Rock debris gamma-ray energy spectrum unfolding method and system based on genetic algorithm

Abstract

The invention discloses a rock debris gamma-ray spectrum unfolding method and system based on a genetic algorithm. The rock debris gamma-ray spectrum unfolding method comprises the steps that: a gamma-ray spectrogram obtained by conducting gamma-ray spectrum measurement on an environment background, a plurality of standard samples and an actual rock debris sample is obtained; forward modeling calculation is carried out according to energy spectrum values in the gamma-ray energy spectra of the environmental background and the standard sample to obtain a synthetic gamma-ray energy spectrum; by utilizing the measured gamma-ray energy spectrum of the actual rock debris sample and a synthetic gamma-ray energy spectrum obtained through forward modeling calculation, establishing an objective function of a spectrum unfolding problem; and carrying out optimal solution on the established target function by adopting a genetic algorithm so as to obtain the content of each radionuclide in the actual rock debris sample. The method can deal with the problem of large errors of the spectrum unfolding algorithm of the traditional characteristic peaks, and the spectrum unfolding effect is greatly improved.

Description

technical field

[0001] The invention relates to the field of oil and gas development and exploration, in particular to a method and system for deciphering the gamma energy spectrum of cuttings by using a genetic algorithm. Background technique

[0002] During the drilling process, the cuttings broken by the drill bit at the bottom of the well are continuously returned to the ground along with the circulation of the drilling fluid. Cuttings are intuitive materials for understanding formation lithology and oil and gas layers in a timely manner, and are also reliable empirical data for studying downhole geological conditions, evaluating source-reservoir-cap associations, and effectively finding industrial oil layers. Conventional cuttings logging uses naked eye or microscope geological observation, combined with instrument analysis, to describe and name, determine the rock type at the sampling depth, identify downhole formation lithology and oil and gas, and make downhole cutti...

Examples

Embodiment 1

[0034] figure 1 It is a schematic flow chart of the method for deciphering the gamma spectrum of cuttings based on genetic algorithm in the embodiment of the present application. Refer below figure 1 To illustrate each step of this method.

[0035] First, in step S110 (gamma energy spectrum acquisition step), the gamma energy spectrum obtained by measuring the gamma energy spectrum of the environmental background, multiple standard samples and actual rock debris samples is obtained, wherein each standard The samples contained different pure radionuclides.

[0036] "Environmental background" refers to the baseline content of chemical elements or chemical substances in various environmental elements when the natural environment is not polluted, that is, the environmental state before human activities interfere.

[0037]In a preferred example, the multiple standard samples include three standard samples containing pure radionuclides U, TH and K. The so-called "pure radionuclid...

Embodiment 2

[0073] Figure 4 It is a schematic structural diagram of a genetic algorithm-based cutting gamma spectrum deciphering system 40 according to an embodiment of the present application. Refer below Figure 4 The various parts that make up the system 40 will now be described.

[0074] like Figure 4 As shown, the system 40 includes a gamma energy spectrum acquisition module 42 , a total energy spectrum calculation module 44 , an objective function establishment module 46 and an objective function solution module 48 .

[0075] Gamma energy spectrum acquisition module 42, which acquires the gamma energy spectrum obtained by measuring the gamma energy spectrum of the environmental background, multiple standard samples and actual rock chip samples, wherein each standard sample contains different pure radioactive Nuclides.

[0076] The total energy spectrum calculation module 44 is used for forward calculation to obtain a synthetic gamma energy spectrum according to the environment...

technical field

[0001] The invention relates to the field of oil and gas development and exploration, in particular to a method and system for deciphering the gamma energy spectrum of cuttings by using a genetic algorithm. Background technique

[0002] During the drilling process, the cuttings broken by the drill bit at the bottom of the well are continuously returned to the ground along with the circulation of the drilling fluid. Cuttings are intuitive materials for understanding formation lithology and oil and gas layers in a timely manner, and are also reliable empirical data for studying downhole geological conditions, evaluating source-reservoir-cap associations, and effectively finding industrial oil layers. Conventional cuttings logging uses naked eye or microscope geological observation, combined with instrument analysis, to describe and name, determine the rock type at the sampling depth, identify downhole formation lithology and oil and gas, and make downhole cutti...

Examples

Embodiment 1

[0034] figure 1 It is a schematic flow chart of the method for deciphering the gamma spectrum of cuttings based on genetic algorithm in the embodiment of the present application. Refer below figure 1 To illustrate each step of this method.

[0035] First, in step S110 (gamma energy spectrum acquisition step), the gamma energy spectrum obtained by measuring the gamma energy spectrum of the environmental background, multiple standard samples and actual rock debris samples is obtained, wherein each standard The samples contained different pure radionuclides.

[0036] "Environmental background" refers to the baseline content of chemical elements or chemical substances in various environmental elements when the natural environment is not polluted, that is, the environmental state before human activities interfere.

[0037]In a preferred example, the multiple standard samples include three standard samples containing pure radionuclides U, TH and K. The so-called "pure radionuclid...

Embodiment 2

[0073] Figure 4 It is a schematic structural diagram of a genetic algorithm-based cutting gamma spectrum deciphering system 40 according to an embodiment of the present application. Refer below Figure 4 The various parts that make up the system 40 will now be described.

[0074] like Figure 4 As shown, the system 40 includes a gamma energy spectrum acquisition module 42 , a total energy spectrum calculation module 44 , an objective function establishment module 46 and an objective function solution module 48 .

[0075] Gamma energy spectrum acquisition module 42, which acquires the gamma energy spectrum obtained by measuring the gamma energy spectrum of the environmental background, multiple standard samples and actual rock chip samples, wherein each standard sample contains different pure radioactive Nuclides.

[0076] The total energy spectrum calculation module 44 is used for forward calculation to obtain a synthetic gamma energy spectrum according to the environment...

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