Abstract:
A downhole tool with a feedback arrangement including a tool having one or more fluid outflow ports that exhaust fluid during normal operation of the tool. A feedback arrangement in operable communication with the fluid exhausted from the one or more fluid outflow ports during operation of the tool. The feedback arrangement interacting with exhausting fluid to produce a signal receivable at a remote location indicative of proper tool operation. A method for confirming operation of a downhole tool is included.

Description:
BACKGROUND 
     In drilling and completion industries such as hydrocarbon exploration and production, Carbon Dioxide sequestration, etc., tools are often run into the downhole environment for particular purposes requiring locating the tool at a target position. Traditionally an operator will keep track of a length of tubing in the hole and anticipate the specific tool at issue locating upon a feature within the hole. The feature may be a seat, profile, bottom, etc. Such “gauging” of where the tool is occurs in trips into the borehole, trips out of the borehole and movements of the tool in defined areas of the borehole. 
     For example, an operation in a borehole may require several actions taking place between a downhole most location and an uphole most location for the particular operation. Providing profiles at these locations will provide a guide to the operator to keep the target tool in the target location for the job being done. 
     While such measures are currently used, tools do not always engage profile properly and effective indication of position at the surface may not be received. Such situations result in lost time, which translates to cost increases. 
     In order to address the foregoing, a downhole position locating device with fluid metering feature (U.S. Pat. No. 7,284,606, the entirety of which is incorporated herein by reference) was developed. Such a tool or others that function by providing a fluid movement component of their operation, which fluid component has an effect on tool operation such as in the &#39;606 patent wherein the fluid delays an action until the fluid is removed by exhaustion or by movement to another chamber are useful as landing in a sought profile is better verifiable by a pull or push from surface that allows for a slower movement of the string. While the concept generally works well, there is a possibility that the tool experiences restricted movement due to friction, Blow Out Preventer (BOP) contact or other impediments rather than due to an engagement with a profile and fluid movement. In such case, the indication of tool location at surface would be inaccurate. Since accuracy in downhole operations improves efficiency and reduces costs, the industry will well receive improved arrangements supporting these goals. 
     SUMMARY 
     A downhole tool with a feedback arrangement including a tool having one or more fluid outflow ports that exhaust fluid during normal operation of the tool; and a feedback arrangement in operable communication with the fluid exhausted from the one or more fluid outflow ports during operation of the tool, the feedback arrangement interacting with exhausting fluid to produce a signal receivable at a remote location indicative of proper tool operation. 
     A method for confirming operation of a downhole tool including disposing an oscillator within a fluid outflow path; actuating the tool thereby causing fluid to flow in the outflow path; affecting the oscillator with the fluid; and creating a signal with the oscillator representative of tool operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
         FIGS. 1A-C  is a representation of one embodiment of a metering tool with feedback arrangement in three distinct positions; 
         FIGS. 2A-C  is a representation of another embodiment of a metering tool with feedback arrangement in three distinct positions; and 
         FIG. 3  is a plan view of an embodiment of a pulser. 
     
    
    
     DETAILED DESCRIPTION 
     It is to be appreciated that while the overall configuration of the metering tool of the &#39;606 patent is utilized to illustrate two embodiments of the disclosed invention, other configurations where fluid movement is a part of the function of the tool will also benefit from the embodiments providing feedback as described herein. 
     Referring to  FIGS. 1A-C , a metering tool  10  is generally depicted with a feedback arrangement including an oscillator  12 . The metering tool  10  is also shown to include an exemplary embodiment where fluid movement is a part of the function of the tool. The illustrated exemplary embodiment includes a mandrel  100  made up of top sub  120 , upper body  140 , lower body  16  and bottom sub  18 . An outer sleeve  200  has a window  22  for each dog  24  that is used. One or more dogs  24  can be used. Dogs  24  have tabs at opposed ends to limit the outward travel of the dogs  24  with respect to window  22 .  FIG. 1A  shows the dog  24  in section. The dog  24  is generally U-shaped having a pair of inwardly oriented legs  28  and  30 . On the trip into the well, surface  32  on dog  24  may encounter an obstacle. On the trip out of the well, surface  34  on dog  24  may encounter an obstacle. Sleeve  200  is mounted to slide over mandrel  10 . It is biased uphole by spring  36  that bears on surface  38  of bottom sub  18 . Spring  40  bears on surface  42  of top sub  120  and applies an opposing force to sleeve  20  than spring  36 . Spring  40  may be weaker than spring  36  for reasons that will be explained below. 
