Patent Application
20120154168
1. Field of the Invention
The present invention relates to communication and, in particular, to communication with devices in a borehole.
2. Description of the Related Art
In drilling and completion industries it is often necessary to drill a borehole into the earth to gain access to the hydrocarbons. Equipment and structures, such as borehole casings for example, are generally disposed in a borehole as part of the completion. Unfortunately, the environment presented deep within the borehole can place extreme demands upon the devices and structures disposed therein. For example, the devices and structures can be exposed to high temperatures and pressures that can affect their operation and longevity.
Several different methods have been utilized to communicate with the devices located either permanently or temporarily in the borehole. One approach has been to provide for communication over optical fiber. Another approach has been to communicate over electrical wires either within the drill string (e.g., wired pipe) or within a wireline. Still another approach has been to utilize mud-pulse telemetry systems.
There have also been numerous attempts to create a system that allows for wireless communication between the devices in a borehole and a surface location. Some of them work better than others.
In one embodiment, a communication system for communicating between a device in a borehole penetrating a subsurface formation and a computing device at a surface location is disclosed. The system of this embodiment includes a downhole component having a portion near the device and a photonic crystal waveguide coupled to the downhole component that is configured to receive a signal from the device and guide it towards the computing device.
According to another embodiment, a method of communicating from a downhole device located in a borehole penetrating a subsurface formation to a surface location is disclosed. The method of this embodiment includes coupling an electromagnetic (EM) signal from the device to a photonic crystal waveguide; guiding the EM signal through the photonic crystal waveguide in a direction away from the device and towards the surface location; converting the EM signal to a digital signal; and providing the digital signal to a computing device at the surface location.
In yet another embodiment, a method of communicating from a computing device at a surface location to a downhole device located in a borehole penetrating a subsurface formation is disclosed. The method of this embodiment includes converting a digital signal created by the computing device into an electromagnetic signal; coupling an electromagnetic (EM) signal to a photonic crystal waveguide; guiding the EM signal through the photonic crystal waveguide in a direction away from surface location and towards the device; receiving the EM signal at the device.
In another embodiment, a downhole component is disclosed. The downhole component of this embodiment includes a body portion and a photonic crystal waveguide coupled to the body portion, the photonic crystal waveguide configured to receive a signal from a device.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein like elements are numbered alike, in which:
According to one embodiment of the present invention, a downhole component such as, for example a drill string segment or a portion of casing, includes a waveguide formed of photonic crystals coupled thereto. In one embodiment, the waveguide is configured to guide radio or microwave frequencies from a downhole device towards the surface or from the surface towards a downhole device, or both.
A photonic crystal contains regularly repeating internal regions of high and low dielectric constant. Photons (behaving as waves) propagate through this structure—or not—depending on their wavelength. Wavelengths of light that are allowed to travel are known as modes, and groups of allowed modes form bands. Disallowed bands of wavelengths are called photonic bandgaps. As such, a particular wavelength is not allowed to pass through a photonic crystal if it is within the photonic bandgap. This property will cause photons having a wavelength in the photonic bandgap to be reflected at a boundary where the spacing of dielectric symmetry changes (i.e., where the bandgaps change).
In
As illustrated, the guide region 102 does not include holes 105. Of course, the guide region could be formed by varying the location and spacing of the holes or by otherwise varying the dielectric symmetry the waveguide 100 to form the guide region 102. Regardless of how formed, the guide region 102 is configured to allow photons of at least one wavelength to travel through it. In one embodiment, the guide region is configured to transmit EM radiation in the radio or microwave frequency ranges. Similarly, in one embodiment, the blocking regions 103 include holes 105 or other nanostructures spaced and arranged such they do not allow EM radiation in the range that the guide region 102 is configured to transmit to enter them. As such, the blocking regions 103 serve to reflect the EM radiation back and forth between them in a particular direction of travel (based on the launch angle of the EM radiation) as illustrated by arrow 106. Of course, the direction of travel could be in the opposite direction in one embodiment. It shall be understood that total internal reflection may constrain the EM radiation within the guide region 102 at the junction between the guide region 102 and another material or air.
In one embodiment, the photonic crystal 101 is formed of a high-dielectric material (e.g. RT/Duriod 6010.2) having holes 105 formed in the blocking regions 103. In another embodiment, the flat surface 104 is a metal and the “holes” 105 are a material having a higher dielectric constant that the metal.
