White Paper: Closing of Underwater Oil Spills with Magnetic Material
Small magnets mixed with iron chunks inserted into an oil well stops the spill, much like plaque limits the passage of blood in arteries.
By Dr. Rainer B. Meinke, Ph.D., Chief Scientist • Advanced Magnet Lab, Inc.

The recent Deepwater Horizon underwater oil spill in the Gulf of Mexico has severe economic impacts for the Gulf coast States with thousands of jobs being lost and businesses wiped out. For the environment the spill constitutes an unprecedented disaster. Scientists fear that the volume of oil released into the ocean, the depth of the leak and the chemical dispersants that BP has used will combine to threaten a vast array of undersea life for many years. A similar disaster previously occurred in 1979 in the Gulf, when the Ixtoc-1 oil well got out of control, and more than nine months passed by, before the spill could be stopped. Given the large underwater oil reserves worldwide and the vast energy demand of our society, spills with devastating consequences are likely to occur again. To prevent this from happening, a technique is urgently needed that allows rapid closing of underwater oil wells that get out of control and can spill millions of gallons of crude oil into the ocean per day. The required technique has to be absolutely reliable, preferentially low tech with little possibility of failure. Any time that can be saved in closing a spilling well or achieving a significant reduction in the oil spill, reduces the economic and environmental impact of such disasters.

The Advanced Magnet Lab, Inc. (AML), a small, high tech business in Palm Bay, Fla., has developed a concept for stopping underwater oil spills with the help of magnetic materials as used in electrical motors and similar devices that are readily available. Due to the high field strength of modern magnetic materials, such as NdFeB (neodymium-iron-boron), Alnico and others, such permanent magnets form extremely tight bonds when coming in contact. The acting forces between such magnets, half an inch to one inch in diameter, can best be described as bone crushing. In large quantities permanent magnets mixed with chunks of iron form heavy, self-assembling “blankets” or “plugs”. The formed assemblies are flexible, automatically conform to the shape of surrounding steel, and strongly adhere to it. With a sufficient amount of such materials, the formed magnetic structures can withstand the large pressures acting in underwater oil wells.

Due to the high density of the materials, such permanent magnets mixed with iron particles of similar size can be poured into a spilling bore hole and under the influence of gravity, sink or attach themselves to the surrounding steel pipe against the high flow rate of the oil. The magnetic material accumulates, where it is discharged and will systematically reduce the amount of escaping oil. With a sufficient column of such material the oil spill is stopped or sufficiently reduced so that any remaining seepage of oil can be siphoned off with conventional means. A similar procedure can be used for reducing and stopping the flow of oil out of a pipe that is lying on the ocean floor like the broken riser pipe of Deepwater Horizon. In this case magnetic material can be simply dumped onto the opening of the pipe, forming a kind of magnetic blanket that significantly reduces the amount of oil escaping in the environment. The steel lining of a bore hole or a spilling pipe increases the robustness of the formed structure due to the strong attraction between the steel and the magnetic material.

The Proposed Technique
It has been unsuccessfully tried to stop the oil spill of Ixtoc-1 and Deepwater Horizon with the so-called “top kill” procedure. In the attempted process heavy drill mud is introduced under high pressure into the bore tube. However, the procedure failed, since the mud particles are flushed away by the oil stream given a realistic pressure that can be sustained by the bore hole without the danger of rupture and worsening the situation.

In contrast to the “top kill” procedure, heavy and relatively large particles with a strong tendency of sticking together are able to counteract the drag forces of the gushing oil under the sole influence of gravity. Small permanent magnets, mixed with small iron balls meet these requirements and therefore sink and accumulate when introduced into a vertical bore tube. AML has calculated that given an oil flow rate of 50,000 barrels per day out of a pipe of 20 inch diameter, the gravity force acting on particles with a half inch diameter is more than three times larger than the drag force caused by to the oil flow. Such magnetic material, preferentially with spherical shape, sustains the acting drag force of the spilling oil. The material can be inserted into the bore tube with the help of a non-magnetic aluminum or stainless steel pipe that protrudes deep enough into the opening of the spilling tube as schematically shown in Figure 1. When the flow rate has been sufficiently reduced, iron filings can be added, which also stick to the inserted magnetic material, and due to their small particle size further reduce the flow rate of oil by closing even the finest openings in the assembled magnetic plug.

