Abstract:
An apparatus and method is disclosed for generating power from the energy of fluid flow in a conduit, such as a pipeline or production tubing of a wellbore. A fan may be comprised of a plurality of blades positioned circumferentially around a central cavity. The blades may be adapted for receiving fluid flow and transmitting energy of fluid flow to rotate the fan. The fan may be configured for generating rotational movement of a magnet relative to an electromagnetic winding to produce electrical energy. The central cavity may be adapted for receiving objects such as wellbore intervention tools or other devices for insertion into the central cavity.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention is directed to a system, apparatus and method for generating power in a conduit, such as in a production tubing of a wellbore or in a pipeline. 
       BACKGROUND OF THE INVENTION 
       [0002]    In modern oil and gas production, it is desirable to position in a wellbore devices that require a source of electrical power. Energy consuming devices may be employed downhole to perform a variety of tasks. For example, sensors may be positioned within a casing for monitoring fluid flow pressure, temperature, and flow rates. Optical or acoustic sensors may be used as well. Other sensing devices can be useful to measure fluid viscosity and density. 
         [0003]    With the advent of reservoir management techniques, sophisticated monitoring and valve systems have been integrated into wellbore casing. This allows portions of a subterranean formation to be open to producing oil/gas upwards in the wellbore, while at the same time other portions of the formation are sealed to avoid production into the wellbore. This may be accomplished by controlling downhole valves. To achieve maximum reservoir performance, it may be necessary to flow from only selected portions of the reservoir at a given time. Subterranean flow monitors and flow control systems may require an external power source. 
         [0004]    Downhole telemetry systems may be powered with a downhole power supply. These systems include a mechanism for generating a seismic signal that travels up the borehole. The resulting signal may be received and collected for additional analysis. Acoustic devices may include transmitters and receivers, such as piezoelectric, electromagnetic acoustic transducers, lasers, signal transmitters, signal receivers and flexural resonators. Also, shaped charges in a perforating gun may employ downhole electrical current as well. Such perforating apparatus may in some instances benefit from the use of an available power source. 
         [0005]    Oil and gas pipelines carry hydrocarbons across vast expanses of remote territory. It is often desirable to have a source of electrical power along the pipeline route. However, pipeline routes may not be near conventional electrical power sources. Such electrical power could be used to illuminate the pipeline area for maintenance or security, transmit wireless signals corresponding to pipeline flow conditions or temperature, or provide for other electrically powered pipeline related activities. 
         [0006]    There exists a need in the industry for a device that can supply downhole power in a relatively harsh wellbore environment without causing interference with other necessary exploration and production activities. A device that can generate or supply downhole power without interfering with wellbore intervention activities would be highly desirable. A device that can provide electrical power, using the flowing fluids in the pipeline as a power source, along a remote pipeline route, also would be very beneficial. 
       SUMMARY OF THE INVENTION 
       [0007]    An apparatus and method for generating power from fluid flow in a conduit is disclosed. The apparatus may comprise a fan, the fan being comprised of a plurality of blades positioned circumferentially around a central cavity. The blades may be adapted for receiving fluid flow and transmitting energy of fluid flow to rotate the fan. An electromagnetic winding and a magnet may be provided as well. The fan may be configured for generating rotational movement of the magnet relative to the electromagnetic winding to produce electrical energy. The central cavity may be free from obstruction and may be configured for receiving objects inserted into the central cavity. 
         [0008]    In some embodiments of the invention, the magnet may be cylindrical in shape. The magnet may be connectively coupled to the fan with a gear or other energy transfer mechanism, the fan being adapted for movement of the energy transfer mechanism to cause rotational movement of the magnet relative to the electromagnetic winding. Other apparatus and methods for coupling the fan to the magnet or to the electromagnetic winding may be employed as well. 
         [0009]    In at least one embodiment of the invention, the conduit may be a production tubing, and the apparatus may be adapted for installation into a wellbore. In a wellbore having a production tubing, the production tubing having a first diameter, the apparatus may comprise an annular expansion zone. The annular expansion zone may be positioned circumferentially outside the first diameter of the production tubing. The fan may be positioned in the expansion zone to receive fluid flow in the expansion zone. The central cavity may be adapted for receiving wellbore tools as well. The electromagnetic winding may be cylindrical in shape. The electromagnetic winding also may be positioned circumferentially outside of the magnet. 
         [0010]    An electrical load may be connected to the electromagnetic winding. The electrical load may be selected from one or more of the following: sensor, sliding sleeve, telemetry mechanism, transducer, actuator, pump, processor, energy storage device, capacitor and controller. The electrical load may comprise an energy storage device, the energy storage device being adapted for storing electrical energy produced by the apparatus, wherein the energy storage device may be configured for supplying power during time periods when there is insufficient fluid flow within the apparatus to supply electrical power. 
