Abstract:
A downhole electrical generating apparatus providing power to downhole electronics. The apparatus includes a tubular having a wall forming a tubular space which receives a flow in a flow direction. A retractable electrical generating apparatus positionable in a first condition facing the flow and in a second condition substantially opening the tubular space. Also included is a method of providing power to downhole electronics.

Description:
BACKGROUND 
     Methods and apparatus for controlling downhole drilling and completion configurations are growing more complex and there is an ever increasing need for downhole control systems which include downhole computerized modules employing downhole computers for commanding downhole tools such as packers, sliding sleeves, valves, etc. based on input from downhole sensors. It will be appreciated that these control systems utilize downhole devices and circuits that require electrical power. Because of shortcomings associated with providing electricity via a wireline from the surface or via batteries housed in the downhole environment, downhole electric power generators have been suggested for use to provide power for downhole electronics. When turbines are employed as the downhole electric power generator, the turbine blades are provided within the flow path of the borehole, obstructing full bore access so that wireline or other operations cannot be performed, such as entry of completion equipment and other objects into the tubing, downhole of the level of the turbine. Other downhole electric power generators including turbines have been provided on a side of the bore so as not to significantly obstruct the main flow, but require a diversion of flow to move the blades. The diverted flow may not be as powerful as the flow through the main flow and the size of the electric power generator must be smaller to fit on the side of the tubing, both of which inevitably reduce the potential capacity for electric power generation. 
     BRIEF DESCRIPTION 
     A downhole electrical generating apparatus providing power to downhole electronics, the apparatus includes a tubular having a wall forming a tubular space which receives a flow in a flow direction; and, a retractable electrical generating apparatus positionable in a first condition facing the flow and in a second condition substantially opening the tubular space. 
     A method of providing power to downhole electronics, the method includes providing a retractable electrical generating apparatus within a flow passageway of a tubular, the retractable electrical generating apparatus positioned substantially perpendicular to a flow direction in a first condition and producing electricity using the retractable electrical generating apparatus in the first condition; and moving at least a portion of the retractable electrical generating apparatus to a position towards a wall of the tubular and providing a substantially clear borehole in the second condition. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG. 1  is a cross-sectional view of an exemplary embodiment of a retractable power turbine apparatus; 
         FIG. 2  is a cross-sectional view of the exemplary retractable power turbine apparatus of  FIG. 1  within a tubular; 
         FIG. 3  is a cross-sectional view of another exemplary embodiment of a retractable power turbine apparatus within a tubular; 
         FIG. 4  is a cross-sectional view taken along line I-I′ of  FIG. 3 ; 
         FIG. 5  is a cross-sectional view of yet another exemplary embodiment of a retractable power turbine apparatus; 
         FIG. 6  is a cross-sectional view of the exemplary retractable power turbine apparatus of  FIG. 5  within a tubular; 
         FIG. 7  is a cross-sectional view of still another exemplary embodiment of a retractable power turbine apparatus; 
         FIGS. 8A and 8B  are partial cross-sectional views of an exemplary turbine blade of  FIG. 7  in extended and retracted positions, respectively; and 
         FIG. 9  is a partial perspective view of the retractable turbine apparatus of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     A downhole electrical generating apparatus  10  in accordance with exemplary embodiments is shown in  FIGS. 1 and 2  for use in a borehole, such as a production well for producing oil, gas, or the like, for example. Such wells include a well casing, not shown, which may be positioned in the earth, and production tubing, not shown, connected to a tubular  12  of the downhole electrical generating apparatus  10 . An uphole section of production tubing is connectable to a first end  14 , such as one of an uphole or downhole end of the tubular  12  of the downhole electrical generating apparatus  10 , and a downhole section of production tubing is connectable to second end  16 , such as the other of an uphole or downhole end of the tubular  12 , of the downhole electrical generating apparatus  10 . The tubular  12  of the downhole electrical generating apparatus  10  includes a longitudinal axis  13  and a flow passageway that communicates with, and is generally in alignment with, uphole and downhole sections of production tubing. The tubular  12  includes a wall  18  providing a tubular space  20  for the flow passageway that has a first inner diameter  22 , substantially the same as a diameter of at least the connecting portions of the upper and lower sections of production tubing, for connecting therewith. The tubular space  20  also has a second inner diameter  24 , larger than the first inner diameter  22 , for providing a wall pocket  26  or side pocket that receives a retractable power turbine  30  of the downhole electrical generating apparatus  10  when a full bore is required in the production tubing and tubular  12  so that wireline or other operations can be performed downhole of the level of the retractable power turbine  30 . The longitudinal section of the tubular  12  that includes the wall pocket  26  may have different widths depending on the cross-section taken along the section. 
