Abstract: A method of actuating multiple valves in a well can include applying a pressure cycle to the valves without causing actuation of any of the valves, and then simultaneously reducing pressure applied to the valves, thereby actuating the valves. Another method can include releasing a locking device of each valve which prevents actuation, and then reducing pressure applied to the valves, thereby actuating the valves. A valve can include a port which provides for fluid communication between an exterior and an interior of the valve, a closure member which selectively permits and prevents fluid flow through the port, the closure member permits flow through the port in response to a decrease in a pressure differential from the interior to the exterior of the valve, and a locking device which prevents displacement of the closure member, the locking device being released in response to mechanical force applied to the locking device.

Abstract: A mud saver valve, positionable at the bottom of the drill string, above the bit, which includes an elongated body portion; portion of the valve housing a compressible spring a pressure; a valve mechanism which is a sliding sleeve moveable between open and closed positions within the valve; while in the closed position, drilling fluid cannot pass through the valve; when a combination of static and pump pressure exceeds the setting pressure of the dome, the sleeve will be moved by actuation pistons to the open position, at which drilling fluid is allowed to through the valve. Also, wherein when the valve is normally closed, as long as the fluid column pressure is less than the setting pressure, the valve remains closed, and allows the drill string to be disconnected and a section of pipe can added without the fluid draining from the drill column above the bit, and thus saving fluid.

Abstract: A downhole tool comprising an inner sleeve with a plurality of sleeve ports and a housing positioned radially outwardly of the inner sleeve and having a plurality of housing ports, with the housing and inner sleeve partially defining a space radially therebetween. The space is occupied by a shifting sleeve. A fluid path extends between the interior flowpath of the tool and the space. A fluid control device, such as a burst disk, occupies at least portion of the fluid path. In one state, the shifting sleeve is in a first position between the housing ports and the sleeve ports to prevent fluid flow between the interior flowpath and exterior of the tool. The fluid control device may selectively permit fluid flow, and thus pressure communication, into the annular space to cause a differential pressure across the shifting sleeve.

Abstract: A downhole drilling valve tool, positioned above the drill bit, which utilizes a ball valve having a through bore for normal flow. The ball valve is operated bidirectionally by a piston driven mechanism between an open position and a closed position. The piston mechanism is responsive to a reference accumulator pressure on a first side and the pressure in the apparatus bore above the ball valve on a second side. Whenever the valve apparatus is lowered at least a minimum distance into the well bore, a pressure relief valve is used to maintain a fixed margin between the flowing bore pressure and the accumulator pressure. Closure of the ball valve occurs when the accumulator pressure exceeds the bore pressure during pump stoppages. The downhole drilling valve tool offers a more wear resistant sealing means, as well as higher pressure operability than conventional downhole check valves.

Abstract: A flow restrictor includes resilient flaps that can flex outward to an open position in response to fluid flow pressure and return to an initial position at which the resilient flaps restrict fluid flow more than in the open position. The resilient flaps can overlap and variably restrict fluid flow based on fluid flow pressure. The flow restrictor can be used on a transport tube to avoid a need for a packing tube in an alternative path system to deliver gravel packing slurry.

Abstract: A system, in certain embodiments, includes a subsurface safety valve (SSV) biased toward a closed position, and configured to open by application of hydraulic pressure. The system also includes a tubing hanger running tool (THRT), including a conduit in fluid communication with the SSV, and a pressure release valve fluidly coupled to the conduit. The pressure release valve is configured to maintain sufficient hydraulic pressure within the conduit to hold the SSV in an open position while the pressure release valve is in a closed position.

Abstract: A subsurface safety valve particularly designed for high temperature and high pressure applications has an improved tubular joint connection that provides for a compliant metal to metal seal without adversely affecting the break out torque. The valve also includes axially extending grooves in the inner surface of the tubular housing in the area of a actuating piston bore to relief stresses in that area thereby reducing the risk of stress failure.

Abstract: A valve with a shuttle for use in a flow management system is capable of bypassing a backflow.

Abstract: A downhole tester valve (100) includes a housing assembly (106) and a mandrel assembly (172, 174) that define therebetween an operating fluid chamber (176), a biasing fluid chamber (184) and a power fluid chamber (180). A valve assembly (126) disposed within the housing assembly (106) is operable between open and closed positions. A piston assembly (146) is operably associated with the valve assembly (126) such that annulus pressure entering the power fluid chamber (180) pressurizes operating fluid in the operating fluid chamber (176) which acts on the piston assembly (146) to shift the valve assembly (126) from the closed position to the open position and such that predetermined travel of the piston assembly (146) opens a bypass passageway (162) for the pressurized operating fluid to charge biasing fluid in the biasing fluid chamber (184), thereby enabling closure of the valve assembly (126) upon reducing annulus pressure by a predetermined amount.

