Abstract: A tubing plug is preinstalled in a premium connection that allows support for the plug outside the drift dimension of the tubulars above and below. The plug is supported in a rotationally locked manner to avoid turning when being milled out. The plug shape internally comprises gentle sloping walls rather than surfaces in alignment with the longitudinal axis of the tubular to allow smaller cuttings to be produced that can be caught on a magnetic sub or circulated to the surface. Because the plug is supported in a zone outside the drift dimension of the adjacent tubulars, milling out the plug does not reduce the drift of the tubular assembly in which the plug was initially mounted. Seals can be provided for bubble tight sealing around the plug.

Abstract: An oil well completion tool having a tubular assembly defining an elongated main passage is adapted to be connected to a multiple-section tubing string within an oil well casing. A severable plug is mounted in the tubular assembly in normal blocking relationship to the passage. A movable shear cylinder unit has a plug-severing edge operable to sever an entire central segment of the plug from a remaining peripheral portion thereof. Separate hinge structure has an elongated U-shaped leg portion connected to the central segment of the plug. The leg portion of the hinge structure, which undergoes elongation, is operable to retain the severed central segment of the plug in the main passage while allowing the central segment of the plug to bodily shift independent of and in a direction away from the peripheral portion of the plug.

Abstract: A flow conduit having at least one orifice is placed in the vicinity of a flow source, which in one non-limiting embodiment may be a hydrocarbon reservoir. The flow pathway between the orifice and the source is temporarily blocked with a degradable barrier. Once the flow pathway is physically placed, the degradable barrier is removed under the influence of an acid, a solvent, time and/or temperature. The flow source and the flow pathways are at least partially covered (and flow blocked by) a temporary coating such as a pseudo-filter cake formed by a viscoelastic surfactant-gelled aqueous drill-in fluid, and the flow conduit is extended to the flow source. The pseudo-filter cake is removed when viscosity is reduced by an internal breaker, and flow is then allowed. The method is useful in one context of recovering hydrocarbons where the flow conduit is a telescoping sleeve or tube that contacts the borehole wall.

Abstract: An apparatus for controlling flow of a fluid into a wellbore tubular may include a flow control device controlling the flow of the fluid; and a disintegrating element associated with the flow control device. The flow control device may be actuated when the disintegrating element disintegrates when exposed to the flowing fluid. The disintegrating element may disintegrate upon exposure to water in the fluid. A method for producing fluid from a subterranean formation includes: configuring an element to disintegrate when exposed to a selected fluid; positioning the element in a wellbore; and actuating a flow control device using the element. The element may disintegrate when exposed to water. Actuating the flow control device may restrict a flow of fluid into a wellbore tubular.

Abstract: Disclosed herein is a temporary well isolation device, which is sealingly disposable in downhole tubing, and which has a housing with an axial passage. The temporary well isolation device also has frangible barrier element within the housing, where the frangible barrier element is sealingly engaged in the passage blocking fluid flow through the passage. The frangible barrier element bears a load from fluid pressure. The temporary well isolation device also has a disengagable constraint in contact with a frangible barrier element so as to redirect the load on the frangible barrier element from a first component of the load to a second component of the load, thereby preventing rupture of the frangible barrier element. Also disclosed herein is a method for disintegrating a frangible barrier element disposed in a passage of a temporary well isolation device.

Abstract: A method and apparatus for sealing a wellbore is described herein. A convertible seal includes a sealing element and a valve. The sealing element is in fluid communication with the valve and fluidly blocks a bore of the convertible seal. The sealing element prevents fluid from flowing through the bore until desired. When desired, the sealing element is removed to allow fluid to flow through the bore. Fluid flow in the bore is controlled by the valve. As a result, the convertible seal has been converted to a flow control seal.

