Patent Publication Number: US-6666278-B2

Title: Oil well fire suppression device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to oil well fire suppression devices and more particularly to a portable, self contained fire suppression device serving the dual purposes of extinguishing an oil well fire and thereafter sealing the well against further leakage and re-ignition. 
     2. Background 
     In the recent Gulf war, Iraqi forces ignited over 600 oil wells in an effort to eliminate Kuwait&#39;s oil infrastructure. The conflagration lasted from February 1991 until Nov. 6, 1991. During this period it is estimated that the daily loss of oil and natural gas was between 4-6 million barrels and 100 million cubic meters respectively. 
     The two major problems encountered by firefighters in Kuwait were lack of equipment and lack of water. Cranes to lift the wellheads, backhoes to dig around the wellheads, dozers to build roads and move debris and equipment to fight the fires were in short supply and desperately needed for the firefighting to begin in earnest. Existing pipelines used to carry oil from gathering stations in the oilfields to the Persian Gulf were reversed to carry saltwater from the Gulf back to the oilfields to fight the fires. The logistical problems involved in pumping the 1.5 billion gallons of water that was eventually used to fight the fires slowed the flow of water to a trickle. 
     It was discovered that extinguishing the fire was not the most difficult part of well control. It&#39;s what is done after the fire is out that is dangerous. As long as the well is blowing, there is a possibility the well could flash and re-ignite, injuring or killing everyone on location. This dangerous potential is why one can&#39;t wait for water, or to borrow equipment from the next location. Everything has to be in place to cap the well once the fire is out. The less time spent capping the well after the fire is out, the less likely someone gets hurt. 
     Prior art methods for extinguishing well fires utilized vast quantities of water or explosive charges to snuff out the fire after which the well had to be approached for capping. Approaching the well was often complicated by the build-up of coke around the site which required excavation to be carried out in dangerous proximity to the gushing well. The risks are obvious. 
     The present invention is deployed using a large bulldozer such as a Caterpillar D11. The unit is attached to a hydraulically controlled frame mounted to the front of the bulldozer. The unit can be raised and lowered in order to position it over the well fire. 
     The unit operator is protected within a protective cab equipped with air conditioning, window cleaning systems, two-way radio communications, and an emergency escape plan/egress system. 
     SUMMARY OF THE INVENTION 
     In a preferred embodiment the present invention provides a portable, self contained containment device for extinguishing oil well fires. It is a primary objective of the device to be able to rapidly deploy to a well fire site and, with a minimum of logistical preparation consisting simply of filling tanks within the containment device, and positioning it over the fire. 
     It is a further object of the invention to construct the containment vessel in a manner which utilizes well known principles of science to physically contain and extinguish the fire within seconds, channel and control escaping oil and gas, and plug the well with a removable bladder. The bladder being capable of withstanding well head pressures up to 800 psi. such as those found in wells in the Middle East 
     It is a further object of the invention to use escaping oil to cool the containment vessel and well head environment. 
     It is a further object of the invention to use heat activated valves to release liquid nitrogen into the fire column to use the force of the fire to suck the nitrogen into the flame thereby assisting to extinguish it. 
     In Operation 
     It is a further object of the invention to follow a sequence of deployment as follows; 
     1. Fill a water containment cylinder 
     2. Fill Nitrogen tanks 
     3. Open oil and gas escapement valves 
     4. Add sand to the leveling box to equalize weight 
     5. Approach vessel with lifting equipment 
     6. Raise containment vessel to 12″ above well head keeping the bottom of the vessel below the flames. 
     7. (If necessary) Proceed to the well at the direction of two spotters 
     8. Lowering the vessel in place once it is over the well casing. (It need not be perfectly centered) 
     9. Using the deployment vehicle as additional ballast to keep the vessel in place adds a further 203,000 pounds to the initial weight of the vessel (38,000 pounds.) 
