Cryogenic Fracking - a Superior and Environmentally Friendly Substitute for Hydraulic Fracturing?

Cryogenic Fracking - A Superior and Environmentally Friendly Substitute for Hydraulic Fracturing?

Almost without exception, today’s shale wells are stimulated using water-based fracturing fluids (slickwater). This technique is popular due to its ability to transport proppant effectively at a relatively inexpensive cost. However, it is a magnet for criticism from environmentalists, who are concerned about the incredible volume of water needed as well as the resulting contaminated wastewater which must be treated and disposed of properly. Water use is often cited as one of the primary reasons that there are more than 435 pending ballot measures seeking a moratorium on fracking in various parts of the US as well as an outright hydraulic fracturing ban in New York state. However, an answer may already be developed and derisked to a certain degree.

Researchers at the Colorado School of Mines have developed a method to unlock hydrocarbons trapped in shale without using any water at all. They are seeking to perfect Cryogenic fracturing, which replaces water with searing cold liquid nitrogen (or carbon dioxide). Used at temperatures below minus 321 Fahrenheit, it is pumped underground at high pressure. Once it comes into contact with the heated, pressurized shale, a reaction occurs which caused the shale to crack open and creates fissures through which the hydrocarbons can gush out. They liken it to pouring hot water onto a frozen car windshield, with the sharp and sudden temperature change causing the glass to crack.

There are several positive results from using this technique. First, the liquid nitrogen will evaporate underground eliminating the need for costly recovery and retreatment. Further, they claim it will form bigger fissures or canals through which hydrocarbons can be extracted, boosting oil and gas production. In theory, the below-freezing liquid should actually be more rather than less effective than water-based methods. Second, it may well solve problems with water-sensitive formations or those with an unwanted amount of clay.

Slickwater fracking often causes water saturation around the fracture and clay swelling, hindering the ability to transport hydrocarbons from the fracture to the well bore. Some shale absorbs water very quickly and the entire formation may swell in size and hinder transport through the fissures we have created. Even in a best-case scenario, using hydraulic fracturing results is a low recovery factor, caused largely by water trapping. Technology in fracking is moving incredibly fast, and methods successful in one play will be mimicked wherever the geology seems similar elsewhere.

Cryogenic fracturing has evolved from failed fracturing attempts with gaseous nitrogen first introduced during the ‘70’s and ‘80’s. Critics claim nitrogen does not have a high enough viscosity to carry proppant efficiently, and that the fluid itself may prove to be more costly than producers prefer. Further, it requires special piping and equipment which proves a challenge unto itself. Opinions vary as to whether the new technology is market ready or completely de-risked. Few technological advancements in this industry are. So much is learned by trial and effort, both success and failure. However, competitors are always paying attention and mimicking the success found by others and the techniques they employ. You best believe the industry had a close eye on what happens in Colorado, with Pioneer Natural Resources having first crack at the new technology.

It is generally agreed that cryogenic fracturing enhances porosity, permeability and rock-fluid contact area. Liquid nitrogen actually provides the highest temperature difference between reservoir formation and injecting fluid which enhances the fracking potential. It is inodorous, inert (non-reactive), and harmless to both humans and the environment. It has been used more extensively in coal-bed methane extraction which reflected some concern regarding transfer of proppants throughout the fissures. This could likely be offset by using ultra-light proppants and a higher injection fluid flow rate. Another advantage is that cryogenic fracking would allow exploration in area of water scarcity.

N2 also is environmentally very safe in that it readily evaporates after the treatment, causes no groundwater contamination, and involves no carcinogenic and corrosive compounds. Further, as rock properties and thermal gradient solely control the creation of fissures, subsurface tectonic forces have little to no influence on it. In addition to shale, cryogenic fracking is effective in exploring coal bed methane (CBM), and is also promising as a method conducive to the extraction of petrocarbons in tight sands and low permeability reservoirs. Finally, it is a likely source of remedy for those exploration efforts incurring large amounts of clay.

Could this be the answer to overcoming New York’s ban on hydraulic fracking? Regretfully, no. No matter what is proposed to be used in lieu of water, New York politicians will surely rise up to defeat it. Already, a bill has passed the State Assembly on March 12, to prevent Southern Tier Solutions from using the method. It specifically bans the use of liquified carbon dioxide, the fracking fluid proposed for use by the company. They actually proposed to use carbon captured from power plants as its source. Too bad, because Southern Tier had some ambitious plans to lease a million or more acres for the project.

How’d you like to be a dirt-poor farmer in Southern New York and look over your fence to see your Pennsylvania neighbor riding his new John Deere, pulling his new combine, and happily counting his blessing because of hydraulic fracking on or near his land? Seems hardly fair. Additionally, New York could definitely use the revenue. At time of publication, although the economy in general seems acceptable, New York carries more debt ($368 B) than any state except California. Household debt of New Yorkers totaled almost $870M, or almost 6% of total household debt in America (year ending 2021). According to Credit Karma, each New Yorker carries almost $70K in household debt. That’s 14th among major US cities, not alarming, but surely something each NY resident would like to lower. The truth is, even a small farm could easily raise that figure with just the initial bonus payment, not to mention subsequent royalty checks.

New Yorkers, don’t get your hopes up. The politicians there are ruthless, and determined to “save” NY from the evils of fracking. Already, just the mention by Southern Tier of cryogenic fracking has sent them into a tizzy. Almost immediately, legislation was put in place to prevent such. The bill passed the state assembly on March 12 of this year and has sense been voted on and passed. In fact, Senate Majority Leader Andrea Stewart-Cousins made it clear that “New York doesn’t have much of an appetite for fracking on any kind.” Her sentiments were echoed by Gov. Kathy Hochul’s office. Truth is, if you want to make a living using artificial stimulation (fracking) of any kind in New York you are going to be in for a big disappointment. Thank goodness most of our other states are more sensible.

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