Hydraulic Fracturing Defined
WIKI defines hydraulic fracturing or “frac jobs” (or “frac’ing” in the industry, or with the misspelling “fracking” being common in media reports) as a process that results in the creation of fractures in rocks. The fracturing is done from a wellbore drilled into reservoir rock formations to increase the rate and ultimate recovery of oil and natural gas.
Hydraulic fractures may be natural or man-made, and are extended by internal fluid pressure which opens the fracture and causes it to extend through the rock. Natural hydraulic fractures include volcanic dikes, sills, and fracturing by ice – as in frost weathering. Man-made fluid-driven fractures are formed at depth in a borehole and extend into targeted formations. The fracture width is typically maintained after the injection by introducing a proppant into the injected fluid. Proppant is a material, such as grains of sand, ceramic, or other particulates, that prevent the fractures from closing when the injection is stopped.
Environmental and Health/Safety Concerns
There is a fair amount of controversy that goes hand-in hand with the current manner in which fracing is being administered. Some of those concerns include not only environmental issues but basic safety and health concerns. These have emerged and are being debated at both the state and federal levels. Some of those concerned about current fracing techniques register the following concerns:
1. Ground water contamination
2. Lower air quality
3. Gas and hydraulic fracturing chemicals reaching the surface
4. The mishandling of waste related to fracing
Locations with “possible” related to local fracing operations in the area include:
Dimock, Pennsylvania where CNN reports gas migration from the fracing process into water aquifers near the city.
Clearfield County, PA where there was a well blew out that spewed natural gas and 35,000 gallons of drilling fluid across rural Pennsylvania causing hat is being described as “moderate” environmental impact.
Wyoming Water Well Testing resulted in the EPA issuing this statement: The affected well owners were advised not to drink the water at the recommendation of the U.S. Department of Health and Human Services’ Agency for Toxic Substances and Disease Registry, and told to use alternate sources of water for drinking and cooking, agency officials said. In all fairness, it is important to note that agency officials have said publicly that the EPA has not reached any conclusions about the sources of chemical compounds found in drinking water wells, including hydraulic fracturing, or “fracking,” the controversial process used to extract natural gas from underground.
Hydraulic Fracturing
There is a great website sponsored by Chesapeake Energy called HydraulicFracturing.com. It talks in depth about not only the process, but also the recipe for the fracturing fluids, the State (and other regulatory bodies depending on the location of the fracing operations) requirements for groundwater protection, the use of water in the fracing process, and specifically Chesapeake’s Green Frac™ program.
Hydraulic Fracturing – The Process
Simplified Steps In Hydraulic Fracturing
1. Water, sand and additives are pumped at extremely high pressures down the wellbore.
2. The liquid goes through perforated sections of the wellbore and into the surrounding formation, fracturing the rock and injecting sand or proppants into the cracks to hold them open.
3. Experts continually monitor and gauge pressures, fluids and proppants, studying how the sand reacts when it hits the bottom of the wellbore, slowly increasing the density of sand to water as the frac progresses.
4. This process may be repeated multiple times, in “stages” to reach maximum areas of the wellbore. When this is done, the wellbore is temporarily plugged between each stage to maintain the highest water pressure possible and get maximum fracturing results in the rock.
5. The frac plugs are drilled or removed from the wellbore and the well is tested for results.
6. The water pressure is reduced and fluids are returned up the wellbore for disposal or treatment and re-use, leaving the sand in place to prop open the cracks and allow the gas to flow.
By visiting this Hydraulic Fracturing – The Process site you can view some very clear and concise graphics related to the fracing process.
The Recipe for Fracturing Fluids
Fracturing fluids contain water, sand and other additives that allow fracturing to be performed in a safe and effective manner. Additives used in hydraulic fracturing fluids include a number of compounds found in common consumer products. Both a written and graphical breakdown of these additives can be found here: Fracturing Ingredients
Groundwater Protection
As stated previously, State oil and gas regulatory programs place great emphasis on protecting groundwater. Current well construction requirements consist of installing multiple layers of protective steel casing surrounded by cement. These elements are specifically designed and installed to protect freshwater aquifers. Companies carrying out fracing projects are required to work together with federal, state, and local agencies to ensure that water used for deep shale gas development is consistent with water use plans and does not cause problems with water “consumers” in or near the fracing project.
More information on Chesapeake specific Groundwater Protection efforts and lots of great facing fact sheets including info on Barnett Shale, Fayetteville Shale, Haynesville Shale, and Marcellus Shale please visit: Groundwater Protection
It is also important to note that the Ground Water Protection Council (GWPC) issued a report in April of 2009 called Modern Shale Gas Development In The United States: A Primer (this Primer is a GREAT research resource for beginners like myself in understanding the history and process of fracing) that basically states that the potential for fracing deep shale gas wells will impact groundwater is extremely remote, as low as one in 200 million.
Water Usage
Water is an essential component of deep shale gas development during both the drilling and hydraulic fracturing, or fracing, processes. Chesapeake and other companies use water for drilling, where a mixture of clay and water is used to carry rock cuttings to the surface, as well as to cool and lubricate the drillbits. Drilling a typical deep shale gas well requires between 65,000 and 600,000 gallons of water.
The Water Usage page of Chesepeake’s site goes into greater detail and makes comparisons that even a novice like myself can understand.
Conclusion
I am admittedly pro oil and gas industry. I will also admit that fracing is the only process that has raised my “common sense” radar in a very long time. Likely because this is a process I know the least about and have had very little interaction with, so I continue to research to try to understand the science behind hydraulic fracturing. Of course there are “anti-fracing” groups and websites popping up all over, but so far they seem only to be “very strong opinions” and not based on science. For this blogger, I will continue to keep an open mind, support the oil and gas community in their fracing efforts but continue to educate myself.
I just can’t seem to shake shake this weird, “this is going to come back and bite us in ten years” feeling.
Is anyone else having this feeling?