Patent Publication Number: US-10767447-B2

Title: Downhole radial cleanout tool

Description:
FIELD 
     The present disclosure relates generally to a downhole tool for cleaning the interior of a wellbore. 
     BACKGROUND 
     Hydrocarbon producing wells may simultaneously produce water, which in turn may result in the development of inorganic scales being deposited on perforations, casing, production tubulars, and other downhole equipment. If left unattended, the scaling may adversely impact well performance. 
     A number of technologies exist for removing scaling without damaging the wellbore, tubing, or reservoir. For example, the scaling may be removed mechanically or dissolved chemically. In tubing, it may be feasible to simply pull the tubing from the wellbore to mill out scale deposit. Where scaling is in the wellbore, such an approach may not be feasible. Where milling is not practicable, other types of cleaning systems may be deployed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative embodiments of the present disclosure are described in detail below with reference to the attached drawing figures, which are incorporated by reference herein, and wherein: 
         FIG. 1A  is a schematic, side view of a cleanout tool deployed within a wellbore of a subterranean well; 
         FIG. 1B  is a schematic, side view of a cleanout tool deployed within a wellbore of a sub-sea well; 
         FIG. 2  is a schematic, cross-section view of a cleanout tool having a rotatable housing and a filter disposed therein; 
         FIG. 2A  is a section view of a plurality of nozzles disposed within the cleanout tool of  FIG. 2 , taken along the section line  2 A- 2 A; 
         FIG. 3  is a schematic, cross-section view of an alternative embodiment of a cleanout tool, analogous to the cleanout tool pictured in  FIG. 2 ; and 
         FIG. 4  is a schematic, cross-section view of another alternative embodiment of a cleanout tool, analogous to the cleanout tool pictured in  FIG. 2 . 
     
    
    
     The illustrated figures are only exemplary and are not intended to assert or imply any limitation with regard to the environment, architecture, design, or process in which different embodiments may be implemented. 
     DETAILED DESCRIPTION 
     The present disclosure relates to a downhole cleanout tool having a tool housing having a fluid inlet and a fluid outlet, and a filter disposed between the fluid inlet and the fluid outlet. The tool also includes a pump having a pump inlet and a pump outlet, the pump being fluidly coupled to at least the fluid inlet to motivate fluid across the filter. In addition, the tool includes a rotatable housing having at least one nozzle disposed therein, the nozzle being fluidly coupled to the pump outlet. In some embodiments, the rotatable housing includes a generally cylindrical housing operable to rotate about a longitudinal axis of the rotatable housing. The filter and pump may be positioned within or outside of the rotatable housing. The rotatable housing may be coupled to a power source and a supporting cable via a rotatable joint, such as a swivel joint, and including a slip ring. 
     In some embodiments, each nozzle of the downhole cleanout tool has a nozzle outlet that is oriented at an angle (α) from a radial axis extending from the longitudinal axis of the rotatable housing to a location where the nozzle outlet intersects the periphery of the rotatable housing. This orientation allows for spray from the nozzle to induce a rotational force on the housing to induce rotation so that, as the housing rotates, nozzle spray impinges about the full internal circumference of a cross-section of a wellbore in which the nozzle is placed. In some embodiments, the rotation of the housing may be independently driven by an on-board motor. 
     In some embodiments, the filter of the tool is a canister filter having a filter inlet fluidly coupled to the fluid inlet, a generally cylindrical body forming a cylindrical cavity, and a plurality of apertures disposed about the circumference of the cylindrical body. The apertures are fluidly coupled to an annulus between an external surface of the canister filter and an internal surface of the rotatable housing. The annulus may be fluidly coupled to the pump inlet to allow for fluid to be drawn through the filter toward the pump inlet upon operation of the pump. 
