Abstract: A reciprocating full flow tester valve is provided with a shock absorber and tolerance adjustment device for absorbing an impact between a power mandrel of the tool and an operating assembly of the tool. An improved hydraulic impedance system is also provided for providing a time delay in telescopingly collapsing movement of the tool when weight is set down on the tool to open the tester valve.

Abstract: A fluid flow control valve having an adjustable opening pressure and using expendable components therein for use in pumping highly abrasive fluids therethrough.

Abstract: In a subterranean well having a production tubing string outwardly circumscribed by a brine-filled casing annulus, a specially designed combination casing pressure relief and kill valve is supported within a side pocket mandrel installed in the production tubing, the valve having inlet ports communicated with the casing annulus. During an initial production phase of the well, when the casing annulus/production tubing pressure differential reaches a first pressure differential set point of the valve due to a brine temperature increase, a pressure relief portion of the valve opens to admit a relatively low flow rate of annulus brine to the tubing string, thereby relieving the annulus pressure, and then closes to reseal the annulus. When it later becomes necessary to temporarily kill the well, kill fluid is pumped into the casing annulus. As the annulus pressure increases, the first valve set point is reached and the pressure relief portion of the valve opens.

Abstract: A safety valve landing nipple selectively provides a pin for closing communication in the bore between the first control line and the safety valve control line so that communication between the first control line and an insert safety valve in the landing nipple housing is achieved by use of a rotary member. A rotary shifting tool is used to rotate the rotary member so that a cam sleeve pushes a poppet pin to form a metal to metal seal with a fitting adaptor connecting the first control line and the safety valve control line so as to provide communication between the surface control line and the internal bore of the landing nipple.

Abstract: A pressure sensitive valve for a fluid-actuated percussive drill includes passageways for fluid flow to expose a valve surface to a burst of short-interval, high pressure fluid from a drive chamber to cause early closing of the valve.

Abstract: An apparatus is provided for use in a wellbore for reducing the effects of pressure differential forces which act on settable wellbore tools suspended therein. The apparatus operates to provide a bypass fluid flow path through the settable wellbore tool for directing wellbore fluid through the settable wellbore tool in response to pressure differentials developed across the settable wellbore tool during outward radial expansion of the tool. The apparatus further includes mechanisms for maintaining the bypass fluid flow path in an open condition during at least an expansion mode of operation to diminish the effects of pressure differential developed across the settable wellbore tool. The apparatus also includes mechanisms for closing the bypass fluid flow path once a setting mode of operation is obtained.

Abstract: A well pressure monitoring system in which a hydrocarbon fluid is being produced through a Christmas tree or similar flow controller apparatus. Well pressure is transmitted through a tap-off communicated to a pressure sensor. The pressure is thereafter transmitted to a base or control station. To avoid a major uncontrolled flow of the hydrocarbon from the well in the event of inadvertent breakage or accident to the monitoring system, an excess flow control valve is positioned between the well flow and the pressure sensor. The excess flow valve functions to cut off fluid flow, but is provided with a vent passage in the valve actuator through which a minimal amount of the hydrocarbon can escape. When the damage to the monitoring system has been overcome, the vent passage will allow a downstream pressure build-up in the closed system, thus permitting a biasing spring to automatically reset the valve to open and operable position, thereby stabilizing the pressure acting on the actuator.

Abstract: A downhole, inline well safety shutoff valve has a spring-loaded, normally closed flapper shutoff valve element that may be opened by a downwardly driven movement of an operator tube coaxially and slidably disposed within the tubing string bore. The operator tube is vertically driven by a rod structure disposed in an offset passageway in the safety valve housing and operated by fluid control pressure transmitted thereto from the surface. To substantially preclude undesirable communication in the passageway between pressurized production fluid and pressurized rod control fluid, the rod structure is slidably carried within a specially designed seal structure including a cylindrical sleeve coaxially received in the offset passageway, and a sealing ring captively retained between the top end of the sleeve and an annular ledge formed in the passageway. The sealing ring functions to create a dynamic seal around the rod side surface and a static seal between the ring and the interior passageway surface.

Abstract: Once a new oil well has been drilled and cased, a test string is set in place for the purpose of evaluating the production potential of the chosen formation. One way of controlling the operation of the various tools included in the downhole test string, including the opening and closing of the downhole valve itself, is by changes in the pressure differential between the tubing and the annular space which surrounds it in the well, but this requires the provision and maintenance of a fixed "reference" pressure within the tool, and a convenient such pressure is the hydrostatic (annulus) pressure experienced by the string after it has been lowered down the well bore and set into the packer.

