Stimulating Reservoirs to Increase Natural Gas Production
A hot topic today, hydraulic fracturing technology has actually been used by the oilfield for about 60 years and is applied in 85 to 90% of the natural gas wells currently drilled in the United States. Some estimate that as much as 60% of the natural gas and 30% of the oil produced in the United States each day would be stranded without hydraulic fracturing – and an astounding 80% of all wells drilled in the next decade will require it.
It’s easy to see why hydraulic fracturing is important not only in the nation’s economic growth, but also in producing a cleaner fuel that reduces our carbon footprint compared to other fossil fuels such as bituminous coal.
Hydraulic fracturing stimulates the reservoir to free up energy
All reservoirs are different and contain varying kinds of rock. Some are easily stimulated to give up their oil and gas deposits. Many are difficult to reach – often lying more than a mile underground – and even more difficult to produce.
Hydraulic fracturing is simply a method of stimulating the reservoir to enhance oil and gas production. To stimulate the reservoir to recover more natural gas at an effective producing rate, water and proppant, typically sand, are pumped into the solid rock at high rates, fracturing the hydrocarbon-bearing rock. The propping agent keeps the cracks open so the hydrocarbon can flow out of the reservoir and into the wellbore.
Most hydraulic fracturing occurs a mile or more below the water table
Underground aquifers usually lie somewhere between 50 feet and 600 feet below the surface of the earth. Hydraulic fracturing takes place usually more than a mile (5,280 feet) below these aquifers, frequently at depths that exceed 10,000 feet.
In order for the water table to be affected by the operation, the diluted fluid would have to move upward the distance of the well, through horizontal – not vertical – strata. Pressures from the massive weight of the overlying rock beds generally preclude growth of hydraulic fractures more than a couple hundred feet upward. [Additionally, the upward migration ability of oil and gas is typically one tenth that of its ability to move vertically.]
Federal, state, and local regulations (and industry standard practices) for well construction have been in place for decades to protect drinking water aquifers from communication with hydrocarbon production. These measures dictate that surface casings be set and cemented a safe distance below the base of the water table, as defined by governmental agencies such as the US Geological Society. In the more than 50,000 wells fractured per year, there’s not a single documented case of fracturing into a drinking water aquifer.
Fracturing fluid consists of water, proppants and products we use every day
Water and proppant, which is used to keep the fissures open, make up 99.5% of the materials used to fracture a reservoir. The rest consists of ingredients we use every day at home or at work – things used in foods, food additives and preservatives, cosmetics and other pharmaceuticals, dishwashing liquid, laundry detergents, household cleaners, table salt, antiperspirant, and water purification.
Hydraulic fracturing plays a key role in your community
For areas that have been without energy production and have had to rely on other regions for oil and gas, hydraulic fracturing offers new opportunities to produce much-needed energy locally. Exploring this resource not only gives these communities new energy supplies, it also can generate royalties, tax revenues, and new well-paying job opportunities close to home.
And because fewer wells need to be drilled when hydraulic fracturing is employed, the impact to the earth’s surface is limited. In fact, the volume of energy previously produced by 10 wellbores can now be captured with a single wellbore that is properly cemented, cased, and stimulated.
Hydraulic fracturing older wells can rejuvenate them, producing more gas without having to drill new wells at the same locations. Over the last 50 years, more than a million of these wells in the United States alone have used this process—not one case of groundwater contamination has been documented.