Overhanging salt has been found on eleven coastal and interior domes in Texas and Louisiana. The first ledge of salt drilled through was at Belle Isle, Louisiana, in 1898; the first oil produced from formations beneath salt was found at Anse la Butte, Louisiana, in 1902. However, oil was not extensively and prolifically produced until discovery of the overhanging at Barbers Hill in 1930.
The general theories for the cause of overhangs are reviewed. The present criteria for the advance recognition of overhangs are listed, and the probability of other overhangs is conjectured. The special methods required for drilling through cap-rock cavities and salt are described.
The known overhangs are described and general and specific examples are shown by cross sections.
A tabulation shows wells drilled through salt overhangs.