Acoustic Telemetry For Monitoring An Annulus Between The Production Casing And The Next Outer Casing Of A Well

Abstract

A tool is positioned inside a production casing in a well such that at least one acoustic telemetry device provided in an extendable arm of the tool is located less than six inches away from at least another acoustic telemetry device provided in a casing module. Such proximity can ensure that the acoustic signals can be transmitted between acoustic telemetry devices through the production casing. The tool identifies a condition in the well that is measured in the B-annulus between the production casing and a next outer casing. In turn, the tool broadcasts the measured condition in the well to the Earth's surface where the measurement can be used to inform a decision about the well.

What is claimed is: 
     
         1 . An acoustic telemetry system for transmitting signals from a sensor, the system comprising:
 a tool conveyable inside a casing of a well, the tool including a first acoustic telemetry device, the first acoustic telemetry device being capable of receiving acoustic signals from a second acoustic telemetry device,   wherein the first acoustic telemetry device is mounted on an arm coupled to the tool, the arm being extendable from the tool toward an inner surface of the casing such that the first acoustic telemetry device is pressed against the inner surface of the casing; and   a casing module including the sensor and the second acoustic telemetry device, the sensor being capable of measuring a condition in the well outside the casing, the second acoustic telemetry device being capable of transmitting acoustic signals indicative of the condition in the well measured by the sensor through the casing and to the first acoustic telemetry device,   wherein the second acoustic telemetry device is pressed against an outer surface of the casing.   
     
     
         2 . The system of  claim 1 ,
 wherein the tool further includes a plurality of first acoustic telemetry devices, each of the plurality of first acoustic telemetry devices being configured to receive acoustic signals from the second acoustic telemetry device, and   wherein each of the plurality of first acoustic telemetry devices is mounted on a respective one of a plurality of arms, the plurality of arms being positioned around a periphery of the tool, each of the plurality of arms being coupled to the tool and extendable from the tool toward the inner surface of the casing such that each of the plurality of first acoustic telemetry devices is pressed against the inner surface of the casing.   
     
     
         3 . The system of  claim 2 , wherein each of the plurality of arms further includes several acoustic telemetry modules positioned along a longitudinal axis of the tool, each of the plurality of arms being extendable from the tool toward the inner surface of the casing such that each of the several acoustic telemetry modules is pressed against the inner surface of the casing. 
     
     
         4 . The system of  claim 1 , further comprising a plurality of casing modules, each of the plurality of casing modules including a corresponding one of a plurality of second acoustic telemetry devices, each of the plurality of second acoustic telemetry devices being configured to transmit acoustic signals indicative of the condition in the well,
 wherein each of the plurality of second acoustic telemetry devices is pressed against the outer surface of the casing, and   wherein the plurality of second acoustic telemetry devices are positioned around a periphery of the casing.   
     
     
         5 . The system of  claim 4 , wherein each of the plurality of casing modules includes a corresponding one of a plurality of sensors, each of the plurality of sensors being capable of measuring the condition in the well outside the casing, each of the plurality of second acoustic telemetry devices being configured to transmit acoustic signals indicative of the condition in the well measured by the corresponding one of the plurality of sensors. 
     
     
         6 . The system of  claim 1 , wherein the first acoustic telemetry device is further capable of emitting acoustic waves, wherein the second acoustic telemetry device is further capable of converting the acoustic waves into a DC voltage, wherein the casing module further includes a rechargeable battery or a capacitor coupled to the DC voltage, and wherein the sensor is powered by the rechargeable battery or the capacitor. 
     
     
         7 . The system of  claim 6 , wherein the second acoustic telemetry device comprises a piezoelectric material. 
     
     
         8 . A method of acoustic telemetry for transmitting signals from a sensor, the method comprising:
 positioning a tool inside a casing of a well, the tool including a first acoustic telemetry device, wherein the first acoustic telemetry device is mounted on an arm coupled to the tool;   extending the arm from the tool toward an inner surface of the casing such that the first acoustic telemetry device is pressed against the inner surface of the casing;   measuring a condition in the well outside the casing with a sensor included in a casing module;   transmitting acoustic signals indicative of the condition in the well measured by the sensor to the first acoustic telemetry device with the second acoustic telemetry device, wherein the second acoustic telemetry device is included in the casing module and is pressed against an outer surface of the casing; and   receiving the acoustic signals transmitted through the casing with the first acoustic telemetry device.   
     
     
         9 . The method of  claim 8 ,
 wherein the tool further includes a plurality of first acoustic telemetry devices, each of the plurality of first acoustic telemetry devices being configured to receive acoustic signals from the second acoustic telemetry device, and   wherein each of the plurality of first acoustic telemetry devices is mounted on a respective one of a plurality of arms, each of the plurality of arms being coupled to the tool, the plurality of arms being positioned around a periphery of the tool,   the method further comprising extending each of the plurality of arms from the tool toward the inner surface of the casing such that each of the plurality of first acoustic telemetry devices is pressed against the inner surface of the casing,   wherein the tool is positioned inside the casing of the well such that at least one of the plurality of first acoustic telemetry devices is located less than six inches away from the second acoustic telemetry device, and   wherein the acoustic signals transmitted from the second acoustic telemetry device are received by the at least one of the plurality of first acoustic telemetry devices.   
     
     
         10 . The method of  claim 9 , wherein each of the plurality of arms includes several acoustic telemetry modules positioned along a longitudinal axis of the tool, each of the plurality of arms being extendable from the tool toward the inner surface of the casing such that each of the several acoustic telemetry modules is pressed against the inner surface of the casing. 
     
     
         11 . The method of  claim 8 , comprising transmitting acoustic signals indicative of the condition in the well with each of a plurality of second acoustic telemetry devices, each of the plurality of second acoustic telemetry devices being included in a corresponding one of a plurality of casing modules,
 wherein each of the plurality of second acoustic telemetry devices is pressed against the outer surface of the casing,   wherein the plurality of second acoustic telemetry devices are positioned around a periphery of the casing,   wherein the tool is positioned inside the casing of the well such that at least one of the plurality of second acoustic telemetry devices is located less than six inches away from the first acoustic telemetry device, and   wherein the first acoustic telemetry device receives the acoustic signals transmitted from the at least one of the plurality of second acoustic telemetry devices.   
     
     
         12 . The method of  claim 11 , wherein each of the plurality of casing modules includes a corresponding one of a plurality of sensors, the method further comprising measuring the condition in the well outside the casing with each of the plurality of sensors, wherein each of the plurality of second acoustic telemetry devices transmits acoustic signals indicative of the condition in the well measured by the corresponding one of the plurality of sensors. 
     
     
         13 . The method of  claim 8 , wherein the casing module further includes a rechargeable battery or a capacitor coupled to a DC voltage, the method further comprising:
 emitting acoustic waves with the first acoustic telemetry device;   converting the acoustic waves into the DC voltage with the second acoustic telemetry device; and   powering the sensor with the rechargeable battery or the capacitor.   
     
     
         14 . The method of  claim 13 , wherein the second acoustic telemetry device comprises a piezoelectric material.