Abstract: An autonomous flow control device includes a valve assembly having a fluid inlet and a fluid outlet. A valve element is disposed between the fluid inlet and the fluid outlet. The valve element has a viscosity dominant flow path configured to provide a first flow resistance and an inertia dominant flow path configured to provide a second flow resistance that is greater than the first flow resistance such that when the viscosity of the fluid flowing therethrough is greater than a first predetermined level, the fluid follows the viscosity dominant flow path with the first flow resistance and when the viscosity of the fluid flowing therethrough is less than a second predetermined level, the fluid follows the inertia dominant flow path with the second flow resistance, thereby regulating the production rate of the fluid responsive to changes in the viscosity of the fluid.

Abstract: A system includes a compression spring having a latch sleeve, a piston rod including a groove section, and a ratchet assembly that progressively moves the piston rod in a downward direction. A latch collet on the latch sleeve sits on the groove section of the piston rod in a first position of the system. The latch collet locks a spring force of the compression spring as the ratchet assembly progressively moves the piston rod in the downward direction. The latch collet becomes unsupported from the groove section when the piston rod has progressively moved a predetermined distance, causing the compression spring to release and provide a push force that actuates a hydraulic valve from the first position to a second position.

Abstract: A downhole tool which allows the selective operation of a second fluid pressure activated tool below a first fluid pressure activated tool on a tool string in a well. The downhole tool has a piston sleeve moveable inside a cylindrical body between a first position in which a small flow area is provided through the tool and a second position in which a larger flow area is provided. The piston sleeve is held in the first position by a magnet and the first fluid pressure activated tool can be operated by increasing fluid pressure above the tool up to a cracking pressure level which matches the pulling strength of the magnet. Increasing fluid pressure to the cracking pressure therefore selectively moves the piston sleeve to the second position in which the second fluid pressure activated tool can be operated. The downhole tool is resettable.

Abstract: A fallback prevention valve apparatus, system and method is described. An electric submersible pump (ESP) fallback prevention system includes an ESP assembly positioned in a downhole well, the ESP assembly including production tubing extending between a centrifugal pump and a surface of the downhole well such that during operation of the ESP assembly production fluid flows upward from the centrifugal pump through the production tubing to the surface, the production tubing including a fallback valve actuatable by the flow of production fluid, the fallback valve actuatable between an open position, wherein production fluid flowing upward through the fallback valve actuates the fallback valve into the open position, and a closed position, wherein production fluid flowing downward through the fallback valve actuates the fallback valve into the closed position, the closed position blocking sand carried by the production fluid from falling into the centrifugal pump.

Abstract: A bottomhole assembly (BHA) having a shifting tool and housing for shifting an uphole-to-open sleeve of a sleeve of a shorter length downhole sleeve assembly to an open position, and optionally to a closed position. Sleeve-engaging elements of the BHA are coordinated to direct the sleeve-engaging elements into a tool-engaging profile of the sleeve, excluding other annular variations in the casing string. The BHA has an improved dual J-Mechanism situated between the shifting tool and housing to permit new additional shifting options which results in fewer overall shifting cycles of the BHA when used with the shift uphole-to-open, shorter-length sleeve assembly. The shortened sleeve assembly is incorporated into a casing string and is relatively short in length when compared with conventional sleeve assemblies.

Abstract: An inflow assembly for use in a subterranean well, which inflow assembly is arranged to prevent one or more fractions of the produced medium from entering the production tubing, comprises at least one chamber containing within it at least three floating/sinking elements, the chamber having an inlet/opening facing in the inflow direction into the chamber, and having an outlet that is open to flow directly from the inlet/opening without being blocked by the floating/sinking element when a desired medium is produced, where the middle one of the elements is arranged to block the outlet aperture from the chamber when undesired medium is produced, whilst the two other elements have the task of forming a movable floor and a movable ceiling in the chamber.

Abstract: An inflow assembly for use in a subterranean well, which inflow assembly is arranged to prevent one or more fractions of the produced medium from entering the production tubing, comprises at least one chamber containing within it at least three floating/sinking elements, the chamber having an inlet/opening facing in the inflow direction into the chamber, and having an outlet that is open to flow directly from the inlet/opening without being blocked by the floating/sinking element when a desired medium is produced, where the middle one of the elements is arranged to block the outlet aperture from the chamber when undesired medium is produced, whilst the two other elements have the task of forming a movable floor and a movable ceiling in the chamber.

