It’s all about the reservoir, a good reservoir engineer would be a good bet. Some areas are “known”, some, like yours are not, except for knowledge that a geologist could determine.
A lot of times some formations are “passed by” for the present but may be “viable” in the future. As your lease has expired, I recommend that you spend some to find out “real possibilities”. Hire a geologist to determine what you “May Have” and, if results are optimistic, find a reservoir engineer to verify “potential”. The cost for a geological evaluation would be the best initial option.
If your property was “leased” but not developed, it is an optimistic possibility that something could bear fruit in the future.