Abstract: A hydraulic system is provided for an electronically controlled downhole testing tool. The tool operates on a pressure differential between the well annulus and a substantially atmospheric pressure dump chamber defined in the tool. Power passages communicate a power piston with the well annulus and the dump chamber. Normally closed electric solenoid control valves are disposed directly in the power passages to control fluid flow therethrough. A pressure regulator regulates the pressure differential across the electric solenoid control valves.

Abstract: A travelling valve assembly utilizing a length of tubing, longer than the production screen, positioned at the end of a wash pipe and lowered into the tubing bore so that the lower end of the tubing is a depth below the production screen. When gravel packing is concluded, the tubing is then placed in position by raising the wash pipe and tubing to the upper seal bore. The wash pipe is then sheared from the tubing assembly. The tubing includes seals at each end, which seat in respective seal bores, for sealing off above and below the production screen. There is further provided a valving mechanism, such as a sliding door valve which is operable from the surface between open and closed positions. While the valving mechanism is closed, the production flow is prevented; however, upon opening the valve through a wire line or shifting tool, production flows through the sliding door valve and up to the surface through the tubing.

Abstract: A differential pressure actuating system for downhole tools provides endless operation by the use of the differential pressure between two isolated zones of a well as a power source for the tool. That differential pressure is applied across a power transfer element to operate the downhole tool.

Abstract: A downhole shut-in tool includes in one aspect a pilot valve which when opened places a differential pressure across a piston which in turn operably engages a shut-in valve element to close the shut-in tool. An electronic timer assembly and electric drive motor are provided for controlling the action of the pilot valve. The drive motor is controlled by a load sensor which senses that the motor has stalled when an actuator engages a movement limiting abutment. In another aspect a pilot valve is provided which can selectively communicate the pressure differential across the piston so as to repeatedly open and close the shut-in valve element. Efficient methods of drawdown and buildup testing using such an automated multiple operating shut-in tool are provided. Associated automated sampling tools are also disclosed.

Abstract: A downhole, inline well safety shutoff valve has a spring-loaded, normally closed flapper shutoff valve element that may be opened by a downwardly driven movement of an operator tube coaxially and slidably disposed within the tubing string bore. The operator tube is vertically driven by a rod structure disposed in an offset passageway in the safety valve housing and operated by fluid control pressure transmitted thereto from the surface. To substantially preclude undesirable communication in the passageway between pressurized production fluid and pressurized rod control fluid, the rod structure is slidably carried within a specially designed seal structure including a cylindrical sleeve coaxially received in the offset passageway, and a sealing ring captively retained between the top end of the sleeve and an annular ledge formed in the passageway. The sealing ring functions to create a dynamic seal around the rod side surface and a static seal between the ring and the interior passageway surface.

Abstract: Disclosed is a sliding sleeve valve and a selective pressure operated shifting tool engageable in the selected sleeve valve for shifting the valve sleeve between open and closed positions. The sleeve valve is connectible in a well conduit and is especially useful in highly deviated and horizontal wells. The sleeve valve has a longitudinal flow passage through, centralizers for centralizing the valve in well conduits, longitudinal flow slots on the valve body and ports connecting the flow slots and flow passage. The pressure operated shifting tool is connected to reeled tubing by a quick disconnect. The shifting tool includes an invertible shifting module which may be inverted to shift the valve sleeve to closed or open position. The shifting tool keys are locked retracted for running and on complete shifting of the sleeve are automatically released from the valve sleeve and returned to locked retracted position for retrieving.

Abstract: Disclosed is a new and novel poppet type safety valve useful in flow conduits in fluid storage well systems. The safety valve is programmable to automatically close at various predetermined ratios of production mass flow rate-ambient pressure to prevent undesirable high flow rates or uncontrolled out-flow of fluid stored in a reservoir if the flow conduit or wellhead is damaged. This safety valve is lowered into and locked and sealed in a landing nipple in the well conduit. The safety valve has a variable bias which biases the valve member toward open position and a variable flow restrictor which is automatically actuated by a sensing actuator continually sensing reservoir pressure to vary the restricted annular flow area between the valve housing and inside of the well conduit for closure at the desired flow rate. The valve element has a through flow passage with locking recesses in the flow passage into which the sensing actuator may be releasably locked.

