Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B47/00—Survey of boreholes or wells
  • E21B47/12—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B47/00—Survey of boreholes or wells
  • E21B47/12—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
  • E21B47/14—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling using acoustic waves

Definitions

• the present invention relates generally to telemetry apparatuses and methods, and more particularly to acoustic telemetry increased throughput network systems and methods for the well construction (drilling, completion) and production (e.g., oil and gas) industries.
• Acoustic telemetry is a method of communication used in the well drilling, completion and production industries.
• acoustic extensional carrier waves from an acoustic telemetry device are modulated in order to carry information via the drillpipe as the transmission medium to the surface.
• the waves Upon arrival at the surface, the waves are detected, decoded and displayed in order that drillers, geologists and others helping steer or control the well are provided with drilling and formation data.
• downhole information can similarly be transmitted via the well casings.
• Drillstring acoustic telemetry systems are commonly designed with multiple transceiver nodes located at spaced intervals along the drillstring or wellbore.
• the nodes can be configured as signal repeaters as necessary.
• Acoustic telemetry networks can function in a synchronized fashion with the operation of the nodes and repeater nodes and other system components.
• Data packets consisting of downhole sensor data were relayed node to node, in a daisy chain or linear fashion, typically beginning from a node located in the borehole apparatus (BHA), through the network to a destination, usually the surface receiver system.
• BHA borehole apparatus
• the data packets were transmitted (typically up- string) using time division multiplexing (TDM) techniques.
• TDM time division multiplexing
• an acoustic transmitter When exploring for oil or gas, and in other drilling applications, an acoustic transmitter can be placed near the BHA, typically near the drill bit where the transmitter can gather certain drilling, wellbore, and geological formation data, process this data, and then convert the data into a signal to be transmitted uphole to an appropriate receiving and decoding station.
• the transmitter is designed to produce elastic extensional stress waves that propagate through the drillstring to the surface, where the waves are detected by sensors, such as accelerometers, attached to the drillstring or associated drilling rig equipment. These waves carry information of value to the drillers and others who are responsible for steering the well. Examples of such systems and their components are shown in: Drumheller U.S. Patent No.
• a network is configured with multiple nodes using the acoustic transmission channel simultaneously, i.e., "multiplexing" the channel.
• Internode interference can be controlled by one or more methods, including the following:
• Node transmission timing nodes transmitting at separate times.
• Current (prior art) method which tends to be relatively inefficient.
• TDM time division multiplexing
• Directional transmitter and receiver configurations with nodes tuned to transmit in the direction of the desired destination node or receive in the direction of the originating node, thereby minimizing interference within the network.
• FIG. 1 is a diagram of a typical drilling rig, which can include an acoustic telemetry system with a downhole serial network embodying an aspect of the present invention.
• FIG. 2 is a fragmentary, side-elevational and cross-sectional view of a typical drillstring, which can provide the medium for acoustic telemetry transmissions for the present invention.
• FIG. 3 is a schematic diagram of a prior art linear network timing control system with nodes transmitting sequentially at different times, following a time division multiplexing (TDM) approach
• TDM time division multiplexing
• FIG. 4 is a schematic diagram of a path loss attenuation isolation system with a two- node gap transmission schedule.
• FIG. 5 is a schematic diagram of a path loss attenuation isolation system with a one- node gap transmission schedule.
• FIG. 6 is a schematic diagram of a path loss attenuation isolation system wherein nodes transmit and receive simultaneously.
• FIG. 7 is a schematic diagram of a configuration whereby a node is adapting a filter to estimate the channel between the node's transmitter and receiver.
• FIG. 8 is a schematic diagram showing receiver signal isolation from the transmitter signal.
• FIG. 9 is a schematic diagram of an increased-rate linear telemetry network scheduling system using orthogonal signal sets.
• FIG. 10 is a schematic diagram of another increased rate linear telemetry network scheduling system using orthogonal signal sets combined with simultaneous transmission and reception.
• FIG. 11 is a schematic diagram showing an example of multi-node transmission in an along-string measurement (ASM) configuration with varying/accumulating node payloads.
• ASM along-string measurement
• FIG. 12 is a schematic diagram illustrating a node receiving a portion of a desired signal transmission during an interference-free period.
• FIG. 13 is a schematic diagram showing a system using directional transceivers to suppress intra-node interference and increase network throughput.
• the reference numeral 2 generally designates a high throughput network system embodying an aspect of the present invention.
• a drilling rig 4 (FIG. 1).
• the rig 4 can include a derrick 6 suspending a traveling block 8 mounting a kelly swivel 10, which receives drilling mud via a kelly hose 11 for pumping downhole into a drillstring 12.
• the drillstring 12 is rotated by a kelly spinner 14 connected to a kelly pipe 16, which in turn connects to multiple drill pipe sections 18, which are interconnected by tool joints 19, thus forming a drillstring of considerable length, e.g., several kilometers, which can be guided downwardly and/or laterally using well-known techniques.
• the drillstring 12 can terminate at or near a bottom-hole (borehole) apparatus (BHA) 20, which can be at or near an acoustic transceiver node (Primary) Station 0 (ST0).
