CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Application No. 14/446987, filed on July 30, 2014, which is incorporated herein by reference in its entirety.

BACKGROUND

[0002] Exploration and production of hydrocarbons generally requires that a borehole be drilled deep into the earth. The borehole provides access to a geologic formation that may contain a reservoir of oil or gas.

[0003] Drilling operations require many resources such as a drilling rig, a drilling crew, and support services. These resources can be very expensive. In addition, the expense can be even much higher if the drilling operations are conducted offshore. Thus, there is an incentive to contain expenses by drilling the borehole efficiently.

[0004] Efficiency can be measured in different ways. In one way, efficiency is measured by how fast the borehole can be drilled. Drilling the borehole too fast, though, can lead to problems. If drilling the borehole at a high rate-of-penetration results in a high probability of damaging equipment, then resources may be wasted in downtime and repairs. In addition, attempts at drilling the borehole too fast can lead to abnormal drilling events that can slow the drilling process.

[0005] There are many types of problems that can develop during drilling such as whirl and stick-slip. Stick-slip relates to the binding and release of the drill string while drilling and results in torsional oscillation of the drill string. Stick-slip can lead to damage to the drill bit and, in some cases, to failure of the drill string.

[0006] One way to transfer actual conditions from a downhole location to the surface is to utilize mud-pulse telemetry. Mud-pulse telemetry is a common method of data transmission used by measurement while drilling tools. Such tools typically include a valve operated to restrict the flow of the drilling mud (slurry) according to the digital information to be transmitted. This creates pressure fluctuations representing the information. The pressure fluctuations propagate within the drilling fluid towards the surface where they are received by pressure sensors. Another way to transfer information may be to utilize an electromagnetic (EM) telemetry system. [0007] In some cases, however, the bandwidth of EM and mudpulse telemetry systems may not be sufficient to provide all of the data required by the models in a timely manner. In some cases a wired pipe is utilized instead as a telemetry system.

SUMMARY

[0008] According to one embodiment, a drillstring communications system that includes one or more pipe segments, a communication sub coupled to the pipe segment that includes a communication sub antenna, and a leaky feeder antenna in communication with the communication sub antenna is disclosed.

[0009] In another embodiment, a method of communicating information between a downhole location and a surface computing device that includes: transmitting a signal from the downhole location through telemetry system to a surface sub; transmitting the signal or a signal formed from the signal wirelessly from the surface sub; and receiving the signal or a signal formed from the signal with a leaky feeder antenna is disclosed.

[0010] In another embodiment, a drill string communications system that includes one or more drill pipe segments; a communication sub coupled to the drill pipe segment that includes a communication sub antenna; and a plurality of leaky feeder antennas in communication with the communication sub antenna is disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Referring now to the drawings wherein like elements are numbered alike in the several Figures:

[0012] FIG. 1 is a schematic diagram showing a drilling rig engaged in drilling operations;

[0013] FIG. 2 is a simplified version of rig showing a system according to one embodiment; and

[0014] FIG. 3 shows a cut-away perspective view of a leaky feed antenna.

DETAILED DESCRIPTION

[0015] As mentioned above, while drilling, it is desired to stay in constant communication with the downhole equipment. While drilling or tripping downhole equipment (e.g. drill pipes) in or out, the elevator or topdrive is moving up and down and drillstring components. During such times it may be beneficial to provide communication from the telemetry system of the drill string to an computing device. According to one embodiment, a wireless communication systems are desired, such as a wide area local area network (WLAN) is provided that allows for communication while drill pipes are being added. The WLAN sender and receiver may be arranged such that a good transmission of data is possible at each position of the rig. This is challenging, as the rig tower is typically build of steel. It shall be understood, that other wireless standards and frequencies as e.g. blue tooth could also be used.

[0016] Connection issues could be solved by installing a leaky feeder vertical along at least part of the rig tower at or near the derrick. As used herein, "vertical" means more than 45° from horizontal. The opposite sender/receiver could be rotated or non-rotated with the drill string. It is also possible to route a leaky feeder around the surface sub to get sender and receiver adverse in each rotational position of the surface sub. One possible advantage of using a leaky feeder is that reliable communication to the downhole equipment is possible at the surface, but no wires have to be moved up and down the rig while drilling or tripping. This is of interest especially for wired pipe telemetry, as the data rate is much higher than with other telemetry systems like mud pulse or EM (electromagnetic) telemetry. With a constant communication to the downhole tools, it may be possible to detect kicks, stick slip and other dangerous situations and react instantly.

[0017] FIG. 1 is a schematic diagram showing a drilling rig 1 engaged in drilling operations. Drilling fluid 31, also called drilling mud, is circulated by pump 12 through the drill string 9 down through the bottom hole assembly (BHA) 10, through the drill bit 11 and back to the surface through the annulus 15 between the drill string 9 and the borehole wall 16. The BHA 10 may comprise any of a number of sensor modules 17, 20, 22 which may include formation evaluation sensors and directional sensors. The sensor modules 17, 20, 22 and can measure information about any of, for example, the tension or stain experienced by the drill string, temperature, pressure, and the like.

