三维井壁中子—中子测井数值模拟

NUMERICAL SIMULATION OF THREE-DIMENSIONAL NEUTRON-NEUTRON WELL-LOGGING

应用多群P1近似和有限元方法对三维中子输运方程进行数值求解，并研究此方法在中子测井中的应用，实现了三维井壁中子—中子测井的数值正演研制了三维有限元中子测井软件包．应用它对江汉石油测井研究所的不同岩性的模型井进行了模拟计算，将计算结果同实验测量进行了比较，两者符合良好．用理论计算方法制作了各种环境校正图形曲线，计算精度令人满意．

In this paper the numerical simulation of fore-dimensional neutron-neutron well-logging is discussed. The netron transport equation is solved by finite element method with the multigroup P1 approximation and the direct numerical solution of neutron-neutron well-logging problem is acheived. Based on proposed model, a three-dimensional finite element code FEM3D is developed and appied to the numerical simulation of model wells with various lithologies in Jianghan Oil Well-logging Research Insihtute. The comparision of calculated results with measured results shows tha they are in qulte good agreement Using proposed numerical method,the environmental correction charts are established with satisfactory precision.