Systems and methods for downhole resistance measurements
A system may convey a conveyance line including an electrical cable in a downhole environment. A system may measure a distributed electrical resistance of the electrical cable. A system may select a first point of the electrical cable. A system may, based on a first electrical resistance at the first point and a known initial electrical resistance, determine a first cable temperature of the electrical cable at the first point.
1 . A method of measuring temperature in a downhole environment, the method comprising:
conveying a conveyance line including an electrical cable in the downhole environment;
measuring a distributed electrical resistance of the electrical cable;
selecting a first point of the electrical cable;
based on a first electrical resistance at the first point and a known initial electrical resistance, determining a first cable temperature of the electrical cable at the first point;
selecting a second point of the electrical cable;
measuring an external temperature proximate to the second point;
based on a second electrical resistance at the second point and the known initial electrical resistance, determining a second cable temperature of the electrical cable at the second point;
determining a temperature offset based on the external temperature and the second cable temperature; and
adjusting the first cable temperature based on the temperature offset.
2 . The method of claim 1 , wherein measuring the distributed electrical resistance includes using time domain reflectometry.
3 . The method of claim 1 , wherein measuring the distributed electrical resistance includes using frequency domain reflectometry.
4 . The method of claim 1 , wherein measuring the distributed electrical resistance of the electrical cable is performed without stopping operations in the downhole environment.
5 . The method of claim 1 , wherein the second point of the electrical cable is a surface location of the electrical cable.
6 . The method of claim 1 , wherein the second point of the electrical cable is a downhole end of the electrical cable.
7 . The method of claim 1 , wherein the conveyance line is a coiled tubing line.
8 . A method of measuring temperature in a downhole environment, the method comprising:
conveying a conveyance line including an electrical cable in the downhole environment, wherein the electrical cable is a portion of a hybrid cable including an optical line;
measuring a distributed electrical resistance of the electrical cable;
selecting a first point of the electrical cable;
based on a first electrical resistance at the first point and a known initial electrical resistance, determining a first cable temperature of the electrical cable at the first point;
selecting a second point of the electrical cable;
measuring an optical temperature proximate to the second point;
based on a second electrical resistance at the second point and the known initial electrical resistance, determining a second cable temperature of the electrical cable at the first point;
determining a temperature offset based on the optical temperature and the second cable temperature; and
adjusting the first cable temperature based on the temperature offset.
9 . The method of claim 8 , wherein measuring the distributed electrical resistance includes using time domain reflectometry.
10 . The method of claim 8 , wherein measuring the distributed electrical resistance includes using frequency domain reflectometry.
11 . The method of claim 8 , wherein the conveyance line is a coiled tubing line.