Any DLE doubt is getting eradicated by Standard Lithium, page-18

You just cherry picked that info from two different websites. There's a dozen articles showing that standard drilled to 10k feet (3km).

But I got this notion that the motion of your ocean means small craft advisory. You're forgetting another important factor, just as important as grade. Flow rate. Regarding the flow rates:

"the Smackover Formation in the higher-grade South resource area averaging about1,715 m3/day per well"

And this is from Prairie's ann "Using flow parameters obtained from the pump test, consulting group Fluid Domains predicted a sustainable pumping rate of 2,700 m3/day over a three-year period".