Abstract:
The present invention provides a mechanism to remotely initiate actuation of a device positioned in a borehole. The disclosure includes a magnetically initiated actuation mechanism.

Description:
FIELD 
       [0001]    The present invention relates generally to a remotely initiated actuation mechanism, and in particular though non-limiting embodiments, to a series of electromagnetic sensors positioned in a tubing string arranged to initiate an actuator when a device is passed through the tubing. 
       BACKGROUND 
       [0002]    A borehole is generally a narrow shaft bored in the ground, either vertically or horizontally. Boreholes are typically employed in various industries for a variety of purposes. For example, boreholes may be constructed for resource extraction (e.g. petroleum or natural gas). Generally, a borehole will have a pipe (tubing or casing) extending into the borehole. The tubing may provide resistance against caving and/or collapsing of the borehole. 
         [0003]    Boreholes typically have relatively small diameters and it is often necessary to perform certain actions and/or activities within a borehole. These down-hole activities require the ability to initiate the action and/or activity at the proper location and/or depth within the borehole. For example, actuators may be employed in a down-hole environment to perform down-hole tasks such as shifting valves or sliding sleeves in a resource extraction borehole. Unfortunately, the proper location and/or depth within a borehole must generally be manually determined, which can lead to inaccurate locations and/or delays in initiating the down-hole activities. 
         [0004]    Accordingly, there is need for a mechanism which provides the ability to initiate down-hole activities automatically when a device is properly located in a down-hole environment. 
       SUMMARY 
       [0005]    In an example embodiment of the present disclosure, a magnetically initiated actuation mechanism is provided, including: a first assembly comprising a plurality of electromagnetic sensors disposed within a tubular; and a second assembly comprising a means for generating magnetic fields. The second assembly is configured such that it can be conveyed through said tubular. The means for generating magnetic fields are configured such that the means for generating magnetic fields align with the electromagnetic sensors when the second assembly is conveyed to a point within the tubular containing the electromagnetic sensors. The electromagnetic sensors are configured to detect at least one of presence and absence of said magnetic fields. The electromagnetic sensors are further configured to initiate activation of an associated actuator. The actuator may be configured to engage at least one of a hydrostatic valve, battery operated motor, explosive, and incendiary device. The magnetically initiated actuation mechanism may further include additional sensors capable of sensing at least one of pressure, temperature, vibration, and flow rates. The means for generating magnetic fields may be a series of permanent magnets. 
         [0006]    In an example embodiment of the present disclosure, a method of initiating down-hole actuation is provided, including: incorporating electromagnetic sensors in tubing of a borehole; incorporating a means of generating magnetic fields into a second device configured to be passed through the tubing of the borehole; and initiating the down-hole actuation when the means of generating magnetic fields is aligned with the electromagnetic sensors. The electromagnetic sensors are configured to initiate activation of an associated actuator. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0007]      FIG. 1  is an isometric view of a magnetically initiated actuation mechanism as a conveyed device approaches sensors according to an exemplary embodiment. 
           [0008]      FIG. 2  is an isometric view of a magnetically initiated actuation mechanism as a conveyed device aligns with sensors according to an exemplary embodiment. 
       
    
    
     DESCRIPTION 
       [0009]    Embodiments of the present invention include a series of electromagnetic sensors positioned in a tubing string. The electromagnetic sensors may be responsive to polarity, strength or absence/presence of an external magnetic field. In embodiments, a second device containing permanent magnets or other means of generating a magnetic field may be conveyed through the tubing string containing the electromagnetic sensors. The magnets may be arranged in sequence and spaced such that their relative position will become aligned with the electromagnetic sensors as the second device is conveyed to a point within the tubing containing the electromagnetic sensors. When the second device passes through the tubing, the electromagnetic sensors are configured to detect the presence of the magnets, and the detection of the magnets is configured to initiate an actuator or start a timer for an action to be taken in the borehole. 
         [0010]    In one embodiment shown in  FIG. 1 , the electromagnetic sensors  1  are placed in the wall of the tubing  2 . The tubing wall may also contain sense electronics, a valve or other actuation device and/or a battery assembly (not shown). As shown, conveyed device  3  has a series of circumferential magnets  4 . 
         [0011]    The conveyed device is lowered or pumped through the tubing.  FIG. 1  shows the conveyed device  3  as it approaches the wall of tubing  2  containing the electromagnetic sensor array. In  FIG. 2 , the conveyed device  3  has moved to a point where the magnets  4  are aligned with electromagnetic sensors  1 . Electronics in either conveyed device  3  or wall of tubing  2  may receive a response from with electromagnetic sensors  1 , confirming the location of conveyed device  3  within the borehole and aligned with wall of tubing  2 . The electronics may then relay a signal such that a valve or similar down-hole mechanism is actuated, providing hydraulic energy to perform borehole tasks at that location. 
         [0012]    In practice, the invention may be used for common borehole actions such as shifting valves or sliding sleeves, and setting or releasing anchors or packers. The electronics may incorporate other sensors such as pressure, temperature, vibration or flow, and one or a combination of conditions may be required by the electronics to initiate actuation. Accordingly, the combination of electromagnetic sensors with other sensors may require both proper location and proper conditions to initiate a down-hole activity. The conveyed device may be dropped, lowered on a slickline, tubing conveyed, or attached to a plug or pig and pumped through the tubing. The actuator may trigger a hydrostatic valve, battery operated motor, explosive or incendiary device. 
         [0013]    While the embodiments of the present disclosure are described herein with reference to various implementations and exploitations, it will be understood that these embodiments are illustrative and that the scope of the inventions is not limited to them. Many variations, modifications, additions, and improvements are possible, including the application of a similar screen to different species of fungi. Further still, any steps described herein may be carried out in any desired order, and any desired steps may be added or deleted.