     In some embodiments, the rotatable housing is coupled to a downhole end of the filter, and the rotatable housing is coupled to a spindle extending from the rotatable housing through the cylindrical cavity of the filter. In such embodiments, the spindle may comprise an auger. The spindle and auger may be operable to rotate relative to the generally cylindrical body of the filter when fluid is circulated through the nozzle, thereby allowing the auger to consolidate particulate gathered in the filter at a first end of the filter cavity. In some embodiments, cleaning of the wellbore may be accomplished solely by the nozzle spray that is impinged upon the wellbore wall. In other embodiments, cleaning may be augmented by scrubbers or brushes that extend from an external surface of the rotatable housing. 
     Turning now to the figures,  FIG. 1A  shows a wireline or slickline cleanout system  100  that includes a wireline or slickline-deployed cleanout tool  150  deployed to remove scaling in a wellbore  112  that extends into a subterranean formation  120 . The wellbore may have a casing  116 , as shown in  FIG. 1A . In  FIG. 1A , a platform  104  supports a derrick  102  having a pulley  106  for raising and lowering the cleanout tool  150  that is lowered through the wellhead by a wireline or slickline cable  110 . The cable  110  is deployed from a spool  108  of cable  110  that may be coupled to a control system (not shown). The cable  110  may be routed over a pulley  106  and into the wellbore  112 . Once deployed into the wellbore  112 , a well operator may directly or indirectly operate the cleanout tool  150  to remove scaling from the interior surface of the casing  116 .  FIG. 1B  is analogous to  FIG. 1A  and shows the cleanout tool  150  deployed from a sea-based platform  132 . Like components shown in  FIG. 1B  have the same reference numerals as used with regard to  FIG. 1A  and may not be further discussed. In  FIG. 1B , the wellbore  112  extends beneath a blowout preventer  136  and seabed  140  into the subterranean formation  120 . 
       FIG. 2  shows an embodiment of a cleanout tool that is analogous to the cleanout tool  150  of  FIGS. 1A and 1B , deployed within a wellbore  112  by cable  110 . The tool includes a tool housing  200  having a non-rotating portion  202 , which may include a control unit that communicates with a control system at the surface and provides power and telemetry capabilities to the cleanout tool. The non-rotating portion  202  may be coupled to a rotatable joint  204 , which may include, for example, a swivel joint and a slip ring for providing electrical and control signals to, and receiving signals from, the lower portion of the tool. 
     The rotatable joint  204  couples the non-rotating portion  202  of the tool housing  200  with a lower rotating portion  242 , which may also be referred to as a rotatable housing. The lower rotating portion  242  may include a motor and pump unit  206 , which includes a motor, pump, and one or more nozzles  208 , as shown in  FIG. 2A . In some embodiments, lower rotating portion  242  includes a generally cylindrical housing operable to rotate about a longitudinal axis  236  of the tool housing  200 . The lower rotating portion  242  may also include a filter housing  210  for housing a filter  214 . In some embodiments, the filter  214  of the tool is a canister filter having a generally cylindrical body forming a cylindrical cavity  232 , and a plurality of apertures disposed about the circumference of the cylindrical body. In other embodiments, the filter  214  is a filter stack. 
     The filter housing  210  includes a fluid inlet  212  for receiving fluid from the wellbore  112 . The fluid inlet  212  is fluidly coupled to a filter cavity  232 . The filter  214  includes a filter media that separates the filter cavity from a filter annulus  216  that is bounded by the external surface of the filter  214  and the filter housing  210 . The filter  214  may include a plurality of apertures, or a porous surface that separates the filter cavity  232  from the filter annulus  216  and prevents particulates from flowing from the filter cavity  232  through the filter  214  to the annulus  216 . 
     In some embodiments, the annulus  216  forms a portion of a fluid flow path that is fluidly coupled to a pump inlet  218  and pump outlet  220 . In such embodiments, the pump is operable to draw fluid from the wellbore  112  through the fluid inlet  212  into the filter cavity  232 , across the filter  214 , into the filter annulus  216 , into the pump inlet  218 , and out of the pump outlet  220  through nozzles  208  that are fluidly coupled to the pump outlet  220 . 
