Abstract: A ball dropper assembly includes a main body, a sealing piston, and a magazine assembly. The main body includes a main bore, angle bore, and transverse bore formed therethrough. The transverse bore is fluidly coupled to the main bore through the angle bore. The sealing piston is positioned within the transverse bore. Seal rings are positioned between the main body and the sealing piston on either side of the angle bore. The magazine assembly includes a magazine body and a carrier piston. The magazine body is mechanically coupled to the main body. The carrier piston has a carrier hole formed therein and is mechanically coupled to the sealing piston.

Abstract: A scraper launcher includes a body having a rim and a trap door having a first surface and a second surface, where an interfacing portion of the second surface interfaces with an interfacing surface of the rim when the trap door is closed against the rim. A seal is provided between the interfacing portion of the trap door and the interfacing surface of the rim. The scraper launcher also includes a sealant injection system with sealant passages formed through the scraper launcher, fluidly communicating an exterior of the scraper launcher to an interior of the scraper launcher, and an injection fitting in communication with the sealant passages.

Abstract: A self-erecting launcher assembly includes a mobile unit, and a magazine positioned in a receptacle of the mobile unit. The magazine includes a plurality of drones. A rail unit is secured to the mobile unit and moves between a closed position and an elevated position. A platform may be secured to the rail unit and is movable in an upward direction and a downward direction along a length of the rail unit. The platform is movable when the rail unit is in its elevated position. The magazine or the plurality of drones may be positioned on the platform, such that the platform moves the magazine or the plurality of drones from the mobile unit to at least one wellhead. A manipulator arm is secured to the platform and selects a drone of the plurality of drones and delivers the selected drone into a lubricator positioned at the wellhead.

Abstract: Devices and methods are provided for reducing or removing condensation from compressed air.

Abstract: An airgun has a high pressure reservoir for providing a pressurized motive gas to a breech to fire a projectile. A regulator is intermediate the high pressure reservoir and a downstream firing pressure reservoir for providing a consistent regulated pressure of the motive gas in the firing pressure reservoir. The airgun includes a bypass line for selectively connecting the high pressure reservoir to the firing pressure reservoir, independently of the regulator. Thus, an operator can select a firing of the airgun with either a regulated gas pressure in the firing reservoir or the pressure of the high pressure reservoir.

Abstract: A vertical barrel of an internal diameter to receive a pig having a selected uncompressible diameter, a reducer to compress the pig to a compressed diameter and a fluid system to introduce fluid pressure into the upper end of the barrel to drive the pig through the reducer.

Abstract: A valve, such as a ball valve, can include a noise attenuation assembly to control fluid expansion through the valve and provide noise abatement. The valve can include a valve body and a valve stem and the noise attenuation assembly can include a flow control body and a trim body. The flow control body can be coupled to the valve stem and the flow control body can be configured to selectively permit fluid flow through the valve body in an axial direction. The trim body can include a plurality of channels to control fluid expansion during fluid flow through the valve body. The trim body can be engaged with the flow control body at first and second mounting structures of the flow control body to secure the trim within a fluid pathway of the flow control body.

Abstract: It is a pig launcher (1) comprising a pig magazine (2), launcher mechanism (3) and a connector (7) being connectable to a fluid flow line. The pig magazine (2) is able to hold a number of pigs arranged side by side, control lines (4) being connected to the pig magazine in such a way that each control line (4) is able to provide control fluid to manipulate a pig. The pig launcher further comprises a pig selector (5) being able to receive source control fluid from one control fluid source line (9) and to channel the control fluid to one of a number of control lines (4) being connected to the pig selector, thereby being able to launch one of the number of pigs by means of the control fluid.

Abstract: The invention relates to systems for producing oil and hydrocarbons in general, in deep water, using subsea wells and apparatus which are interconnected in a drainage and production system. In this context, the invention relates to a mandrel multiplying device (1a, 1b, 1c, 1d, 1e, 1f) suitable for providing additional points between pieces of subsea apparatus, the device comprising a connector (2) for coupling to a mandrel of a subsea apparatus (8, 9), and at least two mandrels (3, 4, 5) suitable for providing points for connection to subsea lines (J1, J1?, J1?, J2, R1, R2, A1, A2, A3) which are connected to other pieces of subsea apparatus (8, 9) or to a production unit (13).

