The accumulation of scientific knowledge regarding the environmental impact of oil well drilling in North America has tended to lag behind the actual drilling of oil wells. Most attempts to regulate the industry have relied on hindsight: the need for regulation becomes apparent only after undesirable events occur. The problems associated with earth that supplies wells and springs—provide a case in point.
When commercial drilling for oil began in North America in the mid-nineteenth century, regulations reflected the industry’s concern for the purity of the wells’ oil. In 1893, for example, regulations were enacted specifying well construction requirements to protect oil and gas reserves from contamination by fresh water. Thousands of wells were drilled many drinking-water wells near the oil well sites began to produce unpotable, oil-contaminated water.
The reason for this contamination was that groundwater is usually found in porous and permeable geologic formations near the earth’s surface, whereas petroleum and unpotable saline water reservoirs are generally found in similar formations but at greater depths. Drilling a well creates a conduit connecting all the formations that it has penetrated. the groundwater formations; now, however, large metal pipe casings, set in place with cement, are used.
Regulations currently govern the kinds of casing and cement that can be used in these practices; however, “the hazards of insufficient knowledge” persist. For example, the long-term stability of this way of protecting groundwater is unknown. The protective barrier may fail due to corrosion of the casing by certain fluids flowing up contamination also occurred, prompting international concern over oil exploration and initiating further attempts to refine regulations.
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