Extensive oil exploration work carried out by Delhi Australian Petroleum Ltd and Santos Ltd in the central portion of the Great Australian Artesian Basin since 1957 led to the discovery of the Gidgealpa Gas Field in north-easternmost South Australia in late 1963. Exploration work responsible for the discovery of the Gidgealpa Field consisted of geological surface investigations, extensive airborne magnetometer surveys, and reflection and refraction seismograph surveys. Eight dry wildcat exploratory holes had been drilled prior to the discovery of the field. Prior to the commencement of this exploration programme, virtually nothing was known about the sub-surface geology of those parts of the Great Australian Artesian Basin present below the Mesozoic artesian aquifer. Zealous exploration progressively established the basic data which ultimately led to success. Five gas producing wells have been completed, with a total flow capacity of 62.5 MMCFD through a ½ inch choke.