Explain HS2 "gas fracking" to me like I'm a 5-year old.
October 10, 2017 5:53 AM   Subscribe

A Canadian energy company is on the verge of receiving a permit to begin "gas fracking" about 1.3 miles from my house in rural Michigan. Their permit application explains that they will be using "gas" and I've since come to learn that the gas is HS2. [ I do not know what HS2 is, and google is failing me on this. ]

The well in question was once a regular pump oil-well, but has been out of use for many years. It's in an area of "sour gas" wells. [ I don't know what those are either. One of my brothers told me that they use the sour gas to add the stink to natural gas. I have no idea. ]

The permit also explains that they plan to inject the gas 3,800 ft underground. My water well is about 160 ft underground.

I'm obviously very concerned. There's a public hearing this week that I'm planning on attending. I feel pretty uniformed though, and would like to have a better understanding of the whole process and where the risks are.

Thank you.
posted by bricksNmortar to Home & Garden (16 answers total) 1 user marked this as a favorite
Hydrogen Sulfide is H2S, could HS2 be a bad transcription?

Its apparently a byproduct of fracking . Not used for fracking. It could be caused by microbes in the wells or chemical reactions

"Sour Gas Wells", have high concentrations of Hydrogen Sulphide
posted by TheAdamist at 6:01 AM on October 10 [1 favorite]

Doh! You're right.. it's H2S..
posted by bricksNmortar at 6:04 AM on October 10

Sour gas is natural gas with a lot of H2S and CO2 in it, generally with the emphasis on the former.

They will be injecting some kind of gas (presumably CO2) underground to break up the substrate that the natural gas is stuck in, to allow it to flow out easier.
posted by Jobst at 6:08 AM on October 10 [1 favorite]

(on preview, as TheAdamist says) Your google fu is probably failing because I think you mean H2S (hydrogen sulphide) rather than HS2 (the main reference for which is the High Speed 2 rail link in the UK).

In any event, I don't think they will be fracking using H2S, which tends to be a gas that is released by oil & gas extraction rather than something which is actively used in the process. In the case you mention, "sour gas" actually means a source of gas that has a high concentration of H2S.

H2S is a concern because it is highly toxic, although this is more usually a concern for workers at the wellsite that generally in the environment. My impression is that H2S is not generally considered the main cause for concern in fracking cases; the concern generally stems from exposure to fluids that are pumped down the borehole.

Fracking itself is the process of pumping fluid at high pressure into the ground with the goal of fracturing (hence "fracking") the rocks to make it easier for the oil & gas to be extracted. As in the case you mention, fracking generally happens at great depth and so, in theory, should have little effect on water sources near the surface. Most leakages are generally thought to occur from the borehole, rather than from the fracking itself, so any risk would likely depend on your proximity to the borehole and, potentially, the direction of flow of the groundwater (since this could transport contaminants further afield).

Since you are concerned about the effect on your water source, I would recommend contacting a local geologist, since they will probably be more familiar with the geology in your local area and can give you a better idea whether your concerns are warranted.

With regard to the public hearing, two of your main questions should be: what will be done to minimize leakage from the borehole, and what studies been performed to see how the local geology might influence any leakages (i.e. would the local geology naturally contain any leaks or would they exacerbate it)? Obviously, if you are unfamiliar with the jargon, this is where it would pay to have a friendly geologist on your side.
posted by oclipa at 6:35 AM on October 10 [1 favorite]

Fluids, not gases, have normally been used in the hydraulic fracturing process (hence the, uh, hydraulic part).

AFAIK, use of CO2 to replace the use of water is relatively new on the scene, but I'm not a fracker so take that with a grain of frac sand.
posted by mandolin conspiracy at 6:37 AM on October 10 [1 favorite]

H2S naturally contains the odor that can be described as "rotten eggs" - natural gas, after processing, has mercaptan added to it so that it can be detected by humans as a safety measure.

