Gamma-gamma density logging distorted curve correction method

Abstract

The invention belongs to the field of nuclear physics research and application, and specifically relates to a gamma-gamma density logging distorted curve correction method. The invention provides a correction method for eliminating gamma-gamma density logging curve distortion produced due to rock radiation in the stage of gamma-gamma density logging data sorting. The method comprises the following steps: S1, selecting a correction depth section; S2, calculating the density value of a rock skeleton; S3, calculating the average correction coefficient value; and S4, calculating the rock density of the correction depth section and drawing a corrected gamma-gamma density curve. The problem that a curve fluctuates drastically in a uranium enrichment section before correction is solved. Accurate acoustic impedance data can be provided for seismic exploration, and the quality of gamma-gamma density logging can be monitored effectively. The correction method is also applicable to a gamma-gamma density logging distorted curve affected by a hole enlarge section and a hole collapse section.

Description

technical field [0001] The invention belongs to the field of nuclear physics research and application, and is a method for correcting the distortion of the collected information caused by the interference of radioactive factors in the nuclear logging. Background technique [0002] γ-γ density logging technology is an expansion of nuclear physics research and application field. It mainly obtains downhole formation density information and technical parameters through the Compton scattering effect produced by artificial radionuclides and rock formations in the wellbore. [0003] From the interaction between γ-rays and matter, when the energy of γ-rays is between 0.25MeV and 2.5MeV, in the medium of light elements, the total attenuation coefficient (μ) can be characterized as [0004] μ≈μ K ≈0.5σ e Nρ…………………………(1) [0005] where μ K — Compton attenuation coefficient; σ e —Scattering cross section of gamma ray to each electron; N—Avogadro constant; ρ—density of interacting s...

AI Technical Summary

Problems solved by technology

The currently implemented method is real-time ore core sampling. Under field conditions, this time-consuming and laborious method is difficult to measure the density and humidity of ore accurately, because rocks with good permeability have poor water holding capacity, and after the core is taken out of the borehole, it is difficult to accurately measure the density and humidity of the ore. The water contained in the pores will be partially lost, making it difficult to measure the humidity

If the γ-γ density curve is not disturbed and the water saturation of the ore core is known, the humidity of the ore can be obtained by relying on the measured ore dry density and γ-γ density value, which is used to check the error of the measured humidity and carry out Reasonable correction, but the disturbed gamma-gamma density curve loses the reference standard

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