Abstract:
Autonomous control of a wellbore tool is provided by programming a memory module of a processor with a database having data relating to a selected parameter of interest; conveying a sensor and the processor along the wellbore; and activating the wellbore tool if the processor determines that a measurement provided by the sensor correlates with the database data. The processor may correlate the sensor measurements with a predetermined pattern associated with the data, a preset value, and/or a preset range of values. Well tool activation may occur when the processor finds: a substantial match between a predetermined pattern and at least one measured value; a present value and at least one measured value, and/or a preset range of values and at least one measured range of values. Also, activating the well tool may occur only if a measurement from a second sensor meets a preset criteria.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 11/858,077, filed Sep. 19, 2007, which claims priority from U.S. Provisional Application Ser. No. 60/845,912 filed on Sep. 20, 2006. This application is also a continuation-in-part of U.S. patent application Ser. No. 12/049,714 filed Mar. 17, 2008. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    1. Field of the Disclosure 
         [0003]    The disclosure relates to a method and an apparatus for the autonomous control of downhole tools. 
         [0004]    2. Background of the Disclosure 
         [0005]    Hydrocarbons are recovered from underground reservoirs using wellbores drilled into the formation bearing the hydrocarbons. The construction and subsequent use of a well for recovering hydrocarbons typically involves the deployment of a variety of tools into a wellbore. Conventionally, the effective operation of these tools while in the wellbore may require some form of control. Certain conveyances such as wirelines can provide a relatively fast rate of data transfer between the surface and a downhole tool. Thus, such devices may be operated from the surface. However, downhole tools used in connection with conveyance devices such as drill pipe, coiled tubing, slick-lines and drop tools may have inadequate access to communication uplinks and downlinks. Thus, surface personnel may have limited operational control over such tools. 
         [0006]    The present disclosure addresses the need to provide control for tools deployed in a downhole environment. 
       SUMMARY OF THE DISCLOSURE 
       [0007]    In aspects, the present disclosure provides a method for autonomously controlling wellbore tools. An illustrative method may include programming a memory module of a processor with a database having data relating to a selected parameter of interest; conveying a sensor and the processor along the wellbore; and activating a wellbore tool positioned in the wellbore if the processor determines that a measurement provided by the sensor correlates with the data in the database. In aspects, illustrative data may relate to: a geological parameter, a geophysical parameter, a petrophysical parameter, a wellbore parameter, a configuration of a wellbore tubular, a lithological parameter, and/or casing collars. The wellbore tool to be activated or controlled may include, but is not limited to, a perforating gun, a sensor, a formation evaluation tool, a production control device positioned in the wellbore, a seismic source, and/or a seismic receiver. Illustrative sensors include, but are not limited to, a formation evaluation tool, a casing collar locator, a pressure sensor, a temperature sensor, an NMR tool, a wellbore caliper, a directional survey tool, a fluid analysis tool, an accelerometer, and/or an odometer. In aspects, the method may include programming the processor to correlate the sensor measurements with a predetermined pattern associated with the data in the database, a preset value, and/or a preset range of values. In aspects, the method may include conveying a second sensor along the wellbore, and wherein the activating of the well tool does not occur unless a measurement from the second sensor meets preset criteria. The method of autonomous control may be employed for devices conveyed via a drill pipe, a coiled tubing, a slickline, or a free-fall device. 
