US20120006559A1

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Info

Publication number: US20120006559A1
Application number: US12/906,874
Authority: US
Inventors: Alan D. Brite
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-07-09
Filing date: 2010-10-18
Publication date: 2012-01-12

Abstract

An oil well sealing device that is submergible for sealing under water oil wells and a method for sealing underwater oil wells in such a fashion that oil production can be resumed are described. The device comprises a housing having at least one lower opening at a lower end of the housing and at least one upper opening at an upper end of the housing; a pump sucking oil through the lower opening into the housing and pushing the oil through the upper opening out of the housing; a connector allowing the lower end of the housing to be fixed to an oil well tube at an oil wellhead; and at least one valve at the lower end of the housing that is closable after the lower end of the housing has been installed to the oil well tube.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-part patent application claiming the benefit of the U.S. non-provisional patent application Ser. No. 12/833,883 filed on Jul. 9, 2010. This prior non-provisional patent application Ser. No. 12/833,883 is herewith incorporated in its entirety by reference.

BACKGROUND OF THE INVENTION

For sealing underwater oil wells, two major problems need to be overcome:

- First, the immense pressure of the oil flow coming out of the open oil well pushes all elements that are attempted to be pushed into the oil well for sealing it away. This results particularly from the high oil pressure in combination with a relatively large diameter, for instance an oil well tube having an inner diameter of 20 in.
- Second, since the oil well is located deep below the water surface, the oil well is difficult to access due to both the distance from which any sealing equipment has to be operated, as well as due to the high water pressure requiring special equipment. This second part of the sealing problem makes it in particular difficult to apply the forces needed to counter the high pressure oil flow to apply a sealing element to the oil well.

In the prior art, so-called blow-off protectors have been used which are typically battery operated and pinch the entire oil well tube in case of an emergency such that the tube permanently deformed until the entire oil well tube is closed and the oil spill stopped. These blow-off protectors are designed to prevent oil spills in case of an emergency. A major disadvantage of these blow-off protectors is that these destroy the well tube and therefore shut down oil production in the worst case permanently. Particularly if the well is deep under the ocean surface, the oil well is permanently destroyed, or it is at least very costly to restore the oil well tube and resume production and this process takes a significant amount of time. Since good oil wells produce significant value, e.g. 3 Mio US$ daily, it is desirable to resume production, preferably as soon as possible.

It is an object of the invention to create an oil well sealing device that is capable of sealing underwater oil wells in such a fashion that oil production can be restored within a short period of time and at reasonable costs.

SUMMARY OF THE INVENTION

This object is achieved by an oil well sealing device that is submergible for sealing under water oil wells, comprising: a housing having at least one lower opening at a lower end of the housing and at least one upper opening at an upper end of the housing; a pump sucking oil through the lower opening into the housing and pushing the oil through the upper opening out of the housing; a connector allowing the lower end of the housing to be fixed to an oil well tube at an oil wellhead; and at least one valve at the lower end of the housing that is closable after the lower end of the housing has been installed to the oil well tube.

This object is further achieved by a method for installing a submergible oil well sealing device and resuming oil production, comprising: sucking oil from an underwater oil well at a lower end of the oil well sealing device into said device; pushing the sucked-in oil at an upper end of the device through at least one opening out of said device; installing the lower end of the device to the oil well; closing a valve at the lower end of the device; separating a lower end part of a housing of the oil well comprising the valve from the remaining upper part of the oil well sealing device; installing an oil pipe to an upper end of the lower part of the oil well sealing device; and opening the valve for resuming oil production.

DETAILED DESCRIPTION OF THE INVENTION

This apparatus and method according to the invention achieve that the oil well sealing device either lowers the counterforce by actually pumping away the oil at about the same speed as it comes out of the oil well, or even better, depending on the power of the pump, might suck additionally surrounding water into the device. Putting the effect in simple words, the device sucks itself into place and therefore overcomes the need of equipment pushing a sealing device into the well that is very difficult to operate that deep down below the water surface.