Abstract: A method having the following steps: running a circulation valve comprising a reactive material into the well bore on the casing; reverse-circulating an activator material in the well bore until the activator material contacts the reactive material of the circulation valve; reconfiguring the circulation valve by contact of the activator material with the reactive material; and reverse-circulating a cement composition in the well bore until the reconfigured circulation valve decreases flow of the cement composition. A circulation valve for cementing casing in a well bore, the valve having: a valve housing connected to the casing and comprising a reactive material; a plurality of holes in the housing, wherein the plurality of holes allow fluid communication between an inner diameter of the housing and an exterior of the housing, wherein the reactive material is expandable to close the plurality of holes.

Abstract: A burst plug for positioning in a downhole fluid passage, the burst plug comprising: a shear disc installable in a sealing position in the fluid passage and openable by applying fluid at a burst pressure against the shear disc, a first part formed to retain the shear disc in a fluid flow blocking position after the shear disc is removed from its sealing position and the first part being selected to assume a shear disc retaining position when fluid at burst pressure is in communication therewith and thereafter to assume a second shear disc removal position when fluid in communication therewith is reduced to a selected pressure lower than the burst pressure.

Abstract: A frangible flapper valve that may be closed to hydraulically isolate a portion of a wellbore tubular. The flapper valve is made of a frangible material adapted to shatter upon impact from an impact sleeve. The sleeve may be used to initially hold open the flapper valve. A latching mechanism may be used to retain the sleeve above its initial position allowing the flapper to close isolating a portion of the tubular. The latching mechanism may engage a piston to retain the sleeve at the second position. A shearable device adapted to shear under a predetermined pressure selectively connects the piston to the tubular. When the pressure within the tubular increases above the predetermined amount the shearable device releases the piston and pushes the sleeve into the closed flapper valve causing the flapper valve to shatter. A second latching mechanism may prevent further movement of the sleeve.

Abstract: The present invention provides a cementing system and method for wellbores by cementing an annulus between a wellbore casing and a wellbore. In at least one embodiment, the invention includes a landing collar defining a restricted passage, a wellbore casing defining a passage coupled to the landing collar, a top cementing plug for sealingly engaging the wellbore casing, a bottom cementing plug for sealingly engaging the wellbore casing, and a fluid injection assembly coupled to the wellbore casing for injecting fluidic materials into the wellbore casing and controllably releasing the top cementing plug and the bottom cementing plug into the wellbore casing. The bottom cementing plug includes a plug body defining a plug passage, a frangible membrane for sealing the plug passage, and a one-way valve for controlling the flow of fluidic materials through the plug passage. The invention also includes the bottom cementing plug and methods for operation.

Abstract: Retractable ball seats having a housing, a seat, and a plug such as a ball are disclosed. The seat has a retracted position that prohibits the ball from passing through the passageway and an expanded position that permits the ball to pass through the passageway. A time delay material, such as a dissolvable material, maintains the seat in the retracted position. The time delay material disintegrates, degrades, or dissolves within a known period of time such that the retractable ball seat can be placed in a desired location in the wellbore and the ball will be released through the passageway within a known period of time.

Abstract: Devices and methods for methods for cleaning of excess cement from a production assembly as well as from the annulus surrounding the production assembly. A hydrostatic closed circulation valve (HCCV) assembly is described that is primarily actuatable between open and closed positions by varying hydraulic pressure in the flowbore of the production assembly. The valve assembly is useful for selectively circulating working fluid into the annulus from the flowbore of the production assembly.

Abstract: A flow conduit may have at least one orifice is in the vicinity of a flow source. The source is at least partially covered (and flow blocked by) an optional temporary coating or barrier. The flow pathway between the orifice and the source is temporarily blocked with a degradable material or barrier. The material disintegrates (e.g. under the influence of time or temperature) to optionally produce a product that removes the temporary coating in the area adjacent the barrier. The method is useful in one non-limiting context of recovering hydrocarbons where the flow conduit is the casing or liner of the well and the flow source is a subterranean reservoir where the temporary coating is a filter cake.

