My guess is that they conducted a seismic survey. The results of the survey were obviously not encouraging or they would have pursued drilling a test well.
Seismic surveys are utilized to analyze the configuration of various rock layers to determine if they might be conducive to trapping oil. There is no tool for direct sensing of oil, so any claim that oil was positively identified without drilling a well should be completely ignored.
Extremely doubtful that Chevron would part with the survey for nothing. You could consult a seismic broker to see if they have made it available for purchase on the open market. Companies will often do that to recover part of the costs of their work after they have decided to move on.
Of course, then you would have to hire a Geophysicist to interpret it for you...