Abstract: There is herein defined a control apparatus operable to control the opening and closing of downhole flow control devices. The apparatus includes first and second indexing modules, which are arranged in fluid communication with a respective downhole control device. Each of the modules includes two inlet ports and two outlet ports, where the inlet ports are each in fluid communication with one of two control lines. The first module is operable to open and close a first downhole control device on application of fluid pressure through the first control line and the second module is operable to open and close a second downhole control device on application of fluid pressure through the second control line.

Abstract: A downhole isolation valve for testing the integrity of a tubular within a wellbore includes a tubular body (12) with an axial through bore (14) having a reduced diameter portion (29) defining a valve seat (16) and a ledge (17); an inner sleeve (18), with a closed end (22) configured to seal within the valve seat, a shoulder (28) spaced from that closed end, and a radial outlet (24) positioned between the shoulder and the closed end; wherein in use the inner sleeve is selectively moveable within the bore at a predetermined pressure between a closed position, in which there is no flowpath through the bore, and an open position, in which the closed end is positioned beyond the valve seat to expose the radial outlet to the through bore beyond the valve seat and provide a flowpath through the bore of the outer tubular body.

Abstract: A system for fracturing a subterranean formation includes a housing having one or more radially directed ports therein. A valve disposed within the housing proximate the one or more ports. A seat member interactive with the valve to rapidly prevent or substantially retard fluid flow therethrough. A method for initiating a fracture in a subterranean formation is included.

Abstract: A barrier valve has an equalizing feature for the ball or plug when in the closed position before it is opened. A hydraulic open and a close line are connected to a housing so that they can move a piston in opposed directions. The piston ends are sealed and the exterior of the piston is tapered to push one or more bypass valves open to connect tubing pressure across the ball when ramped off its seat. Pressure on the main hydraulic line to close the ball reverses the piston movement and allows a spring bias to close the bypass valve or valves. The equalizing system can be integrated into the barrier valve housing or can be separate as a retrofit.

Abstract: The present invention is embodied in systems and methods for mitigating temperature-related pressure buildup in the trapped annulus of an oil or gas well, wherein such systems and methods employ production and/or tieback casing having one or more pressure mitigating chambers, and wherein such chambers make use of pistons, valves, and burst disks to mitigate pressure increases within the annulus.

Abstract: An equalizing valve for a flapper in a subsurface safety valve has a valve member disposed in a passage in the flapper that is made of a material that changes shape when subjected to a stimulus such as heat, for example. In one configuration, the valve member closes off the passage and in another flow past or through the valve member defines the open position allowing pressure to equalize across the closed flapper. Other valve applications are envisioned for downhole use. The stimulus can come from applied electrical current that causes sufficient heating to have the valve member alter its shape. Mechanical assists to the shape altering can be provided which can also optionally be made of shape changing materials. Biasing into a sealed position is envisioned.

Abstract: Disclosed herein is a safety valve with a chemical injection configuration. The device includes a hydraulic fluid pressure operated piston at the housing. The device further includes a flow tube in operable communication with the piston and a chemical injection configuration disposed within the housing. Further disclosed herein is a method of maintaining the operation of a safety valve by injecting chemical fluid through a configuration within the safety valve. Still further disclosed herein is check valve. The check valve includes a seal, a dart having a closed head and sealable against the seal, one or more flutes on the dart, and a spring applying a biasing force to the dart to a sealing position, that force being overcomeable by a fluid pressure acting in a direction opposing the spring force.

Abstract: A valve assembly for regulating fluid flow in a horizontal wellbore. A housing can be coupled to a production tubular. A chamber is defined within the housing and can be in fluid communication through a flow channel with an inner annulus formed adjacent the wellbore. A piston and a biasing member can be disposed within the chamber, where the biasing member biases the piston into a first position. A flowpath is defined within the housing and communicable with both the production tubular and the inner annulus. The flowpath can include one or more nozzles disposed therein, and the piston can be configured to move between the first position allowing fluid flow through the flowpath to the production tubular and a second position preventing fluid flow to the production tubular.

