Milling and collecting debris in depleted or sub-hydrostatic wells

Abstract

An approach to milling obstructions in sub-hydrostatic wells uses a bottom hole assembly. The bottom hole assembly includes a tool to collect debris downhole and then mechanically, rather than hydraulically, transport the debris to the surface after milling.

Description

MILLING AND COLLECTING DEBRIS IN DEPLETED OR SUB-HYDROSTATIC WELLSCLAIM OF PRIORITY

[0001] This application claims priority to U.S. Patent Application No. 18 / 584,700 filed on February 22, 2024, the entire contents of which are hereby incorporated by reference.TECHNICAL FIELD

[0002] This specification relates to milling and collecting debris, particularly in depleted or sub-hydrostatic wells.BACKGROUND

[0003] Pressure isolation plugs (“frac plugs”) are frequently used in oil and gas wells to temporarily isolate zones to perform stimulation operations (such as fracturing or acidizing). Once the stimulation process has been completed, the frac plugs are removed to reinstate reservoir zone fluid communication with the wellbore and on to surface for production. Frac plugs can be removed by dissolving (if the frac plugs are made from dissolvable alloys) or milling / drilling.SUMMARY

[0004] This specification describes an approach to milling plugs or other downhole obstructions in wells. This approach combines milling tools with cleanout tools in bottom hole assemblies (BHAs), in particular systems and methods combine a modified venturi junk basket (VJB) with milling toolstrings. This approach enables milling multiple plugs while simultaneously collecting debris downhole. This will reduce the need for good circulation to surface, thus drastically reducing the risk of having milling BHAs stuck due to unrecoverable milled debris / cuttings in the wellbore. This improvement can be particularly significant when using coiled tubing technologies in sub-hydrostatic wells that require use of a foamed circulation / milling / cleanout fluid.

[0005] Coiled tubing deployed milling BHAs used to remove plugs typically use a positive displacement motor and mill bit. A power fluid is circulated down the coiledtubing, through the motor to create rotation to the bit which is forced against the restriction to be milled. The cuttings or swarf are collected as milling proceeds. This approach does not the full column of fluid required to circulate cuttings at a sufficiently high velocity to circulate cuttings out of the wellbore in fluid returns directed up the annulus between coiled tubing and the well casing. Such a full column of fluid may not be achievable if the reservoir is depleted as fluid is lost to permeable reservoir zones below.

[0006] The ongoing collection of cuttings and swarf can avoid the issues that can arise when a plug being milled has a lower pressure zone below the plug. In these situations, the milling BHA can be rotating and creating cuttings when, due to a breakthrough to communicate with the lower zone, circulating fluid is lost. The solid cuttings particles settle and can cause the coiled tubing to become stuck very quickly. In contrast, the present approach collects the cuttings as they are generated and reduces the likelihood that the coiled tubing will become stuck on breakthrough to a lower pressure zone below a plug.

[0007] This approach can provide one or more of the following advantages.

[0008] The described approach to performing milling operations using coiled tubing in live depleted sub -hydrostatic wells ameliorates issues associated with loss of returns or no circulation at all. Improving cleanup and recovery milled debris decreases the risks associated with milling operations. This reduces the likelihood that the coiled tubing and milling bottom hole assembly get stuck, resulting in loss of production, well integrity and even loss of wellbores.

[0009] This approach has the potential to increase operational efficiency and to reduce risk during plug / frac seat milling operations using coiled tubing in subhydrostatic wells, thereby saving considerable operational time. It can also reduce water consumption and reduce the chances of surface equipment washout due to solids recovery.

[0010] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.DESCRIPTION OF DRAWINGS

[0011] Figure 1 A is a schematic view of a bottom hole assembly with a mill and a venturi junk basket tool. Figure IB is a schematic view of the bottom hole assembly in operation.

[0012] Figure 2 is a schematic cross-sectional view of a bottom hole assembly for milling and debris collection.

