The principle of a digital ultrasonic imagery system applied mainly to the side wall in petroleum logging, the borehole instrumentation, the land facilities, the microcomputer image processing system as well as the logging results in cased well and bare well are described. 本文描述了一种主要用于石油测井的井壁数字超声成象系统,论述了井下仪器、地面设备和室内微机图象处理系统的工作原理,介绍了在测量裸眼井与套管井方面的应用效果。