In order for a rock unit at depth to be an excellent aquifer, what are the necessary and sufficient conditions

Question

a.) about 5% pore space
b.) soluble minerals in the rock
c.) inter-connected pore spaces
d.) clay minerals to prevent ground water from leaking out of the rock

Answer 1

In order to have a real good aquifer, you need ALL of them!

If this is a homework question (I suspect it is!), and you have to select only one as the best answer, then you need c, as that is the difference between porosity and permeability. Without c, you can hold water, but it won't move, so the "aquifer" will very quickly dry up.

But to be a good aquifer you definitely need c, a will give you sufficient water volume, b will give you better a and c but it will make the water "hard", and d will give the water confining boundaries so that it can be transported and used.

Answer 2

You should really be doing your homework on your own! Lets go through the options.....

a) If you have lots of pore spaces, but fluid cannot travel between those pore spaces, if you sink a bore hole in a given point, will you be able to draw much water out? Probably not.
b) Galena (PbS) is a pretty soluble mineral. You want lead in your drinking water? Thought not.
c) have another read through a)
d) hmm, probably not.

Answer 3

Is this from a homework question? really now. I'm not postive, but I'm going to go with c. To be an aquifer the rock unit must be porous(such as a sandstone), and usually will be bounded by shales (non porous) so the water/oil/gas is trapped in the porous rock unit. hope this helps.

Answer 4

If this a question and those are your choices... You need pore space in the rock and they must be interconnected or you could never tap the resource. C is more "right" than any of them.

Answer 5

The only one that is required is C. If the pores are not connected, nothing flows.