[0013] Figures 3 A and 3B are schematic views of a bottom hole assembly for milling and debris collection in underbalanced conditions.

[0014] Figure 4 is a flowchart of an associated method.

[0015] Figure 5 is a schematic view of a bottom hole assembly with an under balanced annular junk basket and an electric motor mill.

[0016] Figure 6 is a schematic side view of a bottom hole assembly with an annular VJB and an electric motor mill.

[0017] Figures 7A - 7H are schematic views illustrating the operation of a PDM motor with the rotating VJB.

[0018] Figures 8A and 8B are schematic views of the device for identifying when a junk basket is full.

[0019] Like reference symbols in the various drawings indicate like elements.DETAILED DESCRIPTION

[0020] This specification describes an approach to milling plugs or other downhole obstructions in wells. This approach combines milling tools with cleanout tools in bottom hole assemblies (BHAs), in particular systems and methods combine a modified VJB with milling toolstrings. This approach enables milling multiple plugs while simultaneously collecting debris downhole. This will reduce the need for good circulation to surface, thus drastically reducing the risk of having milling BHAs stuck due to unrecoverable milled debris / cuttings in the wellbore. This improvement can be particularly significant when using coiled tubing technologies in sub-hydrostatic wells that require use of a foamed circulation / milling / cleanout fluid.

[0021] Coiled tubing deployed milling BHAs used to remove plugs typically use a positive displacement motor and mill bit. A power fluid is circulated down the coiledtubing, through the motor to create rotation to the bit which is forced against the restriction to be milled. The cuttings or swarf are collected as milling proceeds. This approach does not the full column of fluid required to circulate cuttings at a sufficiently high velocity to circulate cuttings out of the wellbore in fluid returns directed up the annulus between coiled tubing and the well casing. Such a full column of fluid may not be achievable if the reservoir is depleted as fluid is lost to permeable reservoir zones below.

[0022] Figure 1A is a schematic view of a bottom hole assembly 100 with a mill 110 and a VJB tool 112. The VJB tool 112 is attached to the mill 110 by a junk basket extension module 114. Uphole of the VJB tool 112, the bottom hole assembly 100 includes a downhole through tubing positive displacement motor 116, with a rotor 117 and a stator 118, a bearing section 119, and an external HPCT connector 122. The external HPCT connector 122 attaches the BHA 100 to coiled tubing 124. The coiled tubing 124 is a continuous length of tubing (e g., low-alloy carbon-steel tubing) that can be spooled on a reel for transport, then deployed into a wellbore for the placement of fluids or manipulation of tools during workover and well-intervention operations.

[0023] Typically, it is not possible to run a motor milling BHA in conjunction with a cleanout tool such as a VJB due to the milling torque and forces that would be imparted on the motor during milling operations. However, the BHA 100 is able to combine functionality of milling and cleanout into a single BHA by incorporating using a rotating VJB tool 112 and a rotating VJB extension module 114. In particular, the effective transmission of torque from the motor down to the mill via the VJB can be achieved by means of enhanced material strength requirements or by means of increasing the metal thickness of all components of the BHA. An improved motor bearing section that is able to rotate a long, heavy VJB to prevent excessive wear of the motor bearings. This may require a separate additional bearing section to be added between the Motor and the VJB to dissipate the additional bending moment created by the long rotating VJB assembly.

[0024] The VJB tool 112 circulates a power fluid through a series of nozzles 126 to create a localized drop in pressure that pulls wellbore fluid through a basket 128. When fluid is pumped through the coiled tubing 124 to the VJB tool 112, the nozzles 126direct the flow to the outer diameter of the VJB tool 112 toward its bottom, a vacuum is created in the venturi chamber 130, and fluid and debris is drawn into the bottom of the VJB tool 112. Junk (e.g., cuttings from a plug being milled) is trapped in the basket 128 by a) a filter 132 and b) a set of fingers 134 or a check valve mechanism that closes once flow is stopped. The VJB tool 112 is emptied after the BHA 100 is retrieved to surface.