     In some embodiments, each nozzle  208  of the downhole cleanout tool has a nozzle outlet  238  that is oriented at an angle (α) from a radial axis  240  extending from the longitudinal axis  236  of the rotatable housing to a location where the nozzle outlet intersects the periphery of the rotatable housing. This orientation allows for spray from the nozzle to induce a rotational force on the lower rotating portion  242  to induce rotation so that as the housing rotates, nozzle spray impinges about the full internal circumference of a cross-section of a wellbore  112  in which the nozzle  208  is placed. 
       FIGS. 3 and 4  show alternative embodiments of cleaning tools that include many components that are similar to those of  FIG. 2 . In the embodiment of  FIG. 3 , the tool again includes a tool housing  300  having a non-rotating portion  302 , which may include a control unit that provides power and telemetry capabilities to the tool. The non-rotating portion  302  may be coupled to a rotatable joint  304 , which may include a slip ring for providing electrical and control signals to, and receiving signals from, the lower portion of the tool housing  300 . The rotatable joint  304  couples the non-rotating portion  302  of the tool housing  300  with a lower rotating portion  342 , or rotatable housing. The lower rotating portion  342  may include a motor and pump unit  306 , which includes a motor, pump, and one or more nozzles (analogous to nozzles  208  shown in  FIG. 2A ). In some embodiments, lower rotating portion  342  includes a generally cylindrical housing operable to rotate about a longitudinal axis  336  of the tool housing  300 . The lower rotating portion  342  may also include a filter housing  310  for housing a filter  314 . 
     In some embodiments, each nozzle of the downhole cleanout tool has a nozzle outlet that is oriented at an angle (α) from a radial axis extending from the longitudinal axis of the rotatable housing to a location where the nozzle outlet intersects the periphery of the rotatable housing (analogous to the orientation of  FIG. 2A ). This orientation allows for spray from the nozzle to induce a rotational force on the lower rotating portion  342  so that as the housing rotates, nozzle spray impinges about the full internal circumference of a cross-section of a wellbore  112  in which the nozzle is placed. In the embodiment of  FIG. 3 , scrubbers  322 , which may be metallic scrubbers, brushes, or bristles, are affixed to the external surface of the rotatable housing and extend to engage the internal wall of the wellbore  112 . As noted above, in some embodiments, rotation of the rotating portion  342  may be assisted or independently driven by a motor included in the tool (in, for example, the motor and pump unit  306 ). 
     In the embodiment of  FIG. 4  a cleanout tool that is analogous to the cleanout tool  150  of  FIGS. 1A and 1B  is again deployed within a wellbore  112  by cable  110 . The tool has a tool housing  400  that includes a non-rotating portion  402  coupled a lower rotating portion  442 . The nonrotating portion includes a control unit  403  that provides power and telemetry capabilities to the tool. The non-rotating portion  402  may be coupled to a rotatable joint  404  that is also coupled to the lower rotating portion  442 . In the embodiment of  FIG. 4 , the nonrotating portion  402  also includes a filter  414  positioned above or uphole from lower rotating portion  442 . 
     The lower rotating portion  442  again includes a motor and pump unit  406 , which includes a motor, pump, and one or more nozzles (as shown in  FIG. 2A ). The lower rotating portion  442  includes a generally cylindrical housing operable to rotate about a longitudinal axis  436  of the tool housing  400 . 
     Here, the filter  414  of the tool is a canister filter having a generally cylindrical body forming a cylindrical cavity  432 , and a plurality of apertures disposed about the circumference of the cylindrical body. A spindle  426  and auger  424  are positioned within the cylindrical cavity  432  and rotatably coupled to the lower rotating portion  442  such that rotation of the lower rotating portion  442  results in corresponding rotation of the auger  424  and spindle  426 . In some embodiments, the spindle  426  conveys wiring from the control unit positioned in the non-rotating portion  402  to the motor and pump unit  406 . 
     The filter housing  410  again includes a fluid inlet  412  for receiving fluid from the wellbore  112 . The fluid inlet  412  is fluidly coupled to a filter cavity  432 . The filter  414  includes a filter media that separates the filter cavity from a filter annulus  416  that is bounded by the external surface of the filter  414  and the filter housing  410 . The filter  414  may include a plurality of apertures, or a porous surface that separates the filter cavity  432  from the filter annulus  416  and prevents particulates from flowing from the filter cavity  432  through the filter  414  to the annulus  416 . 
