This is a well log used in the oil and gas industry. The acronym
ISTA is a unique identifier to recognize this particular log and can be encountered in your log evaluation software or your corporate datastores. The full name for this log used in the industry is
'Sonic Time of Acquisition'. This log is not often acquired after (or during) drilling a well. This log can be used to evaluate the time value which is associated with some event to fix its occurrence in time; often expressed as an elapsed time from recent reference time. At a higher level, this can be seen as a measure of the absolute time. In other words, the time value which is intended to fix an event in time, such as a geological time, a date, or the start time of a process.This log usually has the unit
'Time'. This is the 1) The measured or measurable period during which an action, process, or condition exists or continues. 2) The point or period when something occurs. 3) A fixed moment or hour for something to happen, begin, or end. 4) A historical period.
Data from this log can be used to investigate the time instant. Similar logs are listed below:
