CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional Patent Application No. 63/330,091 filed April 12, 2022, which is incorporated by reference herein to the extent that there is no inconsistency with the present disclosure.

TECHNICAL FIELD

This invention relates in general to hydrocarbon well stimulation equipment for downhole fracturing and, in particular, to a system for launching an activation device to a frac tree, to a frac tree including the system, and to method of remotely launching an activation device into a frac tree.

BACKGROUND

Current methods for completing hydrocarbon wells often involve isolating zones of interest using packers, cement and the like, and pumping fracturing fluids into the wellbore to stimulate one or more production zones of a well. For example, the casing of a cased wellbore may be perforated to allow oil and/or gas to enter the wellbore and fracturing fluid may be pumped into the wellbore through the perforations into the formation. For open, un-cased wellbores, stimulation may be carried out directly in prescribed zones without the need to perforate the production casing. The downhole completion equipment may use downhole tools that are actuated by an actuation device such as balls or darts. The downhole devices may include ball-actuated sleeves or dart-actuated sleeves, which may be arranged in series. For actuation, the frac sleeves have side ports that block fluid access to a production zone with which it is associated until an appropriate activation device is pumped down from the surface to open the sleeve. The activation device lands on a seat in the frac sleeve and frac fluid pressure on the activation device forces the side ports in the frac sleeve to open and provide fluid access to that production zone. Other types of fracing operations, and other ball- or dart-actuated downhole devices are well known in the art. This process of hydraulic fracturing ("fracing") creates hydraulic fractures in rocks, with a goal to increase the output of a well. The hydraulic fracture is formed by pumping a fracturing fluid into the wellbore at a rate sufficient to increase the pressure downhole to a value in excess of the fracture gradient of the formation rock. The fracture fluid can be any number of fluids, ranging from water to gels, foams, nitrogen, carbon dioxide, or air in some cases. The pressure causes the formation to crack, allowing the fracturing fluid to enter and extend the crack further into the formation. To maintain the fractures open after injection stops, propping agents are introduced into the fracturing fluid and pumped into the fractures to extend the breaks and pack them with proppants, or small spheres generally composed of quartz sand grains, ceramic spheres, or aluminum oxide pellets. The propped hydraulic fracture provides a high permeability conduit through which the formation fluids can flow to the well.

At the surface, hydraulic fracturing equipment for oil and natural gas fields usually includes frac tanks holding fracturing fluids and which are coupled through supply lines to a slurry blender, one or more high-pressure fracturing pumps to pump the fracturing fluid to the frac head of the well, and a monitoring unit. Fracturing equipment operates over a range of high pressures and injection rates. Many frac pumps are typically used at any given time to maintain the very high, required flow rates into the frac head and into the well.

An industry standard prior art fracturing tree ("frac tree") is typically mounted vertically above a wellhead and includes a frac head, sometimes termed a "pump block", which is a large block of steel for injecting frac fluids for pumping through the wellhead and downhole. Since the frac head is mounted above the wellhead, it may be at an elevation of about 14-16 feet (about 5 meters) from the ground. The frac head includes multiple fluid inlets which are connected to supply lines to allow frac fluids to be combined from multiple supply lines into the central bore of the frac head. The combined flow of frac fluids is pumped under pressure downwardly through a bottom outlet of the frac tree into the central bore of the wellhead. Generally, the frac tree includes one or more master valves below the frac head, and above the bottom outlet. A main axial passageway extends through the frac tree from the central bore of the frac head through the master valves to the bottom outlet. The axial passageway is generally a radial bore to accommodate radial balls or cylindrical darts being launched through the frac tree. A flow back tee, is typically a standard component of a frac tree. The flow back tee accommodates fluids flowing back through the frac tree for diversion through the one or more valved side arms. For instance, a ball catch device may be connected to one of the side arms for balls being returned from the wellbore through the wellhead.

To stimulate multiple zones in a single stimulation treatment, a series of packers in a packer arrangement is inserted into the wellbore, each of the packers being located at intervals for isolating one zone from an adjacent zone. An activation device is introduced from the frac tree into the wellbore to selectively engage one of the packers in order to block fluid flow therethrough, permitting creation of an isolated zone uphole from the packer for subsequent treatment or stimulation. Once the isolated zone has been stimulated, a subsequent activation device is dropped to engage a subsequent packer, above of the previously engaged packer, for isolation and stimulation thereabove. The process is continued until all the desired zones have been stimulated. In the case of frac balls, the balls range in diameter from a smallest ball, suitable to engage the most distant packer, to the largest diameter, suitable for engaging the packer located most proximate the surface. Other stimulating methods are known which involve dropping repeater balls of same or similar size.

U.S. Patent No. 8,636,055 issued Jan. 28, 2014 to Young et al., describes a ball drop system in which the balls are arranged vertically, on above another, with the smallest at the bottom and the largest at the top of a ball cartridge that is mounted above the frac head. 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 balls of a ball stack supported by the ball rail are sequentially dropped from the ball stack as a size of the aperture is increased by an aperture controller operatively connected to the ball rail. Depending on the number of balls needed for a system, this system adds excessive height to the overall frac tree, raising safety issues and making it difficult and costly to service and install. As well, when exposed to the high pressures of the frac tree system, and coupled with the extreme freezing temperatures during use, the balls may fail to release when the aperture is opened. When operational problems occur, such as malfunctioning valves or activation devices becoming stuck and not being pumped downhole, these problems may result in failed well treatment operations, requiring costly and inefficient re-working. At times re-working or re-stimulating of a well formation following an unsuccessful stimulation treatment may not be successful, resulting in a production loss.