Abstract: A method for drilling a wellbore includes drilling the wellbore by advancing the tubular string longitudinally into the wellbore; stopping drilling by holding the tubular string longitudinally stationary; adding a tubular joint or stand of joints to the tubular string while injecting drilling fluid into a side port of the tubular string, rotating the tubular string, and holding the tubular string longitudinally stationary; and resuming drilling of the wellbore after adding the joint or stand.

Abstract: A pressure equalizing system allows flow past an upper seal on a movable member downhole that in turn allows pressure to be delivered from uphole into what had previously been an isolated low pressure zone. The pressure differential across the member is equalized before attempting to move the member into another position. In the preferred embodiment the member is a ball in a ball valve for subterranean use.

Abstract: Well tools are provided which although pressure responsive, may be maintained by a hydraulic lockout in a nonresponsive condition until a threshold actuation step is performed. This lockout may be achieved by a hydraulic mechanism which controls the rate at which pressure is transmitted to a fluid spring during periods of increased pressure at the pressure source. When the tool is desired to be responsive to pressure cycles, a valve may be opened by established a differential between the pressure in the fluid spring and the pressure source. Communication of pressure in the fluid spring to a movable mandrel will then allow operation of the well tool in response to pressure cycles at the pressure source in accordance with the established design of the well tool.

Abstract: A downhole valve that operates on turning of a member having a passage through it with a control system also features a passage from above an uphole seat for the member which communicates to the isolated passage within the member when the valve is closed. The passage features a check valve assembly that preferably has redundant sealing features and filters to prevent debris entry. Pressure applied from above the closed member gets through the check valve assembly to equalize the higher pressure below the ball with the pressure raised in the ball from pressure application at the surface. Removal of the applied pressure reseats the check valve or valves to allow the hydraulic system to rotate the member while the member is no longer subject to a high differential pressure.

Abstract: A pressure equalizing tool can be run into a downhole tool on wireline or coiled tubing preferably and temporarily secured before being actuated to separate two components in a downhole tool that are in a sealing relation but are configured to be temporarily movable so as to allow pressure equalization before the downhole component is actuated. Once pressure is equalized the equalizing tool is released, usually with an applied pick up force and the downhole tool being equalized as to differential pressure can be operated with the preexisting actuation parts that are on the downhole tool. In a preferred embodiment the downhole tool is a ball valve and the equalizing tool is temporarily secured to the ball valve housing to temporarily part the ball from the uphole seat to equalize an annular space around the ball with tubing pressure. The ball is allowed to go back to contact with the seat when the equalizing tool is released and removed from the tubing.

Abstract: A backpressure valve. The backpressure valve may be configured to maintain a substantially controlled pressure in bottom hole assembly while simultaneously being compatible with a pressure pulse tool downhole thereof. The backpressure valve includes pressure generating capacity below its internal valve assembly so as to avoid the tendency of the assembly to throttle open and closed. Furthermore, the pressure generation is achieved in a manner avoiding cavitation. As a result, once the backpressure valve is opened, the pressure pulse tool is able to reliably communicate with surface equipment at the oilfield.

Abstract: A method for positional control of an actuator includes applying pressure to both an input line and an output line connected to the actuator and then releasing a predetermined volume of fluid from the output line, thereby displacing a piston of the actuator a corresponding predetermined distance. A system for positional control of an actuator includes the actuator included in a well tool positioned in a well; the input line connected to the actuator and extending to a remote location; the output line connected to the actuator and extending to the remote location; and a fluid volume measurement device connected to the output line at the remote location. The fluid volume measurement device is operative to meter the predetermined volume of fluid from the output line.