Abstract: In the disclosed pressure operated valve, a sleeve valve controlling flow between outside and inside the valve is releasably connected in a housing when the sleeve valve is in open position. Pressure on a ball sealingly engaging the sleeve valve operates the sleeve valve from open to latched closed to disconnect positions and expends the sleeve valve from the housing.

Abstract: A pressure responsive below packer valve apparatus which allows operation of a below packer valve through application of pressure to the wellbore annulus above the packer. The valve apparatus includes a crossover located in a tool string above the packer which communicates upper annulus pressure to a conduit inside the tool string. This conduit communicates annulus pressure to a valve mechanism below the packer. A selectively releasable mechanism such as a rupture disk communicates pressure to the valve mechanism once a threshold pressure is reached, thereby facilitating operation of the valve mechanism through application of annulus pressure.

Abstract: A shifting tool, operating on a single control line, selectively shifts a sliding sleeve in a well to either an open or closed position. The tool includes two sets of shifting dogs to manipulate a sliding sleeve in either direction. The tool includes locking dogs which insure proper location of the shifting tool as well as removing the load from the supporting coil tubing.

Abstract: A hydraulically controlled apparatus responsive to changes in well annulus pressure is disclosed. The apparatus is run into a well bore intersecting an oil and gas reservoir with perforations communicating the oil and gas reservoir with the well bore. The apparatus has an associated packer to effectively seal off the perforations in the well bore. The apparatus contains a cylindrical housing with ports on the top end and bottom end, and an operating mandrel is disposed therein. A disengaging sleeve operably connected with the operating mandrel allows the ports contained on the lower portion of the cylindrical housing below the packer to be opened and closed selectively, thereby allowing communication of the reservoir pressure through the apparatus. The disengaging sleeve and operating mandrel are activated by either an increase or decrease in annulus pressure.

Abstract: There is disclosed apparatus for use in completing a well whose well bore has a substantially horizontally extending lower end into which a casing string is to be lowered, the apparatus including a tool adapted to be connected in the casing string and having a plug therein above a back pressure valve installed in the lower end of the string to form a buoyant chamber within the casing string which is filled with a low density fluid for lowering into the substantially horizontally extending lower end of the well bore.

Abstract: A tool actuator which comprises a casing containing a pipe, which is movable from a locking position to an unlocking position, under the action of a fluid pumped through the casing. When the pipe is in the locking position it locks a mandrel in an activating or deactivating position. When the pipe is in the unlocking position it does not contact the mandrel which is therefore free to move between the activating and a deactivating positions. The fluid pressure will be different for each of the positions of the pipe and mandrel and consequently their position can be monitored by monitoring the pressure of the fluid, for a given fluid flow rate.

Abstract: A travelling disc valve assembly, comprising a length of tubing lowered down a cased wellbore; a crossover tool secured to the lower end of the length of tubing; a length of wash pipe secured to the lower end of the crossover tool; a disc valve assembly secured to the wash pipe and positioned to a lower circulation position in the well bore; a disc valve secured in a bore of the assembly; in the upper portion of the assembly for shearing off the connection between the wash pipe and the disc valve assembly, when the disc valve assembly is in an upper position, providing to prevent fluid from flowing into the formation below the disc valve and to prevent production flow to the surface; and a to rupture the disc valve at a predetermined time so that the production within the formation is allowed to flow through the assembly bore to the surface.

Abstract: The invention relates to a method of testing a well, comprising the steps of:providing a pipe string with a tester valve assembly adapted to allow or prevent fluid flow from an isolated lower interval of the well into the pipe string, said tester valve assembly comprising a valve element movable between a closing and an opening position, said valve element being in a predetermined initial position;suspending from a cable inside the pipe string a measurement assembly including sensor means, and lowering said measurement assembly into engagement with valve actuating means of the tester valve assembly, the arrangement being such that said sensor means is exposed to the fluid of said interval as a result of said engagement, irrespective of the position of the valve element;exerting a succession of tensions and releases on the cable to operate said valve actuating means, said succession effecting successive changes in the position of the valve element, while measuring by said sensor means the modifications of flui

Abstract: An actuator for actuating a downhole mechanism in a well utilizes increased annular pressure in one instance, and a control line pressure in a second instance. The actuator has an actuating chamber in which an actuating piston moves. The actuating piston communicates with the annulus pressure on one side and with pressure in an intensified pressure chamber on the other side. A control valve locates in a control passage leading from the intensified pressure chamber to the actuator piston. A vent valve locates in a vent passage that leads from the actuator piston to the annulus. The vent valve will close when pressure in the intensified pressure chamber exceeds the annulus pressure by a selected amount. Then, at a selected higher pressure, the control valve will open, allowing the pressure in the intensified pressure chamber to act on the actuator piston. A differential area piston will supply the increased pressure in the intensified pressure chamber from the annulus when the actuator is used with a test tool.