Permanent magnets are produced from fine powders of different magnetic materials (e.g. neodymium-iron-boron (NdFeB) or Alnico, an alloy of aluminum, nickel and cobalt) that are sintered under high pressure and then magnetized. Such material is readily available in large quantities and small permanent magnets of different shapes and sizes are routinely produced. In most cases these magnets are coated for handling and environmental protection, which also makes them inert against sea water for a sufficient amount of time.

In order to insert the magnetic particles into a delivery pipe some handling device is required. Since the particles have a strong tendency of sticking together, a mechanism is needed at the inlet of the delivery pipe, which inserts the magnetic particles in appropriate chunk sizes that easily pass through the delivery pipe. The magnetic material could also be mixed with the standard mud used in drilling and inserted under pressure.

For spills of horizontal pipes, where gravity cannot be used, a containment or perimeter structure can be formed about the region from which a flow of oil emanates. The containment structure may be an iron ring, or a series of iron plates vertically positioned with respect to the ocean floor, to define a perimeter within which the magnetic material is placed. In this case, buckets filled with the magnetic material are lowered down to the ocean floor a few feet above the containment area. When the target position is reached, the bottom of the bucket is opened to dump the material into the containment ring. Due to the strong tendency of the magnetic material of sticking together the material forms a kind of blanket that significantly reduces the oil flow. Again after a sufficient flow reduction is achieved, iron filings or concrete can be used to decrease the remaining porosity of the cover. The procedure for different orientations of a ruptured pipe is schematically shown in Figure 2. As before the large density of the magnetic material and the acting forces acting within the material are the key property that prevents the cover from simply being washed away by the oil flow.

Will the Proposed Technique Work?
AML has performed laboratory tests that established the viability of the proposed procedure. In these tests a steel pipe of 3-inch diameter was connected to a water pump that generates a realistic water flow. The flow velocity of water was adjusted to represent a spill of 50,000 barrels per day escaping from a pipe of 20-inch diameter. Readily available permanent magnets with cylindrical shape and diameters of a quarter inch and half inch where dropped through a non-magnetic tube into the spilling water pipe. Iron balls of similar dimensions, as used in ball bearings, were mixed with the permanent magnets. Such iron balls are inexpensive and can be added to the permanent magnets in large quantities, with ratios of iron balls to permanent magnets of five to one or even larger, without significantly compromising the robustness of the forming plug. The iron balls are strongly attracted to the permanent magnets and channel the magnetic flux to attract other balls or magnets. The inserted magnetic material showed a strong tendency to stick to the steel of the water pipe in the vicinity where it is released from the inserted non-magnetic delivery tube. It is therefore necessary to move the delivery tube upwards as the build-up of the magnetic plug progresses.

In the simple laboratory test a plug of permanent magnets and steel balls with a total length of about 25 inches was assembled as described. During the assembly of the magnetic plug the remaining volumetric flow rate of the water was recorded by simply measuring the amount of water escaping in a given interval of time. As shown in Figure 3, the measured residual water flow shows a linear decrease with the thickness of the magnetic plug inserted into the water pipe. With the length of 26.5 inches the flow rate of water was reduced by 75 percent. Given the linear decrease in water flow with the thickness of the plug an almost complete stop of flow is possible. For an underwater oil spill the generated plug could have a length of 20 feet or more, build up until the flow is sufficiently reduced.

At no time during the test, was the water pressure able to break particles loose from the plug or move the magnetic plug in the steel pipe. A photograph of the assembled plug is shown in Figure 4. The bonding between the plug and the surrounding steel pipe is so strong that the plug could not be removed after the test by pressing or hammering on it. The individual permanent magnets and iron balls have to be disassembled part by part to remove them from the steel pipe.

Summary
The proposed procedure of inserting a mix of strong permanent magnets and iron balls into the bore hole of a spilling underwater oil well constitutes a simple way of reducing the flow of the escaping crude oil in a highly controlled manner. The procedure is highly reliable and low tech with little possibility for failure. If a sufficient amount of magnetic material and the required delivery equipment is kept in storage, the procedure of stopping an oil spill can be started with very little delay of precious time. By acting expeditiously with proven technique the impact of a catastrophic oil spill like the Deepwater Horizon can then be significantly reduced. The Advanced Lab, Inc. has filed patent protection for the proposed process and is confident that the oil industry will adopt it to strongly mitigate the impacts of any future events.

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