         [0011]    An apparatus as described also may be employed for application in a pipeline. In this application, the apparatus may comprise a fan, the fan being comprised of a plurality of blades positioned circumferentially, the blades being adapted for receiving fluid flow and transmitting energy of the fluid flow to rotate the fan. A cylindrical magnet may be positioned circumferentially in relation to the fan, the fan being coupled to the magnet by a gear, an electromagnetic winding being positioned circumferentially with respect to the magnet, wherein the fan is configured for generating rotational movement of the magnet within the electromagnetic winding to produce electrical energy. The apparatus further comprises a central cavity within the plurality of blades, which allows for the passage of pipeline cleaning devices through the pipeline. 
         [0012]    In the application of the method for generating power in a wellbore, fluid flows through the wellbore. The wellbore has a conduit, such as a production tubing, which has a first diameter. The fluid is expanded into an annular expansion zone, the annular expansion zone being located circumferentially outside of the first diameter of the production tubing. Then, the fluid may impact upon a fan within the annular expansion zone. The fan may be comprised of a plurality of blades positioned circumferentially within the annular expansion zone. The fan may be coupled to a magnet, or in other embodiments, the fan may be coupled to an electromagnetic winding. The fan is rotated, which transmits rotational energy to cause the magnet to move relative to the electromagnetic winding, thereby producing electrical energy. 
         [0013]    Electrical energy may be stored in an energy storage device, such as a battery or capacitor. In other applications, the electrical energy may activate a sensor. The electrical energy may be employed to activate a sliding sleeve, a telemetry mechanism, a transducer, an actuator, a pump, an actuator, a processor, or the like. In some embodiments, the electrical energy may charge an energy storage device, battery or capacitor. The energy may be employed to activate a controller. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0014]    The invention may be illustrated by way of example as shown in the following Figures: 
           [0015]      FIG. 1  shows a partial cross-sectional view of the production tubing comprising a first embodiment of the apparatus of the invention as positioned in a wellbore; 
           [0016]      FIG. 2  is a longitudinal cross-sectional view of apparatus with details of the fan and blade configuration; 
           [0017]      FIG. 3  is a side cross-sectional view taken along line  3 - 3  of  FIG. 2 , showing the configuration of the first embodiment of the apparatus; 
           [0018]      FIG. 4  reveals a second embodiment of the invention, in longitudinal cross-section, showing a somewhat different configuration of the blade and fan assembly; 
           [0019]      FIG. 5  is a cross-sectional view taken along lines  5 - 5  of  FIG. 4 , revealing the structure of the second embodiment of the invention; and 
           [0020]      FIG. 6  shows a third embodiment of the invention as employed in a pipeline. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The invention is shown in several embodiments in the Figures, and persons of skill in the art will recognize that other embodiments having other configurations could be envisioned, which are within the scope and spirit of the disclosed invention. 
         [0022]    One advantage of the invention is that in some cases, the structure of the device facilitates the use of wellbore intervention operations during the time that the device is installed in the wellbore. Such operations may include, for example, the insertion of coiled tubing or wireline or cleaning devices into the wellbore and/or into the production tubing. Such operations may be performed without conflict with the apparatus of the invention, in part due to the fact that blades of the apparatus reside outside of the conduit first diameter, as further discussed herein. Likewise, for embodiments of the invention that are employed in pipelines, the cleanout of pipelines by pigging devices is facilitated in a similar manner. Thus, power may be generated by flowing fluid without substantial obstruction of the working area. 
         [0023]    Turning to  FIG. 1 , apparatus  20 ,  21  is shown positioned along a conduit  22  comprising production tubing  38  in a wellbore  27 . The wellbore  27  is installed within subterranean formation  28  by way of a cemented casing  30 . Optional energy storage devices  24 ,  25  are shown in electrical communication with apparatus  20 ,  21  respectively. In this configuration, wellbore intervention tools (not shown) may be lowered downwards into the production tubing  38  as needed during normal wellbore operations. 
         [0024]      FIG. 2  shows apparatus  20  in cross-section, with a central cavity  40  along the center of production tubing  38 . A fan  33  comprises a plurality of blades  35 ,  36  which are provided circumferentially around the central cavity  40 . Fluid flow through production tubing  38  proceeds along and within the first diameter  50  until the fluid reaches the annular-shaped expansion zone  39 , at which point the fluid may be expanded radially within the production tubing  38  so as to contact blades  35 ,  36  causing rotation of fan  33 . Blade  35  is connected to bearing  48 , which is provided in operable unison with magnet  44 . Rotation of fan  33  causes rotation of circular magnet  44  within the circular electromagnetic winding  46  to produce electricity. Housing  42  is connected to production tubing  38 , in one embodiment of the invention. A space  52  is provided in between the electromagnetic winding  46  and the magnet  44 . 
