Qjmalecki

Fracking section - second paragraph

Greetings Qjmalecki. Because you seem to be taking the lead in editing this section, I will bring these observations to your attention. The second paragraph is actually better than most in this section, as it contains only one inaccuracy, a couple of incomplete descriptions, a minor redundancy, and one statement that, though true, belongs in another section:

“In hydraulic fracturing, well operators force hundreds of thousands to millions of gallons of water mixed with a variety of chemicals through the wellbore casing into the rock. Sand is added to the water as a proppant to keep the fractures in the rock open, thus enabling the gas to flow into the casing and then to the surface. The chemicals are added to the frack fluid to reduce friction and combat corrosion. After the "frack," the gas is extracted and nearly 30 percent to 70 percent of the mixture of water, chemicals, and frack fluid flow back to the surface. Additionally, a significant amount of brine, containing salts and other minerals, may be produced with the gas.”

The opening sentence states that the volume used in fracking ranges from hundreds of thousands to millions of gallons of But Is “hundreds of thousands” really the lower end of fracking volumes? Whoever put this in was oblivious to the logical contradiction that, in the following paragraph, is a note that the average small-volume frac uses 80,000 gallons of water. If true, then “hundreds of thousands” cannot possibly be the lower volume limit. What is the actual lower end of the volume range? The best source on the point is a 2015 US Geological Survey report on frac volumes (Tanya J. Gallegos and Brian A. Varela, Trends in Hydraulic Fracturing …, US Geological Survey, Scientific Investigation Report 2014-5131) shows (Table 2 on page 11) that in the most recent period suited (2000-2010), some fracs injected as little as 2 cubic meters (about 500 gallons) of water. So to be correct, the phrase “hundreds of thousands” should be replaced with “hundreds”.

Sand is not the only proppant used. “Sand” should instead be “Sand or other particles”.

There are many reasons for adding chemical besides these two. No need to list them all, but the sentence should be changed to: “Chemicals are added to the fluid to perform such functions as reducing friction and inhibiting corrosion.”

According to the text, in addition to water and chemicals, there is “frack fluid” mixed in. What, the confused reader may ask, is this “frack fluid”, if not the water and chemicals already mentioned?

The final sentence is true, but the brine ([[produced water]) is commonly produced from both hydraulically fracked wells and non-hydraulically fracked wells. To imply that this is a characteristic only of hydraulic fracturing is highly misleading. This sentence should be put in another section.

Thanks. Plazak (talk) 03:19, 2 September 2015 (UTC)

Hello Plazak, The ranges of the volume of water use per frack are inconsistent, and the Gallegos & Varela report helps correct them.

I agree with you on the points about what the proppants are, and what the chemicals do.

The "mixture of water, chemicals, and frack fluid" should be changed to the "mixture of water, sand, and chemicals."

How is the final sentence misleading? Mentioning that brine may be produced from hydraulically fractured wells doesn't imply an exclusive relationship between brine production and fracked wells. Brine production often follows hydraulic fracturing. The brine production may appear in both the hydraulically fracked well and non-hydraulically fracked well articles. But rather than saying "may be produced with the gas," it would more accurately say ". . .containing salts and other minerals which occur naturally underground, may be brought to the surface of the well in the fracking process."

Your thoughts? Thank you. Qjmalecki (talk) 18:20, 2 September 2015 (UTC)Qjmalecki

"In the fracking process"? Not really. The water comes up after the fracking process. But it also comes up in many wells which are not fracked at all. The ratio of gas to water is mostly a function of the formation, not the completion method. If fracked wells succeed in producing more gas, they will also produce more water, but in more or less the same proportion.

How about: "Many gas-bearing formations also contain water, which will flow up the wellbore to the surface along with the gas, in both hydraulically fractured and non-hydraulically fractured wells. This produced water often has a high content of salt and other dissolved minerals that occur in the formation." Regards. Plazak (talk) 03:30, 3 September 2015 (UTC)

Paragraph 3 - Part 1

Paragraph 3, part one Thank you for your patience in bearing with me. Your willingness to get things right is appreciated.

“Determining which fracking technique is appropriate for well productivity depends largely on the type of source rock from which to extract oil or gas. If the source rock is characterized by low-permeability — which refers to the rock's ability to let substances, i.e. gas, pass through it — and low-porosity — which refers to the amount of passageways the rock contains — then the source rock may be considered an unconventional source of gas.[83] Fracking for shale gas, which is one of the three main unconventional gas sources, involves drilling a borehole vertically until it reaches a lateral shale rock formation, at which point the drill turns to follow the rock for hundreds or thousands of feet horizontally.[86”

1) Rock “type” is shale, limestone, etc. Different shales are the same rock type, but may need different frac techniques. I would substitute “properties”.

