Abstract:
Acoustic telemetry installation in subterranean wells. In a described embodiment, a method of contacting an assembly with a generally tubular string in a subterranean well includes the steps of: suspending the tubular string in the well, the tubular string extending into a surface structure; and then displacing the assembly through the structure into contact with an exterior of the tubular string. The assembly can selectively contact any one of several tubular strings or other objects within a wellhead or casing. The assembly can be permanently or temporarily used on the well.

Description:
BACKGROUND  
       [0001]     The present invention relates generally to operations performed and equipment utilized in conjunction with a subterranean well (whether on land, underwater or offshore) and, in an embodiment described herein, more particularly provides an acoustic telemetry installation system.  
         [0002]     It is normal practice to secure an acoustic telemetry transceiver to a tubular string at the surface by clamping the transceiver to the tubular string above a rotary table where the tubular string is suspended. This method is used, for example, in the ATS™ acoustic telemetry system marketed by Halliburton Energy Services of Houston, Tex.  
         [0003]     Another acoustic telemetry transceiver is interconnected in the tubular string downhole. The downhole transceiver receives indications from downhole sensors and transmits these indications acoustically via the tubular string to the surface transceiver. The surface transceiver can also acoustically transmit signals (such as command and control signals) to the downhole transceiver.  
         [0004]     Unfortunately, placement of the surface transceiver above the rotary table (where the tubular string is suspended) leads to attenuation of the acoustic signal from the downhole transceiver. In addition, surface equipment (e.g., pumps, compressors and other equipment at the surface) introduces background noise, which is difficult to filter from the attenuated acoustic signal.  
         [0005]     In another method, an acoustic telemetry sensor (such as an accelerometer) is clamped to a tubular string prior to installing a wellhead on a well. The sensor is positioned below the wellhead when the wellhead is installed. However, this method requires the wellhead to be removed for repair or replacement of the sensor, and requires that wires or other lines for the sensor pass through the wellhead and/or seals at the time the wellhead is installed.  
         [0006]     In yet another method, an acoustic telemetry sensor is lowered on wireline through the tubular string to a position downhole, and then anchored to the interior of the tubular string. However, this method blocks flow and access through the tubular string, requires that the wireline be present in the tubular string, and requires that access be provided at the surface for the wireline and sensor to enter the interior of the tubular string.  
         [0007]     It will be readily appreciated that improvements are needed in the art of installing sensors and acoustic telemetry devices in wells. It is an object of the present invention to provide such improvements. Principles of the invention will also find use in other applications to achieve other objects.  
       SUMMARY  
       [0008]     In carrying out the principles of the present invention, in accordance with one of multiple embodiments described below, a method of connecting and/or contacting an acoustic telemetry device to a tubular string is provided which solves the above problems in the art.  
         [0009]     In one aspect of the invention, a method of attenuating noise in acoustic signals communicated between surface and downhole locations of a well is provided. The method includes the steps of: attaching an acoustic telemetry device to a generally tubular string; installing the tubular string in the well so that the acoustic telemetry device is positioned at the downhole location; and then displacing another acoustic telemetry device into contact with an exterior of the tubular string.  
         [0010]     In a further aspect of the invention, a portable installation system for use with a subterranean well includes a tubular string installed in the well and extending into a surface structure. A sensor assembly is displaced through the structure into contact with an exterior of the tubular string. The system may be used with wells currently in service, wells in production, and new wells.  
         [0011]     In another aspect of the invention, an installation system for use with a subterranean well includes a tubular string installed either permanently or temporarily in the well and extending into a surface structure, with the tubular string being suspended from a hanger positioned above a portion of the structure. An assembly is displaced through the structure portion into contact with an exterior of the tubular string.  
         [0012]     In yet another aspect of the invention a method of contacting an assembly with a tubular string in a subterranean well is provided. The method includes the steps of: suspending the tubular string in the well, the tubular string extending into a surface structure; and then displacing the assembly through the structure into contact with an exterior of the tubular string.  
