Abstract:
A method and system for analyzing a core sample from a wellbore, where the analysis takes place in the field and proximate the wellbore. The system includes trailers adjacent one another. One of the trailers can include a unit for scanning the core sample and obtaining information within the sample. Other trailers can include units that further analyze the core, such as by grinding, laser spectroscopy, and Raman spectroscopy. The core sample scanning involves a computerized tomography (CT) scan, where a length of core is analyzed in the scanning unit. The unit includes a manipulator system for moving the core sample through a rotating scan source in the scanning unit.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present disclosure relates in general to a method and system for analyzing a core sample from a wellbore. More specifically, the present disclosure relates to a method and system for evaluating a core sample from a wellbore with computerized tomography. 
         [0003]    2. Description of Prior Art 
         [0004]    Various techniques are currently in use for identifying the presence of hydrocarbons in subterranean formations. Some techniques employ devices that emit a signal from a seismic source, and receive reflections of the signal on surface. Others involve disposing logging devices downhole in a wellbore intersecting the subterranean formation, and interrogating the formation from within the wellbore. Example downhole exploration devices include seismic tools that can transmit and receive seismic signals, or ones that simply receive a seismic signal generated at surface. Other devices collect and sample fluid from within the formation, or from within the wellbore. Nuclear tools are also employed that direct radiation into the formation, and receive radiation that scatters from the formation. Analyzing the scattered radiation can provide information about fluids residing in the formation adjacent the wellbore, the type of fluid, and information about other materials next to the wellbore, such as gravel pack. 
         [0005]    Logging downhole also is sometimes done while the wellbore itself is being drilled. The logging devices are usually either integral with a drill bit used during drilling, or on a drill string that rotates the drill bit. The logging devices typically are either nuclear, seismic, can in some instances optical devices. In some instances, a core is taken from the wellbore and analyzed after being retrieved to the surface. Analyzing the core generally provides information about the porosity and/or permeability of the rock formation adjacent the wellbore. Cores are generally elongated cylindrical members and obtained with a coring tool having an open barrel for receiving and retaining the core sample. 
       SUMMARY OF THE INVENTION 
       [0006]    Disclosed herein is an example of a system for analyzing a core sample and which includes a first mobile enclosure having a scan system, a second mobile enclosure adjacent the first mobile enclosure, a loading assembly having an end coupled to the scan system and that projects into the second mobile enclosure, and a loading cover on a portion of the loading assembly that projects into the second mobile enclosure, and that selectively receives the core sample. The system can further include a hatch assembly mounted between the first and second mobile enclosures and circumscribing the loading assembly. Stations are optionally included in the second mobile enclosure where sections of the core sample are removed for further analysis. The system can further include a third mobile enclosure proximate the first and second mobile enclosures, and a laser based material analyzer in the third mobile enclosure. In an example, a manipulator is included with the system and that is in the first mobile enclosure, manipulator includes a core carrier on which the core sample is selectively disposed, and that selectively and in a synchronized fashion reciprocates the core sample within the scan system. In this example, the manipulator further includes a manipulator base in the first mobile enclosure, and a manipulator arm that is selectively and telescopingly urged along the manipulator base. Further in this example the scan system has a gantry system with a scan source that emits scan energy and orbits about an axis, a scan receiver that also orbits about the axis and that receives energy deflected from the core sample when the core sample is inserted within the orbiting scan source and scan receiver. In an example, the core carrier is selectively moveable in an X, Y, and a Z axis. Interlock connectors may be included on the loading cover that are in communication with a controller, so that when the loading cover is in an open position, power to the scan system is blocked. The scan system can be a computerized topography scanner. Optionally, the first and second mobile enclosures each are a trailer portion of a uniquely equipped tractor trailer rig. 
         [0007]    Also disclosed herein is a method of analyzing a core sample which includes providing a first mobile enclosure having a scan system with a loading assembly, disposing the first mobile enclosure proximate a wellbore, disposing a second mobile enclosure adjacent the first mobile enclosure and so that a portion of the loading assembly projects into the second mobile enclosure, disposing the core sample into the second mobile enclosure and inserting the core sample into the loading assembly, and scanning the core sample with the scan system. The core sample can be removed from the scan system so that sections of the core sample can be removed for further analysis to form sample portions. The sections removed from the core sample can be analyzed in a laser based material analyzer. A manipulator can be operated that axially moves the core sample in the scan system. The method can also include orbiting a source of scan energy around the core sample while the core sample is in the scan system, and obtaining scan energy that penetrates and is deflected from the core sample. The method can further involve conducting an initial scan of the core sample, and repositioning the core sample in the scan system based on an analysis of the initial scan. In this example, the step of repositioning the core sample includes adjusting a position of the core sample, such as its elevation, lateral position, or combinations thereof. The method can include identifying an area of interest based on the initial scan for which additional analysis is performed. The step of disposing the first and second mobile enclosures can be to pull the first and second mobile enclosures with a tractor. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]    Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
           [0009]      FIG. 1  is a plan partial sectional view of an example of a system for analyzing a core sample. 