         [0008]    In aspects, the present disclosure provides an apparatus for autonomous control of a tool in a wellbore. An exemplary apparatus may include a well tool, a sensor associated with the well tool, a memory module programmed with data relating to a selected parameter of interest, and a processor in communication with the sensor and the memory module. The processor may be configured to activate the well tool if the processor determines that a measurement provided by the sensor correlates with the data in the database. In aspects, the present disclosure also provides a system for servicing a wellbore formed in an earthen formation. The system may include a rig, a conveyance device configured to convey the well tool into the wellbore, a well tool positioned along the conveyance device, a sensor positioned along the conveyance device, a memory module programmed with data relating to a selected parameter of interest, and a processor in communication with the sensor and the memory module. The processor may be programmed with: a predetermined pattern associated with the data in the database, a preset value, and/or a preset range of values. The processor may be programmed to activate the well tool when the processor finds: a substantial match between a predetermined pattern and at least one measured value, a preset value and at least one measured value, and/or a preset range of values and at least one measured range of values 
         [0009]    Examples of the more important features of the disclosure have been summarized (albeit rather broadly) in order that the detailed description thereof that follows may be better understood and in order that the contributions they represent to the art may be appreciated. There are, of course, additional features of the disclosure that will be described hereinafter and which will form the subject of the claims appended hereto. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0010]    For detailed understanding of the present disclosure, reference should be made to the following detailed description of the preferred embodiment, taken in conjunction with the accompanying drawing: 
           [0011]      FIG. 1  schematically illustrates an elevation view of a drilling system utilizing autonomous downhole control in accordance with one embodiment of the present disclosure; 
           [0012]      FIG. 2  functionally illustrates a control device made in accordance with one embodiment of the present disclosure; and 
           [0013]      FIG. 3  is illustrative chart of measurements of a selected parameter of interest that may be represented by data in a database accessed by a control device made in accordance with one embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    The present disclosure relates to devices and methods for autonomous control of tools used in a wellbore. The present disclosure is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present disclosure with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. Further, while embodiments may be described as having one or more features or a combination of two or more features, such a feature or a combination of features should not be construed as essential unless expressly stated as essential. 
         [0015]    Referring initially to  FIG. 1 , there is shown a conventional drilling tower  10  for performing one or more operations related to the construction, logging, completion or work-over of a hydrocarbon producing well. While a land well is shown, the tower or rig can be situated on a drill ship or another suitable surface workstation such as a floating platform or a semi-submersible for offshore wells. The tower  10  includes a stock  12  of tubular members generally referred to as drill string segments  14 , which are typically of the same and predetermined length. The tubulars  14  can be formed partially or fully of drill pipe, metal or composite coiled tubing, liner, casing or other known members. Additionally, the tubulars  14  can include a one way or bi-directional communication link utilizing data and power transmission carriers such fluid conduits, fiber optics, and metal conductors. The tubulars  14  are taken from the rod stock  12  by means of a hoist or other handling device  18  and are joined together to become component parts of the drill string  20 . In embodiments, the tubular  14  may be “stands.” As is known, a stand may include a plurality of pipe joints (e.g., three joints). At the bottom of the drill string  20  is a bottomhole assembly (BHA)  22  illustrated diagrammatically in the broken-away part  24  that is adapted to form a wellbore  26  in the underground formation  28 . The BHA includes a housing  30  and a drive motor (not shown) that rotates a drill bit  32 . 
         [0016]    The BHA  22  includes hardware and software to provide downhole “intelligence” that processes measured and preprogrammed data and writes the results to an on-board memory and/or transmits the results to the surface. In one embodiment, a processor  36  disposed in the housing  30  is operatively coupled to one or more downhole sensors (discussed below) that supply measurements for selected parameters of interest including BHA or drill string  20  orientation, formation parameters, and borehole parameters. The BHA can utilize a down hole power source such as a battery (not shown) or power transmitted from the surface via suitable conductors. In aspects, the present disclosure provides devices and methods for controlling tools and equipment positioned along the drill string  20  and/or the BHA  22 . 
         [0017]    It should be understood that the BHA  22  is merely representative of wellbore tooling and equipment that may utilize the teachings of the present disclosure. That is, the devices and methods for autonomous control of the present disclosure may also be used with other equipment, such as survey tools, completion equipment, etc. 