     The annulus  416  forms a portion of a fluid flow path that is fluidly coupled to a pump inlet  418  and pump outlet  420 . In such embodiments, the pump is operable to draw fluid from the wellbore  112  through the fluid inlet  412  into the filter cavity  432 , across the filter  414 , into the filter annulus  416 , into the pump inlet  418 , and out of the pump outlet  420  through nozzles  408  that are fluidly coupled to the pump outlet  420 . 
     As described above with respect to the embodiments of  FIGS. 2 and 3 , each nozzle of the downhole cleanout tool has a nozzle outlet that is oriented at an angle (α) from a radial axis extending from the longitudinal axis  436  of the rotatable housing to a location where the nozzle outlet intersects the periphery of the rotatable housing. This orientation allows for spray from the nozzle to induce a rotational force on the lower rotating portion  442  to induce rotation so that as the housing rotates, nozzle spray impinges about the full internal circumference of a cross-section of a wellbore  112  in which the nozzle is placed. In the embodiment of  FIG. 4 , the coupling between the lower rotating portion  442  and spindle  426  and auger  424  allows for spray from the nozzles to also result in rotation of the auger  424 . The auger  424  is operable, when rotated, to collect and compress particulate  438  filtered from fluid in the cylindrical filter cavity  432  at a downhole end of the filter cavity  432 . 
     In operation, the embodiments of wellbore cleanout tools described with regard to  FIGS. 2-4  function to clean it wellbore according to the principles described below. Referring again to  FIGS. 2 and 2A , the cleanout tool is actuated automatically or via a control signal received over cable  110 . The control signal results and actuations signal to the motor and pump unit  206  to initiate the pump. Initiation of the pump results in wellbore fluid being drawn into the tool housing  200  through the fluid inlet  212  and ultimately into the pump inlet  218 . Fluid drawn in by the pump is expelled from the pump outlet  220  and forced through the nozzles  208 . The nozzles  208  include nozzle outlets that are directed at the wellbore wall at an angle (α) from the radial. The angle (α) may be forty-five degrees, and may range from thirty to sixty degrees. Other angles may also be suitable. The fluid stream results in a tangential force that causes rotation of the rotating portion  242  of the tool housing  200 . As the rotating portion  242  of the tool housing  200  rotates, fluid from the nozzles contacts the full circumference (360°) of the well surface. 
     The pump flow rate and nozzles  208  are selected such that the nozzle spray is operable to clean the wall of the wellbore  112  by directing a high velocity stream or jet of fluid against the wellbore wall to remove scaling and other debris. In an embodiment, the flow rate and nozzles are configured to direct turbulent flow onto the wellbore wall. When the pressurized fluid impinges on the wall of the wellbore  112 , kinetic energy of the fluid knocks debris and other build-up off of the wellbore wall. The number of nozzles may be selected based on the well fluid composition and desired rotational speed of the rotating portion  242 . Debris may be collected by the tool as it continues to operate. 
     The pump flow rate and nozzles  208  are selected such that the nozzle spray is operable to clean the wall of the wellbore  112  by directing a high velocity stream or jet of fluid against the wellbore wall to remove scaling and other debris. Debris may be collected by the tool as it continues to operate. Fluid proximate to the tool housing  200  is drawn into the fluid inlet  212  where it is filtered to remove debris. The filter debris is collected within the cavity  232  as fluid is drawn from the fluid inlet  212  through the filter  214  and into the filter annulus  216 . The filtered fluid is then circulated through the pump and emitted at a high velocity through the nozzles  208  to continue to remove scaling and debris from the wellbore wall. This fluid circulation over a period of time leads to a cleaner well and the debris that is accumulated in the filter  214  can be transported back to the surface for disposal. 
