UPDATE (7/10/2014; 3:15pm ET): A geologist in the industry with more than 30 years of experience working in Pennsylvania (on which Prof. Ingraffea based his study) contacted EID and contributed more insights on this latest flawed report (he has requested anonymity).
In an email to EID, he addressed Ingraffea’s bizarre contention that the incidence of well integrity issues is greater for unconventional wells, particularly in Northeastern Pennsylvania, than for conventional wells. Ingraffea makes this conclusion, not based on new data, but solely from Notice of Violation (NOV) reports from the Pennsylvania Department of Environmental Protection (DEP).
This geologist explains that Ingraffea’s conclusions are not valid for several reasons, specifically:
- “The vast majority of conventional wells did not have a large cellar like we use to drill shale wells. Most of the DEP’s detections of gas presence in the annular space between well casings were based on observations of bubbling in water-filled cellars. On conventional wells, where there were no subsurface cellars, these observations were not possible.”
- “There was a period in 2010 and 2011 that the DEP North Central region was writing Notice of Violations (NOVs) for every well where a bubble was observed from an annular space. This practice was not employed in the Southwest region (which explains the much lower rate for non-Northeast counties). This resulted in a large number of NOVs over a relatively short timeframe that indicated defective casing or cement.”
He further explains: “There can be no question that the degree of planning, design and execution employed to set and cement well casings in unconventional wells is orders of magnitude higher than it was for typical conventional wells in the past.” It is for all these reasons that “a comparison of inspection reports from conventional wells and unconventional wells is inappropriate.”
As for Ingraffea’s contention that older wells have more leakage problems, the data actually show that “the age of the well has little or no bearing on whether annular spaces leak. In fact, leakage should diminish with well age, as source zones deplete. There is clearly no evidence from the PA data set review by Ingraffea to support that the risk of leakage increases with well age.” (emphasis added)
To evaluate the impact of air emissions, he uses calculations based on PA DEP data, which are explained below:
“This data set suggests average flow from all annuli, if vented, of about 330 scf/d per well. If I apply that average to the 4,321 shale wells producing at year-end 2013, that is 1.425 mmcf/d, or 520 mmcf for the year. Converting that to CO2-equivalents, that’s 0.21 million metric tons of CO2-eq. (using conversion of CH4 x 21 = CO2-eq). Looking at EPA’s 2012 national GHG inventory, CH4 emissions for the total US E&P sector were 55.5 million metric tons of CO2-eq. PA’s annular venting represented 0.21 million MT of this, or about 0.38% of US E&P total, even though PA’s shale production was nearly 13% of US total.”
Thus, the annular venting from Pennsylvania shale wells “is pretty insignificant in the context of GHG emissions.”
Finally, according to this particular geologist, the linkage of pressure build-up (i.e. SCP) to well integrity failure is simply not accurate (EID has covered this before, too):
“A very high pressure could indicate a deep source of gas and a possible well integrity problem; this is extremely rare. A fair percentage of shale wells have some very small flow of gas in one or more annular spaces. This is not an indication of well failure, but rather an indication of very tiny flow paths within the cement that permit very small volumes of gas to escape, usually from fairly shallow sources. Naturally occurring methane in shallow groundwater is widespread in PA, and its presence is sometimes misinterpreted as something caused by nearby gas well drilling. I believe the DEP will confirm that of the several dozen stray gas investigations they have conducted related to shale gas wells, they have not found evidence where gas from great depth (i.e., Marcellus gas) has been found in shallow fresh groundwater zones.” (emphasis added)
—Original post, July 1, 2014—
When it comes to shale and hydraulic fracturing, Cornell professor Anthony Ingraffea may have as much credibility these days as a Kardashian wedding vow, his previous work having been repeatedly discredited by peers and colleagues alike. But give the man credit for one thing: he’s damn persistent.
