球形聚焦测井的数字聚焦方法

数字聚焦方法与球形聚焦不同。球形聚焦通过电极系采用硬件控制方法实现动态聚焦，数字聚焦通过电极系采用软件虚拟聚焦交替发射测量电流和屏蔽电流，分时间记录各种基本测量值，根据基本测量值按聚焦条件下的电阻率计算公式求出A0电极附近地层电阻率。数字聚焦测井的电极系尺寸及分层能力与球形聚焦测井相同，数字聚焦仪器电路简单，调试维修方便。

A Digital Focusing Approach to Spherically Focused Log

Digitally focused log method is different from spherically focuced log method. The latter uses hardware control for dynamic focusing through electrodes, while the former uses software virtual focucing in alternatively sending measuring and bucking currents through the electrodes and, also records various basic measurements in different time. According to the basic measurements, resistivity formula under the focusing condition is used to obtain formation resistivity near the electrode A 0.Digitally focused log method has the same electrode size and zonation ability as the spherically focused log method. Circuits in the digitally focused logging tool are simple, and easy in maintenance.