable extends through a passage in the packer and into the connector box. Feedthrough connectors in the connector box connect the power cable with lead wires extending upward from the steam generator. Cooling fluid passages in the packer allow circulation of cooling fluid from the surface to cool the components. The packer is hydraulically set by water supplied to the cooling fluid passages. A disk ruptures after the packer has been set to enable circulation of the cooling fluid.

Abstract: A pump produces through a tubing in a cased well. Gas is vented through the packer and through a valve preferably located in a side pocket mandrel in the tubing. A subsurface safety valve is positioned in the tubing below the side pocket mandrel and preferably below the packer. The safety valve is preferably of the flapper type and when the valve is closed liquid is automatically recirculated to the pump.

Abstract: A well system employs a pump to lift liquid through a primary tubing and subsurface safety valve. The tubing passes through a packer and a vent valve vents gas from the well through the packer. The power transfer means may extend through the vent valve and the vent valve may also control a cross-over in the packer for recirculation of liquid to the pump when the well is shut-in. The vent valve has associated therewith a kill valve permitting pumping of kill fluid into the well. The vent remains closed in the presence of ambient pressure up to a selected value and above this value the kill valve opens thus permitting testing of the packer with annulus pressure below the selected pressure and pump through to kill the well with pressure above the selected pressure.

Abstract: A well production system in which a submersible pump is utilized in producing the well and gas produced by the well is bypassed through a packer with a special control valve which is constructed and arranged to permit ready passage of sound waves through the valve to facilitate determining the fluid depth in the well.

Abstract: A down hole blow out preventer which can be installed at the lower end of a drill string as close as possible to the drill bit and which can isolate an unexpected producing zone in a bore hole from the rest of the hole by closing off the drill string at its lower end and closing off the annulus between the drill string and the wall of the bore hole by means of an inflatable packer. The packer can be operated when a predetermined pressure difference exists between the annulus and the mud column inside the tool.

Abstract: An improved presettable, pressure-responsive retrievable fluid control valve contains a plurality of spring housing sections having individual springs disposed therein. Each of the springs is connected in mechanical parallel with each other spring. To select the preset pressure threshold at which the valve opens in response to a column of fluid in a tubing in which the valve is disposed, the number of springs and zero to two compression spacer members are chosen for each spring. The valve also includes a bypass section having an inner bypass mandrel connected by a frangible member to an outer bypass port member. Connected to the outer bypass port member is a sealing member for seating the valve in a seating nipple of a tubing. The bypass mandrel and the outer bypass port member are normally held by the frangible member in a fixed relationship so that ports through the bypass mandrel and the outer bypass port member are axially offset in a closed, or non-fluid conducting, position.

Abstract: This application discloses apparatus in which a body means having a bore therethrough connected as part of a tubing string is packed off within a well bore, and means including a passageway in the body means by-passes the packer to connect the annulus about the tubing string above and below the packer. The packer is expanded into engagement with the well bore upon release of a means for locking it in an inoperative position, and a means for so releasing the locking means includes a piston in the passageway which in responsive to control fluid supplied through a control line in the annulus which connects with the passageway. Upon release and setting of the packer, the piston is removed from the passageway and circulation of well fluid through the connecting means between the annulus above and below the packer is controlled by a safety valve which normally closes the passageway, but which is responsive to control fluid supplied thereto through the same control line.

Abstract: A plug for coupling to the mandrel of a well packer, to convert the packer to a bridge plug, includes an equalizing valve. A fixed component of the plug is an elongated tubular member coupled to the upper end of the packer mandrel and closed at its upper end, and having longitudinally elongated ports in its side walls. The movable component of the plug includes an outer housing for receiving the upper portion of the fixed component and an inner sleeve coupled to the outer housing by means of pins extending through the elongated ports. Seals between the fixed components and the inner sleeve seal the elongated ports in the closed condition of the valve. In the open condition of the valve, ports in the inner sleeve and the outer housing communicate with the elongated ports of the fixed component. The movable component includes a fishing neck attached to the upper end of the outer housing.

Abstract: A perforating gun is suspended downhole in a cased borehole, in underlying relationship relative to a packer device, and adjacent to a hydrocarbon-bearing formation to be completed. A connecting tubing interconnects the gun with the packer device, and includes a rupture barrier therebetween which prevents debris from accumulating within a gun firing head. An upper tubing string is removably connected to the packer device and forms a passageway which extends from the surface of the earth, down through the packer, and to the gun firing head. The upper tubing string includes a seal means and an extension tube which sealingly engages the packer device and penetrates the rupture barrier to provide a passageway through which the gun can be fired from the surface of the earth. This combination of elements prevents malfunction of the gun when the tool is left downhole for an appreciable length of time.

Abstract: A packer actuated vent assembly comprising an outer barrel attached to a packer body, and a mandrel extension attached to the lower end of the mandrel of the packer. A valve means on the mandrel extension has a slidable valve element which slidably engages a medial portion of the outer peripheral surface of the mandrel and normally is in the opened position. The valve element has a boss thereon which engages a shoulder on the barrel and is thereby moved from the opened to the closed position when the packer mandrel, and therefore the mandrel extension, is properly manipulated to seat the packer. This combination of elements enables a tubing string to be run downhole into a borehole with the tubing string in the open configuration, so that fluid contained within the annulus flows through the opened valve means into the tubing string, thereby balancing the fluid pressure on either side of the tubing string; and when the packer is set, the interior of the tubing string is isolated from the borehole annulus.