Abstract: A downhole tool comprises a housing defining a flow path therethrough in an axial direction from an upper opening to a lower opening. A poppet valve is mounted within the housing. The poppet valve includes an upper member defining an upper chamber mounted in the flow path so that flow through the flow path flows around the upper member, and a valve seat mounted in the flow path with an opening therethrough. A valve poppet is mounted for longitudinal movement within the flow path between a closed position in which the valve poppet seats against the valve seat to block flow through the flow path and an open position in which the valve poppet is spaced apart from the valve seat to permit flow through the flow path. This can restrict/mitigate sand fall-back, e.g., with flow paths designed to prevent/mitigate sand fall-back and for protection of the poppet from sand/debris.

Abstract: A multi-function diverter tool is disclosed that allows positive-indication opening and closing of the tool in a downhole environment. The tool includes a first sleeve adapted to open outlet ports in the exterior surface of the tool body. The tool includes a second sleeve which is movable with respect to the first sleeve and is adapted to close the outlet ports when moved from an initial position to a second position.

Abstract: A heel-to-toe method and system for horizontal well treatments incorporates use of frac ball and sleeve in conjunction with biodegradable diverting agents.

Abstract: A pressure actuated inflow control device that includes: a housing having a wall within which a fluid passageway axially extends; a collapsible apparatus coupled to the housing and configured to change from an extended to a retracted configuration when subjected to a predetermined pressure; and an axially extending plug at least partially disposed within the fluid passageway and removable from the fluid passageway; wherein, when the collapsible apparatus is in the extended configuration, the plug is disposed within the fluid passageway at a first position relative to the housing to restrict fluid flow through the fluid passageway; and wherein, when the collapsible apparatus changes to the retracted configuration, the plug is either: moved to a second position relative to the housing to allow fluid flow through the fluid passageway; or capable of moving from the first position to allow fluid flow through the fluid passageway.

Abstract: A sand bridge inducer for a downhole tool can include a wall defining a main opening therethrough and one or more angled passageways defined through the wall such that the one or more angled passageways open from a radially inward opening and traverse axially downward through the wall toward a radially outward opening.

Abstract: A frac sleeve assembly and method of operation. The frac sleeve assembly includes a ball seat that retains a frac ball. The ball seat moves within a sleeve. The sleeve includes a profile that separates the first half and the second half to allow passage of the frac ball through the ball seat when the ball seat moves within the sleeve. Alternatively, the ball seat has a ring for receiving the frac ball and the sleeve has a protrusion that selectively engages a shifting pin to move the ring with respect to a ridge to release the ball from the ball seat when the ball seat moves within the sleeve.

Abstract: A hydraulic port collar includes a housing having one or more housing ports. The hydraulic port collar includes a port collar bore disposed within the housing forming an inner surface of the housing. The hydraulic port collar includes a sliding sleeve disposed within the port collar bore. The sliding sleeve has a sliding sleeve inner surface and a sliding sleeve outer surface. The hydraulic port collar includes a dissolvable or fragmentable landing seat radially aligned with and abutting the sliding sleeve inner surface.

Abstract: Examples of the present disclosure relate to systems and methods for utilizing an inner diameter of a tool for jet cutting and hydraulically setting packer.

Abstract: A method for recovering oil from a hydrocarbon-bearing reservoir using pressure pulse injections of an aqueous salt solution is provided. The aqueous salt solution includes one or more salts suitable for enhancing oil recovery in carbonate reservoirs and has a salinity in the range of about 5,000 parts-per-million (ppm) total dissolved solids (TDS) to about 7,000 ppm TDS. The aqueous salt solution may be injected into a reservoir using continuous or periodic pressure pulse injections.

Abstract: A technique provides enhanced control over a variety of hydraulically actuated devices, e.g. flow control valves. A hydraulic control module is placed in hydraulic communication with an actuator of a hydraulically actuated device. The hydraulic control module comprises features which prevent hydraulic locking of the system. Additionally, the control module may comprise metering features to enable metered flow of actuating fluid. The features may include valves, mini-indexers, flowline configurations, or other features which maintain the ability to shift the hydraulically actuated device and/or provide metering of the actuating fluid.

