ReFINE Report Relies on Old, Previously Debunked Data
This week, ReFINE, a research consortium at Durham University (U.K.), published a new report focusing on the integrity of oil and gas wells, which alleges that “well leakage is an issue for shale exploitation.” As is customary with reports identifying risks of shale development, the media has taken the report to suggest a catastrophe waiting to happen, even going so far as to claim it’s a “blow” to those who say hydraulic fracturing is safe.
In order to arrive at its conclusion, however, the research team had to rely on old and completely debunked research, while also ignoring more recent studies that have found very low well failure rates. Here are five important facts to know about ReFINE’s report.
Fact #1: Studies finding high failure rates are based on (very!) old data
The researchers compiled data from 25 datasets from around the world with highly diverse results. As the report puts it:
“The datasets vary considerably in terms of the number of wells examined, their age and their designs. Therefore the percentage of wells that have had some form of well barrier or integrity failure is highly variable (1.9% – 75%)” (p. 1).
People tend to look at the upper bound of a risk assessment, and if that number is high, then the implication is that there’s a high risk – in this case, a 75 percent chance of well failure.
But it’s important to point out that the study finding wellbore integrity issues in 75 percent of wells was based on a 2005 study – which itself was looking at well data that were nearly 100 years old – in a California oilfield that had flooded. If you’re looking to find reliable data on well integrity issues today, focusing on statistics from the Roaring Twenties probably won’t yield the most reliable data. Other reports finding high well failure rates include studies on wells drilled in the 1970s.
How these data are materially relevant in the context of modern shale development would be difficult to ascertain, but clearly the suggestion that these high failure rates are somehow indicative of shale wells is absurd.
So, what have recent studies concluded about well integrity?
Take, for instance, an investigation recently completed by the Associated Press in several U.S. states. Based on Pennsylvania Department of Environmental Protection data compiled by the AP, the well failure rate is about one third of one-percent (0.33 percent) of all the oil and natural gas wells drilled in Pennsylvania since 2005.
In 2011, the Ground Water Protection Council also completed a study on wells in Ohio and Texas – it examined more than 34,000 wells drilled and completed in the state of Ohio between 1983 and 2007, and more than 187,000 wells drilled and completed in Texas between 1993 and 2008. The data show a failure rate of 0.03 percent in Ohio, and only about 0.01 percent in Texas. And remember, that conclusion was from data compiled in 2011, before many of the new casing regulations across the country were implemented.
This more recent data was not included in ReFINE’s report, although the data they used for the Marcellus region showed a leakage rate of less than two percent – which is still too high, for reasons that we highlight below.
Fact #2: Barrier failure and well integrity failure are not the same thing
Importantly, one of the studies cited most by ReFINE is a report published by the Society of Petroleum Engineers (SPE), which found the risk of well failure to be extremely low. While ReFINE quotes this report at length, here’s one aspect of the SPE report that ReFINE leaves out:
“For US wells, while individual barrier failures (containment maintained and no pollution indicated) in a specific well group may range from very low to several percent (depending on geographical area, operator, era, well type and maintenance quality), actual 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.”
What the SPE report is explaining is important: a well contains several barriers that are designed to protect groundwater, while the inner casings are designed to protect against any potential abnormalities. If there is sustained casing pressure (SCP), the accumulation of pressure in a well, it can affect one of the barriers – but even if one of these barriers fails, it doesn’t mean that the well’s integrity has been compromised, and it certainly doesn’t mean the well will leak.
Although ReFINE acknowledges that barrier failure and well integrity failure are not the same thing, it still lumps barrier failure and integrity failure together in its data set, which they explain this way:
“For well barrier and integrity failure our approach has been to include all the reliable datasets that are available, rather than de-select any data. This inclusive approach has the draw-back that the data we present include wells of different age, of different designs and drilled into different geology” (p. 2).
Another drawback to this approach is that there is no way to tell how many cases are barrier failure cases versus well integrity cases in ReFINE’s report. Given that the report’s purpose was to evaluate actual risk, and given that a leak can only occur if there is full well integrity failure, that distinction is crucial.
It is notable, though, that Professor Richard Davies of Durham University told the Telegraph that well leakage is only a “small risk.”
Fact #3: ReFINE’s data on well failure rates in the Marcellus relies heavily on anti-fracking activist Anthony Ingraffea
“In this study, the search criteria used to categorise leakage incidents in Pennsylvania followed the approach described by Ingraffea (2012) and are based on code violations reported during site inspections. Code violations that would constitute a well failure are those likely to result in a significantly increased risk of contaminants reaching either the surface or potable water sources. They include: (a) failure to case and cement the well properly; (b) excessive casing seat pressure; (c) failure to case and cement sufficiently to prevent migrations into fresh groundwater; and (d) insufficient cement and steel casings between the wellbore and the near-surface aquifer to prevent seepage of fluids. Using the Pennsylvania state database, a well barrier or integrity failure rate of 6.3% is identified for the years 2005e2013. This includes failures noted in inspection reports that were not recorded as a violation, following the methodology of Ingraffea (2012). Without including these reports, the failure rate would be 5%. This is higher than the 3.4% well leakage figure reported by Vidic et al. (2013) for the period 2008e2013, and close to the well failure rate of 6.2% reported by Ingraffea (2012)” (p. 5).
