The Amoco Array Sonic Logger

Solo, the Amoco array sonic logger, consists of an array tool with a single magnetostrictive transmitter and eight piezoelectric receivers, and an uphole system built around a microcomputer using an 8 MHz Motorola 68000 processor. The processing algorithm used to extract compressional and shear speeds from the recorded time series is robust and sufficiently efficient that the data can be processed on the microcomputer as logging proceeds. The algorithm is based on an nth-root slant stack and is described in considerable detail. The product of the processing algorithm is a scalar function of slowness that depicts the slownesses at which events were detected traversing the receiver array. Displays that show this function together with time series that produced it are called packet plots. Displays that show ensembles of these functions over a range of depths are called waterfall plots. Both of these types of plots are useful diagnostic tools.