Hydraulic Fracturing

Hydraulic fracturing is a process commonly used in the extraction of oil and natural gas from low-permeability reservoirs often found thousands of feet below the earth’s surface. Specially engineered fluids are pumped at high pressures and rates such that tiny cracks are created in the reservoir formation. These cracks allow oil and natural gas to flow more freely into the well bore, thereby enhancing the productivity of the target formation.

More than 98 percent of frac fluid is water. Proppant, most often sand, is another important part of the frac fluid, as the sand remains in the fractures created to keep them literally propped open. The remainder of the frac fluid typically includes low concentrations of three to 12 chemical additives. Chemicals serve many functions in hydraulic fracturing, from limiting the growth of bacteria to preventing corrosion of the well casing.

Hydraulic fracturing typically occurs deep underground, well below groundwater reservoirs. Such depth separation essentially mitigates the potential for drinking water contamination from the fracturing operation. As the well itself is being drilled, it is cased in steel and surrounded by layers of cement. This well-design standard not only helps ensure the integrity of the well for optimum production, it also provides multiple levels of protection between underground fresh water and the production zone of the oil or natural gas well. Water that is injected into the formation during hydraulic fracturing is collected and either recycled to be used in similar future jobs or disposed of according to stringent state regulations.

For more than 60 years, hydraulic fracturing has been safely performed on more than one million wells. Today, operators use hydraulic fracturing on as many as 35,000 oil and natural gas wells each year. The ability to produce more oil and natural gas from older wells and to develop new supplies once thought impossible has dramatically altered the U.S. energy landscape.

Recent activity in the Marcellus Shale in Pennsylvania and New York has brought increased attention to the hydraulic fracturing process. Some people have expressed concern that hydraulic fracturing poses a threat to drinking water from chemicals used in fracturing fluids.

Energen has routinely used hydraulic fracturing in our oil and natural gas exploration and production operations since the mid-1980s. At that time, we were pioneering the exploration and development of coalbed methane in Alabama’s Black Warrior Basin.

Although we currently have no operations in the major natural gas shale plays, Energen utilizes hydraulic fracturing extensively, including in the Permian Basin where the company is focused on the development of oil and natural gas liquids. There have been no known incidents of aquifer or surface groundwater contamination from any of Energen’s hydraulic fracturing operations.

We believe that Energen’s hydraulic fracturing operations have minimal impact on the environment and human health. In fact, hydraulic fracturing provides significant environmental benefits compared to conventional drilling, such as drilling fewer wells to access equivalent reserves, lower drilling waste volumes, a smaller environmental footprint, less land disturbance, and reduced air emissions.

All of Energen’s hydraulic fracturing processes are governed by the states in which it operates: Alabama, Colorado, Louisiana, New Mexico and Texas. These regulations are extensive and, depending on the location, also reflect federal, national forest, and Native American interests.

Energen is an inaugural participant of the FracFocus Chemical Disclosure Registry. Established by the Ground Water Protection Council and the Interstate Oil and Gas Compact Commission, this Web-based project features a public database of hydraulic fracturing fluid composition on a well-by-well basis.

For our hydraulic fracturing needs, Energen contracts with large, well-established service providers who have a history of evaluating their chemicals and making improvements to benefit the environment while preserving the integrity of the oil and gas completion process. We support these “green” efforts and look forward to assessing their potential application in future drilling operations.

Energen is a good steward of water usage in its operations. We use only the amount of water needed for a specific job. In an effort to reuse produced and flow-back water, Energen has a pilot program now under way in the Permian Basin to test the potential of recycling this water for repeat use in other frac operations. For salt water disposal, Energen uses commercial water disposal sites regulated by the U.S. Environmental Protection Agency.

In August 2011, the Shale Gas Subcommittee of the Secretary of Energy Advisory Board (advisory panel) issued its initial report on shale gas development and hydraulic fracturing. According to the advisory panel’s initial report: “Regulators and geophysical experts agree that the likelihood of properly injected fracturing fluid reaching drinking water through fractures is remote when there is a large depth separation between drinking water sources and the producing zone. In the great majority of regions where shale gas is being produced, such separation exists and there are few, if any, documented examples of such migration.”

The report further noted that if a water well becomes contaminated, it is more likely to be contaminated with methane gas rather than frac fluid and that this contamination is not necessarily the result of hydraulic fracturing. “The presence of methane in [water] wells surrounding a shale gas production site is not ipso facto evidence of methane leakage from the fractured producing well since methane may be present in surrounding shallow methane deposits or the result of past conventional drilling activity.”