Abstract:
One aspect of the present invention is a system and method to measure a pressure or other measurement at a source (e.g. a hydraulic power supply) and in or near a downhole tool and compare the measurements to verify that, for example, the supply is reaching the tool. Another aspect of the present invention is a system and method in which a gauge is positioned within a packer. Yet another aspect of the invention relates to a gauge that communicates with the setting chamber of a packer as well as related methods. Other aspects and features of the system and method are also described. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Description:
The following is based upon and claims priority to U.S. Provisional Application Ser. No. 60/521,934, filed Jul. 22, 2004 and U.S. Provisional Application Ser. No. 60/522,023, filed Aug. 3, 2004. 

   BACKGROUND OF THE INVENTION 
   Field of Invention  
   The present invention relates to the field of measurement. More specifically, the invention relates to a device and method for taking downhole measurements as well as related systems, methods, and devices. 
   SUMMARY 
   One aspect of the present invention is a system and method to measure a pressure or other measurement at a source (e.g. a hydraulic power supply) and in or near a downhole tool and compare the measurements to verify that, for example, the supply is reaching the tool. Another aspect of the present is a system and method in which a gauge is positioned within a packer. Yet another aspect of the invention relates to a gauge that communicates with the setting chamber of a packer as well as related methods. Other aspects and features of the system and method are further discussed in the detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The manner in which these objectives and other desirable characteristics can be obtained is explained in the following description and attached drawings in which: 
       FIG. 1  illustrates an embodiment of the present invention including a downhole tool, a supply, and alternate pressure measurements. 
       FIG. 2  shows an alternative embodiment of the present invention. 
       FIG. 3  illustrates an embodiment of the present invention deployed in a well. 
       FIG. 4  illustrates a subsection of  FIG. 3 . 
       FIG. 5  is a schematic of the present invention and the embodiment of  FIG. 3 . 
       FIG. 6  illustrates another embodiment of the present invention in which a gauge is incorporated into a packer. 
       FIGS. 7 and 8  illustrate yet another embodiment of the present invention in which a gauge is provided above a packer and communicates with an interior of the packer. 
   

   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. 
   DETAILED DESCRIPTION OF THE INVENTION 
   In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
   The present invention relates to various apparatuses, systems and methods for measuring well functions. One aspect of the present invention relates to a measurement method comprising measuring a characteristic of a supply, measuring the characteristic in or near a downhole tool and spaced from the supply measurement, and comparing the measurements (e.g., using a surface or downhole controller, computer, or circuitry). Another aspect of the present invention relates to a measurement system, comprising a first sensor adapted to measure a characteristic of a supply, a second sensor adapted to measure the characteristic in or near a downhole tool, the second sensor measuring the characteristic at a point that is spaced from the supply measurement. Other aspects of the present invention, which are further explained below, relate to verifying downhole functions using the measurements, improving feedback, providing instrumentation to downhole equipment without incorporating the gauges within the equipment itself and other methods, systems, and apparatuses. Further aspects of the present invention relate to placement of gauges in or near packers as well as related systems and methods. 
   As an example,  FIG. 1  illustrates a well tool  10  attached to a conduit  12 . The tool has a hydraulic chamber  14 , such as a setting chamber, therein. The hydraulic chamber  14  may be, for example, an area within the tool  10  into which hydraulic fluid is supplied to actuate the tool  10 . A remote source  16  supplies hydraulic fluid to the well tool  10  (i.e., the hydraulic chamber  14 ) via a hydraulic control line  18 . The source  16  may be located at the surface or downhole. A first sensor  20  measures a characteristic at the source  16 . For example, the sensor  20  may measure the pressure of the hydraulic fluid at the source  16  that is supplied to the control line  18 . A second sensor  22  measures the characteristic in the control line  18  at a position near the tool  10  and spaced from the first sensor measurement. If applied to the example mentioned above, the second sensor may measure the pressure in the control line  18  proximal the well tool  10 .  FIG. 1  also shows an alternative design in which the alternative second sensor  24  measures the characteristic in the tool  10  (e.g., in the hydraulic chamber  14 ). The alternative second sensor  24  may be external to the tool  10  in which case the sensor  24  is hydraulically and functionally plumbed to measure the pressure in the tool  10 . Alternatively, the sensor  10  is positioned within the tool  10 . The sensors  22  and  24  are described as alternatives and only one may be used, although alternative arrangements may use both sensors  22  and  24 . 
