Patent Application
20150041215
Geologic reservoirs may be used for various purposes such as hydrocarbon production, geothermal production, or carbon dioxide sequestration. These reservoirs are typically accessed by drilling boreholes through the earth to the reservoirs.
A borehole is drilled using a drill bit that is rotated by drill pipes coupled together in series and generally known as a drill string. As the borehole is being drilled, several instruments or tools disposed at the drill string may perform measurements that may be used to monitor drilling operations or characterize the earth formation being drilled. In order to provide these measurements to an operator, processing system or controller disposed at the surface of the earth in real time, these measurements may be transmitted electrically via a transmission line or cable disposed in the drill string. Because signals carrying the measurement information must traverse all of the drill pipes between the signal source and a receiver disposed at the surface of the earth, signal couplers are installed at the ends of the drill pipes. The signal couplers allow the signal to be transmitted from one drill pipe to the adjacent drill pipe that is connected to it. These couplers may be recessed into the drill pipe making it difficult to connect them to a signal transmission line, which is even further recessed in the drill pipe. Hence, apparatus and method that improves the process of making those connections would be well received in the drilling industry.
Disclosed is an apparatus for communicating a signal downhole. The apparatus includes: a drill pipe configured to be rotated to drill the borehole; a tube under axial tension and secured in the drill pipe, wherein the axial tension occurs at least with the drill pipe not under axial tension; a connector sleeve sealed to an end of the tube and configured to secure the tube under the axial tension to the drill pipe and to provide a sealing surface for a connector to seal to; and a transmission line configured to communicate the signal disposed in the tube and having a length greater than the length of the tube and extending past the connector sleeve.
Also disclosed is a method for building an apparatus for communicating a signal downhole. The method includes: selecting a drill pipe; placing a tube in axial tension, wherein the axial tension occurs at least with the drill pipe not under axial tension; securing the tube to the drill pipe using a connector sleeve that is configured to secure the tube under the axial tension to the drill pipe and to provide a sealing surface for a connector to seal to; and disposing a transmission line configured to communicate the signal into the tube, the transmission line having a length greater than the length of the tube and extending past the connector sleeve.
Further disclosed is a method for communicating a signal downhole. The method includes: disposing a drill pipe in a borehole; and communicating the signal downhole using a transmission line disposed in a tube under axial tension in the drill pipe and configured to communicate the signal, the axial tension occurring at least with the drill pipe not under axial tension wherein a connector sleeve is secured to an end portion of the tube and is configured to secure the tube under the axial tension to the drill pipe and to provide a sealing surface for a connector to seal to and the transmission line has a length greater than the length of the tube and extending past the connector sleeve.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
A detailed description of one or more embodiments of the disclosed apparatus and method presented herein by way of exemplification and not limitation with reference to the figures.
Disclosed are apparatus and method making connections to a signal transmission line disposed in a drill pipe. The transmission line is disposed in a tube in the drill pipe. The tube protects the transmission line from drilling fluid flowing in the interior of the signal transmission line. The signal transmission line is made purposely longer than the length of the tube. The length of the transmission line in excess of the tube length is selected to enable connection with a coupler that is configured to transmit signals to or receive signals from an adjacent coupler in an adjacent connected drill pipe. After the connection is made, the excess length of the transmission line is stored in the tube.
It can be appreciated that the transmission line 5 may be configured to convey electrical signals or optical signals. To convey electrical signals, the transmission line 5 may include two or more electrical conductors, and the cooperative signal couplers may be devices or antennas for electromagnetic communication between two adjacent signal couplers. Non-limiting embodiments of the transmission line 5 for communicating electrical signals include a coaxial cable, a triaxial cable, a twisted pair cable, a ribbon cable, and insulated conductors. To convey optical signals, the transmission line 5 may include one or more optical fibers and the cooperative signal couplers may be optical couplers having optical mating surfaces recessed in the drill pipe mating surfaces.
Reference may now be had to
Two tubes 20 each secured to a connector sleeve 21 are illustrated in
As illustrated in
It can be appreciated that increasing the amount of stretching, but still being within the elastic deformation range, may increase the amount of rigidity and resistance to flexing and, thus, prevent damage from occurring in the tube 20. In addition, by resisting flexing the tube 20 may be held firmly in place so as not to interfere with tools that may be conveyed through the interior or the drill string 9. It can be appreciated that increasing the amount of stretching, but still being within the elastic deformation range, may increase the natural resonant frequency of the tube 20 such that the resonant frequency is turned or shifted in a way to prevent damage during drill string vibration.