Earlier this week, Ingraffea was back at it again with a new report, this one making the head-scratching claim that shale wells in Pennsylvania leak at higher rates than conventional ones. We guess that would be troubling, if it were actually true. But spend a little time looking through the actual report, and what comes through is classic Ingraffea: deftly combining creative data collection methods with specious presentation of findings, bending the science and exaggerating the certainty and severity of his conclusions all with an eye on scoring a good headline.
Of course, Ingraffea isn’t exactly the most disinterested observer out there. In addition to playing a starring role in Gasland, he also heads up an outfit called Physicians Scientists & Engineers for Healthy Energy, an organization funded (and essentially created) by the anti-development Park Foundation whose sole mission is to attack shale development. Ingraffea’s research is also the foundation for the claims of activists like Yoko Ono, Josh Fox and Mark Ruffalo – Ingraffea feeds them the content (after sufficiently dumbing-it-down, of course), and these leading lights deliver it to the masses. For his trouble, they even let him hang out with them sometimes.
Against that backdrop, here are six key facts to know about Ingraffea’s latest report.
Fact #1: Has nothing to say about actual well leakage rates
Just as a bit of background, Ingraffea essentially manufactured his own suite of activist talking points several years back by claiming that “half of all shale wells leak” based on so-called “industry documents” in a now infamous paper appearing in the 2003 edition of Oilfield Review. Only, there were two major problems with his argument: 1) the Oilfield Review paper was looking at offshore wells in the Gulf of Mexico, not onshore shale wells, and 2) it was focused specifically on instances of sustained casing pressure (SCP) being detected in a wellbore, which is not the same thing as well failure or an actual leak. In other words, Ingraffea’s entire basis for claiming “half of all shale wells leak” was founded on data that refer neither to shale wells nor to actual leaks!
Sustained casing pressure is the buildup of pressure in a well. In some cases, that pressure can lead to cracks or leaks within one of the barriers. Now, if wells only had a single casing string installed, then yes, SCP would be a serious problem. But in Pennsylvania, producers are required to incorporate no fewer than four casing strings into their well design and construction. And in Northeast Pennsylvania, a typical shale well will have up to seven separate barriers so that, if one is ever compromised, there are six layers of cement and steel in place to block any potential pathways of exposure. For a well to actually leak, then, every one of those layers of cement and steel would have to crack and fail – and such instances are exceedingly rare.
On that point, a spokesman for the British Columbia Oil and Gas Commission, Hardy Friederich, recently explained to the Vancouver Sun that while 10 percent of wells in B.C. have been found to have pressure or experienced some kind of leakage between the barriers inside the well, “This gas does not migrate to soil or water — it is trapped within the surface casing protection layer. From there it has to be vented to ensure it is safely disposed.”
Petroleum engineer George E. King explained it well in an International Society of Petroleum Engineers presentation when he said, “[A]ctual well integrity failures are very rare. Well integrity failure is where all barriers fail and a leak is possible. True well integrity failure rates are two to three orders of magnitude lower than single barrier failure rates.”
The distinction between SCP and actual well integrity failure and leakage is crucial if you’re trying to assess actual risk. But just like Ingraffea’s previous research, his latest paper also conflates SCP with actual leakage, in an effort to convince folks that the mere existence of the former is evidence of the latter. For instance the report gives quite an inclusive definition of a “leaking well.” As it states,
“A leaking well, in this context, is one in which zonal isolation along the wellbore is compromised due to a structural integrity failure of one or more of the cement and/or casing barriers.” (p. 1).
Again even if one barrier fails it does not mean that the entire well has failed and is leaking into the soil or water. To his credit, even Ingraffea admits (albeit in the “Methods” section in the back of the paper) that:
“We note that not all violations will result in groundwater contamination events” (p. 6)
Fact #2: Uses scribbled-in-the-margin notes and unfounded assumptions to increase “hit rate” for well integrity issues
The Ingraffea report comes to this conclusion:
“Pennsylvania state inspection records show compromised cement and or casing integrity in 0.7 – 9.1% of the active oil and gas wells drilled since 2000, with a 1.6 – to 2.7 – fold higher risk in unconventional wells spudded since 2009 relative to conventional well types. Hazard modeling suggests that the cumulative loss of structural integrity in wells across the state may actually be slightly higher than this, and upward of 12% for unconventional wells drilled since January 2009” (p. 4).
