Wellbore condition monitoring sensors

Abstract

Disclosed is an apparatus for estimating a downhole property of interest. The apparatus includes a carrier configured to be conveyed in a borehole penetrating an earth formation and carry a releasable sensor. The sensor is configured to be released by the carrier into drilling fluid and to sense the property. The sensor includes a memory to store sensed property data. The data can be downloaded from the memory wirelessly with the sensor in the drilling fluid or by retrieving the sensor from the drilling fluid.

What is claimed is: 
     
         1 . An apparatus for estimating a downhole property of interest, the apparatus comprising:
 a carrier configured to be conveyed in a borehole penetrating an earth formation and carry a releasable sensor; and   a sensor configured to be released by the carrier into drilling fluid and to sense the property;   wherein the sensor comprises a memory to store sensed property data.   
     
     
         2 . The apparatus according to  claim 1 , wherein the carrier is configured to release the sensor external to the carrier and into the borehole where the sensor travels uphole in the drilling fluid. 
     
     
         3 . The apparatus according to  claim 1 , where the carrier is configured to release the sensor internal to the carrier where the sensor exits a drill bit into the borehole where the sensor travels uphole in the drilling fluid. 
     
     
         4 . The apparatus according to  claim 1 , further comprising a receiving device configured to receive the sensor from the borehole fluid or the sensed memory data from the sensor that has been released from the carrier. 
     
     
         5 . The apparatus according to  claim 4 , wherein the receiving device comprises a screen configured to entrap the sensor. 
     
     
         6 . The apparatus according to  claim 4 , wherein the receiving device comprises a magnet configured to attract the sensor in the borehole fluid. 
     
     
         7 . The apparatus according to  claim 4 , wherein the receiving device comprises a first transducer configured to receive signals from the sensor. 
     
     
         8 . The apparatus according to  claim 7 , wherein the first transducer comprises an antenna and the signals are electromagnetic signal. 
     
     
         9 . The apparatus according to  claim 7 , wherein the sensor further comprises a second transducer configured to transmit the signals to the receiving device in order to transmit the sensed property data. 
     
     
         10 . The apparatus according to  claim 9 , wherein the second transducer comprises an antenna and the signals are electromagnetic signals. 
     
     
         11 . The apparatus according to  claim 9 , wherein the sensor further comprises a transmitter configured to transmit the sensed property data using the second transducer. 
     
     
         12 . The apparatus according to  claim 9 , wherein the second transducer is configured to transmit acoustic, magnetic or optical signals. 
     
     
         13 . The apparatus according to  claim 4 , the sensor comprising a connector configured to receive data from the carrier or download data to the receiving device. 
     
     
         14 . The apparatus according to  claim 4 , wherein the sensor comprises a beacon configured to emit a signal to activate or deactivate the receiving device. 
     
     
         15 . The apparatus according to  claim 1 , wherein the sensor is encapsulated in a protective coating. 
     
     
         16 . The apparatus according to  claim 1 , wherein the sensor comprises a thermocouple configured to measure temperature. 
     
     
         17 . The apparatus according to  claim 1 , wherein the sensor comprises a flexural mechanical resonator configured to measure a property of a downhole fluid. 
     
     
         18 . The apparatus according to  claim 17 , wherein the flexural mechanical resonator comprises a plurality of flexural mechanical resonators with each resonator tuned to a specific range of measurements. 
     
     
         19 . The apparatus according to  claim 1 , wherein the sensor comprises a processor configured to operate the sensor to obtain the sensed property data and to store the sensed property data in the memory. 
     
     
         20 . The apparatus according to  claim 19 , wherein the processor comprises a clock configured to provide a time at which each measurement is performed. 
     
     
         21 . The apparatus according to  claim 1 , wherein the sensor comprises a power source configured to power the sensor. 
     
     
         22 . The apparatus according to  claim 1 , wherein the sensor comprises a pressure transducer configured to measure depth in the borehole at which each measurement is performed. 
     
     
         23 . The apparatus according to  claim 1 , wherein the sensor is configured to sense at least one of temperature, pressure, density, viscosity, compressibility, acoustic property, magnetic property, chemical composition and material characteristic of the formation, fluid in the formation, drill string components, and drilling fluid. 
     
     
         24 . The apparatus according to  claim 1 , wherein the carrier is conveyed by a drill string or coiled tubing. 
     
     
         25 . A method for estimating a downhole property of interest, the method comprising:
 conveying a carrier through a borehole penetrating the earth;   releasing a sensor into drilling fluid;   sensing the property of interest using the sensor; and   downloading data sensed by the sensor at a location uphole from the sensing.   
     
     
         26 . The method according to  claim 25 , wherein downloading comprises retrieving the sensor from the drilling fluid or receiving transmitted sensed data from the sensor. 
     
     
         27 . The method according to  claim 25 , wherein the sensing is performed before the releasing. 
     
     
         28 . The method according to  claim 25 , wherein the sensor comprises a plurality of sensors. 
     
     
         29 . The method according to  claim 28 , wherein two or more sensors in the plurality are configured to sense a same property.