Abstract:
The invention generally relates to data transmission in a wellbore. In one aspect, a system for communicating electromagnetic waves in a wellbore is provided. The system includes a sensor equipment package for sensing a parameter in the wellbore and generating an electromagnetic wave. The system further includes an expandable composite tubular having a conducting member and an insulating member. The composite tubular is configured to be expanded from a first diameter to a second larger diameter, wherein the composite tubular in the second larger diameter forms a connection with the wellbore. In another aspect, a method of using a system for communicating electromagnetic waves in a wellbore is provided. In a further aspect, a system for providing electrode contact surfaces between a sensor equipment package and a surrounding tubular disposed in a wellbore is provided.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to data transmission in a wellbore. More particularly, the invention relates to an expandable tubular antenna feed line for electromagnetic communication. 
         [0003]    2. Description of the Related Art 
         [0004]    In the production of an oil well it is important to maintain knowledge of the reservoir pressure in order to maximize the production from the field. For this reason, sensors are installed in the well on completion to provide this data. Unfortunately, over the lifetime of a given well it is highly likely the original sensor will fail, leaving the operator without information. In recent times various groups have begun working on replacement sensors that are wireless in order to avoid the huge costs of re-completion. For instance, a wireless sensor may be placed in a wellbore casing at an appropriate location. On activation, the wireless sensor sends an electromagnetic (“E/M”) signal through the earth-to-surface receiver, thus bringing the sensor&#39;s data to a point where it can be recovered by the user. 
         [0005]    In order to impart an E/M signal, it is necessary to inject time varying current into the earth through the well casing over distances of many meters. A conventional E/M device  50  is illustrated in  FIG. 1 . The E/M device  50  includes a cylindrical body  25  that includes the components of the E/M device  50 . The body  25  is coupled to production tubing  20  by slips  31  and  32 , which when energized, protrude radially out of the body  25  and wedge the E/M device  50  in place within the production tubing  20 . The slips  31 ,  32  also serve as the current injection points for the E/M signal which is created in an electronics package  35  of the E/M device  50 . The total length of the E/M device  50  is dominated by the spacing required between the slips  31 ,  32  in the body  25 . Modeling suggests the minimum spacing L 1  is 33 feet (10 meters). The length of the E/M device  50  makes the entire tool unwieldy to transport and handle during well intervention operations. The E/M device  50  further includes a sensor and battery pack  34 , and a power generation member  33 , whose combined length may be on the order of 3.3 feet (1 meter). Once installed the E/M device  50  is a self-powered device that is designed to measure a relevant reservoir parameter and relay the data to the surface. It is also a requirement that a passageway exist through the E/M device  50  to allow the flow of wellbore fluids  40  to proceed through the E/M device  50 . The conventional E/M device tends to occupy a large part of the wellbore cross-section and, as such, presents an impediment to flow. Therefore, there is a need for another E/M device that minimizes the restriction of the wellbore cross-section. 
       SUMMARY OF THE INVENTION 
       [0006]    This invention generally relates to data transmission in a wellbore. In one aspect, a system for communicating electromagnetic waves in a wellbore is provided. The system includes a sensor equipment package for sensing a parameter in the wellbore and generating an electromagnetic wave. The system further includes an expandable composite tubular having a conducting member and an insulating member. The composite tubular is configured to be expanded from a first diameter to a second larger diameter, wherein a portion of the composite tubular in the second larger diameter is used as current injection points for the electromagnetic wave generated by the sensor equipment package. 
         [0007]    In another aspect, a method of using a system for communicating electromagnetic waves in a wellbore is provided. The method includes the step of positioning a composite tubular in the wellbore. The method further includes the step of expanding the composite tubular from a first diameter to a second larger diameter such that the composite tubular engages the wellbore. The method also includes the step of coupling a sensor equipment package to the composite tubular. Furthermore, the method includes the step of sensing a parameter in the wellbore. Additionally, the method includes the step of generating an electromagnetic wave that is transmitted through current injection points in the expanded composite tubular. 
         [0008]    In a further aspect, a system for providing electrode contact surfaces between a sensor equipment package and a surrounding tubular disposed in a wellbore is provided. The system includes a conducting tubular. The system further includes an insulating tubular bonded to the conducting tubular. The conducting tubular is disposed within the insulating tubular such that a portion of the conducting tubular extends from an end of the insulating tubular at one end and a portion of the insulating tubular extends from the conducting tubular at an opposite end. Additionally, the system includes an electrode ring disposed adjacent the portion of the insulating tubular that extends from the conducting tubular. The tubulars and the electrode ring are configured to be expanded from a first diameter to a second larger diameter to form electrode contact surfaces that are used between the sensor equipment package and the surrounding tubular. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0010]      FIG. 1  is a view illustrating a conventional E/M device. 