   In use, the measurements from the first sensor  20  and the second sensor  22  and/or alternative second sensor  24  are compared. The comparison may reveal whether the supplied fluid is actually reaching the tool. For example, if the control line  18  is blocked the measurements between the first sensor  20  and the second sensor  22  (or alternative second sensor  24 ) will be different. If these values are substantially the same, the operator can determine that the source is actually reaching the tool. 
     FIG. 2  illustrates another aspect of the present invention in which the two sensors  20  and  22  of  FIG. 1  are replaced with a differential sensor  26  (e.g., a differential pressure gauge). The measurement of the differential sensor  26  can likewise indicate potential problems in and provide confirmation of whether the supply is reaching the tool  10 . The differential sensor  26  is shown measuring the characteristic in the control line  18  near the tool  10 . However, as in the embodiment of  FIG. 1 , the sensor could alternatively measure the characteristic within the tool  10 . 
     FIG. 3  illustrates one potential application of the present invention and a system and method of the present invention applied in a multizone well  30 . A lower completion  32  for producing a lower zone of the well  30  has a sand screen  34 , packer  36 , and other conventional completion equipment. An isolation system  40  above the lower completion  32  comprises a packer  42  and an isolation valve  44 . The isolation valve  44  selectively isolates the lower completion  32  when closed. An upper completion  50  (see also  FIGS. 4 and 5 ) for producing an upper zone of the well  30  comprises, from top to bottom, a hydraulically set packer  52  (e.g., a production packer or gravel pack packer), a gauge mandrel  54 , an annular control valve  56 , an in-line control valve  58  and a lower seal assembly  60 . The lower seal assembly  60  stabs into the isolation assembly  40  to hydraulically couple the upper completion  50  to the isolation assembly  40 . Thereby, the in-line control valve  58  is in fluid communication with the lower completion  32  and may be used to control production from the lower completion  32 . The annular control valve  56  of the upper completion  50  may be used to control production from the upper formation. The gauge mandrel  54  houses numerous pressure gauges  62 . 
   After the upper completion  50  is placed in the well  30  the annular valve  56  and the in-line valve  58  are both closed and pressure is applied inside the production tubing  64  to test the tubing  64 . The packer  52  is then set. 
   In order to set the packer  52  of the upper completion  50 , the annular valve  56  is closed and the in-line valve  58  is opened. The isolation valve  44  is closed and the pressure in the tubing  64  is increased to a pressure sufficient to set the packer  52 . A packer setting line  66  extends from the packer  52  and communicates with the tubing  64  at a position below the in-line valve  58 . In this example, the pressure in the tubing  64  acts as the source of pressurized hydraulic fluid used to set the packer. This porting of the packer  52  is necessary to prevent setting of the packer  52  during the previously mentioned pressure test of the tubing  64 . 
   One of the pressure gauges  62   a  communicates with the interior of the tubing  64 , the source of the pressurized setting fluid, via a gauge ‘snorkel’ line  68 . The snorkel line  68  communicates with the tubing  64  at a position below the in-line valve  58  and, thereby, measures the pressure of the source of pressurized hydraulic fluid used to set the packer. This pressure gauge  62   a  provides important continuing data about the produced fluid and well operation. 
   It is often desirable to have a second redundant pressure gauge  62   b  or sensor that measures the same well characteristic to, for example, verify the measurement of the first gauge, provide the ability to average the measurements, and allow for continued measurement in the event of the failure of one of the gauges. Typically, the primary gauge  62   a  and the back-up gauge  62   b  are ported via independent snorkel lines  68  to the substantially same portions of the well. However, in the present invention, the ‘redundant’ pressure gauge  62   b  is plumbed to and fluidically communicates with the packer setting line  66  via connecting line  70 . Therefore, the redundant pressure gauge  62   b  measures the pressure in the packer setting line  66  near the packer  52  at a location that is spaced from the location of the measurement of the first pressure gauge  62   a . Both pressure gauges  62   a  and  62   b  remain in fluid communication with the production tubing  64  at a point below the in-line valve  58  and provide the important continuing data about the produced fluid and well operation at this portion of the well. However, by fluidically connecting the back-up gauge  62   b , the operator can determine whether a blockage has occurred in packer setting line  66  between the inlet  72  and the connection point  74  to the connecting line  70 . Positioning the connection point  74  near the packer  52  helps to verify that the pressurized fluid is actually reaching the packer  52 . In addition, using the connection line  70  attached to the packer setting line  66  can reduce the amount of hydraulic line used in the completion. Additionally, due to system used in the present invention, the pressure gauge  62   b  provides a dual function of measuring the pressure in the well and helping to verify that the packer  52  is set. The added feature is provided at a minimal incremental cost. In some cases, for example when operating in a high debris environment, the packer setting line  66  may become plugged. If the operator quantifiably knows that pressure either has or has not reached the packer setting chamber, successful mitigation measures may be more easily deployed. 