In
As described briefly above, the photonic waveguide 100 illustrated in
The computing device 202 is coupled to a signal converter 204 by communication link 206. The signal converter 204 can be part of the computing device 202 in one embodiment. The signal converter 204 converts digital signals received from the computing device 202 into electromagnetic (EM) energy in one embodiment. In one embodiment, the signal converter 204 can receive EM energy from a source, convert it to a digital signal, and then provide it to the computing device 202. In one embodiment, the EM energy is one of: microwave frequency energy or radio frequency (RF) energy.
The system illustrated in
In one embodiment, the system 200 also includes one or more devices 212. As illustrated, the system is shown having a single device 212. Of course, the number of devices 212 is not limited as shown in
In
The system 200 illustrated in
In one embodiment, the downhole component 210 includes a photonic crystal waveguide (PCW) 218 coupled thereto. In one embodiment, the PCW 218 is fixedly attached to the downhole component 210. As illustrated, the PCW 218 is located on an interior portion of the downhole component 210. Of course, the PCW 218 could be located on an exterior portion of the downhole component 210 in one embodiment. In still another embodiment, the PCW 218 could be located between an inner and outer diameter of the downhole component 210.
As discussed above, the downhole component 210 can include a plurality of segments 212, 214, 216. As illustrated, each downhole component segment 212, 214, 216 includes a corresponding PCW segment 220, 222, 224. As illustrated, the PCW 218 is a strip. Of course, it could be formed as a tubular element in one embodiment.
According to one embodiment, the computing device 202 creates a digital signal that is converted to EM energy by the energy converter 204. The EM energy is coupled from the energy converter 204 into the PCW 218. Of course, the PCW is configured to pass EM energy having the frequencies in the range produced by the energy converter 204. Coupling energy into the PCW 218 shall be referred to from time to time herein as “launching.”
After the energy is launched into the PCW 218, it travels through the PCW in a generally downhole direction. At a communication tap location (leak region) 226 the EM energy is provided from the PCW 218 to the device 212 via communication link 228. Communication link 228 could be a wireless link in one embodiment. The device 212 includes a transmitter/receiver 230 that can receive the communication.
According to one embodiment, the device 212 creates a digital signal that is converted into EM energy and launched into the PCW 218 at the communication tap 226. In one embodiment, the conversion from the digital signal to the EM energy launched into the PCW 218 is performed by the transmitter/receiver 230. In such an embodiment, communication link 228 can be a wireless link. In one embodiment, the EM energy launched into the PCW 218 at the downhole location (i.e., at the location where the device 212 is located) is either RF or microwave energy. After being launched, the EM energy travels through the PCW 218 to the signal converter 204 where it converted to digital signal and provided to the computing device 202.
As illustrated, the signal converter 204 is shown at the surface. Of course, the signal converter 204 could be located at another location. For example, the signal converter 204 could be located within the borehole 208 in one embodiment. Furthermore, the signal converter 204 is illustrated as coupled by communication link 206 to the computing device 202. The communication link 206 can be wireless in one embodiment.
In this embodiment, the device 212 is located in or otherwise part of a downhole component 302. As illustrated, the downhole component 302 is a drill string and shall be referred to as such. The drill string 302 is formed by a plurality of segments 304, 306, 308. The segments 304, 306, 308 can be any type of element included in a typical drill string. For example, the segments could be a bottom hole assembly (BHA), a drill pipe, or a drill collar. Of course, the drill string 302 could be formed as a unitary piece in one embodiment. While not clearly illustrated, it shall be understood that each segment 304, 306, 308 meets another segment at a junction. Such a junction is typically referred to as a “joint coupling,” or more simply, as a “coupling,” in the industry.
In one embodiment, the downhole component 302 includes photonic crystal waveguide (PCW) 218 coupled thereto. In one embodiment, the PCW 218 is fixedly attached to the downhole component 302. As illustrated, the PCW 218 is located on an interior portion of the downhole component 302. Of course, the PCW 218 could be located on an exterior portion of the downhole component 302 in one embodiment. In still another embodiment, the PCW 218 could be located between an inner and outer diameter of the downhole component 302.
As discussed above, the downhole component 302 can include a plurality of segments 304, 306, 308. As illustrated, each downhole component segment 304, 306, 308 includes a corresponding PCW segment 312, 314, 316. As illustrated, the PCW 218 is a strip. Of course, it could be formed as a tubular element in one embodiment.
