The Fracing Process

After a gas well is drilled, cased and cemented, it will be stimulated or "fraced" before the gas well will be put into production. The fracing process involves pumping fluid into a formation under sufficient pressure to create fractures in the rock thus allowing gas to flow through the fractures more freely to the gas well. By creating these new pathways, fracing can exponentially increase the amount of gas flow to the gas well. The fluid utilized in the fracing process consists largely of water and sand about 98% with the other 2% consisting of other additives used to improve the effectiveness of the frac. The sand is used to prop open the fractures once the pumping has stopped. The amount of water needed in the fracing process for a horizontal Marcellus Shale gas well can vary from about 2 million to 4 million gallons of freshwater.

After the formation is fractured and the pumping pressure has been relieved, the remaining portion of the fluid, mixed with any natural formation water present, begins to flow back through the well casing to the surface. This produced water may also contain dissolved constituents from the formation itself and is known as "flowback."

While the risk for groundwater pollution from actually fracturing the targeted formation itself is relatively low, pollution to the groundwater can easily occur form surface infiltration as a result of problems encountered during the process of returning the flowback to the surface and/or the improper handling of the flowback once it is has been returned to the surface. Proper surface handling methods can significantly reduce the likelihood of groundwater pollution or other environmental harm from the flowback. Once the flowback is returned to the surface, it is usually stored in tanks or lined pits/ponds to isolate it from the soils and groundwater. Because leaks and/or spills resulting from compromised tanks and/or pits can have a severe negative impact on the environment, proper design and maintenance of such tanks and pits is absolutely critical in the prevention of potential pollution to the groundwater resulting from the fracing process.

If you have more questions about the fracing process and how to protect the groundwater on your property contact an Environmental Attorney at the Quinn Law Firm.

REFERENCES

1. Harper, J. A. The Marcellus Shale. An Old "New" Gas Reservoir in Pennsylvania. Pennsylvania Geology Vo. 38, No.1

2. United States Department of Energy, The Office of Fossil Energy. Modern Shale Gas Development in the United States: A Primer. April 2009.

3. United States Department of Energy, The Office of Fossil Energy. State Oil and Natural Gas Regulations Designed to Protect Water Resources. May 2009.

4. The Pittsburgh Geological Society. Natural Gas Migration Problems in Western Pennsylvania.