指向概率方法在中子伽马测井计算中的应用

APPLICATION OF DIRECTION PROBABILITY IN NEUTRON-GAMMA WELL LOGGING MEASUREMENT

应用蒙特卡罗方法,成功地模拟了中子伽马测井的物理过程和中子的输运过程、热中子的俘获以及中子伽马射线的产生和输运过程.用指向概率方法计算了中子伽马射线对探洲器的通量贡献,用群截面数据库模拟中子,用点截面数据模拟伽马光子,计算绘出的中子伽马能谱峰值与所选择的特征能量非常吻合,从而证明了蒙特卡罗方法在核测井领域应用的可行性.

Monte Carlo method was successfully used to simulate the physical process of neutron-gamma well logging including the emission and transport of neutrons, the capture of thermal neutrons, and the generation and transport of photons. The Neutron-gamma flux to the detector was calculated with a direction probability method. The multiple group neutron cross-section data were used in the transport of neutrons, and the point cross section data were used in the transport of photons. The calculated values of the photon energy peak were in good agreement with the selected value.