Abstract:
Apparatus for calculating service life expectancy of wellbore intervention tools comprising one or more sensors, power means, control means and wireless connectivity means. Also a method of the measuring and calculating the service life expectancy of wellbore intervention tools using this apparatus.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0001]    The present invention relates generally to a method and apparatus to keep track of the service life expectancy of wellbore intervention tools, and more particularly to an autonomous apparatus that is intended to follow the use and exposure of a wellbore intervention tool while continuously calculating a prediction of the remaining life expectancy of the tool monitored. 
         [0002]    The tool service life is a percentage number and is based on a generic set of algorithms characterizing the influential failure-mechanisms verses exposure, workload, and time. The Tool Service Life Sensor (“TSLS”) is provided with wireless connectivity and may be interrogated in the well or at the surface. Upon interrogation, the TSLS will prompt the mission, the life expectancy left, tool identity and status, as well as particular events (above certain expectation limits). The TSLS may be integrated and be incorporated as part of a downhole intervention tool or it may have its own housing. 
         [0003]    For those skilled in the art, this is not the downhole-tool version and substitution for an airplane “flight recorder” or “black box,” but a mission recorder telling the operator the status of the tool and how much future or “usable” life expectancy the tool provides. This is calculated and expressed directly by the TSLS in percentage design life left, and is based on historic (recorded) use. Further, it is an estimate of how many hours of use the life expectancy prediction represents. Secondarily, but just as importantly, the TSLS provides as output information the occurrence of damage-events as recorded outside a defined level. 
         [0004]    U.S. Patent Application Publication No. 2006/0238161 A1, to Rusnell et al., describes a system that records the use versus load with time. This invention is intended for attachment to rental equipment in order to manage their charges and service. The latter is related to the use and workload recorded. This invention does not have the mission, or the ability, to predict the remaining “life” of a tool. Further, it does not include wireless connectivity, which in many applications is required as the tool and the TSLS target may be located in a remote location, non-accessible with a cable connection. 
         [0005]    U.S. Patent Application Publication No. 2006/0085134 A1, to Dion et al., is a downhole memory recorder to be used in a well to record the usage of a tool. Operating data collected as well as peak conditions from the recorder are downloaded and used to evaluate the life and status of the mission tool in a surface database. This unit is not autonomous and does not on its own calculate the remaining life of a mission tool. 
       SUMMARY OF THE INVENTION 
       [0006]    By the present invention all decisions and calculations of expected lifetime and occurrence are performed by sets of static algorithms describing the governing failure mechanisms considering the life of the unit verses time, load, use, and/or exposure, of which magnitude and impact are measured by an application-specific parametric sensor array of the TSLS. Consequently, lifetime prediction of this invention is static as described, and not a process based on human resources evaluating data records like those described in previous art. 
         [0007]    According to the present invention, there is provided apparatus for calculating service life expectancy of wellbore intervention tools, the apparatus comprising one or more sensors, power means, control means, and wireless connectivity means. The application also provides a method for measuring the service life expectancy of wellbore intervention tools, in which apparatus according to the present invention is positioned in a wellbore adjacent to or near a tool to be monitored, measuring one or more physical properties with the one or more sensors in the apparatus, recording and processing the data obtained from the sensors, and calculating the expected life of the tool being monitored using the data collected. Preferred and optional features of the apparatus and method of the present invention will be clear from the accompanying claims and from the detailed description of an embodiment which follows. 
         [0008]    All wellbore equipment has a certain life expectancy that is generally based on technology, material properties, ruggedness, and compatibility, to mention a few non-limiting parameters. Any use of a tool in a well will induce wear on the parts of which it consists. The wear may be categorized and broken down into segments of, for example, wear and tear, all of which may be calculated based on environment, material properties, function, and exposure. Further, in any tool there will be functions or components that are likely to wear out and fail before others due to the nature of the tool and its parts, as well as the technology utilized. Consequently, such a parameter or parameters will be the life-limiting factors of the tool and the governing factors for the service and work-over to proceed. 
         [0009]    For the purpose of the invention, the governing life-limiting parameters are referred to herein as the “apparent failure mechanisms of the tool.” Further, and for the continuation of this process, the governing failure mechanisms of a mission intervention tool will be the criteria to calculate and predict its lifetime expectancy. Consequently, in general, all failure mechanisms may be characterized and their influence on the tool total life expectancy may be predicted based on use, workload, and time. Further, the use may be categorized as heavy or light and be dependent on which parameter and load that a user selects to distinguish between the two. Again, the outcome is a predictable reduction of a mission or tool service-life. 
