Abstract:
A downhole perforating device includes: a perforating gun having incorporated therein at least two shape charges; an elongated detonating cord incorporated with the perforating gun and extending along a length of the perforating gun, the detonating cord including: a flexible jacket surrounding an explosive; and a communication medium extending within or attached onto the flexible jacket layer.

Description:
TECHNICAL FIELD 
   Embodiments in the present application relate to the field of explosive detonating cords, and more particularly to detonating cords in connection with downhole perforating of a hydrocarbon well. 
   BACKGROUND 
   A hydrocarbon well is typically lined by a well casing. The well casing is normally made of metal and is essentially impervious to well fluids. Thus, in order to harvest hydrocarbons, holes are created in the casing to allow well fluids to flow from a formation into the inside of the casing. Normally, the holes are created by detonating shape charges thereby propelling a mass though the well casing and into the surrounding formation. The holes in the well casing and the formation encourage flow of well fluid. 
   A perforating gun is used to perforate the casing and the formation. A perforating gun typically has a number of shape charges. The shape charges can be held in place by a sleeve that is located within an outer tube. Plural perforating guns can be connected in a string to create a perforating gun string. 
   The present application discusses some embodiments that address a number of issues associated therewith. 
   SUMMARY 
   A non-limiting embodiment is directed toward a downhole perforating device, comprising: a perforating gun having incorporated therein at least two shape charges; an elongated detonating cord incorporated with the perforating gun and extending along a length of the perforating gun, the detonating cord comprising: a flexible jacket surrounding an explosive; and a communication medium extending within or attached onto the flexible jacket layer. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1  is a cross-section of an embodiment. 
       FIG. 2  is a cross-section of an embodiment. 
       FIG. 3  is a cross-section of an embodiment. 
       FIG. 4  is an isometric of the embodiment shown in  FIG. 1 . 
       FIG. 5  is an isometric of an embodiment. 
       FIG. 6  is an isometric of an embodiment. 
   

   DETAILED DESCRIPTION 
   In the following description, numerous details are set forth to provide an understanding of certain embodiments of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without many of these details and that numerous variations or modifications from the described embodiments are possible. 
   As used here, the terms “uphole” and “downhole”, “above” and “below”; “up” and “down”; “upper” and “lower”; “upwardly” and “downwardly”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments of the invention. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left, a right, a right to left, or a diagonal relationship as appropriate. 
   As noted above, perforating guns typically include shape charges. The shape charges can be detonated by way of a detonating cord. The detonating cord contains an explosive that extends longitudinally along the cord. Typically the explosive forms a core of the cord. The explosive could also have a hollow cross sectional shape, or be located within the cord in other ways. 
   The present application describes a detonating cord that includes an explosive part and a communicating medium, the explosive part and the communication medium being incorporated together in the cord, e.g. embedded in a flexible jacket. That configuration provides increased resilience to downhole environments and forces experienced during assembly of the perforating gun and placement of the perforating gun downhole, e.g., potential pulling, pressing and crimping of the cord. Various embodiments of that idea are described herein. 
     FIG. 1  is a cross-sectional view of an embodiment of a detonating cord  1  according to the present application.  FIG. 4  is an isometric view of the embodiment shown in  FIG. 1 . The detonating cord  1  has an explosive  100  that extends along a longitudinal path. The cord  1  also includes a communication medium  300  that can communicate signals and information. The communication medium  300  can be made of anything that adequately transmits signals/information, such as: metal wire, woven metal, fiber-optic cable, or a pressure conduit. A metal sheath could surround the explosive  100 , and could be separated from the core  100  by an insulating layer, e.g., a woven fabric layer  200 . Examples of materials that make up the communication medium  300  are: insulated or non-insulated wire, fiber optics, pressure tube, carbon conductor, etc. A jacket layer surrounds the explosive part  100  and the communication medium  300  so that the explosive part  100  and the communication medium  300  are essentially embedded within, or attached to, the flexible jacket  400 . Examples of flexible jacket material that can be used are: elastomers, lead, soft metals, plastics, fibrous materials, fabric, etc. If the flexible jacket  400  is formed of a conductive material, e.g. lead or soft metal, the flexible jacket  400  can be used to as a communication medium. 
