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Gulf of Mexico Deep Water Horizon Oil Spill

The Deepwater Horizon oil spill  is an oil spill in the Gulf of Mexico which flowed for three months in 2010. The impact of the spill continues since the well was capped. It is the largest accidental marine oil spill in the history of the petroleum industry. The spill stemmed from a sea-floor oil gusher that resulted from the April 20, 2010 Deepwater Horizon drilling rig explosion. The explosion killed 11 platform workers and injured 17 others. 

At approximately 9:45 p.m. CDT on April 20, 2010, methane gas from the well, under high pressure, shot all the way up and out of the drill column, expanded onto the platform, and then ignited and exploded. Fire then engulfed the platform. Most of the workers escaped the disaster by lifeboats or were airlifted out by helicopter, but eleven workers were never found despite a three-day Coast Guard search operation, and are presumed to have died in the explosion. Efforts by multiple ships to douse the flames were unsuccessful. After burning for approximately 36 hours, the Deepwater Horizon sank on the morning of April 22, 2010.

Federal authorities banned commercial and recreational fishing in a large stretch of water off four states, from the mouth of the Mississippi River off Louisiana to western parts of the Florida Panhandle.

On July 15, the leak was stopped by capping the gushing wellhead.

Long-term impact of Gulf of Mexico oil spill remains unclear. The oil spill will have long-term effects on businesses the environment, wildlife and jobs in the Gulf Coast region.

The Effects of Oil on Wildlife

Oil affects wildlife by coating their bodies with a thick layer. Many oils also become stickier over time (this is called weathering) and so adheres to wildlife even more. Since most oil floats o nthe surface of the water it can effect many marine animals and sea birds. Unfortunately, birds and marine mammals will not necessarily avoid an oil spill. Some marine mammals, such as seals and dolphins, have been seen swimming and feeding in or near an oil spill. Some fish are attracted to oil because it looks like floating food. This endangers sea birds, which are attracted to schools of fish and may dive through oil slicks to get to the fish.
Oil that sticks to fur or feathers, usually crude and bunker fuels, can cause many problems. Some of these problems are:

•hypothermia in birds by reducing or destroying the insulation and waterproofing properties of their feathers;
•hypothermia in fur seal pups by reducing or destroying the insulation of their woolly fur (called lanugo). Adult fur seals have blubber and would not suffer from hypothermia if oiled. Dolphins and whales do not have fur, so oil will not easily stick to them;
•birds become easy prey, as their feathers being matted by oil make them less able to fly away;
•marine mammals such as fur seals become easy prey if oil sticks their flippers to their bodies, making it hard for them to escape predators;
•birds sink or drown because oiled feathers weigh more and their sticky feathers cannot trap enough air between them to keep them buoyant;
•fur seal pups drown if oil sticks their flippers to their bodies
•birds lose body weight as their metabolism tries to combat low body temperature;
•marine mammals lose body weight when they can not feed due to contamination of their environment by oil;
•birds become dehydrated and can starve as they give up or reduce drinking, diving and swimming to look for food;
•inflammation or infection in dugongs and difficulty eating due to oil sticking to the sensory hairs around their mouths;
•disguise of scent that seal pups and mothers rely on to identify each other, leading to rejection, abandonment and starvation of seal pups; and
•damage to the insides of animals and birds bodies, for example by causing ulcers or bleeding in their stomachs if they ingest the oil by accident.


Oil does not have to be sticky to endanger wildlife. Both sticky oils such as crude oil and bunker fuels, and non-sticky oils such as refined petroleum products can affect different wildlife. Oils such as refined petroleum products do not last as long in the marine environment as crude or bunker fuel. They are not likely to stick to a bird or animal, but they are much more poisonous than crude oil or bunker fuel. While some of the following effects on sea birds, marine mammals and turtles can be caused by crude oil or bunker fuel, they are more commonly caused by refined oil products.