First of all, this passage is inclusive of SCP or any kind of leakage between barriers within the well. Therefore, it tells us nothing about whether the well is actually leaking out into the environment, which is the important point.
Second, Ingraffea resorts to creative measures to inflate these percentages (which don’t tell us anything about actual leakages), at times interpreting scribbled-in-the margin notes on inspection reports to his own liking. For instance, his entire argument that leakage instances are higher than we think they are is based on “findings” like this:
- “[V]iolation codes are sometimes entered incorrectly as non-cementing/casing issues and later corrected in violation comments.” (p. 2)
- “[W]ells drillied during boom periods may be more susceptible to loss of zonal isolation because operators might cut corners in an attempt to increase the number of wells drilled over a short period of time.” (p. 2)
- “This suggests that the majority of these active, older wells are no longer being inspected.” (p. 4)
In other words, Ingraffea is going way beyond the data in Pennsylvania’s Notice of Violation (NOV) database and is apparently applying his own interpretations and assumptions to boost his “hit rate” for wells with casing or cement integrity issues.
Fact #3: Pennsylvania’s regulations have been praised by the Obama administration
Contrary to Ingraffea’s insinuation that Pennsylvania DEP is lax on regulations, in reality, the agency has some of the most rigorous requirements for testing the mechanical integrity of wells – and its work has received high praise from the Obama administration.
Here’s a passage from the State Review of Oil and Natural Gas Environmental Regulations (STRONGER) (which was formed by the U.S. Environmental Protection Agency (EPA) and the and the Interstate Oil and Gas Compact Commission (IOGCC)):
“DEP is commended for its hydraulic fracturing program. Standards for well casing and cementing require that the operator conduct those activities to control the well at all times, prevent migration of gas or other fluids into sources of fresh groundwater; and prevent pollution of fresh groundwater. In February of 2011, DEP amended its regulations regarding well design and construction requirements to provide enhanced casing and cementing standards for new well construction. The requirements include standards for casing and cementing to meet anticipated pressures and protect resources and the environment. These standards address internal pressure rating, pressure testing of casing, centralization, and certification of joint welders. The program requires that cement used in the surface casing meet certain compressive strength and free water specifications and isolate the wellbore from fresh groundwater; contain pressures from drilling, completion, and production; protect the casing from the geochemical effects of the subsurface; and prevent gas flow in the annulus.” (emphasis added, pp. 10-11)
Fact #4: Uses debunked Dimock story as a primary example of well integrity failure
The conclusion of the Ingraffea report states,
“The NE region of Pennsylvania, in particular, has experienced several widely publicized methane migration cases related to loss of structural integrity of wells, including Dimock, Susquehanna County.” (p. 5)
It’s amazing that activists are still bringing up Dimock, as the claim that hydraulic fracturing had anything to do with water contamination has been thoroughly debunked by academics, independent experts, and government alike.
Here are the facts: In 2011, in response to allegations of groundwater impacts in Dimock, Pa., DEP investigated whether oil and gas activity was responsible. DEP ultimately issued a consent decree with the operator to address concerns, and the agency determined in November 2011 that the operator had fulfilled its obligations under that order. EPA agreed in late 2011 that the well water posed no immediate health threats. Gasland director Josh Fox then sent a petition to then-EPA administrator Lisa Jackson asking EPA to launch an investigation. With no new data – only that petition – EPA reversed course and began an investigation. EPA eventually released four sets of sampling data, and ultimately concluded in July 2012 that its earlier assessment was indeed correct, and there were no threat that required further action. According to EPA Regional Administrator Shawn M. Garvin,
“The sampling and an evaluation of the particular circumstances at each home did not indicate levels of contaminants that would give EPA reason to take further action. Throughout EPA’s work in Dimock, the Agency has used the best available scientific data to provide clarity to Dimock residents and address their concerns about the safety of their drinking water.”
