All About Hydraulic Fracturing
Posted on: Tuesday, July 12, 2011
Fracking, fracing or frac'ing, are all shorthand terms for hydraulic fracturing. Hydraulic fracturing is a procedure that creates small fissures in the layers of rock that contains natural gas and oil. The fracking process consists of pumping water, sand and other additives under high pressure into natural gas and oil bearing rock formations more than a mile and a half below the surface. The fracking process allows natural gas or oil to flow into the wellbore.
Fracking is conducted after a well has been drilled and the drilling rig has been removed from the location. This process is used to increase natural gas or oil flow from a well and has been utilized by the industry for more than 60 years. It has allowed oil and gas companies to produce from layers of rock that once were considered impermeable.
The fluid used for fracking is approximately 99.5% water and sand, with a small amount of special-purpose additives. The sand is used to "prop" open the newly created fractures which allows the natural gas or oil to flow into the wellbore and up to the surface. You can think about it like this:
- a well completion technique
- a process of pumping sand, water and additives under high pressure into an underground formation
Fracking is not:
- part of the drilling process
- horizontal drilling
Can hydraulic fracturing pollute ground water? Because thousands of feet of impermeable rock separate natural gas and oil production zones and most drinking water aquifers, the probability of the frac water migrating into the water table is extremely low. The fact is that if a crack somehow formed to link a water table and a natural gas well, water would flow into the well and "kill" the well. It would be abundantly clear that a problem exists.
According to the Railroad Commission of Texas, there has never been a recorded case of frac fluid entering a water table. Groundwater is protected from natural gas and oil wells by seven layers of steel casing and cement.
Can natural gas migrate to a water table for any reason at all? Natural gas migration can occur naturally. In any area where natural gas deposits exist, it is possible for the gas to find its way into the water naturally. Migration could be a problem in areas where natural gas deposits are shallow such as in areas where natural gas deposits are shallow and located closer to the water table, such as areas where there are coal deposits.
The bottom line is that hydraulic fracturing is a game changer, allowing the extraction of at least six times as much recoverable natural gas today as there was a decade ago. The implications for energy security are startling as the technique is starting to be used to unlock "tight oil" which can dramatically increase the domestic reserves of crude oil. The risks associated with hydraulic fracturing are low and the potential rewards are high.