[0025] This approach enables collection of debris while milling by combining the motor and mill with a debris collection mechanism (in this case a VJB). The VJB design or mechanical strength is upgraded to allow transmission of torque from the motor down to the mill via the VJB.

[0026] The mill 110 is a downhole tool with rough, sharp, extremely hard cutting surfaces for removing metal by grinding or cutting. The mill 110 is selected based on operational requirements for efficient milling of plugs / obstructions and can include but not limited to junk mills, reverse clutch mills, off-centered mills, pilot mills, etc. The mill 110 includes cleaning nozzles 135 but some BHAs have mills that do not include cleaning nozzles.

[0027] The mill 110 is driven by the downhole through tubing positive displacement motor 116. The downhole through tubing positive displacement motor 116 is a positive displacement downhole power drilling tool. It is powered by drilling fluid and coverts fluid pressure into mechanical energy. Drilling fluid is pumped downhole through the coiled tubing 124 and flows through a bypass valve into the downhole through tubing positive displacement motor 116. This flow produces a pressure loss through the motor to push the motor rotor around the stator's axis, this rotation and associated torque are transmitted to the mill 110 by a shaft 136.

[0028] The motorhead assembly 120 includes a hydraulic disconnect 138, a circulation sub 140, and dual flapper check valves 142. The hydraulic disconnect 138 provides a mechanism for disconnecting lower portions or the BHA 100 from the coiled tubing 124 (e.g., if the BHA gets stuck) by simply dropping a ball. The circulation sub 140 provides a flow path from the tool’s inner diameter to the annulus. The dual flapper check valves 142 provide a unidirectional barrier between the well and the coiled tubing

[0029] Some BHAs include a centralizer positioned between the downhole through tubing positive displacement motor 116 and the motorhead assembly 120. The centralizer is a coiled tubing tool designed to position the BHA 100 in a central position in the wellbore. This can be particularly important during operations in deviated wells. Some centralizers are a single-piece centralizer, other centralizers include a central carrier mandrel capable of housing a number of interchangeable, floating slip-over fluted centralizers of different-size outside diameters. The centralizer is chosen with OD sized (single-piece centralizers) or configured (floating fluted centralizers) to match the inside diameter of the tubing in which it is to be run.

[0030] Figure IB is a schematic view of the bottom hole assembly 100 in operation. A plug 144 engaging inside walls of a casing 146 of the well provides a seal separating upper and lower portions of the well. The coiled tubing 124 is used to run the BHA 100 downhole to place the mill 110 in contact with the plug 144. Drilling fluid is pumped downhole to power the downhole motor 116 when the mill 1 10 is still spaced apart from the plug 144. Thus, the mill 110 is rotating when it contacts the plug 144. The resulting cuttings 148 start flow upwards before being sucked into the VJB 112.

[0031] Figure 2 is a schematic cross-sectional view of a BHA 200 for milling and debris collection. The BHA 200 is substantially similar to the BHA 100 and includes a VJB tool 112 attached to a mill 110’, a downhole through tubing positive displacement motor 116, a motorhead assembly 120, and an external HPCT connector 122 attaching the BHA 200 to coiled tubing 124. The VJB tool 112 includes a debris fill indicator 150.

[0032] The circulation sub 140 includes a flexible shaft 152 extending between the through tubing positive displacement motor 116 and the VJB 112. The flexible shaft 152 couples the rotor of the through tubing positive displacement motor 116 to the VJB 112 such that rotation of the rotor rotates the VJB 112. For example, the flexible shaft 152 transmits the rotation from the rotor of the through tubing positive displacement motor 116 which usually follows an eccentric path through to a concentric rotation to the VJB 112. A seal stack 154 downhole around the flexible shaft 152 separating the flexible shaft 152 from the annulus between the outer surface of the BHA 200 and inner walls of the wellbore. Between the through tubing positive displacement motor 116 and the VJB 112, the flexible shaft 152 defines flow ports and a flow restrictor 156.