         [0013]     In a further aspect of the invention, an installation system for use with a subterranean well includes a tubular string installed in the well and suspended at a first location. An acoustic telemetry device is attached to the tubular string at a second location. Another acoustic telemetry device is displaced into contact with an exterior of the tubular string at a third location between the first and second locations after the tubular string is suspended at the first location.  
         [0014]     These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description below of representative embodiments of the invention and the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a schematic partially cross-sectional view of an acoustic telemetry installation system embodying principles of the present invention;  
         [0016]      FIG. 2  is an enlarged scale schematic cross-sectional view through the system of  FIG. 1 ;  
         [0017]      FIG. 3  another enlarged scale schematic cross-sectional view through the system of  FIG. 1 , depicting an alternate configuration; and  
         [0018]      FIG. 4  is another enlarged scale schematic cross-sectional view through the system of  FIG. 1 , depicting additional details of an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0019]     Representatively illustrated in  FIG. 1  is an installation system  10  which embodies principles of the present invention. In the following description of the system  10  and other apparatus and methods described herein, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present invention. The embodiments are described merely as examples of useful applications of the principles of the invention, which is not limited to any specific details of these embodiments.  
         [0020]     As depicted in  FIG. 1 , a generally tubular string  12  (such as a production tubing string, drill string or coiled tubing string) has been installed in casing  14  lining a wellbore  16 . The tubular string  12  could be of any geometric shape which encloses a gas or fluid, and may be capable of withstanding a pressure differential across the enclosure. The tubular string  12  could be any geometric shape which can support a compressive or tensile load. An exterior of the tubular string  12  can have a cylindrical or noncylindrical shape.  
         [0021]     Interconnected in the tubular string  12  is an acoustic telemetry device  18  (such as an acoustic transceiver) which may be connected to sensors  136  downhole. For example, the device  18  could include one or more sensors  136  (e.g., annulus and/or tubing pressure, temperature, acoustic, etc. sensors), and indications from these sensors may be transmitted some distance to the surface via acoustic signals transmitted through the tubular string  12 .  
         [0022]     It is not necessary for any data or indications provided by the sensor(s)  136  in or connected to the telemetry device  18  to be transmitted immediately. Instead, the data or indications could be stored and then transmitted at a later time. One or more repeaters (not shown) may be used in the tubular string  18  to relay acoustic telemetry signals to and from the telemetry device  18 .  
         [0023]     It is not necessary in keeping with the principles of the invention for the telemetry device  18  to be interconnected as part of the tubular string  12 . The telemetry device  18  could alternatively be positioned internal or external to the tubular string  12 , for example, by incorporating the telemetry device in a packer or bridge plug set in the tubular string.  
         [0024]     At the surface, the tubular string  12  is received in surface structures  20 ,  22 . Each of the structures  20 ,  22  is generally tubular in shape, with the tubular string  12  extending generally coaxially therein. The structures  20 ,  22  are not necessarily cylindrical and can have other shapes, including but not limited to oval, elliptical, polygonal sided, etc.  
         [0025]     The structure  20  includes a wellhead  24  with various valves, spools, flanges, pipes, etc. The wellhead  24  could instead be a BOP (blowout preventer) assembly, for example, if the tubular string  12  is coiled tubing. The structure  22  includes a portion  26  of the casing  14  which extends above a surface  28  of the earth.  
         [0026]     The tubular string  12  is suspended in the wellbore  16  by means of a tubing hanger  30  in the wellhead  24 . In one important aspect of the system  10 , an assembly  40  (such as including an acoustic telemetry device or sensor, not visible in  FIG. 1 , see  FIGS. 2-4 ) is brought into contact with an exterior of the tubular string  12  below the hanger  30  through a sidewall of the wellhead  24 , or through a sidewall of the casing portion  26 , after the wellhead is installed.  
