Abstract:
An instrumented perforating gun and associated methods. One aspect provides a recess for placement of instruments on the perforating gun. Another aspect provides methods for perforating and completing a well in a single trip. The present invention also provides an instrumented intergun housing. 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:
BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The present invention relates to the field of well monitoring. More specifically, the invention relates to equipment and methods for real time monitoring of wells during various processes. 
   2. Related Art 
   There is a continuing need to improve the efficiency of producing hydrocarbons and water from wells. One method to improve such efficiency is to provide monitoring of the well so that adjustments may be made to account for the measurements. Other reasons, such as safety, are also factors. Accordingly, there is a continuing need to provide such systems. Likewise, there is a continuing need to improve the placement of well treatments. 
   SUMMARY 
   In general, according to one embodiment, the present invention provides monitoring equipment and methods for use in connection with wells. Another aspect of the invention provides specialized equipment for use in a well. 
   Other features and embodiments will become apparent from the following description, the drawings, and the claims. 

   
     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 a well having a perforating gun with a control line therein, 
       FIG. 2  illustrates a perforating gun in a well having a control line positioned in a passageway of the gun housing. 
       FIG. 3  illustrates a cross sectional view of a perforating gun housing of the present invention showing numerous alternative designs. 
       FIG. 4  is a cross sectional view of a perforating gun housing of the present invention showing numerous alternative designs. 
       FIG. 5  is a side elevational view of a perforating gun housing of the present invention. 
       FIG. 6  shows an alternative embodiment of the present invention. 
       FIG. 7  illustrates another embodiment of the present invention. 
       FIG. 8  is a partial cross sectional view of an alternative embodiment of the present invention. 
       FIGS. 9 through 16  illustrate various other alternative embodiments of the present invention. 
       FIG. 17  shows an intergun housing of the present invention. 
       FIG. 18  illustrates an embodiment of the present invention in which an instrumented perforating gun is provided with a completion. 
       FIG. 19  illustrates an embodiment of the present invention in which the well may be perforated and gravel packed in a single trip into the well. 
       FIG. 20  shows an embodiment of the present invention in which the perforating charges are provided in the casing. 
   

   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. 
   In this description, the terms “up” and “down”; “upward” and downward”; “upstream” and “downstream”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly described some embodiments of the invention. However, when applied to apparatus and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or other relationship as appropriate. 
   One aspect of the present invention is the use of a sensor, such as a fiber optic distributed temperature sensor, in a well to monitor an operation performed in the well, such as a perforating job as well as production from the well. Other aspects comprise the routing of control lines and sensor placement in a perforating gun and associated completions. Yet another aspect of the present invention provides a perforating gun  20  which is instrumented (e.g., with a fiber optic line  24  or an intelligent completions device  26 ). Referring to the attached drawings,  FIG. 1  illustrates a wellbore  10  that has penetrated a subterranean zone that includes a productive formation  14 . The wellbore  10  has a casing  16  that has been cemented in place. The casing  16  has a plurality of perforations  18  formed therein that allow fluid communication between the wellbore  10  and the productive formation  14 . Firing a perforating gun  20  having shaped charges  22  at the desired position in the well forms the perforations. The perforating gun  20  embodiment of  FIG. 1  is a wireline-conveyed perforating gun and is instrumented with a control line  24  extending the length of the gun  20 .  FIG. 1  also illustrates one embodiment in a cased hole although the present invention may be utilized in both cased wells and open hole completions. 
   Although shown with the control line  24  outside the perforating gun  20 , other arrangements are possible as disclosed herein. Note that other embodiments discussed herein will also comprise intelligent completions devices  26  on the perforating gun  20  or the associated completion. 
   Examples of control lines  24  are electrical, hydraulic, fiber optic and combinations of thereof. Note that the communication provided by the control lines  24  may be with downhole controllers rather than with the surface and the telemetry may include wireless devices and other telemetry devices such as inductive couplers and acoustic devices. In addition, the control line itself may comprise an intelligent completions device as in the example of a fiber optic line that provides functionality, such as temperature measurement (as in a distributed temperature system), pressure measurement, sand detection, seismic measurement, and the like. Additionally, the fiber optic line may be used to detect detonation of the guns. 
   In the case of a fiber optic control line, the control line  24  may be formed by any conventional method. In one embodiment of the present invention, a fiber optic control line  24  is formed by wrapping a flat plate around a fiber optic line in a similar manner as that shown in U.S. Pat. No. 5,122,209. In another embodiment, the fiber optic line is installed in the tube by pumping the fiber optic line into a tube (e.g., a hydraulic line) installed in the well. This technique is similar to that shown in U.S. reissue Pat. No. 37,283. Essentially, the fiber optic line  14  is dragged along the conduit  52  by the injection of a fluid at the surface, such as injection of fluid (gas or liquid) by pump  46 . The fluid and induced injection pressure work to drag the fiber optic line  14  along the conduit  52 . 