2) The first misstatement is the assertion that unconventional reservoirs must have low porosity. In fact, shales, including gas shales, do not generally have low porosity. The cited source (a Total website) notes that what it calls “tight gas” reservoirs tend to have low porosity, but makes no such statement about gas shales.

3) The second inaccuracy is the description of porosity as the “amount of passageways.” Porosity refers to the proportion of the formation not composed of solid particles; the porosity may or may not form “passageways”. Better to just forget about porosity and emphasize permeability, which is the important thing.

4) What is referred to as “source rock” three times in the text is more properly “reservoir rock.” “Source rock” is the layer in which the hydrocarbon is generated from kerogen; “reservoir rock” is the layer where it accumulates, and from which it is extracted by the well. In the case of shale gas, source rock and reservoir rock are one and the same, but in tight gas deposits and in conventional reservoirs, they are usually different. This source rock/reservoir rock confusion also occurs elsewhere in this section.

5) The final phrase of the first sentence implies that to be an “unconventional source of gas,” a formation must have low porosity and low permeability. As stated above, gas shales often do not have low porosity, and coalbed methane, which is not mentioned here, but is certainly an unconventional source of gas, often has high permeability. This overbroad statement should be narrowed by changing “unconventional source of gas” to “source of tight gas or shale gas.”

Second sentence: “Fracking for shale gas … involves drilling …” Please remember that fracking is a completion technique, not a drilling technique; drilling is not part of the fracking process. Also, horizontal shale wells are not universal. Since 2000, horizontal wells have become standard practice in the US and Canada, but vertical shale wells are still being drilled in North America, and the article should not overgeneralize (although a lot of websites do overgeneralize). About 10% of Eagle Ford wells in 2014 were vertical (how many of these are gas I don’t know).(Grant Nulle, US Tight Oil Trends, US Energy Information Administration, slide 31, 2015). I recently downloaded databases of Marcellus wells permitted in 2014 in Pennsylvania and West Virginia, and in each state, a bit over 1 percent of the wells were verticals. Outside of North America, vertical shale wells are apparently still common, both in China,[1] and Argentina. [2],[3] I know that this probably seems like a minor point. I would propose something like:

“Although hydraulically fractured shale gas wells first became commercial in vertical boreholes, drilling and fracking horizontal shale wells has become standard practice in the US and Canada. Horizontal wells are first drilled vertically until the borehole approaches the target formation, after which the drill turns and drills horizontally, remaining in the targeted shale for hundreds or thousands of feet.

The third sentence in this paragraph should probably just be eliminated. But enough for now. Regards. Plazak (talk) 01:41, 5 September 2015 (UTC)

I appreciate your helpful comments. I've made minor adjustments, but have other work to take care of that may keep me from more editing over the next day or two. Qjmalecki (talk) 02:41, 7 September 2015 (UTC)Qjmalecki

Third sentence

“In contrast, conventional oil and gas sources have more often been found closer to ground-surface-level and are characterized by higher rock permeability and porosity; the porosity and permeability of conventional source rocks naturally enable the flow of oil or gas with less intensive hydraulic fracturing techniques, and — due to the relatively shorter distance to drill from ground-surface-level and typically no associated horizontal drilling — permit a lower well capacity with less water and chemicals required to fill the well and fracture the source rock.”

The statement that the average depth of hydraulically fractured shale gas wells being drilled today is deeper, and that on average they are more highly pressured than conventional wells is probably true. However, thousands of shale gas wells are shallow, just as some conventional reservoirs are deep, and some are shallow. The Antrim Shale in Michigan, and the New Albany Shale of the Illinois Basin, both produce gas from wells as shallow as 600 feet.(John B. Curtis, “Fractured shale gas systems,” AAPG Bulletin, Nov. 2002, v.86 n.11 p.1921-1938.)

My real objection is to the last part of the sentence, which seems to theorize that shallower boreholes, both conventional and nonconventional, require smaller fracs because of their lesser depth. The size of the frac depends on a number of things, but, as far as I know, depth is not one of them. I do not understand the phrase: “lower well capacity.” Does it mean smaller well casing volume, or perhaps lower capability to produce gas? The sentence cites two references, but neither one in any way supports the statement, but it is possible that I have misinterpreted the meaning.