According to a preferred embodiment, the sucked in oil and possibly additional water may be guided out of the sealing device in a vertical direction upwards, providing additional thrust pushing the sealing device down into the oil well.

According to a preferred embodiment of the invention, the at least one valve is a mechanical valve that is operated remotely.

According to another preferred embodiment of the invention, the mechanical valve is adapted to be operated by a remotely operated underwater vehicle.

According to another preferred embodiment of the invention, the mechanical valve is connected to an electric motor in a torque transmitting manner and the electric motor is powered by an electric power cable supplying electric power from a location above the water surface.

According to another preferred embodiment of the invention, the oil valve is a hydraulic valve comprising a hydraulic piston and the pressurized hydraulic oil is provided through a hose from above the water surface.

According to another preferred embodiment of the invention, at least two valves are provided at the lower end of the housing; at least one of these two valves is a mechanical valve; and at least another one of these two valves is a hydraulic valve.

According to a preferred embodiment the housing comprises an elongated tube, the lower opening is the entire open cross section of the tube, and the upper opening is a radial opening in the tube. This achieves the maximum intake by avoiding any obstructing of the lower opening of the device. However, as an alternative, also a different shape or partial opening of the lower cross-section is possible, for instance by closing lower opening by a grid. Further, the upper openings do not need to be just radial openings, but could deflect the flow such that it exits the device in the vertical direction upwards, generating additional thrust pushing the entire device in direction of the oil well.

According to another preferred embodiment the pump comprises an auger that rotates within the tubular housing. In the alternative, the pump could actually be of any form or shape. An auger has the advantage of a relatively simple design and can be rotated at relatively high speed, therefore conveying a high oil flow as needed for lowering the pressure from the oil flow enough for pushing the sealing device into the oil well.

According to another preferred embodiment the auger is rotated by a motor that has a reversible rotational direction. Any kind of motor that can be encapsulated in a water tight fashion and therefore operated under water is suitable. Strong electric motors are available both for industrial purposes and for powering automobiles. However, it is also possible to use hydraulic motors that can be fed by hydraulic lines and provide the advantage of high power output at relatively small space. Both electric motors and hydraulic motors can be easily reversed in their rotational direction.

According to another preferred embodiment the lower end of the device is adapted to be connected to a spigot joint that is attachable in a sealed fashion to the oil well. The spigot joint may preferably have a spigot sleeve that can be pre-attached to the tubular housing and protrude therefrom by such a length as it is desired to be inserted into the oil well tube. For sealing the protruding portion in relation to the oil well tube, the protruding portion may carry O-rings on its circumference that engage the inner wall of the oil well tube when inserted therein. Again, O-rings provide the advantage of a self-sealing effected under pressure so that the oil pressure actually helps to accomplish a sealing action.

According to another preferred embodiment the valve is opened and closed by applying torque to the valve by a remotely operated underwater vehicle.

According to another preferred embodiment the valve is opened and closed by applying torque to the valve by an electric motor that is powered by an electric power cable supplying electric power from a location above the water surface.

According to another preferred embodiment the valve is opened and closed by applying hydraulic pressure to a hydraulic piston through a hose from above the water surface.

According to another preferred embodiment opening and closing at least two valves at the lower end of the housing is performed, wherein at least one of these two valves is a mechanical valve and subjected to torque by a remotely operated underwater vehicle; and at least another one of these two valves is a hydraulic valve and subjected to hydraulic pressure through a hose from above the water surface.

According to another preferred embodiment of the method according to the present invention an auger is provided as a pump, said auger rotating within the housing that is shaped as a tube and rotating the auger first into a first direction during installation of the oil well sealing device and then into a second direction after the lower end of the device has been installed to the oil well. An auger is a relatively simple and effective pump and can be rotated at relatively high speed, for instance 2000 to 3000 rpm. However, any other type of pumps can be used such as piston pumps or rotary vane pumps.