           [0010]      FIG. 2  is an overhead view of an example of a cabinet for shielding radiation and conditioning a scanning unit for a core sample. 
           [0011]      FIG. 3  is an axial sectional view of the cabinet of  FIG. 2  and taken along lines  3 - 3 . 
           [0012]      FIG. 4  is a perspective view of the cabinet of  FIG. 2 . 
           [0013]      FIG. 5  is a perspective view of the cabinet of  FIG. 2  in partial phantom view and an example scanning unit in the cabinet. 
       
    
    
       [0014]    While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF INVENTION 
       [0015]    The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term “about” includes, but is not necessarily limited to, +/−5% of the cited magnitude. In an embodiment, usage of the term “substantially” includes, but is not necessarily limited to, +/−5% of the cited magnitude. 
         [0016]    It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. 
         [0017]    Shown in a plan partial sectional view in  FIG. 1  is one example of a core analysis system  10 , which includes first, second and third mobile enclosures. In the example of  FIG. 1 , the first mobile enclosure is a scan trailer  12 , the second mobile enclosure is a handling trailer  14 , and the third mobile enclosure is an analysis trailer  16 . In one example, each of the enclosures may be part of a tractor trailer and which are movable by a tractor trailer. Schematically illustrated in the scan trailer  12  is a scan system  18 , and substantially all of which is housed within a cabinet  19 . In the illustrated example, cabinet  19  is specially designed to shield any radiation within, generated, inherent, or otherwise, from making its way to outside of the cabinet  19 . Thus, cabinet  19  is in compliance with 21 C.F.R. 1020.40. Further shown in cabinet  19  is a scan source  20 , which in one embodiment includes a device for emitting radiation, such as but not limited to an X-ray, microwave, millimeter wave, etc. A scan receiver  22  is also shown provided within cabinet  19  and combined with scan source  20 , in one example, forms a Computed Tomography (CT) scanner. 
         [0018]    An elongate and cylindrical core sample  24  is shown axially inserted within scan system  18 . Core sample  24  is disposed into scan system  18  through a loading assembly  26 , which is shown coupled to one end of the scan system  18  and projecting through an opening in a side wall of handling trailer  14 . In an example, core sample  24  is taken from a subterranean formation below system  10 , and is retrieved via a wellbore  27  shown adjacent system  10 . Thus the wellbore  27  intersects the subterranean formation. Embodiments exist where the system  10  is “onsite” in the field and where the distance between the wellbore  27  to system  10  can range from less than one hundred yards up to five miles, and any distance between. Accordingly, real time analysis while drilling the wellbore  27  can take place within the system  10 . Feedback from the analysis can be used by the drilling operator to make adjustments or changes to the drilling operation. 
         [0019]    A hatch assembly  28  is schematically illustrated which provides the coupling interface between trailers  12 ,  14  and includes sealing around the loading assembly  26 . While in scan system  18 , core sample  24  rests on a core carrier  30 . In an example, core carrier  30  is fabricated from a material transparent to X-Rays, and can support the load of the core sample  24  with minimum deflection to maintain the resolution of a stationary scanner. Core carrier  30  is part of a manipulator system  31 , which further includes a manipulator arm  32  that telescopingly moves along a manipulator base  34 . As shown, an end of manipulator arm  32  distal from manipulator base  34  couples onto an end of core carrier  30 , so that core carrier is basically cantilevered on an end of the manipulator arm  32 . Manipulator arm  32  is shown in an extended position over manipulator base  34 . Manipulator arm  32  axially moves with respect to manipulator base  34  via a motor  36  shown having a shaft  38  that couples to manipulator arm  32 . In one example, motor  36  is a linear direct current motor. A gear (not shown) on an end of shaft  38  distal from motor  36  engages a gear rack  40  that is provided on manipulator arm  32 . Accordingly, selectively operating motor  36  urges manipulator arm  32 , core carrier  30  and core sample  24  in an axial direction with respect to scan source  20 . Moving manipulator arm  32  into a refracted position onto manipulator base  34  positions the entire length of core sample  24  in scan system  18 , so that all of core sample  24  may be analyzed by the scan system  18 . In one example, the scan source  20  and scan receiver  22  orbit around the core sample  24  and so that when in combination of axial movement of core sample  24  within system  18 , a helical scan is taken of core sample  24 . Further optionally, motor  36 , or additional motors not shown, may manipulate and selectively move manipulator arm vertically and/or laterally to thereby better position core sample  24  into a designated orientation and/or spatial position during the scanning process. 
