Wireless run-in position sensing systems methods

Abstract

A method of performing real-time position sensing includes conveying a tool attached to a tubular string in a borehole. The tool includes a position sensing sub, and the position sensing sub includes sensing devices. The method further includes recording measurements taken by the sensing devices. The method further includes determining based on the measurements, a position along the borehole of a particular portion of the tubular string. Data from sensing devices having a higher priority overrides collecting data from sensing devices having a lower priority. The method further includes transmitting the position wirelessly.

1 . A method of performing real-time run-in position sensing comprising:
 conveying a tool attached to a tubular string in a borehole, wherein the tool comprises a position sensing sub, and wherein the position sensing sub comprises multiple sensing devices;   recording measurements taken by the sensing devices;   
       combining the measurements to determine a position along the borehole of a particular portion of the tubular string, wherein data from sensing devices having a higher priority overrides conflicting data from sensing devices having a lower priority; and
 transmitting the position wirelessly. 
 
     
     
         2 . The method of  claim 1 , wherein the sensing device with the highest priority comprises a radiation sensor that detects a radioactive tag. 
     
     
         3 . The method of  claim 1 , wherein the sensing devices comprise an accelerometer and a gyroscope. 
     
     
         4 . The method of  claim 1 , wherein the sensing devices comprise a roller counter. 
     
     
         5 . The method of  claim 4 , wherein the roller counter comprises wheels that turn as the tool is conveyed in the borehole, and wherein recording the measurements comprises determining the accuracy of the wheels. 
     
     
         6 . The method of  claim 5 , wherein determining the accuracy comprises determining the wheel that has turned the maximum number of times over a programmable distance along the borehole and recording that number as a measurement for use in position determination. 
     
     
         7 . The method of  claim 6 , comprising repeating the determining and recording over another programmable distance along the borehole. 
     
     
         8 . The method of  claim 1 , wherein the tubular string comprises perforation guns, and wherein determining the position comprises determining the position of the perforation guns. 
     
     
         9 . The method of  claim 8 , further comprising activating the perforation guns after determining the position without bringing the tool out of the borehole. 
     
     
         10 . The method of  claim 8 , wherein the tool is attached to the tubular string at a known distance from the perforation guns. 
     
     
         11 . The method of  claim 1 , wherein determining the position comprises determining the position of the position sensing sub. 
     
     
         12 . The method of  claim 1 , further comprising assembling the tubular string such that the position sensing sub resides below a packer and above perforation guns when within the borehole. 
     
     
         13 . The method of  claim 1 , wherein programmable events trigger position determination and updating of an error factor used to calibrate the position. 
     
     
         14 . The method of  claim 1 , wherein determining the position comprises determining the position repeatedly over programmable distances along the borehole. 
     
     
         15 . An apparatus for performing real-time run-in position sensing comprising:
 a hierarchy of sensing devices, wherein the sensing devices measure conditions within a borehole as the apparatus is conveyed along the borehole while attached to a tubular string;   a processor coupled to the sensing devices, wherein the processor determines position using data from the sensing devices, and wherein data from sensing devices having a higher priority overrides conflicting data from sensing devices having a lower priority during position determination; and   telemetry equipment coupled to the processor, wherein the telemetry equipment wirelessly communicates the position.   
     
     
         16 . The apparatus of  claim 15 , wherein the sensing devices further comprise a radiation sensor for detecting a radioactive tag, a roller counter, and a collar locator for detecting collars, and wherein the radiation sensor has the highest priority. 
     
     
         17 . The apparatus of  claim 15 , wherein the processor determines the position of the apparatus using the data from the sensing devices. 
     
     
         18 . The apparatus of  claim 15 , wherein the processor determines the position of perforation guns using the data from the sensing devices. 
     
     
         19 . The apparatus of  claim 15 , wherein programmable events, comprising detecting a radioactive tag or detecting a collar, trigger position determination. 
     
     
         20 . The apparatus of  claim 15 , wherein the sensing devices comprise an accelerometer, pressure sensor, and gyroscope.