The tube 20 and the connector sleeve 21 are made from a high strength material. The term “high strength” relates to the material having a high enough strength to be resistant to deformation during normal use. In one or more embodiments, the tube and the connector sleeves are made from a metal alloy such as a high strength stainless steel alloy. Alternatively, in one or more embodiments, the tube is made from a composite material that has an elastic deformation property. Similarly, the connector sleeves may also be made of a composite material. The materials for the tube and connector sleeves are selected to be compatible with a process for securing the connector sleeves to the tube. In one or more embodiments, the connector sleeve 21 surrounds the tube 20 where the sleeve is secured to the tube resulting in the outer diameter of the sleeve being greater than the outer diameter of the tube. Non-limiting embodiments of the securing process include welding, brazing, soldering, friction fitting, swaging, and applying an adhesive. Swaging may be performed hydraulically or by use of a ferrule. In one example of friction fitting, connector sleeves are in a cryogenic condition that expands the inner diameter of these devices. When allowed to heat up, the diameter of these devices decreases to provide the friction fit. It can be appreciated that any of these processes provides for a fluid tight seal that prevents drilling fluid from entering the tube and interfering with the transmission line.
As the signal coupler 60 is being inserted into the recess 25, the excess length or slack of the transmission line 5 is inserted into the tube 20. In one or more embodiments, the transmission line 5 rests free or has freedom of movement within the tube 20 in order to enable each end of the transmission line to be extended from either end of the tube so that signal coupler connections can be made. Another advantage of having the transmission line 5 rest free in the tube 20 is that the line in the tube can be displaced in order to make room for the slack that is being inserted into the tube as the signal coupler is being inserted into the corresponding recess. In one or more embodiments, the transmission line 5 includes a signal transmission medium (e.g., electrical conductors) that is wrapped around or woven through an elastic material such that the transmission line can be pulled to extend its length beyond the length of the tube and when released the transmission line will retract into the tube. In one or more embodiments, the transmission line 5 is a stretchable elastic electrical cord such one referred to as Roboden and available from Asahi Kasel Fibers of Japan.
It can be appreciated that minimum additional tube stretching is required to attach one of the connector sleeves before the tube 20 is allowed to retract into the drill pipe 8. For example, with a drill pipe that is 30 feet long, only about two inches or 0.5% additional stretch is required to attach one of the devices using other methods to secure without the necessity of direct access like described above and would further limit the required stretch.
While the tube 20 is illustrated as being straight from the box end to the pin end of the drill pipe 8, it can be appreciated that the tube can be deviated. The tube may be deviated using restraining devices (not shown) that are configured to restrain the tube radially and yet allow the axial tension to be conveyed axially. Alternatively, the bores in the drill pipe for accepting the tube may be deviated with respect to the center line of the drill pipe.
The above disclosed techniques provide several advantages. One advantage is that having the tube under axial tension provides greater rigidity and therefore greater resistance to flexing due to drill string vibration. Another advantage to having the tube disposed in each drill pipe is to protect the transmission line from the flow of drilling fluid internal to the drill pipes.
In support of the teachings herein, various analysis components may be used, including a digital and/or an analog system. For example, the downhole tools 10, the downhole electronics 11, or the computer processing system 12 may include digital and/or analog systems. The system may have components such as a processor, storage media, memory, input, output, communications link (wired or optical or other), user interfaces, software programs, signal processors (digital or analog) and other such components (such as resistors, capacitors, inductors and others) to provide for operation and analyses of the apparatus and methods disclosed herein in any of several manners well-appreciated in the art. It is considered that these teachings may be, but need not be, implemented in conjunction with a set of computer executable instructions stored on a non-transitory computer readable medium, including memory (ROMs, RAMs), optical (CD-ROMs), or magnetic (disks, hard drives), or any other type that when executed causes a computer to implement the method of the present invention. These instructions may provide for equipment operation, control, data collection and analysis and other functions deemed relevant by a system designer, owner, user or other such personnel, in addition to the functions described in this disclosure.
Further, various other components may be included and called upon for providing for aspects of the teachings herein. For example, a power supply (e.g., at least one of a generator, a remote supply and a battery), magnet, electromagnet, sensor, electrode, transmitter, receiver, transceiver, antenna, controller, optical unit, connector, splice, electrical unit or electromechanical unit may be included in support of the various aspects discussed herein or in support of other functions beyond this disclosure.
Elements of the embodiments have been introduced with either the articles “a” or “an.” The articles are intended to mean that there are one or more of the elements. The terms “including” and “having” and the like are intended to be inclusive such that there may be additional elements other than the elements listed. The conjunction “or” when used with a list of at least two terms is intended to mean any term or combination of terms. The terms “first,” “second” and the like do not denote a particular order, but are used to distinguish different elements.
The flow diagrams depicted herein are just examples. There may be many variations to these diagrams or the steps (or operations) described therein without departing from the spirit of the invention. For instance, the steps may be performed in a differing order, or steps may be added, deleted or modified. All of these variations are considered a part of the claimed invention.
While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
It will be recognized that the various components or technologies may provide certain necessary or beneficial functionality or features. Accordingly, these functions and features as may be needed in support of the appended claims and variations thereof, are recognized as being inherently included as a part of the teachings herein and a part of the invention disclosed.
While the invention has been described with reference to exemplary embodiments, it will be understood that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications will be appreciated to adapt a particular instrument, situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
