通过介绍数字平板探测器的基本组成及特点,利用射线成像系统的基本理论,根据工业DR/CT系统的调制传递函数(modulation transfer function简称MTF),并对该函数进行进一步推导,结合平板探测器的特点,完成了成像系统的优化设计,并得到了较...通过介绍数字平板探测器的基本组成及特点,利用射线成像系统的基本理论,根据工业DR/CT系统的调制传递函数(modulation transfer function简称MTF),并对该函数进行进一步推导,结合平板探测器的特点,完成了成像系统的优化设计,并得到了较好的成像效果。实际系统设计表明,该方法具有通用性。展开更多
Three dimensional geophysical models were abstracted and established according to characteristics of oil and gas reservoir.Then direct current fields for different models were simulated with finite element software(fi...Three dimensional geophysical models were abstracted and established according to characteristics of oil and gas reservoir.Then direct current fields for different models were simulated with finite element software(finite element program generator) by hole-to-surface resistivity method.Numerical solution was compared with analytical one for the homogeneity earth model.And a new parameter of deviation rate was proposed by analyzing different plot curves.The results show that the relative error of solution for homogeneity earth model may attain to 0.043%.And deviation rate decreases from 18% to 1% and its anomaly range becomes wide gradually when the depth of oil and gas reservoir increases from 200 to 1 500 m.If resistivity ratio of oil and gas reservoir to sur-rounding rock decreases from 100 to 10 for the resistive oil and gas reservoir,the amplitude attenuation of deviation rate nearly reaches 8%.When there exists stratum above oil and gas reservoir,and influence of resistive stratum may be eliminated or weakened and anomaly of oil and gas reservoir can be strengthened.展开更多
文摘通过介绍数字平板探测器的基本组成及特点,利用射线成像系统的基本理论,根据工业DR/CT系统的调制传递函数(modulation transfer function简称MTF),并对该函数进行进一步推导,结合平板探测器的特点,完成了成像系统的优化设计,并得到了较好的成像效果。实际系统设计表明,该方法具有通用性。
基金Projects(2006AA06Z105,2007AA06Z134) supported by the National High-Tech Research and Development Program of China
文摘Three dimensional geophysical models were abstracted and established according to characteristics of oil and gas reservoir.Then direct current fields for different models were simulated with finite element software(finite element program generator) by hole-to-surface resistivity method.Numerical solution was compared with analytical one for the homogeneity earth model.And a new parameter of deviation rate was proposed by analyzing different plot curves.The results show that the relative error of solution for homogeneity earth model may attain to 0.043%.And deviation rate decreases from 18% to 1% and its anomaly range becomes wide gradually when the depth of oil and gas reservoir increases from 200 to 1 500 m.If resistivity ratio of oil and gas reservoir to sur-rounding rock decreases from 100 to 10 for the resistive oil and gas reservoir,the amplitude attenuation of deviation rate nearly reaches 8%.When there exists stratum above oil and gas reservoir,and influence of resistive stratum may be eliminated or weakened and anomaly of oil and gas reservoir can be strengthened.