Abstract: An oil well completion tool having a tubular assembly defining an elongated main passage is adapted to be connected to a multiple-section tubing string within an oil well casing. A severable plug is mounted in the tubular assembly in normal blocking relationship to the passage. A movable shear cylinder unit has a plug-severing edge operable to sever an entire central segment of the plug from a remaining peripheral portion thereof. Separate hinge structure has an elongated U-shaped leg portion connected to the central segment of the plug. The leg portion of the hinge structure, which undergoes elongation, is operable to retain the severed central segment of the plug in the main passage while allowing the central segment of the plug to bodily shift independent of and in a direction away from the peripheral portion of the plug.

Abstract: A method of cementing an off bottom liner including the steps of establishing a first flow blockage in the liner at a location down-hole of a cementing valve located in the side wall of the liner, opening the cementing valve which exposes openings in the sidewall of the liner, pumping cement down the liner and out through the openings in the sidewall of the liner, establishing a second flow blockage up-hole of the cementing valve, closing the cementing valve, opening the second flow blockage to establish fluid communication through the second flow blockage, and opening the first flow blockage to establish fluid communication through the first flow blockage. The steps of opening the first and second flow blockages are achieved by increasing the pressure in the liner above the blockages. In this way, it is possible to cement an off bottom liner and regain fluid communication to the wellbore below the liner without the need for any drilling operations.

Abstract: A tubing string assembly for fluid treatment of a wellbore includes substantially pressure holding closures spaced along the tubing string, which each close at least one port through the tubing string wall. The closures are openable by a sleeve drivable through the tubing string inner bore.

Abstract: A downhole device used to divert fluid flow out of a work string. The downhole device may be located at any point along a work string at which it may be necessary to divert the fluid flow to the annulus. The downhole device may be activated and deactivated by inserting a single deformable dart into the work string. The device catches the dart blocking fluid flow through the work string. Increased fluid pressure activates the device, which diverts the fluid flow out of the work string into the annulus. A locating sleeve with a continuous j-track allows the device to be retained in activated position. The dart is adapted to deform under a predetermined amount of fluid pressure allowing the dart past the device and returning fluid flow through the work string. The downhole device may be activated multiple times without removing the downhole device from the wellbore.

Abstract: A method and apparatus for treating a subterranean section surrounding a wellbore with a fluid. In one embodiment, the apparatus comprises a three-dimensional tubular element capable of fluid flow in a wellbore with at least one burst disk with a pre-determined pressure rating positioned at a desired location on the tubular wherein the burst disk ruptures at the pre-determined pressure at the desired location on the tubular in the wellbore. The method provides the ability to choose the order in which the subterranean interval sections surrounding a wellbore are treated with fluid.

Abstract: Downhole devices including degradable materials and methods of using such devices to control downhole operations are disclosed. A method for controlling a downhole operation includes providing a device that includes a degradable material downhole; and degrading the degradable material to activate the device. Activation of the device may result in a displacement or flow (actuators) that may be used to control or monitor (sensor) a downhole oilfield operation. A downhole device for use in a well penetrating a formation includes, in part or in whole, a degradable material.

Abstract: A disposable downhole tool or a component thereof comprises an effective amount of biodegradable material such that the tool or the component thereof desirably decomposes when exposed to a wellbore environment. In an embodiment, the biodegradable material comprises a degradable polymer. The biodegradable material may further comprise a hydrated organic or inorganic solid compound. The biodegradable material may also be selected to achieve a desired decomposition rate when the tool is exposed to the wellbore environment. In an embodiment, the disposable downhole tool further comprises an enclosure for storing a chemical solution that catalyzes decomposition. The tool may also comprise an activation mechanism for releasing the chemical solution from the enclosure. In various embodiments, the disposable downhole tool is a frac plug, a bridge plug, or a packer.

Abstract: The present invention generally provides a pressure isolation plug for managing a wellbore with multiple zones. The pressure isolation plug generally includes a body with a bore extending therethrough, a first disintegratable ball sized and positioned to restrict upward fluid flow through the bore, wherein the disintegratable ball disintegrates when exposed to wellbore conditions for a first amount of time. The plug also includes a second ball sized and positioned to restrict downward fluid flow through the bore.