         [0018]    Referring now to  FIG. 2 , there is shown an embodiment of a tool control device  100  that utilizes autonomous control in accordance with the present disclosure. In one arrangement, the tool control device  100  may include a processor  102 , a memory  104  accessible by the processor  102 , and a sensor  106 . The wellbore tool control device  100  may also include a power source such as battery pack  108 , a clock  110 , and other suitable devices for supporting operation of the processor  102  and the sensor  106 . The tool control device  100  may be configured to operate or activate a wellbore device  112 , which may be any wellbore tool that is configured to perform any number of wellbore tasks. The memory  104  may be configured to store data written to the memory  104  at the surface, or “pre-loaded” data. As will be described in greater detail below, the processor  102  may be programmed with instructions to activate or deactivate the wellbore tool  112  upon determining that a measurement or measurements provided by the sensor  106  correlates in a prescribed manner with the data in the memory  108 . The “preloaded” data may relate to any detectable naturally-occurring or man-made feature, object, or condition that is present in the wellbore  114  or the adjacent formation  116 . In one configuration, the processor  102  is programmed to correlate measurements of the sensor  106  with a preset activation threshold value within the data in the memory  104 . The preset activation threshold value may be a value, range of values, or pattern or sequence of values. In one aspect, for example, a correlation may include a substantial numerical match between a measured value and preloaded value for a given parameter. 
         [0019]    In embodiments, the preloaded data type and values are selected, compiled and ordered in a manner that characterizes a specific location, feature, or depth along the wellbore  114 . The data may relate to a geological parameter, a geophysical parameter, a petrophysical parameter, and/or a lithological parameter such as porosity, resistivity, gamma ray, and density for a formation intersected by the wellbore  114 . The data may also relate to a wellbore parameter such as azimuth, inclination, and/or wellbore diameter that describes a trajectory or dimensions of the wellbore  114 . Other suitable data may relate to a configuration of a wellbore tubular such as a liner or casing installed in the wellbore  114  or the number and/or depth location of casing collars in the wellbore  114 . 
         [0020]    The sensor  106  provides measurements that enable the processor  102  to determine whether the tool control device  100  is adjacent to or near a specific location, feature, or depth along the wellbore  114 . For example, the sensor  106 , which may include two or more sensors, may be configured to directly or indirectly detect or measure one more parameters discussed above that relate to the wellbore  114  or the formation  116 . Exemplary sensors include, but are not limited to, formation evaluation tools, radiation detectors, gamma ray detectors, casing collar locators, pressure sensors, temperature sensors, NMR tools, wellbore calipers, directional survey tools, fluid analysis tools, accelerometer, odometers, magnetometers, gyroscopes, etc. It should be understood that the sensor  106  may include a suite of sensors and the database may include data for two or more different types of parameters. 
         [0021]    Referring now to  FIG. 3 , there is shown an illustrative criteria that may be utilized by the processor  102  for correlating measurements from the sensor  106  with the data in the memory  104 .  FIG. 2  depicts an illustrative gamma ray plot  120  along a section of a wellbore. Also shown is a casing  122  and casing collars  124 . In one arrangement, the plot  120  or a selected portion of the plot  120  is digitized and preloaded in the memory  104  ( FIG. 2 ). In such an arrangement, the processor  102  ( FIG. 2 ) may be programmed to monitor the output of the sensor  106  ( FIG. 2 ), which may be a gamma ray detector, for gamma ray measurements that are the same or similar to the gamma ray value or values at the region labeled  126 . The preloaded value or values may be expressed as a maxima and/or a minima, a sequence of maxima and/or minima or any other pattern of values or data order that uniquely identifies that particular depth or location in the wellbore. In another arrangement, the processor  102  ( FIG. 2 ) may be programmed to monitor the output of the sensor  106  ( FIG. 2 ) to detect and count the number casing collars  124  until a preset number of casing collars  124  have been reached. Once the processor  102  detects the preset value, values or pattern within the sensor measurements, the processor  102  may initiate one or more preset actions. 
         [0022]    The nature or types of actions that may be autonomously initiated by the processor  102  depend in part on the tooling that is conveyed into the wellbore or is already present in the wellbore. Depending on the tooling, the processor  104  may issue a signal that instructs the tool to energize or de-energize, to move between power states (e.g., sleep to full power), to start or stop operation for a specified period, or switch between operating modes (e.g., “measure only” to “measure and record to memory”). For instance, the processor  104  may programmed to fire a perforating gun, initiate the inflation of a packer, release an additive, or activate a well stimulation tool. In other arrangements, the processor  104  may operate devices that may be used to investigate the formation  116  such as formation evaluation tools, seismic sources, or seismic receivers. In still other embodiments, the processor  104  may operate production control devices; e.g., valves that may be shifted between open and closed positions. The processor  104  may transmit the signals to the tool or tools via wire (e.g., electrical or optical) or wirelessly. It should be understood that the signals need not be transmitted directly to the tool. Rather, the processor  104  may control a power source or supply that energizes the tool. 