     It is a further object of the invention to follow the above deployment sequence to initialize the extinguishment/containment sequence; 
     1. Cessation of oxygen to the flame 
     2. Heat activated nozzles release nitrogen 
     3. Perforated internal baffles break oil down 
     4. Flame is extinguished in 5-8 seconds 
     5. Vessel begins to fill with oil aiding cooling of the vessel 
     6. Gas release valve is slowly closed forcing remaining energy and flow of oil through the oil release valve 
     7. Once oil temperature is reduced sufficiently, oil release valves are slowly closed. Oil is now contained. 
     8. Expandable bladder is inserted into the well casing to restrict the flow of oil and gas. 
     9. With the bladder in place approximately 10′ to 20′ into the casing, the top of the bladder shaft can be removed, the oil drained from the vessel which can then be removed. 
     10. A “Christmas tree” manifold is fitted to the well casing providing a second valve containment means 
     11. Pressure is released from the bladder which is then raised above the level of the Christmas tree valve. Once it is above the level of the lower valve, it can be closed to complete the containment process. 
     Vessel Deployment 
     Utilizing a vehicle such as a Caterpillar D11, a continuous lifting beam is attached to each side. The lifting beam extends 30′ from the center pin to the front or lifting section. The beam extends 24′ to the rear of the center pin. Attached to the rear section are a pair of hydraulic cylinders. As the vessel approaches the well, the operator places the containment vessel in place as described. The rear cylinders are then activated and pressed into the ground lifting the bulldozer off the ground thus transferring its weight to the base of the containment vessel. 
     General Specifications 
     The following are the general specifications for a first embodiment of the invention; 
     1. (FIG. 1-12) Water containment Cylinder ( 1 ) 10′ diameter, 10′1″ high with a wall thickness of ½″ steel. Approximate weight 6,444 lbs. Purpose: to provide ballast, will contain approximately 13,000 lbs of water which will also serve as coolant. 
     2. (FIG. 1-21) Oil containment Vessel ( 1 ) 15′ high, 5′ diameter, wall thickness 1″ steel, approximate weight 9,525 lbs. Purpose: When placed over the well, it will penetrate the sand, sealing off the oxygen from the bottom. It will then fill with oil becoming as temporary of permanent containment vessel. 
     3. (FIG.  1 - 22 , 22 ′) Steam relief vents ( 2 ) Size—6″ pipe 5′ long. Will release steam from the water containment cylinder. 
     4. (FIG. 1-41) Primary baffle ( 1 ) Size, 5′ diameter cone with flat top plate that has 36 2″ holes. Thickness—1″ plate. Purpose: To reduce the oil from one solid cylinder (column) to 32 individual cylinders thus reducing pressure. 
     5. (FIG. 1-42) Secondary Baffle ( 1 ). Size 5′ diameter 30 degree cone. Thickness ½″ plate with 1″ holes. Purpose: The further reduce oil particle size and thus oil pressure. 
     6. (FIG. 1-43) Third baffle ( 1 ) Size 5′ diameter 15 degree cone. Thickness, ½″ plate with ¾″ holes. Purpose: Same as second baffle. 
     7. (FIG. 1-21 a ) Fourth baffle ( 1 ) 5′ diameter plate. Thickness ½″ plate with ½″ holes. Purpose: Same as other baffles. 
     8. (FIG. 1-18 a ) Drain for water containment cylinder ( 4 ) Size, 4″ pipe with ball valve. Purpose: To drain hot water from the cylinder to allow for cool water to be pumped in. 
     9. (FIG. 1-24) Gate Valve ( 1 ) Size—12″. Purpose: To control energy being released from fire and well head. 
     10. (FIG. 1-18 a ) Horizontal relief and control pipe. Size—8″ pipe. Purpose: Primary purpose is to release pressure in the vessel, the secondary purpose is to control the flow of oil. 
     11. (FIG. 1-19 one only shown) Gate valves ( 2 ) Size—8″. Purpose: To control the flow of oil. 
     12. (FIG. 1-18 b ) Check valve ( 1 ) Size—8″. Purpose: To prevent the flow of oxygen to the vessel. Will also allow for the flow of oil when required to so do. 
     13. (FIG. 1 22 , 22 ′) Water Pipe Connection ( 4 ) Size—4″ pipe with quick connects. Purpose: To allow the flow of water into the water containment cylinder. 
     14. (FIG.  1 - 50 , 50 ′) Liquid Nitrogen Cylinder ( 4 ) Size 10″-48″. Purpose: To immediately cool the oil vessel while simultaneously extinguishing the fire. 