Abstract: A fluid system component is provided that is implemented as a section of metal pipe having a predetermined wall thickness and including a sacrificial element intended to preferentially fail upon the occurrence of certain predefined conditions. The sacrificial element takes the form of a window of predetermined geometry that covers an opening defined in the wall of the pipe. The window is configured to have a thickness substantially less than the wall thickness of the pipe, but nonetheless sufficiently great that the window remains materially unaffected by normal system operating conditions to which it is exposed. When the window is exposed to a pressure differential of predetermined magnitude, typically much greater than normal system operating pressures, the relatively thin window ruptures and permits the pressurized material, either inside or outside the pipe, to flow through the rupture.

Abstract: A method and apparatus for use in a subterranean well is described. The apparatus typically includes a mandrel and a packing element. The mandrel may have an outer surface and a non-circular cross-section and a the packing element may be arranged about the mandrel, the packing element having a non-circular inner surface matching the mandrel outer surface such that concentric rotation between the mandrel and the packing element is precluded. The apparatus may include slips having cavities to facilitate removal of the apparatus. The apparatus also may include a valve for controlling fluid flow through a hollow mandrel. The valve may include a flapper having at least one tab to engage at least one recession in the mandrel such that rotation between the mandrel and the valve is precluded when the valve is in a closed position. The apparatus may further include a central member which is releaseably attached to the mandrel by a release mechanism.

Abstract: A subsurface safety valve assembly for controlling fluid flow in a wellbore. In one embodiment, the subsurface safety valve assembly includes a tubular member having a longitudinal bore extending therethrough, a flapper removably connected to the tubular member. The flapper is configured to pivot against the tubular member between an open position and a closed position. The subsurface safety valve assembly further includes a flow tube disposed inside the tubular member and a shear sleeve having an upper end and a lower end. The upper end of the shear sleeve is positioned against a lower end of the flow tube to form a first seal between the upper end of the shear sleeve and the lower end of the flow tube.

Abstract: The present invention provides a bi-directional ball seat and method of use. In at least one embodiment, the present invention provides a fluid control system that includes a radial protrusion that can be selectively engaged and disengaged upstream and/or from a ball seat. For example, a ball can be placed in a passageway, engaged with a downstream ball seat, and the radial protrusion radially extended into the passageway distally from the seat relative to the ball. A reverse movement of the ball is restricted by the active radial movement of the radial protrusion into the passageway. The control system can be used to control a variety of tools associated with the well. Without limitation, the tools can include crossover tools, sleeves, packers, safety valves, separators, gravel packers, perforating guns, decoupling tools, valves, and other tools know to those with ordinary skills in the art.

Abstract: A tubing string assembly for fluid treatment of a wellbore includes substantially pressure holding closures spaced along the tubing string, which each close at least one port through the tubing string wall. The closures are openable by a sleeve drivable through the tubing string inner bore.

Abstract: The present invention is directed to disposable composite downhole tool formed of a resin-coated fiber. The fiber is formed of a degradable polymer, such as a poly(lactide) or polyanhydride. The resin is formed of the same degradable polymer as the fiber. It chemically bonds to the fiber, thereby making a strong rigid structure once cured. The fiber may be formed into a fabric before being coated with the resin. Alternatively, the fiber is formed of a non-biodegradable material.

Abstract: A casing hanger support assembly supports an inner casing string within a well containing an outer casing string and a production tubing string. The casing hanger support housing supports the casing hanger in the well, with a casing hanger being secured to an upper end of the inner casing string. One or more of a rupture disk and a blowout plug are provided in a wall of the casing hanger support housing for maintaining the desired pressure differential between an annulus within the outer casing string and an annulus exterior of the outer casing string, thereby preventing casing collapse or burst.

Abstract: Devices and methods for methods for cleaning of excess cement from a production assembly as well as from the annulus surrounding the production assembly. A hydrostatic closed circulation valve (HCCV) assembly is described that is primarily actuatable between open and closed positions by varying hydraulic pressure in the flowbore of the production assembly. The valve assembly is useful for selectively circulating working fluid into the annulus from the flowbore of the production assembly.

