Get a lawyer to negotiate any lease. Do not sell. The Delaware Basin has multiple layers of petroleum deposits. The United States Geological Service has doubled, and in some places tripled, the estimated amount of Oil In Place within the Delaware Basin portion of the Permian Basin. The recovery rate, that is the amount of oil that can be extracted has increased to 20%. The technology for extraction keeps increasing the recovery rate. The oil produced is easily refined and desired.
The large problem is that the infrastructure for supporting the extraction and the transport of the oil and gas and liquids is still being built out.
In some areas, the royalty value of an acre over a lifetime of production of thirty years, based on the current methods and efficiencies, ranges from $400,000 to more. The thickness of oil and gas bearing strata (when added all together) ranges from 1200 feet to over 3200" across the Delaware Basin.
There are recommendations for different lawyers on this site so retain one and treat this as a paying hobby. Good Luck.