Temporary Cap for a Blownout Subsea Wellhead

Abstract

A device for collecting and confining oil escaping from a sea bottom wellhead blowout. The device is easily and quickly moved into position to contain the oil from a subsea well blowout. The device provides an improved method for recovering the oil flowing from a subsea well blowout and preventing the mixing of such fluids with large quantities of the seawater. An improved method of oil containment includes the positioning of a vertical capsule over a subsea well blowout and the conducting of oil through a conduit to surface processing and storage equipment. In addition, an improved method includes the formation of a seal completely around the blownout wellhead.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. Provisional Patent Application No. 61/709,132 filed on Oct. 2, 2012 by the present inventor, the contents of which are incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device and a means for collecting and confining oil escaping from a sea bottom wellhead blowout.

2. Background of the Invention

Subsea wells have the wellhead and pressure control equipment located on the seabed. Typically subsea wells may vary from depths of 10 feet to 8,000 feet. It is very difficult to deal with a blowout in very deep water because of the remoteness and limited experience with this type of situation. The Deepwater Horizon well blowout in the Gulf of Mexico in April 2010, in about 5,000 feet water depth, is the deepest subsea well blowout to date.

Blowouts from subsea wells usually contain oil, gas, and water. Upon reaching the surface the gas either burns or escapes to the atmosphere. However, even if there is a surface fire, most of the oil remains unburned and causes marine pollution. Several technologies have been developed for dealing with the surface oil to try to minimize pollution, with varying degrees of success.

While many of the techniques used in on shore operations to fight blowouts can also be applied in the offshore environment, they often prove to be less effective and require a much longer time period for implementation. Thus, for example, while relief wells can be drilled to intercept the blowout well, a great amount of time may be required in the drilling operation. In drilling the relief wells, platforms or other drilling support decks must be located and transported to the blowout site before drilling operations can be begun. Due to the rugged offshore environment, more time is required to drill the relief wells than would be required in an onshore operation. As a result of all of these difficulties, many months can pass between the occurrence of an offshore oil well blowout and the successful final capping of the blown out well. In the intervening time, large quantities of oil and gas can escape into the ocean with serious environmental impact.

As can be seen by reference to the following U.S. Pat. Nos. 4,324,505; 4,456,071; 5,114,273; and 3,599,434, the prior art is replete with offshore oil containment devices. Some of these inventions teach oil recovery by placing heavy domes over the seep location and imbedding the lower edge or skirt of the dome in the sea floor sediments. The dome structures are generally not suitable for containment of wellhead blowouts where large quantities of gas and oil are erupting. The force of such blowouts would tend to lift most domes. The dome shape is also not effective in diverting high speed flow. Some inventions teach oil recovery by lowering an inverted funnel shaped device directly over the wellhead to capture the flowing oil. These structures are not effective because the wellhead is not completely sealed thereby allowing oil to pollute the surrounding sea water.

SUMMARY OF THE INVENTION

The present invention provides a device and a means for containing the flow of oil from a subsea oil well blowout. The device is easily and quickly moved into position to contain the oil from a subsea well blowout. The device provides an improved method for recovering the oil flowing from a subsea well blowout and preventing the mixing of such fluids with large quantities of the seawater. An improved method of oil containment includes the positioning of a vertical capsule over a subsea well blowout and the conducting of oil through a conduit to surface processing and storage equipment. In addition, an improved method includes the formation of a seal completely around the blownout wellhead.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings in which like reference numbers represent corresponding parts throughout:

FIG. 1 is an illustration of a subsea well blowout and recovery device according to the present invention in position above the blowout site;

FIG. 2 is an illustration of the recovery device after it has been moved into position over the subsea blowout to contain the flow of fluids from the wellhead;

FIG. 3 is a profile view of the recovery device according to the present invention;

FIG. 4 is a profile view of the recovery device according to the present invention illustrating the fireproof shield.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully hereinafter, in which preferred embodiments of the invention are shown. The temporary cap for a blownout subsea wellhead that forms the basis of the present invention is designated generally by the reference number 10. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, like numbers refer to like elements throughout. The scaling of some components on the drawings may be exaggerated for clarity.

With reference now to FIGS. 1, 2, 3, and 4 the device 10 according to the present invention and its placement over a blown out subsea wellhead is illustrated. In FIG. 1, a subsea wellhead 170 is illustrated erupting a flow of oil forming a flume 140. A barge 15 from which is suspended a vertical capsule shaped recovery member 25, vertical channels 80, suspension members 50, positioning members 90, control members 70, and actuator members 100. The recovery member 25 is preferably made of a somewhat flexible material in order to be inflated by water. The recovery member 25 is designed to collect the oil until the wellhead 170 can be permanently capped.

The recovery member 25 is preferably supported from barge 15 or other suitable structure such as an offshore drilling platform on the ends of suspension members 50 and positioning members 90. There are preferably four suspension members 50 and two positioning members 90. The four suspension members 50 in the form of cables are pivotally attached to the recovery member 25 which aid in raising and lowering the recovery member 25 into the sea 190. The positioning members 90 aid in positioning and guiding the recovery member 25 over the wellhead 170 on the ocean floor 180. The suspension members 50 are pivotally attached to the recovery member 25 at the weight line 105 and are equally spaced apart. There may be more or less suspension members 50 depending on the size and weight of the recovery member 25. The suspension members 50 and positioning members 90 are attached to the barge at their respective spool 20.

