Oil Spills (more...)
The aspect of oil and gas exploration that has the greatest potential for environmental damage is oil spills and blowouts. Proper controls (legislation, emergency response plans) must be in place to ensure that an effective regulatory regime can be implemented in the event of a spill. Several types of countermeasures exist to contain or minimize the negative impacts of spills, however their effectiveness is dependent on the size, composition and location of the spill. |
 |
Click here for info on the Terra Nova Oil Spill, November 2004
| History | - more than 31 million barrels of oil have been lost to spills between 1974-1997, according to the US Minerals Management Service (MMS) |
||||||||
- the largest spill in history was the July 1979 blowout of the Ixtoc-I facility in the Gulf of Mexico which released more than three million barrels of oil before it was finally brought under control in 1980 |
|||||||||
|
- the largest tanker spill was the more than two million barrels of oil released into the West Indies by the Atlantic Empress |
||||||||
- the well-known Exxon Valdez spill in the Prince William Sound in Alaska in 1989 was 260,000, and is only 34th largest worldwide |
|||||||||
- the amount of damage done by a spill depends on, among other things, the type of chemicals involved (oils vs. gas/condensates that break down quickly), the location of the spill (near shore or far from shore), the winds and tides (will either spread or contain the spill), etc.
|
|||||||||
| Improvements | - spill frequencies and volumes have been decreasing over the past several decades, despite an increase in oil and gas production and transportation (RSC, 2004; JWEL, 2001; Shrimpton, 2004) |
||||||||
| - offshore oil and gas production is only responsible for 4% of the petroleum in the world's oceans (NRC, 2002) | |||||||||
- from 2002-2003, there were only 13 spills large than 10L offshore of Newfoundland and only 12 spills larger than 10L offshore of Nova Scotia, the largest of which was 23,700 L (C-NOPB, CNSOPB)
|
|||||||||
| Blowouts | - occur when control is lost over pressure and flow of the well | ||||||||
| - drilling muds, gas and/or oil flow to the surface | |||||||||
| - usually a relief well is drilling to regain control that intersects the original well | |||||||||
- the chance of a blowout is small, only 1/6,666 for exploratory wells and 1/40,000 for production wells (RSC, 2004)
|
|||||||||
| Impacts of Spills | - impacts vary depending on the composition of spilled oil/gas and the environment in which the spill occurs | ||||||||
- hydrocarbons have a tendency to accumulate at interfaces such as the surface of the water, the seabed and on the beach, so creatures that in these regions are particularly susceptible to contamination |
|||||||||
- some organisms that are particularly affected are:
|
|||||||||
- and the organisms are affected through:
|
|||||||||
| Impact on Fisheries | - open-ocean species such as salmon, herring and tuna are less affected by spills than bottom-feeding species such as cod, halibut and flounder | ||||||||
| - other species at risk are the bottom- and beach-dwelling crustaceans and bivalves (clams, oysters, scallops, crabs, lobsters, shrimp) | |||||||||
- species that return to spawn in fresh water are likely at risk, as are those that have eggs that drift in the currents or lie on the bottom of the ocean
|
|||||||||
| Countermeasures | - spills on the surface of the ocean can sometimes be contained by floating booms | ||||||||
| - dispersants are chemicals that can be sprayed over the spill to speed up the process of breaking down the oil | |||||||||
| - bacteria can also be used in the same manner | |||||||||
| - shorelines can be cleaned by hand, although this is extremely time-consuming | |||||||||
| - occasionally companies will ignite the oil to burn it off | |||||||||
- clean-up efforts are generally not particularly successful, with only 5-15% of the oil ever being recovered (Spies et al., 1996)
|
|||||||||
| OSRIS | - computer-based modeling web site developed by the BC government to determine the most sensitive coastline areas
|
||||||||
| Emergency Response Plans | - currently BC does not have a regulatory process for dealing with offshore oil and gas because of the existing moratorium, however the Ministry of Land, Water and Air Protection is responsible for the environment, while current marine oil spills are handled under the environmental emergency management program | ||||||||
| - when a spill occurs, the operator is responsible for the cost of the cleanup |
| References | Offshore Oil & Gas Moratorium | Links | About EnergyBC | © MJ Whiticar, Biogeochemistry |  |