• BHA bottom-hole apparatus
• ST0 acoustic transceiver node
• FIG. 1 also shows the components of the drillstring 12 just above the BHA 20, which can include, without limitation, a repeater transceiver node 26 (ST1) and an additional repeater transceiver node 22 (ST2).
• ST1 repeater transceiver node 26
• ST2 additional repeater transceiver node 22
• An upper, adjacent drillpipe section 18a is connected to the repeater 22 and the transmitter 26.
• a downhole adjacent drillpipe section 18b is connected to the transmitter 26 and the BHA 20.
• a surface receiver node 21 is located at the top of the drillstring 12 and is adapted for receiving the acoustic telemetry signals from the system 2 for further processing, e.g., by a processor or other output device for data analysis, recording, monitoring, displaying and other functions associated with a drilling operation.
• FIG. 2 shows the internal construction of the drillstring 12, e.g., an inner drillpipe 30 within an outer casing 32. Interfaces 28a, 28b are provided for connecting drillpipe sections to each other and to the other drillpipe components, as described above.
• W.1 illustrates an acoustic, electromagnetic or other energy waveform transmitted along the drillstring 12, either upwardly, downwardly, or laterally (in the case of horizontal wells).
• the drillstring 12 can include multiple additional repeater transceiver nodes 22 at intervals determined by operating parameters such as optimizing signal transmission and reception with minimal delays and errors.
• the drillstring 12 can also include multiple sensors along its length for producing output signals corresponding to various downhole conditions.
• Data packets contain sensor or node status data and are transmitted from the primary node (e.g., STO, typically the deepest node) and relayed from node-to-node in a daisy-chain (herein interchangeably referred to also as linear or serial) fashion to the surface receiver (Surface Rx) 21, which is generally located at or near the wellhead.
• the data packets include sensor measurements from the BHA 20 and other sensors along the drillstring 12.
• Such data packet sensor measurements can include, without limitation, wellbore conditions (e.g., annular/bore/differential pressure, fluid flow, vibration, rotation, etc.).
• Local sensor data can be added to the data packet being relayed at each sensor node, thus providing along-string- measurements (ASMs).
• a single node functions as the master node (e.g., STO) and is typically an edge node at the top or bottom of the drillstring 12. The master node monitors well conditions and sends data packets of varying type and intervals accordingly.
• FIG. 3 shows the operation of a prior art linear telemetry network scheduling configuration where node transmissions are scheduled for separate non-overlapping time windows in order to prevent inter-node interference and the associated degradation in link performance (reliability and range).
• TDM time division multiplexing
• multiple nodes are configured for using the acoustic transmission channels at the same time, i.e., "multiplexing" the drillstring channel. Multiplexing, with multiple nodes transmitting simultaneously, decouples network throughput dependency on the number of nodes, and increases performance. However, if not mitigated, multiple nodes transmitting
• One or more of the following methods can be implemented to control internode interference during multi-node transmission: • Signal attenuation, with nodes transmitting simultaneously and interference being suppressed by differences in propagation distance and associated path loss, and perhaps further optimized through adjustment of node transmission power level.
• FIG. 4 shows a 2-node gap multiplexing scheduling configuration.
• Interfering transmissions are mitigated by physical separation (e.g., 2-node gap).
• This configuration is applicable to electromagnetic pulse systems as well as acoustic, and is further applicable to downlink, uplink and bi-directional networks.
• Interfering transmissions are mitigated by physical separation and associated signal propagation path loss: 3 -link propagation path loss attenuation (desired) versus 1-link propagation path loss attenuation (interference). Additional interference minimization can be achieved through adjustment of the transmitter output power levels to minimize interference at one location, while providing sufficient signal power at the desired node receiver. Update interval/rate and network throughput are thus fixed regardless of the number of network nodes. Only latency increases with node number.
• the interference between nodes can be further managed by coordinating network timing in such a manner that, while multiple node transmissions overlap in time, the desired signal precedes the anticipated interferer signal such that a sufficient portion of the desired signal experiences no interference allowing the receiving node to achieve more reliable signal detection, timing and phase recovery, and decoding once the interfering node begins
• This method allows the receiver to favour the desired signal over the interferer. See, e.g., FIG. 12, which is discussed below.
• FIG. 5 shows a 1-node gap multiplexing scheduling configuration wherein multiple nodes are transmitting at the same time. This configuration is more aggressive than the 2-node gap configuration shown in FIG. 4, having less interference suppression. Interfering transmissions are mitigated by physical separation and associated path loss: 1-link path loss attenuation (desired) versus 2-link path loss attenuation (interference). Update interval/rate and network throughput are thus fixed regardless of the number of network nodes. Only latency increases with node number.
• FIG. 6 shows scheduling with an update rate which can be fixed at approximately 2t tx , for example, regardless of the number of nodes. Only latency increases with node number.
