Systems and Methods for Catastrophe Mitigation for Deep Water Oil Drilling during Blowout Preventer Failure
Disclosed herein in example embodiments is a simple Drill-Through-Equipment (DTE) system for deep water drilling of oil, to intervene in the event of Blowout Preventer (BOP) failure, and mitigate spill disaster. Example embodiments of systems and methods of failed BOP intervention, and oil spill disaster mitigation disclosed herein may be used to mount a housing within the existing BOP below the blind shear ram, whereby the failed BOP is made accessible just below the blind shear ram through access ports, opening or closing in the housing. Through these ports blowout is diverted, thus protecting the rig. Through these same ports access is granted to the drill pipe allowing external manipulation or cutting of the drill pipe in effort to render the BOP operational. Once this is accomplished, the access ports are closed, and normal BOP and/or drilling operations are resumed. Example embodiments integrate and make use of existing BOP machinery.
To the full extent permitted by law, the present U.S. Non-provisional Patent Application is made pursuant to, and hereby claims priority to and the full benefit of, U.S. Provisional Application entitled “Systems and Methods for Catastrophe Mitigation for Deep Water Oil Drilling during Blowout Preventer Failure,” having assigned Ser. No. 61/816,405 filed on Apr. 26, 2013, incorporated herein by reference in its entirety.
TECHNICAL FIELDThe present disclosure is generally related to subsea blowout preventers (BOPs) used in deep water drilling for oil, and, more particularly, mitigating disaster in the event of BOP failure.
BACKGROUNDProtocol for any oil drilling effort in deep water requires the use of a blowout preventer (BOP), which is designed to stop oil well gushers occurring due to unanticipated peaks in well pressure. These gushers can reach the rig, causing death, damage to property, and harm to the environment. Many examples of this scenario are documented, the most notable of which is the event that occurred in April of 2010 with British Petroleum (BP) and Transocean's Deep-water Horizon drill rig vessel over the Macondo Well located in the Mississippi Canyon 252 site of the Gulf of Mexico. Eleven men died and estimates of oil spill rates climbed steadily from 5,000 barrels per day up to a stunning 60,000 barrels per day.
Subsea BOPs are used extensively for the drilling of oil and natural gas, and are designed to operate in environments subject to unexpected peaks in pressure. A BOP is basically a system of valves, called rams, annular valves, or annular BOPS. These are of various types, arranged in series to form a safety redundancy. The drill column is the flow channel within the BOP and riser pipe, i.e. the piping leading from the BOP to the rig hundreds, or even thousands of feet above, and leads up to the rig. The drilling tool, called the drill pipe, leads from the rig, through the drill column and BOP, and into the earth below. To prevent blowout flows from advancing up the drill column and reaching the rig, each valve is designed to close off blowout flow in one of various manners, depending on if the drill pipe is still present in the drill column. When all these measures fail to seal in blowout flow, the last line of defense is the blind shear ram, which cuts the drill pipe, subsequently to be removed, and seals in blowout. Under such high pressure peaks the BOP can fail to operate, usually by failing to seal the flow while the drill pipe is present, or by failing to cut the drill pipe, subsequently failing to shut off blow out flow. One common failure mechanism is the drill pipe being located off center from the drill column, rendering the rams and shears inoperable. Another failure mechanism occurs when a BOP ram attempts to seal around, or cut through, the drill pipe at its tool joint. In these situations the BOP rams cannot operate properly. In the case of the Macondo Well incident, the drill pipe broke into two sections, both of which occupied the blind shear ram. These conditions presented the blind shear ram with a scenario for which it was not even designed. For these reasons, BOPs can fail. Though a small percentage of failure incidents are catastrophic, these catastrophes are costly to life, property and the environment. If a BOP fails, then the oil and natural gas escape onto the rig and into the surrounding water.
The BOP is an enclosed system, and the failed mechanisms are therefore inaccessible during such a crisis event. The depth under water further complicates efforts to reach a failed BOP. Intervention is usually possible only using remotely operated vehicles (ROVs). There is an enormous need for a means that is minimally intrusive into current BOP architecture, which provides immediate access to the failure mechanism at the BOP, simultaneously diverting the blowout spill at this location far below the rig until the BOP is rendered operable, and the spill is stopped.
PRIOR ARTPrior art provides blowout diverters at or near rig levels which allow for diversion of low pressure blowout flows. These diverters exist for land operations, as well as jack-up and floating rigs. But they provide a limited barrier between the rig and workers, and the dangerous hazards of the approaching high pressure flow. Furthermore, they offer no remedy to the failure mechanisms of the failed BOP. A means of diverting blowout at higher pressure a safer distance relative to the rig, while simultaneously providing for the mitigation of the causes of BOP failure is needed in order to assure safety to rig and crew, and gain control of the blowout.
SUMMARYExample embodiments of the present disclosure provide systems and methods of accessing and remedying a failed BOP, diverting blowout flow away from the rig, and minimizing spill duration due to BOP failure during a blowout. Briefly described, in architecture, one example embodiment of the system among others can be implemented as follows: a housing assembly, consisting of upper and lower parts, each having an integrated casing, i.e. boss, on which to mount existing BOP ram systems; an annular sealing ram positioned within the housing and between the ram block systems and able to slide within the housing, the annular ram configured to abut to a surface within one end of the housing, and the annular ram also configured to open and close a side opening in the housing ; A guide pin to keep the annular ram oriented properly for locking position; a locking mechanism configured to lock the annular ram in the closed position; a hydraulic chamber within the housing, the chamber configured for sliding the annular ram within the housing to open it, or seal it shut on the surface of the housing; and a system of seals to contain hydraulic and well pressures within and without the system.