According to another preferred embodiment of the method according to the present invention a hollow spigot sleeve is installed to the lower end of the device and then the spigot sleeve is pushed in a sealing fashion into the oil well. However, it is also possible to reverse the sequence of installation steps according to another preferred embodiment, namely by installing a hollow spigot sleeve to the oil well and then installing the lower end of the device to the spigot sleeve. The latter installation sequence might be a little more cumbersome since it requires the extra step of attaching the spigot sleeve first to the oil well tube, but should also be possible since the spigot sleeve is hollow and therefore free from being subjected to a high force rejecting the spigot sleeve by the oil flow from the oil well.

The invention is described in more detail in the following by referring to the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic side sectional view of an embodiment of the oil well sealing device according to the present invention as described in the parent U.S. non-provisional application Ser. No. 12/833,883.

FIG. 2 shows a schematic side sectional view of a second embodiment comprising a hydraulic valve and a mechanical valve at a lower part of the oil well sealing device.

DETAILED DESCRIPTION OF THE DRAWINGS

TheFIG. 1 shows a schematic side view of the submerged oilwell sealing device1 for sealing underwater oil wells. The device comprises anupper end2 and alower end3 and extends during use substantially in vertical direction. The device comprises the shape of an elongated tube, particularly sized for having a diameter of a typicaloil well tube5, for instance a diameter of 20 in or larger, depending on the size of the oil well. The entire device is forinstance 18 ft. long. Aspigot sleeve6 is either pre-installed into thehousing4, for instance by a press fitting or welded to thehousing4, or it is pre-installed into theoil well tube5 so that the spigot sleeve protrudes theoil well tube5 by a certain distance. This protruding part has an outer diameter that is a little smaller than the inner diameter of the tube-shapedhousing4. In any of the two aforementioned alternatives, the spigot sleeve is designed to center thehousing4 and connect it with of theoil well tube5. O-rings19 can optionally be provided, sealing thespigot sleeve6 with respect to theoil well tube5, or optionally also with respect to the tube-shapedhousing4.

The oilwell sealing device1 comprises further aclosing element7 that is shaped according to this embodiment as a cylinder, comprises severalupper openings8, in this case eightupper openings8 spaced apart around the circumference of the tube-shapedhousing4 at theupper end2 of the device, and alower opening9 that is simply according to this embodiment the lower open cross-section of the tube-shaped housing.

Anauger10 is provided within the tube-shapedhousing4, and is driven via ashaft11 that is rotated by anelectric motor12. Twohydraulic cylinders13 are provided for moving theclosing element7 along the tube-shapedhousing4, particularly into a closing position where theupper openings8 are closed, i.e. substantially to prevent that oil coming from the oil well can escape the sealing device once it has been installed and is moved into its closed position. Theclosing element7 also prevents water from the outside to penetrate through theupper openings8 into the sealing device. When theclosing element7 has been moved into its closing position, one or more biased locking pins14 may snap into place, locking the closing element into its closing position. These locking pins14 may for instance snap into holes or recesses15 that are formed in the wall of the tube-shapedhousing4.

Theclosing element7 may carry two sets of O-rings, namely a first set of O-rings16 and a second set of O-rings17. These two sets of O-

rings

16 and17 are spaced apart by a distance that is larger than the longitudinal size of theopenings8 measured in the longitudinal direction of the tube-shapedhousing4. In the locked position of theclosing element7, the first set of O-rings16 is vertically above theupper openings8, and the second set of O-rings17 is in vertical direction in the locked position of theclosing element7 below theupper openings8.

In the following, the process of installing the oil well sealing device and finally sealing the oil well are described.