Abstract: Systems and methods for activating a down hole tool in a wellbore. A piston is moveable from a first position to a second position for activating the down hole tool. The piston includes a first side exposed to an activation chamber, and a second side operatively coupled to the down hole tool. A rupture member has a first side exposed to the activation chamber and a second side exposed to the interior of a base pipe. The rupture member is configured to rupture when a pressure differential between the activation chamber and the interior reaches a predetermined threshold value, at which point the rupture member allows fluid communication between the interior and the activation chamber to pressurize the activation chamber and move the piston, thereby activating the down hole tool.

Abstract: Apparatus and methods for controlling the flow of fluid, such as formation fluid, through an oilfield tubular positioned in a wellbore extending through a subterranean formation. Fluid flow is autonomously controlled in response to change in a fluid flow characteristic, such as density or viscosity. In one embodiment, a fluid diverter is movable between an open and closed position in response to fluid density change and operable to restrict fluid flow through a valve assembly inlet. The diverter can be pivotable, rotatable or otherwise movable in response to the fluid density change. In one embodiment, the diverter is operable to control a fluid flow ratio through two valve inlets. The fluid flow ratio is used to operate a valve member to restrict fluid flow through the valve.

Abstract: A dual barrier side pocket mandrel with gauge includes a gas lift barrier valve mandrel with permanent sensors and at least two pockets for accepting gas lift barrier valves, wherein the pockets are connected via a port. The mandrel also includes a production conduit along a central longitudinal axis. The mandrel is encompassed by a casing on the inside of a well. The permanent sensors can monitor a pressure or a temperature in the casing, production conduit, and port to determine the status of the individual gas lift barrier valves.

Abstract: An inflow control device may include flow control elements along a flow path. The flow control elements may change the inertial direction of the fluid flowing in the flow path. The change in inertial direction occurs at junctures along the flow path. The flow control elements may also be configured to form segmented pressure drops across the flow path. The segmented pressure drops may include a first pressure drop segment and a second pressure drop segment that is different from the first pressure drop segment. The pressure drop segments may be generated by a passage, an orifice or a slot. In embodiments, the plurality of flow control elements may separate the fluid into at least two flow paths. The flow control elements may also be configured to cause an increase in a pressure drop in the flow path as a concentration of water increases in the fluid.

Abstract: A subsurface safety valve is operable to close a fluid flow path by virtue of an axially movable flow sleeve. The valve includes a recockable actuator and a latch mechanism so that the valve can be moved to a closed position without overcoming the pressure head and frictional forces currently encountered in conventional safety valves. The latch mechanism includes one or more micro pistons.

Abstract: An apparatus for isolating a first zone from a second zone in a subterranean wellbore. The apparatus includes an outer tubular and an inner tubular disposed within the outer tubular forming an annular flow path therebetween that is in fluid communication with the first zone. The inner tubular defines a central flow path that is in fluid communication with the second zone. A sleeve having at least one seal is positioned in the annular flow path and is axially movable relative to the inner and outer tubulars between a closed position wherein the seal engages the inner tubular and an open position wherein the seal engages the outer tubular. A mandrel is slidably disposed within the inner tubular and is coupled to the sleeve. The mandrel is operable to shift the sleeve between the open position and the closed position responsive to changes in pressure within the central flow path.

Abstract: A method of opening a conduit cemented in a subterranean well can include flowing a fluid through a passage in the well after the conduit is cemented in the well, and the conduit opening in response to the flow of the fluid through the passage. A well system can include a flow control device cemented in a wellbore, and a conduit positioned adjacent a passage of the flow control device, whereby the conduit opens in response to the passage being opened.

Abstract: The present invention relates to a blow-out prevented utilized to ensure that high pressure material stay contained and do not enter an oil platform riser, thereby preventing explosions, damage, oil spills, injury, loss of life and other issues that may be common to oil platform accidents. Specifically, the present invention relates to an automatic blow-out preventer that cuts off communication between a casing and a riser automatically when pressures rise within the casing. More specifically, the blow-out preventer comprises a plurality of curved blades or “petals” that automatically close to seal off casing pressure from riser pressure when pressure rises within the casing.

