Research Of The Well-Depth Measure Of High Resolution With Magnetic Marks

Depth is one of the most important basic data for oil well to calculate various stratum layer parameters, Whether the depth that well parameter measuring instruments are laid down is accurately record, will have a direct influence on the collection and analysis of various test data. The way that combining Mardingdack method and Cable magnetic mark method to ensure the accuracy of the oil layer depth measurement, is widely used in existing measuring method. However, in practical application, meter wheel will be worn out and become skid when long-term used, due to the machinery transmission characteristic of mardingdack method. Furthermore, meter wheel will skid and influence measurement accuracy when used in winter because of cable icing as well. And cable magnetic mark method has a problem that resolution can not satisfy the measurement requirements when used alone.This paper designs a well depth measuring method with high resolution based on cable magnetic mark method. It records the large number of well depth through the count survey of cable magnetic mark, and then calculates the relative displacement of each magnetic mark point through measuring the real-time speed and relative time of cable by applying correlation measurement of the velocity method. By doing so, subdivision of two magnetic mark point distance is achieved, and a high resolution is obtained. Meanwhile, the well-depth measuring method of high resolution with magnetic mark is discussed in the paper, as well as the feasibility of correlation measurement of the velocity. This paper designs the system project of well depth measuring, finishes the magnetizer and demagnetizer design, DSP signal acquisition and processing circuit design. And lastly, the system software is developed.The measuring method used in this system not only avoids meter wheel skidding in mardingdack method, but also overcomes the shortcoming of low resolution to cable magnetic mark method when used alone, and fulfills the resolution requirement in well depth measuring.Due to applying pulsed magnetic-field charge magnetism and demagnetization and DSP processor, it has the advantages of miniaturization, easy to carry and suitable for use.