Replies to This Discussion

Permalink Reply by sesport on June 11, 2009 at 17:36

just edited - bump

Permalink Reply by sesport on June 12, 2009 at 5:22

Here's an everyday joe kind of question for ???, not sure who ... geologists?

In regards to the formation(s) above the HS, how permeable and/or porous are they? How likely (maybe percentage-wise) would it be for frac fluids to migrate over time up into water sources?

Also, as other formations may or may not be developed using frac fluids, how would the same questions be answered when asked re. those formations?

Thanks in advance - :0)

Permalink Reply by jffree1 on June 12, 2009 at 6:14

Hey Sesport,
That was my main question and I have given it some thought. Here's what I know...

Water is heavy. It always moves from a higher level to a lower one. In other words, it always flows in the direction of least resistence.
Gases, on the other hand, move from a place of high pressure to one where the pressure is lower. That is why fracturing works so well. It creates openings in the rock which are lower pressure and the gas flows to the openings.

So the migration of frac chemicals (in any direction) would depend (in part) on how many water molecules the chemical is bonded to or whether that same chemical may be in suspension in the water. Since they are additives to the frac coctail, I would surmise that they are forming either suspensions (what you get when you add wettable powders to water) or solutions (what you get when you add other liquids to water). If they are in suspense (solids), eventually they will settle out and migration would cease. If they are in solution (liquids), they would migrate with the water not recovered from the well, in whatever direction that water takes.

Either way, physics says that these chemicals would not migrate upward unless they are in a gaseous state. So then it becomes a question of temperature and whether any of these additives would be changed from a solid or liquid state to a gaseous state by the temperatures in the formation.

Permalink Reply by sesport on June 12, 2009 at 6:28

Thanks, jffree. And I understand it is rather hot down there. So, the suspension is like when we were kids and made rock candy with sugar water? The water evaporates and we had the treat to eat (much later if I recall, had to learn patience, lol) And the solutions are like say coffee or tea? ( I think I've been wathcing too much Bill Nye & Beakman's World :0)

Permalink Reply by jffree1 on June 12, 2009 at 6:52

That's right, sesport. And, although temp. (state) and pressure (direction) will have some effect on where and how the fluids move (water will move upward under pressure... think artesion well flowing to the surface) I think that most of the chemicals are going to be recoved in the frac fluids flowing back from the well. Whatever is left is a very small amount and not likely to migrate upward to water tables.

I think it is more likely to find water contamination from bad casing/concrete in the borehole going through the water table. That would apply to all wells and not just frac'ed wells.

Permalink Reply by jffree1 on June 12, 2009 at 6:59

Actually, coffee and tea are infusions. A solution would be like putting Mr. Clean in a bucket of mop water.

Permalink Reply by Grillin' - MmmMmm on June 12, 2009 at 6:34

Due to the depths involved, any water bearing sand in the vicinity of the HS would have saline water, not fresh water. The drinking water reservoirs are considerably shallower than the HS. For the frac fluids to migrate up through numerous strata, some permeable, some highly impereable, would be highly unlikely.

And remember, we don't sit there pumping frac fluids for weeks and months. Its a "one time event" and then the well is turned around and produced.

Permalink Reply by sesport on June 12, 2009 at 6:47

Thanks Mmmarkkk. Yes, saline is dense ... I'm thinking the Great Salt Lake ...

I think it's understood that the frac process is short in duration (but there is also re-fracing, isn't there?). I think what we're trying to determine is whether frac chemicals can be heated to the gaseous state "down under" and whether those gases could then migrate to shallower depths?

Or, does this stuff get trapped in pocket say like the salt domes?

How highly unlikely are you saying, 75%, 90% ?

Permalink Reply by sesport on June 12, 2009 at 7:30

Sorry, previously posted in the wrong place.

I think the issue currently at hand is repealing the exemption that applies to the frac process only. Doesn't the disposal process have its own set of codes? Or is there some exemption(s) re. disposal that are also being considered for repeal?

Permalink Reply by sesport on June 12, 2009 at 10:09

Thank you, Braveheart. I have a link to the repeal/legislation posted at the top of the page. Will also check yours out.

:0)

Permalink Reply by jffree1 on June 12, 2009 at 7:27

If you guys want more reading material, go look at the report I posted yesterday in BLOGS "MODERN SHALE GAS DEVELOPEMENT IN THE U.S.: A PRIMER" from the DOE. It cites a couple hundred sources for environmental ACTS, EPA regs, industry reports and various studies.

Permalink Reply by sesport on June 12, 2009 at 14:19

Okay, to be clear, this is the text of the legislation.

A BILL

To repeal the exemption for hydraulic fracturing in the Safe Drinking Water Act, and for other purposes.

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled,

SECTION 1. REGULATION OF HYDRAULIC FRACTURING.

Section 1421(d)(1) of the Safe Drinking Water Act (42 U.S.C. 300h(d)(1)) is amended by striking subparagraph (B) and inserting:
‘(B) includes the underground injection of fluids or propping agents pursuant to hydraulic fracturing operations related to oil, gas, or geothermal production activities; but

‘(C) excludes the underground injection of natural gas for purposes of storage.’.

We are only talking about the frac process and fluids used in this process.

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