           [0011]      FIG. 2  is a view illustrating an E/M communication device disposed within a wellbore. 
           [0012]      FIGS. 3A and 3B  are views illustrating the placement of a composite tubular within a tubing member. 
           [0013]      FIGS. 4A and 4B  are views illustrating the composite tubular. 
           [0014]      FIG. 5  is a view illustrating a sensor equipment package disposed in the composite tubular. 
           [0015]      FIG. 6  is a view illustrating the E/M communication device disposed in the tubing. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    The present invention generally relates to an expandable tubular antenna feed line for electromagnetic communication. The present invention is designed to create a wireless “antenna” system in the well to enable E/M data communication to the surface. The invention makes use of expandable tubular technology to make remote electrical contact with a casing in a wellbore without occupying much of the cross-sectional area of the well. To better understand the novelty of the E/M communication device of the present invention and the methods of use thereof, reference is hereafter made to the accompanying drawings. 
         [0017]      FIG. 2  is a view illustrating an E/M communication device  100  of the present invention disposed within a casing  10  of a wellbore. The device  100  is placed in the wellbore casing  10  at an appropriate location. On activation, the device  100  sends an E/M signal  55  through the earth to a surface receiver  50 . The downhole data may be recovered from the surface receiver  50  by a user. The E/M communication device  100  generally includes a sensor equipment package that is coupled to an expandable composite tubular. 
         [0018]      FIGS. 3A and 3B  are views illustrating the placement of a composite tubular  105  within a tubing  20  (e.g., production tubing) disposed within the casing (not shown). As will be described herein, the composite tubular  105  of the device  100  will be used with a sensor equipment package. The composite tubular  105  includes a conducting member  110  that is made from a material that is capable of being an electrical conductor, such as copper, gold, or aluminum. The composite tubular  105  further includes an insulating member  115  that is made from a material that is capable of being an electrical insulator, such as Teflon or a fluoroelastomer. The composite tubular  105  also includes an electrode band  130  that is attached to an end portion of the insulating member  115  ( FIG. 5 ). The electrode band  130  is made from a material that is capable of being an electrical conductor, such as copper, gold, or aluminum. 
         [0019]    The composite tubular  105  and an expansion device  80  may be lowered into the tubing  20  via a work string  75 . In one embodiment, the composite tubular  105  is attached to the expansion device  80  by a shearable connection (not shown). After the composite tubular  105  is positioned within the tubing  20 , the shearable connection may be released and the expansion device  80  may move relative to the composite tubular  105 . The expansion device  80  may be urged through the composite tubular  105  to enlarge the composite tubular  105  from a first diameter ( FIG. 4A ) to a second larger diameter ( FIG. 4B ). As shown, the composite tubular  105  is in contact with the surrounding tubing  20 . Once installed, the composite tubular  105  provides an insulated conductor the length of the device  100 . 
         [0020]      FIGS. 4A and 4B  are views illustrating the composite tubular  105 . In the initial state, the composite tubular  105  is formed in a cylindrical shape to the length and diameter as required for the specific installation. The outer diameter of the unexpanded composite tubular  105  must be sufficiently smaller than the inner diameter of the tubular  20  in order to be inserted in the wellbore. After expansion, the composite tubular  105  looks as shown in  FIG. 4B  and is uniformly expanded to contact the tubular wall  20 . In another embodiment, the composite tubular  105  is corrugated, such that the outer diameter of the composite tubular  105  is non-uniform. 
         [0021]      FIG. 5  is a view illustrating a sensor equipment package  125  disposed in the composite tubular  105 . After the composite tubular  105  is expanded into contact with the surrounding tubing  20 , the expansion device is removed from the composite tubular  105 , and the sensor equipment package  125  is coupled to the composite tubular  105 . This is a two-step process. In the first step, the composite tubular  105  is lowered and expanded into the tubing  20 . In the second step, the sensor equipment package  125  is positioned within the expanded composite tubular  105 . In another embodiment, the expansion of the composite tubular  105  and the placement of the sensor equipment package  125  may be done in a single-step process. In the single-step process, the composite tubular  105  and the sensor equipment package  125  are lowered together. The sensor equipment package  125  includes an expansion cone (not shown) that is used to expand the composite tubular  105  from the first diameter to the second larger diameter. Thereafter, the sensor equipment package  125  (and the expansion cone) remains within the expanded composite tubular  105 . In a further embodiment of the single-step process, the composite tubular  105 , the sensor equipment package  125  and a removable expansion device (not shown) are lowered together on the workstring. The removable expansion device expands the composite tubular  105  to enlarge the composite tubular  105  from the first diameter to the second larger diameter, and then the sensor equipment package  125  is positioned within the composite tubular  105 . Thereafter, the removable expansion device is removed from the wellbore, while the composite tubular  105  and the sensor equipment package  125  remain in the wellbore. 
