DOWNHOLE INSTRUMENT FOR MEASURING TEMPERATURE OF INNER SURFACE OF CASING STRING Russian patent published in 2024 - IPC E21B47/07 

FIELD: measurement; oil industry.

SUBSTANCE: invention relates to geophysical surveys of operating oil wells. Downhole instrument for measuring temperature of inner surface of casing metal string comprises cylindrical sealed metal housing, spring-loaded lever centralizer in head and tail parts of the device housing and temperature sensors arranged on hold-down levers of both centralisers and uniformly distributed along the circumference of the wellbore cross-section. Induction heater is additionally introduced into the downhole instrument, which is connected to the housing of the instrument and is located between the centralisers. In the eye of the hold-down levers adjoining the spring-loaded mechanism for opening/closing the centralizer there is a measuring lever with a temperature sensor. Temperature sensor comprises housing with flat heat receiver. Temperature sensor is embedded in the measuring arm on a section adjoining the eye with length of 0.15–0.2 of the total length of the measuring arm so that the outer surface of the housing and the heat receiver protrudes outside. Outer surface of the housing and the heat receiver is made flush, has a slope towards the eye of the measuring lever of 5–15% with the largest projection from the outer surface of the measuring lever of centralizer by 1–3 mm and a radius of curvature.

EFFECT: wider field of use of the downhole tool and obtaining reliable information on the temperature of the inner surface of the metal casing.

1 cl, 6 dwg