Again, “porosity” is mistakenly thrown in where permeability alone is meant. Again “source rock” used when “reservoir rock” would be the correct term.

Regards. Plazak (talk) 00:57, 10 September 2015 (UTC)

Capacity refers to the extent of space. If the depth or distance of one well is greater than another, and their diameter measurements the same, the greater distance means a greater well capacity. If the frac requires the frac fluid to fill the well space completely, then a well with greater capacity will require a greater volume of frac fluid.

The use of the term "intensity" is a bit ambiguous. It may refer to the amount of fluid used to frac, and the energy used to inject it.

If the depth of a conventional source to frac were the same as the depth of an unconventional source to frac, there would nevertheless be the distance that is drilled horizontally for wells to produce shale gas from lateral formations. The distance horizontally which adds hundreds or thousands of feet to the vertical, amounts to greater well capacity, more frac fluid, and thus a greater intensity frac than fracking for a conventional source.

Qjmalecki (talk) 04:22, 7 October 2015 (UTC)qjmalecki

I'm sorry, but this is all your own WP:OR, and may sound plausible at first glance, but is completely wrong. You have obviously not even done the simple arithmetic of calculating the cased borehole volume. If you had, you would have seen how silly your theory is. For even if the cased wellbore volume were entirely filled with frac fluid, which it isn't, for reasons not worth going into right now, that volume is tiny compared to the millions of gallons of frac fluid used in massive hydraulic fracturing. Please calculate it, and see for yourself. This is an excellent illustration of why you should not be putting your Original Research into the Wikipedia article. Unless you can cite a Reliable Source for this theory of yours, it has to go. Regards. Plazak (talk) 13:52, 7 October 2015 (UTC)

Effect on health and the environment

Thank you for your recent edits to the Natural gas article. It is a pleasure communicating with an editor who deals in facts, and I will try to be equally as rational. Please excuse the length of this note, but there are a number of references here, and they deserve individual consideration.

The most problematic statement statement in this section is the following:

"The decades in development of drilling technology from conventional to unconventional oil & gas production has not only improved access to natural gas in low-permeability reservoir rocks, but also posed significant adverse impacts on environmental and public health.

“Posed” is an odd choice of verbs here, because it is more commonly used (as it is in the first reference) in the sense of “posed a risk” or “posed a threat”, referring to possible rather than a certain result. But here it seems to mean “caused”. If the adverse effects are demonstrable, I believe that “caused” would be a clearer word choice.

Taking environment and public health separately. An “adverse impact on public health” means what? Clearly, it means people sickened or injured; “significant” means a lot of people sickened or injured. So which of the cited sources documents all these sickened or injured? If any of them do, I missed it. You have diligently piled up a number of references for this statement, but I believe that none of them support the statement exactly as it is. None of them documented any adverse impacts on public health, let alone “significant adverse impacts.” One source documents adverse impacts on the environment, but the "significant" appears to be a POV judgement.

Referennce #1: The APHA does not say that fracking has caused adverse impacts on public health, only warning that it might. Rather than having me or you or some other editor put words in the mouth of the APHA, the most NPOV way to handle it is to let them speak for themselves, and put in the article something like the following:

In October 2012, the American Public Health Association adopted a policy on hydraulic fracturing that stated, in part: "HVHF poses potential risks to public health and the environment, including groundwater and surface water contamination, climate change, air pollution, and worker health."

Reference #2: The strong accusations made by the Center for Biological Diversity appear impressive – until you read the source document (WRCB, Letter to EPA), and realize how flimsy the accusations are, as has been pointed out elsewhere (Bakersfield Californian). For the benefit of those who didn’t understand the earlier report, the director of the State Water Resources Control Board put this unambiguous statement in his report: (Report dated 23 Sept 2014)

“Thus far, the test results indicate that the injection wells have not degraded groundwater quality in the tested water supply wells.”

So far we have detections of three contaminants commonly found in the Central Valley due to either agriculture or to natural causes (WRCB, Salinity)(USGS, Salinity), plus thallium. I am not familiar with thallium, but the EPA describes thallium contamination as usually due to the electronics industry (EPA - thallium). The State Water Resources Control Board sees no reason to blame the hits on the Class II disposal wells, and even states that the injection wells do not appear to have degraded water quality. Finally, nothing in the reports indicate that the disposal wells have any connection with hydraulic fracturing. There is, of course, a legitimate question as to why the state Division of Oil and Gas issued Class II permits for aquifers with less than 3,000 ppm TDS (the drinking water standard is 500 ppm), but that is a political question.