     With further reference to  FIGS. 1 and 2 , the retractable power turbine  30  of the downhole electrical generating apparatus  10  includes turbine blades  32 , which are positioned, in a first condition, within the flow  34  of the flow passageway in the tubular space  20 . The turbine  30  may have a smaller diameter than the first diameter  22  of the tubular  12 . The turbine  30  may be less than half of the first diameter  22 , but may be larger, as long as it is sized to fit within the wall pocket  26  in the second condition of the turbine  30 . That is, the turbine  30  folds down into the wall pocket  26  in the side of the tubular  12  in the second condition and substantially out of the flow  34 . The wall pocket  26  forms an upset on the outside of the tubular  12  which provides the necessary wall thickness and second diameter  24  to substantially remove the turbine  30  from the flow  34  in the second condition. Thus, the turbine  30  is provided substantially perpendicular to the direction of flow  34  in the first condition, and substantially parallel to the direction of flow  34  in the second condition. 
     During a production operation, production fluid flowing upwardly through the production tubing and the tubular  12  (or during injection operation, fluid flowing downwardly through the tubing) will rotate the turbine blades  32  when the turbine  30  is positioned in the first condition within the flow  34 . The blades  32  are connected to a center bearing  36 , and the turbine blades  32  rotate around the center bearing  36  and around rotation axis  31  of the turbine  30  due to the force of fluid in the flow  34  pushing past the blades  32 . The center bearing  36  is supported by a support rod  38  connected to the tubular wall  18  by a pivot  40 . The support rod  38  folds with the turbine  30  into the wall pocket  26 . Surrounding the turbine blades  32  is a sealed unit  42 , which contains coils  41  for a generator. The blades  32  are provided with magnets  44  at ends thereof that interact with the coils  41  of the sealed unit  42  when the blades  32  are rotated. That is, the movement of the magnets  44  near the coils  41  creates a flow of electrons, which can be harnessed into electricity in a known manner. The turbine  30 , including the coils  41  within the sealed unit  42 , the turbine blades  32  having the magnets  44 , the bearing  36 , and the support rod  38 , all move together from the first condition within the flow  34  for electricity production to the second condition substantially out of the flow  34  for providing a clear borehole. The movement from the first condition to the second condition, and from the second condition to the first condition, may be performed by a pushing or pulling force from a downhole tool inserted through the tubular  12  and physically engaging the turbine  30 , or alternatively by remote actuation. 
     While a coil containing sealed unit  42  has been disclosed as surrounding the turbine blades  32  of the turbine  30  of the downhole electrical generating apparatus  10 , it would also be within the scope of these embodiments to utilize the central bearing  36  as a rotor by connecting the central bearing  36  to a generator positioned outside of the flow  34 , such as within the wall pocket  26  or a separate upset within the wall  18 . Rotation of the bearing  36  may provide the necessary rotation for the generation of electricity in a generator. In such an embodiment, the central bearing  36  may transmit rotational energy via the support rod  38  to the generator. 
     Also, in yet another exemplary embodiment, instead of providing the coil containing sealed unit  42  as part of the retractable portion that is folded into the wall pocket  26 , the coils may remain fixed around or inside a circumference of the wall  18 , similar to coil containing unit  126  as will be further described below with respect to  FIG. 3 . In such an embodiment, the turbine blades  32  and the magnets  44  spin in the flow  34  in the first condition, and are retractable together into the wall pocket  26  in the second condition, but the coils remain fixed around the circumference of the wall  18  in both conditions. Also in such an embodiment, the support rod  38  may be positioned such that the turbine blades  32  are pulled into the wall pocket  26 , that is, the support rod  38  may be connected to an opposite side of the central bearing  36 , such as a downhole side of the central bearing  36  instead of an uphole side of the central bearing  36 , so that the support rod  38  does not interfere with the coils when the turbine is in the first condition. 