     Upper body  140  has three grooves  44 ,  46 , and  48 . These grooves are deep enough so that when legs  28  and  30  are in them, outer surface  50  of dogs  24  recedes inside of window  22 . In this manner the tool  10  can pass an obstruction going downhole and can be removed after release going uphole. If an obstruction is encountered by surface  32  going in the hole, the spring  40  is compressed as the sleeve  20  and dogs  24  stop downhole motion. Continued downhole movement of the mandrel  100  not only compresses spring  40  but also positions grooves  44  and  46  in alignment with legs  28  and  30  of dogs  24  to allow them to retract to a position closer to the central axis  52  and within sleeve  200 . At that point the obstruction can be passed and spring  40  can bias the sleeve  200  back into the neutral position shown in  FIG. 1A .  FIG. 1B  shows the legs  28  and  30  getting cammed out of grooves  44  and  46  by the action of spring  40  after the obstruction going downhole is cleared. Note that sloping surfaces  52  and  54  facilitate the exit of legs  28  and  30  from grooves  44  and  46  under the return force of the formerly compressed spring  40 . With the obstacle cleared going downhole, the dogs  24  resume the neutral run in position shown in  FIG. 1A . 
     Between the sleeve  200  and mandrel  100  an upper fluid reservoir  56  ( FIG. 1C ) and a lower fluid reservoir  58 . A fill port  60  allows charging the fluid at the surface. Thermal and hydrostatic effects in this closed system of interconnected reservoirs are fully compensated by a piston that can be biased by Belleville washers, for example, or any other device that is comparable. Those skilled in the art will appreciate the benefit of such compensation on the structure of the device especially when it is deployed at great depths and/or high temperature applications.  FIG. 1B  best illustrates other features of this reservoir system. There is a flow restrictor  66  that regulates the flow rate from reservoir  58  into reservoir  56 . There is a check valve  68  that permits a bypass of restrictor  66  when the fluid is flowing in the opposite direction from reservoir  56  to reservoir  58 . A pressure relief device  70  is in line with the restrictor  66  so that when fluid is urged in a direction from reservoir  58  to reservoir  56  there will have to be a rise in the driving pressure to cause such flow to a predetermined level before any flow begins. 
     The fluid system is operative to create a delay as the dogs  24  are in the desired location and a force is applied to the mandrel  100  to create a surface signal for such engagement prior to the release of the dogs  24  from the locating groove (not shown). In the exemplary embodiments further described herein, the feedback arrangement is further provided features to produce an oscillating or pulsating signal that is more easily discernible at a remote location. The system also serves to allow a reduction of the applied pulling force before release to reduce the slingshot effect from release. When used with the optional pressure relief device  70  the tool can be inverted and can be used to apply a load in a predetermined range on a BHA without concern for premature release, such as an offshore drilling application where a heavy compensator system is employed. 