Abstract: A ball dropper assembly includes a main body, a sealing piston, and a magazine assembly. The main body includes a main bore, angle bore, and transverse bore formed therethrough. The transverse bore is fluidly coupled to the main bore through the angle bore. The sealing piston is positioned within the transverse bore. Seal rings are positioned between the main body and the sealing piston on either side of the angle bore. The magazine assembly includes a magazine body and a carrier piston. The magazine body is mechanically coupled to the main body. The carrier piston has a carrier hole formed therein and is mechanically coupled to the sealing piston.

Abstract: A computer implemented method may include executing a first simulation test for testing a device under test (DUT) and a corresponding test environment; saving a snapshot image of the DUT and of the corresponding test environment upon completion of initialization actions included in the first simulation test to configure the DUT; compiling a DUT part of a second simulation test into the saved snapshot image of the DUT to obtain a restore image for the DUT; loading the restore image of the DUT and restoring the snapshot image of the test environment; loading a test environment part of the second simulation test; and executing the second simulation test on the DUT and corresponding test environment.

Abstract: A system for identifying an anomaly in flow meter proving equipment includes four detectors D1, D2, D3, and D4. A data acquisition and monitoring system is configured to signals from D1, D2, D3, and D4 to measure flow volumes between D1 and D3 as a measured volume Va, between D2 and D4 as a measured volume Vb, between D2 and D3 as a measured volume Vc, and between D1 and D4 as a measured volume Vd. The data acquisition and monitoring system calculates Va+Vb?Vc?Vd plus a max uncertainty as an upper range value and Va+Vb?Vc?Vd minus the max uncertainty as a lower range value. The data acquisition and monitoring system identifies an anomaly in response to the upper range value being less than zero or the lower range value being greater than zero and initiates recalibration of the prover in response to the identifying of the anomaly.

Abstract: An apparatus and related method are provided for loading a pig into a pipeline. The apparatus includes a tubular reducer, a rigid member including a pig-engaging surface, and a guide member slidingly engaged by the rigid member to permit axial movement, while limiting radial movement, of the rigid member in relation to the reducer. In use, when the reducer is aligned concentrically with the pipeline end with the front end of the reducer bearing axially, either directly or indirectly, against the pipeline end, and the pig-engaging surface is disposed axially rearward of the reducer, increased tension in the cable pulls the rigid member axially forward relative to the pipeline, whereupon the attached pig-engaging surface pushes the pig through the reducer and into the pipeline interior.

Abstract: A subsea well intervention cap is provided. The subsea well intervention cap includes a frame, a first clamp segment coupled to the frame and configured to be fitted over a horizontally oriented flowpath of a subsea well equipment component, and a second clamp segment having a rim segment configured to interface with the first clamp segment, wherein the second clamp segment is movable with respect to the first clamp segment. The subsea well intervention cap also includes an actuation mechanism coupled to the frame that actuates the second clamp segment in a vertically upward direction and in an axial direction with respect to the frame toward the first clamp segment. The subsea well intervention cap is lightweight and able to be installed on subsea well equipment using a standard remote operated vehicle (ROV).

Abstract: A pig diverter comprises a hollow housing having a flowline inlet port, a flowline outlet port, a pig entry opening, and a pig exit opening, all communicating with the interior of the housing. A tubular pig holder enclosed by the housing is pivotable between a receiving position and a launching position. In the receiving position, the pig holder is aligned with the pig entry opening to receive a pig and effects fluid communication between the pig entry opening and the flowline outlet port. In the launching position, the pig holder is aligned with the pig exit opening to launch a pig and effects fluid communication between the flowline inlet port and the pig exit opening.

Abstract: A method is provided for inhibiting formation of a gas hydrate in a pipeline or removing a gas hydrate existing in a pipeline. The method can comprise injecting a foam composition into a fluid in the pipeline to inhibit formation of the gas hydrate in the pipeline, prevent gas hydrate formation in the pipeline, or remove the gas hydrate from the pipeline.

Abstract: A pig trap of this disclosure may include one or more injectors or nozzles located along a sidewall of the barrel and oriented to deliver a jet of fluid toward a back side of a vertical member of a pig or tool. The nozzle may be part of an assembly that includes a longitudinally extending pipe having a flat-profile flange at an inlet end, a curved-profile flange at the nozzle end, and a bend in between the two ends. When the assembly is installed in a sidewall opening of a pig trap, the nozzle delivers a jet of fluid toward the back side of a vertical member of the pig. A leak path may be provided through flanges or formed between the sidewall opening and a periphery of the curved-profile flange. Launch forces of more than 10 to 15 times that of a conventional launcher may be achieved.