     Turning now to  FIGS. 3 and 4 , in another exemplary embodiment, a downhole electrical generating apparatus  100  includes a turbine  102  that rotates on an annular bearing  104  with no support in the center  106 . In such an embodiment, the blades  108  of the turbine  102  are mounted on pivot or swivel attachment  110  along the annular bearing  104  and can rotate back to the wall  112  of a tubular  114  housing the turbine  102  to provide a clear path. The blades  108  include a first end  116  pivotally attached, such as by but not limited to a swivel attachment  110 , the annular bearing  104  and a second end  118  closer to a central area  106  of the tubular space  120  within the tubular  114 . In a first condition, the blades  108  are extended so as to be substantially perpendicular to the direction of the flow  122 , so that the force of the flow  122  rotates the blades  108  about the annular bearing  104 . In a second condition, to substantially remove the blades  108  from the flow passageway through the tubular space  120 , the blades  108  may be pivoted downwardly so as to lie substantially flush with the wall  112  of the tubular  114  and parallel with a direction of the flow  122 . For electricity production, the turbine  102  may be surrounded by a coil containing unit  126 , as in the first embodiment, where magnets may be provided in the annular bearing  104  and/or ends  116  of the turbine blades  108 . As in the first embodiment, actuation from the first condition to the second condition may occur using a downhole tool or via remote actuation. While the annular bearing  104  and sealed unit  126  are shown embedded within the wall  114  of the tubular  112 , it would also be within the scope of these embodiments to form upsets within the wall  114  or other supporting structures about the wall  114  to support the annular bearing  104  and/or the sealed unit  126 . 
     Turning now to  FIGS. 5 and 6 , in yet another exemplary embodiment, a downhole electrical generating apparatus  200  includes a turbine  202  that rotates on an annular bearing  204  with no support in the center  206 , similar to the turbine  102  shown in  FIGS. 3 and 4 . Unlike the turbine  102  shown in  FIGS. 3 and 4 , the turbine  202  is pivotally connected to tubular  208 , as is the turbine  30  shown in  FIGS. 1 and 2 . Thus, the downhole electrical generating apparatus  200  includes a combination of features shown in the previous embodiments, and additional details and alternatives of the downhole electrical generating apparatus  200  may be derived from a review of the detailed descriptions of those embodiments. With reference again to  FIGS. 5 and 6 , the turbine  202  includes turbine blades  210  connected to the annular bearing  204  which may be rotatably supported within a sealed unit  212  for electricity production in a first condition when a flow  214  of fluid pushes past the turbine blades  210  causing rotation thereof. The turbine  202  is pivotally connected, such as by using a support rod  216  to the tubular  208  to fold the turbine  202  into wall pocket  218  in a second condition to provide a substantially clear borehole within the tubular  208 . 
     With reference to  FIGS. 7 ,  8 A- 8 B, and  9 , in still another exemplary embodiment, a downhole electrical generating apparatus  300  includes a turbine  302  that rotates on an annular bearing with no support in the center, similar to the previously described turbines  102  and  202 . Unlike the turbines  102  and  202 , however, the turbine blades  304  swivel sideways towards the wall of the tubular in the second condition instead of swiveling towards the wall in a downhole or uphole direction. The blades  304  are mounted on a rotor  306  on a swivel or pivot  308 . Magnets  310  are also positioned on the rotor  306 . When the flow through the tubular causes the blades  304  to spin, the rotor  306  spins relative to a coil-containing stator  312  containing coils  314 , where the stator  312  may be positioned in the tubular, as in the embodiment shown in  FIG. 3 .  FIG. 8A  shows the turbine blade  304  extended in the first condition within the flow for rotating the rotor  306  relative to the stator  312 .  FIG. 8B  show the turbine blade  304  retracted in the second condition, substantially out of the flow, or at least substantially out of the central region of the tubular, to provide a substantially clear borehole in the second condition. As shown in  FIG. 9 , the blade  304  is pivotally connected to an uphole end  316  and a downhole end  318  of the rotor  306 . In an exemplary embodiment, a magnet  310  is extended between the uphole end  316  and the downhole end  318  of the rotor  306 , and between each adjacent pair of blades  304 . Alternatively, each turbine blade  304  may include a magnet at each rotor side end thereof. 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material or blade shape to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.