A measurement method to improve the quality of gamma spectrum data

Abstract

The invention discloses a data processing method using an inversion algorithm to improve the quality of the gamma energy spectrum in a nuclear logging tool. The method can effectively reduce the count of the Compton platform, and restore the gamma ray to the maximum extent when it is incident on the detector position. of energy. The data processing flow of this method is as follows: (1) Using the Monte Carlo simulation method, the response relationship matrix of the nuclear logging tool is established. (2) Save the gamma energy spectrum data measured by the logging tool containing the gamma detector in the form of a matrix. The energy spectrum data of each sampling point is a column in the matrix, and different sampling points are in different columns. (3) Perform preprocessing on the energy spectrum of each sampling point, such as energy correction, dead time correction, outlier elimination, etc., to ensure that the quality of the energy spectrum meets the requirements of subsequent processing; (4) use the detector response matrix in (1) to Perform inversion calculation on the energy spectrum data of each sampling point (5) obtain the gamma energy spectrum after inversion, and perform corresponding subsequent spectrum processing on the energy spectrum.

Description

[0001] Technical field: The invention belongs to the field of petroleum logging, and relates to a data processing method based on a data inversion method to improve the quality of the gamma spectrum in a nuclear logging instrument, thereby increasing the sensitivity and measurement accuracy of logging curve variables. Background technique: [0002] In the field of petroleum nuclear logging, whether it is natural gamma ray logging, density logging, lithology logging or logging tools using neutron sources, gamma detectors are used in these logging tools to detect gamma energy and Count to measure. Some of these logging tools require relatively high energy resolution of gamma detectors, such as full-energy spectrum logging in neutron-gamma logging tools, which need to calculate and analyze different elements in the formation through the measured gamma energy spectrum The content or ratio of the detector energy spectrum resolution will directly affect the accuracy of the measureme...

AI Technical Summary

Problems solved by technology

[0003] In conventional nuclear logging tools, due to the generally small diameter of the borehole, the sensitive volume of the gamma detector in the tool (such as the crystal size of the crystal detector) is usually limited by the internal space of the tool, which leads to Gamma rays cannot deposit all the energy in the sensitive region, resulting in fewer counts at the full energy peak position in the gamma ray spectrum and more counts on the Compton platform

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