Abstract: A multi functional assembly adaptable within a tubing string conduit to serve as a safety valve against the possibility of a blow out. Both surface and subsurface controllable, it offers both a partially retrievable or totally retrievable system that allows unbiased and unlimited work over and wire line access to an entire tubing string and can provide safety for down hole well work. The preferred invention comprises a housing mandrel system including closure elements reciprocally mounted vertically within the safety valve conduit that when unengaged provides unrestricted flow and when engaged provides restriction amounting from limited flow to complete closure of a tubing string. The invention provides operational options to function hydraulically and mechanically while having the additional capability of being remotely controlled automatically, electronically, and manually.

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: Apparatus and methods for controlling the flow of fluid, such as formation fluid, through an oilfield tubular positioned in a wellbore extending through a subterranean formation. Fluid flow is autonomously controlled in response to change in a fluid flow characteristic, such as density or viscosity. A fluid diverter is movable between an open and closed position in response to fluid density change and operable to restrict fluid flow through a valve assembly inlet. The diverter can be pivotable, rotatable or otherwise movable in response to the fluid density change. The diverter is operable to control a fluid flow ratio through two valve inlets. The fluid flow ratio is used to operate a valve member to restrict fluid flow through the valve.

Abstract: An actuating method includes applying an input pressure to a first side of a tool operator and to a second side of the tool operator and moving the tool operator from a first position to a second position in response to depleting the input pressure applied to the second side. A state of a tool element can be changed in response to moving the tool operator from the first position to the second position. The input pressure may be depleted from the second side of the tool operator by transferring hydraulic fluid to a confined diameter container disposed in an annular region of the actuating device or to the first side of the tool operator.

Abstract: Apparatus and methods for controlling the flow of fluid, such as formation fluid, through an oilfield tubular positioned in a wellbore extending through a subterranean formation. Fluid flow is autonomously controlled in response to change in a fluid flow characteristic, such as density or viscosity. A fluid diverter is movable between an open and closed position in response to fluid density change and operable to restrict fluid flow through a valve assembly inlet. The diverter can be pivotable, rotatable or otherwise movable in response to the fluid density change. The diverter is operable to control a fluid flow ratio through two valve inlets. The fluid flow ratio is used to operate a valve member to restrict fluid flow through the valve.

Abstract: A tool that is usable with a well includes a valve element, a mechanical operator, a pressure chamber and a regulator. The valve element has a first state and a second state. The mechanical operator responds to a predetermined signature in an annulus pressure relative to a baseline level of the annulus pressure to transition the valve element from the first state to the second state. The pressure chamber exerts a chamber pressure to bias the mechanical operator to transition from the second state to the first state. The baseline level is capable of varying over time, and the regulator regulates the chamber pressure based on the baseline level.

Abstract: A downhole fluid flow control system (100). The flow control system (100) includes a flow control component (122) having direction dependent flow resistance created by a vortex chamber (144). Production fluids (140) that travel through the flow control component (122) in a first direction enter the vortex chamber (144) traveling primarily in a tangential direction (148) to experience a first pressure drop. Injection fluids (150) that travel through the flow control component (122) in a second direction enter the vortex chamber (144) traveling primarily in a radial direction (152) to experience a second pressure drop. The pressure drop created by the tangential flow (148) of the production fluids (140) is greater than the pressure drop created by the radial flow (152) of the injection fluids (150).

Abstract: A system for controlling flow in a wellbore uses a downhole flow control device positioned at a downhole location in the wellbore. The flow control device has a movable element for controlling a downhole fluid flow. In response to an applied pressure pulse, the movable element moves in finite increments from one position to another. In one embodiment, a hydraulic source generates a transmitted pressure pulse to the flow control device wherein the maximum pressure of a received pressure pulse downhole is sufficient to overcome a static friction force associated with the movable element, and wherein a minimum pressure of the received pressure pulse downhole is insufficient to overcome a dynamic friction force associated with the movable element.

