BLM contends that safety depends primarily upon the well-bore's casing integrity through water-bearing formations.
Impermeable rock layers help to protect water above from deep fracking below both, the water and protective rock.
BLM's idealized model ignores 1) uncoated steel casing corrosion in Elpedro soil, 2) verticle faults & fractures through various substrata that help recharge aquifers but leak oil & gas, 3) increased risks of earthquakes with injection into wells, and 4) casing damage, therefrom.
Plugging of non-productive wells horizontally proves difficult after explosive casing perforation and fracking.