   Examples of intelligent completions devices  26  that may be used in the connection with the present invention are gauges, sensors, valves, sampling devices, a device used in intelligent or smart well completion, temperature sensors, pressure sensors, flow-control devices, detonation detectors, flow rate measurement devices, oil/water/gas ratio measurement devices, scale detectors, actuators, locks, release mechanisms, equipment sensors (e.g., vibration sensors), sand detection sensors, water detection sensors, data recorders, viscosity sensors, density sensors, bubble point sensors, pH meters, multiphase flow meters, acoustic sand detectors, solid detectors, composition sensors, resistivity array devices and sensors, acoustic devices and sensors, other telemetry devices, near infrared sensors, gamma ray detectors, H 2 S detectors, CO 2  detectors, downhole memory units, downhole controllers, locators, devices to determine the orientation, and other downhole devices. In addition, the control line itself may comprise an intelligent completions device as mentioned above. In one example, the fiber optic line provides a distributed temperature and/or pressure functionality so that the temperature and/or pressure along the length of the fiber optic line may be determined. 
   In an embodiment of  FIG. 1  in which the control line  24  is a fiber optic line, the fiber optic line  24  is connected to a receiver  12  that may be located in the vehicle  13 . Receiver  12  receives the optical signals through the fiber optic line  14 . Receiver  12 , which would typically include a microprocessor and an opto-electronic unit, converts the optical signals back to electrical signals and then delivers the data (the electrical signals) to the user. Delivery to the user can be in the form of graphical display on a computer screen or a print out or the raw data. In another embodiment, receiver  12  is a computer unit, such as laptop computer, that plugs into the fiber optic line  24 . In each embodiment, the receiver  12  processes the optical signals or data to provide the chosen data output to the operator. The processing can include data filtering and analysis to facilitate viewing of the data. 
     FIG. 2  shows a wireline-conveyed perforating gun  20  having a hollow-carrier gun housing  28  and a plurality of shaped charges  22 . The housing  28  has a passageway  30  (control line passageway) formed in the wall thereof with a control line  24  extending through the passageway  30 . The passageway  30  provides protection for the control line  24  and reduces the overall size of the perforating gun  20  when compared to a perforating gun in which the control line  24  is provided on an outer surface of the housing  28 . 
     FIG. 3  is a cross sectional view of the housing  28  showing alternative positions for the passageway  30 , the control line  24 , and the intelligent completions device  26 . The housing  28  has a scallop  32  therein. A scallop  32 , or recess, is a thinned portion of the gun housing  28 . A shaped charge  22  within the housing  28  is aligned with the scallop  32  to minimize the energy loss required to penetrate the housing  28 . The passageway  30 , the control line  24  and the intelligent completions device  26  are spaced from the scallop  32  to prevent damage to the instrumentation (i.e., the control line  24  and intelligent completions device  26 ) when the shaped charges  22  are fired. However, in some applications it may be desirable to fire through a control line  24  or a component of an intelligent completions component  26  to, for example, detect detonation or for other purposes. 
   In one alterative embodiment shown in  FIG. 3 , a control line  24   a  is provided in a passageway  30   a  formed in the outer surface  34  of the housing  28 . In another alternative embodiment shown in  FIG. 3 , a passageway  30   b  is formed in an inner surface  36  of the housing  28 . An intelligent completions device  26  and a control line  24   b  are positioned in the passageway  30   b.    
     FIG. 4  illustrates one alternative embodiment in which a passageway  30   c  formed in the housing outer surface  34  has a control line  24   c  therein. A cover  38  is provided over at least a portion of the length of the passageway  30   c  to maintain the control line  24   c  in the passageway  30   c . The cover  38  may be removeably or fixedly attached to the housing  28  such as by welding, screws, rivets, by snapping into mating grooves in the housing  28 , or by similar means. Alternatively, the perforating gun  20  may comprise one or more cable protectors, restraining elements, clips, adhesive, epoxy, cement, or other materials to keep the control line  24  in the passageway  30 . 
   In one embodiment, shown in  FIG. 3 , a material filler  40  is placed in the passageway  30   a  to mold the control line  24   a  in place. As an example, the material filler  40  may be an epoxy, a gel that sets up, or other similar material. In one embodiment, the control line  24   a  is a fiber optic line that is molded to, or bonded to, the perforating gun  20 . In this way, the stress and/or strain applied to the perforating gun  20  may be detected and measured by the fiber optic line  24   a.    