[0033] Although not shown, the BHA200 will typically include a bearing section 119 with radial and thrust bearings.

[0034] One difference between the BHA 100 and the BHA 200 is that the mill 110’ of the BHA 200 includes features that enable implementation of a reverse bit circulation approach. In particular, the mill 110’ has a large reverse and debris ports not present in the mill 110 of the BHA 100. BHA 100 does not have fluid circulating across the bit. Once milling starts, the debris is suctioned by the VJB by passing from the mill bottom to the VJB window through the annulus. While in the case of BHA 200, suction is provided by the VJB directly through the bit, to reverse circulated debris into the basket. Additionally, in both embodiments, fluid circulation returns up the annulus may also provide debris removal out of the well, thus providing dual cleanup modes for lifting and collecting debris.

[0035] In another difference from the BHA 100, the BHA 200 does not include a junk basket extension module between the VJB tool 112 and the mill 110’. In both the cases, the VJB extension is optional and its use will always be dictated by the amount of debris anticipated during the milling operation. Some implementations of the BHA 200 optionally include a junk basket extension module between the VJB tool 112 and the mill 110’.

[0036] Figures 3A and 3B are schematic views of a bottom hole assembly 300 for milling and debris collection in underbalanced conditions. Figure 4 is a flowchart of an associated method.

[0037] Figure 3A illustrates surface components that are used to position and operate the bottom hole assembly 300. These components also used with the BHA 100 and the BHA 200 but are not shown in the associated figures. The coiled tubing 124 is deployed from a coiled tubing reel 160. The coiled tubing reel 160 is used to run in and retrieve the BHA 300. The coiled tubing reel 160 is connected to a nitrogen pump 162, a fluid pump 163, and a flowback / returns system 164. The coiled tubing 124 runs through a unit 165 and a Christmas tree 166 into the wellbore with the coiled tubing 124 running downhole inside production tubing 168.

[0038] Now referring to Figure 3B, the bottom hole assembly 300 is substantially similar to the bottom hole assembly 200. However, a bottom hole assembly 300 has anannular VJB 112’ rather than an inline VJB. In particular, a Venturi basket flow shroud 170 extends over the motor 116. An uphole end of the Venturi basket flow shroud 170 positioned just downhole of the motorhead assembly 120 and an inflow / circ valve sub 172. Inflow / circulation ports 174 are located just inside the Venturi basket flow shroud 170. The Venturi basket flow shroud 170 extends downhole over the motor 116 to a flow shroud exit 176 near the mill 110. Different shroud approaches may provide a benefit in certain wellbore conditions with varying debris types. The shroud would be harder to rig up as it would be long, making it less suitable for limited rig up height (offshore locations) applications. During operation, debris is collected between the flow shroud 170 and the milling assembly.

[0039] The BHA 300 also includes a stroker tool 177 disposed between the inflow / circulation ports 174 and the motor 116 module. The stroker tool 177 grips the shroud and provides a reaction force downwards to accurately push the mill bit into the item to be milled in a more precise way than moving the CT in hole or out of hole to apply weight on bit.

[0040] The BHA 300 uses an electric motor rather than positive displacement motor. Rather than pumping fluids down the coiled tubing to drive the motor and collect swarfs and debris, the the BHA 300.

[0041] Simultaneously, the circulation of fluids through the coil will also create venturi / suction effect within the VJB installed in the BHA, allowing collection of the created debris within the VJB, thus leaving a debris free wellbore. Once all the plugs, restrictions, etc. are milled or once the VJB is filled with debris, the BHA can be pulled out of hole (POOH) to surface in preparation for further operations.

[0042] Figure 4 is a flowchart of a method 400 of operating the BHA 300 in underbalanced conditions. The method is described with reference to the components discussed with reference to Figures 3A and 3B.