     The embodiment of  FIG. 3  functions similarly to that of  FIG. 2 . Actuation of the pump unit  306  results in fluid flow through the nozzles positioned in the rotating portion  342 . Nozzles in the rotating portion  342  operate to spray fluid onto the wellbore wall to remove scaling and other debris. The cleaning effected by the nozzles is, however, augmented by scrubbers  322  that contact the wellbore wall when the rotating portion  342  is rotated, thereby mechanically removing scale and other debris from the wellbore wall so that it may be collected by the filter  314 . 
     Operation of the embodiment of  FIG. 4  is similar, though certain components of the cleaning tool are oriented differently. Here, the filter  414  is positioned within the non-rotating portion  402  of the tool housing  400 . The motor and pump unit  406  and associated nozzles, however, are positioned within the rotating portion  442 , which is coupled to the filter housing  410 . The rotating portion  442  is further coupled to a spindle  426  and auger  424  that are free to rotate within the cylindrical cavity  432 . Actuation of the pump unit  406  and nozzles again results in removal of scaling and other debris from the wellbore. The debris may be collected in the filter and compressed toward an end of the filter  414  to allow prolonged operation of the cleaning tool. In some embodiments, the spindle  426  and auger  424  are coupled to the motor and pump unit  406  and are directly driven by the motor and pump unit  406 . In other embodiments, the spindle  426  and auger  424  may be driven by the fluid forces generated by fluid being pulled through the filter by the motor and pump unit  406 . In some embodiments, the filter  414  rotates and the spindle  426  and auger  424  remain stationary or rotate in an opposite direction. This relative rotation between the filter  414  and the spindle  426  and auger  424  helps to move the debris further into the cylindrical cavity  432  by the auger  424 . 
     The auger  424  may have a softer material tip (e.g., a non-metal tip affixed to a metallic auger  424 ) around the area touching the filter to effectively wipe the interior surface of the filter  414  without causing damage. In this manner, rotation of auger  424  with respect to filter  414  helps to clean or wipe the interior surface of the filter  414  to diminish the occurrence damage and obstructions. 
     The above-disclosed embodiments have been presented for purposes of illustration and to enable one of ordinary skill in the art to practice the disclosure, but the disclosure is not intended to be exhaustive or limited to the forms disclosed. Many insubstantial modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The scope of the claims is intended to broadly cover the disclosed embodiments and any such modification. 
     As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise” and/or “comprising,” when used in this specification and/or the claims, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. In addition, the steps and components described in the above embodiments and figures are merely illustrative and do not imply that any particular step or component is a requirement of a claimed embodiment. 
     The present disclosure may also be understood as including at least the following clauses: 
     Clause 1: A downhole cleanout tool comprising: a tool housing having a fluid inlet and a fluid outlet; a filter disposed between the fluid inlet and the fluid outlet; a pump having a pump inlet and a pump outlet, the pump being fluidly coupled to at least the fluid inlet to motivate fluid across the filter; and a rotatable housing having at least one nozzle disposed therein, the nozzle being fluidly coupled to the pump outlet. 
     Clause 2: The downhole cleanout tool of clause 1, wherein the rotatable housing comprises a generally cylindrical housing operable to rotate about a longitudinal axis of the rotatable housing, wherein the filter and pump are disposed within the rotatable housing, and wherein the rotatable housing is coupled to a power source and a supporting cable via a rotatable joint. 
     Clause 3: The downhole cleanout tool of clause 2, wherein each nozzle comprises a nozzle outlet oriented at an angle (α) from a radial axis extending from the longitudinal axis of the rotatable housing to a location where the nozzle outlet intersects the periphery of the rotatable housing. 
     Clause 4: The downhole cleanout tool of clause 2 or 3, further comprising: a cable, wherein the rotatable joint comprises a slip ring and wherein, the rotatable housing is configured to rotate about the longitudinal axis upon circulation of fluid through the nozzle. 