Another technique to introduce frac balls involves an array of remote valves positioned onto a multi-port connection at the wellhead with a single ball positioned behind each valve. Each valve requires a separate manifold fluid pumper line and precise coordination both to ensure the ball is deployed and to ensure each ball is deployed at the right time in the sequence, throughout the stimulation operation. The multi-port arrangement requires multiple high pressure valves and other equipment, increasing the capital costs for the frac operation. The multiplicity of high pressure lines also logistically limits the number of balls that can be dropped due to wellhead design and available ports without re-loading. U.S. Patent No. 9,109,422 to Ferguson et al. discloses a system of this nature. The balls are individually pumped directly into the frac head where high turbulence may damage the balls. As well, larger packer balls generally need to be launched from above the frac tree, making the launch more complicated.

Applicant's previously patented ball drop system is described in U.S. Patent Nos. 8,256,514 and 8,561 ,684 to Winzer. The ball drop system includes a vertically stacked manifold of pre-loaded balls oriented in a vertical stack in a bore which is axially aligned above the main axial passageway of the frac head. Each ball is temporarily supported in the bore by a rod. Each rod is sequentially actuated to withdraw from the bore when required to release or launch the next largest ball. The lowest ball (closest to the wellbore of the wellhead) is typically the smallest ball, although same sized balls may be loaded.

U.S. Patent No. 10,435,978 to Corbeil describes a ball drop system mounted above a wellhead assembly. The balls are loaded in a vertical stack in an manifold, with each ball temporarily supported on a hinged pin for sequential dropping into the bore of the wellhead assembly. The wellhead assembly includes ball launch valves above and below a staging assembly to allow the balls to be sequentially dropped into the wellhead located therebelow, while maintaining the ball injector at atmospheric pressure.

Applicant’s previously patented ball injector system and method are described in U.S. Patent Nos. 10,161 ,218 and 10,731 ,436 to Allen et al. The ball injector is connected below the frac head of the frac tree to sequentially inject frac balls from a ball cartridge into the main axial passageway of the frac tree. Valve members in a ball launch passageway enable the ball to be passed from atmospheric conditions in the ball cartridge to high pressure conditions in the main axial passageway of the frac tree.

In most of the above launch systems, if an activation device is damaged or disintegrates upon arrival at the downhole tool, a replacement must be reloaded and launched again. If the launch system is pressurized, as it is for most of the prior art systems, the entire apparatus must be depressurized, removed and reloaded for the replacement activation device. Due to the size, weight and height of these systems, this is a time consuming and costly process, and must be carefully managed to maintain safe control in a hazardous environment and to complete testing and re-pressurization procedures upon reinstallation to the wellhead. An atmospheric launch system addresses some of these issues.

To address prior art problems, it has recently become possible to use cylindrical darts instead of a series of sized frac balls to engage and/or activate downhole tools. The cylindrical darts may carry mechanical activation devices to activate the downhole tool, or they may carry sensors to activate the downhole tool. The latter type of cylindrical frac darts are often termed “smart darts”. The use of darts in the fracing industry changes the requirements for the launching systems and methods at the surface. This disclosure is directed to improvements in the launching of activation devices such as balls, darts and plugs to activate downhole tools.

It is also important to note that the fracturing operations involve a large number of trucks, pumps, containers, hoses or other conduits, and other eq uipment for a fracturing system. In practice, many trucks and pumps are used to provide the cumulative amounts of fluid for the well at a well site which are moved from well to well. The difficulty of working around the wells with the large number of components also causes safety issues. The number of assembled equipment components raises the complexity of the system and the ability to operate in and around the multiple wells. An area within about 20-30 m of the well is termed a “hot zone”, and access to the hot zone is restricted for safety reasons. Improvements are still needed in the launching of activation devices to simplify the complexity and reliability of the system and to improve overall safety of the fracturing operation.

SUMMARY

This disclosure provides a system for launching an activation device to a frac tree. The system includes: a loading station for the activation device, the loading station being located remotely from the frac tree; a staging valve system adapted to connect to the frac tree for staging the activation device from a low pressure zone above the staging valve system to a high pressure zone in the frac tree; a pneumatic line connected to the loading station for delivering the activation device to the staging valve system; an air source to impart air pressure within the pneumatic line to pneumatically convey the activation device through the pneumatic line from the loading station to the staging valve system.

In some embodiments, the pneumatic line is tubular, and the system further includes a carrier for pneumatically conveying the activation device in the pneumatic line. In some embodiments the carrier has a generally cylindrical body, at least one closed end, and one or more circumferential seals carried on an outer surface of the carrier to support the carrier within the pneumatic line and to pneumatically convey the carrier through the pneumatic line when air pressure from the air source is imparted on the closed end of the carrier.

In some embodiments, the system further includes a launch housing connected above the staging valve system, the launch housing having a housing inlet and a housing outlet and a launch passageway extending between the housing inlet and the housing outlet, the launch passageway being shaped and sized to accommodate the activation device for delivery from the housing inlet to the housing outlet, the housing outlet being axially aligned with, and connected to, the staging valve system. The pneumatic line is connected to the housing inlet of the launch housing such that the activation device is pneumatically conveyed through the pneumatic line from the loading station for discharge from the carrier to the housing inlet for delivery via the launch passageway and the housing outlet to the staging valve system.

In some embodiments, the system includes a vented adaptor located in the pneumatic line between the loading station and the staging valve system for discharging the activation device from the carrier for delivery to the staging valve system.

In some embodiments the system includes a stop at the housing inlet or at the vented adaptor to stop the carrier and for discharging the activation device from the carrier. In some embodiments the system includes an air source to impart vacuum pressure to return the carrier to the loading station. In some embodiments the pneumatic line of the system includes flexible hose in one or more sections, combinations of joined pipe sections and/or joined flexible hose sections, or combinations of curved pipe sections and linear pipe or hose sections. In some embodiments the system provides for venting in the launch housing or the vented adaptor. In some embodiments the system provides an angular orientation of the launch passageway. In some embodiments the system includes one or more position indicators, sensors and/or cameras for monitoring progression of the activation device.

