The Rig and Deep Water
On April 20, 2010 Deep Water Horizon, a Transocean deep sea drilling rig – working for British Petroleum in the Gulf of Mexico on the Macondo Prospect, which is located on the Mississippi Canyon Block 252, 48 miles from the coast of Louisiana – caught fire, burned fiercely for 36 hours and then sank in 5,000′ of water. Eleven oil rig workers died and several others were severely injured. The flames from the rig fire were 200-300 feet high and visible from a distance of 35 miles when the fire was its height.
This accident is producing the largest oil slick in American history, perhaps the largest such disaster anywhere in the history of the oil industry. Oil is leaking out at 200,000 gallons per day. The oil slick tripled in size in one day, from a spill the size of Rhode Island to one as big as Puerto Rico, according to images collected from mostly European satellites and analyzed by the University of Miami. The environmental mess could be larger than the 1989 Exxon Valdez disaster, when an oil tanker spilled 11 million gallons off Alaska’s shores. No effective means for containment for the Deepwater Horizon oil slick has been found as of the date of this article.
Image: Reading and Bates RBS-8M
Deepwater Nautilus – 5th generation deep water, exploratory oil rig
Deepwater Nautilus is very similar in design to Deepwater Horizon. Deepwater Horizon is a fifth generation semi-submersible drilling rig that is designed for harsh environments and effective work to 8,000′, upgradeable to 10,000′ with maximum drill depth of 30,000′ (9144m). It was designed by Reading & Bates Falcon and built in 2001 by Hyundai Heavy Industries shipyard in South Korea. DWH is 396′ (121m) long, 256′ (78m) breadth, 136′ (41m) depth with an operating draft of 76′ (23m). Deepwater Horizon has 130 berths and is designed to operate in storm conditions with 29′ waves and 60 knot winds. It should withstand 41′ waves and winds of 103 knots without incident.
This state-of-the-art, high technology rig set the world’s record for deepest well drilled. On September 2, 2009, Deepwater Horizon drilled the Tiber oil field in the Gulf of Mexico to a measured depth of 35,055′ (10,685 m) of which 4132′ (1259) was water. The rig represents the cutting edge of deep ocean drilling technology as it can work in water up to 10,000′ depth. The rig is not moored and does not use anchors. A complete drilling spread with helicopters, support vessels and other services cost US$1,000,000 per day. The rig cost US$350,000,000 to build in 2001 and would likely cost double that to replace.
This and the following two photos of Deepwater Horizon on fire were made available by a friend and colleague who works on oil rig maintenance and safety for a major international oil company, and has often visited British Petroleum installations.
Deepwater Horizon was contracted to the operator British Petroleum, which holds a 65% interest, through 2013. Anadarko holds 25% ownership; and MOEX 2007 holds the remaining 10%. Industrial technology of this complexity is very expensive. British Petroleum has made a very large commitment to deep ocean oil exploration because there may be no large land based resources to be discovered and the demand for oil continues unabated in the USA, indeed is increasing in India and China. This rig costs US$ 500,000 per day to contract.
This rig represents the cutting edge of deep ocean drilling technology as it can work in water up to 10,000′ depth. A triple redundant computer system uses satellite data to continually reposition the giant rig using powerful thrusters. This procedure known as Dynamic Repositioning has a very low margin of error and the rig will always be within a few feet of the intended location. Without anchors, the rig is always floating and moving with the winds, currents and waves within small proscribed limits. Until this horrible accident, the safety record of this rig was exceptional.
In their 52-page exploration plan and environmental impact analysis, BP repeatedly suggested it was nearly impossible, for an accident to occur with deep exploration oil rigs that would lead to a giant crude oil spill and serious damage to beaches, fish, mammals and fisheries. ‘Unprecedented’ is BP’s oblique admission that they were caught unprepared as the Denial Box about their shoddy safety procedures seems to have been in full play. Hubris has a way of coming back to batter its author.
Diagram of a Blowout Preventer for an Oil Rig
BOPs, Explosion and Disaster
Blowout Preventers (BOPs) are the pressure control system positioned at the seabed on the uppermost, unmoving point in the well. In a serious emergency, there are multiple Panic Buttons to hit. There are also fail-safe Deadman systems should the system become automatically engaged in the worst of scenarios. As none of these systems were activated, the speed at which the explosion traveled to the surface was extreme. There was no way to deal effectively with the first few minutes of an accident of this type.
Image: Dexcel / Wikipedia
Two Oil Rig Blowout Preventers awaiting installation on a Mediterranean oil rig.
Apparently, immediately preceding the well head explosion of April 21, 2010, gas and oil got into the well head and were not detected in time to prevent an explosion. With Dynamic Positioning, the rig floats as it not securely anchored by design, the speed at which the blowout traveled upward to the surface and rig must have very rapid.
Deepwater Horizon Oil Rig Fire, April 21, 2010
At the time of the explosion, the rig had just finished cementing steel casing at depths exceeding 18,000′ (5,486 meters). The next operation would have been to suspend the well so that it could be moved to its next work location, later to return to this location to bring the well into production.
A story now circulating among industry professionals who work on these giant, high tech oil rigs is that a drill tool became stuck in the hole across the BOP which prevented the rams from operating. But this cannot be the complete story because shear rams are supposed to shear drill pipe and close the hole. Something else that was very important and yet to be identified and/or acknowledged, occurred. My contact is not the first oil industry safety professional to suspect British Petroleum of cutting corners on safety procedures, because their only operational priority in daily practice is oil production. Specifically, he suspects that BP compromised safety on this BOP as regards deck testing procedures before the BOP was sent to the undersea well head. BP has long been accused of covering up mishaps at their North Sea rigs.
