Hydraulic fracturing, horizontal drilling, or "fracking," as it is commonly called, pumps large volumes of water, sand, and chemicals into a gas well to fracture or crack the shale and other tight rock formations, releasing gas into the wells. The process typically involves drilling approximately three kilometers below the earth's surface, and then one to three kilometers horizontally.
Hydraulic drilling has been used since the 1940s but its use has increased significantly during the last ten years due to the addition of directional and horizontal drilling techniques, which allows the oil and gas industry to access previously out-of-reach shale reserves.
The production of shale gas by way of hydraulic fracturing and horizontal drilling (fracking)has already had a major impact on both energy and ecology in the United States. From its birthplace in the Barnett Shale in East Texas in 2002, fracking has spread to 17 states, with more than 80,000 wells drilled or permitted since 2005. Moreover, the oil and gas industry is aggressively seeking to expand fracking to new states—including New York, California, and North Carolina.
In the last few years fracking has also gone global. The discovery of large volumes of new and potentially exploitable shale gas deposits has led to exploration and drilling in a growing number of countries. The U.S. remains the clear leader in shale gas development and use but shale gas production is already underway in Canada.