Abstract: A method for maintaining pressure in a wellbore during drilling operations is disclosed. The method includes the steps of providing fluid from a reservoir through a drill string, circulating the fluid from the drill string to an annulus between the drill string and the wellbore, isolating pressure in the annulus, measuring pressure in the annulus, calculating a set point backpressure, applying back pressure to the annulus based on the set point back pressure, diverting fluid from the annulus to a controllable choke, controllably bleeding off pressurized fluid from the annulus, separating solids from the fluid, and directing the fluid back to the reservoir. An apparatus for maintaining pressure in a wellbore during drilling operations that includes an adjustable choke for controllably bleeding off pressurized fluid from the wellbore annulus, a backpressure pump for applying a calculated set point backpressure, and a processor for controlling the adjustable choke and backpressure pump is also disclosed.

Abstract: A series of screens with restrictors to equalize flow through base pipe perforations downstream or upstream of each restrictor features a valve member in the openings so that the screens are closed to flow for run in. Pressure can be developed within the base pipe for operation of downhole equipment below the screens such as a mud motor or in the screen liner such as a packer with no need for an internal string or wash pipe. The openings can be opened selectively when the associated equipment connected to the base pipes has been operated. The valve member can be actuated to open in a variety of ways such as applied pressure, temperature or a change in well fluid condition.

Abstract: A pressure equalizing tool can be run into a downhole tool on wireline or coiled tubing preferably and temporarily secured before being actuated to separate two components in a downhole tool that are in a sealing relation but are configured to be temporarily movable so as to allow pressure equalization before the downhole component is actuated. Once pressure is equalized the equalizing tool is released, usually with an applied pick up force and the downhole tool being equalized as to differential pressure can be operated with the preexisting actuation parts that are on the downhole tool. In a preferred embodiment the downhole tool is a ball valve and the equalizing tool is temporarily secured to the ball valve housing to temporarily part the ball from the uphole seat to equalize an annular space around the ball with tubing pressure. The ball is allowed to go back to contact with the seat when the equalizing tool is released and removed from the tubing.

Abstract: A downhole device used to divert fluid flow out of a work string into an annulus. The downhole device is activated by the movement of a plurality of pistons within the downhole device. Fluid flow through a restriction of the downhole device creates an increase in fluid pressure causing the movement of the pistons. The pistons move a flow tube between various locations within the device. In one location, the flow tube prevents fluid flow to the annulus while in another location the flow tube allows fluid flow to be diverted into the annulus. The downhole device may include a locating sleeve having a continuous j-track allowing the flow tube to be selectively retained at the various locations within the downhole device. Fluid flow through the downhole is used to cycle the device between diverting fluid flow to the annulus and forcing fluid flow down the work string.

Abstract: An embodiment of a valve that is operable from one position to another position upon relief of an applied pressure includes a housing having a bore; a valve member disposed with the housing, wherein the valve member is actuated to one position in response to a certain applied pressure and actuates toward another position upon relief of the certain applied pressure; and a relief system relieving the pressure applied to the valve member when the applied pressure falls below a selected pressure level.

Abstract: A throttle valve (10), in particular for injecting a fluid into a geological formation, is described, which comprises a valve body (10) having a piston chamber (11), an annular piston (20) having a fluid channel (21), which extends from a high-pressure side (H) to a low-pressure side (L) of the throttle valve, with the annular piston (20) being displaceable within the piston chamber (11) and the fluid channel (21) being transmissive or closed depending on the position of the annular piston (20) in the piston chamber (11), and a cover plate (12) which is provided on the high-pressure side of the valve body (10) and through which the fluid channel (21) protrudes from the high-pressure side piston chamber (11), wherein the fluid channel (21) is closed in axial direction with a sealing disk (22) which can be rested tightly on the cover plate (12) on the high-pressure side, and the fluid channel (21) has a radial throttle opening (23) adjacent to the sealing disk (22).

Abstract: A downhole valve for insertion in a production tubing string permits recirculation of fluid pumped into the casing annulus. The valve includes a cylindrical housing defining an opening, an internal mandrel disposed within the housing, defining a central bore and defining an opening, a valve between the housing and the mandrel, wherein said valve opens to allow fluid communication from the mandrel central bore to the annulus space in response to a pressure differential between the mandrel central bore and the annular space, and biasing means for biasing the valve in a closed position.

