Offshore drilling typically refers to the act of extracting underground resources which lie underwater near the shoreline. Most commonly, the term is used to describe oil extraction off the coasts of continents, though the term can also apply to drilling in lakes and inland seas.
The first offshore drilling was done at the end of the 19th century in Baku at the Bibi-Eibat field. In 1896 oil companies began drilling from wharves built out over the Pacific Ocean at Summerland field, California.
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Bombay High Oil field, Bassein Oil Field, and Aliabet Oil Field are the offshore oil fields in India.
1. Polluting the water:
Since the drilling for oil takes place under the ocean floor, water will always be present. As the oil is extracted from the trap, the water that is extracted with it will need to be separated and returned to the ocean.
This is referred to as ‘Produced Formation Water’ (PFW). It is necessary that the water that is returned to the ocean is clear from almost all of the oils and chemicals. The amount of petroleum hydrocarbon contained in PFW is strictly regulated.
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2. Effects of offshore drilling:
i. Accidents:
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The truth is that accidents can happen, with the main cause being human error, not the technology that is used. These accidents include leaks, spills, blowouts, barge collisions, pipeline corrosion, and explosions. For any oil spill, only 5—15 per cent can be cleaned up.
ii. Pollution:
In the drilling process, the drilling fluid is used to lubricate the drill bit as it drills through the layer of hard rock of the outer continental shelf. A toxic soup is formed when the fluid blends with rock, mud, and naturally occurring radioactive materials, which can spread thousand of metres from the rigs.
These drilling muds and cuttings as well as the produced waters contain arsenic, lead, mercury, cadmium, petroleum hydrocarbons, vanadium, copper, aluminum, chromium, zinc, polynuclear aromatic hydrocarbons, radionuclide’s and other heavy metals. All of these chemicals pose a threat to the area surrounding the rigs for as many as forty years.
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Such threats are affecting the quality of the marine water, harming the organisms that stay on the bottom of the ocean, and, ultimately, having negative impacts throughout the region, which includes changes in the abundance richness and diversity of the marine life from both the physical and toxic effects.
Draining of oil, grease, drilling fluids, lubricants, ethylene, fuels, surfactants, biocides, detergents, corrosion inhibitors, bleach, cleaning solvents, coagulants, as well as other chemicals off the rig deck have a disastrous affect on the surrounding marine environment.
3. Effects on the Environment:
The effects of offshore drilling are not simply felt by the surrounding environment, but also by the marine life. These effects have damaging consequences on the fisheries, food chain, balance of the ecosystem, health, and the enjoyment that we find in the diversity of nature.
Whenever oil is recovered from the ocean floor, other chemicals and toxic substances like mercury, lead and arsenic are often released back into the ocean. In addition, seismic waves used to locate oil can harm sea mammals and disorient whales.
One particular example of the effects that these rigs pose to the marine life that inhabits the waters around them is the sea turtle. When sea turtles come in contact with weathered oil, they become infertile. Moreover, sea turtles are attracted to light, and the lights that are situated on the rigs pose a risk to the hatchlings, because they are drawn towards the rigs where predator fish could be hiding.