Abstract: A downhole tool (10) for selectively circulating fluid in a borehole is disclosed. The tool operates via the use of a combination of deformable drop balls (36) and smaller hard drop balls (40). In use a deformable drop ball (36) moves a sleeve (20) exposing a radial port (30,32) to provide fluid circulation radially from the tool. The smaller drop ball (40) can then obstruct the radial port (32,30) and by the increased pressure the deformable drop ball (36) is extruded through the tool. The resulting pressure differential as the drop ball (36) moves causes the sleeve (20) to rise, releasing the smaller drop (40) ball and closing the radial port (32,30). The process can be repeated to selectively circulate fluid through the tool.

Abstract: The present invention provides a cementing system and method for wellbores by cementing an annulus between a wellbore casing and a wellbore. In at least one embodiment, the invention includes a landing collar defining a restricted passage, a wellbore casing defining a passage coupled to the landing collar, a top cementing plug for sealingly engaging the wellbore casing, a bottom cementing plug for sealingly engaging the wellbore casing, and a fluid injection assembly coupled to the wellbore casing for injecting fluidic materials into the wellbore casing and controllably releasing the top cementing plug and the bottom cementing plug into the wellbore casing. The bottom cementing plug includes a plug body defining a plug passage, a frangible membrane for sealing the plug passage, and a one-way valve for controlling the flow of fluidic materials through the plug passage. The invention also includes the bottom cementing plug and methods for operation.

Abstract: A fluid system component is provided that is implemented as a section of metal pipe having a predetermined wall thickness and including a sacrificial element intended to preferentially fail upon the occurrence of certain predefined conditions. The sacrificial element takes the form of a window of predetermined geometry that covers an opening defined in the wall of the pipe. The window is configured to have a thickness substantially less than the wall thickness of the pipe, but nonetheless sufficiently great that the window remains materially unaffected by normal system operating conditions to which it is exposed. When the window is exposed to a pressure differential of predetermined magnitude, typically much greater than normal system operating pressures, the relatively thin window ruptures and permits the pressurized material, either inside or outside the pipe, to flow through the rupture.

Abstract: The method of operating a subsurface safety valve and preventing or remediating the formations of hydrate, wax, or paraffin solids in the well bore of an oil or gas well comprising coating the external area of the intermediate portion of a string of tubing to electrically insulate said intermediate portion of said string of tubing, inserting said surface control valve into a well bore pipe on a string of tubing, electrically grounding said surface control valve to said well bore pipe, communicating an electrical signal from the surface along said string of tubing, to said surface control valve, and along said well bore pipe back to said surface, closing said surface control valve upon the interruption of said electrical signal, and using the electrical resistance of said string of tubing to heat the wall of said string of tubing.

Abstract: The present invention provides a bi-directional ball seat and method of use. In at least one embodiment, the present invention provides a fluid control system that includes a radial protrusion that can be selectively engaged and disengaged upstream and/or from a ball seat. For example, a ball can be placed in a passageway, engaged with a downstream ball seat, and the radial protrusion radially extended into the passageway distally from the seat relative to the ball. A reverse movement of the ball is restricted by the active radial movement of the radial protrusion into the passageway. The control system can be used to control a variety of tools associated with the well. Without limitation, the tools can include crossover tools, sleeves, packers, safety valves, separators, gravel packers, perforating guns, decoupling tools, valves, and other tools know to those with ordinary skills in the art.

Abstract: A rotary valve assembly for a rotary steerable tool is disclosed for directing flow of an abrasive laden drilling fluid; the valve assembly has a first sealing surface rotatably engaging a second sealing surface. At least one of the surfaces has at least about 5% of its area comprising interconnecting voids to an average depth of at least 0.02 mm. The interconnected voids allow fluid pressure to equalize between the sealing faces by flowing through the interconnecting voids to the sealing surfaces. Because the fit of the sealing surfaces of the valve is less than perfect, and because the voids on mating surfaces do not necessarily overlap, the 5% of the surface area comprising interconnected voids can easily translate to a 10% or more reduction in sealed area when both sealing surfaces have the interconnecting voids. The additional reduction in surface area subjected to differential pressure has substantially eliminated the hydraulic lock problem previously encountered upon startup.