Image: Originalwana / Wikimedia
Oil spill locations April 25 to May 4, 2010.
Every large floating oil rig has at least one Remotely Operated Vehicle (ROV), which are tethered miniature submarines with manipulator arms and other equipment that allow them to perform elaborate and detailed work under water. ROVs were used to explore the Titanic. In the Deep Water Horizon situation, the ROVs are deployed from nearby service ships. Using a specialized port on the BOPs and a pumping arrangement on the ROVs, attempts are ongoing to close the well which have yet to prove successful. Specialized control vessels on the surface should now be working to skim oil from the surface. But with high winds and the ever increasing magnitude of the oil leakage, this approach is chasing goals that cannot be reached. The best situation might be to pray for a bridge off down from the hole.
The Mother of All Oil Slicks
Minimum average flow rate from the well head is slightly more than 1 million gallons of oil (26,000 barrels) per day on the sea floor. As of May 2, 2010, a minimum of 12.2 million gallons of oil have spilled into the Gulf of Mexico. As high as the oil leakage is now is at 5,000 barrels or 210,000 gallons/day, it is restricted by the presence of the wellhead and kinked piping.
British Petroleum intends to drill a new well that intersects the blowing one. The challenge is to drill a new well three miles deep from a floating rig to an exact location with an acceptable target radius error of a few feet. When the target is intersected – the damaged and leaking well – a heavy fluid is pumped in that exceeds the formation’s pressure, thus causing the oil flow to stop. It will take $USD100 million and more than two months to accomplish this feat. Meanwhile, the well continues to pour oil into the ocean at increasing flow rates and an ecological disaster of unimagined proportions is upon us.
Oil Slick in the Gulf of Mexico, April 30, 2010
The Deepwater Horizon oil rig failed to cap a deep ocean well head on April 20, 2010. An horrific explosion and fire followed which consumed the oil rig in 36 hours. The oil slick had grown considerably when this photo was taken ten days later. The expanding environmental destruction will be worse than the 1989 Exxon Valdez disaster, when an oil tanker spilled 11 million gallons off Alaska’s shores.
While taking full responsibility for the cleanup and environmental repair necessitated by the spill spread from Mississippi Canyon 252, BP in latest interviews implied that responsibility for the accident itself rests with Transocean, the deep ocean drilling experts who operated the Deepwater Horizon oil rig. As of March 2, 2010, US$2.5 billion has been lost by the Louisiana shellfish and fin fish industries, and the tourist industry has taken a US$3 billion hit. President Obama has put a full stop on all offshore drilling until this event is fully understood, and new and better safeguards are implemented in similar deep ocean drilling situations.
Given the scale of the Deepwater Horizon rig blowout and fire, there are few comparisons available. The West Atlas deep sea oil rig operated by PTTEP Australasia blew out and caught on fire, September 2009 in the Timor Sea. It had defied all attempts to plug it as of November, 2009. By that time, 400,000 liters of oil, gas and condensate had leaked into the Timor Sea at a rate of 300 to 1200 barrels per day. The area covered is at least 100 times that of Sydney Harbor (6,000 km2).
No effective means to contain the Deepwater Horizon oil slick in the Gulf of Mexico has yet been found. High winds have blown through this portion of the Gulf of Mexico on many days since the spill. Several foot high waves take apart the barriers built from inflatable booms. Likewise in a high wind environment burning is not an option, nor are skimmers that suck oil from the surface effective. Other chemicals that break up oil before it reaches the surface are being applied at heretofore untested depths. These winds will also drive oil slick into inlets and creeks when it reaches the coastline. If the winds do decrease after May 2, then some of these containment methods will begin to have effect. Nonetheless, the loss of wildlife, endangered species and otherwise, commercial fishing stocks etc, is incalculable and numbers in the millions of individual animals. This is the birthing season for ~5,000 dolphins that frequent this region of the Gulf of Mexico. For dozens of affected species that are rare and officially endangered, this area is one of their last possible breeding habitats.
Last Hours of Deepwater Horizon on April 21, 2010.
By last Friday April 30, a sheen of oil from the edge of the slick washed up at Venice, La and other points in SE Louisiana. Several miles out, the blue-green gulf waters were dotted with pea to quarter size, sticky brown beads of oil condensate with the consistency of tar. This mess could reach three more states on Monday, May 3: Mississippi, Alabama and Florida. Louisiana tried an experiment by opening up the Mississippi levees to release a rush of fresh water into the gulf coastline waters. This attempt to drive oil away from the coast failed because of the high winds.
How Bad is Beyond Awful?
1900+ people, 300+ vessels and dozens of airplanes are deployed to fight this giant, monster oil slick. Two USAF C-130 Hercules cargo planes are dropping tens of thousands of gallons of oil dispersing chemicals into the slick. As Monday May 3 dawns in the Gulf of Mexico, winds appear to be breaking up the slick that extended east from Mobile Bay toward Pensacola. Oil remains emulsified but some beaches will not be dealing with tar. However, these same strong winds broke up 80% of the boom that was deployed before Sunday, May 3 and made skimming oil off the ocean surface impossible.