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: Hydraulic pulses are produced each time that a pulse valve interrupts the flow of a pressurized fluid through a conduit. The pulse valve includes an elongate housing having an inlet configured to couple to the conduit to receive the pressurized fluid, and an outlet configured to couple to one or more tools. In the housing, a valve assembly includes a poppet reciprocating between open and closed positions, and a poppet seat, in which the poppet closes to at least partially block the flow of pressurized fluid through the valve. A pilot within the poppet moves between disparate positions to modify fluid paths within the valve. When the valve is open, a relatively lower pressure is produced by a Venturi effect as the fluid flows through a throat in the poppet seat, to provide a differential pressure used to move the pilot and poppet. An optional bypass reduces the pulse amplitude.

Abstract: A downhole fluid flow control system includes a fluidic module (150) having a main fluid pathway (152), a valve (162) and a bridge network. The valve (162) has a first position wherein fluid flow through the main fluid pathway (152) is allowed and a second position wherein fluid flow through the main fluid pathway (152) is restricted. The bridge network has first and second branch fluid pathways (163, 164) each having a common fluid inlet (166, 168) and a common fluid outlet (170, 172) with the main fluid pathway (152) and each including two fluid flow resistors (174, 176, 180, 182) with a pressure output terminal (178, 184) positioned therebetween. In operation, the pressure difference between the pressure output terminals (178, 184) of the first and second branch fluid pathways (163, 164) shifts the valve (162) between the first and second positions.

Abstract: A self-actuated cyclical flow interruption valve on a deployment tool is positioned at a proximal end of a well completion assembly. Fluid is pumped though the self-actuated cyclical flow interruption valve and vented immediately distal of the valve, to return to surface of the well. A water hammer pulse is generated each time the self-actuated cyclical flow interruption valve closes, thereby generating an impact force that acts to push the completion equipment distally into the well. The continuous cyclic force of the impact facilitates placement of the completion equipment where desired in the well, including within a horizontal extension of the well. Fluid discharged through the self-actuated cyclical flow interruption valve circulates up to the surface through a vertical and inclined section of the well.

Abstract: An automatic vent valve and method for use is provided equalizing the pressure in at least two lines. A housing has a first piston that compresses a bias device when the second pressure source supplies sufficient pressure. Upon a sufficient reduction in pressure the first piston releases a second internally held coaxial piston to allow fluid to flow from a first pressure source towards a second pressure source, thereby equalizing the pressure between the two pressure sources.

Abstract: A valve assembly (2) which is configured to be coupled to a tubing string comprises a housing (8) defining a housing flow path (9) for communicating with the tubing string, and a barrier member (14) located in the housing (8) and configurable between a normally-closed position in which the barrier member (14) restricts access through the housing flow path (9), and an open position in which access is permitted through the housing flow path (9). The valve assembly (2) also comprises a bypass arrangement reconfigurable between an open state in which the bypass arrangement defines a bypass flow path that communicates with the housing flow path (9) on opposite sides of the barrier member (14) to permit fluid to bypass the barrier member and thereby fill the tubing string, and a closed state in which fluid is prevented from bypassing the barrier member to thereby permit pressurization of the tubing string.

Abstract: Wellbore flow control devices can be used in various subterranean operations to regulate access of formation fluids to the interior of a wellbore pipe and/or to limit the access of unwanted fluids thereto. Coupling of flow regulating assemblies to one another in the wellbore flow control devices can result in improved operational performance in regulating formation fluid flow to the interior of the wellbore pipe compared to using the flow regulating assemblies in an uncoupled state. Wellbore flow control devices can comprise a gate valve assembly that is in fluid flow communication with a flow restricting assembly, where each assembly is located on the exterior of a wellbore pipe and the flow restricting assembly is in fluid flow communication with the interior of the wellbore pipe.

Abstract: When injecting liquids into the ground, imposing pulses on the injected liquid is effective to increase penetration and saturation of the ground. Imposing suckback onto the pulses is effective to make the liquid in the ground behave as a coherent unitary body, surging out and back each pulse, and to super-saturate the ground. The tool includes a suckback-chamber, which is timed to open to the ground formation just as the pulse-valve closes. A biasser (e.g a spring) drives the chamber open and sucks in some of the liquid from the ground. The chamber is then emptied, back to the ground, by the rising pressure as the pulsing tool is recharged. The suckback-chamber can be added to any type of pulsing tool.

Abstract: A bypass assembly for use in a downhole tool comprises a chamber, a first fluid port in fluid communication with the chamber, a second fluid port in fluid communication with the chamber, a flow restrictor disposed in a first flow path between the first fluid port and the second fluid port, a piston moveable in a first direction by the application of a first fluid pressure, a biasing member, and a restraining member disposed adjacent to the piston. The biasing member biases the piston to move in a second direction opposite the first direction, and the restraining member is actuated by movement of the piston in the first direction in response to a predetermined fluid pressure. Movement of the piston in the second direction to a predetermined position configures the bypass assembly to divert fluid flow around the flow restrictor along a second flow path.

Abstract: A downhole tool in a drill string for mitigating hazards of a blockage in an annulus of the drill string. The downhole tool can sense blockages and selectively recirculate flow from within the annulus back to surface. Further, the downhole tool is made up of segments that are selectively detachable from one another, so that the segments above the point of detachment are removable from a wellbore. The bypass assembly includes a sleeve in the downhole tool with openings in its side; when the annulus reaches a set pressure, the sleeve slides to a position so the openings register with ports formed through a side of the tool to allow bypass flow. A processor in the downhole tool senses movement of the string, and when the string is axially stationary more than a designated period of time, the processor emits signals to detach the segments.

Abstract: A control mechanism for a downhole tool including a mandrel having a throughbore, at least one activation port, and at least one bypass port, a first sleeve detachably mounted within the throughbore at a first position and moveable to a second position, the first sleeve having a first seat, and a second sleeve detachably mounted within the throughbore at a third position located axially above the first position and moveable to a fourth position, the second sleeve having a second seat. A method of hydraulically actuating and deactuating a downhole tool, the method including disposing the downhole tool and a control mechanism in a well.

Abstract: A safety valve system for use in a subterranean well can include a safety valve protector connected downstream of a safety valve, whereby when closed the safety valve protector reduces a flow rate through the safety valve and prevents displacement of an object through the safety valve protector to the safety valve. Another safety valve system can include a safety valve protector which, when closed, reduces a flow rate through a safety valve, and the safety valve protector closes in response to the flow rate through the safety valve being above a predetermined level. In another safety valve system, each of the safety valve protector and the safety valve comprises an actuator, the actuators being connected by a line, and a signal transmitted by the line causes the safety valve protector actuator to close the safety valve protector, and then causes the safety valve actuator to close the safety valve.

Abstract: A barrier valve system includes one or more barrier valves, a connection sub having a first portion and a second portion connecting one or more control lines to each other, and a replacement portion of the connection sub connectable to the first portion subsequent to retrieval of the second portion. The replacement portion has a port from an outside diameter of the replacement portion to an inside diameter of the replacement portion and seals disposed to define an annular space between the replacement portion and the first portion encompassing only valve opening ports in the first portion.

Abstract: Methods and related systems are described for controlling inflow of fluid into a production string. In aspects, the invention provides an inflow control device with a shut-off feature that is operated automatically utilizing swellable materials.

Abstract: An apparatus is described for controlling fluid flow in a downhole tubular. Fluid is flowed through a flow control system having a flow ratio control system and a pathway dependent resistance system. The flow ratio control system has a first and second passageway, where the ratio of fluid flowing through the passageways dependent on a characteristic of the fluid flow. The pathway dependent resistance system includes a vortex chamber with a first inlet directing flow primarily tangentially into the vortex chamber and the second inlet directing flow primarily radially into the vortex chamber. Undesired fluids, such as gas or water, in an oil well, are directed, based on their relative fluid flow characteristics, into the vortex primarily tangentially, thereby restricting flow when the undesired fluid is present.

Abstract: For injecting e.g. water into ground formation around a borehole, and for superimposing pulses onto the outflow of the injected water, it is important that the pulses have a rapid rise-time. A piston is connected to a pulse-valve of the tool. A bias spring urges the piston towards its closed position. The piston is urged towards the open position by a differential PDAF between the supplied accumulator-pressure and the in-ground formation-pressure. When the pulse-valve is open, the PDAF is falling, until the force of the spring closes the pulse-valve. Then the PDAF rises, but now the PDAF acts over only a small area of the piston. When the PDAF is high enough to ease the pulse-valve open, suddenly the whole area of the piston is exposed to the PDAF, whereby the pulse-valve opens violently.

Abstract: This disclosure relates to an improved system and method for fracturing a well. In one embodiment, the system can comprise a base pipe comprising an insert port capable of housing a stop ball partially within the chamber of it, and a sliding sleeve. The sliding sleeve can comprise a first sleeve with an in inner surface. That inner surface can comprise a void. The first sleeve can be maneuverable into two positions. In the first position, the void can rest on a surface of the base pipe not comprising an insert port. Such positioning can prevent a stop ball from exiting the chamber of the base pipe. In the second position, the void can rest over an insert port. Such positioning can allow the stop ball to the chamber of said base pipe and to enter the void.

