早在50年代初就发展了电流聚焦电阻的电缆测井仪,现已有点电极和屏蔽电极二种基本的电流聚焦测井仪。最近,勘探测井公司利用这种屏蔽电极的侧向测井原理,设计出电流聚焦电阻率随钻测井仪。仪器的测量电极及其上下的屏蔽电极之间用粗导线短路,使屏蔽电极和测量电极能维持一频率为1千赫兹的恒 As early as the early 1950s, current-focused resistance wireline tools have been developed. There are two basic current-focusing tools: point electrodes and shield electrodes. Recently, exploration logging companies used the lateral logging technique of shielded electrodes to design current-focus resistivity-while-drilling tools. The measuring electrode of the instrument and its upper and lower shielding electrodes are short-circuited with a thick wire so that the shielding electrode and the measuring electrode can maintain a constant frequency of 1 kHz