         [0027]     The assembly  40  can be displaced through a sealed or unsealed sidewall of the wellhead  24  via a pipe  32  and valve  34  in communication with an interior of the wellhead. The assembly  40  can be displaced through a sealed or unsealed sidewall of the casing portion  26  via another pipe  36  and valve  38  in communication with an interior of the casing  14 .  
         [0028]     If such pipes  32 ,  36  and valves  34 ,  38  do not exist beforehand on the wellhead  24  or casing portion  26 , they can be added, for example, by a process known to those skilled in the art as “line-tapping.” Thus, the system  10  can be used with existing wells that may not have been completed with provisions for displacing the assembly  40  through the sidewall of the wellhead  24  or casing portion  26 .  
         [0029]     Some benefits of this method of installation are that the assembly  40  contacts the tubular string  12  longitudinally between the hanger  30  and the telemetry device  18 , any lines or wires extending to the assembly are conveniently installed after installation of the wellhead  24 , and the assembly is conveniently accessible for repair, replacement or maintenance. Since the assembly  40  includes an acoustic telemetry sensor, placement of the assembly between the hanger  30  and the telemetry device  18  reduces the attenuation of the acoustic signal detected by the sensor and reduces the background noise transmitted to the sensor (e.g., from surface equipment).  
         [0030]     At this point it should be clearly understood that the system  10  as depicted in  FIG. 1  is merely a single application for the principles of the invention. For example, it is not necessary in keeping with the principles of the invention for a wellhead to be installed on a well, since the tubular string  12  could instead be suspended from a rotary table in a well testing operation, or at another suspension location. It is also not necessary for the assembly  40  to be displaced through a wellhead or a portion of casing, since the assembly could be displaced through another surface structure, such as a riser or a BOP assembly, etc.  
         [0031]     The assembly  40  could include other types of sensors. For example, a pressure sensor could be included in the assembly  40  to monitor annulus pressure. This information would be useful in the process of installing, operating and removing the assembly  40  (e.g., for safety reasons, to aid in evaluating the received acoustic signals, etc.).  
         [0032]     The assembly  40  could include a transmitter, a receiver or a transceiver for acoustic telemetry communication with the downhole telemetry device  18 . The receiver would include the acoustic telemetry sensor, such as one or more accelerometers.  
         [0033]     Referring now to  FIG. 2 , a schematic cross-sectional view of the system  10  is illustrated. The cross-section may be taken laterally through the wellhead  24  at the pipe  32  or the casing portion  26  at the pipe  36 , or any other surface structure through which the assembly  40  is displaced into contact with the tubular string  12 .  
         [0034]     As depicted in  FIG. 2 , the assembly  40  is laterally displaced through a passage  42  in the pipe  32  or  36  into contact with an exterior of the tubular string  12 . The tubular string  12  in this example is centrally located within the wellhead  24  or casing portion  26 .  
         [0035]     The assembly  40  includes a sensor  44  in a tip  46  shaped to complementarily conform to the exterior of the tubular string  12 . The sensor  44  could be one or more of the sensors discussed above, such as an acoustic telemetry sensor, accelerometer or pressure sensor, etc.  
         [0036]     If the tubular string  12  has a cylindrical exterior (e.g., as in production tubing, drill pipe, coiled tubing, etc.), then the tip  46  could have a cylindrical recess therein. If the tubular string  12  has another exterior shape (e.g., hexagonal, square, elliptical, etc.), then the tip  46  could be appropriately shaped to conform to that other shape.  
         [0037]     The sensor  44  could be one or more accelerometers. For example, multiple accelerometers could be aligned with respective longitudinal, radial and tangential axes of the tubular string  12  to detect acoustic signals transmitted along these axes.  
         [0038]     As discussed above, the assembly  40  could include a sensor, a receiver, a transmitter, any combination of these, etc. Thus, the assembly  40  can include any type of acoustic telemetry device  82 .  