Abstract: A control system can be used with a single control line to a subsurface safety valve. The operating piston is exposed to the flow tube between two blocks with near identical seals to make the piston insensitive to tubing pressure. A control system seal is carried by the piston in the upper block and a passage between the control system seal and the tubing pressure seal in the upper block communicates to a compressible fluid reservoir in the lower block that is also isolated from tubing pressure by a tubing pressure seal. Movement of the piston compresses the fluid in the reservoir. The reservoir can also include a spring to return the piston and the flow tube to a position to close the valve. A redundant system can be actuated if the primary system fails.

Abstract: Methods and systems for operating a sliding sleeve valve or other downhole well tool that is axially shiftable among a finite number of increments between two extreme configurations such as open and closed configurations. A metering device is described having a pair of piston metering assemblies that operate in parallel fluid flow paths. The first piston metering assembly moves the sleeve of the well tool from a fully closed position to the zero position. The second piston metering assembly can be repeatedly pressurized and depressurized to meter predetermined amounts of fluid from an actuator sequentially to move the sleeve of the sleeve valve in consecutive increments toward a fully open position.

Abstract: This invention is a constant-thrust device intended for use in submerged or pressured environments based on a piston-in-cylinder arrangement in which the enclosed chamber is evacuated or gas-filled to comparatively low pressure. The invention extends to boundary envelopes of general shape of which a cylinder is a simple form and to movable boundaries between pressured and unpressured spaces of which a piston is a simple form.

Abstract: A valve apparatus. The valve apparatus is disposed within a well so that an annulus is formed between an outer portion of the valve and an inner portion of the well. In one preferred embodiment, the valve apparatus comprises an outer mandrel containing an annulus port; an inner mandrel slidably disposed within the outer mandrel, and wherein the inner mandrel contains a production and equalizing port. The valve contains a seal assembly so that pressure from the annulus is isolated from the inner portion of the inner mandrel. In one preferred embodiment, the seal assembly comprises: a first header seal; a first seal ring, abutting the header seal, for sealing with the outer portion of the inner mandrel; a follower seal abutting the seal ring; a second seal ring, abutting the follower seal, for sealing with the outer portion of the inner mandrel; a second header seal; and an equalizing seal abutting the second seal ring.

Abstract: A ball type downhole barrier valve capable of bidirectional sealing features a ball rotating on its axis to open or close with control line pressure to an actuating rod piston assembly. The ball is also shiftable to a locked open position. A cage surrounds the ball and retains opposed seats to it. The cage is made from one piece and tangential holes are drilled and tapped before the piece is longitudinally split with a wire EDM cutting technique. Fasteners to rejoin the cut halves properly space them to the original one piece internal dimension. Auxiliary tools allow determination of spacing of internal components so that a desired spring preload on the seats against the ball can be achieved. Seals on the sleeves that form ball seats help prevent leakage due to ball distortion at high differential pressures when the valve is closed.

Abstract: A tubing hanger lands in a tubular outer wellhead member and supports a string of production tubing. The tubing hanger has a production passage for communicating with the interior of the production tubing and an annulus passage for communicating with a tubing annulus on the exterior of the production tubing. An access port leads from the annulus passage to an exterior portion of the body for communicating the tubing annulus with the annulus passage. A valve stem is movable along an axis of the annulus passage between a closed position, blocking the access port, and an open position, exposing the annulus port. A pressure equalizing passage extends from the annulus passage above the valve stem to the annulus passage below the valve stem.

Abstract: Positional control of downhole actuators. A method for positional control of an actuator includes the steps of: applying pressure to both an input line and an output line connected to the actuator; and then releasing a predetermined volume of fluid from the output line, thereby displacing a piston of the actuator a corresponding predetermined distance. A system for positional control of an actuator includes the actuator included in a well tool positioned in a well; the input line connected to the actuator and extending to a remote location; the output line connected to the actuator and extending to the remote location; and a fluid volume measurement device connected to the output line at the remote location, the fluid volume measurement device being operative to meter the predetermined volume of fluid from the output line.