Abstract: A drone conveyance system for deploying drones into an oil or gas wellbore is described. The system includes a platform, a drone magazine, a platform receiver, a conveyance, and a wellhead receiver. A drone magazine contains a plurality of the drones and selectively releases/feeds the drones into the platform receiver. More than one drone magazine, each containing different drone types, may supply drones to the platform receiver such that different drones may be ordered for disposal into the wellbore. The platform receiver prepared the drones to be moved from the platform to the wellhead by the conveyance. The wellhead receiver accepts the drones from the conveyance and prepares each received drone for dropping into the wellbore via the wellhead.

Abstract: A drone conveyance system and a wellhead receiver for deploying drones into an oil or gas wellbore includes a platform, a drone magazine, a platform receiver, a conveyance, and a wellhead receiver. The wellhead receiver prepares the drone to be inserted into the wellbore via the wellhead. Preparation of the drone to be inserted into the wellbore includes adjusting the physical conditions surrounding the drone to approximate the physical conditions in the wellbore. The preparation may be performed using fluid inputs and outputs connected to a compartment of the wellhead receiver. Other preparation processes may also take place in the wellhead receiver such as assuring the appropriate drone is being inserted, that the drone has been programmed appropriately, that safety devices have been deactivated and charging an onboard power supply of the drone.

Abstract: The invention provides an apparatus for dropping at least one object into a wellbore tubular string. The tool comprises a mandrel having an inlet and an outlet. The tool also comprises a movable member comprising a bore for receiving the at least one object. The member is movable relative to the mandrel between a first condition in which the bore is not aligned with the mandrel outlet and a second condition in which the bore is aligned with the mandrel outlet.

Abstract: An apparatus and related method are provided for loading a pig into a pipeline. The apparatus includes a tubular reducer, a rigid member for attachment to a cable and including a pig-engaging surface, and a guide member slidingly engaged by the rigid member to permit axial movement, while limiting radial movement, of the rigid member in relation to the reducer. In use, when the reducer is aligned concentrically with the pipeline end with the front end of the reducer bearing axially, either directly or indirectly, against the pipeline end, and the pig-engaging surface is disposed axially rearward of the reducer, increased tension in the cable pulls the rigid member axially forward relative to the pipeline, whereupon the attached pig-engaging surface pushes the pig through the reducer and into the pipeline interior.

Abstract: A pig wrap has an elongated non-permeable wrap and a holding ring. The elongated non-permeable wrap has a first end that is closed and a second end that is attached to the holding ring. The holding ring retains the elongated non-permeable wrap in such a manner that the elongated non-permeable wrap is capable of encompassing a pipeline pig as it passes through the holding ring. The holding ring is positionable at an exit of a pig trap or launcher.

Abstract: A pigging system has an apparatus for launching one or more pigs into a process flow. The apparatus has a housing with a chamber, an inlet, and an outlet. The inlet receives the one or more pigs into the chamber and is sealable. The outlet is in sealed communication with the process flow and passes the one or more pigs out of the chamber to the process flow. A portion of the chamber is in communication with the process flow. A guide disposed in the chamber guides the one or more pigs in the chamber, and an actuator mechanically feeds the one or more pigs guided by the guide to the outlet.

Abstract: A pipeline pig launching device has a tubular body that accommodates a set of pipeline pigs arranged in series, such that respective chambers art defined within the body in which to apply launch pressure behind each pig. The body has an open end through which pigs of the set may be launched in succession and a closed end opposed to the open end. A fluid inlet communicates with one of the chambers defined between the closed end and a pig nearest to that closed end. A passageway communicates with another fluid inlet that passageway extending through at least one pig to one or more other chambers defined between successive pigs of the set.

Abstract: An apparatus for retrieval of a pipeline pig from a discharge outlet of a pipeline includes a recovery tank with an upward-facing recovery opening, attached to an adjustable height support frame. The recovery tank is positioned below the discharge outlet, and the height of the support frame adjusted to hold the recovery opening of the tank as close as possible to the discharge outlet, to receive the pig and related fluid or solid discharge when the outlet is opened. Fluid and flowable solids recovered in the recovery tank can be evacuated from an extraction port. Multiple secondary environmental protections can optionally be used as well, including a secondary containment tray, side shields extending upwards from the recovery opening, or a cover to close the tank.

