Tag Archives: Cumnock Formation

Sanford/Lee County talk of fracking impacts

I noticed this little piece in the Sanford Herald a couple weeks ago in which MEC Chair/Lee County Commissioner Jim Womack spoke to a Chamber of Commerce luncheon focused on public policy. I want to tease out a few parts of this, and include some letters to the editor int he same newspaper discussing what was said at that event and related concerns about fracking development in the region (and let me say kudos to those who took the time to write and submit those comments).

By November or December, seismic testing trucks known as “thumpers” will be seen around Lee County, Womack said. Preliminary drilling for core samples could begin by next spring or summer…

I borrow from what my good friend at Golder Associates told me about thumpers, enhanced by the description Seamus McGraw included in his book, these are devices that shoot a pulse into the ground and measures the sound waves of its echo(s). The different strata of rock will reflect the sound waves differently, allowing geologists to better delineate how deep and thick those strata are. These should not too invasive as firms may regularly use these to find groundwater. The preliminary drilling should enhance knowledge of the strata as well, not only on depth, thickness, and orientation of the rock formations, but also allow analysis on the porosity and chemistry of those formations. Remember I talked about the estimate on the amount of natural gas ‘trapped’ in the Cumnock Formation by the geologist at Clemson University, which he did via a “back of the envelope” calculation based on the dimension of the formation? Getting the details on porosity and chemistry will refine that estimate, and though those test wells themselves may be a minor nuisance, it is a valuable step to help clarify how much gas we really have, and how feasible it will be to extract it. Perhaps a good analogy is getting a biopsy. I don’t know if it is reassuring or not about the timing of the exploratory wells: DENR Assistant Secretary Mitch Gillespie predicted back in March that such wells would be drilled in late 2013.

Keely Wood, a Lee County horse farm owner and fracking opponent, said five Texas towns have been left without water in the wake of natural gas drilling. She asked how Lee or Chatham counties would fare any different, and Womack responded that the N.C. Department of Environment and Natural Resources did a study and found that in just half a day, enough gallons flow through the Deep River to provide for all the water local drilling operations would ever need.

Based on the formula that DENR used to calculate water supply, which I am paraphrasing from the 2012 Shale Gas Report, I believe the Deep River does have sufficient flow to supply water to fracking operations. The calculation is something like 20% flow during the lowest recorded 7-day period of flow. As we should remember too well, the drought of 2007 was beyond severe, and we have good record of that flow. If flow in the Deep River during that drought met these minimum standards, than there is sufficient water supply to support this industrial use. The supply of raw water for fracking does not concern me the way that storage, treatment, and disposal of “return” or “produced” water does – and clearly, others are concerned enough to voice it.

I am glad Keely Wood submitted a full letter to the editor after this luncheon to express items not fully addressed there – the comments, though relatively few, show how polarized our society has become, particularly how individuals gloss over nuance and go straight to categorizing individuals at end points of the spectrum. This is a void of leadership – and I must say, in my observation of Jim Womack during MEC and study group meetings, I say he has been very level-handed. But somebody needs to step in between to say that supporting an initiative should not be done by knocking down those with an opposing perspective.

A similar letter begs the question of how widespread the “riches” of fracking will be, and I couldn’t but think on that a bit more this morning. His insights deserve an explanation of how the fees and taxation of fracking will benefit Lee County as a whole. I thought on the back-of-the-envelope calculations (cited above) ranging from potentially $200 million to $5 billion: when comparing that estimate against the DENR projection of 378 wells in the Triassic Basin, that ranges from $530,000 to $13.2 million per well. Remember that the development of a well is approximately $3 million. Of course, each well would have different results, some bringing up much more than average resources, while others bring much less.

“I think you’ll see our median family income go up 50 percent,” he said. “I think you’ll see that instead of the highest unemployment rate in central Carolina, we’ll have the lowest.”

Given what we know of the situation in Lee County: the inequal holdings of mineral rights, the number of property owners bound to unfavorable lease agreements, the relatively short duration for drilling development (all 378 wells in 8 years), and the lesser period of time for high labor demands (not to mention the question of qualified local workforce for this industry), the community deserves a thorough explanation on how development of natural gas extraction will boost median family income and how unemployment will fall.


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Of geological interest: the Cumnock Formation

I alluded to the geology of the Cumnock Formation in the Sanford sub-basin of the Triassic Basins as being a limiting factor in the ability of gas developers to extract resources safely. I must also acknowledge that the same formation is of significant geological interest in the debate as to whether hydraulic fracturing will be permitted in North Carolina. In their fact sheet on shale gas potential here, the NCGS noted that:

The Cumnock Formation includes a ~800 foot thick interval of Upper Triassic (Carnian) organic-rich black shale.

For comparison, the Marcellus Shale, which extends much further through the Appalachian Basin, ranges in thickness in Pennsylvania of approximately 790 feet in the east to approximately 50 feet in the west. So, the thickness of the Cumnock Formation makes it an attractive possible play. Thomas Murphy of the Penn State Marcellus Center for Outreach and Research reported at the Duke forum in early January that some well developers in Pennsylvania are working on fracturing the Marcellus Shale and the Utica Shale at a lower horizon from the same drill pad. Accessing multiple depths from the same drill pads seems to make mineral extraction more economical. I, for one, would be weary about the well integrity in wells used to access many horizons given that well casing has been shown to break down.

Another difference between the Cumnock and most other gas-rich shale formations is the fact that most of the Cumnock was actually formed in a terrestrial environment, as opposed to a marine environment. It is unclear how much difference that forming environment has in the content of the gas, and the content of other minerals.


Summary of ‘To Frac, or not to Frac’ at UNC-CH, 1/31/2012

Tuesday afternoon, a hydrogeologist from Clemson, Larry Murdoch, came to the UNC Chapel Hill campus to speak about hydraulic fracturing. The talk was organized by the UNC Institute for the Environment. The presentation was from the perspective that no one in the audience is an expert, and therefore was a good, thorough overview of the subject. He explained the process of hydraulic fracturing, the access to resources the technique provides that we had not had before, and the risks associated with the practice, particularly due to the volume of the materials.The Reese Felts Digital Newsroom at the UNC School of Journalism & Mass Communication published a summary of the talk:

Summary of ‘To frac, or not to frac’ talk at UNC

Of great interest to me, is the estimate of the value of the natural gas contained in the Cumnock Formation – the main gas-rich formation within the Sanford sub-basin of the Triassic Basins. Murdoch calculated the value of natural gas in the formation based on known variables: the extent of the formation, the thickness of the formation, the geochemistry (data is from Reid and Milici, 2008), and the price of gas. The thickness, chemistry, and price each have a range of values, and using the ranges, and the average figure in those ranges, he had some useful numbers to consider in the discussion for North Carolina:

…this formation could hold between $0.2 billion and $5 billion of natural gas.

The calculation based on the averages for the total value of natural gas is $2.5 billion. After the presentation, I overheard an official at DENR report that their preliminary findings on the amount of gas in the shale are quite similar to the calculation Murdoch made, and added that this is a drop in the bucket compared to other gas-rich shale in the country. Note that these figures are the estimated value of the gas and do not include the costs associated with extraction.