         [0039]     Referring additionally to  FIG. 3 , the system  10  is depicted in an alternate configuration in which the tubular string  12  is not centrally or coaxially positioned within the wellhead  24  or casing portion  26 . Instead, the tubular string  12  is off-center in the wellhead  24  or casing portion  26 .  
         [0040]     This may be the situation, for example, in a dual or multiple string completion where at least one other tubular string  48  shares the space within the wellhead  24  or casing portion  26 . In this case, the assembly  40  may be directed at an angle through the passage  42  toward the tubular string  12  (or the tubular string  48 , if desired).  
         [0041]     As with the tubular string  12 , the tubular string  48  is not necessarily cylindrical in shape, but can have any geometric shape. It is also not necessary for any particular structure to be present in the wellhead  24  or casing  26  along with the tubular string  12  in order for the assembly  40  to be directed at an angle through the passage  42 .  
         [0042]     Multiple ones of the assembly  40  may be used at the same time to contact the multiple tubular strings  12 ,  48 . Each of the assemblies  40  would contact a respective one of the tubular strings  12 ,  48 . In this manner, one of the assemblies  40  can be used to communicate with a downhole telemetry device via one of the tubular strings  12 ,  48  while another of the assemblies can be used to communicate with another downhole telemetry device via the other tubular string.  
         [0043]     Referring additionally now to  FIG. 4 , a more detailed cross-sectional view of the system  10  is illustrated. For clarity of description, the casing portion  26  is not illustrated in  FIG. 4 , the assembly  40  being displaced instead through the wellhead  24 , but it should be understood that the assembly  40  can be displaced through a sidewall of the casing portion if desired.  
         [0044]     In this view it may be seen that a biasing device  50  is used to displace the assembly  40  through the passage  42  into contact with the tubular string  12  within the wellhead  24 . The biasing device  50  includes an externally threaded shaft  52  received in an internally threaded and sealed collar  54  attached to a housing assembly  56 .  
         [0045]     By rotating a handwheel  58  on the shaft  52 , the assembly  40  may be gradually displaced under pressure through the passage  42  into contact with the tubular string  12 . In addition, a sufficient biasing force may be applied using the handwheel  58  to maintain the tip  46  of the assembly  40  in contact with the tubular string  12 , even though the tubular string may displace somewhat within the wellhead  24 .  
         [0046]     Lugs  60  engage slots  62  in the housing assembly  56  to prevent the assembly  40  from rotating when the shaft  52  is rotated using the handwheel  58 . Of course, other means of displacing the assembly  40  could be used (such as motors, hydraulic or pneumatic actuators, etc.) in place of, or in addition to, the threaded shaft  52  and collar  54 .  
         [0047]     To provide a more resilient or consistent application of the biasing force to the assembly  40 , the biasing device  50  includes a hydraulic or pneumatic actuator  66 . Pressure is applied via a port  68  to one side of a piston  64  to bias the assembly  40  toward the tubular string  12 .  
         [0048]     By maintaining a consistent pressure on the piston  64 , a consistent biasing force may be maintained against the exterior of the tubular string  12 , whether or not the tubular string displaces somewhat in the wellhead  24 . Thus, the threaded shaft  52  and collar  54  may be used for a “coarse” displacement of the assembly  40 , while the actuator  66  may be used for a final “fine” displacement of the assembly into contact with the tubular string  12  and application of the biasing force.  
         [0049]     If pressure exists in the wellhead  24  (for example, as would be the case at times in fracturing, gravel packing, testing, etc. operations), then this pressure will be applied via the passage  42  to the assembly  40  when the valve  34  is opened to permit the assembly to be displaced therethrough. Alternatively, or in addition, another pressure source (such as a pump truck) could supply backside pressure via valve  76 , e.g., to balance an overpressured tubing during a job.  
