8 Min Read
(John Kemp is a Reuters market analyst. The views expressed are his own)
By John Kemp
LONDON, Dec 12 (Reuters) - It is time to stop demonising hydraulic fracturing. Oil and gas production is a messy, dirty business that produces all sorts of harmful waste. But the chemicals used in hydraulic fracturing are no more dangerous than those frequently used in acidizing and other conventional well treatments.
Fracking poses no more risk to the environment than production from conventional wells, which the industry and regulators have learned to manage successfully in recent decades to minimise the impact on local communities.
Much of the political opposition to fracking seems to be driven by general hostility to fossil fuels, and a lack of understanding about how oil and gas are produced from conventional wells, rather than by any special dangers associated with hydraulic fracturing itself.
The risks commonly cited by opponents (contamination of drinking water, disposal of salty waste water and chemicals from fracked wells, and seismic activity) are just as much of a problem when drilling ordinary wells.
Differences between conventional and fracked wells are overstated. Fracking went mainstream long ago. It is part of a spectrum of techniques for improving flow rates and the ultimate amount of hydrocarbons recovered from a broad range of oil and gas-bearing formations.
The oil industry has been using explosives to fracture reservoir rocks and improve oil flow to the foot of wells since 1865.
From the middle of the 20th century, the dangerous practice of dynamiting wells was gradually replaced by hydraulic fracturing using high pressure fluid injection. The first frack job was performed in Kansas' Hugoton field as long ago as 1947.
By 2002, long before shale gas and oil had emerged on the political radar, hydraulic fracturing had been used a million times in the United States, according to a recent survey by the National Petroleum Council (NPC).
Up to 95 percent of wells are now fracked, accounting for 43 percent of total U.S. oil production and 67 percent of natural gas production, according to the NPC ("Prudent Development: Realising the Potential of North America's Abundant Natural Gas and Oil Resources," September 2011).
Fracking is routinely used to improve recovery from a wide range of oil and gas wells, not only those drilled into tight formations such as the Barnett shale in Texas and North Dakota's Bakken.
Critics claim fracking poses a heightened risk to freshwater water aquifers that provide vital supplies for households and farms.
In most cases, however, oil and gas-bearing formations occur thousands of feet below the drinking water aquifers and are separated from them by one or more impermeable layers of rock capping the reservoir. If they were not, the oil and gas, being lighter than water, would already have migrated up into the freshwater zone or even escaped at the surface.
Fracking risks damaging cap rock and allowing oil, gas or fracking fluids to flow up into the drinking water layer. But given the large distance separating the oil and gas layers from freshwater, and the large number of other stresses on oil and gas reservoirs, including formation damage from drilling, the risks are not significantly higher than for conventional wells.
Critics have expressed concern about chemical additives used in fracking. In many cases, fracking companies have tried to keep the cocktails commercially confidential, adding to the suspicion, though this is changing with voluntary and mandatory disclosure via registries such as FracFocus.
But the industry has long pumped all sorts of unpleasant chemicals down conventional wells. Hydrochloric and hydrofluoric acids are commonly used to enlarge the natural pores in the reservoir or fracture the formation. After an acid job, spent acid, dissolved rock and sediments are pumped out of the well during the backflush.
The drilling mud used in every well routinely contains diesel or synthetic oils, as well as chemical additives such as foaming agents, thinners, bactericides and emulsifiers to regulate various aspects of performance, which must be carefully removed from the well after use and disposed of safely.
A typical frack job uses 43,000 gallons of frack fluid and 68,000 pounds of sand, according to Professor Norman Hyne of the University of Tulsa. But a massive frack job could employ more than 1 million gallons of fluid and 3 million pounds of sand ("Petroleum Geology, Exploration, Drilling and Production", 2001).
Carefully disposing of huge volumes of waste water is therefore essential to avoid contaminating surface watercourses and subsurface aquifers. But again the waste disposal problem is not new.
In every oil and gas formation, hydrocarbons are mixed with large amounts of salty water, which is brought to the surface along with the oil and gas. Oilfield brine shares the pores in the reservoir rock with the oil and gas, and can have up to 20 times the salt content of sea water.
Conventional wells produce huge amounts of oilfield brine, which is typically re-injected into deep salt-water aquifers to ensure safe disposal (often as part of a programme to maintain pressure and production rates in the oil reservoir). Waste water produced by fracking poses exactly the same problems.
Hydraulic fracturing has been blamed for a swarm of small earth tremors in Oklahoma and near the town of Blackpool in northern England. But managing subsidence and other problems associated with oil and production (as well as sub-surface mining) is another well-established problem that is not special to fracking.
Even without fracking, extraction of oil and water from the giant Wilmington oil field in Long Beach, California, caused the surface of the town to subside 9 metres. Oil production left much of the city below sea-level, until a massive water-injection programme was undertaken to prevent further slippage, and dikes were be erected to protect it from inundation.
In the North Sea, the Ekofisk production platform had to be jacked up in the 1980s after the seabed subsided several metres, leaving its boat deck below the water line.
Fracking operations are often more visible and have a larger surface footprint in local communities than conventional oil and gas wells. Hundreds of trucks and tankers are needed to haul water and sand to the site and carry waste away afterwards.
Fracking has also opened up oil and gas formations in parts of North America and elsewhere that have not experienced large-scale drilling before, or at least not for many decades.
Nevertheless, drilling is not impossible even in highly urbanised areas.
One of the most prolific petroleum basins on the planet lies under the cities of Los Angeles, Long Beach and Beverly Hills in California. The Beverly Hills High School has 19 oil wells on campus pumping several hundred barrels of oil per day.
There will be occasional spills and accidents. No form of energy production is without some risk. The challenge is to contain it to an acceptable level and compensate the victims when things go wrong.
For the industry and regulators, the biggest challenge will be maintaining and improving standards during the largest drilling boom in 30 years. But that is a challenge caused by rapid growth, not the fracking technology itself. (Editing by Jason Neely)