• the receiver must be able to operate during self-transmission, without being excessively degraded by self-interference. This can be accomplished by assigning non-interfering frequency or orthogonal signal sets to the transmitter and receiver. If the transmitter and a receiver operate in the same channel (time, frequency), or further interference suppression is desired, high-power interfering self-transmission signals can be isolated from received signals through channel estimation techniques, as described below.
• FIG. 7 shows a "receive-while-transmitting" configuration wherein an estimating function with a feedback loop is used to estimate the in-node transmitter to receiver channel.
• a transmitter e.g., a piezo-electric stack, in the case of acoustics
• receiver accelerometer, in the case of acoustics
• FIG. 8 shows how the estimated intra-node channel can be used to suppress self- interference. Specifically, by applying an estimated channel filter to the known transmitted signal (as derived in FIG. 7), to translate the signal to how the receiver would perceive it, and subtracting it from the composite receive signal (self-interference from transmitter + desired receive signal originating from another node) to provide output corresponding to the desired receive signal only.
• FIG. 9 shows an increased rate repeater scheduling configuration assigning orthogonal (i.e., low-interference) signal sets (indicated by ⁇ , ⁇ ) to transmitter and receiver nodes, thereby allowing multiple signals in respective channels simultaneously, increasing the update rate and the effective data rate.
• the signal sets can be reused once interference nodes are sufficiently separated to ensure adequate interference isolation.
• the update interval, t up date is fixed at ⁇ 2t tti regardless of the number of repeaters and only latency increases.
• the concept is the application of orthogonal multiple access techniques to increase channel efficiency (e.g., CDMA - Code Domain Multiple Access, FDMA - Frequency Domain Multiple Access, OFDM - Orthogonal Frequency Domain Multiplexing, etc.) as an alternative to the relatively inefficient TDM (Time Division Multiplexing) methods.
• CDMA Code Domain Multiple Access
• FDMA Frequency Domain Multiple Access
• OFDM Orthogonal Frequency Domain Multiplexing
• Examples of low-interference signal sets include: signals of non-overlapping frequencies (Frequency Division Multiplexing (FDM)), which can be contiguous frequency blocks (e.g., different passbands) or interleaved blocks (e.g., OFDM); signals of low cross- correlations, such as up/down, linear/exponential chirps, pseudorandom noise (PRN) sequences (Code Division Multiplexing (CDM)), e.g., Walsh codes, Hadamard, etc.; and signals transmitted on separate, isolated mediums (channels): acoustic, electromagnetic pulse, and mud pulse (MP); and propagation modes (e.g., axial, longitudinal and spiral).
• FDM Frequency Division Multiplexing
• FDM Frequency Division Multiplexing
• OFDM Orthogonal frequency division Multiplexing
• PRN pseudorandom noise
• CDM Code Division Multiplexing
• channels acoustic, electromagnetic pulse, and mud pulse (MP); and propagation modes (e.g.,
• FIG. 10 shows orthogonal signal sets combined with simultaneous transmit and receive, to providing an update rate, t up date, fixed at ⁇ t tt , regardless of the number of nodes whereby only latency increases with node number.
• Node receivers are able to operate during transmission with minimized intra-node (self) interference due to transmitter-receiver signal orthognality, as previously discussed. If the transmitter and the receiver operate in the same channel, high-power interfering self-transmission signals can be isolated from received signals through channel estimation techniques, as described below.
• FIG. 11 is a schematic diagram showing an example of an along-string measurement (ASM) configuration with varying/accumulating node payloads and signal propagation interference isolation.
• ASM along-string measurement
• FIG. 12 shows signal transmission scheduling refinement whereby a desired transmission (e.g., from M2 T x to M2 R x ) precedes an interfering transmission (e.g., from Ml ⁇ to M2 Rx), creating a short period of interference-free reception of the desired signal.
• This interference-free period improves signal detection, timing and phase recovery, effectively allowing the receiver (e.g., M2 Rx) to "lock" onto the desired signal, and generally improve link robustness.
• FIG. 13 shows a system with directional transceivers for interference suppression.
• the node receivers are tuned to receive upwardly-traveling signals and to suppress/reject downwardly-traveling signals. This can be accomplished by equipping an acoustic node with multiple transmitters and receivers, and phasing their outputs such that directional transmission or reception is achieved (e.g., transmissions propagate only uphole and receivers only detect signals originating from downhole, and vice-versa). The details of such an operation would be known to one versed in antenna beam forming techniques, and as such will not be elaborated in this text. Receive and transmit directionality can be exploited together, or individually, to suppress interference between nodes, enabling multiple nodes to transmit at the same time.
• Remaining interference is separated by a two-node gap.
• EM electromagnetic

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• 2014
  • 2014-03-17 EP EP14762714.5A patent/EP2972527B1/de active Active
  • 2014-03-17 WO PCT/US2014/030682 patent/WO2014145848A2/en active Application Filing
  • 2014-03-17 US US14/215,617 patent/US20140266769A1/en not_active Abandoned
  • 2014-03-17 CA CA2906905A patent/CA2906905C/en active Active
  • 2014-03-17 BR BR112015023566A patent/BR112015023566A2/pt not_active IP Right Cessation

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