         [0020]    Further shown in  FIG. 1  are a series of work surfaces  42  provided within handling trailer  14 . In one example of operation, before or after core sample  24  is scanned, it may be broken into sections for further analysis and analyzed on surfaces  42 . Examples of the surfaces  42  include a crusher, sample divider, and mortar grinder. Additional analysis may take place within analysis trailer  16 . Schematically illustrated within analysis trailer  16  are a variety of analysis equipment such as, but not limited to, scanners and spectrometers. One such analysis equipment is a nanotom  44 , which can include a scanning system for scanning the internals of core sample  24 , or parts of the core sample. Further analysis equipment in the analysis trailer  16  may be a laser induced spectroscope  46 , a Raman spectroscope  48 , and near infrared spectroscope  49 . It will be understood that alternate embodiments may include more trailers or fewer trailers. For example, an appropriately sized scan system  18  may allow loading assembly  26  to be in scan trailer  12  without projecting through an opening in the trailer and without a hatch assembly  28 . A further embodiment may provide work surfaces  42  in the same trailer as the analysis equipment, or the analysis equipment may be contained in handling trailer  14 . In yet a further embodiment, scan system  18 , loading assembly  26 , work surfaces  42  and analysis equipment (e.g., nanotom  44 , spectroscopes  46 ,  48 ,  49 , or others) are all contained in one trailer. 
         [0021]    Referring now to  FIG. 2 , shown in an overhead view is an example of the scan system  18  and an upper surface of cabinet  19 . Further illustrated in this example is a conditioning vent  50  on an upper end of the cabinet  19 , where conditioning vent  50  provides a path for airflow and that is used in conditioning the inside of the cabinet  19 , while blocking the leakage of any radiation from cabinet  19 . An advantage of the conditioning vent  50  is that conditioned air at proper temperature and humidity may be injected into the inside of cabinet  19  so that the sensitive devices housed within the cabinet  19  may be maintained in proper operating conditions to ensure normal operating functionality. In an example, operational conditions require maintaining a substantially constant temperature within the cabinet  19 . In one embodiment, the temperature variation in the cabinet  19  is kept of within 2 degrees C. of a designated temperature. An advantage of the device described herein is that the temperature in the cabinet  19  can be maintained within the designated range in spite of substantial air replacement. Air replacement in the cabinet  19 , due to the loading mechanism operation, maintains temperature uniformity across the scanner frame and rotary element. In one example, the volumetric rate of air replacement is at least about 4 m 3 /min. A power distribution panel  52  is shown provided at an aft end of cabinet  19 , and which includes buses (not shown) and other devices for distributing power through cabinet  19  into scan system  18 . A control panel  54  is shown adjacent power distribution panel  52  and includes hardware and software for managing control of the operation of the systems house within cabinet  19 . Projecting outward past the forward end of cabinet  19  is the loading assembly  26  in an open configuration. In the illustrated example, the loading assembly  26  includes a loading cover  56  and loading basin  58 , where the loading cover  56  is shown swung open from a loading basin  58 . As shown the core sample  24  has been inserted into open loading assembly  26  and onto the core carrier  30 . As will be described in more detail below, safety features are included with the system that prevent operation of the manipulator system  31  when the loading assembly  26  is in the open position of  FIG. 2 . 