Abstract: A differential pressure actuating system for downhole tools provides endless operation by the use of the differential pressure between two isolated zones of a well as a power source for the tool. That differential pressure is applied across a power transfer element to operate the downhole tool.

Abstract: A safety valve for use in a well conduit which is automatically actuated to close when production flow impingement on a retrievable flow choke in the safety valve operating tube is sufficient. The safety valve utilizes all metal to metal seals and includes a unique roller detent mechanism, which releasably positions the operating tube in valve open position and provides snap closure of the valve. The operating tube has internal locking recesses and a metal seat. A flow choke of the size to cause safety valve closure at a selected flow rate is connected on a lock mandrel having a metal sealing surface. The lock mandrel with choke is lowered into the safety valve and operated to seal on the metal seat and lock in the locking recesses. When it is desirable to change the choke size, the lock mandrel is retrieved from the safety valve to surface.

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: An annulus pressure responsive tool is temporarily deactivated so as to no longer be responsive to changes in well annulus pressure. The tool includes a tool housing with a power piston slidably disposed in the housing. A first pressure conducting passage in the housing communicates the well annulus to one side of the power piston. A reference pressure means is disposed in the housing for providing pressure to the second side of the power piston. Thus, a pressure differential is created across the power piston. Also, a selectively operable temporary deactivating means is provided so that the power piston is no longer responsive to changes in the well annulus pressure.

Abstract: A circulating valve for use in oil field operations which is pressure operated without use of a wireline tool. The valve has a sleeve assembly with telescopically joined sleeve members normally closing off a circulation port in a mandrel. A pressure differential is utilized to shift the joined sleeve members to an unjoined condition opening the circulation ports. A second pressure differential is utilized to rejoin the sleeve members and close off the circulation ports. The sleeve members are independently shear pinned to the mandrel.

Abstract: A stacked water injection regulator for controlling liquid flow into a subterranean formation having a bore hole therein, including having a mandrel having a single side pocket, a multiplicity of longitudinally aligned and physically connected liquid flow regulators and a single latching means for securing regulators in the pocket. The mandrel and the regulators together form at least two axially opposite flow paths from the interior of the bore hole to common injection ports at the exterior of the mandrel in fluid communication with the subterranean formation.

Abstract: A subsurface well tool having a hydraulic piston and cylinder assembly actuator which is adapted to be connected to and controlled by a hydraulic control line extending to the well surface. The assembly has a cross-sectional area exposed to the hydraulic control fluid which increases in one direction of movement of the assembly and decreases in the opposite direction for reducing surface operating pressure problems. Preferably, one of the piston and cylinder includes a tapered surface, and includes a flexible seal between the piston and cylinder.

Abstract: A retrievable fluid control valve apparatus is provided for controlling fluid flow into a tubing string of a well. The control valve apparatus includes a housing. The housing includes a seal for sealingly engaging a landing nipple of the tubing string. A flow passage is defined through the housing and has an open end defined in the housing below the seal. A flow port is defined through the housing and communicates the flow passage with an exterior of the housing above the seal. A flow valve is disposed in the housing and is movable between a closed position wherein the flow passage is closed and an open position wherein the flow passage is open. A spring is associated with the flow valve for biasing the flow valve toward its closed position. A differential area piston is associated with the flow valve for overcoming the force of the spring and moving the flow valve to its open position when a fluid pressure in the tubing string exterior of the housing exceeds a predetermined value.

Abstract: A subsurface valve-actuator combination for well production tubing is described. The valve is urged to closed position but held open by a battery-operated latch of the actuator. A receiver-relay in the battery-actuator circuit maintains a switch closed to permit the latch to be energized as long as the receiver-relay receives an electromagnetic signal transmitted from the earth's surface. The latch is deenergized upon interruption of the signal and/or if the battery power is insufficient to energize the same.