Abstract: The present invention relates to acirculation subassembly (circsub) for incorporation in a drill pipe. The circsub has a flow through condition in which the circsub allows fluid to flow through a bore of the circsub and does not allow fluid communication between the bore of the circsub and an annulus located outside the drill pipe, a partial bypass condition in which the circsub allows fluid to flow through the bore of the circsub and allows fluid communication between the bore of the circsub and the annulus, and a full bypass condition in which the circsub does not allow fluid to flow through the bore of the circsub and allows fluid communication between the bore of the circsub and the annulus. An actuator is provided to change the circsub between conditions under the control of a controller.

Abstract: A bypass assembly for a packer includes a first adapter including a first central bore, a first radial opening communicating with the first central bore, and first axial openings prevented from fluid communication the first central bore. The bypass assembly includes a second adapter including a second central bore, a second radial opening communicating with the second central bore, and second axial openings prevented from fluid communication with the second central bore. The bypass assembly includes a tubular coupled to the first central bore and the second central bore, the tubular being configured to extend through the packer. A first flowpath is defined from the first radial opening through the tubular and the second radial opening, and a second flowpath is defined through the first axial openings, between the tubular and the packer, and through the second axial openings.

Abstract: A flow diverter is provided having a first sub member, a second sub member, a third sub member connected in series and a piston, a spring, and a sleeve member. The sleeve member is removeably disposed within the second sub member. The spring concentrically surrounds at least a portion of the piston and the spring are slidably disposed within the first sub member with the piston further slidably disposed within the second sub member and at least a portion of the third sub member. A drilling fluid having a first predetermined pressure passes through the flow diverter. The drilling fluid having a second predetermined pressure moves the piston until at least a portion of the drilling fluid passes through bypass ports formed in the piston, sleeve member, and second sub member and out of the flow diverter, thus controlling the pressure of the drilling fluid.

Abstract: An isolation valve system, method, and apparatus are provided that can isolate a wellbore and prevent fluids from exiting the well and prevent seawater from entering the well. The system can be a two-part design in some embodiments where a shear sub is selectively interconnected to a body via shearing screws. A sufficient force on the shear sub destroys the shearing screws and the shear sub is removed from the body. This movement rotates an actuator on the body, which in turn rotates a valve in the body to provide the isolating function during routine operation of a wellbore or during an emergency.

Abstract: A valve assembly comprises an actuation fluid inlet, an actuation fluid outlet and a valve member moveable between a closed position in which the actuation fluid outlet is closed, and an open position in which the actuation fluid outlet is opened. A locking arrangement is provided for locking the valve member in its closed position, wherein the locking arrangement is operable in response to a first predetermined fluid pressure event associated with at least the actuation fluid inlet to release the locking arrangement to permit the valve member to be moved to its open position in response to a second subsequent predetermined fluid pressure event associated with at least the actuation fluid inlet.

Abstract: A technique enables mechanical control of a directional valve. The technique may utilize a system comprising a directional valve which is mechanically actuatable between a plurality of flow positions. The directional valve is mechanically coupled with an indexer mechanism. The indexer mechanism may be shifted to a plurality of desired indexer positions defined by a cam track. As the indexer mechanism is shifted between indexer positions, the mechanical link between the indexer mechanism and the directional valve mechanically shifts the directional valve to selected flow positions of the plurality of flow positions.

Abstract: A safety valve features a flow tube operated flapper for the normal open and closed positions that can be obtained with one or two control lines to a principal operating piston. Pressure applied to the piston moves the flow tube to rotate the flapper open behind the flow tube. Release of pressure to the principal piston allows a closure spring to return the flow tube up to let the flapper close. A secondary piston can drive the flow tube with applied pressure through a control line. Cycling the applied pressure in combination with an indexing mechanism allows the flapper to be locked open and then released to normal operation. The pistons act as backup for each other as they both drive the flow tube. The flow tube has a clearance fit to the body in the locked open position to exclude debris from the flapper.

Abstract: An overtensioning fastening tool to maintain control of oil and gas equipment and prevent migration upon failure. The overtensioning fastening tool is comprised of one or more flapper components, housed in a primary enclosure, a hydraulic deployment system and/or electric deployment system, housed in a secondary enclosure, a sensor, and a manual activation component. The overtensioning fastening tool is designed to grip and hold equipment and tooling, such as cables.