Communication between the device 212 and the computing device 202 shown in
It shall be understood that in one embodiment, the PCW is arranged on the segments of the downhole components disclosed herein in a such a manner that the guide region of a PCW on/in one segment can be aligned with the guide regions of a PCW on another segment.
The PCW 400 of this embodiment is separated from the downhole component 402 by spacers 404. In one embodiment, the spacers 404 are arranged to ensure that the guide region 406 does not contact the downhole component 402. In this manner, EM energy traveling through the guide region is not transferred to the downhole component 402. Rather, the principle of total internal reflection bounds the EM energy such that it propagates in the “y” direction between the upper surface 410 and the lower surface 412 of the PCW 400. Reflection in the “x” direction is enforced by the blocking regions 414. Thus, the EM energy can travel in the “z” direction. In one embodiment, the PCW 400 is formed such that EM energy can radiate out from an endface 416 of the guide region. EM energy leaves the PCW 400 at the endface 416 and enters a leak region (not shown) that may include a different material than that which forms the PCW 400. For example, the leak region can include air, mud, drilling mud or other materials.
The leak region can be utilized to couple the EM energy in one PCW on one segment of a downhole component to a PCW on another segment of the downhole component. In this manner, the EM energy can traverse joints and may be able to allow for wireless communication from a downhole sensor to a surface location or vice-versa. That is, the EM energy can radiate out from the PCW and be wirelessly received by a downhole device. Alternatively, the downhole device can radiate or otherwise couple EM energy into the PCW and it can be transmitted towards the surface location.
As illustrated, the first portion 502 is separated from the second portion 504 by a leak region 510. Of course, in operation, the first portion 502 and the second portion 504 could be closely coupled to one another reducing the size of the leak region 510. Regardless of the size of the leak region 510, EM energy that is traveling along the first PCW 506 exits the PCW 506 at the leak region 510 as indicated by EM waves 512. The EM waves 512 traverse the leak region 510 and continue propagating along the downhole component 501 through the second PCW 508. At RF and microwave frequencies the interfaces between the first and second PCWs 506, 508 (e.g., leak region 510) may introduce losses. However, at these frequencies, portions 502 and 504 can be coupled within tolerances that maintain low losses between the PCWs 506, 508. In some cases, it may be beneficial to align the first PCW 506 to the second PCW 508 such that they are linearly oriented.
The PCW 604 ends at a leak region that is located at or near and the second end 605 of the downhole component 602. In
The system 600 also includes a device 212. The device 212 can transmit and receive EM waves through receiver/transmitter 230. In this manner, the device 212 can receive information from and launch information into the PCW 604.
In the above teachings it has been assumed that the EM energy can enter or leave the PCW unaided. One or more of the systems disclosed herein may include implements that allow EM energy to be launched into or received out of a PCW.
It will be appreciated that the system 700 can be any suitable computer or computing platform, and may include a terminal, wireless device, information appliance, device, workstation, mini-computer, mainframe computer, personal digital assistant (PDA) or other computing device. It shall be understood that the system 700 may include multiple computing devices linked together by a communication network. For example, there may exist a client-server relationship between two systems and processing may be split between the two.
Users of the system 700 can connect to the network through any suitable network interface 716 connection, such as standard telephone lines, digital subscriber line, LAN or WAN links (e.g., T1, T3), broadband connections (Frame Relay, ATM), and wireless connections (e.g., 802.11(a), 802.11(b), 802.11(g)).
As disclosed herein, the system 700 includes machine-readable instructions stored on machine readable media (for example, the hard disk 704) for capture and interactive display of information shown on the screen 715 of a user. As discussed herein, the instructions are referred to as “software” 720. The software 720 may be produced using software development tools as are known in the art. The software 120 may include various tools and features for providing user interaction capabilities as are known in the art.
In support of the teachings herein, various analysis components may be used, including a digital and/or an analog system. 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), cooling component, heating component, motive force (such as a translational force, propulsional force or a rotational force), magnet, electromagnet, sensor, electrode, transmitter, receiver, transceiver, antenna, controller, optical unit, optical connector, optical splice, optical lens, 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” 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” and “second” are used to distinguish elements and are not used to denote a particular order. The term “couple” relates to two devices being either directly coupled or indirectly coupled via one or more intermediate devices.
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.