   Note that as mentioned above in connection with  FIG. 1 , the connection point  74  may be moved to within the packer setting chambers to validate the actual pressure delivered to the packer  52 . Additionally, as discussed above in connection with  FIG. 2 , the two pressure gauges may be replaced with a differential pressure gauge to provide the verification. 
     FIG. 6  illustrates an embodiment of the present invention in which a gauge  80  is positioned within a packer  82  potentially eliminating the need for a separate gauge mandrel. Note that the previous description and  FIGS. 3-5  show a separate gauge mandrel  54 , located below the packer  52 , which houses the gauges  62 . The present embodiment may reduce the overall completion cost for some completions by eliminating the gauge mandrel  54 . The gauge  80  is mounted within the setting chamber  84  of the packer  82  in the embodiment shown in the figure, although the gauge  80 , may also be mounted within other portions of the packer  82 . 
   In  FIG. 6 , the packer  82  has a mandrel  86  on which are slips  88 , elements  90 , and setting pistons  92 . Pressurized fluid applied to the setting chamber  84  hydraulically actuates the pistons  92  setting the packer  82 . In alternate designs, the pressurized fluid may be applied to the packer  82  by either a hydraulic control line  94 , which extends below the packer  82  as discussed previously or which extend to the surface (not shown), or via ports in the packer  82  that communicate with the tubing (the discussion of  FIG. 7  will describe such a packer). 
   Typically, the space available in a packer  82  outside the mandrel  86  (e.g., in the setting chamber  84 ) is insufficient to house a gauge  80  such as a pressure gauge. However, with the advent of MEMS (“Micro-Electro-Mechanical Systems”) and nanotechnology it is possible and will increasingly become possible to make very small gauges. These gauges  82  may be placed within existing packers or the packers may be only slightly modified to accommodate the small gauges. In addition, other customized gauges may be employed. 
   The embodiment illustrated in  FIG. 6  shows a packer that has two gauges  80  in the setting chamber  84 . Control line provides power and telemetry for the gauges  80 . One of the gauges  80   a  communicates with the central passageway  98  of the mandrel  86  via port  100  and, thereby, measures the tubing pressure. The second gauge  80   b  communicates with an exterior of the packer  82  and, thereby, measures the annulus pressure. Additional gauges  80  may be supplied and the gauges may be positioned and designed to measure the pressure at different places within the well. For example, control lines may run from the packer to various points in the well to supply the needed communication. Also, gauges and sensors other than pressure gauges may be used to measure other well parameters, such as temperature, flow, and the like. The gauge  80  could additionally be designed to measure the pressure within the setting chamber  84 . As discussed previously, measuring the pressure in the setting chamber  84  provides a confirmation that the pressure in the setting chamber  84  reached the required setting pressure for setting the packer  82 . In addition, the pressure gauge  80  positioned in the setting chamber  84  and adapted to measure the pressure in the setting chamber  84  may also measure and provide continuing data about the pressure via the pressure setting ports or control lines (e.g., snorkel lines). Thus, a pressure gauge  80  so mounted provides the dual purpose of confirming packer setting and providing continuing pressure data. 
   By placing the gauges  80  in the packer  82 , the gauges  80  are very well protected while eliminating the need for a separate mandrel. Eliminating the mandrel  54  also may eliminate the need for timed threads or other special alignment between the packer  80  and a mandrel  54 . In addition, the total length of the completion may be reduced, the cost of equipment and the cost of completion assembly may be reduced, and the electrical connections and gauges  80  can be tested at the “shop” rather than at the well site, or downhole. The present invention provides other advantages as well. 