         [0022]      FIG. 3  shows an example of the cabinet  19  in a sectional view and taken along lines  3 - 3  of  FIG. 2 . This view which is taken along the axial portion of manipulator system  31  shows one example of a wiring track  60 ; which has cross members for organizing the control and power wires needed for use in the scan system  18  and as the manipulator arm  32  axially moves with respect to manipulator base  34 . Wiring track  60  maintains the wires in a designated location and position with use of wiring track  60  during operation of the manipulator system  31 . Further in the example of  FIG. 3  is a shroud  62  shown mounted on an upper end of manipulator system  31  and which covers a portion of the upper end and shields components within the manipulator system  31 . Manipulator base  34  (and thus manipulator arm  32 ) is supported on a vertical mounting pedestal  64 , which has a generally rectangular cross section along its axis, and has a lower end mounted on the floor of cabinet  19 . Shown housed within shroud  62  is a wiring bus  66  which extends axially along the manipulator assembly. 
         [0023]      FIG. 4  provides in perspective view of one example of the cabinet  19  and having hinged panel  68  along its outer surface. As indicated above, the structure of cabinet  19  is in compliance with 21 C.F.R. 1020.40. Thus proper protective shielding and interlocking is provided in the panel  68  and along the hinged interface. An additional safety feature is a door assembly  70  which includes a barrier (not shown) that slides axially across the opening shown at the base of the loading assembly  26  and in a forward wall of cabinet  19 . The barrier thus provides a radiation shield from the inside to the outside of cabinet  19  while still allowing core sample loading in compliance with 21 C.F.R. § 1020.40. 
         [0024]    An example of the manipulator assembly within cabinet  19  is illustrated in perspective view in  FIG. 5 , and where cabinet  19  is shown in a partial phantom view. In this embodiment, a rearward end of manipulator base  34  is supported on a rearward end of cabinet  19 ; manipulator base  34  extends axially away from the rearward wall of cabinet  19  with the manipulator arm  32  axially sliding on manipulator base  34 . Motor  36  is shown oriented generally perpendicular to an axis of manipulator arm  32  and manipulator base  34 , and couples to manipulator arm  32  by shaft  38 . Further illustrated is how the core carrier  30  couples to a mounting plate  72 ; where mounting plate  72  is a generally circular and planar member that mounts on a forward end of manipulator arm  32 . In one embodiment, this member along with an extended tunnel provides the seal that inhibits excessive air flow during the loading process. 
         [0025]    Axial movement, as shown by the double headed arrow A, of core sample  24  is accomplished via motor  36 . X, Y, and Z axes are illustrated to define an example coordinate system for the purposes of reference herein. While not limited to this coordinate system, the axes depict axial movement of any object, such as the core sample  24 , to be along the Z axis, vertical movement to be along the Y axis, and lateral movement to be along the X axis. As indicated above, operation of motor  36  can move core sample  24  along all of these axes. Further shown in  FIG. 5  are curved supports  74 ,  76  that circumscribe manipulator arm  32  and provide a mounting surface for scan source  20  and scan receiver  22 . The combination of the support  74 ,  76  define a gantry  78  that when rotated puts the scan source  20  and scan receiver  22  at an orbiting rotation around the core sample  24  and provides the scanning capabilities of the scan system  18 . As indicated above, the air replacement capabilities provided with cabinet  19  maintains a substantially constant temperature across the gantry  78 . 
         [0026]    Referring back to  FIG. 4 , an interlock connector  80  is shown provided on the loading cover  56  and loading basin  58 . The interlock connectors  80  thus may recognize when the cover  56  is in the open position of  FIG. 4  and in combination with controller  82  may prevent operation of the manipulator assembly. However, the control system associated with the scan system  18  that allows for motion of the manipulator assembly when the cover  56  is in the closed position and interlock connectors are adjacent one another. 
         [0027]    The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. For example, in an embodiment, mounting and shock absorption hardware is provided for securing the components in the core analysis system  10  to maintain their integrity and alignment during transportation in the trailers. The gantry can include reinforced mounting for rotating elements and added adhesive for board mounted components, e.g. integrated circuitry, resistors, capacitors, and the like. A transport locking mechanism can be used to prevent sliding door movement when power is removed, and a locking mechanism can be used on all threaded fasteners. All circuit boards can be mechanically secured to reduce vibration and remove gravity loading on connectors. Relays can be secured to mounting sockets, and expansion loops can be added in all cables and hoses and secured to cabinet walls. High voltage cables can be cushioned, and service door fastening can be added to prevent load on interlock closure. Cooling fan mounting can be reinforced and cooler unit can be secured for shipment. Also, transformer can be set near high voltage generator by mounting to the floor of the cabinet. An advantage of this is a scanned image of the core sample  24  can be produced at a resolution of up to 200 microns. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.