   Another embodiment shown in  FIG. 4  provides an internal passageway  30   d  within the wall of the housing  28 . A control line  24   d  extends through the internal passageway  30   d.    
     FIG. 4  also shows an embodiment for positioning of an intelligent completions device  26  (e.g., a sensor). As in the embodiment shown, the intelligent completions device  26  may be placed within the wall of the housing  28 . 
     FIG. 5  shows a perforating gun  20  having a housing  28  with a passageway  30  (e.g., a recess, or indentation) formed in the outer surface  34  thereof. Brackets  42 , or clips, secure the control line  24  within the passageway  30 . The passageway  30  and control line  24  are offset from the gun scallops  32 . 
     FIG. 6  illustrates a perforating gun  20  that comprises a housing  28  and a loading tube  44 . The loading tube  44  has a plurality of openings  46  for holding shaped charges  22 . A detonating cord  48  is routed along the back of the shaped charges to fire the shaped charges  22 . The loading tube is placed in the housing  28  with the shaped charges  22  aligned with the housing scallops  32 . One embodiment of the invention illustrated in  FIG. 6  has a control line  24  extending the length of the loading tube  44 . As discussed above with respect to the housing  28 , the control line  24  may extend through a passageway  30  provided on the loading tube  44  (e.g., the interior surface, the exterior surface, or internal to the wall). Another embodiment of  FIG. 6  shows a control line  24  provided on the housing  28  of the perforating gun  20 . 
   Note that, in each of the embodiments discussed herein, the control line  24  may extend the full length of the perforating gun  20  or a portion thereof. Additionally, the control line  24  may extend linearly along the perforating gun  20  or follow an arcuate, or nonlinear, path.  FIG. 6  illustrates a perforating gun  20  having a control line  24  that is routed in a helical path along the perforating gun  20  (both the loading tube embodiment and the housing embodiment). In one embodiment, the control line  24  comprises a fiber optic line that is helically wound about the perforating gun  20  (internal or external to the perforating gun  20 ). In this embodiment, a fiber optic line  24  that comprises a distributed temperature system, or that provides other functionality (e.g., distributed pressure measurement), has an increased resolution. Other paths about the perforating gun  20  that increase the length of the fiber optic line  24  per longitudinal unit of length of perforating gun  20  will also serve to increase the resolution of the functionality provided by the fiber optic line  24 . 
     FIG. 7  discloses another embodiment of the present invention in which a control line  24  is provided adjacent a shaped charge  22 . In the embodiment shown, the shaped charge  22  has a case passageway  52  provided in the shaped charge case  50 . The control line  24  extends through the case passageway  52 . In one embodiment, the control line  24  is a fiber optic line used for shot detection. When the shot fires, the fiber optic line is broken at that point. Light reflected through the fiber optic line indicates the end of the fiber optic line and point at which the line was broken. 
     FIG. 8  shows a wireline-conveyed perforating gun  20  having a control line  24  in the housing  28  and extending the length thereof. 
     FIG. 9  shows an alternative embodiment in which the passageway  30  is routed in an arcuate path (e.g., helical) along the loading tube of a high shot density perforating gun  20 . 
     FIG. 10  is a cross sectional view of a loading tube  44  showing additional alternative embodiments for instrumenting a perforating gun  20 . One embodiment shows a passageway  30  extending along the loading tube  44 . A pair of control lines  24  are routed through the passageway  30 . Another embodiment illustrated in  FIG. 10  provides an intelligent completions device  26  mounted in the wall of the loading tube  44 , such as in a recess provided in the wall, or inside the loading tube  44 . Yet another embodiment shown in  FIG. 10  provides a control line  24  inside the loading tube. 
   Although the aforementioned perforating guns  20  have been described as wireline-conveyed, tubing could also convey the guns  20 . 
     FIGS. 11 through 16  illustrate embodiments of the present invention in which the perforating gun  20  comprises a plurality of shaped charges  22  mounted on a carrier  54 .  FIG. 11  shows a semi-expendable perforating gun  20  having a linear carrier  54 . A control line  24  is mounted to the carrier  54 . Similarly,  FIG. 12  shows a semi-expendable carrier  54  having a plurality of capsule shaped charges  22  mounted thereon and a control line  24  mounted to the carrier  54 . Expendable guns may also be used with the present invention. 
   As used herein, the housing  28 , loading tube  44 , and carrier  54  are generically referred to as a “carrier component” of the perforating gun  20 . 