[0043] In operation, the BHA 300 is run in hole (step 410) until it tags (i.e., contacts) the plug 144 or other feature to be milled (step 412). Fluid is pumped downhole through the coiled tubing 124 to the BHA 300. The inflow / circulation valve sub 172 is opened (step 414). If required, lubrication fluid is initially pumped downhole (step 416). The mill bit will always need some lubrication fluid. For example, in thecase of a gas producer, liquid may not be present at the mill bit and a lubrication fluid would be added. Nitrogen gas (N2) is then pumped downhole to displace the lubrication (or other) fluid in the CT (step 418) and the inflow / circulation valve sub 172 is closed (step 420).

[0044] After the inflow / circulation valve sub 172 are closed, the pressure of nitrogen gas in the coiled tubing 124 is reduced to less than hydrostatic (i.e., underbalanced) conditions by bleeding off nitrogen gas at the reel valve 161 (step 422). The mill 110 is rotated by the motor 116 and weight is applied to the bit (step 424) to mill the plug. As milling generates cuttings and debris, underbalanced conditions created by bleeding off the nitrogen suck debris into the coiled tubing string when the inflow / circ valve is opened. After progress is made, the mill is retracted (step 426) and the inflow / circulation ports 174 in the inflow / circulation valve sub 172 are opened to take the returns into the coiled tubing 124. Step 420 through step 428 are repeated until milling of the plug(s) is(are) complete. Once milling is complete, the BHA 300 is pulled out of hole (POOH) while reverse circulating fluid in the system using the fluid pump 163 to remove returns out of the coiled tubing 124.

[0045] Figure 5 is a schematic view of a BHA 500 with an under balanced annular junk basket 510 and an electric motor mill 512. The BHA 500 is substantially similar to the BHA 300. However, the BHA 300 uses an underbalanced CT volume to create debris suction while BHA 500 uses jets in a venturi.

[0046] Figure 6 is a schematic side view of a BHA 600 with an annular VJB 112’. The annular VJB 112’ is similar to the VJB 112 except it has a central drill mechanism in the milling section and an electric motor mill 110. Figures 7A - 7H are schematic views illustrating the operation of a PDM motor with the rotating VJB.

[0047] Although substantially similar to the BHA 100, the BHA 600 includes a modified mill 610 has a central drill bit 612 and an umbrella-type extension module 614 The central drill bit 612 can be activated independently from the mill 610 to drill a through hole in the plug. The central drill bit 612 carries with it the umbrella-type extension module 614 in its undeployed state.

[0048] The central drill bit 612 is triggered after the mill 610 has tagged (i.e., reached) the face of the plug 144 as shown in Figure 7A. The central drill is actuated andretracting from mill and drilling a pilot hole into the plug as shown in Figure 7B. The drill penetrates the plug and carries with it the attached expandable umbrella type extension as shown in Figure 7C. After the central drill bit passes through the plug being drilled, the umbrella-type extension module 614 is deployed to an expanded state by a trigger pressure or electric control from the surface through coiled tubing 124. The umbrella-type extension module 614 is deployed hydraulically or by retraction mechanism like a umbrella up as shown in Figure 7D. The mill 610 is now tagged again to the top of the plug 144 ready for milling while the drill 612 is stopped and stays in place with free relative motion between mill and drill as shown in Figure 7E. Milling proceeds removing material from plug 144 that creates debris that is mostly sucked into the venturi side pocket windows. Some of the debris starts falling below and is collected on the surface of the umbrella structure as shown in Figure 7F. The milling proceeds until the plug 144 is milled completely. Debris not collected in the VJB sits on top of the umbrella structure as shown in Figure 7G. The entire BHA 600 is retracted and pulled out of hole with umbrella structure 614 still in deployed shape to retains the debris during the POOH operation as shown in Figure 7H.