Abstract: A pig trap of this disclosure may include one or more injectors or nozzles located along a sidewall of the barrel and oriented to deliver a jet of fluid toward a back side of a vertical member of a pig or tool. The nozzle may be part of an assembly that includes a longitudinally extending pipe having a flat-profile flange at an inlet end, a curved-profile flange at the nozzle end, and a bend in between the two ends. When the assembly is installed in a sidewall opening of a pig trap, the nozzle delivers a jet of fluid toward the back side of a vertical member of the pig. A leak path may be provided through flanges or formed between the sidewall opening and a periphery of the curved-profile flange. Launch forces of more than 10 to 15 times that of a conventional launcher may be achieved.

Abstract: A pipe pig for travelling along the bore of a pipe, the pipe pig comprising a tubular body extending along a longitudinal axis between a first end and a second end, and a plurality of discs extending radially from the longitudinal axis. At least one of the discs is a sensor disc that includes a plurality of electromagnetic sensors disposed therein.

Abstract: A ball trap screen for use with “T” type ball traps having a ball trap extension in which the ball trap screen includes a cone shaped inlet; an elbow, at least a portion of which includes a substantially planer solid area; a first screen section extending between the cone shaped inlet and the elbow; and a second screen section extending from the elbow into the ball trap extension; wherein at least a portion of the cone shaped inlet includes a cone solid blocking element, the first screen section includes a first solid screen blocking element and the second screen section includes a second solid screen blocking element. A method of enhancing the movement of the cleaning ball through the ball trap by blocking portions of a ball trap screen deployed within a ball trap housing so as to modify the fluid flow through the ball trap.

Abstract: Embodiments of the present disclosure include a pig ramp for receiving and supporting a pig in a pig receiver includes a frame portion having an inner diameter, the inner diameter of the ring being larger than an outer diameter of a pig. The pig ramp also includes one or more ramp segments extending longitudinally away from the frame portion, the one or more ramp segments being coupled to a back side of the frame portion at a lower portion and positioned to receive and support the pig when positioned thereon to elevate the pig above a bottom of a tubular.

Abstract: A tool designed for manipulation by an operator from a safe position out of line with the pig receiver opening in case an equipment failure or inadvertent opening of the trap before complete depressurization thereof should cause the pig to eject from the open end of the receiver. The tool features two main components, primarily a reaching assembly of substantially linear configuration having an elongated shape whose length runs along a first longitudinal axis, which lies generally parallel with a central longitudinal axis of the trap barrel during use of the tool, and support assembly that projects laterally from the reaching assembly in a direction generally perpendicular thereto so as to extend along a transverse axis that extends radially of the longitudinal axis.

Abstract: A valve body with an integral bypass includes a primary valve body portion defining a primary internal surface, the primary internal surface defining a primary bore extending through the primary valve body portion from a primary upstream end to a primary downstream end; and the bypass seamlessly integrated with the primary valve body portion, the bypass defining a bypass internal surface, the bypass internal surface defining a bypass bore, the bypass bore comprising a bypass upstream bore and a bypass downstream bore, the bypass upstream bore extending through the primary upstream end of the primary valve body portion, the bypass downstream bore extending through the primary downstream end of the primary valve body portion, the bypass internal surface seamlessly intersecting the primary internal surface at the primary upstream end and the primary downstream end.

Abstract: Disclosed herein is a condenser tube cleaning apparatus. The condenser tube cleaning apparatus can stably circulate and collect a large number of cleaning balls to efficiently remove foreign substances accumulated in a condenser unit.

Abstract: Some embodiments are directed to a method for guiding a high-pressure cleaning device for cleaning the inside of heat exchanger tubes, wherein the human eye has been replaced by an acquisition device, enabling to obtain images, making the automatic detection of tubes to be cleaned possible, with the possibility of remote visualization.

Abstract: Embodiments of the present disclosure include a pig ramp for receiving and supporting a pig in a pig receiver includes a frame portion having an inner diameter, the inner diameter of the ring being larger than an outer diameter of a pig. The pig ramp also includes one or more ramp segments extending longitudinally away from the frame portion, the one or more ramp segments being coupled to a back side of the frame portion at a lower portion and positioned to receive and support the pig when positioned thereon to elevate the pig above a bottom of a tubular.