In some embodiments, the staging valve system includes a first valve member, a second valve member adapted to connect to the frac tree, and a pressure isolation passageway between the first and second valve members, wherein the first and second valve members and the pressure isolation passageway are axially aligned one with another and with an axial passageway of the frac tree, and permit passage of the activation device from the pneumatic line through the staging valve system to the frac tree. In some embodiments the staging valve system further comprises a wing valve connecting to the pressure isolation passageway for introducing fluid under pressure to the pressure isolation passageway for launching the activation device through the staging valve system, and for releasing pressure from the staging valve system. In some embodiments, the staging valve system includes a valved pressure equalizing line fluidly connecting a frac head of the frac tree to the pressure isolation passageway for using frac stream pressure to pressurize the pressure isolation passageway for launching the activation device through the staging valve system. A bleed off valve may be included connecting the pressure isolation passageway for releasing pressure from the staging valve system.

This disclosure also provides a frac tree including the above-described system connected into the frac tree

This disclosure also provides a method of remotely launching an activation device into a frac tree. In some embodiments, the method includes: a) providing a loading station for the activation device located remotely from the frac tree; b) providing a staging valve system adapted to connect to the frac tree for staging the activation device from a low pressure zone above the staging valve system to a high pressure zone in the frac tree; c) providing a pneumatic line connected to the loading station for delivering the activation device to the staging valve system; d) loading an activation device at the loading station into the pneumatic line; and e) pneumatically conveying the activation device through the pneumatic line from the loading station to the staging valve system.

In some embodiments, the method further includes pneumatically conveying the activation device through the pneumatic line with a carrier pneumatically sealed in the pneumatic line.

In some embodiments the method further includes: providing a launch housing for connecting to the staging valve system, the launch housing having a launch passageway extending from a housing inlet to a housing outlet, and the launch passageway being shaped and sized to accommodate the activation device for delivery from the housing inlet to the housing outlet; providing the pneumatic line between the loading station and the housing inlet; and pneumatically conveying the activation device with the carrier through the pneumatic line and discharging the activation device from the carrier to the housing inlet of the launch housing, such that the activation device is delivered via the launch passageway and the housing outlet to the staging valve system.

In some embodiments the method further includes: providing a vented adaptor in the pneumatic line between the loading station and the staging valve system for discharging the activation device from the carrier for delivery to the staging valve system; providing the pneumatic line between the loading station and the staging valve system; and pneumatically conveying the activation device with the carrier through the pneumatic line to the vented adaptor and discharging the activation device from the carrier for delivery of the activation device to the staging valve system.

BRIEF DESCRIPTION ON THE DRAWINGS

FIG. 1 is a schematic, side perspective view of one embodiment of this disclosure of a system for launching an activation device from a ground level loading station with an air source, both of which are located remotely from a frac tree, i.e., outside the hot zone, to a launch housing connected above the frac tree, with a pneumatic line extending between the loading station and the launch housing, and with the launch housing being connected to a staging valve system, which is in turn connected to the frac tree.

FIG. 2 is a partially cut-away view of the details of circle A of FIG. 1 , showing a carrier and a cylindrical dart being pneumatically conveyed in the pneumatic line.

FIG. 3 is a side view, partially in section, showing the launch housing connected to the staging valve system to move the actuation device from a low pressure zone of the launch housing to a high pressure zone of the frac tree.

FIG. 4A is sectional view of the cylindrical carrier of FIG. 2, showing a closed end, an open end and spaced circumferential seals for pneumatic conveying a cylindrical activation device in the cylindrical body of the carrier.

FIG. 4B is a sectional view of another embodiment of a cylindrical carrier, showing both ends closed and spaced circumferential seals for pneumatic conveying an activation device which is pushed ahead of the carrier.

FIGS. 5A-5C are schematic views of the loading station of FIG. 1 , with FIG. 5A being a sectional view to show the carrier and dart loaded through the loading port door, FIG. 5B being a top view showing the loading port door in a closed position, and FIG. 5C being a side view showing the closed position of the loading port door.

FIG. 6 is a sectional view of the launch housing showing the progression of a single cylindrical activation device moving from a stowed position (position a) in the carrier and as it is gravity fed from the housing inlet into and through the launch passageway (position b), to the housing outlet for hands free delivery to the housing outlet (position c).

FIG. 7 is a schematic, top view of the air source connected to the loading station, with controls to switch from imparting air pressure into the pneumatic line for pneumatic conveyance, to imparting vacuum pressure to the pneumatic line for returning the carrier from the launch housing to the loading station.

FIG. 8 is a schematic, side perspective view of an alternate embodiment of this disclosure of a system for launching an activation device from a ground level loading station and air source located remotely from a frac tree, with a pneumatic line extending between the loading station and a staging valve system, which is in turn connected to the frac tree. The pneumatic line is shown to include spiral wound flex hose for linear sections and curved aluminum pipe for curved sections. The pneumatic line includes a vented adaptor between the loading station and the staging valve system to discharge the activation device from the carrier for delivery to the staging valve system.

FIG. 9 is a side sectional view of the connection of the vented adaptor of FIG. 8 in the pneumatic line.

FIG. 10 is a side view of the staging valve system of FIG. 8 showing a valved pressure equalizing line to use frac stream pressure to launch the activation device through the staging valve system and to equalize the pressure in the staging valve system after the launch.

FIG. 11 is a side perspective view of the air source and loading station of FIG. 8, showing valve controlled bleed off and inlet ports for the air source. FIG. 12 is a top view of the air source and the loading station of FIG. 8.

FIGS. 13A and 13B are top views of the loading station of FIG. 8, with FIG. 13B being partially cut away to show the carrier within the loading station.

FIGS. 14A and 14B are sectional views of the alternate embodiments of the carrier.

