Network telemetry system and method

Abstract

A telemetry system produces, transmits and receives signal sets from network nodes, which correspond to transceiver stations. Repeater scheduling and other interference mitigating techniques are utilized to simultaneously transmit from multiple nodes with minimized network degradation. Update interval/rate and network throughput are thereby fixed regardless of the number of network nodes and a network telemetry method is provided using the system.

1 . A wireless telemetry network system, which includes:
 multiple network nodes;   a sensor associated with one or more of said nodes and adapted for providing output comprising signal data corresponding to an operating or status condition;   a transmitter associated with one of said nodes for propagating said signal data between nodes;   a receiver associated with one of said nodes for receiving signals from other nodes;   multiple network nodes adapted for receiving said signal data; and   said system being adapted for transmitting telemetry signals across multiple network links simultaneously.   
     
     
         2 . A linear wireless telemetry network system for a well including a wellbore structure extending subsurface downwardly from the surface, which telemetry network system includes:
 multiple network nodes distributed along the wellbore;   at least one said node including a sensor adapted for providing a signal data set output corresponding to a downhole condition;   a transmitter for propagating said signal between nodes;   a receiver for receiving said signal from other nodes; and   said system being adapted for transmitting telemetry signals across multiple network links simultaneously.   
     
     
         3 . The telemetry system according to  claim 2 , which includes:
 said telemetry signals being chosen from among the group comprising acoustic, electromagnetic (EM), mud pulse (MP) and optical.   
     
     
         4 . The telemetry system according to  claim 2  wherein said signal sets comprise orthogonal (low interference/cross-correlation) signal sets assigned to network nodes so as to reduce interference at adjacent nodes. 
     
     
         5 . The telemetry system according to  claim 4  wherein said telemetry signals are located in multiple, minimally-interfering frequency channels within a medium and/or separate mediums chosen from among the group comprising acoustic, EM and MP. 
     
     
         6 . The telemetry system according to  claim 2  wherein:
 said nodes have predefined separations (and therefore a signal propagation associated attenuation level) and/or transmission power levels adapted so as to maintain interference at receiver locations within a tolerable range. 
 
     
     
         7 . The telemetry system according to  claim 6 , which includes:
 an update interval rate and network throughput being fixed regardless of the number of network nodes.   
     
     
         8 . The telemetry system according to  claim 2 , which includes:
 a respective node including a transmitter and a receiver; and   the respective node simultaneously transmitting and receiving.   
     
     
         9 . The telemetry system according to  claim 8 , which includes a filter adapted to an approximation of the channel between the respective node's transmitter and receiver. 
     
     
         10 . The telemetry system according to  claim 8 , which includes said receiver being adapted for receiving with mitigated self-interference during transmission. 
     
     
         11 . The telemetry system according to  claim 9 , which includes an estimation function including:
 a transmitter-to-receiver intranode channel providing an output;   said adaptive filter having the signal destined for transmission as a reference input;   a summer receiving outputs from said receiver channel and said adaptive filter;   said summer providing an error signal as a feedback output to said adaptive filter; and   said adaptive filter being adjusted so as to minimize error signal.   
     
     
         12 . The telemetry system according to  claim 9 , which includes a receiver signal isolation function including:
 an estimated intranode transmitter-to-receiver channel filter having the signal destined for transmission as an input from the transmitter and providing an output that is the estimated transmitter signal as perceived by the receiver;   a summer receiving inputs from said adaptive filter and the receiver signal output that are synchronized in time; and   said summer providing an output comprising the received signal with reduced transmitter signal content.   
     
     
         13 . The telemetry system according to  claim 2 , which includes:
 said transmitter and said receiver operating in the same channel;   said received signals being isolated from each other;   said receiver being configured to receive with minimized self-interference during transmission; and   said control system including a function for favoring a desired signal over an interferer signal.   
     
     
         14 . The telemetry system according to  claim 2  which includes:
 said control system function coordinating network timing whereby a desired signal precedes in time an anticipated, overlapping interferer signal creating an interference-free time period at a node for reception of a portion of the desired signal, thereby allowing the node receiver to lock onto the desired signal. 
 
     
     
         15 . The telemetry system according to  claim 2 , which includes:
 multiple receivers within a node with signal outputs which are phased and combined in such a manner to form a phased array that gives rise to directional discrimination of incoming signals to minimize interference from an undesired node transmissions arriving from another direction.   
     
     
         16 . The telemetry system according to  claim 2 , which includes:
 multiple transmitters within a node with output signals phased in such a manner so as to propagate outgoing signals in one direction only and minimizing interference at another node.   
     
     
         17 . The telemetry system according to  claim 2 , which includes:
 said directional receivers being adapted to suppress undesired interfering signals arriving at the receiver from one direction, while receiving desired signals from another direction.   
     
     
         18 . A method of transmitting acoustic telemetry signals in a well including a wellbore structure extending subsurface downwardly from the surface, which method includes the steps of:
 defining with said structure a linear/daisy-chain network;   providing multiple network nodes positioned along said structure;   transmitting said signals in signal sets comprising orthogonal (low interference) signal sets assigned to network nodes to reduce inter-node interference;   pre-defining node separations and/or transmission power levels;   predefining tolerable interference ranges for said receivers;   maintaining interference at receiver locations within tolerable, predefined ranges through signal propagation attenuation;   providing a sensor associated with one or more of said nodes and adapted for providing output comprising signal data corresponding to an operating, status, or wellbore condition;   providing a transmitter associated with one of said nodes for propagating said signal data between nodes;   providing a receiver associated with one of said nodes;   receiving with said receiver signals from other nodes;   receiving said signal data with said multiple network nodes; and   transmitting telemetry signals across multiple network links simultaneously.   
     
     
         19 . The method according to  claim 18 , which includes the additional step of:
 providing said well with a node located at said surface and a bottom hole assembly (BHA) located at the bottom of said well;   providing sensors configured to monitor operating conditions near or at the BHA;   generating said signals with data corresponding to said BHA operating stations;   transmitting said BHA operating condition data signals to said surface node; and   exporting said BHA operating condition data signals to a remote data processing system configured to monitor operating conditions at said well.   
     
     
         20 . The method according to  claim 18 , which includes the additional step of generating said telemetry signals using a signal type chosen from among the group comprising: acoustic; electromagnetic (EM); mud pulse (MP); and optical.