Fact #5: Continues to get the data wrong on methane emissions
Remember Ingraffea was the one who famously said that hydraulic fracturing was a “gangplank to more warming,” claiming that methane emissions from natural gas development were so high that they cancel out the climate benefits of natural gas. While his latest report spends considerably less time discussing air emissions, it does allude to his long-standing claims. From the report:
“Casing and cement impairment in oil and gas wells can lead to methane migration into the atmosphere…” (p. 1)
Reporters have again latched on to Ingraffea’s climate claims in light of his new report. But as EID has noted before, Ingraffea’s research on this topic has been pretty thoroughly discredited – most notably by Intergovernmental Panel on Climate Change, the world’s more prominent group of climate scientists. From the IPCC’s latest assessment:
“While some studies estimate that around 5% of the produced gas escapes in the supply chain, other analyses estimate emissions as low as 1% (Stephenson et al., 2011; Howarth et al.,2011; Cathles et al., 2012). Central emission estimates of recent analyses are 2%─3% (+/‐1%) of the gas produced, where the emissions from conventional and unconventional gas are comparable.” (p. 19; emphasis added)
The Howarth study that the IPCC mentions (and then discredits) was done in conjunction with Ingraffea. That’s not all – the IPCC continues, explaining, “[t]aking into account revised estimates for fugitive emissions, recent lifecycle assessment indicate that specific GHG emission are reduced by one half” as more power plants are powered by natural gas. In other words, IPCC basically destroys Ingraffea’s claim that methane emissions cancel out the environmental benefits of natural gas.
Further, numerous studies have found Ingraffea’s claims to be without merit. The University of Texas/Environmental Defense Fund completed a study, which found methane leakage rates around 1.5 percent, which is far below the threshold for natural gas to maintain clear environmental benefits. EPA’s latest Greenhouse Gas Inventory found that methane emissions have declined significantly, falling 16.9 percent since 1990, with field production emissions falling more than 40 percent since 2006. From 2011 to 2012 (the most recent year for which data were available), methane emissions from natural gas systems declined by 12 percent.
That’s not all: reports by the U.S. Department of Energy, MIT, the University of Maryland have either disputed Ingraffea’s claims or released studies showing low methane leakage rates. Yet, Ingraffea persists.
Fact #6: Actual well failure rates are exceedingly low
So if activists like Ingraffea are conflating SCP with actual leakage – and providing misleading numbers to boot – what are the actual leakage rates on their own?
The Associated Press recently completed an investigation of water contamination and well integrity in four of the most prolific oil and gas states. It found no confirmed cases of water contamination in Texas; in Ohio there were only six cases; in West Virginia there were four. Finally, based on Pa. DEP data, the AP found a well failure rate of only about one-third of one percent (0.33 percent) of all the oil and natural gas wells drilled in Pennsylvania since 2005.
That research follows a 2011 study by the Ground Water Protection Council which looked at more than 34,000 wells in Ohio from 1983 to 2007 and more than 187,000 wells in Texas between 1993 and 2008. The GWPC found a well failure rate of 0.03 percent in Ohio and only about 0.01 percent in Texas. That was well before many of the new casing regulations across the U.S. and Canada were implemented – Texas, for example, adopted tough new standards last year.
Most recently, researchers at Cape Brenton University in Nova Scotia recently released two reports finding that the risk for water contamination and well integrity failure from hydraulic fracturing is quite low. As one study puts it, “[t]here is a low likelihood of casing integrity loss.”
The bottom line
In sum: Ingraffea, once again, inflates well leakage by conflating it with SCP, in an effort to make folks believe that leakage rates are far more serious than they actually are. In reality, rates of wells actually leaking into the outside environment are a mere fraction of one percent of all wells drilled across the United States.
Of course, an actual well failure rate of anything above zero means there’s room for improvement, and it is appropriate to continue researching risks and exploring ways to reduce them. However, with the percentage of actual failures being as low as it is, it’s clear the risks can and are being managed effectively, notwithstanding what our friend Tony Ingraffea might want you to believe.