DETAILED DESCRIPTION

TERMS AND DEFINITIONS

Certain terms or phrases used herein and in the claims have meanings as set out hereinbelow.

Although described in the embodiments as having a cylindrical configuration, the term “activation device” is used throughout this disclosure and in the claims to be generic to other configurations of activation devices configured to engage and/or activate a downhole tool, for example by shifting a sliding sleeve as described above. The term “activation device” specifically includes spherical and cylindrical configurations, for example, darts, balls, plugs, semi-ellipsoidal configurations, and other configurations capable to sealing or restricting fluids by engaging a seat, or otherwise activating, an activation or de-activation mechanism in a downhole tool.

“Axial” and “longitudinal” are used to indicate a direction or center axis along a line substantially parallel with, or along, a lengthwise direction, for example of a axial passageway through a launch housing, a staging valve system, a frac head or a frac tree, or other feature at the relevant point or portion of the feature under discussion.

“Radial” means a direction or including a directional component substantially along a line that intersects the center axis of the feature under discussion, for example which lies in a plane perpendicular to the center axis.

“Circumferential” means a substantially arcuate or circular path described by rotation of a tangential vector about a center axis of the feature under discussion, for example along the outer surface of a cylindrical carrier or activation device.

As used herein, movement or location “forwards” or “downhole” (and related terms) means axial movement or relative axial location towards a frac head, frac tree, wellhead or downhole tool, away from the earth's surface. Conversely, “rearwards,” means movement or relative location axially away from the downhole, including upwardly though the wellhead, frac tree, frac head, staging valve system, launch housing and returning to the earth’s surface.

“Above” or “below” as used herein denote a location generally vertically above or below another feature under discussion, for example a frac head or a frac tree, without implying a strictly vertical position, for example including a vertically raised position relative to another feature, and without excluding other intervening connected features such as valves, adaptors etc.

“Connected”, “connecting” and “connection” are used herein to include direct and indirect connections between features under discussion, without excluding other intervening connected features such as valve, adaptors or other components. Connections between wellhead, frac tree and staging valve system components are understood to be pressure connections with seals to withstand industry standard pressure ratings.

Exemplary embodiments of a launch system and method of launching for an activation device and its components are shown in FIGS. 1-14, and are described in detail hereinbelow.

FIG. 1 shows an exemplary embodiment of a launch system for launching an activation device to a frac tree. One embodiment of an activation device is shown in FIG. 2 as a cylindrical dart 41. The launch system 40 is shown connected to one exemplary embodiment of an industry standard fracturing tree ("frac tree") 10. The components of the frac tree 10 include a bottom connector 12 for mounting to a wellhead (not shown but located below the frac tree). The frac tree 10 includes a frac head 20, sometimes referred to in the industry as a "pump block", which is a large block of steel for injecting frac fluids into the frac tree 10 under high pressure. As used herein and in the claims, the term "frac head" is understood to comprise the block of a frac tree 10 into which frac fluids are pumped under pressure through side inlets 28, or through other blocks, valves and inlets connected thereto. The frac head component 20 of the frac tree 10 is mounted above the wellhead, so may extend generally vertically upwardly to an elevation of about 14-16 feet (about 5 meters) from the generally horizontal ground at the earth’s surface. The connections between components of the frac tree 10 are shown as studded up/studded down connections or flange connections, however, other known connections may be used. Supply lines (not shown) are attached to the side inlets 28. The side inlets 28 allow the frac fluids to be pumped under pressure through one or more valves (not shown) from multiple supply lines into the central bore of the frac head 20. The combined flow of frac fluids is pumped downwardly under pressure into the central bore of the wellhead. In FIG. 1 , the frac tree 10 includes one or more master valves and/or swab valves 30 below the frac head 20. The valves 30 are generally industry standard gate valves which may be manually controlled or remotely controlled such as hydraulically. An axial passageway 32 extends through the frac tree 10 from the central bore (not shown) of the frac head 20 through the master valves 30. The axial passageway 32 is generally a radial passageway. FIG. 1 also shows a flow back tee 34, which is usually also a standard component of a frac tree 10. The flow back tee 34 accommodates fluids flowing back through the frac tree for diversion through the one or more valved side arms 36. The axial passageway 32 of the frac tree 10 also extends through the flow back tee 34, if present. Other components, such as valves or adaptors may be present in a frac tree 10, as is well known in the industry.

The launch system 40 of FIG. 1 is shown connected to a staging valve system 42 connected to the frac head 20 of the frac tree 10. The connections between components of the staging valve system 42, the frac head 20 and the frac tree 10 are shown to be industry standard flange connections or studded up/studded down connections, with pressure rated seals. However, other industry standard connections with seals rated for the high pressure within the frac tree 10 may be used, for example welded, threaded or hub connections.

The launch system 40 includes a loading station 44 and an air source 46, both of which are located remotely from the frac tree 10, i.e., outside the hot zone of a well pad on which the frac tree 10 is located. This hot zone distance may, for example, be about 20-30 m from the frac tree 10.

In some embodiments, the launch system 40 further includes a launch housing 48 located above the frac tree 10, connected to the staging valve system 42. The launch housing 48 includes a housing inlet 50, a housing outlet 52 and a launch passageway 54 extending between the housing inlet 50 and the housing outlet 52 (see FIGS. 3, 6). A pneumatic line 56 is connected to, and extends between, the loading station 44 and the housing inlet 50 of the launch housing 48. The connection of the pneumatic line 56 to the loading station 44 is shown as a flange connection 58, while the connection to the housing inlet 52 is shown as a reinforced threaded connection 60 (see FIG. 6). In some embodiments, the pneumatic line connections vary, for example with the type, weight, and angle of connection of the pneumatic line 56, but exemplary pneumatic line connections include industry standard flange, threaded, hose clamp, wing union, hammer union, and welded connections, or cam lock fittings.