Abstract: A method of treating production fluid in a wellbore includes deploying a capillary string into the wellbore. The capillary string has a plurality of injection valves. The method further includes pumping treatment fluid through the capillary string and into the wellbore. The injection valves have a cumulative set pressure greater than or equal to a hydrostatic pressure of the treatment fluid.

Abstract: Apparatus (10) for restricting a flow of fluid through a bore (14) comprises a bore sealing member (12a) and an actuation assembly for moving the bore sealing member (12a) between first and second configurations. The actuation assembly is configured to isolate first and second end portions (46, 48) of the activation member (12a) from a bore fluid (50). The apparatus (10) provides for moving the bore sealing member (12a) between the first and second configurations without a bore fluid (50) pressure acting on an end portion (46, 48) of the activation member (12a).

Abstract: A valve assembly for use in aquifer liquid flow control in accordance with one embodiment can be used to deliver liquid to and/or from at least one selected aquifer in a plural aquifer system. In accordance with an embodiment, the valve can be used to route liquid to or from a first aquifer without delivering liquid to or from a second aquifer, or to or from the second aquifer without delivering liquid to or from the first aquifer. As an aspect of an embodiment, the valve assembly can be used to shut off the flow of liquid to both the first and second aquifers.

Abstract: A flow control device comprises a fluid pathway configured to provide fluid communication between an exterior of a wellbore tubular and an interior of the wellbore tubular, a flow restriction disposed in a fluid pathway, a flow blockage disposed in the fluid pathway, and a retaining member configured to maintain the flow blockage within the fluid pathway and allow access to the flow blockage within the fluid pathway. The flow blockage substantially prevents a fluid flow through the fluid pathway.

Abstract: A flow stop valve (20) positionable in a downhole tubular (6), and a method, are provided. The flow stop valve (20) is in a closed position when a pressure difference between fluid outside the downhole tubular (6) and inside the downhole tubular (6) at the flow stop valve (20) is below a threshold value, thereby preventing flow through the downhole tubular. The flow stop valve (20) is in an open position when the pressure difference between fluid outside the downhole tubular (6) and inside the downhole tubular (6) at the flow stop valve (20) is above a threshold value, thereby permitting flow through the downhole tubular (6).

Abstract: A downhole fluid flow control system includes a fluidic module having a turbine chamber. A flow control turbine is rotatably disposed within the turbine chamber. The flow control turbine is operable to provide fluid discriminating flow resistance such that a pressure drop for a desired production fluid passing through the fluidic module is less than a pressure drop for an undesired production fluid passing through the fluidic module. For example, the flow control turbine is operable generate a greater pressure drop in water produced therethrough as compared to oil produced therethrough due to differences in the density, viscosity or other property of the produced fluid.

Abstract: A vortex-controlled variable flow resistance device ideal for use in a backpressure tool for advancing drill string in extended reach downhole operations. The characteristics of the pressure waves generated by the device are controlled by the growth and decay of vortices in the vortex chamber(s) of a flow path. The flow path includes a switch, such as a bi-stable fluidic switch, for reversing the direction of the flow in the vortex chamber. The flow path may include multiple vortex chambers, and the device may include multiple flow paths. A hardened insert in the outlet of the vortex chamber resists erosion. This device generates backpressures of short duration and slower frequencies approaching the resonant frequency of the drill string, which maximizes axial motion in the drill sting and weight on the bit. Additionally, fluid pulses produced by the tool enhance debris removal ahead of the bit.

Abstract: A vortex-controlled variable flow resistance device ideal for use in a backpressure tool for advancing drill string in extended reach downhole operations. The characteristics of the pressure waves generated by the device are controlled by the growth and decay of vortices in the vortex chamber(s) of a flow path. The flow path includes a switch, such as a bi-stable fluidic switch, for reversing the direction of the flow in the vortex chamber. The flow path may include multiple vortex chambers, and the device may include multiple flow paths. A hardened insert in the outlet of the vortex chamber resists erosion. This device generates backpressures of short duration and slower frequencies approaching the resonant frequency of the drill string, which maximizes axial motion in the drill sting and weight on the bit. Additionally, fluid pulses produced by the tool enhance debris removal ahead of the bit.