Oil in the environment or oil that is ingested can cause:

•poisoning of wildlife higher up the food chain if they eat large amounts of other organisms that have taken oil into their tissues;
•interference with breeding by making the animal too ill to breed, interfering with breeding behaviour such as a bird sitting on their eggs, or by reducing the number of eggs a bird will lay;
•damage to the airways and lungs of marine mammals and turtles, congestion, pneumonia, emphysema and even death by breathing in droplets of oil, or oil fumes or gas;
•damage to a marine mammal's or turtle's eyes, which can cause ulcers, conjunctivitis and blindness, making it difficult for them to find food, and sometimes causing starvation;
•irritation or ulceration of skin, mouth or nasal cavities;
•damage to and suppression of a marine mammal's immune system, sometimes causing secondary bacterial or fungal infections;
•damage to red blood cells;
•organ damage and failure such as a bird or marine mammal's liver;
•damage to a bird's adrenal tissue which interferes with a bird's ability to maintain blood pressure, and concentration of fluid in its body;
•decrease in the thickness of egg shells;
•stress;
•damage to fish eggs, larvae and young fish;
•contamination of beaches where turtles breed causing contamination of eggs, adult turtles or newly hatched turtles;
•damage to estuaries, coral reefs, seagrass and mangrove habitats which are the breeding areas of many fish and crustaceans, interfering with their breeding;
•tainting of fish, crustaceans, molluscs and algae;
•interference with a baleen whale's feeding system by tar-like oil, as this type of whale feeds by skimming the surface and filtering out the water; and
•poisoning of young through the mother, as a dolphin calf can absorb oil through it's mothers milk.

Animals covered in oil at the beginning of a spill may be affected differently from animals encountering the oil later. For example, early on, the oil maybe more poisonous, so the wildlife affected early will take in more of the poison. The weather conditions can reduce or increase the potential for oil to cause damage to the environment and wildlife. For example, warm seas and high winds will encourage lighter oils to form gases, and will reduce the amount of oil that stays in the water to affect marine life.

The impact of an oil spill on wildlife is also affected by where spilled oil reaches. 

 

 

 

 

 

 

 

Credit: The Times Picayune

Offshore Drilling 

Drilling offshore dates back as early as 1869, when one of the first patents was granted to T.F. Rowland for his offshore drilling rig design. This rig was designed to operate in very shallow water, but the anchored four legged tower bears much resemblance to modern offshore rigs. It wasn't until after World War II that the first offshore well, completely out of sight from land, was drilled in the Gulf of Mexico in 1947. Since then, offshore production, particularly in the Gulf of Mexico, has resulted in the discovery and delivery of a great number of large natural gas and oil deposits. There are 3859 active platforms in The Gulf of Mexico .

There are two basic types of offshore drilling rigs: those that can be moved from place to place, allowing for drilling in multiple locations, and those rigs that are permanently placed. Moveable rigs are often used for exploratory purposes because they are much cheaper to use than permanent platforms. Once large deposits of hydrocarbons have been found, a permanent platform is built to allow their extraction.

Types of offshore oil and gas structures include: 

1, 2) conventional fixed platforms (deepest: Shell’s Bullwinkle in 1991 at 412 m/1,353 ft GOM); 

3) compliant tower (deepest: ChevronTexaco’s Petronius in 1998 at 534 m /1,754 ft GOM); \

4, 5) vertically moored tension leg and mini-tension leg platform (deepest: ConocoPhillips’ Magnolia in 2004 1,425 m/4,674 ft GOM); 

6) Spar (deepest: Dominion’s Devils Tower in 2004, 1,710 m/5,610 ft GOM); 

7,8) Semi-submersibles (deepest: Shell’s NaKika in 2003, 1920 m/6,300 ft GOM); 

9) Floating production, storage, and offloading facility (deepest: 2005, 1,345 m/4,429 ft Brazil); 

10) sub-sea completion and tie-back to host facility (deepest: Shell’s Coulomb tie to NaKika 2004, 2,307 m/ 7,570 ft).

Deepwater Horizon

The DEEPWATER HORIZON was a Reading & Bates Falcon RBS8D design semi-submersible drilling unit capable of operating in harsh environments and water depths up to 8,000 ft (upgradeable to 10,000 ft) using 18¾in 15,000 psi BOP and 21in OD marine riser.

