Scholarlink

<p>Although traditional gamma-gamma density (GGD) logging technology is widely utilized, its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density (NGD) logging technology. However, NGD measurements are influenced by both neutron and gamma radiations. In the logging environment, variations in the formation composition indicate different elemental compositions, which affect the neutron-gamma reaction cross-sections and gamma generation. Compared to traditional gamma sources such as Cs-137, these changes significantly affect the generation and transport of neutron-induced inelastic gamma rays and hinder accurate measurements. To address this, a novel method is proposed that incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation, thereby achieving more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energies and spatial distributions in varied logging environments. The proposed method avoids the complex correction of neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents, demonstrating absolute density errors that are less than <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(0.02\,\hbox {g/cm}^3\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>0.02</mn> <mspace width="0.166667em" /> <msup> <mtext>g/cm</mtext> <mn>3</mn> </msup> </mrow> </math></EquationSource> </InlineEquation> in clean formations and indicating good accuracy. This study clarifies the NGD mechanism and provides theoretical guidance for the application of NGD logging methods. Further studies will be conducted on extreme environmental conditions and tool calibration.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Neutron-gamma density measurement method using the mass attenuation coefficient function

  • 期刊论文

  • 发表日期：

    2025年12月6日

查看全文
  • Jun-Yan Chen,
  • Qiong Zhang

摘要

Although traditional gamma-gamma density (GGD) logging technology is widely utilized, its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density (NGD) logging technology. However, NGD measurements are influenced by both neutron and gamma radiations. In the logging environment, variations in the formation composition indicate different elemental compositions, which affect the neutron-gamma reaction cross-sections and gamma generation. Compared to traditional gamma sources such as Cs-137, these changes significantly affect the generation and transport of neutron-induced inelastic gamma rays and hinder accurate measurements. To address this, a novel method is proposed that incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation, thereby achieving more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energies and spatial distributions in varied logging environments. The proposed method avoids the complex correction of neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents, demonstrating absolute density errors that are less than \(0.02\,\hbox {g/cm}^3\) 0.02 g/cm 3 in clean formations and indicating good accuracy. This study clarifies the NGD mechanism and provides theoretical guidance for the application of NGD logging methods. Further studies will be conducted on extreme environmental conditions and tool calibration.