Abstract: Embodiments of the present disclosure include a pig ramp for receiving and supporting a pig in a pig receiver includes a frame portion having an inner diameter, the inner diameter of the ring being larger than an outer diameter of a pig. The pig ramp also includes one or more ramp segments extending longitudinally away from the frame portion, the one or more ramp segments being coupled to a back side of the frame portion at a lower portion and positioned to receive and support the pig when positioned thereon to elevate the pig above a bottom of a tubular.

Abstract: A pig handling device has a housing, a cavity found in the housing in which a pig can be received, a connection by means of which the cavity is connectable to a processing system, the connection suitable for allowing the pig to pass through, and a handling element that is arranged in the cavity, influences the mobility of the pig in the cavity, and has a base element and a functional element. The base element has a first surface, and the functional element is connected to the base element in the cavity and has a second surface. The arrangement improves cleanability in that the handling element has a concavely curved transition surface arranged between the first surface and the second surface and having a core curvature region, and in that the base element and the functional element are bonded to one another outside of the core curvature region.

Abstract: A ball launcher has a body and a ball conveyor. The body has a sidewall defining axial bore, an attachment for attaching to a tubing string, and at least one radial port that provides access though the sidewall to the axial bore. The ball conveyor is carried by the body adjacent to an associated radial port. The ball conveyor comprises an inner bore in communication with the associated radial port and extends laterally outward from the body. A shaft extends along the inner bore, the shaft having a helical flight having at least one turn around the shaft, the flight and a bottom portion of the inner bore defining a ball receiving space large enough to receive a ball to be launched. A drive source rotates the shaft in a first direction to cause the flight to advance one or more balls toward the radial port.

Abstract: A pig receiver and method retrieve pigs in pipeline pigging operations. In one embodiment, a pig receiver includes a pig receiver unit. The pig receiver also includes a pig gate valve assembly disposed on the pig receiving unit. The pig gate valve assembly includes a gate valve. The pig gate valve assembly also includes a first actuator and a second actuator. The pig gate valve assembly further includes a cylinder guide. In addition, the pig gate valve assembly includes a tie bar. Actuation of the tie bar actuates the gate valve. An end of the tie bar is attached to the first actuator, and an opposing end of the tie bar is attached to the second actuator. The pig receiver also includes a system for removing contaminants from the pig receiver.

Abstract: Method for cleaning the conveying pipe of a pneumatic material conveying system, such as of a waste conveying system, and/or for conveying material that is in the piping, in which method at least one cleaning member is fed into a conveying pipe, and a pressure difference is achieved in the pipe and under the influence of the pressure difference the cleaning member is brought to move for cleaning the pipe, and/or for conveying material, in the conveying pipe section intended to be cleaned. In the method a cleaning member or a combination of a number of cleaning members is moved in the conveying piping, and that the cleaning member or combination of a number of cleaning members is connected to a transmission member, with which the movement of the cleaning member or combination of a number of cleaning members in the conveying piping is limited or guided. The object of the invention is also a cleaning apparatus and a system.

Abstract: A pig launching system comprising a pipe loop comprising a first end and a second end; a pig shuttle connected to the first end and the second end; a first opening in the pig shuttle aligned with the first end of the pipe loop; a second opening in the pig shuttle aligned with the second end of the pipe loop; and a slot within the pig shuttle movable between the first opening and the second opening.

Abstract: An apparatus for receiving a pig (12) comprising: a receiver housing (2) arranged to enable connection to a pipeline; a pig retention mechanism (4) mounted within said receiver housing (2), said pig retention mechanism (4) arranged such that it is operable to retain the pig (12) within the housing (2); a first sealing member (6) operable to seal the portion of the receiver housing (2) through which the pig (12) can be removed from the apparatus; a second sealing member (5) operable to seal the portion of the housing (2) that connects said receiver (1) to the pipeline; a fluid inlet (7); and a fluidization and transportation device (8) arranged to receive the fluidized debris, wherein the apparatus is arranged such that, in use, pressurized fluid is introduced into the enclosed interior of the housing (2) via the fluid inlet in order to fluidize debris which is then removed from the receiver housing (2) via the fluidization and transportation device (8).