         [0050]     The assembly  40  is sealed (for example, by seal  70 ) to prevent this pressure from escaping. Rod wipers  86  are provided to either side of the seal  70 .  
         [0051]     However, this pressure will also bias the assembly  40  to displace away from the tubular string  12  (for example, by applying a biasing force to the assembly, piston  64 , etc.), so that pressure applied to the port  68  of the actuator  66  will need to be increased to counteract this biasing force. In order to reduce or eliminate the increased pressure applied to the actuator  66  to counteract the pressure in the wellhead  24 , the assembly  40  may be partially or completely pressure balanced with respect to pressure in the wellhead. For example, a line (not shown), such as a flexible hose, may be used to transmit pressure from the interior of the wellhead  24  to the interior of the housing assembly  56 .  
         [0052]     Note that other types of biasing means may be used in the biasing device  50  to apply the biasing force to the assembly  40 . For example, compression springs, extension springs, pressurized chambers, etc. could be used in place of, or in addition to, the shaft  52 , collar  54  and actuator  66 .  
         [0053]     In practice, the system  10  would be installed as follows:  
         [0054]     1. The valve  34  would be closed.  
         [0055]     2. Any pipe or other equipment  72  (see  FIG. 1 ) connected to the valve  34  would be depressurized, drained and disconnected.  
         [0056]     3. A tee  74  and valve  76  would be attached to the valve  34 . The pipe or other equipment  72  disconnected from the valve  34  in step 2 would now be connected to the valve  76 . In this manner, the system  10  permits continuation of any previous operations, such as application of pressure or circulation of fluids in the casing  14  via the passage  42 . If no pipe or other equipment  72  needs to be used, then the tee  74  and valve  76  may not be used in the system  10 .  
         [0057]     4. The assembly  40  and biasing device  50  would then be connected via a flange  78  on the housing assembly  56  to the tee  74 . If the tee  74  and valve  76  are not used, then the flange  78  may be connected directly to the valve  34 .  
         [0058]     5. If desired, a pressure balance line would then be connected to apply pressure from the interior of the wellhead  24  to the interior of the housing assembly  56 , as described above.  
         [0059]     6. The valve  34  would then be opened. The valve  76  may also be opened, either before or after the valve  34  is opened, if desired to provide communication with the pipe or other equipment  72 .  
         [0060]     7. The biasing device  50  would then be used to displace the assembly  40  through the valve  34  and passage  42 , until the tip  46  makes contact with the exterior of the tubular string  12 . The handwheel  58  could be used to displace the tip  46  into close proximity to the tubular string  12 , and then the actuator  66  could be used to displace the tip into actual contact with the tubular string and apply the biasing force to maintain such contact.  
         [0061]     The sensor  44  may communicate with surface equipment (such as a control module, recording station, etc.) via wireless telemetry. As an alternative, wires or other lines may extend between the sensor  44  and the surface equipment, in which case the wires or lines may extend through the assembly  40  and exit via the slots  62  in the housing assembly  56  (e.g., through the lugs  60 ).  
         [0062]     Instead of the straight passage  42  depicted in  FIG. 4 , in some cases the passage could be curved, such as when an elbow (e.g., a 45 or 90 degree curve) is used on the wellhead  24  to provide communication with its interior. In those cases, the assembly  40  could include an elongated flexible portion  80 , which would allow the assembly to pass through a curvature in the passage  42 .  
         [0063]     Where the tubular string  12  is not centrally located in the wellhead  24  (e.g., as depicted in  FIG. 3 ), the assembly  40  or its housing assembly  56  may be configured so that the assembly is displaced at an angle, or otherwise off-center. For example, the flange  78  could be angled with respect to the remainder of the housing assembly  56  so that, depending upon how the flange  78  is connected to the tee  74  or valve  34 , the assembly  40  may be directed to the left or to the right as it displaces through the passage  42 .  
         [0064]     Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to these specific embodiments, and such changes are within the scope of the principles of the present invention. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents.