Patent Description:
A well system may include a work string deployed downhole within a wellbore. The work string may include various tools, for example but not limited to agitator tools for applying a vibration or other agitating motion to the work string, check valves that may act as a pressure barrier, and tools for pulsating a fluid pumped from a surface of the wellbore. These tools may positioned in a bottom hole assembly ("BHA") of the work string or elsewhere along the work string. The inclusion of these tools on the BHA can increase the length of the BHA and can increase the cost of the BHA. In some well systems, the need for a tool, including but not limited to an agitator tool, check valve, or fluid pulsation tool may not be apparent during the planning of the well system and the work string may not include a certain tool when it is originally designed and deployed downhole. Thereafter, during the life of the well it may be desirable to have such a tool on the BHA or elsewhere along the work string. In some instances, a work string may include a tool when it is originally positioned downhole but the tool may become inoperable during the lifetime of the well. It may be desirable to provide a tool on the working string after the work string has initially been deployed downhole without having to remove the work string from the wellbore.

<CIT> discloses a dart configured to target a location in a wellbore. The dart may comprise a body conveyable through a tubing string, the body defining a central flow bore from an upper end to a lower end of the wellbore dart where the central flow bore is adapted to allow circulation of fluid is provided.

<CIT> discloses an apparatus and method for launching a plurality of activation devices into a wellbore from a surface from which the wellbore extends to perform a downhole operation.

According to a first aspect of the present invention, there is provided a pump down intervention tool according to Claim <NUM>.

According to a second aspect of the present invention, there is provided a pump down assembly according to Claim <NUM>.

Certain aspects and embodiments of the present disclosure describes a device and an apparatus to enable pumping one or more intervention tools downhole through a tubing string. The intervention tools that may be pumped downhole through a work string (or tubing string) according to various aspects of the present disclosure are hereinafter referred to as "darts". The work string may include coiled tubing or jointed pipes. The dart may be pumped downhole through the coiled tubing or the jointed pipes to a desired depth. The dart can be pumped downhole after the work string's initial deployment such that a preconfigured tool need not be installed on the work string initially; instead, the dart can provide the desired functionality downhole at a later time after the initial deployment of the work string downhole.

The dart may be configured to produce a variety of effects based on the internal configuration of a downhole tool included within the dart. In some aspects, the dart may include a housing, for example a cylindrical housing, with various downhole tools that may be inserted within the housing. In some aspects, various darts may each include different downhole tools that are integral with the dart housing (i.e., not separately removable from the dart housing). The dart may include tools such as check valve or an agitator tool (including but not limited to a fluidic pulsation device), though in some aspects, the dart may include other tools or functions.

These illustrative examples are given to introduce the reader to the general subject matter discussed here and are not intended to limit the scope of the disclosed concepts. The following describes various additional aspects and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative aspects. The following uses directional descriptions such as "above," "below," "upper," "lower," "left," "right," "downhole," "up-hole," etc. in relation to the illustrative aspects as they are depicted in the figures, the downhole direction being toward the toe of the well. Like the illustrative aspects, the numerals and directional descriptions included in the following should not be used to limit the present disclosure. Furthermore, the following uses the term "or" to denote any combination of options separated by the term "or", including combinations in which only one of the options is utilized and combinations in which more than one (and in some cases, all) of the options are utilized.

-<FIG>AB depict a well system <NUM> including a bore that is a wellbore <NUM> extending from a surface <NUM> through various earth strata. The wellbore <NUM> has a substantially vertical section <NUM>. In some aspects, the wellbore <NUM> may also include a substantially horizontal section. Some length of the substantially vertical section <NUM> may include a casing string <NUM>. The substantially vertical section <NUM> extends through a hydrocarbon bearing subterranean formation <NUM>.

A tubing string (or work string) <NUM> extends from the surface <NUM> within wellbore <NUM>. The tubing string <NUM> is shown in <FIG> as a coiled tubing extending from a coiled tubing reel <NUM> at the surface <NUM> of the wellbore <NUM>. In some aspects, the tubing string <NUM> may include a series of jointed pipes. A downhole portion of the tubing string <NUM> is the BHA <NUM>.