To sum up, this allegation should not be used in a Wikipedia article, first, because the CBD is not a reliable source, second, because the supposed source document for the allegation does not support what the CBD says it does, third, because the state agency that did the study has contradicted the allegation, and finally, because the injection wells involved have no known connection to hydraulic fracturing, as it is not known if they ever injected any water from hydraulically fractured wells.

Reference #3: I am unsure how the citation on the great increase of earthquakes in Oklahoma is supposed to support the statement. First, recent research has tied the increase in central Oklahoma (where the 5.6-magnitude quake occurred) to produced water from conventional, non-hydraulically fractured oil wells in the Hunton Group, so that is a bad example.(Dispelling myths about seismicity),(Myths and facts on wastewater injection),(Potential for induced seismicity in Oklahoma) A better example would be a few damaging earthquakes in Arkansas, which were connected to hydraulically fractured gas wells. But, as far as I know, there have been no injuries, and therefore no effect on public health. I don’t know how you would say that the earthquakes have had an adverse effect on the environment. If you like, you could correctly add a statement to the article that the induced seismicity has damaged property, but that is different from the current text, as it is neither human health, nor the environment.

Reference #4: The headline itself says it all: "May Have". The study is certainly of concern, but you cannot make a definite statement that "significant adverse impact" has occurred, based on just a "may have".

Reference #5: In contrast to the first four citations, the 5th citation documents actual adverse effect on the environment, in the form of dissolved methane in aquifers near gas wells. There have been a lot of studies back and forth on this, but the majority of studies conclude that the methane comes from leaking gas wells. The majority of studies also note that the methane is most likely due to poor well construction, not to hydraulic fracturing itself (NY Times, Well leaks). To be accurate, one could say that contamination was caused by hydraulically fractured wells, but one could not correctly say that the contamination was caused by hydraulic fracturing itself. But ignoring that point, does this constitute “significant” adverse impact? I don’t think so, but you disagree, and such disagreement is reasonable. Some national news organizations have emphasized lack of widespread contamination: (National Public Radio, EPA finds no widespread drinking water pollution from fracking). In the end, “significant” or “not significant” are POV judgements, and should not be left up the POV of editors. Instead, we should depend on outside reliable sources.

To address this question of environmental impact (at least on water, which is what the methane study addresses) we have the EPA’s Draft Assessment on the subject, and mindful of the fact that it is still in draft, we should just refer to it, and quote from its conclusions:

In 2010, the US Congress asked the US EPA to study the impact of hydraulic fracturing on drinking water. In June 2015, after a multiyear study, the EPA released its Draft Assessment on the Potential Impacts to Drinking Water Resources from Hydraulic Fracturing Activities. The draft was published for public comment and peer review. The EPA summarized in a press release, which said, in part:

“…while hydraulic fracturing activities in the U.S. are carried out in a way that have not led to widespread, systemic impacts on drinking water resources, there are potential vulnerabilities in the water lifecycle that could impact drinking water.”

“EPA’s review of data sources available to the agency found specific instances where well integrity and waste water management related to hydraulic fracturing activities impacted drinking water resources, but they were small compared to the large number of hydraulically fractured wells across the country.”(reference: US Environmental Protection Agency, (EPA Releases Draft Assessment on the Potential Impacts to Drinking Water Resources from Hydraulic Fracturing Activities, 4 June 2015.)

The EPA is not perfect, but given the POV extremes on this issue, I believe that the EPA is about as reliable a source as you are likely to find on this issue.

In summary, your citations document the following:

• A major US health organization believes that massive hydraulic fracturing poses risks to public health.
• Some property damage has occurred in Arkansas due to earthquakes caused by injection of produced water from hydraulically fractured wells (actually, your source did not mention this, but you could have found one that did).
• Gas wells have caused some methane contamination of groundwater, (but the EPA believes that the contamination is not widespread).

All of the above would be fair statements backed by reliable sources. But the overbroad assertion that massive hydraulic fracturing has caused "significant adverse impacts on environmental and public health" is perhaps your own strong opinion, but is not backed by the sources cited. What do you think? Regards. Plazak (talk) 22:56, 10 October 2015 (UTC)