METHOD FOR AUTOMATIC CALIBRATION OF A DISTRIBUTED FIBER TEMPERATURE METER Russian patent published in 2023 - IPC G01K15/00 G01K11/32 E21B47/07 

FIELD: measuring technology.

SUBSTANCE: invention is related to equipment for measuring distributed temperature using optical fibre, and can be used to calibrate systems for measuring distributed temperature in long areas, in particular, such as oil and gas wells. A method for automatic calibration of a fibre distributed temperature meter is proposed, which includes the following steps: supplying power to thermostats installed on the ground section at the beginning of the optical fibre, and an active temperature sensor installed on the underground section at the end of the optical fibre; reading readings of thermostats, distributed temperature meter and active temperature sensor; correction of the readings of the distributed temperature meter of the ground section and correction of the readings of the distributed temperature meter of the underground section. The transmission of optical power from the optical transmitter to the active temperature sensor is carried out by means of an optical fibre, the transmission of a digital signal from the active temperature sensor to the digital data receiver is carried out by means of an optical fibre. The correction of the readings of the distributed temperature meter on the ground section is carried out using the following ratios: T₀₁ =T(γ₁, C₁, Z₀₁) and T₀₂ =T(γ₁,Δ₁, C₁, Z₀₂), where T₀₁ are temperature readings obtained on the first thermostat, T₀₂ - temperature readings obtained on the second thermostat, γ₁ - the value of the generalizing coefficient "scale", Δ₁ - the value of the generalizing coefficient "distance decrement", C₁ - the value of the generalizing coefficient "offset", Z₀₁ - the coordinate of the installation site of the first thermostat, Z₀₂ - the coordinate of the installation site of the second thermostat, by adjusting the values of the generalizing coefficients using the method of mathematical statistics in such a way that the minimum deviation of the calculated values from the values obtained on thermostats is reached. Correction of readings of the distributed temperature meter of the underground section (Z_x, Z₀₃) is carried out using the following ratios: T₀₃ =T(γ₁,Δ₂, C₁, Z ₀₃), where Δ₂ is the value of the generalizing coefficient "distance decrement" in the underground section, Z_x - the coordinate of the separation boundary between the underground and ground sections, set according to a priori information, Z₀₃ - the coordinate of the installation site of the active temperature sensor, by adjusting the values of the generalizing coefficients using the method of mathematical statistics in such a way so that the minimum deviation of the calculated values from the value obtained on the active temperature sensor is reached.

EFFECT: improvement of accuracy of temperature calibration of the measurement of distributed temperature on one fibre optic line.

8 cl, 2 dwg