H2S is denser than air so the primary danger is that a "plume" of the gas can be released and travel via wind to areas where people are. In Canada, the danger zone for a plume of gas is calculated based on the pressure of the well and the percentage of H2S gas in the area. This danger zone is called the "Emergency Planning Zone" (or EPZ) and can be a handful of yards or a couple of miles. In order for it to be very large the pressure has to be very high, but if the original well had a pumpjack on it then it means that the product had to be pumped out rather than come out on its own, and if they're fracking then it means they have to work hard to release the gas from the earth's formation, so the pressure there is likely quite low to non-existent.

They wouldn't be using H2S gas to frack - it's usually a mix of water, sand, and chemical fluids. Two things might be happening here - either they're fracking to get the hard-to-get natural gas out, or they're using the old well as an "acid gas" injection well to dispose of gas that they don't want but also for obvious reasons don't want to release to the atmosphere. Disposal wells are quite common.

At the public hearing you'll want to find out what the company's Emergency Response Plan is and how they would let the public know immediately if there was a release. I haven't had much experience with US regulations but Canada's are very, very stringent and require a lot of planning, mapping, and training exercises to keep the public and the company's workers safe.

Source: I work in safety and emergency management for a variety of industries including oil and gas in Alberta.
posted by mireille at 6:39 AM on October 10 [2 favorites]

I would encourage you to speak to a proper scientist instead of reading opinions by a bunch of non technical people on a highly technicial subject. This thread alone shows a shocking amount of misinformation and lack of scientific knowledge. Dunning Kruger indeed. I work in this industry and have day to day experience in this matter.

First of all, fracking is carried out on rock formations where oil or gas cannot flow on their own. It sounds like since there was an old oil well already, fracking in your area is carried out to get the last drop of oil out of the ground, so to speak.

CO2 or H2S cannot be used in fracking, not on their own anyway. These are gases and compressible, a fact that one learns on high school science. Generally water and a bunch of other chemicals are used. (BTW water is a chemical and solvent, so the word chemical is not necessarily bad. Some are toxic, some are not)

Sour gas is NOT a by product of fracking. Sour gas comes from the oil or gas itself. It means that the oil and gas has high concentrations of sulphur, due to how it was formed. This can be dangerous when extracted from the ground, but any oil company will have stringent risk policies regarding H2S, if only to protect their workers. It is not clear from your description that the particular well that is being drilled has H2S as a risk.

Also, just to note, your water well is 160ft and the gas reservoir appears to be 3800ft Underground. There is over 2000 ft of rock between the water level and the gas, and direct contamination is pretty much impossible. However, there may be indirect contamination due to the company not taking sufficient care regarding disposal of their waste products from fracking. This would be the main risk — how are companies managing their waste.
posted by moiraine at 6:53 AM on October 10 [4 favorites]

I found a link to the EPA site and the Public Hearing Announcement for this Thursday's meeting.

EPA Public Hearing on Draft Underground Injection Permit.

It's still not clear to me what is actually going to be injected in the ground.

And, here's a link to the EPAs assessment of their initial request.


The EPA is essentially saying that their "Review of the permit application indicates that no significant environmental impact should result from the proposed injection. "

And that they intend to issue the permit. :(
posted by bricksNmortar at 7:16 AM on October 10

H2S naturally contains the odor that can be described as "rotten eggs"

Interesting tidbit I picked up when I had reason to work with it for a reaction I was running in the lab - as long as you can smell it, you're ok. Right around the time it gets up to dangerous amounts, it also overpowers your sense of smell so that you don't smell it at all anymore.
posted by solotoro at 7:23 AM on October 10

It's still not clear to me what is actually going to be injected in the ground.

That's completely intentional, because some are proprietary chemicals, and thus, treated as trade secrets. Here's a bit more on frac fluids from Frac Tracker Alliance, on the "concerned public" side of things. If you look to fracking companies for information, you'll find more optimistic spins on what they're pumping into the ground, like Haliburton's CleanStim® Hydraulic Fracturing Fluid System, "made with ingredients sourced from the food industry." ("Even though all the ingredients are acquired from food suppliers, the CleanStim fluid system should not be considered edible.")

