DOWNHOLE DEVICE WITH TWO PROBES CONSISTING OF MULTIPLE DETECTORS Russian patent published in 2016 - IPC G01V5/10 

FIELD: physics.

SUBSTANCE: downhole device with two probes consisting of multiple detectors, which includes a housing inside of which there is at least one radiation source; the first one of the probes comprises more than one detector arranged uniformly on an angle along the periphery in a plane perpendicular to the axis of the downhole device; the second probe comprises at least one detector which is offset along the axis of the downhole device relative to the first probe and turned around the axis of the downhole device relative to the detectors of the first probe; the number of detectors in the second probe is not less than two; in each probe, detectors are arranged in parallel to the axis of the downhole device and detectors in probes are turned around the axis of the downhole device relative to each other such that the minimum angular distance φ between two adjacent projections of detectors from the first and second probes on a plane perpendicular to the axis of the downhole device is: φ=360×k/(2×N₁×N₂), where N₁ and N₂ are the number of detectors in the first and second probes, k is the least common denominator for the numbers N₁ and N₂.

EFFECT: reduced error in measuring radiation intensity due to the use of an optimum number and arrangement of detectors in case of axially symmetrical arrangement of the downhole device in the well.

3 dwg, 1 tbl