<FIG> depict an intervention tool or dart <NUM> deployed within an inner diameter "ID" of the tubing string <NUM>. The dart <NUM> is shown landed a particular location on the tubing string <NUM> but may be landed in other regions of the tubing string <NUM> in other aspects. In some aspects, the dart <NUM> may be landed in the BHA <NUM>. The dart <NUM> may include a tool, for example an interventional tool including but not limited to an agitator tool (including but not limited to a fluidic pulsation device) or a check valve. The dart <NUM> may include a housing <NUM> within which a tool <NUM> (e.g. a downhole tool) may be positioned. The housing <NUM> may be cylindrical in shape, though in some aspects other shapes may be used. The housing <NUM> may have a maximum outer diameter that determines a positon along a length of the tubing string <NUM> at which the dart <NUM> may be landed.

In some aspects, the tool <NUM> may be inserted or removed from the housing <NUM> while in other aspects the tool <NUM> may be uncoupleable from (including but not limited to integral with) the housing <NUM>. In some aspects, the dart <NUM> may have a tapered end <NUM> that may be positionable downhole. The dart <NUM> may also include an opening or inlet on a first end and an opening or outlet a second end for defining a flow path through the dart <NUM>.

In some aspects, the dart <NUM> may also include a locking mechanism that is sized and shaped to engage or mate with a receiving feature on the inner surface of the tubing string <NUM>. The locking mechanism may include but is not limited to a locking ring that may engage a profile in the tubing string <NUM> within which it is deployed. For example, the locking ring may engage with the BHA to secure the dart <NUM> in place on the BHA. In some aspects the locking ring may allow bespoke engagement of the dart <NUM> downhole within the tubing string, for example within a receiving sub of the tubing string <NUM>. The locking mechanism may prevent the dart <NUM> from moving back up-hole or otherwise disengaging with the tubing string <NUM>. The locking mechanism may be positioned at any point along a length of the dart <NUM>.

As shown in <FIG>, the dart <NUM> also includes multiple flanges, blades, or cups <NUM> that may provide a surface area exposed to a fluid flow when the dart <NUM> is pumped downhole. The cups <NUM> may extend around an entire circumference of the housing <NUM> though in some aspects the cups <NUM> may only extend partially around the circumference of the housing <NUM>. The cups <NUM> may comprise a semi-flexible material to accommodate an internal weld flash on the tubing string <NUM>, or a more rigid material allowing a sealing around the weld flash on the tubing string <NUM>.

The dart <NUM> also include pads <NUM> on the housing <NUM> which may allow the dart <NUM> to move within the tubing string <NUM> in a downhole direction but prevent movement of the dart <NUM> in an up-hole direction. In other words, the pads <NUM> may be mono-directional slips or pads that allow only a single direction of motion of the dart <NUM>. These pads <NUM> may aid in setting the dart <NUM> at any depth within the tubing string <NUM> without using a secondary locking mechanism. In this way the dart <NUM> may be used to provide a barrier seal above a leak, pinhole, or other damaged point in the tubing string <NUM> at any depth.

In some aspects, the dart <NUM> may be coupleable to an additional dart. The dart <NUM> may include a feature, for example a locking feature that engages with a surface or region of an additional dart when the darts are positioned within the tubing string <NUM>.

In some aspects, the tool <NUM> of the dart <NUM> may include a check valve for placement or replacement of a check valve in the tubing string <NUM>. The check valve may be, but is not limited to, a back pressure valve to provide a barrier to pressure. The back pressure valve may permit a fluid or pressure from above to pass through the dart <NUM> to enable pumping of flow through the tubing string <NUM> below the position of the dart <NUM>. In some aspects, the check valve may be a flapper cartridge that may provide a one-way flapper valve for allowing a flow or pressure to pass through the check valve from above but sealing against a flow or pressure from below the dart <NUM>.