         [0022]    As shown in  FIG. 5 , the conducting member  110  is designed to overhang the insulating member  115  at one end of the composite tubular  105 , thereby providing a contact directly to the tubing  20 . At the other end of the composite tubular  105 , the insulating member  115  extends beyond the conducting member  110 , thereby insulating the conducting member  110  from the tubing  20  and an electrode band  130 . Once expanded, the composite tubular  105  provides two electrode contact surfaces to the tubing  20  separated by the length of expanded composite tubular  105 . 
         [0023]    At the points where the conducting member  110  and the electrode band  130  contact the wall of the tubing  20 , there may be placed sharp slip-like grooves (not shown) to insure the contact with the tubing  20  is of low resistance. Such grooves or slips are configured to cut into the surface of the wall of the tubing  20  to expose good metal below any corrosion or dirt which may be present. Additionally, in one embodiment, the conducting member  110  and electrode band  130  (and the grooves or slips) are plated with gold to reduce corrosion while disposed in the wellbore. 
         [0024]    Once the composite tubular  105  is installed and expanded in the wellbore, the sensor equipment package  125  can be lowered into the well. Once the sensor equipment package  125  is located within the composite tubular  105 , slips  135 ,  140  (or deployable contacts) are activated to engage the conducting portions of the expanded composite tubular  105 , contacting the upstream electrode band  130  and the conducting member  110 . The slip arrangement gives an E/M generator (not shown) within the sensor equipment package  125  access to current injection points at the distal ends of the expanded composite tubular  105 . 
         [0025]      FIG. 6  is a view illustrating the device  100  disposed in the tubing  20 . As shown, the device  100  further includes a sensor and battery pack  150  and a turbine  155 . As shown, the device  100  is a self-powered instrument device that is equipped with the turbine  155 . The turbine is configured to be powered by flow  160  in the wellbore. The device  100  comprsing the sensor equipment package  125  coupled to the composite tubular  105  by expanding internal slips into contact with the electrode band  130  and the conducting member  110 . The benefit of the arrangement shown in  FIG. 6  is that the total well obstruction has been reduced from in excess of 33 feet (10 meters) as in the conventional E/M device  50  (see L 1  on  FIG. 1 ) to less than 6.6 feet (2 meters) in the device  100  (see L 2  on  FIG. 6 ), thereby greatly reducing the pressure loss in the well due to its presence. 
         [0026]    In another aspect, the setting tool used to deliver the instrument package or the instrument package itself could also serve as the expansion device for the composite tubular. In this manner the entire system could be installed in a well in a single pass as set forth herein, and the instrument package would reside at the downstream end of the composite tubular after installation, which is the reverse of what is shown in  FIG. 6 . 
         [0027]    In a further aspect, the composite tubular is a pre-assembled composite of insulating outer material and conducting inner shell. The insulating material is chosen for properties that will insure complete insulating coverage after expansion of the inner shell. The invention also provides for penetrating ridges imbedded in the conductor at the distal end to insure low resistivity contact is made on expansion. 
         [0028]    In an additional aspect, a system and method of providing an insulated feed line allows remote placement of a current injection point. The invention is for the placement of current injection electrodes for creating E/M signals in the earth adjacent to a borehole. The invention may however be used to provide an insulated pathway along a borehole for any purpose. 
         [0029]    In a further aspect, the object of this invention is to provide an alternative method of creating injection points along the production tubing, thereby shortening the overall equipment package and reducing the resistance to flow. 
         [0030]    Although the descriptions above contain many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this present invention. Further, it should be understood that the invention is not to be unduly limited to the foregoing which has been set forth for illustrative purposes. Various modifications and alternatives will be apparent to those skilled in the art without departing from the true scope of the invention, as defined in the following claims. While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover those changes and modifications which fall within the true spirit and scope of the present invention. 
         [0031]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.