https://legacy.lib.utexas.edu/taro/txglo/00008/glo-00008.html
Access available to the public for free. Humble Oil Company and a consortium of other oil and gas exploratory companies commissioned Twichell to compile a record of surveys conducted between 1832 and 1984 in west Texas including Reeves county.
So, you see that Humble (now Exxon/Mobil) knew about the Delaware basin’s unique potential since the 1930s and conspired with others to sit on the information until the 1980s. The technology was not developed enough to exploit the stacked shale plays of the area until the 1980s.