Ecological Management factors associated with Offshore Oil and Gas Extraction

How Is Crude Oil Extracted•Offshore oil production accounts for about 30 % of the total world oil production

• Offshore gas production for about half of the world production of natural gas.

•8,300 fixed or floating offshore platforms worldwide in 1999.

(U.S. National Research Council ; NRC)

•More than 6,500 offshore oil and gas installations worldwide (The UNEP Offshore Oil and Gas Environment Forum; OEF),

•about 4,000 of which are in the U.S. Gulf of Mexico,• 950 in Asia, •700 in the Middle East, and •400 in Europe.

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Oil and Gas Rigs

• These structures are, in many cases, movable. What is more, they can float while being moved, and often while drilling. Further, offshore rigs have drilled in waters over 7,500 feet (over 2,200 meters) deep and as far as 200 miles (over 300 kilometers) from shore". It should also be noted that the lifetime of a rig is generally about 20 years. At the end of that time, unless it is re-used or redeveloped, it must be decommissioned.

The major potential environmental effects from offshore drilling

• Discharge of wastes, including drilling fluids (also referred to as drilling muds), drill cuttings and produced formation water.

• The decommissioning of platforms/rigs is also a potential environmental problem.

SHIP'S DESIGN

• Single hull is a ship construction term. In tankers with single hulls, oil in the cargo tanks is separated from the seawater only by a bottom and a side plate. Should this plate be damaged as a result of a collision or stranding, the contents of the cargo tanks risks spilling into the sea.

• In double hull tankers the cargo tanks are surrounded with a second internal plate which is at a sufficient distance from the external plate (generally 1.5-2 metres) to safeguard cargo tanks from damage and thus reduce the risk of oil pollution. The double hull construction incorporates both double bottoms and double sides.

• In 1992, the MARPOL Convention was amended to make it mandatory for tankers of 5,000 dwt and more (ships ordered after 6 July 1993) to be fitted with double hulls.

• The requirement for double hulls that applies to new tankers has also been applied to existing ships under a programme that began in 1995

• All tankers have to be converted (or taken out of service) when they reach a certain age (up to 30 years old).

•An additional possible measure is to limit the size of individual tanks within ships so that spills that occur at least are smaller.

•The U.S. has banned single hull-vessels in their waters and has stronger liability legislation in their Oil Polllution Act.

MAINTENANCE & SHIP OWNER RESPONSIBILITY

COMPETENT CREW NAVIGATIONAL AIDS AND ON BOARD EQUIPMENT • Better navigational equipment — for example, electronic charting — is needed. All ships must have

radar systems to improve navigation (large ships must have two systems that operate independently). In busy shipping corridors, traffic separation schemes and vessel traffic control are required to reduce the risk of a collision. In some areas, mandatory pilotage should be introduced.

• High-standard fire-fighting equipment must be available and strict fire safety regulations apply on board.

• Monitoring and control equipment should be installed on ships so that discharged oil-water mixtures can be traced back to the ship that was carrying the oil.

SURVEILLANCE • The purposes of surveillance is to function as a deterrent from discharging ship-generated wastes

altogether, as a means of detection of discharges already made, and as a tool to combat, as effectively as possible the spills that have been detected. Airborne surveillance which increases the ship's risk of being caught in the process of making illegal discharges can be an effective measure to prevent discharges and thus reduce marine pollution from shipping. In the future, airborne surveillance on a regional scale should be introduced in more areas, particularly in the MARPOL Special Areas (as is already the case in the Northeast Atlantic and the Baltic Sea).

INSPECTIONS • Frequent inspection of ships, particularly older ones, are imperative. Since 1995 all tankers and bulk

carriers aged five years and over have been subject to a specially enhanced inspection programme which is intended to ensure that any deficiencies — such as corrosion or wear and tear resulting from age or neglect — are detected.