Also illustrated on barge 15 are oil collection devices 30, spools 20, and actuator members 40. The oil collection devices 30 may be connected to a tanker to collect and store the oil for further processing. After the barge 20 has been positioned near the wellhead 170 as illustrated in FIG. 1, the recovery operation may be commenced. The barge 15 is placed into the position illustrated in FIG. 2 with the recovery device 10 positioned directly over wellhead 170. The cylindrical shape of the recovery member 25 captures the flume 140 from the wellhead 170 and effectively directs it into the vertical channels 80 where the oil travels to the sea surface 190 an into oil collection devices 30 on barge 15.

It may be preferable to initially position the barge 15 over the wellhead 170 totally by remote control for obvious safety reasons. Television cameras may be suspended from barge 15 to observe the relative positioning of the recovery member 25 and wellhead 170, if desired. As the recovery member 25 is lowered below the sea surface 190, the pumps on the barge 15 start immediately in order to suction air and water from inside the recovery member 25 to the sea surface 190. Water entering the recovery member 25 is pumped out and up to the oil collection device 30 by means of a pump located on the barge 15. By removing the air and water in this manner, the recovery member 25 will lose its buoyancy and sink. The suctioning action aids in lowering the recovery member 25 towards the ocean floor 180 to encompass the wellhead 170. Also, the suctioning action enhances stability of the recovery member 25 by reducing the effect of the high pressure oil flume 140 flowing into the recovery member 25.

A closing member 115 is provided at the lower portion of the recovery member 25. The closing member 115 is in the form of a drawstring 160 and seam 120 in the recovery member 25. Typically, the drawstring 160 is loose when not being used, and tightened when needed during use. The drawstring 160 is operatively connected to the recovery member 25 by being threaded through the seam 120. On the other end, the drawstring 160 is operatively attached to an electric motorized winch 150 which pulls the drawstring to close the opening 118 of the recovery member 25. The winch 150 is energized by either a backup battery pack 130 which is attached to the recovery member 25 or from a power supply 40 on the surface. An electric cable or actuator member 100 connects the motorized winch 150 to the power supply 40 on the barge 15 for provided power to the motor and also motor control.

As shown in FIG. 4, the closing member 115 may be surrounded with fireproof shields 210 to withstand the heat and pressure. The shields are connected together with connector members 230.

The drawstring 160 can be pulled to contract the opening 118 in the closing member 115 of the recovery member 25 in a manner such that the seam 120 of the recovery member 25 is drawn towards a central point, thereby clamping the closing member 115 around the wellhead 170 and forming a seal to contain the oil flume 140 in the recovery member 25 and preventing the oil from polluting the water.

The dimensions of the recovery member 25 and vertical channels 80 will, of course, vary according to the flow rate from the wellhead 170 and the water depth. The length of the channels 80 will be selected to accommodate the distance of the recovery member 25 over the top of the wellhead 170. The diameter of the channels 80 will depend upon the quantity of fluids to be contained. The recovery member 25 typically has a diameter of approximately 100 feet and is 250 feet in length from its open end 118 to the point of connection to vertical channels 80. While as noted above, the length of vertical channels 80 must be selected for a particular water depth, it can be seen that it is a simple matter to fabricate vertical channels 80 from standard steel tubing to any desired length. Shutoff valves 85 are provided near the top end of the recovery member 25 to stop the flow of oil from the recovery member 25 to the oil collection device 30 on the barge 15. The shutoff valves 85 are attached between the vertical channels 80 and the recovery member 25. Control members 70 run parallel to the vertical members 80 and function to provide a signal to open or close the shutoff valve 85 from the barge 15.

A weight line 117 is near the closing end 115 of the recovery member 25. The weight line 117 extends completely around the circumference forming a ring of weights around the recovery member 25. Typically, the weight line 117 consists of six 1,000 pound weights 110 equally spaced around the circumference of the recovery member 25 and equally spaced apart. The recovery member 25 is attached to the weight line 117 along with the suspension members 50 and positioning members 90.

The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims.

Claims

1. A device for collecting and confining oil escaping from a sea bottom wellhead blowout, comprising:

a vertical cylindrical capsule shaped recovery member constructed of a somewhat flexible material;

a plurality of suspension members and positioning members attached to said recovery member;

a plurality of control members and actuator members attached to said recovery member;

a weight line attached around the circumference of said recovery member; and

a closing member and an opening at the lower end of said recovery member.

2. The device of claim 1 wherein said suspension members and positioning members are attached to a barge on one end and said recovery member on the other end.

3. The device of claim 1 wherein said control members and actuator members are attached to a barge on one end and said recovery member on the other end.

4. The device of claim 1 wherein said weight line is attached to said positioning members.

5. The device of claim 1 wherein said closing member is attached to a battery pack.

6. The device of claim 1 wherein said closing member is covered with fireproof shields.

7. The device of claim 1 wherein said closing member is provided with a seam.

8. The device of claim 7 wherein said seam is threaded with a drawstring.

9. A method for collecting and confining oil escaping from a sea bottom wellhead blowout, comprising:

positioning the recovery member over the wellhead;

lowering said recovery member below the sea surface to encompass said wellhead;

pumping air and water from inside said recovery member to the sea surface;

pulling the drawstring to close said recovery member around said wellhead; and

pumping the oil contents of said wellhead to the oil collection device at the sea surface.

10. A device for collecting and confining oil escaping from a sea bottom wellhead blowout, comprising:

a vertical cylindrical capsule shaped recovery member constructed of a somewhat flexible material;

a plurality of suspension members and positioning members attached to said recovery member;

a plurality of control members and actuator members attached to said recovery member;

a weight line attached around the circumference of said recovery member;

a closing member and an opening at the lower end of said recovery member;

a battery pack attached to said closing member;

an electric motorized winch attached to said battery pack;

a seam on the circumference of said opening;

a drawstring threaded through said seam and attached to said wench.