Man and Nature: a story of the search for oil
D. Indumathi, The Institute of Mathematical Sciences, Chennai

All of us know that modern life is literally driven by the demand for fuel. Fuel to move vehicles is petrol and diesel, and fuel for cooking is gas. All these are got from natural resources available in the Earth called oils. The oil that is extracted has been made by the natural crushing of trees and plants over thousand of years so that they slowly turn to fuel. Hence these are called fossil fuels.
The oil is usually mixed with gas (such as methane and cooking gas) and exists as an underground lake. When a pipe is drilled down to this level, the oil naturally gushes up to the surface. It is collected and refined to separate it into asphalt/tar for roads, diesel and petrol for vehicles, kerosene and gas for cooking and other useful substances such as petroleum jelly.
All nations in the world demand more and more oil to drive their people to drive their economy. India has also seen a many-fold increase in the number of vehicles on the roads. Therefore, the search for oil has moved from the land to just off-shore, and now increasingly, to deep under the seas.
These searches (or explorations) use very sophisticated technology such as remote control with robots and precision equipment. With such advances also comes the risk of drilling deep under the ocean waters which are the home to a large variety of fish, mammals and other exotic creatures.  The seas are also the source of food for people.
This is the story of one such exploration and its consequences. It happened in the Gulf of Mexico, off the coast of eastern United States (USA).
Oil exploration was going on in the sea. An oil rig is a platform on the surface of the sea from where the oil is drilled. All the control mechanisms are on the rig. A pipe is sent deep down to the sea bed to look for oil under the ocean floor. Normally, exploratory pipes are used to study the possibility of finding oil and then the oil is tapped.  As the exploration began, methane gas under high pressure shot up the pipe to the surface and caught fire on 20 April. This caused an explosion on the oil rig, called Deepwater Horizon, which then sank two days later.
Since the pipe was broken and damaged, oil started to leak directly from the pipe into the sea. Since oil is lighter than water, the oil (gushing like an underground river due to the high pressure at the sea bottom) soon reached the surface of the sea. The oil floats on water and is called an oil slick. This oil is not like cooking oil or petrol: it is sticky, dense and dark. It is not easy to remove.
Measures taken
Many attempts have been made to stop the oil leak. Many spectacular technologies have been tried, with all operations at the sea bed remote-controlled from the surface. Some methods failed, and some worked partially.
First of all, all such wells have a blow-out prevention device that should automatically go off to close a well when the pipes begin to leak or gush uncontrollably. This device did not work. Under-water robots were sent to try and activate it, but failed.
Right now, a substitute rig called the Driller III is drilling a relief well to try and re-route the oil from the old broken drill pipe into a new one. This is expected to take a few months.
On 7 May, a cap was fitted to the broken pipe to capture the oil as it leaks and rises to the surface (since it is lighter than water). But it didn't work either.
On 14 May, a small oil riser (pipe) was lowered down to the end of the original one. The leaking pipe is quite wide (21 inches in diameter). The small pipe (4 inches in diameter) was inserted into the leaking end of the big pipe. The mismatch in the sizes causes a leak all around which was sealed with a rubber diaphragm. The oil could now be pumped up through the smaller pipe. The idea was to collect the oil gushing out and so reduce the pressure at the broken end.
About 22,000 barrels of oil was collected and then the pipe was removed to try and shut down the well again.
On 26 May, work began to shut down the well. Mud was pumped from new ships down the borehole to suppress the upward flow of oil. The mud, when pumped fast enough, was expected to choke and "kill" the well. This also did not work, since the gas pressure was very high.
On 4 June, robots were used to cut through the old riser (pipe) using hydraulic shears. A containment cap was lowered on to the cut end and secured. Four vents or holes in the cap allowed half the oil to esape.  Otherwise the oil pressure would break the seal between the cap and the riser. 
About 10,000 barrels a day are now being pumped through the new pipe to a tanker on the surface. The oil leaking through the holes into the sea is estimated at about 19,000 barrels of oil per day. Some estimates put the leakage as two or even three times larger.
To understand the scale of this, a tank of dimensions 10 m length, 10 m width and 10 m height (a cube with each side 10 m) has a volume of 1000 cubic metres or one million litres. This corresponds to about 6000 barrels.
On June 16, oil and gas started to flow through a second containment system connected directly from the blow-out preventer to the surface service platform.