RECEPTION FACILITIES • Better facilities are needed in ports for ships to leave their oily liquid waste and solid oily waste. In

MARPOL Special Areas, such port reception facilities are required. CARGO OWNER AND OIL CONSUMER RESPONSIBILITY

At Sea : Contingency plans and response techniques

CONTINGENCY PLANS As summarized by Environment Canada, a contingency plan “is a plan for actionprepared in anticipation of an oil spill. “ Contingency plans are essential because theyestablish practical plans of action for all types of oil spills so that, when spills do occur,a quick response can minimize the damage. The first step in developing a plan is tolearn as much about the area as possible. Regardless of the geography or the size ofan area, contingency plans normally include:

• identification of authority and a chain of command;

• a list of persons and organizations that must be immediately informed of a spill;

• an inventory of available trained spill personnel and spill response equipment;

• a list of jobs that must be done (in order of priority);

• a communication network to coordinate response;

• probable oil movement patterns under different weather conditions; and

• sensitivity maps and other technical data.

Planners need to know about:

• important or sensitive physical and biological resources within or near the area, such as marshes, unusual flora (plant life) and wildlife resources such as fish, shellfish, marine mammals and birds;

• important habitat areas required by particular species for spawning, feeding or migration;

• tides, currents and local climatic conditions, such as wind and severe weather patterns;

• shoreline characteristics; and

• proximity to roads, airports, trained response personnel, oil spill clean-up equipment, etc."

RESPONSE TECHNIQUES • As summarized by International Tanker Owners Pollution Federation Ltd (

ITOPF), "there are two approaches for responding to marine oil spills at sea:

• the enhancement of natural dispersion of the oil by using dispersant chemicals, and

• containment and recovery of oil using booms and skimmers.

Sorbent materials may be useful in the final stages of clean up as a polishing tool. (Once oil strands on shore, a shoreline clean-up will be necessary.)

Despite continuing research, there has been little change in thefundamental technology for dealing with oil spills. Alternative techniques are constantly being sought and old techniquesre-assessed.

Two techniques currently receiving fresh attention are in-situ burningand the enhancement of the natural biodegradation of oil through theapplication of micro-organisms and/or nutrients

Aerial reconnaissance

Also, according to ITOPF:

• is an essential element of effective response to marine oil spills. It is used for assessing the location and extent of oil contamination and verifying predictions of the movement and fate of oil slicks at sea.

• Aerial surveillance provides information facilitating deployment and control of operations at sea, the timely protection of sites along threatened coastlines and the preparation of resources for shoreline clean-up. Observation can be undertaken visually or by use of remote sensing systems.

On Land : Contingency plans and response techniques

Regardless of the geography or the size of an area, contingency plans on land are similar to those for “At Sea” and in addition:

RESPONSE TECHNIQUES • "Given the difficulties of cleaning up oil at sea, many oil spills result in

contamination of shorelines. The oil which reaches the coast generally has the greatest environmental and economic impact. It also determines to a large extent the political and public perception of the scale of the incident, as well as the costs.

• It is important to start removing oil promptly from contaminated shorelines because as time passes and the oil weathers, it will stick more and more firmly to rocks and sea walls, and may become mixed with or buried in sediments.

• Shoreline clean-up is usually straightforward, however, and does not normally require specialised equipment. Reliance is frequently placed on locally-available equipment and manpower, rather than specialised equipment.

• Good organisation and management are the key to effective clean-up. Poorly thought out and uncoordinated clean-up efforts usually result in inefficient use of resources and excessive quantities of waste for disposal." (ITOPF)

Initial clean-up responses to a spill at sea are often based upon the use of dispersant chemicals or the containment and recovery of oil using booms

and skimmers

Whilst these techniques can be of use in the right circumstances, there are manydifficulties associated with employing them effectively. • The type of oil and concerns over potential impacts of dispersed oil can preclude

dispersant use. For example, they are not effective against many commonly transported oils which have a high viscosity, and soon become ineffective against lighter oils because natural weathering processes or the formation of water-in-oil emulsions greatly increases oil viscosity, often very quickly (a few hours to one to two days).

• The application of dispersant to treat large quantities of spilled oil also requires specialised equipment and extensive logistical support. Containment and recovery is limited by sea conditions and the relatively small oil encounter rate which the available systems can achieve.

Together, these factors usually mean that only a small fraction of a major spill can be dealt with at sea, and it is almost inevitable that oil will threaten coastal resources.

••• Protective strategies are seldom employed to the extent possible and it will usually be necessary to mount a shoreline response operation. Priorities for protection and clean-up will need to be agreed and care must be taken to ensure that the techniques selected do not do more damage than the oil alone.