Rig Type

5th Generation Deepwater

Design

Reading & Bates Falcon RBS-8D

Builder

Hyundai Heavy Industries Shipyard, Ulsan, South Korea

Year Built

2001

Classification

ABS

Flag

Marshall Islands

Accommodation

130 berths

Helideck

Rated for S61-N helicopter

Moonpool

21 ft x 93 ft

Station Keeping

Dynamically Positioned

Max Drill Depth

30,000 ft / 9,144 m

Max Water Depth

8,000 ft / 2,438 m

Operating Conditions

Significant Wave: 29 ft;@ 10.1 sec; Wind: 60 knots; Current: 3.5 knots

Storm Conditions

Significant Wave: 41 ft @ 15 sec; Wind: 103 knots; Current: 3.5 knots

Technical Dimensions

Length

396 ft

121 m

Breadth

256 ft

78 m

Depth

136 ft

41 m

Operating Draft

76 ft

23 m

Ocean Transit Draft

29 ft

9 m

VDL - Operating

8,816 st

8,000 mt

Capacities

Liquid Mud

4,435 bbls

24,900 cu ft

705 cu m

Drill Water

13,076 bbls

73,415 cu ft

2,078 cu m

Potable Water

7,456 bbls

41,862 cu ft

1,185 cu m

Fuel Oil

27,855 bbls

156,392 cu ft

4,426 cu m

Bulk Mud

13,625 cu ft

386 cu m

Bulk Cement

8,175 cu ft

231 cu m

Sack Material

10,000 sacks

Drilling Equipment

Derrick

Dreco 242 ft x 48 ft x 48 ft, 2000 kips GNC

Drawworks

Hitec active heave compensating drawworks, 6900 hp rated input power continuous, 2in drilling line

Motion Compensator

Hitec ASA Active Heave Compensator, 13.7 ft stroke, 500 st operating, 1000 st locked

Top Drive

Varco TDS-8S, 750 st, 1150 hp with PH-100 pipe handler

Rotary

Varco RST, 60.5in opening, 1000 st

Pipe Handling

2 x Varco PRS-6i Pipe Packers; Varco AR-3200 Iron Roughneck

Mud Pumps

4 x Continental Emsco FC-2200, 7500 psi

Shale Shakers

7 x Brandt LCM-2D CS linear motion / cascading shakers

Desander

2 x Brandt SRS-3 with 6 x 12in cones

Desilter

Brandt LCM-2D/LMC with 40 x 4in cones over one linear motion shaker, 2400 gpm

Mud Cleaner

See Desilter

BOP

2 x Cameron Type TL 18¾in 15K double preventers; 1 x Cameron Type TL 18¾in 15K single preventer; 1 x Cameron DWHC 18¾in 15K wellhead connector

LMRP

2 x Cameron DL 18¾in 10K annular; 1 x Cameron HC 18¾in 10K connector

Diverter

Hydril 60 with 21¼in max bore size, 500 psi WP and 18in flowline and two outlets

Control System

Cameron Multiplex Control System

Riser

Vetco HMF-Classs H 21in OD riser; 90 ft long joints with C&K and booster and hydraulic supply lines

Riser Tensioners

6 x Hydralift Inline, 50f t stroke, 800 kips each

Guideline Tensioners

N/A

Podline Tensioners

N/A

Choke & Kill

Stewart & Stevenson 3-1/16in, 15K, with 2 x adjustable chokes and 2 x hydraulic power chokes

Cementing

Halliburton (third party equipment)

Machinery

Main Power

6 x Wartsila 18V32 rated 9775 hp each, driving 6 x ABB AMG 0900xU10 7000 kW 11,000 volts AC generators

Emergency Power

1 x Caterpillar 3408 DITA driving 1 x Caterpillar SR4 370 kW 480 volts AC generator

Power Distribution

8 x ABB Sami-Megastar Thruster Drives, 5.5 MW and 6 x GE Drilling Drive Lineups 600 V 12 MW

Deck Cranes

2 x Liebherr, 150 ft boom, 80 mt @ 35 ft

Thrusters

8 x Kamewa rated 7375 hp each, fixed propeller, full 360 deg azimuth

Credit: NOAA.NASA,EPA,The Gulf Restoration Network, BP, Transocean, Acting Outlaws,The Times Picayune, Time Magazine