[0049] Figures 8A and 8B are schematic views of a device 800 for identifying when a junk basket is full. The device 800 includes a poppet valve 810 mounted inside the VJB 112 at an uphole end of the VJB 112. The poppet valve 810 includes a seal face 812 disposed at the outlet of the VJB 112. A valve stem 814 is supported by a bracket 816. A spring 818 between a flange 820 of the valve stem 814 and the bracket 816 biases the poppet valve 810 towards its open position (see Figure 8A). As debris fills the VJB 112, the debris compresses the spring 818 and closes the poppet valve 810. Typically, closure of the poppet valve 810 triggers transmission of a signal to the surface indicating that the VJB 112 is full. This approach to identifying when VJBs are full has not been previously necessary. Normally using only a VJB, the risk of getting stuck is minimal because the debris is already present. In this approach, milling creates new debris that increases the chance of getting stuck if the VJB is full and no longer collecting debris.

[0050] An auger 820 (e g., a helical screw) on an outer surface of the body of the rotating VJB 112 biases debris towards window(s). For example, upon clockwiserotation, the auger 820 pushes debris below window uphole and debris above the window downhole towards window to assist debris becoming entrained into basket.Examples

[0051] In some implementations, bottom hole assemblies for milling obstructions in overbalanced wells include: a milling tool comprising a primary bit and a side window or a reverse circulation port; a Venturi junk basket tool rotatably attached to the milling tool; and a downhole high-pressure coiled tubing motor coupled to the milling tool and operable to rotate a bit of the milling tool.

[0052] In an example implementation combinable with any other example implementation, the Venturi junk basket tool is an inline Venturi junk basket tool.

[0053] In an example implementation combinable with any other non-inline Venturi junk basket tool example implementation, the Venturi junk basket tool is an annular Venturi junk basket tool. In some cases, the annular Venturi junk basket tool comprises a flow shroud extending along the downhole high-pressure coiled tubing motor to define an annulus between the motor and the flow shroud.

[0054] In an example implementation combinable with any other example implementation, the milling tool further comprises a secondary drill bit extendable through the primary drill bit and activatable separately from the primary drill bit. In some cases, it further includes an umbrella-type extension coupled to the secondary drill bit, the umbrella-type extension moveable between an undeployed position within the secondary drill bit and a deployed position extending radially outward from the secondary drill bit.

[0055] In an example implementation combinable with any other example implementation, the bottom hole assembly also includes a fill indicator comprising a poppet valve. In some cases, the poppet valve is disposed inside the Venturi junk basket tool at an uphole end of the Venturi junk basket tool.

[0056] In some implementations, methods for milling obstructions in a wellbore include: assembling a bottom hole assembly with: a milling tool comprising a primary bit and a side window or a reverse circulation port; a Venturi junk basket tool rotatably attached to the milling tool; and a downhole high-pressure coiled tubing motor coupled tothe milling tool and operable to rotate a bit of the milling tool; running the bottom hole assembly downhole in the wellbore to an obstruction in the wellbore; and operating the milling tool to remove the obstruction while also operating the Venturi junk basket tool to collect debris generated by operation of the milling tool.

[0057] In an example implementation combinable with any other example implementation, the Venturi junk basket tool is an inline Venturi junk basket tool or an annular Venturi junk basket tool. In some cases, the annular Venturi junk basket tool comprises a flow shroud extending along the downhole high-pressure coiled tubing motor to define an annulus between the motor and the flow shroud.

[0058] In an example implementation combinable with any other example implementation, the method also includes operating a secondary drill bit extendable through the primary drill bit and activatable separately from the primary drill bit. In some cases, it also includes positioning an umbrella-type extension coupled to the secondary drill bit downhole of the obstruction and moving the umbrella-type extension between an undeployed position within the secondary drill bit and a deployed position extending radially outward from the secondary drill bit.

[0059] In an example implementation combinable with any other example implementation, the bottom hole assembly further comprises a fill indicator comprising a poppet valve. In some cases, the poppet valve is disposed inside the Venturi junk basket tool at an uphole end of the Venturi junk basket tool.

