Method for correcting depth trace of self-adapting well drilling

Abstract

The invention relates to a method for correcting the depth trace of self-adapting well drilling, in particular to a new method for correcting the well depth trace of the well drilling, which belongs to the technical field of measurement well drilling. The method comprises the following steps: firstly, obtaining correction coefficients (K1, K2, K3, ... Kn) according to the variations of coded disc counts and the variations of a drilling tool corresponding to each layer of wire ropes of a winch; secondly, training the correction coefficients with observed well depth, and dividing the variance of observed values and measured values into three regions, wherein each region corresponds to zero, big and small fuzzy numbers, and each fuzzy number corresponds to weighting coefficients k1, k2 and k3; and thirdly, counting the variations of the correction coefficients simultaneously to obtain the variation trend Va of the correction coefficients. The trained correction coefficients can make the variations of the correction coefficients automatically trend to influences on the correction coefficients by various factors; and the depth of the well drilling measured by the method trends to the precision gradually, the measuring errors are attenuated quickly, and the errors generated by initial depth correction and error corrections of the correction coefficients caused by introducing error observed values are eliminated effectively.

Description

Technical field: [0001] The invention relates to a method for self-adaptive correction of drilling depth, in particular to a method for correcting well depth tracking accuracy in the field of measurement while drilling. Background technique: [0002] In the field of oil drilling, it is necessary to accurately measure the depth of the well during the drilling process. The traditional method is to calibrate the relationship between the code disc count installed on the drilling winch and the depth of the drilling tool using experience or field calibration, determine one or a set of constant coefficients, and use this coefficient to correspond to the winch code disc count and drilling depth Relationships are tracked by the depth of the well. Its shortcoming is that it ignores that the depth correction coefficient is a set of correction coefficients that change with the change of wire rope tension (caused by factors such as suspension weight and drill string friction change). T...

AI Technical Summary

Problems solved by technology

Its shortcoming is that it ignores that the depth correction coefficient is a set of correction coefficients that change with the change of wire rope tension (caused by factors such as suspension weight and drill string friction change). The confirmed error and the drift of the correction coefficient make the measurement accuracy decrease continuously, and the measurement error increases cumulatively

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