   In the perforating gun  20  of  FIG. 13 , the carrier  54  is a hollow tube. A control line  24  extends through the carrier  54 , hollow tube. 
     FIGS. 14 and 15  show an alternative embodiment of the present invention used in conjunction with a pivot perforating gun  20 . The pivot gun  20  has a carrier  54  and a pull rod  58 . The shaped charges  22  are mounted to the pull rod  58  in a first position in which the axis of the shaped charges  22  generally pointed along the axis of the perforating gun  20 . Once downhole, the pull rod  58  is caused to move relative to the carrier  54 . A retainer  56  connecting each of the shaped charges to the carrier cause the shaped charges  22  to rotate to a second firing position. The pivot gun  20  may use a variety of other schemes to achieve the pivoting of the shape charges  22 . 
     FIG. 14  illustrates alternative embodiments of the present invention. In one embodiment, the pull rod  58  is a hollow tube having a control line  24  extending therein. In another embodiment, the carrier  54  has a control line  24  mounted therein (see also FIG.  15 ). 
     FIG. 16  shows another embodiment in which the perforating gun  20  comprises a spiral strip carrier  54  in which the carrier  54  is formed into a helical shape. A control line  24  extends along the carrier strip  54 . 
   It should be noted from the above that the shaped charges may be oriented in a variety of phasing patterns as illustrated in the figures. 
     FIG. 17  shows another embodiment of the present invention in which adjacent perforating guns are interconnected by an intergun housing  60 . The intergun housing  60  may contain one or more intelligent completions devices  26  that may be used, for example, to measure reservoir parameters, production characteristics, gun orientation, and gun performance metrics. Additionally, the intelligent completions device  26  in the intergun housing  60  may comprise safety devices that prevent detonation until certain conditions are satisfied (e.g., certain downhole parameters, like pressure, temperature, location, or orientation). Further, the intergun housing may comprise a swivel, a motor, or other device that will facilitate orientation of the perforating gun  20 . Also, the intergun housing  60  may contain other devices that inflate to isolate sections of the wellbore, to shut off zones, or devices that choke back production from sections of the well. 
     FIG. 18  illustrates an alternative embodiment of the present invention in which the perforating guns  20  are run as part of a permanent completion  62 . A completion  62  may comprise a large variety of components and jewelry such as packers, safety valves, sand screens, flow control valves, pumps, intelligent completions devices, and the like. In some circumstances, it is desirable to run the perforating gun  20  with the completion  62  to reduce the number of trips into the well and for other reasons.  FIG. 18  shows a permanent completion  62  having a perforating gun  20  and a control line extending along the completion  62  and the perforating gun  20 . 
     FIG. 19  shows another embodiment of the present invention in which the well is perforated and gravel packed in a single trip into the well. The completion  62  has a perforating gun  20  connected thereto and comprises packers  64 , a sand screen  66 , and a crossover port  68 . The assembly of the completion  62  and the perforating gun is run into the well on a service string  70 . A control line  24  extends along the completion  62  and the perforating gun  20 . Once the perforating gun  20  is aligned with the formation  14 , the perforating gun  20  is fired. Generally, the perforating gun  20  is dropped into the rathole. The completion  62  is then moved into place and the packers  64  are set to isolate the formation  14 . Next, the annulus between the sand screen  66  and the wellbore wall is gravel packed and the service string  70  is removed from the well and replaced with a production tubing. In alternative systems, the gravel pack operation is performed using a through-tubing service tool so that the run-in string may also serve as the production string. 
   However, if a through-tubing gravel pack operation is not used and the service string  70  is replaced with a production tubing, the control line  24  extending above the packer  64  may need to be replaced. Accordingly, in one embodiment, the present invention uses a connector  72  at or near the upper packer  64  that allows the control line  64  to separate so that the upper portion of the control line  24  (the portion above the packer  64 ) may be removed from the wellbore  10 . When the production tubing is placed in the well  10 , a control line attached to the production tubing has a connector  72  that completes the connection downhole of the control line below the upper packer  64  that was previously left in the well  10  with the control line  24  attached to the production tubing. 
   In the embodiment of  FIG. 20 , the perforating gun  20  is a casing-conveyed perforating gun  20 . In this embodiment, the casing  16  has one or more shaped charges  22  mounted thereto. The shaped charges  22  may be mounted in the wall of the casing  16 , inside the casing  16 , or attached to the outside of the casing  16 . A control line  24  extends along the perforating gun  20  (the portion of the casing having the shaped charges  22  therein). In the disclosed embodiment, the control line  24  has a ‘U’ configuration and extends from the surface into the well and returns to the surface. Such a ‘U’ configuration is particularly useful when the control line  24  is a fiber optic line that is blown into the well as previously described. In such a case, the control line may provide redundancy. 
