Restoration of Land-Based Sites
After 15-30 years of production, most oil or natural gas wells reach their economic limit and need to be shut down. Dry holes – wells that do not produce as expected – must also be addressed. Today, oil and natural gas companies consider site restoration a critical operations activity. Teams of environmental and engineering professionals, and skilled equipment operators handle restoration to bring sites back to original or better condition.
The restoration of land-based wells is discussed below. Restoration of offshore sites will be discussed separately.
About 17,000 land-based sites are closed and restored every year. This involves filling the casing with cement and removing the wellheads, pump jacks, tanks, pipes, facilities and equipment. Then the wellbore is plugged to prevent underground fluids from getting into groundwater. Waste-handling pits, if present, are properly closed, and the location is restored to near-original condition.
Bioremediation - At some sites, the soil can become contaminated with hydrocarbon molecules. In the past, these sites were often addressed by digging up the soil and moving it to a special landfill. Today, many sites are restored using bioremediation--the stimulation or placement of oil-eating microorganisms in the soils to digest hydrocarbons. This is a very effective and natural approach that causes minimal disturbance to the land while reducing landfill requirements.
Recycling - Advanced technology isn't always the best answer. Sometimes a creative, low-tech approach is the right answer. In Pennsylvania, sediment that collects at the bottom of oil storage tanks is used as a component in paving mix on local roads. This saves costs for the producers and reduces landfill requirements. Drill cuttings from drilling operations can be mixed with cement to produce bricks The cuttings produced from just one well can make up to 700,000 new bricks!»next