小井径双源距C/O测井响应随源距的变化关系

A study on the relationship between response of C/O log and spacing

应用Monte Carlo方法,在孔隙度分别为5%、10%、20%和35%的砂岩地层中,针对地层孔隙流体分别为油和水,井内介质分别为油和水的4种情况,计算得到了C/O测井响应随源距的变化关系以及不同源距时,C/O测井对地层径向厚度的响应.通过数据处理,得到地层相同,井内介质不同时C/O差值随源距的变化关系,以及井内介质相同,地层不同时的C/O差值随源距的变化关系.通过比较分析,得出小井径双源距C/O能谱测井响应对源距有很强的依赖性;当源距的范围在26～34cm和50～62cm之间时,C/O测井分层能力强,同时受井眼影响小,因此,短源距的选择范围是26～34cm,长源距的选择范围是50～62cm.

It helps to offer spacing parameters in optimizing dual-detector C/O logging tool in slim holeto investigatethe relationship between response of （C/O log and spacing in slim hole with numerical simulation. By Monte Carlo method, the responses of C/O log with different spacingare simulated for four kinds of condition, such as water or oil in the well, and water or oil in theporosity in the formation with the porosity of 5%, 10%, 20% and 35%, and the paper simulates the C/O responses for radial thickness with different spacing simultaneously. Thepaper obtains the difference of C/O with different spacing forthe same formation, different borehole material and the same borehole material, different formation after data processed. By comparing and analyzing the calculation results mentioned above, the paper concludes that the responses of C/O log are dependent on spacinggreatly, and C/O log has better distinguishing power for formation with less influence of borehole when spacing is between 27cm and 34cm or between50cm and 63cm. Therefore, the optimal long spacing of （C/O logging tool in slim hole is between 50cm and 62cm, and the optimal short spacing is between 26cm and 34cm.