Abstract: A hydraulic gentle vibration speed-enhancing drilling tool has an upper joint, a power assembly, a flow regulating valve assembly and a force transmission assembly. The upper end of an outer shell of the power assembly is in threaded connection with the upper joint of the drilling tool, at the lower end thereof, internal steps having outer octagonal structure are arranged to limit the lower joint; a middle section of the lower joint is of outer octagonal structure, with the lower end in threaded connection with an adapter; and the power assembly is of turbine set structure or screw-type mud motor structure for producing driving force under the action of hydraulic force and driving an upper rotating shaft. The upper rotating shaft is arranged on a load bearing ring, and the lower end thereof is in threaded connection with a lower rotating shaft.

Abstract: A system includes a flow restrictor assembly configured to be coupled to an annular structure having a central bore. The flow restrictor assembly includes one or more adjustable segments configured to move relative to the annular structure between a retracted position in which the one or more adjustable segments do not extend into the central bore and an extended position in which the one or more adjustable segments extend into the central bore to reduce a cross-sectional flow area of the central bore by between approximately 5 to 95 percent to restrict fluid flow through the central bore.

Abstract: A method for analyzing material wear in a hydrocarbon production environment is disclosed. The method includes the steps of preparing a sample of material to be disposed proximate the hydrocarbon production environment; selecting a placement location for the sample of material, wherein the placement location is in fluid communication with a fluid flow for which the impact of the fluid flow on the sample of material is to be tested; disposing the sample of material in the placement location for a pre-determined amount of time; allowing the sample of material to be exposed to the fluid flow; retrieving the sample of material from the placement location after the pre-determined amount of time has passed; and analyzing the sample of material for wear caused by the hydrocarbon production environment.

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

Abstract: A landing string includes a valve having a valve member mounted within a flow path extending through the landing string, and a valve control system for use in operating the valve to move the valve member between open and closed positions to control flow along the flow path. The valve control system is reconfigurable between a first configuration in which the valve is operated or controlled under a fail-as-is (FAI) mode of operation, and a second configuration in which the valve is operated or controlled under a fail-close (FC) mode of operation.

Abstract: An automatic tubing drain for rotary pumps automatically closes when the pump starts and opens when the pump stops using reactive torque generated by the pump.

Abstract: The present invention generally relates to an isolation valve with debris control. In one aspect, an isolation valve for use as part of a casing string is provided. The isolation valve includes a housing having a bore and a valve cavity. The isolation valve further includes a valve member movable between a first position in which the valve member obstructs the bore of the housing and a second position in which the valve member is disposed in the valve cavity. Further, the isolation valve includes a flow tube configured to allow movement of the valve member between the first and second positions. Additionally, the isolation valve includes an engagement assembly adapted to engage the flow tube to substantially prevent debris from entering the valve cavity when the valve member is in the second position. In another aspect, a method of operating an isolation valve in a wellbore is provided.

Abstract: A cementing port collar has an opening sleeve biased from a closed position to an opened position relative to the collar's exit port, and a first restraint temporarily holds the opening sleeve closed. The collar also has a closing sleeve biased from an opened position to a closed position, and a second restraint temporarily holds the closing sleeve opened. During cementing, the first restraint is electronically activated with a first trigger to release the opening sleeve opened so cement slurry can pass out of the collar's exit port to the borehole annulus. When cementing is completed, the second restraint is electronically activated with a second trigger to release the closing sleeve closed to close off the collar to the borehole so the cement can set. The restraints can include bands of synthetic fiber, which are burned by fuses activated by a controller of the collar responding to passage of RFID tags.

Abstract: A wellbore subassembly includes a device having a production flow path toward a production tubing. The production flow path can include a superhydrophobic coating for restricting the production of an unwanted fluid towards the production tubing.

Abstract: Disclosed is a safety valve with redundant operators or systems. One safety valve includes a piston bore in fluid communication with a first control line via first control line port and a second control line via a second control line port, the first and second control lines conveying hydraulic fluid pressure to the piston bore. First and second piston assemblies are movably arranged within the piston bore and the second piston assembly includes a transition member coupled thereto. A flow tube is arranged adjacent the transition member and moves axially within a flow passage defined in the safety valve in response to the movement of the transition member. A valve closure device moves between an open position and a closed position restricts fluid flow through the flow passage when in the closed position, the flow tube being adapted to shift the valve closure device between open and closed positions.