         [0010]    This apparatus is by definition a generic type “Tool Service Life Sensor” and will prompt the user with the status of the tool and how much more use it will take before it is to be taken out of service for overhaul or replacement. The life expectancy is calculated based on how many of the required number of algorithms that characterize the governing failure mechanisms upon which the tool-life is based and what physical property parameters or work-load are associated with them. The calculation of the tool life is in turn linked to integral sensor of the apparatus that is sequentially recorded to memory on each event and by time. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0011]    Referring now to the drawings, wherein like elements are numbered alike in the several FIGS.: 
           [0012]      FIG. 1  shows an outline schematic of the Tool Service Life Sensor (“TSLS”) with its major components; and 
           [0013]      FIG. 2  is a diagrammatic block diagram illustrating the electrical and functional configuration of the TSLS. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0014]    A first embodiment of the Tool Service Life Sensor (“TSLS”) and associated equipment are shown in  FIG. 1  and  FIG. 2 . Referring to  FIG. 1 , a typical embodiment of the TSLS is illustrated. A housing  1  holds a main frame  3  containing components for the TSLS. The main frame  3  hosts a battery  30 , a sensor package  10 , a controller/recorder board  2 , an electromagnetic antenna  22 , and a wired connectivity element  9 . For practical means, the housing  1  provides an electrical feedthrough  8  for the operation of and connection to tools operated electrically. Finally, the housing  3  is provided with a threaded seal connection  7  for attaching to a mission tool (not shown). 
         [0015]    The TSLS  3  communicate wirelessly to a remote link  5  which is controlled by a controller/computer device  4 . The controller/computer device  4  may be a traditional PC computer running a software application to interrogate the TSLS. Wireless connectivity between the units is indicated by the reference numeral  6 . The wireless connectivity  6  is through electromagnetic means and is functional in air at the surface and in fluids or gas which may be present in the wellbore. 
         [0016]    Referring to  FIG. 2 , a functional block diagram of the TSLS is shown. The first building block is the sensor package  10 . The sensor package  10  may consist of one or more sensors  11 ,  12 ,  13 ,  14 ,  15 ,  16 ,  17 ,  18 , etc. The sensors may measure properties selected from the following non-limiting list: temperature, temperature difference, pressure, differential pressure, vibration, chock, electric field, magnetic field, acceleration, load, displacement means, acoustic type, resistivity, relative humidity, thermal conductivity, pH, electrical potential AC/DC, electrical current AC/DC, tension, compression, torque, shear force, inclination, magnetic orientation, toolface, gravity, flow, turbidity, density, displacement, dimension, radiation, speed, frequency, weight, buoyancy, ratio-metric type, electrical event type, as well as ambient conditions inside the housing  1 . The sensor package  10  may consist of one or more sensors, or a combination of one or more of all sensors listed. 
         [0017]    Input signals from the sensor package  10  is multiplexed by a multiplexer  20  and is amplified/linearized accordingly by an amplifier section  21 . In turn, the output of the amplifier section  21  is fed to a controller  24  for acquisition. Due to the wide temperature operating range of the TSLS, the data acquisition is provided with a stable reference  32  for signal processing and comparison. 
         [0018]    The TSLS is powered by the battery  30  and provides a stable output to a power supply  29 . The power supply  29  has a power supply output  31  which is the main electric source for the circuits and sensors of the TSLS. To keep track of time the controller  24  is connected to a timer or clock device  23  which is a stable time source to keep track of time even at elevated conditions. For those skilled in electronic arts, the times or clock device  23  of the TSLS may be a doubly rotated SC (SC=Sensitivity Cut) quartz crystal resonator. The TSLS is autonomous, and executes a program application set up and managed by the controller  24 . The program application is user defined, and is based upon analysis of the failure mechanisms of the mission element tool. Data processed and events recorded are stored in memory sections  26 ,  27 , and  28 . The memory technology used may be any volatile or non-volatile type. 
         [0019]    Connectivity is provided by a modem  25  and the electromagnetic antenna  22 . The TSLS also provides the wired connectivity  9  which may be used for hardwired communication where practical. 
         [0020]    Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.