       FIG. 1A  shows the run in position with the dogs  24  having legs  28  and  30  out of any of the grooves  44 ,  46 , and  48 . The dogs may be biased into the  FIG. 1A  position where legs  28  and  30  straddle groove  46  by virtue of spring  36  overpowering spring  40  to move sleeve  200  to the  FIG. 1A  position. As the tool is brought downhole, an obstacle will first hit surface  32  on dogs  24 . The mandrel  100  will continue downhole as the dogs  24  stop the descent of the sleeve  200 . As grooves  44  and  46  come into alignment with legs  28  and  30 , the dogs  24  will be able to retract sufficiently to allow the tool to continue past the obstacle. The dogs  24  can retract within sleeve  200  as much as necessary to allow the obstacle to be cleared. The advancing of the mandrel  100  with the dogs  24  temporarily stuck on an obstacle, compresses spring  40 . After the obstacle is cleared, spring  40  relaxes to return the tool to the  FIG. 1A  position from the  FIG. 1B  position. It should be noted that advancing the mandrel downhole with the dogs  24  stopped by an obstacle will result in sleeve  200  taking dogs  24  against the bias of spring  40  taking the lower end  21  of sleeve  200  away from upper end  23  of sleeve  25 , whose relative movement with respect to the mandrel  100 , at other times, creates movement of fluid between reservoirs  56  and  58 . The amount of this movement to reset the dogs  24  to the  FIG. 1A  position after clearing the obstacle is also quite short. 
     When the desired depth is reached, the tool is pulled up until the surface  34  engages a desired locating groove downhole. At that point, further upward pulling on the mandrel  10  from the work string (not shown) will force fluid from reservoir  58  to reservoir  56  through restrictor  66 . This regulates the rate of movement of mandrel  100  as the force is being applied to give surface personnel the time to notice a signal that the desired groove has been engaged and a force that well exceeds the potential drag force from friction of slip/stick effects on the work string in a deviated wellbore are applied. The rig crew can then actually lower the applied pulling force before the actual release happens to reduce the slingshot effect from the release. Release occurs after the mandrel  100  moves a sufficient distance to place grooves  46  and  48  in alignment with legs  28  and  30  to allow the dogs  24  to retract and the tool to be returned to the  FIG. 1A  position. This occurs because the pulling uphole with the dogs  24  in the locating groove compresses spring  36  as seen in  FIG. 1C . Retraction of the dogs  24  allows spring  36  to overcome spring  40  and the tool returns to the  FIG. 1A  position, ready for another cycle. With the use of the optional relief device  70  the surface personnel are assured that a pulling force up to a predetermined level will not initiate the release sequence. Hence force can be applied and removed any number of times before there is a release. Those skilled in the art will appreciate that the tool can be used in an inverted orientation and function similarly in one application, for example where a range of weight on a BHA is desired in a given range without fear of initiating a release sequence. In such an application, rather than a pulling force uphole, a pushing force downhole is applied with the dogs  24  engaged in a receptacle. Combining with the use of the optional relief device  70  no fluid flow between reservoirs  56  and  58  can happen until a predetermined force is exceeded. This configuration can be used in offshore drilling in conjunction with heave compensators. 
     The use of the check valve  68  allows the tool to quickly find its neutral position after a release so that the test can be quickly repeated, if desired. The use of the restrictor  66  allows more time at the surface to hold a force before release and further allows lowering the applied force after the passage of time but before release to reduce the slingshot effect from release. The pressure relief device  70  allows application of force for any desired time without fear of release if the force is kept at a level where the relief device remains closed. The fluid used on the reservoirs can be a liquid or gas. The compensator is an optional feature. The tool is serviceable in the well in opposed orientations depending on the intended service. Although four dogs  24  are illustrated one or more such dogs can be used. Biasing of springs  26  and  40  can be accomplished by equivalent devices. 
     In the embodiment of  FIGS. 1A-1C , the feedback arrangement is an oscillator  12  illustrated as a spring mass that is positioned within a fluid outflow through outflow port(s)  14  caused by metering of the metering tool  10 . It is to be understood that although a spring mass is illustrated as oscillator  12 , any mass that can be caused to oscillate due to fluid flow can be used. As will be appreciated from a review of the metering tool in the incorporated by reference &#39;606 patent, fluid is exhausted from chamber  56  to chamber  58 , or from chamber  58  to chamber  56 , during the normal operation of the tool  10 , such as when a dog  24  engages a desired locating groove downhole. Because of the placement of the oscillator  12  within reservoir  58 , the fluid flow through outflow port(s)  14  interacts with the oscillator  12  to cause the oscillator  12  to oscillate. Oscillation of the oscillator  12  produces a signal that can be received at remote locations and is indicative of proper tool operation, such as when the dog  24  engages a desired locating groove downhole. Different forms of oscillation can be transmitted to remote locations for reliable feedback of the operation of the tool. In this case, the spring mass, which may be a coil spring as shown, oscillates against the tool itself creating vibration that is transmitted through a string  16  supporting the tool back to surface or other remote location. The vibration is detectable at the remote location by hand or sensor or auditorily and confirms proper operation of the tool in the downhole environment. 