Damage to the environment 
The oil soon reached land. To prevent it contaminating the beaches, more than 6 km of booms were placed along the coast, especially along the nearby Mississippi river delta. However, the oil did reach the coast and contaminate the beaches by the first week of May.
Apart from damage to beaches and rivers, the presence of such a vast quantity of oil on the surface of the sea also causes problems to fish and birds. Many water birds like terns and pelicans have been seen completely covered in the dark oil. This must have happened when they plunged into the water, trying to catch fish. Once their feathers are so oily and sticky, they can no longer fly. Many of them have since died. 
Other animals that live on or close to the sea surface such as turtles have also been sighted, covered in the oil. The turtles were on their way to nesting sites on nearby beaches. The damage to creatures living deep underwater is still not known.
Ecology
More than 400 types of birds and animals living in the islands and marshlands nearby are at risk, including the endangered Kemp's Ridley turtle. For the turtles, their nesting grounds are the beaches of the Gulf of Mexico and they are all crossing the Gulf to reach the coast.
In the listing of those creatures most at risk, about 34,000 birds have been counted, including gulls, pelicans, roseate spoonbills, egrets, terns, and blue herons. There are more than 15000 species of sea life in the Gulf of Mexico, in the region of the oil spill. These include bluefin tuna, sea turtles, dolphins and other mammals.
The oil could harm fish directly, and microbes used to consume the oil would reduce the amount of oxygen in the water. Further, the natural gas that is being emitted along with the oil has lots of methane which can also reduce the oxygen levels and suffocate marine life.  It could dissolve in the water to produce benzene and other toxic compounds. Coral reefs may also get covered in oil.
It is possible the Gulf Stream sea currents may spread the oil into the Atlantic Ocean. The oil could then threaten the environment in the east coast of the United States. Apart from destroying the wild-life, it could also threaten the fishing industry in these parts.
It could take the ecosystem years and possibly decades to recover from such a disaster. Many other earlier oil spills, including spills in environments similar to the US Gulf coast, continue to cause great environmental damage for years, or even decades.
Rescue operations
Many organisations are involved in relief and rescue of birds and animals coated with the oil or injured by swimming in it.
Cleaning crew are also using tractors to rake up oil globs and tar to clean up the white beaches of the Gulf. One such cleaning crew are seen cleaning the beach in the town of Pensacola, Florida, in the picture.
Concerned citizens have been working on a war-footing to try and help the animals found in distress. In addition, many U.S.  national organisations are listing the details of the effect of the oil spill on the environment. This includes estimating the amount of oil spilling out per day, the number of dead and injured animals and birds, and the damage to beaches and people living along the coast.
More than one hundred sea turtles which were distressed due to being covered in oil are in rehabilitation centres. More than 50 dolphins have been found stranded (washed ashore), either injured or dead. Sperm whales are the only endangered resident cetacean in the Upper Gulf of Mexico. One sperm whale was found washed ashore, dead.
In all cases, investigating agencies such as the US National Oceanic and Atmospheric Administration (NOAA) check whether the death or injury is due to the leaking oil. In many cases, the animal is clearly seen to be heavily oiled.
At the Fort Jackson Bird Rehabilitation Center, brown pelicans are being treated to remove the sticky oil. The front cover of the magazine shows the oiled birds while the back cover shows them after receving the oil removing treatment and their baths. More than 600 birds have been cared for at this centre. The pelicans' true colors show after their bath. The birds will recuperate at the center for several days before being released from the eastern side of Florida.
The world is waiting to see if the efforts to cap the well---or divert the oil with an alternate pipe line---will be successful. Various kinds of technology has been, and is being used, to achieve this. Even if the efforts to close the leak succeed early, there are millions of litres of oil in the sea. The short and long term effects of this oil on the environment, on the coast, on sea-life, are expected to be tremendous.  Various technologies may also be developed to help contain these adverse effects or even to prevent spills in the future.
However, this is the right time to ask ourselves the question, "Why do we dig for oil in such risky places?" The risk of digging deep-underground is not only to the people working on the rigs, but to all life, both human and others. Even if you must dig off-shore (deep under the sea), safety is a primary criterion: no company must try to save time or money during suchan operation. In fact, it can affect every part of the Earth,  both land and sea. Why then this greed for more oil? Can we decide that we can live our lives in such a way that we depend less and less on this completely natural but very unforgiving fuel? Let us be good not only to ourselves but to every plant and animal on this Earth. Let us decide to stop polluting the Earth just in order to travel to every last corner of it.
-- With graphics from the Guardian newspaper