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补偿中子测井(CNL)也是一种孔隙度测井方法。在中子测井中,井径的变化是一个重要的影响因素。井径扩大会引起假的高孔隙度显示。井壁中子测井与普通中子测井相比,井眼的影响已经大大减小,但仍需进行井眼校正。在地层不均匀的情况下,根据井壁中子测井结果确定孔隙度,误差较大。为了进一步减小井径变化和地层不均匀的影响,采用一种双探测器的中子测井仪,这就是补偿中子测井仪。补偿中子测井仪可同时测量长、短源距两种计数率。这两种计数率的比值与孔隙度呈一定的函数关系,因此可在地面面板中换算成孔隙度值,并以线性比例尺记录下来。
Compensated Neutron Logging (CNL) is also a porosity logging method. In neutron logging, the variation of borehole diameter is an important factor. Caliper expansion causes fake high-porosity displays. Wellbore neutron logging Compared with normal neutron logging, the impact of the wellbore has been greatly reduced, but borehole correction is still required. In the case of uneven strata, porosity is determined from the borehole neutron well logging results with large errors. In order to further reduce the influence of borehole diameter variation and formation heterogeneity, a dual-detector neutron tool is used, which is a compensated neutron tool. Compensated neutron tool can measure both long and short source count rates. The ratio between these two counts is a function of porosity and can therefore be converted to a porosity value in the ground plane and recorded on a linear scale.