     In another embodiment, referring to  FIGS. 2A-C , a metering tool  10  with a feedback arrangement includes a pulser  20  mounted proximate a fluid outflow through the outflow port(s)  14  of the tool  10 . Upon fluid outflow, the pulser arrangement will rotate. The pulser, in one embodiment is hence a rotating member. Rotation of the pulser is due to one or more (four shown) openings  22  in the pulser  20  that are configured angularly relative to an axis of the rotatable pulser. Rotation of the pulser  20  results in an alternating pattern of openings and solid sections of the pulser aligning with the fluid outflow of the tool  10 . This alternatingly allows fluid passage and fluid blockage (or at least inhibition). Accordingly, pressure within the fluid downstream of the pulser changes alternatingly at the same rate that the pulser rotates. Pressure downstream of the pulser decreases when fluid flow is inhibited and returns to system pressure with each alignment of the openings  22 . More particularly, when one of the openings (or more of them if there are more fluid outflow ports or if the pulser is configured to align more than one of the openings with the fluid outflow (in the event that the fluid outflow is broader in area than one of the openings  22  plus an adjacent solid portion of the pulser  20 ) is aligned with the fluid outflow, the pressure downstream of the pulser is the same as it is upstream of the pulser. When the pulser rotates to a position where the fluid flow from the outflow port(s) is blocked or inhibited, the pressure in the fluid downstream of the pulser dips. The dip in pressure and subsequent recovery of system pressure can be received and in some cases might actually be measured a substantial distance from the pulser  20  and tool  10 . The pressure change is embodied as an acoustic signal propagating through fluid in the borehole and provides feedback at a remote location or at the surface of fluid outflow from the outflow port(s). Depending upon the length of time a particular tool has a fluid outflow, the acoustic signal may have time to reach a remote location such as the surface to be perceived or the signal may act as a post actuation confirmatory signal. This is because an appreciable amount time is required for signal propagation in a fluid medium. And while clearly the time factor for signal propagation in a fluid medium is directly related to the density of that fluid, (and of course distance is a factor in overall travel time) in virtually all cases of fluid borne acoustic signals from downhole tools, it will be likely that the actuation time causing the fluid outflow will be less than the transit time for the signal hence making such signals confirmatory. 
     While the foregoing embodiment provides one method for propagating a signal based upon the structure shown, there is another that provides for much less of a time delay. This utilizes the actual work string the tool is disposed in to propagate a vibratory signal. Because the pulser, in addition to what it does as noted above, will also cause pressure variations in the tool that is exhausting fluid, the string itself experiences varying strain that is cyclic. A cyclic change in tensile strain can function as a signal. More specifically, and using the metering tool of the &#39;606 patent as an example, as the tool contacts a locating profile, applied tension displaces fluid through the outflow ports and past the pulser. The flow of fluid rotates the pulser thereby restricting and unrestricting the flow of liquid through the ports. This variance in restriction results in a variance of the pressure within the tool chamber. The variance in chamber pressure in the tool will be manifested as a variance in force between the metering tool and the profile. This force variation is detectable as a variance in tensile force in the workstring upon which the tool has been run and operated. The signal provides increased confidence that the tool  10  is operating properly. One benefit of this embodiment is the speed at which a signal will propagate through metal as opposed to a fluid. In view of this speed increase, the signal is received virtually contemporaneously with the tool actuation. 
     While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.