• The disposal of oil and debris may become a major problem both during and after a clean-up operation. Several disposal options are however available.

The U.S. EPA summarizes as follows: "Mechanical containment or recovery equipment includes a variety of:

• booms, barriers, and skimmers, as well as natural and synthetic sorbent materials. (A sweep system is a combination skimmer and boom attached to a ship or a small boat.)

• Mechanical containment is used to capture and store the spilled oil until it can be disposed of properly. ”

Chemical and biological methods can be used in conjunction with mechanical means for containing and cleaning up oil spills .

• Dispersants and gelling agents are most useful in helping to keep oil from reaching shorelines and other sensitive habitats.

• Biological agents have the potential to assist recovery in sensitive areas such as shorelines, marshes, and wetlands. Research into these technologies continues to improve oil spill cleanup.

Physical methods are used to clean up shorelines. • Natural processes such as evaporation, oxidation, and biodegradation can start

the cleanup process, but are generally too slow to provide adequate environmental recovery.

• Physical methods, such as wiping with sorbent materials, pressure washing, and raking and bulldozing can be used to assist these natural processes.

• Scare tactics are used to protect birds and animals by keeping them away from oil spill areas. Devices such as propane scare-cans, floating dummies, and helium-filled balloons are often used, particularly to keep away birds."

Shoreline clean-up methods (see, e.g., U.S. EPA, NOAA + NOAA and USCG, ITOPF, and Environment Canada):

• No action (when a shoreline is very remote or inaccessible, when natural removal rates are fast, or clean-up activities will do more harm than if the oil is left to be removed by natural processes)

• Natural recovery (evaporation, oxidation, and biodegradation can start the clean-up process, but are generally too slow to provide adequate environmental recovery)

• Application of barriers or berms • Physical herding • Manual oil removal/cleaning • Mechanical oil removal • Use of sorbents (passive collection) • Use of vacuum • Removal of oily debris • Sediment reworking/tilling (raking, bulldozing) • Vegetation cutting/removal • Shoreline flooding (deluge) • Ambient low-pressure or high-pressure water washing (pressure washing, flushing) • Warm-water or hot-water high-pressure washing (see also here) • Slurry sand blasting

Possible shoreline clean-up methods also include:

(however, in many countries these methods may only be used after special permission from the authorities):

• the use of solidifiers (gelling agents), • shoreline cleaning agents, • fertilizers to enhance biological remediation,

and • in situ burning.

The environmentally acceptable disposal of oil and oily waste (debris) is important

• As pointed out by EPA: "Cleanup from an oil spill is not considered complete until all waste materials are disposed of properly. The cleanup of an oiled shoreline can create different types of waste materials, including liquid oil, oil mixed with sand, and tar balls. Oil can sometimes be recovered and reused, disposed of by incineration, or placed in landfills".

• All these methods must be employed with high consideration for the environment in order to avoid new problems of air pollution or leakage of toxic substances into groundwater and rivers.

Sensitivity of coastal environments to oil:Location (where the oil is stranded) and shoreline geology, as well as type of oil that

needs to be taken care of, and of course the type and sensitivity of the biological communities (species and habitats) that are likely to be affected by the clean-up operation, are important factors in the choice of clean-up method(s) — see NOAA and EPA.

The U.S. Coastguard have listed shoreline types, from the least (low figures; at top here) to the most sensitive ones to oil pollution:

• Exposed rocky cliffs and seawalls • Wave cut rocky platforms • Fine to medium-grained sand beaches • Coarse-grained sand beaches • Mixed sand and gravel beaches • Gravel beaches/Riprap • Exposed tidal flats • Sheltered rocky shores/man-made structures • Sheltered tidal flats • Marshes

Other shore types and shallow underwater habitats are also very sensitive to oil pollution,

including:

• Mangroves (And according to ITOPF: "Leaving residual oil to weather and degrade naturally is usually recommended for sensitive shoreline types such as salt marshes and mangroves, because they have been shown to be more easily damaged by the physical disturbance caused by clean-up teams and vehicles than by the oil itself. If any cleaning is attempted, it should be carried out with specialist guidance and advice.")

• Coral reefs