Ann: Resource Estimates for Three Sub-salt Exploration Wells, page-61

Yeah the presence of helium isn't really the risk here, it's getting wells to flow economic rates in fractured basement.

The use of laterals is a big help here as it massively increases the chance of intersecting fractures but they still need enough natural fractures to get a connected fracture network. There is basically zero matrix permeability in basement so it's all hanging on the fractures. You need at least two dominant, orthogonal joint sets (like occurs at Palm Valley) to create an interconnected network, and those joints need to be open. Fractured basement plays usually don't meet these criteria but when they do they are often massive producers. If memory serves there was an oil discovery off Vietnam that produces from fractured granite basement and it was a barnstormer.