Abstract: Equipment and methods which may be used in conjunction with an underbalanced well completion. In a described embodiment, a valve for use in a subterranean well in conjunction with a tool conveyed through the valve in a container is provided. The valve includes a passage formed longitudinally through the valve, a closure assembly which selectively permits and prevents flow through the passage, and an engagement device which engages the container as the tool is conveyed through the passage. The closure assembly permits flow through the passage when the container is conveyed into the passage, and the closure assembly prevents flow through the passage when the container is removed from the passage. Engagement between the container and the engagement device separates the tool from the container.

Abstract: The multiple interventionless actuated downhole valve includes a valve movable between an open and a closed position to control communication between an annular region surrounding the valve and an internal bore and more specifically controlling communication between above and below the valve, and at least two remotely operated interventionless actuators in operational connection with the valve, wherein each of the interventionless actuators may be operated independently by absolute tubing pressure, absolute annulus pressure, differential pressure from the tubing to the annulus, differential pressure between the annulus and the tubing, tubing or annulus multiple pressure cycles, pressure pulses, acoustic telemetry, electromagnetic telemetry or other types of wireless telemetry to change the position of the valve and allowing the valve to be continually operated by mechanical apparatus.

Abstract: A method and apparatus for selectively actuating a dual check valve assembly within a well for a direct circulating operational mode or a reverse circulating operational mode. A tubular housing which may be connected to well tubing is provided with a check valve assembly and may be provided with a rotatable J-slot mode indexing sleeve having an internal J-slot geometry. An inner tubular member which also may be connected to well tubing is linearly movable within the tubular housing to a valve open position, an indexing position and a valve enabled position being controlled by the J-slot geometry of the J-slot indexing sleeve or being controlled by moving the inner tubular element and resisting movement of the tubular housing. Relative positioning of the inner tubular member and the tubular housing to selective valve mode positions may also be achieved responsive to fluid flow, by mechanical compression, or by motion operation.

Abstract: A sealed multilateral junction system provides fluid isolation between intersecting wellbores in a subterranean well. In a described embodiment, a method of forming a wellbore junction includes the steps of sealing a tubular string in a branch wellbore to a tubular structure in a parent wellbore. The tubular string may be secured to the tubular structure utilizing a flange which is larger in size than a window formed in the tubular structure. The flange may be sealed to the tubular structure about the window by a metal to metal seal or by adhering the flange to the tubular structure.

Abstract: The present invention provides for a tool having diverter valves to reduce the pressure in a wellbore caused by frictional resistance to fluid flow as the beta wave of a gravel pack operation makes its way up the wellbore.

Abstract: An operator controlled, selectively actuatable downhole dump valve assembly (22) for selective draining of pumping liquid from a producing oil well, sectionalized downhole pipe string (18). The assembly (22) includes a tubular pipe section (24) having endmost threading (34, 38) and a dump valve rupture disc fitting unit (26); the fitting unit (26) includes a metallic, concavo-convex disc (50) with preformed lines of weakness (52, 54) on one face thereof. The section (24) is interconnected between a pair of lower pipe sections (20a, 20b). In operation when it is desired to elevate the string (18) from the well, the fluid within the string (18) is pressurized sufficiently to rupture the disc (50), thereby allowing fluid within the string (18) to drain. The string (18) and other well components can thereby be removed from the well without contamination owing to spillage from the tubular string (18).

Abstract: An embodiment of a downhole tool for use with a workstring in a wellbore includes a first section, a second section, and a coupling mechanism adapted such that in a first configuration the coupling mechanism couples the first section to the second section. In a second configuration, the coupling mechanism does not couple the first section to the second section. Also disclosed is a method for creating a plug in a wellbore, the method comprising: injecting a slurry into the workstring to form a plug in the wellbore, positioning a flow preventing mechanism into the workstring to prevent fluid flow from exiting the workstring, inducing a coupling mechanism to uncouple a portion of the workstring such that the portion remains with the slurry to create the plug in the wellbore, and removing the first section from the wellbore.