Abstract: A steam operated flow control device and method is disclosed. In one mode, the flow control device enables steam to be injected into a subterranean formation region containing hydrocarbons. In another mode, the flow control device enables the hydrocarbons to be produced from the subterranean formation to the surface. The flow control device includes a piston disposed between a housing and a mandrel having aligned ports, which slides between a first position where one set of ports align with the ports in the housing and the mandrel and a second position where another set of smaller ports align with the ports in the housing and mandrel. The piston is operated by a bellows having a chamber which contains a fluid. The fluid responds to temperature and/or pressure variations.

Abstract: Certain aspects and embodiments of the present invention are directed to a semi-autonomous insert valve. The semi-autonomous insert valve includes a body, a closure mechanism coupled to the body, an autonomous actuation mechanism coupled to the body, and a control system disposed in the body. The body engages an inner wall of a subsurface safety valve and causes a subsurface safety valve closure mechanism to open, allowing fluid to flow toward the surface of the wellbore. The closure mechanism selectively allows fluid to flow toward the surface of the wellbore. The autonomous actuation mechanism actuates the closure mechanism independently from a subsurface safety valve actuation mechanism that actuates the subsurface safety valve closure mechanism. The control sub-system includes one or more transceiving devices that can wirelessly communicate signals. The control sub-system closes the closure mechanism in response to losing signal communication between the transceiving devices and a signal source.

Abstract: Disclosed are shifting tools for opening and closing shifting sleeves. A disclosed completion system includes a completion string having a shifting sleeve movably arranged therein, a service tool configured to be arranged at least partially within the completion string and including a shifting tool having one or more shifting keys configured to mate with the shifting profile. When the shifting keys locate and mate with the shifting profile, an axial load applied on the service tool axially moves the shifting sleeve. If the shifting key is misaligned with a complementary shape of the shifting sleeve, a lower detent housing retracts toward an upper detent housing against a force of a detent spring to allow the shifting keys to retract while maintaining a radially outward force. If an axial load is removed, the housings are automatically retracted by a return spring, causing the shifting keys to disengage.

Abstract: A subsea power module includes an outer pressure compensated vessel defining an interior chamber and one or more heat generating electrical components disposed within the interior chamber. The outer pressure compensated vessel is configured to maintain a pressure within the interior chamber substantially the same as an ambient pressure outside the outer pressure compensated vessel. Each of the electrical components may be disposed within an inner chamber of a pressure vessel disposed within the interior chamber of the outer pressure compensated vessel. Each of the one or more heat generating electrical components is configured to transfer heat generated within the interior chamber of the outer pressure compensated vessel through the wall defining the interior chamber to a fluid, such as seawater, surrounding the outer pressure compensated vessel.

Abstract: A downhole assembly for tool actuation using pressure delay is provided. The downhole assembly can include a chamber, a pressure path, a pressure damper, a pressure source, and a member. The pressure path can be positioned between first and second ends of the chamber. The pressure damper can reduce a rate at which pressure is communicated in the pressure path. Pressure from the pressure source can be communicated to the first end of the chamber and the second end of the chamber at different rates. The member can be positioned in the chamber between the first end and the second end. The member can actuate a downhole tool in response to a pressure difference between the first end and the second end. The pressure difference can result from a difference in between the first rate and the second rate.

Abstract: Method and apparatus for suppressing cable dynamics in a device towed in water. The apparatus includes at least one section for suppression of motion, wherein the at least one section includes an axial motion suppression section; and the axial motion suppression section comprising equipment for the attenuation of axial vibrations in an electro-mechanical cable. The equipment is configured to produce a digressive stiffness curve.

Abstract: Systems and methods quickly regulate hydraulic fluid pressure to meet hydraulic fluid demands in subsea equipment over long umbilicals. A hydraulic power unit includes a reservoir and a pump for pumping hydraulic fluid from the reservoir into a fluid supply line to subsea equipment. A supply-side module located downstream of the hydraulic power unit includes a circulation pump in communication with the supply line for circulating hydraulic fluid in a circuit including the fluid supply line and a fluid return line. A demand-side module is located upstream of the subsea equipment and includes a diverter valve for opening or closing the circuit. Adjustments can be made to the circulation pump and the diverter valve such that hydraulic fluid is circulated through the circuit. The pressure of the supply-side module is greater and does not exceed twice than the pressure of the demand-side module.