In some aspects, the tool <NUM> of the dart <NUM> may include an agitator tool. The agitator tool may create a fluidic hammer or vibrating effect on the tubing string <NUM> for extended reach or freeing the stuck tubing string <NUM>. In some aspects, the agitator tool may create downhole pressure pulses for pushing fluids or treatments into the formation or behind the casing, or loosening or dislodging wellbore deposits or debris, or other suitable purposes.

In some aspects, the agitator tool of the tool <NUM> may include an oscillatory piston with inner and outer ports that may align and misalign to create a build-up and subsequent release of pressure through the inner and outer ports relative to their alignment. The movement between the alignment and misalignment of the inner and outer ports can produce a fluidic hammering effect. In some aspects, the agitator tool of the tool <NUM> may include a j-slot or fluidic oscillator, for example, a down-jet fluidic oscillator, a fan-jet fluidic oscillator, or a side-jet fluidic oscillator for creating pulses in a fluid flow through the dart <NUM>. The tool <NUM> including a fluidic oscillator can provide a rapid cycling between positions in response to a continuous fluid flow for altering the alignment of a flow port through the dart <NUM> for creating pulses in the outflow of the fluid through the dart <NUM> via the flow port.

The dart <NUM> may be deployed downhole via a launching apparatus <NUM> coupled to the coiled tubing plumbing <NUM>, an aspect of which is described further below with reference to <FIG> and <FIG>.

<FIG> depicts an isometric view of a dart <NUM> including a check valve <NUM> according to an aspect of the present disclosure. The dart <NUM> includes a housing <NUM> shown as see through to provide visual access to the check valve <NUM> in the figure. The housing <NUM> includes an outer surface <NUM> and an inner surface <NUM>. The inner surface <NUM> of the dart <NUM> may define a first opening (or inlet) <NUM> in a first end <NUM> of the dart <NUM>. The inner surface <NUM> may also define a second opening (or outlet) <NUM> in a second end <NUM> of the dart <NUM>. The first and second openings <NUM>, <NUM> may define a flow path through the dart <NUM> through which a fluid may flow. The second opening <NUM> may permit fluid to exit the housing <NUM>. The check valve <NUM> is positioned within the flow path through the dart <NUM>. The second end <NUM> of the dart <NUM> may be tapered. The tapered shape of the second end <NUM> may identify for a user a downhole end of the dart <NUM> and may provide a smaller outer diameter to aid in allowing the dart <NUM> to push past an inner diameter restriction within the tubing string it is deployed in.

In some aspects the tapered shaped of the second end <NUM> may act as a locking mechanism in that it is sized and shaped to engage or mate with a receiving feature on the inner surface of the tubing string within which the dart <NUM> is deployed. In some aspects, the dart <NUM> may include a separate locking mechanism such as a locking ring <NUM> that may engage a profile in the tubing string within which it is deployed. In some aspects the locking ring <NUM> may allow bespoke engagement of the dart <NUM> downhole within the tubing string, for example within a receiving sub of the tubing string. The locking mechanism, for example locking ring <NUM> may prevent the dart <NUM> from moving back up-hole or otherwise disengaging with the tubing string. The locking mechanism may be positioned proximate the first end <NUM>, the second end <NUM> or at any point along a length of the dart <NUM>.

The dart <NUM> also includes multiple flanges, blades, or cups <NUM> positioned on the outer surface <NUM>. The cups <NUM> may extend around an entire circumference of the housing <NUM> as shown in <FIG>, though in some aspects the cups <NUM> may only extend partially around the circumference of the housing <NUM>. The cups <NUM> may comprise a semi-flexible material to accommodate an internal weld flash on a coiled tubing within which the dart <NUM> is deployed, or a more rigid material allowing a sealing around the weld flash on the coiled tubing.