In some embodiments, the launch housing 48 is optional, i.e. , it is not included. In embodiments without the launch housing, the pneumatic line 56 is connected to the staging valve system 42 such that the activation device 41 is discharged from the pneumatic line 56, optionally through one or more adaptors or connectors, to the staging valve system 42.

The staging valve system 42 is shown in FIG. 3 to include a first valve member 62, a pressure isolation housing 64 and a second valve member 66. A generally radial valve passageway 68 extends through the valve members 62, 66 and the pressure isolation housing 64, sized to allow the activation device 41 to pass therethrough, into the frac head 20 of the frac tree 10, when the valve members 62, 66 are in open positions. The valve passageway 68 is axially aligned with the housing outlet 52, and with the axial passageway 32 extending through the frac tree 10. The valve members 62, 66 are shown as an industry standard gate valves, but other industry standard valves may be used in other embodiments. In FIG. 3, the staging valve system 42 is shown to include a wing valve 70 connected to the pressure isolation housing 64. A pressure isolation passageway 72 extending through the pressure isolation housing 64 is shown to be generally T-shaped, with a side passageway 74 extending through the wing valve 70 for introducing fluid under pressure into the pressure isolation passageway 72. In some embodiments, the pressure isolation passageway 72 may be cross shaped, for example with the pressure isolation housing comprising a 4-way cross, with wing valves on both side arms.

The staging valve system 42 thus permits staging the activation device 41 from a low pressure zone within the pneumatic line 56, and at the housing outlet 52 of the launch housing 48 if present, to a high pressure zone in the frac tree 10 through the first and second valve members 62, 66 and the pressure isolation housing 64. In embodiments without the launch housing, the pneumatic line 56 may be connected, directly or indirectly through one or more adaptors or connectors, to the first valve member 62, with the pneumatic line 56 being axially aligned with the valve passageway 68 at this connection.

Before launching the activation device 41 , the valve members 62, 66 and 70 are in the closed position. Wing valve 70 is opened to confirm atmospheric pressure in the pressure isolation passageway 72. The first valve member 62 is opened from an initially closed position to allow the activation device 41 to be launched. The activation device 41 is pneumatically conveyed and is delivered to and through the launch housing 48, or to the first valve member 62 in embodiments without the launch housing 48. The activation device 41 drops through the first valve member 62 to a void space (i.e. initially empty or filled with residual fluid to cushion the activation device 41) in the pressure isolation passageway 72 between the valve members 62, 66. The first valve member 62 is then closed. With the second valve member 66 in an initially closed position, fluid pressure may be introduced, for example through wing valve 70, to pressurize the pressure isolation passageway 72 to a pressure equal to or exceeding the fluid pressure of the axial passageway 32 of the frac tree 10 (i.e., the frac stream pressure). The second valve member 66 is opened to allow the activation device 41 to be launched from the pressure isolation passageway 72 to the axial passageway 32 of the frac tree 10. The wing valve 70, and then the second valve member 66, are closed, and fracing operations continue, with the activation device 41 being pumped down through the frac head 20. The pressure within the staging valve system 42 and progression of the activation device 41 may be monitored with one or more sensors, for example a pressure sensor within the pressure isolation passageway 72, and one or more position indicators/sensors located with access along the valve passageway 68. For the next cycle of launching a subsequent activation device 41 , the pressure in the pressure isolation passageway 72 is released, for example by opening the wing valve 70.

In some embodiments, pressurizing the pressure isolation passageway 72 includes opening the initially closed wing valve 70 into the pressure isolation passageway 72, and pumping fluid into the passageway 72 to provide a fluid pressure above the fluid pressure of the axial passageway 32 of the frac tree 10. This is followed by either a) closing the wing valve 70 before opening the second valve member 66, or b) leaving the wing valve 70 open and continuing to pump fluid into the isolation passageway 72 after the second valve member 66 is opened to assist in launching the activation device into the axial passageway 32 of the frac tree.

In some embodiments, the staging valve assembly 42 includes a pressure relief chamber connected to a pressure pump (not shown) to relieve pressure below the launch housing 48 before opening the first valve member 62.

The launch passageway 54 of the launch housing 48 is shaped and sized to accommodate the activation device 41 for gravity delivery from the housing inlet 50 to the housing outlet 52. In some embodiments, as shown in FIGS. 2, 4, 5 and 6, the activation device 41 is generally cylindrical with a forward end 41a, being the end with first enters the housing inlet 50, and an opposing rearward end 41b, and with a length dimension being the distance between the ends 41a, 41b. The launch passageway 54 is shown in FIG. 6 to be generally radial with one or more radial dimensions (i.e., each diameter though the housing inlet 50, outlet 52 and through the passageway 54) being less than the length dimension of the activation device 41 . The sidewalls 54a of the launch passageway 54 are thus spaced apart to guide and direct the activation device 41 from the inlet 50 to the outlet 52, with the forward end 41a first arriving at the housing outlet 52, and such that the activation device 41 is generally axially aligned with the housing outlet 52 when it arrives at the outlet 52, without permitting significant rotational or end to end twisting movement in the launch passageway 54. This prevents an activation device 41 becoming stuck in the launch passageway 54 and enables gravity delivery, front end first, at the outlet 52. The feature of gravity delivery and progression through the launch housing 54 is shown in FIG. 6 for a single activation device 41 as it moves from a stowed position (a) in the carrier 80, as it is gravity fed from the housing inlet 50 into and through the launch passageway 54 in position (b), and as it is guided and directed downwardly at position (c) to the housing outlet 52, for hands free delivery to the housing outlet 52. In the above described embodiments, the activation device 41 is shown as a cylindrical dart, but in some embodiments, the activation device may be spherical, such as a frac ball, and the launch passageway has a radial dimension to accommodate the diameter of the frac ball.