The oil well sealing device is used as a stand-by device in case an underwater oil well gets out of control as far as the ability to seal the oil well is concerned. The main problem of sealing an oil well is the extreme pressure under which oil comes out of the oil well, creating a fast flow of pressurized oil. This powerful oil flow prevents installing any plugs sealing the well. The embodiment of the invention as described above targets this problem by actively pumping the oil off so that the pressure pushing any sealing plug into the oil well is reduced to a minimum that can be overcome by force or gravity, or in the ideal situation, even provides a positive attractive force sucking the entire oil well sealing device into place.

Thedevice1 is lowered to be basically aligned with the oil well at such a distance that the oil flow coming out of theoil well tube5 allows without any further action. Then, theelectric motor12 is started. As an electric motor, for instance a motor of an electric car can be used that is capable of providing rotational speeds of over 2000 rpm. Via ashaft11, theauger10 is rotated, sucking in water and some oil through alower opening9. If thespigot sleeve6 is pre-attached to the tube-shapedhousing4, the mixture of water and oil is sucked in through thelower opening18 of thespigot sleeve6. The mixture of oil and water sucked into the tube-shaped housing by the auger can leave thehousing4 radially through theupper openings8. In another preferred embodiment, outlet tubes can be attached to theradial openings8, deflecting the radial liquid stream upwards in axial direction of the tube-shaped housing, creating additional push in the direction of the oil well. Instead of radial upper openings, it is also possible to guide the flow through the tube-shapedhousing4 to the very upper end and exhaust this flow in a vertical direction upwards, creating extra thrust and therefore push on theentire device1 downwards. In this case, theelectric motor12 needs to be either installed laterally, or tubes can guide the flow around theelectric motor12.

The sucking action allows lowering theentire device1 even further, until thepre-attached spigot sleeve6 can enter into theoil well tube5. The tube-shapedhousing4 can then be anchored to theoil well tube5 in a conventional manner, for instance by anchors or other fastening devices. Also, thespigot sleeve6 may be pressed-fit into theoil well5. Also, locking pins or locking screws are an option.

After the tube-shapedhousing4 has been fixed to theoil well tube5, the auger still rotates initially in the same direction, now only pumping oil and no water from the oil well out through theupper openings8. Since the ultimate goal is to seal the oil well, now theupper openings8 need to be closed. For this purpose, theclosing element7 is pushed down via thehydraulic cylinders13 so that the second set of O-rings17 rests below theopenings6 while the first set of O-rings still remains above theopenings8. In other words, theopenings8 are sandwiched between the two sets of O-

rings

16 and17 in the closing position of theclosing element7. When theclosing element7 has reached its closing position, it can be locked with respect to the tube-shapedhousing4, for instance by lockingpins14 snapping into respective recesses or holes15 provided in the wall of the tube-shapedhousing4. Theclosing element7 may likewise be locked by other means into its closing position, for instance by locking pins inserted from the outside of thehousing4, or any other type of latch that may for instance engage the plane top face of the cylinder-shapedclosing element7.

In order to facilitate the movement of theclosing element7 into its closing position, the rotational direction of the auger can be reversed prior to or during movement of the closing element. This reverses the pumping direction, namely now with the reversed rotational direction no oil is pumped out of the oil well, but to the contrary, water is pumped from theopenings8 into the oil well if the pumping pressure and respectively theelectric motor12 are strong enough for reversing entirely the direction of flow. However, even if the power of theelectric motor12 and respectively the rotational speed of the auger are not sufficient for entirely reversing the direction of flow, at least the pressure from the oil acting upon the lower front face of the closing element is reduced, allowing theclosing element7 to be pushed downwards with less force by thehydraulic cylinders13.

With theclosing element7 locked in its closing position and the tube-shapedhousing4 being attached to theoil well tube5, the oil well is now sealed and theelectric motor12 can be turned off.