In most states, companies don't have to disclose what they're pumping into the ground, thanks to Vice President and former Halliburton CEO Dick Cheney’s reported involvement in crafting what is known as the “Halliburton loophole.” But it seems you're lucky, in that Michigan requires operators to disclose the chemical additives through the nationwide FracFocus Chemical Disclosure Registry and conduct baseline sampling of nearby water wells, but I'm not sure if companies have to disclose chemicals in advance, or only post what they're doing after the fact.
posted by filthy light thief at 7:52 AM on October 10 [2 favorites]

Actually, looking at the second document OP linked to, there is no mention of fracking (hydraulic fracturing). In fact, it explicitly states that the proposed injection pressure "does not initiate fractures in the injection zone". It does not look like any fracking is planned.

In addition, there is no mention of H2S as a concern.

It appears this is a proposal to pump a gas down the well with the goal of increasing pressure to force out more oil ("blow down one straw to force a liquid up another straw"). I couldn't spot exactly what gas they are using, however this is usually either CO2, natural gas or nitrogren.

So, based on the documents linked, my impression is that the downhole pressure has dropped and the company simply wants pump gas down the hole to try to bring the downhole pressure back up and thus allow more oil to be extracted. To my layman's eyes, I don't see any particular reason for concern about your water supply; there doesn't appear to be any greater risk than at any other time since the well was initially drilled.

Obviously, you should ensure you get this from the horse's mouth at the public hearing.
posted by oclipa at 8:07 AM on October 10 [3 favorites]

I get the whole "hydraulic fracking = liquid .. "

But, it's bizarre to me that the EPA's annouement of this hearing indicates that they're going to inject gas. Even my neighbor, whose house is adjacent the field where the well is, thinks they're going to be injecting H2S.

Second paragraph, EPA Public Hearing on Draft Underground Injection Permit.

"Energex Petroleum, Inc. may inject gas for enhanced oil recovery..."
posted by bricksNmortar at 8:09 AM on October 10

I think oclipa has it in his second answer based on your updated information. This reads as a well workover/stimulation and as oclipa notes not of the fracking operation type. I'm not familiar with this side of the operations but see the Petroleum Industry Uses section of this Gas Lift page, which refers to using gas rather than fluids.
posted by mireille at 8:25 AM on October 10 [2 favorites]

As that incident shows, H2S is indeed a very dangerous material to work with and I would be very surprised if H2S was being injected into the well near you without it being mentioned in the application.

After a bit more reading around, apparently H2S can occasionally be injected into a well, but more for storage rather than stimulation. I would note however, that the Denver incident was an experimental well from over 40 years ago, so you would hope that things had improved quite a bit since then.

In any event, the following are some (admittedly somewhat dated) Oil & Gas Regulations for Michigan and these go into great detail about the restrictions on wells with exposure to H2S, which implies that this is given special consideration (and hence why I would be surprised if this wasn't mentioned in the application). For reference, this document indicates that a Class 1 H2S well (the one with the most risk) is described as having a risk of a dangerous concentration of gas of not less than 300ft.

In any event, obviously the best way to be sure is to ask at the public hearing (a) is H2S being injected into the well (rather than simply being produced by the well) and (b) what the H2S risk is related to the well (they may possibly refer to the Class of the well, with I(1) having the highest risk; anything with a risk other than Class I implies that there is minimal risk if you are more than 300ft from the well).

(if you do ask at the hearing, please update the answer here, as it would be interesting to know if they are indeed using H2S)
posted by oclipa at 1:35 AM on October 12

Follow up from the Public Hearing:

The permit to the EPA is a request to convert a "Producing Well" into an "Injection well."

The well in question is part of a complex of 5 or so wells which reach into an oil bearing area about 4,000 feet underground.

H2S is what they plan to inject into the well. They're calling it a gas injection, but the EPA geologist explained that at the pressures they plan to inject it, it will be a fluid. The H2S is a byproduct of the other producing wells in the area. It's currently being stored nearby and will be transported to the new injection well via existing underground pipes.

There is a tremendous amount of local opposition to the permit.
posted by bricksNmortar at 7:16 AM on October 16

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