A Method for Peak Stabilization of 2228 Lithology Density Logging Tool with Short Source Spacing Detector

Abstract

The invention discloses a method for peak stabilizing of a short spaced detector of a 2228 litho-density tool. A 0.25 microcurie exemption cesium source is added to the short spaced detector, and the exemption cesium source is attached to the short spaced detector tightly and used for monitoring the stability and reliability of peak stabilizing work of the short spaced detector. According to the method, on the basis of the traditional process, a cesium-free source structure of the short spaced detector is mainly changed. The short spaced detector with the exemption cesium source provides effective conversion collected data for the ground through automatic spectrum stabilization in the signal processing process, the thermal resistance of a temperature-compensation circuit does not need to be adjusted, thus the problems that the short spaced detector is influenced greatly by the downhole temperature and consequently the repeatability of logging information exceeds the standard are avoided, thus the tool logging success rate can be increased effectively, and logging quality can be improved effectively.

Description

technical field [0001] The invention relates to a method for stabilizing a peak of a well logging instrument in the technical field of petroleum well logging, in particular to a method for stabilizing a peak of a short source distance detector of a 2228 lithology density logging instrument. Background technique [0002] With the intensification of oilfield exploration and development tasks and the secondary development of oilfields, many oilfield companies require the use of lithology density measurement methods, not only to measure the density value of formation materials, but also to measure the photoelectric absorption Pe value of the formation for better analysis Formation lithology. At present, the density downhole tool used by the logging company is mainly the 2228 lithology density logging tool imported from Atlas Company. The 256 energy spectrums counted by the detectors and the counts of the short source distance detectors are transmitted to the surface numerical c...

AI Technical Summary

Problems solved by technology

In the logging process of 2228 lithology density logging tool, ground software is used to control the cesium source peak stabilization device of the downhole instrument in the long source distance, and the thermistor is used to control the high voltage to adjust the output amplitude of the photomultiplier tube in the short source distance. increase, its technical performance gradually declines, and at the same time, it is found that the short source spacing is greatly affected by the downhole temperature in logging applications, resulting in the repeatability of logging data exceeding the standard

[0013] (1) For the instrument using the thermistor method, the counting rate will change greatly during the heating process (25°C-175°C). The measured counting rate changes between (4490.4--3881.7) CPS, and the counting rate drops trend (unstable)

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