Deepwater drilling is defined by the U.S. government as any offshore drilling operation that takes place more than 500 feet below the surface of the ocean. Today, many rigs are being drilled in the very hostile environments of deeper and deeper water. The Deepwater Horizon, which exploded and sank in the Gulf of Mexico in 2010 was a six mile deep well that operated in 4,130 feet of water and a recently drilled well, the Dhirubhai Deepwater KG1 off the east coast of India, has set a new world record for the deepest water depth by an offshore drilling rig in 10,411 feet of water.
The Deepwater Horizon explosion killed 11 people and injured 16 others and was the largest oil spill in human history. What has not been widely reported is that 40% of what leaked from the well was methane gas, which is 20 to 25 times more heat trapping than carbon dioxide.
What the effect of this release of methane will be and what are the long-term effects of using almost three million litres of chemical dispersants to “clean up the spill” are big unanswered questions. What we do know is that the hydrocarbons released from the Deepwater Horizon are still deep in the ocean.
Unfortunately the tragedy of the Deepwater Horizon is not an isolated incident and it now takes its place among other major tragedies such as the explosion of the Piper Alpha rig in the North Sea in 1988, which killed 167 people and the explosion of the Petrobas 36 platform, off the coast of Brazil in 2001, which killed 11.
While these major catastrophes grab the headlines, little spills from deepwater rigs caused by chronic leaks, well blowouts, drilling waste being dumped and the transport of oil, result in millions and millions of gallons of oil and waste being released into the ocean each year. Transporting oil is also a major source of pollution, both from spills and the practice of ships discharging oily ballast wastewater – the dirty water that is used to keep giant transport ships stable.
The full extent of the environmental impacts of both major and minor spills is not totally known, however by damaging and destroying habitat, interfering with how body parts function and destroying or reducing food sources, oil spills kill marine life.