   In some embodiments, the perforating gun  20  uses alternative forms of initiators  74  (see  FIG. 11 ) for activating the shaped charges  22 . As an example, the initiator  74  may be an exploding foil initiator (EFI) which is electrically activated. As used here, “exploding foil initiator” may be of various types, such as exploding foil “flying plate” initiators and exploding foil “bubble activated” initiators. In addition, in further embodiments, exploding bridgewire initiators may also be employed. Such initiators, including EFIs and EBW initiators, may be referred to generally as high-energy bridge-type initiators in which a relatively high current is dumped through a wire or a narrowed section of a foil (both referred to as a bridge) to cause the bridge to vaporize or “explode.” The vaporization or explosion creates energy to cause a flying plate (for the flying plate EFI), a bubble (for the bubble activated EFI), or a shock wave (for the EBW initiator) to detonate an explosive. Some electrical initiators are described in described in commonly assigned copending U.S. Pat. No. 6,385,031, issued May 7, 2002, entitled “Switches for Use in Tools” and U.S. Pat. No. 6,386,108, issued May 14, 2002, entitled “Initiation of Explosive Devices,” which are hereby incorporated by reference. 
   When using an EFI or other electrically activated initiator, it is possible to selectively fire a sequence of perforating strings or even a series of shaped charges. As an example, if a plurality of control devices including a microcontroller and detonator assembly are coupled on a wireline, switches within the perforating gun may be controlled to selectively activate control devices by addressing commands to the control devices in sequence. This allows firing of a sequence of perforating strings or shaped charges in a desired order. Selective activation of a sequence of tool strings is described in commonly assigned copending U.S. Pat. No. 6,283,227, issued Sep. 4, 2001, entitled “Downhole Activation System That Assigns and Retrieves Identifiers” and U.S. patent application Ser. No. 09/404,522, filed Sep. 23, 1999 and published as WO 00/20820 on Apr. 13, 2000, entitled “Detonators for Use with Explosive Devices,” which are hereby incorporated by reference. 
   Accordingly, a perforating gun  20  having electrically activated initiators  74  may be instrumented in the manner previously described. In such a system, the instrumentation (e.g., the fiber optic line  24  or the intelligent completions device  26 ) may provide data during the perforation job. For example, the instrumentation may provide information relating to shot confirmation, pressure, temperature, or flow, among other information, between individual gun  20  or shaped charge  22  detonations. Therefore, in one example, a perforating gun  20  having a plurality of shaped charges  22  and electrically activated initiators is run into a well  10 . The shaped charges  22  are fired in a particular sequence while providing the option of moving the perforating gun  20  between shots, skipping defective charges  22 , as well as other features. The instrumentation  24 ,  26  provides feedback regarding shot confirmation. In another example, the instrumentation  24 ,  26  measures the temperature and pressure in the well following each shot. 
   In another embodiment of the present invention, the instrumentation  24 ,  26  of the perforating gun  20  is used to determine the placement of a fracturing treatment, chemical treatment, cement, or other well treatment by measuring the temperature or other well characteristic during the injection of the fluid into the well. The temperature may be measured during a strip rate test in like manner. In each case remedial action may be taken if the desired results are not achieved (e.g., injecting additional material into the well, performing an additional operation). It should be noted that in one embodiment, a surface pump communicates with a source of material to be placed in the well. The pump pumps the material from the source into the well. Further, the instrumentation  24 ,  26  in the well may be connected to a controller that receives the data from the intelligent completions device and provides an indication of the placement position using that data. In one example, the indication may be a display of the temperature at various positions in the well. In another example, the remedial action comprises firing a perforating gun  20 . In this example, the remedial action may comprise perforating a particular zone again, perforating a longer interval of the wellbore, perforating another zone, or the like. 
   The instrumented perforating gun  20  of the present invention should not be confused with prior perforating guns which have sensors placed above or below the perforating gun. Accordingly, in the present invention the term “instrumented” and the like shall mean that the instrumentation is provided on the perforating gun  20  itself, such as attached to a housing  28 , loading tube  44 , or carrier  54  of the gun  20 , positioned below the uppermost shaped charge  22  of the perforating gun  20  and above the lowermost shaped charge  22 , between shaped charges  22 , or in the substantially the same cross sectional portion of the well  10  as the shaped charges  22 . Thus, the instrument  24 ,  26  is provided on the same shaped charge region of the perforating gun  20  as the shaped charges  22 . 
   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. 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.