[0060] A number of embodiments of the systems and methods have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of this specification. Accordingly, other embodiments are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A bottom hole assembly for milling obstructions in sub-hydrostatic wells, the bottom hole assembly comprising: a milling tool comprising a primary bit and a side window or a reverse circulation port; a junk basket tool rotatably attached to the milling tool; and a downhole high-pressure coiled tubing motor or electric motor coupled to the milling tool and operable to rotate a bit of the milling tool.

2. The bottom hole assembly of claim 1, wherein the junk basket tool is an inline Venturi junk basket tool.

3. The bottom hole assembly of claim 1, wherein the junk basket tool is an annular Venturi junk basket tool.

4. The bottom hole assembly of claim 3, wherein the annular Venturi junk basket tool comprises a flow shroud extending along the downhole high-pressure coiled tubing motor to define an annulus between the motor and the flow shroud.

5. The bottom hole assembly of claim 4, wherein the milling tool further comprises a secondary drill bit extendable through the primary drill bit and activatable separately from the primary drill bit.

6. The bottom hole assembly of claim 5, further comprising an umbrella-type extension coupled to the secondary drill bit, the umbrella-type extension moveable between an undeployed position within the secondary drill bit and a deployed position extending radially outward from the secondary drill bit.

7. The bottom hole assembly of claim 6, further comprising a fill indicator comprising a poppet valve.

8. The bottom hole assembly of claim 7, wherein the poppet valve is disposed inside the Venturi junk basket tool at an uphole end of the Venturi junk basket tool.

9. The bottom hole assembly of claim 4, further comprising a nitrogen gas pump coupled to the coiled tubing and downhole control valves operable to separate an interior of the coiled tubing from the annulus between the motor and the flow shroud.

10. The bottom hole assembly of claim 1, wherein the milling tool further comprises a secondary drill bit extendable through the primary drill bit and activatable separately from the primary drill bit.

11. The bottom hole assembly of claim 10, further comprising an umbrella-type extension coupled to the secondary drill bit, the umbrella-type extension moveable between an undeployed position within the secondary drill bit and a deployed position extending radially outward from the secondary drill bit.

12. The bottom hole assembly of claim 1, further comprising a fill indicator comprising a poppet valve.

13. The bottom hole assembly of claim 12, wherein the poppet valve is disposed inside the Venturi junk basket tool at an uphole end of the Venturi junk basket tool.

14. A method for milling obstructions in a wellbore, the method comprising: assembling a bottom hole assembly comprising: a milling tool comprising a primary bit and a side window or a reverse circulation port; a Venturi junk basket tool rotatably attached to the milling tool; and a downhole high-pressure coiled tubing motor or electric motor coupled to the milling tool and operable to rotate a bit of the milling tool; running the bottom hole assembly downhole in the wellbore to an obstruction in the wellbore; and operating the milling tool to remove the obstruction while also operating the Venturi junk basket tool to collect debris generated by operation of the milling tool.

15. The method of claim 14, wherein the Venturi junk basket tool is an inline Venturi junk basket tool.

16. The method of claim 14, wherein the Venturi junk basket tool is an annular Venturi junk basket tool.

17. The method of claim 16, wherein the annular Venturi junk basket tool comprises a flow shroud extending along the downhole high-pressure coiled tubing motor to define an annulus between the motor and the flow shroud.

18. The method of claim 14, further comprising operating a secondary drill bit extendable through the primary drill bit and activatable separately from the primary drill bit.

19. The method of claim 18, further comprising positioning an umbrella-type extension coupled to the secondary drill bit downhole of the obstruction and moving the umbrella-type extension between an undeployed position within the secondary drill bit and a deployed position extending radially outward from the secondary drill bit.

20. The method of claim 14, wherein the bottom hole assembly further comprises a fdl indicator comprising a poppet valve disposed inside the Venturi junk basket tool at an uphole end of the Venturi junk basket tool.

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