The check valve <NUM> of dart <NUM> may include a spring <NUM> that is coupled to a piston <NUM>. The piston <NUM> may be sized and shaped at a sealing end <NUM> to seal against an inlet <NUM> of the check valve <NUM>. The piston <NUM> has an open position in which the piston <NUM> move downwards and compresses the spring <NUM> in response to a sufficient pressure from above the piston <NUM>. In the open position, fluid may flow through the first end <NUM> of the dart <NUM>, through the inlet <NUM> of the check valve <NUM> and out an outlet <NUM> of the check valve and out the second end <NUM> of the dart <NUM>. In other words, fluid may flow through the flow path in the dart <NUM> when the piston <NUM> is in the open position. The piston <NUM> has a closed position in which the spring <NUM> extends such that the sealing end <NUM> of the piston <NUM> seals against the inlet <NUM> of the check valve <NUM> and prevent fluid flow through the inlet <NUM>. The piston <NUM> may move to the closed position in response to a lack of sufficient pressure from above the piston <NUM> to compress the spring <NUM>. In the closed position, the piston <NUM> prevents fluid from flowing through the check valve <NUM> and thus prevents fluid from flowing through the flow path in the dart <NUM>.

In some aspects, the dart <NUM> may include a check valve <NUM> that is a flapper cartridge including for example a one way flapper valve or other similar valve that allows for a flow or a pressure from above the check valve <NUM> to pass through to below the check valve <NUM>, but sealing or preventing a flow or a pressure from below the check valve <NUM> from pass through to above the check valve <NUM>.

<FIG> depicts a cross-sectional side view of a dart <NUM> that includes an agitator tool <NUM> according to an aspect of the present disclosure. The dart <NUM> includes a housing <NUM> having an outer surface <NUM> and an inner surface <NUM>. The inner surface <NUM> of the dart <NUM> may define a first opening (or inlet) <NUM> in a first end <NUM> of the dart <NUM>.

The agitator tool <NUM> of dart <NUM> may include a spring <NUM> that is coupled to a tube or piston <NUM>. The housing <NUM> includes ports <NUM> that provide fluid communication between an inner region <NUM> of the housing <NUM> and an outer region <NUM> of the housing <NUM>. The piston <NUM> has an open position and a closed position. In the closed position (shown in broken lines in <FIG>) the piston <NUM> is positioned within the housing <NUM> such that the piston <NUM> blocks the ports <NUM> of the housing and prevents fluid flow from the inner region <NUM> of the housing <NUM> to the outer region <NUM> of the housing <NUM> via the ports <NUM>. The pressure above the piston <NUM> may increase as fluid is pumped into the work string within which the dart <NUM> is launched when the dart is in the closed position. In response to a sufficient amount of pressure above the piston <NUM>, the piston <NUM> may move downhole, compressing the spring <NUM> until the piston <NUM> is positioned at least partially below the ports <NUM>. The piston <NUM> is in the open position (as shown in <FIG>) when the piston <NUM> is positioned at least partially below the ports <NUM> such that fluid may flow through the first end <NUM> of the dart <NUM> and exit the housing <NUM> via the ports <NUM>. As the fluid exits the dart <NUM> via the ports <NUM>, the pressure above the piston <NUM> may decrease and the spring <NUM> may force the piston <NUM> back up-hole to the closed position in which the ports <NUM> are blocked by the piston <NUM>.

The spring <NUM> may not compress in response to a pressure above the piston <NUM> until the dart <NUM> has bottomed out or engaged with a BHA <NUM>, as shown in <FIG>. The movement of the piston <NUM> between the open and closed positions can impart an impact force or a vibrational force, i.e. an agitation motion. The cycling of the piston <NUM> between the open and the closed position as the pressure builds or bleeds off, can act as a fluidic hammer, can provide a direct impact force, or can provide a vibrational agitating motion, for example for freeing a stuck tubing downhole. In some aspects, the dart <NUM> may be used for providing downhole pressure pulses via the agitator tool <NUM> for pushing a fluid or a treatment into the formation, behind a casing, or for loosening or dislodging wellbore deposits or debris. The agitation frequency of the dart <NUM> can be achieved based on the specific configurations of the housing <NUM>, the piston <NUM>, the spring <NUM>, and the ports <NUM>.

In some aspects, a dart, for example dart <NUM>, may include another aspect of an agitator tool. <FIG> depicts an isometric drawing of a dart <NUM> according to an aspect of the present disclosure. The dart <NUM> includes a housing <NUM> that is shown in <FIG> as see-through to provide visual access to an agitator tool <NUM> positioned within the housing <NUM>. The dart <NUM> also includes cups <NUM> for aiding in forcing the dart <NUM> downhole in response to a fluid flow or pressure from above the dart <NUM>. A first end <NUM> of the dart <NUM> includes an opening <NUM> in the housing <NUM> for allowing a fluid flow to enter an inner region of the dart <NUM>.

A second end <NUM> of the dart <NUM>, opposite the first end <NUM>, includes an opening (or outlet) <NUM>. The second end <NUM> of the dart <NUM> may be a tapered end and may be the end of the dart <NUM> that is positioned downhole when the dart <NUM> is inserted into a tubing string (e.g. a coiled tubing or jointed pipes). The second end <NUM> of the dart <NUM> may be sized and shaped to engage with a BHA. In some aspects, the dart <NUM> may include a locking feature or mechanism for engaging the dart <NUM> in locking engagement with a BHA.

The agitator tool <NUM> may include a rotatable valve <NUM>, for example but not limited to an impeller, a rotor, a stator, or other similar rotating valve that may spin as fluid is passed through the dart <NUM>. The rotatable valve <NUM> may rotate relative to the housing <NUM>, for example as a fluid passes between the rotatable valve <NUM> and the housing <NUM> the fluid may induce rotation of the rotatable valve <NUM>. For example, as shown in <FIG>, the rotatable valve <NUM> may include a plurality of blades <NUM> positioned about an outer surface of the rotatable valve <NUM>. The impeller blades <NUM> may cause the rotatable valve <NUM> to rotate as the fluid passes between a region between an outer surface the rotatable valve <NUM> and an inner surface of the housing <NUM>. In some aspects, the rotatable valve <NUM> may include ridges or other mating features on the outer surface of the rotatable valve <NUM> that are matched by an interfacing profile on the inner surface of the housing <NUM> for defining the movement of the rotatable valve <NUM> relative the housing <NUM>. The fluid passing in the region between the outer surface of the rotatable valve <NUM> and the inner surface of the housing <NUM> can induce rotation based on pressure build-up in that region. The agitator tool <NUM> may also include a plate <NUM> positioned at a lower end <NUM> of the rotatable valve <NUM>. The plate <NUM> includes an opening (or port) <NUM>. The opening <NUM> is sized, shaped, and positioned such that as the rotatable valve <NUM> spins, the opening <NUM> in the plate aligns and misaligns with the outlet <NUM> in the second end <NUM> of the housing <NUM> of the dart <NUM>. Thus, a fluid may enter the dart <NUM> through the opening <NUM> in the first end <NUM> of the dart <NUM>, the fluid may flow through the rotatable valve <NUM> and in doing so may cause the rotation of the rotatable valve <NUM>, the fluid may flow through the opening <NUM> in the plate <NUM> and may exit the housing <NUM> through the outlet <NUM> in the second end of the housing <NUM>. As the opening <NUM> in the plate <NUM> aligns and misaligns with the outlet <NUM> in the housing <NUM> as the rotatable valve <NUM> spins, the outflow of fluid through the port <NUM> may pulsate. This oscillating flow of fluid through the dart <NUM> as the opening <NUM> in the plate <NUM> aligns and misaligns with the outlet <NUM> in the housing <NUM> can act as an agitator for providing a direct impact force or a vibrational agitating motion, for example for freeing a stuck tubing downhole. In some aspects, the dart <NUM> may be used for providing downhole pressure pulses via the agitator tool <NUM> for pushing a fluid or a treatment into the formation, behind a casing, or for loosening or dislodging wellbore deposits or debris.

In some aspects, a spring mechanism may be added to the agitator tool <NUM> to add an element of a physical hammering effect to provide additional intensity to the force provided by the agitating motion of the agitator tool <NUM>.

Darts according to aspects of the present disclosure, for example but not limited to darts <NUM>, <NUM>, <NUM>, and <NUM>, may be launched downhole by inserting a dart directly into the work string flow path. For example, in some aspects, a point in the flow iron may be opened and the dart may be pushed into the flow path by hand. In some aspects, the dart may be launched downhole via a launch assembly. For example, in aspects in which the dart is launched into a coiled tubing, the dart may be launched via a launch assembly. The launch assembly may improve operational efficiency and safety in some aspects. For example, in some aspects a chemical or other substance may be pumped through the coiled tubing (or jointed pipes) and it may be desirable to use a launching assembly (e.g., launching assembly <NUM> or <NUM> shown below in <FIG> and <FIG>) to minimize a user's exposure to the chemicals being pumped through the coiled tubing.

<FIG> depicts a schematic diagram of a launch assembly <NUM> for launching darts <NUM> and <NUM> into a coiled tubing reel <NUM> at a surface of a wellbore. The darts <NUM> and <NUM> may be any type of dart, including but not limited darts <NUM>, <NUM>, <NUM>, and <NUM>. The launch assembly <NUM> includes a double wye tubing section ("double wye") <NUM> that is connected to the coiled tubing reel <NUM>. In some aspects, only a single wye may be used. The double wye <NUM> is connected to a flow iron <NUM> of the coiled tubing reel <NUM>. The double wye <NUM> is connected to the flow iron <NUM> downstream from a primary valve <NUM> of the coiled tubing reel <NUM>. The flow iron <NUM> may have an inner diameter "ID" that is, in some aspects, approximately <NUM> inches (<NUM>). The double wye <NUM> may have an inner diameter that is less than the inner diameter of the flow iron <NUM>, for example the arms of the double wye <NUM> may have in inner diameter in some aspects of approximately <NUM> inch (<NUM>). In some aspects, the double wye <NUM> is coupled to the flow iron <NUM> beyond or past the last hard <NUM>-degree turn of the reel plumbing set-up of the coiled tubing reel <NUM>. The flow iron <NUM> is connected to a coiled tubing (not shown) at a location further downstream from the double wye <NUM>.

A chamber <NUM> within which the dart <NUM> is positioned may be coupled at a first end <NUM> to a first arm <NUM> of the double wye <NUM>. A chamber <NUM> within which the dart <NUM> is positioned may be coupled at a first end <NUM> to a second arm <NUM> of the double wye <NUM>. The darts <NUM>, <NUM> may be preloaded within the respective chambers <NUM>, <NUM> in some aspects. In some aspects, the chambers <NUM>, <NUM> may be loaded or reloaded with a dart, for example darts <NUM>, <NUM>. The chamber <NUM> containing the dart <NUM> may include a gate (e.g., a flapper, check valve, or a pin) <NUM> for retaining the dart <NUM> within the chamber <NUM>. Similarly, the chamber <NUM> may include a gate (e.g., a flapper, check valve, or a pin) <NUM> for retaining the dart <NUM> within the chamber <NUM>.

A flow line <NUM> may extend between a second end <NUM> of the chamber <NUM> and the flow iron <NUM>. A valve <NUM> may be positioned within the flow line <NUM> for controlling a pressure applied to the chamber <NUM>. The gate <NUM> in the chamber <NUM> may actuate to an open position in response to the valve <NUM> being positioned in an open position. The valve <NUM> may be actuated into the open position in response to a pressure applied by a line <NUM>. The valve <NUM> may be controllable using hydraulic, pneumatic, electric, fiber optic, manual, wireless or other control mechanisms. The chamber <NUM> may be exposed to a pressure from the flow iron <NUM> in response to the valve <NUM> being in the open position. The pressure applied to the chamber <NUM> by the flow iron <NUM> may actuate the gate <NUM> into an open position. With the gate <NUM> in the open position and with the pressure applied to the chamber from the flow iron <NUM>, the dart <NUM> may be forced from the chamber <NUM> and into the flow iron <NUM>, which is coupled to the coiled tubing. The dart <NUM> may thereby enter the coiled tubing and be forced downhole in the coiled tubing via the pumping of fluid through the coiled tubing. In some aspects, the launch assembly <NUM> may not include the gate <NUM> or <NUM>.

Another flow line <NUM> may extend between a second end <NUM> of the chamber <NUM> and the flow iron <NUM>. Another valve <NUM> may be positioned within the flow line <NUM> for controlling a pressure applied to the chamber <NUM>. The gate <NUM> in the chamber <NUM> may actuate to an open position in response to the valve <NUM> being positioned in an open position. The valve <NUM> may be actuated into the open position in response to a pressure applied by a line <NUM>. The valve <NUM> may be controllable using hydraulic, pneumatic, electric, fiber optic, manual, wireless or other control mechanisms. The chamber <NUM> may be exposed to the pressure from the flow iron <NUM> in response to the valve <NUM> being in the open position. The pressure applied to the chamber <NUM> may actuate the gate <NUM> into an open or release position. With the gate <NUM> in the open position and with the pressure applied to the chamber from the flow iron <NUM>, the dart <NUM> may be forced from the chamber <NUM> and into the flow iron <NUM>, which is coupled to the coiled tubing. The dart <NUM> may thereby enter the coiled tubing and be forced downhole in the coiled tubing via the pumping of fluid through the coiled tubing. Thus, the darts <NUM>, <NUM> may be launched into a coiled tubing via the launch assembly <NUM>, which is connected to the coiled tubing reel downstream of the primary valve of the coiled tubing reel and downstream from the last hard <NUM>-degree turn in the coiled tubing reel set-up.

The darts <NUM>, <NUM> may be launched in a desired order in response to actuating one of the valves <NUM>, <NUM> first. In some aspects, the launch assembly <NUM> may not include the gate <NUM> or <NUM>. In some aspects in which one or more of the gates <NUM> or <NUM> are check valves, the chambers <NUM>, <NUM> may be reloaded with additional darts by closing the first or second valves <NUM>, <NUM> so that no pressure flows from the flow iron <NUM> to the chambers <NUM>, <NUM>. The chambers <NUM>, <NUM> may be reloaded with a dart via a cap or other access point in the chambers <NUM>, <NUM>.

<FIG> depicts a schematic diagram of a launch assembly <NUM> for launching darts <NUM> and <NUM> into a coiled tubing reel <NUM> at a surface of a wellbore. The launch assembly <NUM> includes a single wye tubing section ("single wye") <NUM> that is connected to the coiled tubing reel <NUM>. The single wye <NUM> is connected to a flow iron <NUM> of the coiled tubing reel <NUM>. The single wye <NUM> is connected to the flow iron <NUM> downstream from a primary valve <NUM> of the coiled tubing reel <NUM>. The flow iron <NUM> may have an inner diameter "ID" that is in some aspects approximately <NUM> inches (<NUM>). The single wye <NUM> may have a smaller inner diameter than the flow iron <NUM>, for example, the single wye <NUM> may in some aspects have an inner diameter of approximately <NUM> inch (<NUM>). In some aspects, the single wye <NUM> is coupled to the flow iron <NUM> beyond or past the last hard <NUM>-degree turn of the reel plumbing set-up of the coiled tubing reel <NUM>. The flow iron <NUM> is connected to a coiled tubing (not shown) at a location further downstream from the single wye <NUM>.

The launch assembly <NUM> includes an arm <NUM> that extends from the flow iron <NUM>. A first chamber <NUM> is coupled to the arm <NUM> of the single wye <NUM>. The dart <NUM> is positioned within the first chamber <NUM>. A gate (e.g., a flapper, check valve, or a pin) <NUM> is positioned within the first chamber <NUM> for retaining the dart <NUM> in the first chamber <NUM>. A second chamber <NUM> is also coupled to the arm <NUM> and positioned adjacent the first chamber <NUM>. The dart <NUM> is positioned within the second chamber <NUM>. A gate (e.g., a flapper, check valve, or a pin) <NUM> is positioned within the second chamber <NUM> for retaining the dart <NUM> in the second chamber <NUM>. Though two chambers <NUM>, <NUM> are depicted in the launch assembly <NUM>, in some aspects more or fewer chambers may be used.

A first valve <NUM> may be positioned within a flow line <NUM> extending between the first chamber <NUM> and the flow iron <NUM>. A second valve <NUM> may be positioned within the flow line <NUM> between the second chamber <NUM> and the flow iron <NUM>. A cap <NUM> may be positioned on an end of the single wye <NUM> to provide access to the first chamber <NUM> and the second chamber <NUM> for loading or reloading a dart within the chambers. The darts <NUM>, <NUM> may be launched sequentially, with dart <NUM> launched first and the dart <NUM> being launched second.

The first valve <NUM> may be actuated into an open position via a line <NUM>. The first valve <NUM> may be controllable using hydraulic, pneumatic, electric, fiber optic, manual, wireless or other control mechanisms. A pressure from the flow iron <NUM> may be applied to the first chamber <NUM> when the first valve <NUM> is in the open position. The pressure may force the dart <NUM> out of the first chamber <NUM>, for example, the pressure may also force the gate <NUM> to move to an open or release position to permit the dart <NUM> to exit out of the first chamber <NUM> and enter the flow iron <NUM>.

The second valve <NUM> may be actuated into an open position via a line <NUM>. The second valve <NUM> may be controllable using hydraulic, pneumatic, electric, fiber optic, manual, wireless or other control mechanisms. A pressure from the flow iron <NUM> may be applied to the second chamber <NUM> when the second valve <NUM> is in the open position. The pressure may force the dart <NUM> out of the second chamber <NUM>, for example, the pressure may also force the gate <NUM> to move to an open or release position as the dart <NUM> moves out of the first chamber <NUM> and enters the flow iron <NUM>. The darts <NUM>, <NUM> may then enter the coiled tubing via the flow iron <NUM>.

In an aspect in which the gates <NUM>, <NUM> are a check valve, the chambers <NUM>, <NUM> may be reloaded with additional darts by closing the first and second valves <NUM>, <NUM> so that no pressure flows from the flow iron <NUM> to the first and second chambers <NUM>, <NUM> when the cap <NUM> is opened.

In some aspects, a launching assembly may utilize a push rod system to push a dart into the tubing string. In some aspects, a launching assembly may use a separately affixed pneumatic line to force a dart into the tubing string. In addition, in some aspects the launching assembly may be used to launch standard darts or balls that are not described herein.

Claim 1:
A pump down intervention tool (<NUM>) comprising:
a housing (<NUM>) including a first end (<NUM>) and a second end (<NUM>), the housing (<NUM>) including an outer surface (<NUM>) and an inner surface (<NUM>), wherein the inner surface (<NUM>) defines a flow path extending from the first end (<NUM>) to the second end (<NUM>) of the housing (<NUM>);
a downhole tool (<NUM>) positioned within the flow path of the housing (<NUM>); and
a plurality of cups (<NUM>) coupled to the outer surface (<NUM>) of the housing (<NUM>) and each of the cups (<NUM>) of the plurality of cups (<NUM>) extending at least partially around a circumference of the outer surface (<NUM>) of the housing (<NUM>) for providing a surface area exposed to a flow of a pumped fluid for aiding in downhole propagation of the pump down intervention tool (<NUM>);
wherein the downhole tool (<NUM>) further comprises a check valve (<NUM>); and
wherein the check valve (<NUM>) is a back pressure valve including a sealing piston (<NUM>) coupled to a spring (<NUM>), and wherein the sealing piston (<NUM>) may be positioned in an open position in response to a sufficient pressure from above the piston (<NUM>) to compress the spring (<NUM>) in which fluid may flow through the flow path and may exit the housing (<NUM>) via an outlet (<NUM>) in the second end (<NUM>) of the housing (<NUM>), and wherein the check valve (<NUM>) may be positioned in a closed position in response to a lack of sufficient pressure from above the piston (<NUM>) to compress the spring (<NUM>) in which fluid is preventing from flowing through the flow path and exiting the outlet (<NUM>) in the second end (<NUM>) of the housing (<NUM>).