     15. (FIG. 1-50 a ,  50   a ′) Insulation packs ( 4 ) Size—4″ mineral wool batt with protective covering. Purpose: To prevent overheating of the nitrogen tanks. 
     16. (FIG. 1 21   c ) Spray foam insulation. Thickness—1½″. Purpose: To protect the oil vessel wall during flame suppression. Possible products—Fendolite M-11, Albi clad #800, Pyrocrete 241 or Kaowal Firemaster board. 
     17. (FIG. 1 16 ) Ballast Box. ( 1 ) Size 2′×10′×3″. Wall thickness—½″ steel. Purpose: To equalize weight and balance the unit. Can be filled with sand as required. 
     18. (FIG. 1 51 , 52 ) Nitrogen Piping and Heat controlled nozzles. ( 4 ) Size—4″ pipe. Purpose: To transfer Nitrogen from the tank to the vessel, with the nozzles releasing nitrogen at a specified temperature. 
     20. Ladder for maintenance purposes. 
     21. (FIG. 3 30 ) Motor unit to lower the shaft and bladder into the well casing. 
     22. (FIG. 3 92 ,  47 ) Shaft and bladder. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG.  1 . is an isometric view partially in section of the oil well fire containment unit. 
     FIG.  2 . is a diagrammatic illustration of the oil well fire containment unit as it operates. 
     FIG. 3 is an elevational view partially in section of the oil well sealing unit. 
     FIG. 4 is an elevational view of the deployment means for the oil well fire containment unit. 
     FIGS. 5-8 are plan views of the baffles showing their differing screen sizes. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings wherein like numerals designate like and corresponding parts throughout the several views, in FIG. 1 the unit is designated overall by the numeral  10 . water containment vessel  12  is filled through fill pipes  22  and  22 ′. Ballast box  16  can be filled with sand. Oil containment vessel  21  encases baffles  41 , 41   a ,  42  and  43 . Well head  40  is covered by oil containment vessel  21 . Oil gushing from well head opening  48  is forced up toward lower baffle  41   a  then to baffles  41 ,  42  and on up to baffle  43 . Holes  43   a  (shown only in baffle  43 ) permit oil to fill container  21 . As oil enters container  21 , heat activates nitrogen release valves  52   b  and  52   c  and nitrogen is released from tanks  50  and  50 ′ down pipes  51  and  52 . Gas is released through vent pipe  20  through control valves  24  and  26 . Valve  24  is controlled by wheel  24   a  which can be turned using chain  24   b . Oil can be released through pipe  18  controlled by valve  19 . Oil containment vessel  21  can be drained through outlet pipe  18   a . Center pipe  46  houses the shaft  92  (FIG. 3) which moves bladder  47  down into well head  40 . Motor controls for shaft  92  are contained in motor unit  30 . Lights  60  illuminate the scene for night operation. 
     Referring now to FIG.  2 . burning oil and gas  82  go up through oil containment vessel  21 . Gas  84  vents through pipe  20  and oil  83  vents through pipe  18 . Nitrogen vents through pipes  51  and  52  in the direction of arrow  80 . Bladder  47  is lowered into well head  40  through opening  48 . 
     Referring now to FIG. 3 in which motor unit  30  is illustrated. Screw thread  91  connected to shaft  92  is turned by gear  97  and  97   a  driven by motor  98 . Thrust bearings  95  and  96  in housing  94  in casing  93  allow shaft  92  to rotate while under pressure. Mounting bracket  99  keeps the rotating components from binding while the unit is operating. Bladder  47  is lowered into well head  40  as shaft  92  is screwed downward. 
     Referring now to deployment of the unit as illustrated in FIG.  4 . Bulldozer  110  is fitted with cab  105 , rams  101  and  104 , and lift unit  100 . Fire suppression unit  10  is supported by front mount  103  of lift unit  100  and positioned over well head  40  as bulldozer  110  moves in the direction of arrow  108 . Once in position, ram  101  presses foot pad  106  down in the direction of arrow  107 . This causes bulldozer  110  to lift at the rear and by pivoting around pivot point  102 , transfers its weight to the containment unit  10  thereby increasing its stability over the well head  40 . Bracket  12 ′ denotes scope of travel of fire suppression unit  10 .