         [0025]    It should be recognized that other embodiments of the invention (not shown) which employ a rotating electromagnetic winding  46  with a stationary magnet  44  also could produce electrical current in a similar manner. So long as the magnet  44  moves relative to the electromagnetic winding  46 , current may be produced. Further, it is not necessary that such structures be circular, and many other geometries could be applied by persons of skill in the art. 
         [0026]      FIG. 3  shows a cross-sectional view along lines  3 - 3  of  FIG. 2 , in which further internal details of apparatus  20  are visible. Housing  42  surrounds electromagnetic winding  46 , which is circular and in this instance, is fixed in place. Magnet  44  rotates within the electromagnetic winding  46  when the magnet  44  is driven by gear  56 . Gear  56  receives mechanical force from teeth  54 . Coupler  53  rests between teeth  54  and magnet  44 . Teeth  54  are driven by the action of the plurality of blades  35 ,  36  constituting fan  33 . The fan  33  is driven in a circular motion by fluid passing through central cavity  40 , and the speed of the fan  33  is related to the velocity of fluid passing through central cavity  40 . 
         [0027]    In  FIG. 4 , a second embodiment of the invention is shown, with a close-up view of the blades provided circumferentially around central cavity  66 . For example, blades  62 ,  64  are shown as part of fan  65  extending into the central cavity  66 , and are positioned to receive fluid flow. Apparatus  60  further comprises support  69  in close association with blade  64 . Blade  64  is attached to first magnet  68 , which is provided adjacent bearing  70 , and adjacent wall  72 . A second magnet  74  is positioned on the outside of bearing, and is capable of magnetic communication with magnet  68 . Thus, when first magnet  68  is caused to move by fluid forces in the expansion zone  75  inpinging upon the plurality of blades, such as blades  62 ,  64 , then magnetic forces between first magnet  68  and second magnet  74  result in rotation of second magnet  74  about its central axis. This rotation of second magnet  74  inside the circular electromagnetic winding  76  causes the production of electrical current which may be transported within or outside of housing  78  and stored in an energy storage device  24 ,  25  as shown in  FIG. 1  for later use. 
         [0028]    In the configuration as shown in  FIG. 4 , wellbore intervention tools (not shown) may be lowered downwards into the production tubing and through central cavity  66  as needed during normal wellbore operations. 
         [0029]    Yet another embodiment of the invention is shown in  FIG. 6 . A pipeline  80  carries a fluid such as hydrocarbons, gas, water, or other fluid along fluid flow arrow  87 . The conduit  82  expands as it reaches apparatus  84 , providing an expansion zone similar to that shown in the other embodiments of the invention as described herein. Electrical power may be generated in a similar manner by action of the fluid upon blades (not shown in  FIG. 6 ) to turn a fan (not shown) causing electricity generation along conductive cable  89  to energy storage device  85 . The power thus generated and stored may be used for many different activities along the pipeline route, including but not limited to: providing illumination/lighting along the pipeline, activating security devices, providing cathodic protection from pipeline corrosion, or other uses that would be associated with pipeline activities. Further, the transmission of pigs along the pipeline for cleaning and other purposes are not hindered by the apparatus  84 , because the central cavity of the pipeline remains clear for transmission of devices through the conduit  82 . 
         [0030]    The components of system for power generation by movement of fluid and its various components, as illustrated by the invention, may be made from a wide variety of materials. The system may include DC generators, AC generators, asynchronous systems, synchronous systems, permanent magnets including rare earth magnets and the like. These materials may include metallic or non-metallic, magnetic or non-magnetic, elastomeric or non-elastomeric, malleable or non-malleable materials. Examples of suitable materials include metals, plastics, polymers, wood, alloys, composites and the like. If metals are employed, they may be selected from one or more metals, such as steel, stainless steel, aluminum, titanium, nickel, magnesium, or any other structural metal that is suitable for use in a high temperature and high pressure environment. Examples of plastics or polymers may include, but are not limited to, nylon, polyethylene (PE), polypropylene (PP), polyester (PE), polytetraflouroethylene (PTFE), acrylonitrile butadiene styrene (ABS), polyvinylchloride (PVC), polycarbonate, extruded organic thermosets such as polychloroprene and combinations thereof, among other plastics. The system may be molded, sintered, welded, machined or formed in a manner to make the required pieces for assembly. 
         [0031]    The invention is shown by example in the illustrated embodiments. However, it is recognized that other embodiments of the invention having a different configuration but achieving the same or similar result are within the scope and spirit of the claimed invention.