Abstract: The present invention generally relates to a subsurface safety valve configured to control fluid flow through a production tubing string. In one aspect, a safety valve for deployment beneath a surface of a wellbore is provided. The valve includes a control piston and a balance piston. The valve is configured to be connected to a controller at the surface by a control line so that the control piston is actuatable between a first position and a second position in response to receiving pressurized fluid from the controller through the control line. The balance piston is configured to compensate for hydrostatic pressure in the control line. The valve may have a bore therethrough and the control piston may be configured to utilize tubing pressure within the valve bore to urge the control piston towards the second position.

Abstract: A pin connector with a seal assembly using a unique wet connect assembly. The pin connector is formed from a tubular having an upper tubular portion and a lower tubular portion. The lower tubular portion has an upper tubular body and a lower tubular body with a lower tubular body face. A first pin engages the wet connect assembly. The first pin has a first pin outer surface, which can be connected to the wet connect assembly.

Abstract: A method for controlling a fluid pressure applied to a cementing plug comprises disposing the cementing plug within a casing string to define a trapped volume of fluid within the casing string, isolating a portion of the trapped volume of fluid adjacent the cementing plug to define an isolated volume of fluid, and relieving the fluid pressure within the isolated volume of fluid at a first rate sufficient to prevent damage to or inadvertent release of the cementing plug. An apparatus for relieving fluid pressure within a casing string being run into a well bore comprises at least one equalizer valve connected to a work string extending into the casing string, and a sealing device disposed above the equalizer valve to seal an annular space formed between the work string and the casing string.

Abstract: An interventionless actuator for oil well tools is described wherein the actuator comprises at least one floating piston adapted to equalize a pressure differential and lock onto an actuating member. An interventionless actuator is described that is charged to an initial energy level less than the expected at-depth well pressure and then recharged down hole to approximately the at-depth well pressure by a floating piston. At the time of desired interventionless actuation, the actuator is overcharged to a pressure greater than the at-depth well pressure, which pressure is reacted by an actuating piston to generate an actuating movement.

Abstract: A fluid loss device including a flapper and seat assembly that provide a seal on a lower flapper surface when the flapper is closed and resists pressure in either direction. The flapper and seat assembly is spring biased to contact a flapper support above the flapper to resist deformation of the flapper due to a pressure differential from below the flapper. The flapper and seat assembly may be moved by tubing pressure to release an opening prop that opens the flapper. The valve seat may include an elastomeric seal element to improve the fluid flow restriction. The flapper and seat assembly is also biased upward by a pressure differential from below to above the flapper, to thereby increase the flapper to valve seat pressure as the fluid pressure differential increases.

Abstract: A flapper valve assembly is described having an equalizing port assembly with a bleed valve member that is moveable between an open position and a closed position. The equalizing port assembly features a structural support member in the form of a retainer key that is secured to the flapper valve member both axially and radially. Additionally, a compressible spring is located between the structural support member and provides biasing force upon the valve member to urge it toward a closed position. Additionally, the flapper valve member presents a pair of raised, substantially flat actuator contact portions upon its downstream face to meet an actuating tube in a mating contact arrangement and resist material deformation that could tend to clog or block the equalizing fluid flow port.

Abstract: A method and apparatus for controlling inflation and deflation of spaced inflatable packer elements of a straddle stimulation tool within a well casing of a well. A straddle stimulation tool is positioned by tubing at a desired location within the well casing. Fluid is pumped through the tubing and tool at a rate inflating the spaced inflatable packer elements within the well casing and establishing an annulus interval. The inflation control retains pressure within the inflated packer elements and permits the flow of stimulation fluid into the annulus interval for stimulation of the formation. After completion of well stimulation, the packer element pressure control is moved to a packer equalizing position by tension applied via the tubing to equalize packer pressure with casing annulus pressure, deflating the packer elements and permitting conveyance of the straddle stimulation tool within the well casing by the tubing string.

Abstract: A valve apparatus. The valve apparatus is disposed within a well so that an annulus is formed between an outer portion of the valve and an inner portion of the well. In one preferred embodiment, the valve apparatus comprises an outer mandrel containing an annulus port; an inner mandrel slidably disposed within the outer mandrel, and wherein the inner mandrel contains a production and equalizing port. The valve contains a seal assembly so that pressure from the annulus is isolated from the inner portion of the inner mandrel. In one preferred embodiment, the seal assembly comprises: a first header seal; a first seal ring, abutting the header seal, for sealing with the outer portion of the inner mandrel; a follower seal abutting the seal ring; a second seal ring, abutting the follower seal, for sealing with the outer portion of the inner mandrel; a second header seal; and an equalizing seal abutting the second seal ring.

Abstract: Methods and apparatus for filling a tubing string as it is lowered into a subterranean hydrocarbon well. In one embodiment, an apparatus to fill a tubular with fluid in a wellbore comprises a housing defining a central bore. An aperture formed in the housing provides fluid communication between the central bore and the ambient environment of the tubing string. A piston valve slidingly disposed in the housing is selectively pressure actuatable relative to the housing to control fluid communication between the central bore and the ambient environment.

Abstract: A system and method for preventing blowouts during the deployment of a casing string into a wellbore. The system includes securing a casing coupling to a casing string and securing a retrievable check valve within the casing coupling. The retrievable check valve allows fluid from the surface to be pumped through the retrievable check valve. However, the retrievable check valve prevents upward fluid flow from the wellbore through the retrievable check valve to the surface.

Abstract: A dirty fluid valve for sealing high differential fluid pressures in a drilling environment and methods for using such a valve is disclosed. One embodiment of the valve includes a seal cartridge having several openings for directing a fluid path through the cartridge, a spring connected at one end of the seal cartridge and extending through the fluid path, and a seal member connected to the other end of the spring. The seal is actuatable between an open position and a closed position so that it covers one of the openings in the seal cartridge when it is in the closed position, thereby sealing off the fluid flow through the seal cartridge fluid path. The spring provides a pre-loading force to the seal member so that the seal member always has sufficient contact with the surfaces surrounding the opening that the seal covers.

Abstract: An equalizer valve for a flapper in an SSV has one embodiment where the plunger body is covered with a lubricious material in the bore in the flapper to counteract wear caused by off-center contact with the plunger by the flow tube. In another embodiment the flow tube and the plunger have matching angled surfaces to reduce the resultant moment of the plunger from offset contact of the flow tube. In another embodiment the flow tube contacts the plunger on center to eliminate a resultant moment, which can cause wear in the flapper bore or to the plunger.

Abstract: The ball valve assembly 10 includes a valve body 12, a ball 14, a seat ring 30, a support ring 40, and an actuator sleeve 50 surrounding the ball and axially moveable within the valve body for rotating the ball between the open position and the closed position. A plurality of seals seal with the seat ring, the actuator sleeve, the support ring, and the valve body. The actuator sleeve 50 maintains fluid pressure within the valve body. The ball, support ring and seat ring are each formed from a selective material to enhance life of the ball valve assembly. A pair of pins 80, 82 each extend in a slot within the ball and holes in the sleeve, and preferably the pair of pins and the ball rotate with respect to the sleeve as the sleeve moves axially within the valve body.

Abstract: Method and apparatus for drilling a well bore in a hydrocarbon formation using concentric drill string having an inner pipe and an outer pipe defining an annulus there between. A drilling means such as an air hammer or a rotary drill bit and driving system is provide at the lower end of the concentric drill string and drilling medium is delivered through the annulus or inner pipe for operating the drilling means to form a borehole. Drilling medium, drilling cutting and hydrocarbon are removed from the well bore by extracting the drilling medium, drilling cutting and hydrocarbon through the other of the annulus or inner pipe.