In some embodiments, the housing inlet 50 and outlet 52 are arranged such that the center axis of the inlet 50 and the outlet 52 are axially aligned. While not shown in the figures, it will be understood that, in such embodiments, the launch passageway 54 extends generally vertically through the launch housing 48, with the inlet 50 being located at the top of the launch housing 48.

In some embodiments, the launch passageway 54 follows a smooth radial passageway in a downward arc from the housing inlet 50 to the housing outlet 52 to minimize impact of the activation device 41 within the launch passageway 54.

In some embodiments, the launch passageway 54 includes a liner such as a plastic liner, to provide a smooth radial passageway for the activation device 41 .

In some embodiments, the housing inlet 50 and outlet 52 are arranged such that the center axis of the inlet 50 and outlet 52 intersect at an angle between 90 and 180 degrees, such as between 125 and 180 degrees or between 135 and 160 degrees. Since the outlet 52 is axially aligned with the axial passageway 32 of the frac tree, this angled pathway through the launch housing 48 places the housing inlet 50 in a side wall 48a of the launch housing 48 (see FIG. 6). This angled orientation of the launch passageway 54 ensures and improves gravity delivery of the activation device 41 from the inlet 50 to the outlet 52, particularly for a cylindrical activation device 41 , while also lessening the length and curvature of the pneumatic line 56 extending between the loading station and the housing inlet 50.

In some embodiments, such as shown in FIGS. 1 , 2, 4 and 6, the pneumatic line 56 is tubular, and flexible, such as in the form of a flexible hose or piping 56a. In some embodiments, the flexible hose 56a is provided in a single length, or in multiple joined lengths (sections), and with a smooth curvature to accommodate the ground connection at the loading station 44 and raised connection to the launch housing 48 above the frac tree 10. In some embodiments, the flexible hose 56a has one or more transparent portions to provide visual monitoring of the pneumatic conveyance. In some embodiments, the flexible hose 56a is spiral wound flexible hose with a generally smooth inner wall for sealed pneumatic conveyance. In other embodiments, the pneumatic line 56 may include one or more sections of hard piping joined with flexible piping, and/or sections of aluminum reinforced piping joined with flexible piping. In some embodiments the pneumatic line may include one or more straight sections joined with one or more flexible and/or curved sections, for example spiral wound hose sections joined to curved aluminum sections. In some embodiments the flexible piping can include carbon fiber piping or corrugated piping. Exemplary materials for the flexible hose 56a include PVC, polyurethane and other flexible plastics. It should be understood that some air leakage within the pneumatic line and connections is permitted, such that pneumatic sealing need not be air tight sealing.

In some embodiments, pneumatically conveying the activation device 41 through the pneumatic line 56, to the housing inlet 50 of the launch housing 48 if present, or to the first valve member 62 of the staging valve system 42 if the launch housing is not present, includes using a carrier 80 within the pneumatic line 56 to carry the activation device 41 (FIG. 4A), or to push the activation device (FIG. 4B). The carrier 80 may be formed from a light weight material for ease of conveyance, for example from metals such as aluminum, or from hard plastics such as polycarbonate or Teflon™. The carrier 80 includes a generally cylindrical body 82 with at least one closed end 84. In some embodiments the carrier 80 is generally hollow for ease of conveyance, and for carrying the activation device 41. The carrier includes one or more seals 86 carried on an outer surface 80a of the carrier 80 to support the carrier 80 within the pneumatic line 56. The seals 86 may be one or more circumferential seals 86, for example two or more spaced circumferential seals of low friction materials with high strength and high wear, for example hard plastics such as hydrogenated nitrile (HNBR), polytetrafluoroethylene (PTFE) seals such as Teflon™, high density polyethylene (HDPE), ultra high molecular weight polyethylene UHMW polyethylene, polyacrylate rubber (ACM), highly saturated nitrile (HSN) and nitrile rubber (NBR), fibrous seals such as leather, reinforced fiber seals, or composite seals of both plastic and fibrous materials. The seals 86 and body 82 are sized for close contact with the inner wall 56b of the pneumatic line 56 such that air pressure from the air source 46 imparted on the closed end 84 of the carrier 80 pneumatically conveys the carrier 80 and the activation device 41 through the pneumatic line 56. In some embodiments, additional low friction seals or guides may extend longitudinally, for example as longitudinal plastic strips or runners, or metal blades, radially spaced around the outer surface. Exemplary low friction materials include polytetrafluoroethylene (PTFE), ultra high molecular weight polyethylene (UHMW polyethylene), and high density polyethylene (HDPE). In other embodiments, the outer surface may include other support features such as low friction spacers, bars or wheels radially spaced around the outer surface.

In the embodiment of FIG. 4A, the closed end 84 of the carrier 80 is rearward facing toward the air source 46, and the opposing end of the carrier is an open end 88, such that the activation device 41 is discharged through the open end 88 to the housing inlet 50 of the launch housing 48 in a hands free manner (i.e. , without human hands contacting the carrier or the activation device 41. This embodiment is well adapted for pneumatic conveying of a cylindrical smart dart, but may also be used for other shaped activation devices.

In the embodiment of FIG. 4B, both ends of the carrier 80b are closed ends 84b, 84c, such that the activation device 41 , whether cylindrical or of a different shape such as a spherical frac ball, is pushed ahead of the carrier 84b during pneumatic conveyance.