Another embodiment is shown inFIG. 2. The same reference numerals that are in common withFIG. 1 are also used in the embodiment shown inFIG. 2. This embodiment shown inFIG. 2 distinguishes from the embodiment shown inFIG. 1 by comprising at the lower end of the device a firsthydraulic valve20 and a secondmechanical valve21. Even though it is possible to provide only one of the

valves

20 and21, the redundancy in providing two valves that are preferably operated by different mechanisms enhances the safety against failure of one of the valves.

At the very lower end, thedevice1 is basically connected to theoil well tube5 as described inFIG. 1 with the additional feature of providing aflange37 at the lower end of the housing of the device that can be connected to a corresponding flange of theoil well tube5. In contrast to the embodiments shown inFIG. 1, the closing element7 (FIG. 1) is omitted, but instead the

lower valves

20 and21 have the function of shutting the oil flow down after the oilwell sealing device1 has been fixed to theoil well tube5. The entire oilwell sealing device1 can be separated into anupper device part22 comprising thehousing4 and theelectric motor12 and alower device part23 for separating the lower and

upper device parts

22,23 from each other. For instance as a separable connection, a connection via aflange24 is possible. Any type of standard, fluid tight connection between the upper and the

lower housing parts

22,23 would work for this purpose.

After having installed the oilwell sealing device1 to theoil well tube5, either the firsthydraulic valve20, or the secondmechanical valve21 can be closed, or both

valves

20 and21 can be closed. Preferably, it is first tried to close thehydraulic valve20. For this purpose, pressurized hydraulic fluid can be guided through aconduct25 into apiston chamber26, pressurizing apiston27 that is moved from its first position shown in interrupted lines into a second position shown in solid lines. While maintaining the hydraulic pressure in thepiston chamber26, theupper device part22 can be removed, for instance by unscrewingscrews28 that flange the upperpart device part22 to thelower device part23. Instead of maintaining the pressure in thepiston chamber26, it is also possible to lock thepiston27 mechanically in place so that it maintains its closing position shown in solid lines even if the pressure in thepiston chamber26 is released.

After the upper oil wellsealing device part22 has been removed and thehydraulic valve20 maintains its closing position, theupper device part22 can be substituted by an oil pipeline. After the oil pipeline has been fixed in a fluid tight manner to the lower oil wellsealing device part23, is possible to release the piston, for instance by pressurizing apiston chamber29 on the opposite side of thepiston27. After the piston has been moved back into its open position shown in interrupted lines, oil production is restored.

Thehydraulic valve20 has the advantage that hydraulic oil can be easily supplied from a location above the water surface so that no operation by external remotely controlled devices is necessary. Also, the hydraulic mechanism is relatively simple and therefore reliable. However, if thishydraulic valve20 turns out to fail due to unforeseen circumstances, it is preferable to provide redundancy by the second, mechanical valve that is operated by rotating aspindle31 moving avalve slider32 from an open position shown in interrupted lines into a closed position shown in solid lines. Thisspindle31 can be rotated by coupling any kind of torque transmitting element to it, for instance like in this embodiment coupling it aclaw33 rotated by an external remotely controlled underwater vehicle, for instance by coupling theclaw33 to ahexagon34 that is connected in a torque transmitting manner to thespindle31 or integrally formed therewith. In the alternative, thespindle31 can be rotated by anelectric motor35 receiving power through power lines36 that can be guided all the way to a location above the water surface. The electric motor can be connected to thelower part23 in the oilwell sealing device1.

Again, theupper part22 of the oilwell sealing device1 can be separated from thelower part23 and substituted by an oil pipeline, and after the substitution themechanical valve21 can be opened again by rotating thespindle31 into the opposite direction than the closing direction. This can again be accomplished by either theelectric motor35, for instance changing poles to reverse the rotational direction, or by the remotely controlled underwater vehicle. It is to be understood that the substitution of theupper part22 of the oilwell sealing device1 can be accomplished after thehydraulic valve20, or themechanical valve21, or both valves have been closed, and respectively oil production is restored after all valves that have been previously closed are opened again after installation of the oil pipeline.