   In the figures, the communication medium  300  and the explosive part  100  are shown as being adjacent to one another. The cloth layer  200  can wrap around the explosive part  100 . The cloth layer  200  can be woven. The communication medium  300  can run essentially parallel with the explosive part  100 . The communication medium  300  can also be wound around the explosive part  100 , e.g., in a helical manner as shown in the  FIG. 5 . There can be more than one communication medium  300 , as shown in  FIG. 6 . There is not a limit to the number of communication mediums  300  that can be used. The communication medium could also be embedded within the explosive  100 . The communication medium  300  could be a woven metallic sheath surrounding the explosive  100 . 
     FIG. 2  is a cross-section schematic of an embodiment of a perforating gun  500  according to the present application. A series of shape charges  600  are arranged on/around a sleeve  510 . The sleeve  510  supports the shape charges  600 . The shape charges  600  can be configured in many ways, e.g., helically, staggered, opposite from each other, etc. The detonating cord  1  extends within the perforating gun  600  and connects to the shape charges  600 . The detonating cord  1  can connect to a controller  530 . The controller can have integrated thereto, or be connected with, a sensor device  540 . The sensor device  540  can be placed within the perforating gun  600  as shown. Also, sensor devices  540  can be associated/integrated with the individual shape charges  600  to detect if a shape charge has detonated. The sensor device(s)  540  can detect a number of attributes such as: temperature, pressure, vibration, current or voltage. A detonator can also be integrated with, or be separate from, the controller  530 . 
     FIG. 3  shows an embodiment of a shape charge  600  that can be incorporated into the perforating gun  500  as shown in  FIG. 2 . The shape charge  500  has a casing  610  and a liner  620 . The casing  610  and the liner  620  contain explosive material  630 . When the explosive material  630  detonates, the liner  620  is propelled outward in a direction away from the casing  610 . The propulsion of the liner  620  is generally well known in the art of shape charges and is therefore not specifically described herein. A primer  640  can be used to detonate the explosive material  630 . 
   During operation, an uphole controller  550  in  FIG. 2  can be located uphole from the perforating gun  500 . Preferably the uphole controller is at surface. The uphole controller can be connected to the communication medium  300  of the detonating cord  1 . Alternately, the uphole controller can be connected to a communication line(s) (not shown) that in turn connects with the communication medium  300 . The uphole controller can send signals to the communication medium  300  and receive signals transmitted through the communication medium  300 . 
   Some control operations that are contemplated are transmission of sensor signals from the sensor  540  to the uphole controller. Any number of sensors can be integrated with the perforating gun  500 . The sensors can communicate with the communication medium  300 , preferably via the downhole controller  530 , to send signals indicating the sensed parameters uphole to the uphole controller. Some aspects that can be detected are: pressure, temperature, acceleration, orientation, vibration, voltage or current. 
   The uphole controller can send signals through the communication medium  300  downhole to the downhole controller  530 . The signals from the uphole controller can instruct certain operations for the downhole controller  530 , e.g., arm a firing mechanism of the perforating gun  500 , detonate the shape charges  600  in a particular order, detonate the shape charges  600  at a particular time, detonate the shape charges  600  after a period of time has elapsed, detonate once a certain depth has been reached, detonate once a pressure is reached, or detonate once an electronic or fiber-optic signal is received. The electronic, fiber-optic or pressure signal can be coded and can be addressed to a specific downhole controller. 
   As noted above, a number of perforating guns  500  can be connected in sequence, thereby producing a perforating gun string. When multiple perforating guns  500  are connected, the detonating cord  1  of one perforating gun  500  can be connected to the detonating cord  1  of another adjacent perforating gun  500 . In that respect, it is possible to have downhole controllers  530  in each perforating gun  500  of a gun string, or less than all the perforating guns  500  of a gun string. For example, one controller  530  could be connected to shape charges  600  of other perforating guns  500  by way of the detonating cords  1  connected between adjacent perforating guns  500 . Also, it is possible that detonating cords  1  of perforating guns  500  in a gun string not be connected, so long as the perforating guns  500  could have a controller  530  that is connected by means other than the detonating cord  1 , e.g., alternate electrical or wireless connection. 
   The preceding description of embodiments is not meant to limit the scope of the following claims, but merely to better describe certain embodiments.