To assist in discharging the activation device 41 at the housing inlet 50, a stop 90 is provided or formed at the housing inlet 50 to prevent the carrier 80 from traveling through the housing inlet 50. In FIG. 6, the launch housing 48 includes a side arm portion 92 forming the housing inlet 50, for connection to the pneumatic line 56. The inside diameter of the cylindrical body 82 of the carrier 80 is less than or equal to the inside diameter of the launch passageway 54 at the housing inlet 50, such that the stop 90 is formed by the wall 94 of the side arm 92 around the housing inlet 50. In this manner, the cylindrical body 82 contacts the wall 94, preventing the carrier 80 from traveling into or through the inlet 50. This abrupt stopping of the pneumatic conveyance assists in launching the activation device 41 from the carrier 80 into the inlet 50 and the launch passageway 54, providing momentum to the activation device 41 , in addition to gravity acting on the activation device 41 , for delivery to the housing outlet 52. The side arm 92 of the launch housing 48 may be reinforced, for example metal reinforced, to support the connection to the pneumatic line 56. The side arm 92 may also form one or more air vents 96 to vent air pressure from the launch housing 48, either due to pneumatic conveyance, or due to upward pressure from the staging valve system 42 or components located therebelow.

The air source 46 shown in FIGS. 1 and 7 provides a bidirectional air supply to the pneumatic line 56. The air supply 46 is shown to be located rearwardly of the loading station 44 to provide air pressure against the carrier 80, once the carrier 80 and activation device 41 are loaded into the pneumatic line 56. The air source 46 is shown to include a regenerative air blower 46a with an air line 100 and a vacuum line 102, which are joined for connection to the loading station 44. The lines 100, 102, include controls 104, 106 to switch between imparting air pressure in the pneumatic line 56 and imparting vacuum pressure in the pneumatic line 56. Once the activation device 41 is discharged at the housing inlet 50 (or to the first valve member 62 in embodiments without the launch housing), the air line control 104 is closed, and the vacuum line control 106 is opened to return the empty carrier 80 to the loading station 44 by imparting vacuum pressure to the carrier 80 in the pneumatic line 56. To launch each subsequent activation device 41 , and to return the carrier to the loading station 44, the pneumatic conveyance and vacuum return steps are repeated.

To load the activation device 41 at the loading station 44, the loading station 44 includes a tubular loading housing 110 (see FIGS. 5A-C and 7) sized to accommodate the carrier 80 and the activation device 41. The loading housing 110 has an adapter end 112 forming a reduced diameter adapter 114 connected to the joined section 101 of air/vacuum lines 100, 102. The opposed end 116 of the loading housing 110 forms the flange connection 58 to the pneumatic line 56. A sealed loading port 120 is formed in the upper surface of the loading housing 110 for loading of the carrier 80 and the activation device 41. An arcuate loading port cover 122 provides open and closed positions of the port 120. The cover 122 may be hinged along a side or end for opening and closing, and the cover 122 may carry perimeter seals on its underside for sealing the port 120 in the closed position.

FIGS. 8-14 show alternate embodiments of a system for launching an activation device 41 in which like reference numerals from FIGS. 1-7 are generally used to denote like features which have been previously described. In FIG. 8, the launch system is shown generally as 40', the pneumatic line is shown generally as 56', the staging valve system is shown generally as 42' and the frac tree is shown as generally as 10'. The launch system 40' includes a ground level loading station 44' and an air source 46' located remotely from a frac tree 10', with the pneumatic line 56' extending between the loading station 44' to the staging valve system 42'. The pneumatic line 56' includes a vented adaptor 200 in the pneumatic line 56' between these end connections. The staging valve system 42' is connected to the frac tree 10'.

The pneumatic line 56' is shown to include two linear sections of spiral wound flex hose 202 and three curved aluminum pipe sections 204. Wing union connections 206 are shown between spiral wound flex hose sections 202 and curved aluminum sections 204, while flanged connections 207 are shown at the vented adaptor 200, between joined curved aluminum sections 204, and between the curved aluminum pipe section 204 and the top connector 209 of the staging valve system 42' (for example, the top flange 209 of valve 62). Wing union connections 206 are also shown for connections of the pneumatic line 56' to the loading station 44' and to the vented adaptor 200.

In FIG. 8, the two joined curved aluminum pipe sections 204 are shown to extend above the height of the staging valve system 42', forming a raised section R of the pneumatic line 56', with an arc of curvature to accommodate the dimensions of the activation device 41. The vented adaptor 200 is located in the pneumatic line 56', generally in this raised section R of the pneumatic line 56' such that the activation device 41 can be discharged from the carrier 80 upon striking a stop 90' located in the vented adaptor 200 (see FIG. 9). The stop 90' thus has a similar discharge function to stop 90 shown in FIG. 6. The discharged activation device 41 has momentum to continue travel through the remaining length of the pneumatic line 56' for gravity delivery with a generally vertical orientation into the staging valve system 42'. The vented adaptor thus provides the function of the launch housing of FIG. 1 , and the launch housing is omitted from the embodiment of FIG. 8. The passageway 208 through the vented adaptor 200 is shaped and sized to accommodate a carrier 80 and the activation device 41. The vented adaptor 200 includes vents 200a for air flow and to release any fluid from the pneumatic line 56'.

The staging valve system 42', as shown in FIGS. 8 and 10, includes the valves 62, 66, the pressure isolation housing 64, and the pressure isolation chamber 72, each of which is generally as described for FIG. 3. A bleed off valve 70' replaces wing valve 70 from FIG. 3, and is connected to the pressure isolation housing 64 for fluid connection to the pressure isolation passageway 72. To use frac stream pressure for launching of an activation device 41 through the staging valve system 42', and to allow for pressure equalizing after launch, the staging valve system 42' includes a pressure equalizing line 210 fluidly connected between the frac head (or pump block) 20 and the pressure isolation passageway 72 of the pressure isolation housing 64. The pressure equalizing line 210 connects through a frac inlet block 212 to the frac head 20, and includes an equalizing flow tee 214 connected to the pressure isolation housing 64, and a pressure equalizing valve 216 connected between the block 212 and the tee 214. Before launching the activation device 41 through the staging valve system 42', valves 62, 66, 70' and 216 are in the initially closed position. Bleed off valve 70' is opened to confirm atmospheric pressure in the pressure isolation passageway 72 of the pressure isolation housing 64 (the pressure isolation housing 64 and passageway 72 are as shown in FIG. 3). Bleed off valve 70' is closed, and valve 62 is opened to allow the activation device 41 to be launched and to drop into the pressure isolation passageway 72. Valve 62 is closed and pressure equalizing valve 216 is opened to use frac stream pressure, applied at frac inlet 213 to the frac inlet block 212, to pressurize the pressure isolation passageway 72. Valve 66 is opened to allow the activation device 41 to pass through valve 66 into the frac head 20. The pressure equalizing valve 216 is closed, then valve 66 is closed, and the pressure is released from the pressure equalizing line 210, for example through bleed off valve 70'. The staging valve system 42' is returned to the initial valves closed position, ready for launching of a subsequent activation device 41.

