A Method for Obtaining Neutron Capture Gamma Spectrum in Element Logging

Abstract

The invention discloses an element logging neutron capture gamma-ray energy spectrum obtaining method. The method is characterized by measuring gamma-ray energy spectrum under a laboratory condition and carrying out analysis, and determining energy resolution of a detector; according to formation element capture gamma-ray spectrum logging instrument parameters, establishing a model; simulating thermal neutron capture gamma-ray energy spectrum under a well of a formation element capture gamma-ray spectrum logging instrument through a Monte-Carlo method; and carrying out processing and analysis of single element gamma-ray energy spectrum obtained through simulation to determine a single element simulated spectrum of some element. The beneficial effects are that the method realizes modeling for an ECS logger in the formation element logging technology, and obtains the single element simulated spectrum of some element, thereby providing important technical support for data processing of the ECS logger.

Description

technical field [0001] The invention belongs to the technical field of geophysical well logging, and relates to a method for obtaining neutron capture gamma energy spectrum of element well logging. Background technique [0002] The element capture spectroscopy logging tool (ECS for short) uses 241 Am- 9 The Be neutron source emits neutrons with an energy spectrum ranging from 0 to 10 MeV. In the interaction process of neutrons and formation materials, it can be mainly divided into two stages: neutron moderation stage and neutron absorption stage. The data detection system detects the gamma rays emitted by these two stages. During neutron moderation, only inelastic scattering can emit gamma rays. In the neutron absorption stage, thermal neutrons and atomic nuclei capture reactions can emit gamma rays. When a capture reaction occurs, neutrons are absorbed by the target nucleus to form a composite nucleus, and then the composite nucleus returns to the ground state by emitt...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for obtaining the neutron capture gamma energy spectrum of element logging, which solves the problem that there is no standard well established for single elements in China, so the standard spectrum cannot be obtained through actual instrument measurement, thus restricting the domestic Research and development of related instruments and practical application in oil field

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