[0018] While not illustrated, it shall be understood that the drilling rig 1 can include a drill string motivator coupled to the drill string 9 that causes the drill string 9 to bore in into the earth. The term "drill string motivator" relates to an apparatus or system that is used to operate the drill string 9. Non-limiting examples of a drill string motivator include a "lift system" for supporting the drill string 9, a "rotary device" for rotating the drill string 9, a "mud pump" for pumping drilling mud through the drill string 9, an "active vibration control device" for limiting vibration of the drill string 9, and a "flow diverter device" for diverting a flow of mud internal to the drill string 9. The term "weight on bit" relates to the force imposed on the BHA 10. Weight on bit includes a weight of the drill string and an amount of force caused by the flow of mud impacting the BHA 10.

[0019] The BHA 10 also contains a communication device 19 that, in one

embodiment, can induce pressure fluctuations in the drilling fluid 31 or introduce

electromagnetic pulses into the drill string 9. The pressure fluctuations, or pulses, propagate to the surface through the drilling fluid 31 or the drill string 9, respectively and are detected at the surface by a sensor 18 and conveyed to a control unit 24. The sensor 18 is connected to the flow line 13 and may be a pressure transducer, or alternatively, may be a flow transducer. In another embodiment the communication device 19 may provide electrical signals that are carried by a wired pipe telemetry system to the surface.

[0020] In one embodiment, the control unit 24 may include programming or other means of storing models of physical characteristics of the drill string 9. For example, in one embodiment, the control unit 24 includes one or more models that model torsional oscillations in the drill string 9.

[0021] In one embodiment, the communication device 19 received data from the sensor modules 17, 20, 22 and provides that information to the control unit 24 fast enough to effectively determine the model parameters.

[0022] According an embodiment of the present invention, the BHA 10 includes a processor 21.

[0023] FIG. 1 also includes a plurality of leaky feeder antennas 25. Only one antenna is required and the lengths can vary as shown by the differences in antennas 25a and 25b.

[0024] As mentioned above, it may be desirable for the drilling crew to have access to the downhole information while drilling, tripping or adding pipe. Tripping may be necessary for a number of well operations involving a change to the configuration of the bottom-hole assembly, such as replacing the bit, adding a mud motor, or adding measurement while drilling (MWD) or logging while drilling (LWD) tools. Tripping can take many hours, depending on the depth to which drilling has progressed. The ability to maintain

communication with downhole tools and instruments during tripping (or even adding pipe) can enable a wide variety of MWD and LWD measurements to be performed during time that otherwise would be wasted. Maintaining communication during tripping may also give timely warning of lost circulation or of other potential problems, thereby enabling timely corrective action. It is also possible to transmit data while drilling or at least turning the drillstring, without an extra transfer from the rotating part to a non-rotating part on the rig. With regards to safety is also beneficial, as there is no connector for a data cable that could be a risk for an ignition source in an explosive atmosphere.

[0025] According to one embodiment, an adapter sub is provided that converts signals received at a top pipe segment into a radio frequency signal. This signal is received by leaky feeder antenna 25 and provided to, for example, control unit 24 (or other computing device) for further processing. The adapter sub 30 is best shown in FIG. 2 and shall be understood as being attached to the top 8 or one of the top segments of drill pipe. The adapter sub 30 may be connected to the swivel 27 or another such device.

[0026] With reference to FIGs. 1 and 2, as the swivel 27, and consequently, sub 30 and pipe segment 8 move up and down (as indicated by arrow 36), the location of the sub 30 is moving relative the rig 1. Providing a leaky feeder antenna 25 on the rig 1 allows for the signal to be received from the sub 30 regardless of its location. The sub 30 may include a converter 34 and an antenna 32. The antenna 32 provides signals to and receives signals from the leaky feeder antenna 25. The converter 34 converts a signal received by the antenna 32 into a format for transmission though pipe segment 8 (e.g., it may convert this signal into a signal used in a wire pipe transmission system) and vice versa.

[0027] FIG. 3 shows an example of a leaky feeder antenna 25. The leaky feeder 25 may be formed from a coaxial cable 40 having an inner conductor 48 surrounded by dielectric 46 and shielding 44. Small sections of small sections 42 of its shielding 44 are stripped away to allow radio frequency (RF) signals to escape/enter. Leaky feeders, which act as extended antennas and may also be called radiating cables.

[0028] In support of the teachings herein, various analysis components may be used, including digital and/or an analog systems. For example, the controller unit 24 and the processor 21 can include digital or analog systems. The system may have components such as a processor, storage media, memory, input, output, communications link (wired, wireless, 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 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, operator, owner, user or other such personnel, in addition to the functions described in this disclosure.

[0029] 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), vacuum supply, pressure supply, 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, mechanical unit (such as a shock absorber, vibration absorber, or hydraulic thruster), 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.

[0030] 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 term "or" when used with a list of at least two elements is intended to mean any element or combination of elements.

[0031] 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.

[0032] 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.