针对海上油田中油基泥浆滤液侵入导致的储层核磁共振(Nuclear Magnetic Resonance,NMR)测井横向弛豫时间(Transverse Relaxation Time,T_(2))谱“拖尾”现象,提出了一种基于储层物性约束的T_(2)谱分段校正方法,并研发了可挂接于CIFLog...针对海上油田中油基泥浆滤液侵入导致的储层核磁共振(Nuclear Magnetic Resonance,NMR)测井横向弛豫时间(Transverse Relaxation Time,T_(2))谱“拖尾”现象,提出了一种基于储层物性约束的T_(2)谱分段校正方法,并研发了可挂接于CIFLog测井综合解释平台的插件模块。该方法以渗透率为校正判别阈值,按孔隙度分段构建多级物性区间,结合流体类型特征建立校正系数数据库,并在算法中引入积分面积守恒约束,确保校正前后T_(2)谱总面积一致,从物理层面保持孔隙度的真实性。模块采用插件化设计,实现了数据自动匹配、系数管理、计算可视化及结果输出等功能。南海北部湾盆地两口油基泥浆井的应用结果表明,校正后T_(2)谱“拖尾”现象得到明显抑制,长弛豫时间端幅值较原始T_(2)谱平均降低6.86%~10.61%,谱形与储层物性特征更加一致,测井解释结果与常规曲线及岩心资料匹配良好,验证了所建方法的稳定性与工程适用性。研究成果为复杂钻井条件下的核磁测井定量解释提供了可靠的技术支撑。展开更多
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 tec...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 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.展开更多
文摘针对海上油田中油基泥浆滤液侵入导致的储层核磁共振(Nuclear Magnetic Resonance,NMR)测井横向弛豫时间(Transverse Relaxation Time,T_(2))谱“拖尾”现象,提出了一种基于储层物性约束的T_(2)谱分段校正方法,并研发了可挂接于CIFLog测井综合解释平台的插件模块。该方法以渗透率为校正判别阈值,按孔隙度分段构建多级物性区间,结合流体类型特征建立校正系数数据库,并在算法中引入积分面积守恒约束,确保校正前后T_(2)谱总面积一致,从物理层面保持孔隙度的真实性。模块采用插件化设计,实现了数据自动匹配、系数管理、计算可视化及结果输出等功能。南海北部湾盆地两口油基泥浆井的应用结果表明,校正后T_(2)谱“拖尾”现象得到明显抑制,长弛豫时间端幅值较原始T_(2)谱平均降低6.86%~10.61%,谱形与储层物性特征更加一致,测井解释结果与常规曲线及岩心资料匹配良好,验证了所建方法的稳定性与工程适用性。研究成果为复杂钻井条件下的核磁测井定量解释提供了可靠的技术支撑。
基金supported by the National Natural Science Foundation of China(U23B20151 and 52171253).
文摘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 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.