Abstract: A fluid system component is provided that is implemented as a section of metal pipe having a predetermined wall thickness and including a sacrificial element intended to preferentially fail upon the occurrence of certain predefined conditions. The sacrificial element takes the form of a window of predetermined geometry that covers an opening defined in the wall of the pipe. The window is configured to have a thickness substantially less than the wall thickness of the pipe, but nonetheless sufficiently great that the window remains materially unaffected by normal system operating conditions to which it is exposed. When the window is exposed to a pressure differential of predetermined magnitude, typically much greater than normal system operating pressures, the relatively thin window ruptures and permits the pressurized material, either inside or outside the pipe, to flow through the rupture.

Abstract: An improved dump valve assembly (22) is provided for use as a part of an elongated, sectionalized, tubular downhole pipe string (18). The assembly (22) includes a tubular pipe section (24) having endmost threading (34, 38) and a rupture disc fitting (26); the fitting (26) includes a metallic, preferably concavo-convex disc (50) with preformed lines of weakness (52, 54) on one face thereof. The section (24) is interconnected between a pair of lower pipe sections (20a, 20b). In operation when it is desired to elevate the string (18) from the well, the fluid within the string (18) is pressurized sufficiently to rupture the disc (50), thereby allowing fluid within the string (18) to drain. The string (18) and other well components can then be removed from the well without contamination owing to spillage from the tubular string (18).

Abstract: A downhole tool (10) for selectively circulating fluid in a borehole is disclosed. The tool operates via the use of a combination of deformable drop balls (36) and smaller hard drop balls (40). In use a deformable drop ball (36) moves a sleeve (20) exposing a radial port (30,32) to provide fluid circulation radially from the tool. The smaller drop ball (40) can then obstruct the radial port (32,30) and by the increased pressure the deformable drop ball (36) is extruded through the tool. The resulting pressure differential as the drop ball (36) moves causes the sleeve (20) to rise, releasing the smaller drop (40) ball and closing the radial port (32,30). The process can be repeated to selectively circulate fluid through the tool.

Abstract: Apparatus for a one trip completion of fluid production wells. A completion tool string includes a pressure activated cementing valve, an external casing packer, a pressure activated production valve, an opening plug and a plug landing collar and a closing plug and seat. This tool series is assembled near the end of a production tube string upstream of the well production screen.

Abstract: A ball release mechanism is mounted near the intended seat. The ball or balls are kept out of the circulating stream. High circulation rates followed by curtailment of circulation places an outlet port in position to allow the ball or balls to be pushed out by a spring. The spring or one of the balls prevents the return of an ejected ball back into the protected pocket. The ball is delivered to the seat without circulation.

Abstract: A modified casing coupling and burst disk assembly are used to prevent critical annular pressure buildup in an offshore well. The modified casing coupling includes a receptacle, or receptacles, for a modular burst disk assembly. The burst disk assembly is retained by threads or a snap ring and is sealed by the retaining threads, or an integral o-ring seal. The disk fails at pressure specified by the user but before trapped annular pressure threatens the integrity of the outer casing. The design allows for the burst disk assembly to be installed on location or before pipe shipment.

Abstract: A unitary, forward buckling rupture disc is provided that is adapted to be mounted in a holder in which the disc is in closing relationship to a tubing string in an oil well and has greatest utility for testing the integrity of the connection between the sections of oil well tubing strings. The disc is designed to withstand the fluid pressure head in the string and a leak test pressure, and to then burst and fully open under a predetermined overpressure. The concavo-convex bulged section of the disc has a non-circular, continuous score line formed in the concave face thereof. The score line is of continuously varying depth around its circumference and includes an outwardly projecting cam segment which is of greatest depth that ruptures first and is in direct opposition to a lesser depth score line portion forming a hinge area for the burst region of the disc.

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.