Abstract: An apparatus for setting and retrieving a bridge plug of the type which may be passed through a small diameter tubing, and may be sealed against a relatively large diameter casing by pressured fluid to inflate an elastomeric packing element carried by the bridge plug. The running tool is engagable with a valve housing by a J-slot connection and an axially shiftable, pressure balanced valve plug cooperates with the valve housing to open or close the fluid passageway therethrough extending to the inflatable elastomeric packing element. Upward movement of the running tool followed by left hand rotation effects the closing movement of the valve plug and the disengagement of the running tool. Downward movement of the running tool, while engaged with the valve housing, effects an opening of the plug valve.

Abstract: The invention relates to a tool having a valve (3c, 4c) for closing the tubing (100) of a well into which the tool has been placed. The valve member (4c) is controlled by means of a traction cable (17) via a hydraulic mechanism having two piston-and-cylinder assemblies (4b, 5e, 45; 1g, 4a, 41) which reduce the force applied on the valve member (4c) by the pressure of the fluid in the well and which amplify the force (f) applied thereto by the cable (17) in order to open said valve member.

Abstract: An apparatus for closing a reverse circulation passage and opening a crossover fluid passage in a gravel packing service tool which sets a well packer comprises a closure means for closing the reverse circulation passage and an opening means for opening the crossover fluid passage in response to an axial lifting force on the service tool.

Abstract: A subsurface well safety valve having a curved flapper closure member and method making. The curved flapper has a concave sealing surface coacting with a valve seat. A flow tube has a lower end contoured to the flapper sealing surface. A flapper can be made out of a tubular member in which the inside has been honed providing a flapper with a concave surface which forms a sealing surface.

Abstract: A well testing tool includes a plurality of valves, a plurality of well tool control systems connected, respectively, to the plurality of valves, and an electronics section connected to the plurality of well tool control systems for energizing one of the control systems thereby opening or closing a valve associated with the one control system when the electronics section of the tool detects the existance of an input stimulus transmitted downhole by an operator at the well surface. The operator need only know the particular input stimulus to transmit for a particular valve and need not know how many well tools are disposed downhole or in which tool a particular valve is disposed. The opening or closing of a particular valve is accomplished independantly of any other valves disposed in the tool.

Abstract: In the representative embodiment of the new and improved well bore apparatus disclosed herein, a test valve is arranged to be coupled in a pipe string for positioning in a well bore. When the test valve is arranged to be selectively operated by changes in the well annulus pressure, the apparatus of the present invention includes a first normally-open pressure reference valve that may be operated to trap well annulus pressure in a chamber on the tool body to provide a reference pressure that permits the operation of the pressure-controlled test valve. The apparatus of the invention may include a second normally-open valve which is coupled to the first valve and is operated for controlling communication through a bypass passage between the interior and exterior of the tool body. An annulus pressure responsive actuator piston coupled to the first and second valves is operated by opening a rupture disc to communicate the well annulus pressure to the actuator piston.

Abstract: A well surging system having pressure actuated ball valves and a mechanical actuating backup for the upper of said ball valves. The apparatus comprises a valve assembly portion containing the upper and lower ball valves which may be independently pressure actuated. The valve assembly portion also includes an extension portion having an extension mandrel therein connected to an upper ball valve actuator. The lower ball valve is opened by increasing the pressure in the well annulus around the valve assembly portion with respect to a flow bore therethrough. The upper ball valve is similarly pressure actuated. In the event that the upper ball valve pressure actuation is fully or partially unsuccessful, a probe assembly portion may be lowered on a wireline into the extension portion adjacent to the valve assembly portion. The probe assembly portion is adapted for releasable engagement with a lug extending inwardly from the extension mandrel.

Abstract: An improved subsurface safety valve has a flapper plate which is held open by an operator tube, and which can be closed rapidly during high flow operating conditions without damage to the flapper plate or to the operator tube. The operator tube is telescopically coupled within a tubular piston. Retraction of the operator tube relative to the piston is yieldably opposed by a compression wave spring which is interposed between the operator tube and the piston. Telescoping retraction of the operator tube within the piston is limited by engagement of the operator tube against an internal shoulder of the piston. Damage to the flapper closure plate, pivot pin and operator tube is avoided by effectively decoupling the operator tube from the inertia load presented by the hydraulic piston and column of hydraulic control fluid.

