井壁超热中子测井MC模拟

在 MCNP的基础上 ,开发了井壁超热中子时间谱测井蒙特卡罗 (Monte Carlo)模拟软件包 .裸眼井、井眼里无下井仪器、淡水饱和砂岩地层、井眼注淡水 ;油饱和砂岩地层、井眼注油 ;油饱和砂岩地层、井眼注淡水 ;淡水饱和灰岩地层、井眼注淡水与淡水饱和白云岩地层、井眼注淡水 ,及裸眼井、井眼里有下井仪器、淡水饱和砂岩地层、井眼注淡水等条件下 ,计算井壁超热中子时间谱随孔隙度的变化 ,同时可得到井壁超热中子总通量随孔隙度的变化 ,结果证明井壁超热中子时间谱测井或井壁超热中子测井是确定地层孔隙度最有效的方法 .在此基础上 ,再研究井壁超热中子时间谱测井仪或井壁超热中子测井仪的工程参数 .

MC Calculation of Wall Epithermal Neutron Logging

The Monte Carlo calculating software packet was developed for wall epithermal neutron time spectrometry logging on the basis of MCNP. The wall epithermal neutron time spectra of simulated open holes were calculated, which vary with the porosity of formation. Three simulated open holes were drilled in fresh water saturated sandstone, limestone and dolostone formations separately, and there is not downhole instrument in the boreholes filled with fresh water; two ones were drilled in oil saturated sandstone formation, there is not downhole instrument in the boreholes filled with oil and fresh water separately; one was drilled in fresh water saturated sandstone formation, there is downhole instrument in the borehole filled with fresh water. It was verified that the epithermal neutron time spectrometry logging or the epithermal neutron logging is the most effective method. The engineering parameters of the instrument were calculated.