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FYI
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The Railroad Commission reported that in 2002, there were 266,820 oil and 88,048
gas wells registered by the state, about 88,000 of which were not producing*. Commission
records indicate that between FY 1992 and FY 2002, operators of oil and gas wells voluntarly plugged some 90,000 wells, while some 24,449 abandoned wells remain
inactive and in violation of the commission's plugging rule*. Between FY 92 and
FY 2002, the Railroad Commission plugged 15,306 abandoned wells*. Still, an
estimated 1.58 million wells have been drilled in Texas over the past 80 years, and records indicated that only 550,000 have been plugged. Many of these unplugged
wells are potential vehicles for the migration of salt water and hazardous waste injected underground.*
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(Source: Information provided by letter from Richard Ginn, Oil and
Gas Division, Railroad Commission of Texas, January 30, 1998.).
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The TCEQ emphasizes prevention of leaks rather than after-the-fact
groundwater monitoring to ensure that no leaks have occurred in hazardous waste wells. In most cases, no groundwater monitoring is
required for hazardous waste injection wells. Instead, operators of industrial hazardous waste injection wells are required to perform an
annual mechanical integrity test of the well casing. A space between the tubing in which the waste is injected and a second casing is filled with a
pressurized anticorrosive fluid. Since the pressure of the fluid within the well is known, any drop in pressure would indicate a leak in either the tubing or casing.
The usefulness of monitoring wells to detect leakages is hotly debated.
There have been cases where groundwater monitoring wells have detected contamination above an injection zone that was not identified by
monitoring the pressure within the injection well itself. In addition, environmental groups are concerned that hazardous wastes could migrate
beyond the injection zones over the long term, a problem that could be detected only by groundwater monitoring.
(Sources: U.S. General Accounting Office, Hazardous Waste: Controls over Injection Well
Disposal Operations [1987]; Office of Technology Assessment, Technologies and Management Strategies for Hazardous Waste Control [Washington, D.C.: March 1983], 195.)
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