Sensor and actuator for autonomously detecting wellbore fluids and closing fluid path

Abstract

A sensor device can be used to detect the presence of a cement composition in a reverse cementing operation. The sensor device can include a resistivity sensor, an acquisition and measurement apparatus, and an actuator. The actual resistivity of the drilling mud, spacer fluid, and cement composition to be used can be pre-determined. The acquisition and measurement apparatus can be pre-programmed with a resistivity profile for the fluids. The resistivity sensor can measure the resistivity of the fluids as they flow past the resistivity sensor in the wellbore. When the acquisition and measurement apparatus receives a desired reading within the resistivity profile, instructions can be sent to the actuator to close a valve and block fluid flow through the casing or tubing string.

What is claimed is: 
     
         1 . A method of detecting the presence of a cement composition in a reverse cementing operation in a wellbore comprising:
 introducing a sensor device into the wellbore, the sensor device comprising:
 a resistivity sensor configured to measure the resistivity of a fluid; 
 an acquisition and measurement apparatus configured to receive readings from the resistivity sensor; and 
 an actuator configured to receive instructions from the acquisition and measurement apparatus; 
   pre-programming the acquisition and measurement apparatus with a resistivity profile;   introducing a first fluid into the wellbore;   introducing a cement composition into an annulus of the wellbore;   allowing the resistivity sensor to measure the resistivity of the first fluid and the cement composition; and   allowing the acquisition and measurement apparatus to instruct the actuator to close a valve.   
     
     
         2 . The method according to  claim 1 , wherein the resistivity sensor comprises a source of electrical current, a voltage measurement system, electrodes, and cables. 
     
     
         3 . The method according to  claim 1 , wherein the acquisition and measurement apparatus is a controller board. 
     
     
         4 . The method according to  claim 1 , wherein the resistivity of the first fluid is different from the resistivity of the cement composition. 
     
     
         5 . The method according to  claim 1 , wherein the first fluid is a drilling mud or a spacer fluid. 
     
     
         6 . The method according to  claim 1 , further comprising introducing a second fluid into the wellbore, wherein the second fluid is introduced into the wellbore after the first fluid and before the cement composition, wherein the first fluid is a drilling mud, and wherein the second fluid is a spacer fluid. 
     
     
         7 . The method according to  claim 1 , further comprising pre-determining the resistivity for the first fluid and the cement composition prior to introduction of the sensor device into the wellbore. 
     
     
         8 . The method according to  claim 7 , wherein pre-determining the resistivity for the first fluid and the cement composition comprises: preparing a first and second test fluid, wherein the first test fluids is identical to the first fluid and the second test fluid is identical to the cement composition; and measuring the resistivity of the test fluids. 
     
     
         9 . The method according to  claim 7 , further comprising estimating the lengths of time that each of the first fluid and the cement composition flow past the resistivity sensor. 
     
     
         10 . The method according to  claim 9 , wherein the resistivity profile is determined based on the resistivity of the first test fluid and the second test fluid, and the lengths of time. 
     
     
         11 . The method according to  claim 1 , wherein the acquisition and measurement apparatus sends instructions to the actuator to close the valve after the acquisition and measurement apparatus receives a desired resistivity reading within the resistivity profile from the resistivity sensor. 
     
     
         12 . The method according to  claim 11 , wherein the desired resistivity reading corresponds to a pre-determined resistivity indicative of the cement composition in a concentration in a range from 20% to 100% by volume. 
     
     
         13 . The method according to  claim 11 , wherein the acquisition and measurement apparatus sends the instructions to the actuator to close the valve a desired period of time after receiving the desired resistivity reading from the resistivity sensor. 
     
     
         14 . The method according to  claim 1 , further comprising:
 introducing a second sensor into the wellbore, wherein the second sensor is located near the resistivity sensor, wherein the second sensor measures a property of the first fluid, the cement composition, or the first fluid and the cement composition;   pre-programming the acquisition and measurement apparatus with a profile of the property; and   allowing the second sensor to measure the property of the first fluid, the cement composition, or the first fluid and the cement composition.   
     
     
         15 . The method according to  claim 14 , wherein the property is a change in a magnetic field or capacitance. 
     
     
         16 . The method according to  claim 15 , wherein the second sensor is a magnetic sensor or a capacitance sensor. 
     
     
         17 . The method according to  claim 15 , wherein the first fluid or the cement composition comprises a magnetic mineral, or wherein the first fluid and the cement composition comprise a magnetic mineral in different concentrations. 
     
     
         18 . A reverse cementing sensor device comprising:
 a resistivity sensor, wherein the resistivity sensor is located on an inside of a casing string or tubing string;   an acquisition and measurement apparatus configured to be pre-programmed with a resistivity profile and to receive readings from the resistivity sensor; and   an actuator configured to receive instructions from the acquisition and measurement apparatus, wherein the acquisition and measurement apparatus is configured to send instructions to the actuator to close a valve located inside the casing string or tubing string after the acquisition and measurement apparatus receives a desired resistivity reading within the resistivity profile.   
     
     
         19 . A reverse cementing sensor device comprising:
 a first sensor located on an inside of a casing string or tubing string, wherein the first sensor is a resistivity sensor;   a second sensor located in the inside of the casing string or tubing string;   an acquisition and measurement apparatus configured to be pre-programmed with a profile corresponding to the first sensor and the second sensor, and configured to receive readings from the first sensor and the second sensor; and   an actuator configured to receive instructions from the acquisition and measurement apparatus, wherein the acquisition and measurement apparatus is configured to send instructions to the actuator to close a valve located inside the casing string or tubing string after the acquisition and measurement apparatus receives a desired reading within the profile for the first sensor, the second sensor, or the first sensor and the second sensor.   
     
     
         20 . The sensor device according to  claim 19 , wherein the second sensor is a magnetic sensor or a capacitance sensor.