Method and device for determining depth of instrument in well

Abstract

The invention relates to a method for determining depth of an instrument in a well. The method comprises the following steps (a) the instrument at one end of a cable is put into the well, and lengths of the cable stretching into the well at different time sampling points are recorded; (b) the accelerated speed of the instrument is measured, the accelerated speed is transmitted to a receiver at the other end of the cable, the receiver further receivers the recorded lengths of the cable stretching into the well, and a counter counts numbers of the time sampling points; (c) the received accelerated speed is corrected by selecting slidable time windows; (d) the movement speed of the instrument at the time sampling points of the selected time windows is calculated according to obtained data; (e) the depth of the instrument at the time sampling points of the selected time window in the well is determined through the obtained data; (f) the steps (c) to (e) are repeated until the number of the remaining time sampling points is smaller than n.

Description

technical field [0001] The present invention relates to a method of determining the depth of an object in a well, in particular, the present invention relates to a method and apparatus for determining the depth of an instrument in a well. Background technique [0002] In the well logging process, there are usually two ways to obtain the depth of the logging tool moving down the well at different times. The first way is to determine the length of the cable moving downhole by recording the wellhead; the second way The way is to make magnetic marks on the cable at equal intervals under constant tension, and the depth of the instrument in the downhole can be obtained by detecting the magnetic marks during the logging process. [0003] In practical applications, the first method is usually used to measure the depth of the logging tool in the well. During its operation, due to the elasticity of the cable, the logging tool will be subjected to various blocking effects in the downh...

AI Technical Summary

Problems solved by technology

[0005] This deviation affects the corresponding relationship between the geological information at the depth measured by the logging tool and the depth of the logging tool recorded by the cable in the well, so it is impossible to determine the depth of the logging tool in the downhole. Where is the information obtained about the porosity type and distribution of downhole rocks, the distribution of sand and mud and their correlations and other information really located in the downhole, which will bring great difficulties to subsequent operations and lead to a lot of waste in subsequent processing manpower and material resources

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