过钻具小直径阵列侧向测井响应及倾斜各向异性分析

针对过钻具测井，研究小直径阵列侧向测井技术。确定电极系尺寸结构，利用数值模拟方法研究小直径电极系的井眼、围岩、侵入响应特征，与常规大直径电极系的响应进行对比分析。研究小直径电极系在斜井、水平井中的响应特征，分析井眼倾角、地层电阻率各向异性的影响规律，制作交会图版。结果表明，针对小直径电极系，需重新制作井眼影响图版，围岩、侵入响应特征与常规大直径电极系基本相同。随着井眼倾角、各向异性系数增加，视电阻率增大，曲线分离以60°倾角为界，分别呈现出高侵、低侵特征。利用视电阻率比值和均值可以做出地层水平电阻率和各向异性系数的交会图版。为过钻具小直径阵列侧向测井技术的发展及其斜井、水平井解释评价提供依据。

Small-diameter array laterolog response through bit logging and inclined anisotropic formation analysis

Small-diameter array laterolog technology is studied for through bit logging. The size structure of the electrode sonde is determined, and the borehole, surrounding rock and invasion response characteristics of the small diameter electrode sonde are studied by the numerical simulation method, compared with the response of the conventional large-diameter electrode sonde. The response characteristics of small-diameter electrode sonde in inclined and horizontal well are studied, and the influence of deviated angle and formation resistivity anisotropy is analyzed. The results show that for the small-diameter electrode sonde, the borehole influence chart needs to be remade, and the response characteristics of surrounding rock and invasion are basically the same as those of the conventional large-diameter electrode sonde. With the increase of deviated angle and anisotropy coefficient, the apparent resistivity increases, and the curve separation is bounded by 60° angle, showing the characteristics of high and low invasion respectively. The cross chart of horizontal resistivity and anisotropy coefficient can be made by using the ratio and mean value of apparent resistivity. It provides a foundation for the development of small-diameter array laterolog technology and the interpretation and evaluation of deviated and horizontal wells.