FIELD: measurement equipment.
SUBSTANCE: invention relates to the field of geophysical survey of oil and gas wells and may be used to measure depth of downhole tools submersion. Previously geophysical cable is measured, and magnetic marks are applied onto cable armour in identical sections. Simultaneously outer layers of cable armour are counted, and their number from the point of cable connection to downhole tool and further to each subsequent magnetic mark is memorised. In process of geophysical survey as cable travels up and down, magnetic marks are discovered and counted. Simultaneously outer layers of cable armour are counted, and their number is compared to according memorised values. Obtained data is used to detect depth of downhole tool submersion and to apply magnetic marks in areas, where they have not been discovered on cable armour.
EFFECT: increased accuracy of measurement of depth of tool submersion into well, independently on effect of magnetic noise in well.
1 dwg
