EnergyBC

Environmental Impacts (more...)

The environmental hazards that are most commonly associated with offshore development are oil spills and blowouts. However, there are several other aspects of operations that must be closely monitored and regulated to ensure environmental protection. Environmental impact assessments are now standard procedure requiring approval at both the provincial and federal level before major industrial projects are allowed to proceed. The waters of Hecate Strait and the Queen Charlotte Sound are part of a diverse ecosystem to which the impacts of offshore development could have potentially devastating effects. Both the Strong et al. (2002) and RSC (2004) reports noted that several knowledge gaps in this matter exist and should be filled before the moratorium could be lifted.

Each of the four main phases of the offshore oil and gas process involve operations that can have an environmental impact.

Exploration

Seismic Surveying

- can cause behavioural modifications in some species that use use sound to communicate and navigate

Production

Rig Construction	- loss of sea floor habitat
	- on the other hand, rigs also attract fish and corals
Drilling	- drill cuttings that are deposited into the environment can contain heavy metals, drilling muds and naturally occurring radioactive materials (NORMs)
	- drilling muds are either water-based (WBM), synthetic/alternative-based (ABM) or oil-based (OBM)
	- WBMs and ABMs are released directly into the ocean, and while they are less toxic than OBMs, they can still be seen contaminating marine species such as scallops (Boudreau, 1998 in Canada, 1999; Cranford and Gordon ,1992 in Kenchington, 1997)
	- drilling wastes bury the sea floor and create an anoxic (low oxygen) environment
	- the discharge increases turbidity and creates cloudy plumes in the water column, reducing the ability of light to filter through the water
	- currently it is not possible to eliminate the presence of heavy metals from drilling discharge, and these, along with hydrocarbons, may also have an affect on some forms of marine biota
Noise	- underwater rig noise would likely be less than that generated by vessel traffic
	- even noise from supertankers is thought to be fairly negligible, although it can have some affect on marine mammals, especially the hearing of killer whales (Richardson et al., 1995)
	- airborne noise, particularly that generated by support helicopters, is more of a concern
	- the majority of BC coastal birds nest in burrows, but it has been found in other regions with cliff-nesting species that they will abandon their nests and their eggs if a helicopter gets too close
	- marine mammals will also go out of their way to avoid helicopters, which may lead to seals and sea lions abandoning their pups and not returning
	- more studies should be done to better determine the effects of helicopter noise on coastal species
Light	- it is also possible that birds are attracted to, or confused by, the lights on the offshore rigs
	- lighting on rigs cannot be modified without safety in mind

Development

Produced Water	- water from the well being drilled
	- contains additives from drilling (corrosion inhibitors, polymers, dispersants, etc.), along with compounds from the rocks through which the drilling is taking place (hydrocarbons, heavy metals, naphthalenes, NORMs)
	- non-saline, higher temperature than the surrounding water and has a different pH (acidity) (JWEL, 2001; Kenchington, 1997)
	- at the point of discharge, produced water may be toxic and may cause thermal shock
	- some studies show that the impacts of produced water are negligible between half a kilometer and two kilometers away from the discharge point (Kenchington, 1997; GESAMP, 1993; Stoemgre et al., 1995), while others argue that contamination may still be occurring at points further away than that (Lee, 2003; GESAMP, 1993; Kingston, 1992)
	- metals especially are likely to bioaccumulate
	- sessile organisms (those that don't move) are the most likely to be affected, as are those that dwell on the benthos (bottom of the sea floor)
Transportation	- oil spills from tankers have been devastating at many locations around the world

Miscellaneous

Fluid Discharges	- sewage, drainage water, small spills and leaks, run-off from the platform, etc.
Air Pollution	- combustible garbage usually gets incinerated on the drilling rig
	- other sources of combustion come from the generators, ship engines, production facilities, the burning of well-fluid during production tests, and the flaring off of gas (JWEL, 2001)
	- flared gas yields almost 30% of the total world production of gaseous hydrocarbons and is one of the biggest sources of atmospheric emissions in the world (Patin, 1999)

Decommissioning

General Decommissioning

- use of explosives may result in small fish mortality
- if portions of structures are left in place the artificial reef community can continue to survive

Further Details