     FIGS. 7 and 8  illustrate yet another embodiment of the present invention in which a gauge  80  is provided above a packer  82  and communicates with an interior of the packer  80 . The embodiment of  FIGS. 7 and 8  show a pressure gauge  80  that communicates with the interior setting chamber  84  of the packer  82  via a passageway  102 , which in turn communicates with the interior central passageway  98  of the packer  82  via radial setting ports  104 . In this way, the pressure gauge  82  can measure the pressure in the setting chamber  84  to confirm the setting pressure as well as the pressure in the central passageway  98  to measure the tubing pressure and provide continuing pressure information about the production and the well. 
   The present invention may be used with any type of packer.  FIG. 7  shows the present invention implemented in one type of hydraulic packer  82 . For a detailed description of a similar packer, please refer to U.S. Patent Application Publication No. U.S. 2004/0026092 A1. In general, the packer  82  shown has a mandrel  86  on which are slips  88 , elements  90 , and setting pistons  92 . Setting ports  104  extend radially through the mandrel  86  providing fluid communication between an interior central passageway  98  of the mandrel  86  to a packer setting chamber  84  in the packer  82 . The setting ports  104  communicate the tubing pressure through the mandrel  86  into the setting chamber  84  of the packer  82 . 
   The packer  82  shown is hydraulically actuated by fluid pressure that is applied through a central passageway  98  of the mandrel  86 . The pressure of the fluid in the central passageway  98  is increased to actuate the pistons  92  to set the packer  82 . 
   The figures show the gauge  80  connected to the top of the packer  82 . This type of connection eliminates the need for an additional gauge mandrel  54 . In alternative designs, the gauge  80  may be placed further above the packer  82  with a conduit (e.g., snorkel line) connecting the gauge  80  to the packer  82 . 
   As mentioned above, because the gauge  80  measures the pressure of the setting chamber  84 , it is possible to follow the setting sequences of the packer  82 . The sensor also provides the dual function of also measuring the tubing pressure in the packer  82  shown. Note that if the packer  82  is set by annulus pressure or control line pressure, a gauge communicating with the setting chamber  84  measures the pressure from that pressure source  16 . In addition, the invention of  FIGS. 7 and 8 , as well as that of  FIG. 6 , may be implemented in other types of packers, such as mechanically set packers. The packer  82  may be ported in a variety of ways and additional passageways or ports may be provided to allow measurement at other points in the well (e.g., ports to the annulus, snorkel lines to other locations or equipment in the well, passageways in a mechanically-set packer, etc). 
   Furthermore, the inventions of  FIGS. 6-8  may be used in the confirmation system previously discussed. Specifically, in both of the inventions of FIGS.  6  and  7 - 8 , a pressure gauge  80  may be used to measure the pressure in the setting chamber  84 . The pressure data from the gauge  80  may be compared to a measurement at the supply to confirm that the source  16  is reaching the setting chamber. In addition, additional gauges  80  in the packer  82  (e.g., in the embodiment of  FIG. 6 ) may be ported to communicate with the source  16  to provide the desired measurements while potentially eliminating the need for a gauge mandrel  54 . These dual gauges  80  may also provide the desired redundancy discussed above depending upon the porting of the gauges. 
   Note that in the above embodiments, the gauge is ported or positioned to measure the actual or direct characteristic as opposed to an indirect characteristic. For example, the gauge  80  in  FIG. 7  is directly ported to the setting chamber  84  of the packer  82  and thus provides a direct measurement. This is opposed to an indirect measurement in which a tubing pressure measurement remotely located or not interior to the packer  82  is made to show setting chamber pressure. 
   The above discussion has focused primarily on the use of pressure gauges in packers, although some other measurements are mentioned. It should be noted, however, that the present invention may be incorporate other types of gauges and sensors (e.g., in the packer of as shown in  FIG. 6  or to compare measurements from two sensors, etc.). For example, the present invention may use temperature sensors, flow rate measurement devices, oil/water/gas ratio measurement devices, scale detectors, equipment sensors (e.g., vibration sensors), sand detection sensors, water detection sensors, viscosity sensors, density sensors, bubble point sensors, pH meters, multiphase flow meters, acoustic detectors, solid detectors, composition sensors, resistivity array devices and sensors, acoustic devices and sensors, other telemetry devices, near infrared sensors, gamma ray detectors, H2S detectors, CO2 detectors, downhole memory units, downhole controllers, locators, strain gauges, pressure transducers, and the like. 
   Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. For example, much of the description contained here deals with pressure measurement and pressure sensors, in other applications of the present invention the sensors may be designed to measure temperature, flow, sand detection, water detection, or other properties or characteristics. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.