Ingraffea is, without a doubt, the most commonly cited source for anti-fracking activists hoping to find high leakage rates from wells, mostly because he trumpets the exact talking points that anti-fracking groups want him to say. Ingraffea famously claimed that half of all shale wells leak using data he said he found in “industry documents” – and by “industry documents he means a decade old chart from the Minerals Management Service (MMS). As a quick refresher, that MMS chart was an assessment of deepwater oil and gas wells in the Gulf of Mexico, not onshore shale wells. Second, the data presented in the chart were not examples of leaks, but rather what’s called sustained casing pressure (SCP), which is the accumulation of pressure in a well: it’s not the same thing as a leaking well.
Unfortunately, ReFINE uses this same tactic, quoting that same MMS document extensively:
“Data from the US Minerals Management Service show that, of 15,500 producing, shut in and temporarily abandoned wells in the outer continental shelf of the Gulf of Mexico, 6692 (43%) have sustained casing pressure on at least one casing annulus (Brufatto et al., 2003). Of these incidents, 47.1% occurred in the production strings, 26.2% in the surface casing, 16.3% in the intermediate casing, and 10.4% in the conductor pipe” (p. 6).
Granted, this particular assessment was clear that it examined offshore and onshore wells – a distinction that Ingraffea rarely makes. But it’s critically important to note that SCP is not the same thing as a leaking well, much less one that has experienced a full integrity failure.
Further, as we mentioned above, data compiled by the AP reveal a well failure rate of only about one third of one-percent (0.33 percent) in the Marcellus since 2005 – and that number doesn’t require the manipulation of data related to offshore development or misinforming the public about what the accumulation of pressure inside a well indicates.
Fact #4: ReFINE relies heavily on thoroughly debunked Duke studies
One of the researchers on the ReFINE team, Rob Jackson, is from the same Duke University team which brought us the infamous (and indeed thoroughly debunked) reports in 2011 and 2013 suggesting that shale development was causing methane to seep into water wells in Pennsylvania. So it was no surprise to see those Duke studies quoted at length. From the report:
“As argued by Davies (2011) and Jackson et al. (2013), poor well integrity is a far more likely cause of elevated concentrations of thermogenic methane in shallow groundwater and water supplies than pathways induced solely by hydraulic fracturing” (p. 13).
It’s notable that there is yet another concession that hydraulic fracturing is not the risk here. But, as EID has pointed out many times: the Duke team argues that shale development was the cause of contaminated water based on the presence of thermogenic methane. Biogenic gas is typically pre-existing and originating from shallower formations, whereas thermogenic gas is from deeper in the Earth. Thus, the researchers effectively linked the presence of thermogenic methane in water wells to shale development.
The Duke team’s conclusions have been directly contradicted by several studies. The U.S. Geological Survey recently released a report finding plenty of thermogenic methane in water wells in Sullivan County, Pennsylvania (an area where the Duke team also took samples). Importantly, USGS’ samples were baseline samples that predate drilling activity.
Additionally, a more recent study by led by Fred Baldassare from Echelon Applied Geochemistry Consulting also analyzed groundwater in northeastern Pennsylvania and found large amounts of thremogenic gas, prior to any natural gas development. In fact, 88 percent of the 67 water wells tested had some presence of thermogenic gas, and none of those sampled showed the presence of Marcellus gas. As the study explains,
“When future isotope data show a stray gas in this area to be thermogenic, that finding cannot be the sole basis for alleging that the stray gas was caused by oil or gas-well drilling.”
Fact #5: ReFINE finds “no evidence” of hydraulic fracturing causing contamination
ReFINE explains in the report:
“There are several factors in shale fracking operations, including the relatively low volumes of fluid and the short pumping times that make the upward propagation of very tall fractures unlikely” (p. 13).
And, as lead author Professor Davies also said to the Telegraph,
“A few years ago people were saying fracking causes water contamination. We have robustly researched that… and we have not found any evidence that fracking is the problem,” he said. (emphasis added)
The bottom line
After this extensive investigation into studies from around the world in order to assess the risk of shale development for the United Kingdom, here’s the conclusion ReFINE comes to:
“Of 143 active UK wells that were producing at the end of 2000, one has evidence of a well integrity failure” (p. 1).
The high failure rates in ReFINE’s report are based on studies that go all the way back to the 1920s, and suggests that all data from any time period is relevant to modern shale development. The researchers also incorrectly lump individual well barrier failure and complete integrity failure together. In addition, ReFINE relies on studies that have been thoroughly debunked by a variety of sources. Meanwhile, recent analyses – ignored by ReFINE – have found well failure rates of less than one percent, and even the report’s lead author has admitted that the risk of well failure is a “small risk.”
As always, the better question to ask is not, “are there risks?” but rather, “can those risks be managed?” With respect to well integrity – and all issued associated with shale development – the answer is clearly “yes.” There’s always room for improvement, to be sure; but the bottom line is that, despite some alarmism that always manages to dominate the headlines, the risk of well failure is actually exceedingly low.