The air source 46' and the loading station 44' of FIG. 8 are shown in greater detail in FIGS. 11 , 12, 13A and 13B. The air source 46' is similar to that described for FIGS. 1 and 7, but includes a valve controlled bleed off port 220 and valve controlled inlet port 222 as part of the controls for the air source 46'. The loading station 44' is similar to that described for FIG. 1 , but is adapted for a wing union connection 206 to the pneumatic line 56'.

Alternate embodiment of the carrier 80' are shown in FIGS. 13B and 14B.

The carrier 80' is formed from a light weight material such as aluminum, polycarbonate or Teflon™, the open front end 88 of the carrier body 82 is tapered, and the closed end 84 is formed by an end plate 84a bolted to the carrier body 82. In FIG. 13B, the circumferential seals 86' are spaced apart on the outer surface 80a of the carrier 80'. In FIG. 14B, the circumferential seal 86" of the carrier 80' is an air block seal formed for example from a reinforced fibrous material.

A further alternate embodiment of a carrier 80" is shown in FIG. 14A. The cylindrical body 82 is formed from a light weight material such as aluminum, polycarbonate, or Teflon, and is thin walled with tapering at both the closed end 84 and at the open end 88. Spaced apart circumferential seals 86' are provided on the outer surface 80a of the carrier 80", formed from a fibrous seal material such as leather.

While the loading station 44 (and 44') is shown schematically as being ground supported, it will be understood that in some embodiments the loading station may be elevated to decrease the rise or height of raised section R of the pneumatic line 56 (and 56') and thus the work to convey the carrier 80 (and 80', 80") and the activation device 41 from the loading station 44 into the frac tree 10 (and 10'). In some embodiments the loading station 44 may be adapted to accept a magazine loaded with a plurality of activation devices for sequential loading into the carrier 80. In some embodiments, the loading station 44 may be adapted to open the door 122 of the loading station 44 on return of the carrier 80 to the loading station 44. In some embodiments, the loading station 44 and the air source 46 (and 46') may be located within a climate controlled environment, for example in a trailer equipped for human and/or computer operations and monitoring. In some embodiments the air source 46 may be located elsewhere than rearwardly of the loading station 44, for example proximate the launch housing 48, if present, or the staging valve assembly 42. The air source 46 may be adapted to use blowing air for the conveying path, i.e., to convey the carrier 80 and activation device 41 along the pneumatic line 56 for launching into the frac tree 10, and then vacuum for the return path, or the air source 46 may be adapted to use vacuum for the conveying path and blowing air for the return path.

Monitoring can be achieved remotely, by including one or more position indicators, sensors, and/or cameras at, within, or between the loading station 44 and the staging valve system 42. In some embodiments, the activation device 41 may carry passive triggering features for monitoring by external sensors. For example one or more Hall-Effect sensors may be provided at the launch housing 48 with access to the launch passageway 54 to monitor successful launch at the inlet 50 and gravity feed to the outlet 52. In some embodiments, one or more Hall-Effect sensors may be provided with access to passageway 208 of the vented adaptor 200, and/or to one or more locations along the axial passageway 68 through the staging valve system 42 to monitor successful launch through the staging valve system 42 and into the frac tree 10. In some embodiments, pressure sensors may be included within the staging valve system 42. In some embodiments one or more valve position sensors may be included in the staging valve system 42. In some embodiments, the launch housing 48 may include, or be formed with, one or more transparent portions to permit camera monitoring of the progression of the activation device 41 through the launch passageway 54. The one or more position indicators, sensors and/or cameras provide one or more signals and/or images indicative of the progression of the activation device 41 at the one or more locations. The signals/images can be transmitted to a computer remotely located, for example at the loading station 44. The operator can be confident that the activation device 41 has been successfully launched or, in the event of a problem in the launch, the operator can be provided with useful location information, pressure information and/or valve position information for the problem.

As used herein and in the claims, the word "comprising" is used in its non-limiting sense to mean that items following the word in the sentence are included and that items not specifically mentioned are not excluded. The use of the indefinite article "a" in the claims before an element means that one of the elements is specified, but does not specifically exclude others of the elements being present, unless the context clearly requires that there be one and only one of the elements.

All references mentioned in this specification are indicative of the level of skill in the art of this invention. All references are herein incorporated by reference in their entirety to the same extent as if each reference was specifically and individually indicated to be incorporated by reference. However, if any inconsistency arises between a cited reference and the present disclosure, the present disclosure takes precedence. Some references provided herein are incorporated by reference herein to provide details concerning the state of the art prior to the filing of this application, other references may be cited to provide additional or alternative device elements, additional or alternative materials, additional or alternative methods of analysis or application of the invention.

The terms and expressions used are, unless otherwise defined herein, used as terms of description and not limitation. There is no intention, in using such terms and expressions, of excluding equivalents of the features illustrated and described, it being recognized that the scope of the invention is defined and limited only by the claims which follow. Although the description herein contains many specifics, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the embodiments of the invention.

One of ordinary skill in the art will appreciate that elements and materials other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such elements and materials are intended to be included in this invention. The invention illustratively described herein suitably may be practised in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.