Hydraulic Fracturing 101: What Every Representative, Environmentalist, Regulator, Reporter, Investor, University Researcher, Neighbor, and Engineer Should Know About Hydraulic Fracturing Risk

Abstract

Management - This is an excerpt from SPE 152596. The use of horizontal wells and hydraulic fracturing is so effective that it has been called “disruptive.” That is, it threatens the profitability and continued development of other energy sources, such as wind and solar, because it is much less expensive and far more reliable. Not only that, but compared with coal, natural gas produces only half the carbon dioxide and almost no sulfur, nitrous oxides, or mercury. Those demonstrable benefits over both traditional and alternative energy draw monetary and political attacks. Some university and media reports have focused on two main environmental concerns about using hydraulic fracturing to recover shale gas: Groundwater and/or surface-water contamination by methane or chemicals Escape of methane gas to the atmosphere These risks come from well construction, transportation of chemicals and fluids to the well site, and operation of the wells and the gas-transport system. This paper is an abbreviated analysis of a larger document on factual information about the purported risks of hydraulic fracturing: 1. Deep-well hydraulic fracturing does not travel through the rock far enough to harm fresh-water supplies. Thousands of field-monitoring tests and millions of fracturing jobs have confirmed this point. 2. In the deep, properly constructed wells that produce most US shale gas, the chance of even minor water contamination from fracturing chemicals is less than one event in a million fracture treatments, based on statistical analysis. When compared with the frequency of pollution from chemical dumps, acid mine drainage, general manufacturing, oil refining, and other energy- or product-producing activities, natural gas from conventional and unconventional sources generates more energy with the least impact and fewest problems. 3. Even as underground fractures grow (mostly outward with limited upward and downward growth), the total fracture extent remains thousands of feet below the deepest fresh water sands. The height of any fracture is limited by rock stresses, leakage of fracturing fluids within the target fracturing zone, and the hundreds of natural rock barriers that border the shale zone. Typical fracture height is 100 to 300 ft and separation between the top of the fracture and the deepest fresh water sands ranges from 3000 to over 5000 ft. 4. Water contamination due to spilled industrial chemicals occurs rarely and even less so for fracturing chemicals and comes exclusively from careless road transport, on-site storage and surface mixing, or well construction. These failings can be addressed successfully with existing technology and effective regulations. It is interesting to note that the states with the fewest problems are those with strong state regulations. Appropriate regulations already exist in most producing states and work very effectively to protect the environment.