multi-stage fracing [MSF] "And the geology of the rock now being...

multi-stage fracing [MSF]

"And the geology of the rock now being drilled has changed. It used to be high porosity and permeability. Not anymore.”
Porosity is the volume of spaces within rock that might contain oil and gas. Permeability is how easily the oil or gas can flow through the rock.
For permeability, think of it this way - when a wave washes over beach sand the water flows through the sand this is - highly permeable. Most of the “easy” oil and gas has come from rocks like that; it’s the low hanging fruit. And in North America anyway, almost all of that is gone.Now think of a solid granite countertop. That is not so permeable. That rock is “tight”, hence the name “tight gas”. The big exciting shale gas plays that have huge reserves and produce big boomer wells come from this type of tight rock.
The permeability of the shale gas host rock is 1/1000ths or less of what the type of reservoirs that were drilled only a decade ago. There are a few new reservoirs being found in the world with porosities of 30%. But all the new shale gas is in the order of 1%. The key to getting that oil and gas out is knowing how to frac it. Fracing is an art as much as a science. Now if you if you drop a granite countertop, it shatters into 1000 pieces. If you could put every piece back together, you could still see the cracks around each piece. Those cracks are where the oil & gas would flow.
This is what fracing is doing the shale. It is exploiting natural cracks that exist in the rocks by reopening them and allowing flow.