Abstract: An expendable plug assembly of the type adapted to be received within the bore of a well packer is shown having a shear sleeve and a plug body initially received within the shear sleeve interior. The plug body has a closed end for preventing flow of well fluid through the well packer when the plug body is in place within the shear sleeve. A lock ring is provided for releasably supporting the plug body within the shear sleeve interior. A collet body mounted about the plug body has a collet extension at one end thereof and a plurality of collet fingers at the opposite end thereof. The collet fingers are selectively engagable within the well packer bore to fix the plug assembly within the bore. Shear screws are provided for releasably connecting the collet extension to the shear sleeve. The shear screws are severable by downward movement of the shear sleeve relative to the collet extension.

Abstract: A subsurface safety valve for use in subterranean oil and gas well which is actuated by pressure fluctuations in the tubing-casing annulus is disclosed. The safety valve assembly consists of a safety valve mounted in a packer which is actuated by a subsurface control located above the packer. Annulus pressure variations are controlled by a surface unit. The subsurface control utilizes a reference pressure chamber in which the pressure is initially adjustable to compensate for hydrostatic pressure in the annulus. Leakage of the gas in a dome pressure chamber in the subsurface control is impeded by the presence of a barrier fluid impervious to the passage of gas therethrough, with the barrier fluid being maintained at a higher pressure than the reference pressure in the dome charged chamber.

Abstract: A well logging tool, for use within a well borehole having a flowing fluid therein, has a selective bypass means for directing a portion of the flowing fluid away from the housing of the well logging tool upon the flowing fluid exerting a predetermined pressure force upon a packer, whereby damage to the packer from increased pressure forces is minimized and flow characteristics of a fluid flowing at widely varying flow rates may be measured.

Abstract: An apparatus, such as a shear-out safety joint, which is incorporated in a subterranean well tubing string for separating or severing the tubing string when subjected to excessive loads is disclosed. The shear-out safety joint is used with a safety valve and by providing a prescribed failure point will ensure that the safety valve remains intact. The apparatus includes inner and outer telescoping members which can separate when the tubing above and below the joint moves in opposite directions. A shear ring connecting the two telescoping members will shear when a predetermined load is applied. The joint also has a second releasable connecting member extending through the inner telescoping member and engaging the outer telescoping member which will support a load greater than that which can be carried by the shear ring. A longitudinally shiftable member, movable within a recess, holds the second connecting member in engagement but disengages the second connecting member when moved to a second position.

Abstract: A method and apparatus for locating, isolating and treating a section of a formation located downhole in a well bore by analyzing the formation for location of the section to be treated and isolating the section to be treated, and subjecting the isolated section with treating fluid with a single-type or straddle-type expandable packer assembly. The treating fluid is fed downhole to the packer assembly through a flexible conduit which is paid-off from a reel located above ground from a mobile unit. The radially expandable packer elements of the straddle packer assembly are independently expanded and contracted with the application of positive expanding and contracting forces applied thereto through remotely located controls above ground. The packer assembly may also include a formation sensing unit for sensing downhole fluid-bearing strata while the packer assembly is being lowered.

Abstract: A retrievable plug having an improved dog locking sleeve and having adjustable dog locking pins and pin sleeves retaining the dog locking sleeve within the packer mandrel.

Abstract: In accordance with an illustrative embodiment of the present invention, a pressure equalizing and packer deflating valve apparatus useful in an inflatable packer straddle testing system included telescopically arranged mandrel and housing member defining test and inflation passages, first valve means for communicating the test passage with the well annulus when said members are extended to maintain pressure equalization as the packer elements are inflated, second valve means for communicating the inflation passage with the well annulus when the members are extended to enable packer element deflation; and third valve means that can be shifted in response to pump outlet pressure when said members are extended to a position preventing packer element deflation even though said second valve means is open. As said members are retracted, the third valve means is shifted to a position closing the inflation passage to maintain the inflation pressure therein.

Abstract: A hanger and valve assembly which can be employed as a safety valve assembly to close both the production tubing and the tubing-casing annulus in a subterranean well is disclosed. The assembly includes a hydraulically activated, mechanically locked hanger which has slip anchoring members engaging the casing or, exterior conduit for preventing movement in both longitudinal directions. The hanger also has annular packing elements to seal the tubing-casing annulus. An annulus safety valve member employing a longitudinally recessed resilient seal member can be mounted in a landing nipple mounted in the hanger. By recessing the seal it is protected from the turbulent flow through the valve. A second shuttle located in the landing nipple is employed in conjunction with the first annulus safety valve to permit flow in one direction while metering flow in the opposite direction.

Abstract: A retrievable plug having a dog locking sleeve which has a specially contoured outer surface to more closely fit within the packer mandrel and increased axial length to limit movement of the dog locking sleeve within the plug thereby eliminating binding of the dog locking sleeve within the plug mandrel during actuation of the plug body for the removal of the plug body from the member in which it is installed.

Abstract: An improved reusable plug for sealing hollow cylindrical members, such as the jacket legs, pile sleeves, piling, conductor pipes or other similar members of offshore structures, wherein the plug includes an improved packer mandrel and improved dog locking sleeve assembly.

Abstract: A method for protecting a well formation during gravel packing in which a back pressure valve is held off of its seat while gravel is being placed in the well, is automatically closed as the wash pipe is removed from the screen and in which the valve is returned to open position by a force exerted from above, either hydraulic or mechanical.A valve is held open by a prop-out which is removable to permit the valve to swing to closed position and thereafter the valve is again opened in response to mechanical or hydraulic force from above.

Abstract: A retrievable plug having a dog locking sleeve which has extensions thereon to increase the effective axial length thereof to eliminate binding of the dog locking sleeve within the plug mandrel during actuation of the plug body for the removal of the plug body from the member in which it is installed.