Abstract: A side entry sub logging system has features for removing the cable should the drill pipe become stuck. A release sub is connected between the drill pipe and the side entry sub. A mandrel is carried in the side entry sub and extends into the release sub. Logging cable which passes through the side entry sub sidewall passage also passes through a passage in the mandrel. The mandrel will move between upper and lower positions. The connection between the side entry and the release sub will release when contacted by the mandrel in the lower position. This enables the side entry sub to be pulled straight upward, bringing along with it the cable. A plug dropped into the drill pipe from the surface blocks the passage through the mandrel, enabling fluid pressure to be applied to push the mandrel downwardly to actuate the connection between the release sub and the side entry sub.

Abstract: A hydraulic control system for controlling a retainer valve in an underwater well test system. The control system is contained in a housing in the test string above the retainer valve. The control system and valve are operated by a surface control manifold via control conduits extending between the manifold and control system housing. The system provides opening and closing and very quick closure of the retainer valve by eliminating the requirement for closing pressure to be conducted through a long conduit from surface and by utilizing well pressure to close the valve and lock the valve closed. One embodiment of the control system requires a pressure pulse from surface to start quick retainer valve closure. Another embodiment of the control system monitors control conduits for loss of pressure while the retainer valve is open and automatically closes the valve on loss of control pressure.

Abstract: A safety valve where weight and length and consequently the cost is reduced to a minimum. A longitudinally moveable flow tube controls the movement of a valve closure element, a biasing mechanism biases the tube to a closed position, and a piston and cylinder assembly engages and moves the flow tube. A portion of the assembly is positioned beside and longitudinally overlaps the biasing mechanism for allowing the length of the valve to be reduced.

Abstract: In accordance with illustrative embodiments disclosed herein, a formation testing tool suspended in a well on a pipe string includes a valve actuator control system which responds to a command signal having a certain signature. The command signal is applied at the surface to the well annulus, and includes a series of two or more low level pressure pulses which are detected at the downhole tool, each pressure pulse having, for example, a certain peak value which lasts for a certain time. On detection of the command signal, a control system within the testing tool permits selective application of hydrostatic pressure which forces the valve actuator to shift from one position to another, thereby to open or close an associated valve element.

Abstract: A well testing apparatus includes a housing having a formation fluid flow passage. A sliding sleeve tester valve is reciprocably disposed in the housing. A probe separable from the housing and constructed to be received coaxially within the sliding sleeve tester valve has a probe passage defined therethrough for communicating the formation fluid flow passage with a measuring device carried on the probe. A probe valve is also disposed in the housing and is constructed to receive a lower end of the probe. A releasable connector operably connects the probe and the sliding sleeve tester valve so that the sliding sleeve tester valve is moved between its open and closed positions in response to reciprocal movement of the probe relative to the housing. The tester valve can be operated an indefinite number of times, and whenever desired the probe can be disconnected from the tester valve in response to an appropriately timed reciprocable motion of the probe.

Abstract: Means for lifting formation fluid to the surface in a drill stem test. The drill string has first openings allowing entry of formation fluid and upwardly spaced second openings which are normally closed by a sleeve slidably mounted on the drill string. Fluid pressure from within the drill string impinges on a transverse surface of the sleeve and forces it down, allowing treatment fluid to enter the drill string from the annulus between the drill string and the well bore. A jet pump comprised of a flow constriction creating a venturi effect causes treatment fluid to accelerate upwardly in the drill string, the circulation of the treatment fluid drawing the formation fluid to the surface. The second openings covered by the sleeve include the fluid crossover of the jet pump. A standing valve in the drill string between the first and second openings allows down hole shut-in and pressure build-up tests.

Abstract: A subsurface well safety valve having two control lines which run from the well surface to first and second piston and cylinder assemblies for controlling the valve. The first of the assemblies is connected to a flow tube for operating the valve but the second assembly is disconnected from the flow tube. When a failure occurs in the primary control system, the first assembly is disconnected from the flow tube and the second piston and cylinder assembly is connected to the flow tube to operate the safety valve.

Abstract: A sleeve type valve useful in a well tubing string for controlling flow between the valve interior and exterior. An internal pressure balanced sleeve is releasably positioned to the valve body closing a flow port in the valve body wall to flow. The valve has an external pressure unbalanced sleeve also releasably positioned to close the port to flow. When the internal sleeve is moved to a position opening the port to flow, pressure may be increased in the valve interior to act through the port on the unbalanced sleeve, moving this sleeve to a position also opening the port to flow and permitting flow between the valve interior and exterior. The body has profiled grooving and a seal bore above the port and a seal bore below the port in which a locking mandrel may lock and seal, reclosing the port to flow.