Abstract: An equalizer valve for a flapper in an SSV is disclosed. In one embodiment the plunger body is covered with a lubricious material in the bore in the flapper to counteract wear caused by off-center contact with the plunger by the flow tube. In another embodiment the flow tube and the plunger have matching angled surfaces to reduce the resultant moment of the plunger from offset contact of the flow tube. In another embodiment the flow tube contacts the plunger on center to eliminate a resultant moment, which can cause wear in the flapper bore or to the plunger.

Abstract: The invention provides an apparatus for actuating a downhole tool by utilizing a pressure differential created by fluid flowing through a conduit. The conduit is in communication with a pressure sensing line that is selectively exposable to areas of the conduit having different pressures. By exposing the pressure sensing line to a portion of the conduit having a predetermined pressure therein, the pressure sensing line cause actuation of a hydraulic tool therebelow.

Abstract: A downhole valve assembly (10) comprises a tubular body (12), and a valve comprising a valve member (18) and a fluid actuated valve control mechanism (14) adapted to be selectively actuated to move the valve member between an open and a closed configuration, for selectively allowing fluid flow through the body (12). A first hydraulic control conduit (41) is in fluid communication with the valve control mechanism (14) for permitting actuation Of the control mechanism to move the valve member (18) to the open configuration, by application of a first control fluid. A second hydraulic control conduit (41) is in fluid communication with the valve control mechanism (14) to move the valve member (18) to the closed configuration, by application of a second control fluid.

Abstract: A mudsaver valve for use in well drilling operations includes an elongated tubular main body supporting a tubular mandrel-like mudsaver closure member therein for movement between valve open and closed positions. A coil spring is disposed in the main body member and is engageable with the mudsaver closure member to bias the mudsaver closure member in a valve closed position. The mudsaver closure member includes an axial passage formed therein and ports opening from the axial passage to the exterior of the mudsaver closure member. The mudsaver closure member is engageable with an annular resilient packoff element and is pressure biased to move to an open position wherein the ports pass through the annular packoff element to allow fluid to flow through the valve.

Abstract: The hydraulic control system for operating a flow tube in a subsurface safety valve is disclosed. An isolation piston is used in conjunction with an operating control line and an engagement control line. Both control lines run from the surface. The isolation piston is spring loaded to equalize pressure across a dynamic piston to allow the flow tube to be shifted by a power spring to allow in turn the subsurface safety valve to close. Application of pressure on the engagement control line directs pressure applied through the operating control line to the top of the dynamic piston thus shifting the flow tube downwardly to open the subsurface safety valve. In an alternative embodiment, a coaxial control line directs fluid to the top of the dynamic piston and additionally to a parallel path leading to the bottom of the dynamic piston where a control valve is mounted.

Abstract: A tubing plug is adapted for insertion into a tubing string for sealing the tubing string. The tubing plug is comprised of a housing having an outer surface, wherein the housing is adapted for insertion in the tubing string such that an annulus is defined between the tubing string and the outer surface of the housing and wherein the housing defines a fluid passage therethrough, the fluid passage having an upper end and a lower end. A sealing mechanism is associated with the housing for sealing the annulus and a two-way fluid bypass is provided for selectively permitting a flow of a fluid across the sealing mechanism. Finally, a one-way valve is located at the lower end of the fluid passage for selectively permitting a flow of a fluid in a first direction from the upper end to the lower end of the fluid passage and for preventing a flow of a fluid in a second direction from the lower end to the upper end of the fluid passage.

Abstract: A device and method for selectively controlling the flow of production fluid through a tubing string in an oil and gas well according to which a housing is connected to a tubing string for insertion into the well, and well fluid is passed from the ground surface into the housing. The housing is provided with a plug to establish well fluid pressure in the housing to actuate a packer and/or other ancillary devices. The plug can be removed from the hosing by increasing the pressure of the well fluid in the housing above a predetermined value, thus permitting the flow of production fluid from the formation zone, through the housing and the tubing string, and to the ground surface.