     Clause 5: The downhole cleanout tool of any of clauses 1-4, wherein the filter is a canister filter having: a filter inlet fluidly coupled to the fluid inlet, a generally cylindrical body forming a cylindrical cavity, and a plurality of apertures disposed about the circumference of the cylindrical body, the apertures being fluidly coupled to an annulus between an external surface of the canister filter and an internal surface of the rotatable housing, wherein the annulus is fluidly coupled to the pump inlet. 
     Clause 6: The downhole cleanout tool of clause 5, wherein the rotatable housing is coupled to a downhole end of the filter, and wherein the rotatable housing is coupled to a spindle extending from the rotatable housing through the cylindrical cavity of the filter, the spindle comprising an auger. 
     Clause 7: The downhole cleanout tool of clause 6, wherein the spindle and auger are operable to rotate relative to the generally cylindrical body of the filter when fluid is circulated through the nozzle. 
     Clause 8: The downhole cleanout tool of any of clauses 1-7, wherein the rotatable housing comprises a plurality of brushes extending from an external surface of the rotatable housing. 
     Clause 9: A method of cleaning a wellbore comprising: deploying cleanout tool into a well, the cleanout tool comprising a tool housing having a fluid inlet and a fluid outlet, a filter disposed between the fluid inlet and the fluid outlet, a pump having a pump inlet and a pump outlet, the pump being fluidly coupled to at least the fluid inlet, and a rotatable housing having at least one nozzle disposed therein, the nozzle being fluidly coupled to the pump outlet; and operating the pump to motivate fluid across the filter and through the nozzle, wherein operating the pump causes rotation of the rotatable housing and application of a scrubbing stream of fluid from the nozzle to an inner circumferential surface of the wellbore. 
     Clause 10: The method of clause 9, wherein operating the pump comprises delivering power and an actuation signal to the pump via a supporting cable and a rotatable joint, and wherein the filter and pump are disposed within the rotatable housing, the rotatable housing being coupled to the supporting cable by the rotatable joint. 
     Clause 11: The method of clause 9 or 10, further comprising orienting each nozzle at an angle (α) from a radial axis extending from a longitudinal axis of the rotatable housing to a location where the centerline of a nozzle outlet intersects the periphery of the rotatable housing. 
     Clause 12: The method of clause 11, further comprising dynamically changing the angle (α) upon in response to detecting scaling on the wellbore. 
     Clause 13: The method of any of clauses 9-12, wherein operating the pump comprises motivating fluid through a filter inlet fluidly coupled to the fluid inlet and through a plurality of apertures disposed about a circumference of filter. 
     Clause 14: The method of clause 13, further comprising rotating an auger disposed on a spindle positioned within a cylindrical cavity of the filter in response to rotation of the rotatable housing. 
     Clause 15: The method of any of clauses 9-14, further comprising scrubbing the wellbore with a plurality of brushes extending from an external surface of the rotatable housing. 
     Clause 16: A wellbore cleaning system comprising: a cable; and a cleanout tool coupled to the cable, the cleanout tool having a control unit coupled to the cable, a rotatable joint, a pump, a filter, a rotatable housing, and a plurality of nozzles having nozzle outlets spaced equidistantly a periphery of the cleanout tool, wherein the plurality of nozzles are positioned within the rotatable housing. 
     Clause 17: The system of clause 16, wherein: the rotatable housing comprises a generally cylindrical housing operable to rotate about a longitudinal axis of the rotatable housing, the filter and pump are disposed within the rotatable housing, and the rotatable housing is electrically coupled to the control unit through the rotatable joint. 
     Clause 18: The system of clause 16 or 17, wherein each nozzle comprises a nozzle outlet oriented at an angle (α) from a radial axis extending from a longitudinal axis of the rotatable housing to a location where the nozzle outlet intersects the periphery of the rotatable housing. 
     Clause 19: The system of clause 18, wherein the rotatable housing comprises a plurality of brushes extending from an external surface of the rotatable housing. 
     Clause 20: The system of any of clauses 16-19, further comprising an auger and spindle positioned within a cylindrical cavity of the filter and rotationally coupled to the rotatable housing, wherein the auger and spindle are operable to rotate within the filter upon rotation of the rotatable housing.