Abstract: This invention relates to a device for cleaning a grating disc used for cutting food. The grating disc has two sets of parallel blades, the blades delineating quadrilateral-sectioned spaces in a main plane of the grating disc, a main plane of each blade being substantially perpendicular to the main plane of the grating disc. The device has at least one tooth, the tooth being sized such that it is able to be inserted into the spaces delineated by the blades. The device including a pin aligned with the tooth or teeth, an end of the pin protruding relative to one end of the tooth or teeth. The pin being capable of sliding into a space delineated by the blades at the same time that the tooth or teeth are inserted into one or more spaces delineated by the blades. This invention also relates to a set for cleaning a grating disc, comprising such a device. Finally, this invention relates to a method for cleaning a grating disc used for cutting food.

Abstract: Tapping device for beverage, including at least one beverage container, a tapping line and a tapping cock, wherein the tapping line extends at least to adjacent the tapping cock and a connector for connection of the tapping line to the at least one beverage container, wherein a cleaning element is provided in the beverage container or the connector, which cleaning element upon broaching of a beverage container is situated near an end of the tapping line proximal to the beverage container and is movable through the tapping line under pressure of beverage from the beverage container, while abutting against an inner side of the tapping line, such that beverage will propel the cleaning element in the tapping line, at least to near the tapping cock.

Abstract: An injector spool supports a plurality of ball injector assemblies having respective ball cartridges adapted to load one frac ball at a time into a ball chamber of a ball launcher of the respective ball injector assemblies to provide a horizontal frac ball injector adapted to be connected to a frac head by frac iron.

Abstract: An injector spool supports a plurality of ball injector assemblies having respective ball cartridges adapted to load one frac ball at a time into a ball chamber of a ball launcher of the respective ball injector assemblies to provide a low profile, high capacity ball injector.

Abstract: The remote controlled chemical pigging apparatus includes a housing and an inflatable device. The inflatable device contains chemicals to dissolve hardened or fossilized materials or contaminants contained within the interior portion of a pipeline, such as an oil or gas pipeline. At a specific location in the pipeline, such as at a pig apparatus receiver portion of the pipeline, the inflatable device is inflated and exploded to disperse the pipeline chemicals contained therein onto the hardened materials or contaminants that have fossilized within the pipeline. The hardened, fossilized materials or contaminants are then dissolved to liquefy the contaminants and, subsequently, to discharge the liquefied contaminants through a drain located in the pipeline. A method of cleaning a pipeline with a remote controlled chemical pigging apparatus having an inflatable device is also provided.

Abstract: A controlled aperture ball drop includes a ball cartridge that is mounted to a frac head or a high pressure fluid conduit. The ball cartridge houses a ball rail having a bottom end that forms an aperture with an inner periphery of the ball cartridge through which frac balls of a frac ball stack supported by the ball rail are sequentially dropped from the frac ball stack as a size of the aperture is increased by an aperture controller operatively connected to the ball rail.

Abstract: The present invention relates to coating of tubes, and more particularly to a system and method for coating and/or renovating deteriorated or pitted tubes to extend tube life and enhance performance. Using this system and method a thin coating is applied to the interior of a tube such that the coating is uniform in thickness and covers all regions of the tube. The coating material may be selected to minimize changes in heat transfer or may be selected to provide for the change in working fluid within the tube such that the working fluid does not negatively interact with the tube material.

Abstract: A pig receiver and method retrieve pigs in pipeline pigging operations. In one embodiment, a pig receiver includes a pig receiver unit. The pig receiver also includes a pig gate valve assembly disposed on the pig receiving unit. The pig gate valve assembly includes a gate valve. The pig gate valve assembly also includes a first actuator and a second actuator. The pig gate valve assembly further includes a cylinder guide. In addition, the pig gate valve assembly includes a tie bar. Actuation of the tie bar actuates the gate valve. An end of the tie bar is attached to the first actuator, and an opposing end of the tie bar is attached to the second actuator. The pig receiver also includes a system for removing contaminants from the pig receiver.

Abstract: Disclosed is a pig assembly for maintaining a functional line for conveying fluid. In one aspect, the pig assembly includes a larger diameter pig having an internal compartment and at least one smaller diameter pig adapted to fit therein. The larger diameter pig is capable of passing through a larger diameter functional line and the smaller diameter pig is capable of passing through a smaller diameter functional line. In another aspect, a method for maintaining a functional line for conveying fluid is provided which includes pigging a subsea line having at least a larger diameter functional line and a smaller diameter functional line in fluid communication with one another using a pig assembly as described herein.