Abstract: There is provided a downhole umbilical release assembly comprising a guillotine arrangement provided by a guillotine alignment sub (12) and a guillotine mandrel (16). The guillotine alignment sub has a first edge (27) over which an umbilical is positioned in a wellbore string. The guillotine mandrel is positioned radially outwardly of the guillotine alignment sub and is arranged to move longitudinally with respect thereto. The guillotine mandrel has a second edge (29) that is arranged to pass over the first edge (27) of the guillotine alignment sub during longitudinal movement of the guillotine mandrel relative to the guillotine alignment sub. This severs an umbilical positioned between the two edges (27,29).

Abstract: A multi-acting downhole tool arrangement (100), (400), (500) includes a tubular (102) and an actuatable sliding member (104), (404), (504) radially disposed relative to the tubular (102) in a radial sealing relationship. The tubular (102) and the member (104), (404), (504) are arranged relative to one another in a non-slidable first configuration. The sliding member (104), (404), (504) and the tubular (102) cooperate to define a chamber 116 therebetween. At least a pair of seals (108), (110), (410), (446) delimits the chamber (116). A first one (110), (446) of the pair of seals is a degradable seal. Upon actuation of the sliding member (104), (404), (504), the sliding member (104), (404), (504) slides in a first direction relative to the tubular (102) to a second configuration where the degradable seal (110), (446) is exposed to a condition that degrades the degradable seal (110), (446).

Abstract: A well tool having an actuator sleeve in a housing. The actuator sleeve has an internal shifting tool engaging profile. The tool has an actuator in the housing that is responsive to a remote signal to change from an unactuated state to an actuated state and shift the actuator sleeve from a first position to a second position. A fluid chamber in the housing is defined between the actuator sleeve and the actuator. The fluid chamber contains a fluid to communicate movement of the actuator to the actuator sleeve.

Abstract: The present invention relates to an inflow control device for controlling the flow of fluid into a tubular deployed in a wellbore comprising coupling between joints of tubulars. The inflow control device is mounted transversely through the coupling in any inflow can control devices the initial condition fluid flow between the exterior and interior of the tubular is prevented. As sufficient pressure is exerted upon the inflow control device from the interior of the tubular the inflow control device is actuated to allow fluid flow between the interior and exterior the tubular. A nozzle in the inflow control device allows fluid to pass at a preset rate.

Abstract: A wireline retrievable injection valve for an oil or gas well has an internal valve that is initially moved to open a flapper safety valve and also opens to allow fluid flow through the valve. The internal valve includes a sleeve that opens the flapper safety valve and shields the flapper safety valve from fluid. In this manner the flapper valve is protected from being caused to “flutter” or “chatter” due to pressure variations in the fluid flow, which may damage the seat.

Abstract: Devices, systems and methods are disclosed for re-directing fluid flow from the interior of tubing placed in a well to the exterior of the tubing by use of selectively actuatable valves operable by engagement of a plug on a plug seat. The devices, systems, and methods disclosed may provide a flowback bypass for the flow of fluids around obstructions in the tubing when those obstructions occur at a predicted location within the tubing. The systems, devices and methods may also include a locking system operable by, among other things, plug and plug seat valves, and such locking system may be used to prevent opening of the flowback bypass until after a predetermined event has occurred.

Abstract: A system comprising a control valve comprising a flapper either activated or inactivated, when activated the flapper may be closed or open and, when inactivated the flapper is open, a first sleeve transitional from a first to a second position, and a second sleeve transitional from a first to a second position, when the first and second sleeves are in the first position, the flapper is activated, when the first sleeve is in the second and the second sleeve is in the first position, the flapper is inactivated, when the first and second sleeves are in the second position, the flapper is activated, the application of pressure to the first sleeve via a first member transitions the first sleeve from the first to the second position, and the application of pressure to the second sleeve via a second member transitions the second sleeve from the first to the second position.

Abstract: A replaceable antenna assembly for use with a piston accumulator configured for supplying fluid to a hydraulic cylinder is provided. The antenna assembly includes a hollow manifold for flow of fluid and an antenna connected into or onto the manifold for emitting and receiving electromagnetic waves. The hollow manifold is connectable to and configured to be in fluid communication with both the piston accumulator at one end and a pressure line at the other end. The pressure line is connectable to an external high pressure gas bank. The antenna assembly further includes at least one first bore for transferring signals to and from the antenna and at least two fluid channels symmetrically displaced around the circumference of the antenna, thereby ensuring that most of, or all, fluid flows on the radial outside of the antenna during use.