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What Happens to Old Gas and Oil Wells? Adapted from Information by the American Geosciences Institute, The Railroad Commission of Texas, and the California Department of Conservation With one million active gas and oil wells in the United States, you may wonder what happens when a well reaches the end of its productive life, or fails to find economic quantities of gas or oil. Regulators require well operators to remove all equipment and plug the well to prevent leaks. Cement is typically pumped down the well to fill the top and bottom portions, as well as any other areas where gas and oil may leak. Plugging procedures are specific to each well and depend heavily on the local con- ditions and risks. These procedures are meant to prevent contamination of groundwater as well as leaks on the surface. Unfortunately, there are several cases where wells were not properly plugged before they were abandoned, leaving them orphaned. Orphaned wells usually happen when well operators go bankrupt before the wells can be plugged. The U.S. Environmental Protection Agency in the late 1980s, estimated roughly 200,000 of 1.2 million abandoned wells may not have been properly plugged. Wells drilled before the 1950s when plugging procedures were less rigor- ous, may also be leaking. State and federal regulators, as well as volunteer industry programs, have plugged tens of thousands of these wells. While efforts to plug all orphaned wells continues, the exact number is unknown. Since 1859, more than 3.7 million wells have been drilled across the coun- try, and their histories are not always well-documented. Unplugged or poorly plugged wells can affect: ; Groundwater - Old wells could have degraded well casing or cement which may allow gas, oil, or salty water to leak into aquifers. ; Methane emissions - An analysis of 138 abandoned wells in Wyoming, Colorado, Utah, and Ohio, found over 40% of unplugged wells leaked methane, compared to less than 1% of plugged wells. ; The surface environment - Orphaned sites may have old equipment, contaminated soil from small spills, and other waste at the surface. In some unplugged or poorly plugged wells, oil, gas, drilling mud, or salty water can rise up the well and spill at the ground surface. Over the past few decades, states have been increasing enforcement of plugging and cleanup requirements, with some requiring a performance bond or financial assurance from the operator that a well will be plugged and the well site restored. However, the bonds may not cover all of the expenses associated with plugging and cleanup expenses if an operator goes bankrupt; which is why some states collect fees or production surcharges from operators specifically for remediation of orphaned wells and associated surface equipment. Progress is being made. “ The Railroad Commission of Texas (the state’s regulatory agency for gas and oil) plugged nearly 35,000 orphaned wells, including offshore wells between 1984 and 2008. In fiscal year 2017 (9/1/2016 - 8/31/2017), the agency plugged an additional 918 orphaned wells; in 2018, more than 1360 abandoned wells were plugged; and during 2019, over 1700 of these wells were plugged. “ The Pennsylvania Well Plugging Program plugged more than 3000 orphaned wells between 1989 and 2017. “ The voluntary Oklahoma program has cleaned up and restored 15,000 abandoned well sites in Oklahoma since 1994. “ California has plugged roughly 1400 orphaned wells since 1977. According to the California Department of Conservation, there are still approximately 30,000 abandoned wells which need to be plugged.. “ The U.S. Bureau of Land Management reclaimed 295 orphaned well sites in ten states from 1988 to 2009. 55 WorldWide Drilling Resource ® NOVEMBER 2019 An abandoned gas and oil site in Oklahoma, before and after being remediated. Photo courtesy of the Oklahoma Energy Resources Board. ENV