         [0023]    In embodiments, the processor  102  may be programmed to monitor multiple parameters in conjunction with the activation of the tool  112 . For instance, after the processor  102  determines that the sensor measurements correlate in a desired manner with the preloaded data, the processor  102  may determine whether one or more separate parameter set points or thresholds are satisfied (e.g., pressure, temperature, expiration of a time delay period, wellbore fluid chemistry, etc.). If so, the processor  102  may proceed with activation of the tool  112 . If not, the processor  102  may be programmed to wait until the parameter set points or thresholds are satisfied, abort the activation sequence, or take some other preprogrammed steps. 
         [0024]    It should be appreciated that the tool control device  100  may provide self-directed and intelligent control of wellbore equipment, which may reduce or eliminate the need for human intervention in the operation of such wellbore equipment. Thus, the tool control device  100  may be employed on conveyance devices that have either limited or no data and/or power transfer from the surface. Thus, the conveyance device  110  may be a drill pipe, a coiled tubing, or a slickline. In embodiments, the tool control device  100  may also be configured as a free-fall device that is dropped into a well. 
         [0025]    In certain embodiments, the memory  108  may be programmed with data that is preloaded at the surface. Thus, the processor  102  may access the memory  104  as needed during deployment. In embodiments, the processor  102  may be configured to write data to the memory  104  while downhole. That is, the data in the memory  104  may be dynamically updated. For example, the processor  102  may maintain a historical record of the number of casing collars that have been detected while being tripped downhole and utilize that information while being tripped out of the wellbore. In another example, one or more formation evaluation tools may detect a transition into a shale layer or a sand layer. The processor  102  may maintain a historical record of the different layers and formations that have been traversed for later use. 
         [0026]    In one exemplary mode of operation, the tool control device  100  may be utilized to fire a perforating gun at a specified depth in the wellbore. At the surface, a pre-existing well log is used to identify certain parameters that may be used to uniquely characterize the region to be perforated. The parameter, for example, may be a gamma ray log and a particular sequence of previously logged values for gamma ray emissions may uniquely characterize that region. Thus, the memory  104  may be preloaded with that sequence of previously logged gamma ray values and the processor  102  may be programmed to fire a perforating gun once the sensor  106  measures gamma ray emissions that, within a specified tolerance, match the preloaded values. The processor  102  may also be programmed with a minimum temperature and/or pressure that should also exist in order to fire the perforating gun. Thereafter, the tool control device  100  along with the perforating gun (shown generically as tool  112 ) is conveyed into the wellbore  114 . In either the trip into the wellbore  114  or the trip out of the wellbore  114 , the processor  102  continually monitors the output of the sensor  106 . Once the output of the sensor  106  indicates that the gamma ray emissions match that of the preloaded sequence and the processor  102  confirms that the pressure and temperature values are within prescribed ranges, the processor  102  sends a signal that fires the perforating gun. It should be appreciated that this wellbore operation did not require a prior run to determine the measured depth for the region to be perforated and did not require the well operator to monitor measured depth as a necessary element in order to operate the perforating gun. Rather, as should be appreciated, the processor  102  has been supplied with sufficient intelligence to locate the region to be perforated and take the necessary actions to perforate that region. While the mode of operation has been discussed in the context of a formation perforation activity, it should be understood that the same techniques may be applied to any other activities that may be undertaken during the drilling, completion, logging, recompletion or workover of a well. 
         [0027]    It should be understood that the teachings of the present disclosure are not limited to tooling conveyed by rigid carriers such as drill strings, such as that shown in  FIG. 2 . In embodiments, the above-described methods and devices may be employed on non-rigid carriers such as slick lines. In still other embodiments, the above-described methods and devices may be used in connection with drop survey devices that are released into the wellbore. 
         [0028]    While the foregoing disclosure is directed to the preferred embodiments of the invention, various modifications will be apparent to those skilled in the art. It is intended that all variations within the scope of the appended claims be embraced by the foregoing disclosure.