Example embodiments of the present disclosure can also be viewed as providing methods for systems and methods of accessing and remedying a failed BOP, diverting blowout flow away from the rig, and minimizing duration of spill from a blowout caused by BOP failure. In this regard, one embodiment in such a method, among others, can be broadly described by the following: a housing mounted in the BOP stack system, consisting of upper and lower parts, each consisting of an integrated BOP ram, the upper part having a blind shear ram, and the lower part having a casing shear ram; a sealing annular ram positioned to slide within the housing to open and close the housing, to provide access into the drill column below the blind shear ram, to remedy the failure mechanism, and to provide egress for blowout flow.
Embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings in which like numerals represent like elements throughout the several figures, and in which example embodiments are shared. Embodiments of the claims may, however, be embodied in many different forms and should not be construed to be limited to the embodiments set forth herein. The examples set forth herein are non-limiting examples, and are merely examples among other possible examples. System parts are indicated by leader lines with arrowheads pointing to the part, or leader lines with dots touching the part. Part features, such as surfaces, embossments, debossments, or similar are indicated by leader lines only, touching the feature. The system disclosed herein integrates with existing systems. 3-digit numerals are used to represent elements of the invention. 2-digit numerals represent elements of existing machinery with which the invention integrates. In some cases these elements are shown in phantom line.
Protecting oil rigs from unexpected peaks in well pressure is of paramount importance. When the BOP fails under these extreme pressures, the rig, crew, and environment are almost certain to suffer loss, as in the case of the British Petroleum (BP)/Deep-water Horizon event where eleven men died and estimates of oil spill rates climbed steadily from 5,000 barrels per day up to a stunning 60,000 barrels per day.
Mitigating disastrous effects due to BOP failure is almost impossible with current drilling architecture. Proactive methods to deal with this scenario are virtually nonexistent, limited to reactive, post disaster methods for cleanup, and ad hoc methods for spill terminating. This disclosure provides a proactive solution for mitigating disaster when a BOP fails and emergency scenarios ensue. Disclosed herein in example embodiments is a minimally intrusive system to be installed into current BOP architecture for mitigating such disasters. This mitigation process is proposed as diverting blowout flow at a safe location away from the rig, while, at the same time, providing access into the drill column inside of the failed BOP. Example embodiments of systems and methods of diverting blowout flow at the failed BOP, and opening the drill column therein, are disclosed herein and may be used to install below the blind shear ram within the BOP stack, a housing unit within which a sliding annular ram opens and closes the housing. In example embodiments of this system, the current drilling protocol operates as usual, until occasion when a blowout occurs and the BOP fails. Then, the sliding annular ram opens the housing to allow blowout to flow out at this location, instead of upwards towards the rig. This opening simultaneously provides access to the drill pipe inside the drill column of the failed BOP, allowing external manipulation of the drill pipe to center it in the BOP rams for proper BOP ram function; or, if necessary, to cut the pipe, subsequently removing it from the BOP and allowing the BOP to resume normal function. Example embodiments include a hydraulic chamber within the housing to move an annular ram pipe through the housing to open and close the housing, thereby sealing the blowout flow once the failed BOP is remedied.
Water Oil Drilling during Blowout Preventer Failure. The annular ram 300 opens while the annular BOPs 12 and 13 above it close. This relieves static pressure in the BOP and diverts blowout through the side openings 110, rendering the rig completely safe and in control of remedying the situation. The drill pipe is rendered accessible through the side opening 110, such that the drill pipe may be accessed directly beneath the blind shear ram by a cutting or forcing device via ROV(s) or other means, and either cut, or centered whereby allowing the blind shear ram to cut the pipe, or other rams to seal around it to properly seal the blowout flow. Some other possible fringe benefits are retention of expensive drill mud above the annular LMRP valves; minimal downtime; and possible near term resuming of the drilling operation.
Referring now to
Claims
1. A disaster mitigation system for deep sea oil drilling, to mitigate disastrous consequences caused by blowout emergencies due to blowout preventer (BOP) failure, the system comprising of
- (a) a housing assembly;
- (b) a annular ram positioned within the housing, the ram configured to slide and abut a surface on one end of the housing, and open and close side openings in the housing;
- (c) a locking mechanism configured to lock the annular ram surface against the housing surface into closed position;
- (d) a guiding mechanism configured to align the locking mechanism to the annular ram locking features;
- (e) a hydraulic chamber within the housing to slide the annular ram into closed or open position; and
2. The disaster mitigation system of claim 1, wherein the housing assembly comprises:
- (a) an upper housing part;
- (b) a lower housing cap part;
3. The disaster mitigation system of claim 2, wherein the upper housing part comprises:
- (a) An integrated ram case on which to mount a pair of BOP blind shear rams, or any other rams of choice;
- (b) large openings on the side of this housing;
- (c) stiffener geometry to provide proper stiffness of the housing;
- (d) circumferential grooves on the inside diameter into which hydraulic seals are installed;
- (e) the inside diameter having a longitudinal groove on in which a guide pin slides;
- (f) the housing having a drilled hole through which a guide pin is installed into the annular ram;
- (g) two drilled holes to be tapped as needed for any hydraulic coupling and fluid passage;
- (h) a second, larger inside diameter forming the wall of the hydraulic chamber for the annular ram;
- (i) an axial hole through, equal in diameter to the BOP drill column; and
- (j) a series of holes drilled through the bottom circular flange of the housing to receive a plurality of threaded fasteners for affixing it to the lower housing cap.
4. The disaster mitigation system of claim 2, wherein the lower housing cap part comprises;
- (a) An integrated ram case, i.e. a large boss, on which to mount a pair of BOP casing shear rams, or any other rams of choice;
- (b) a plurality of tapped holes to which threaded fasteners affix to it the upper housing part;
- (c) a cylindrical boss onto which the annular ram slides;
- (d) the boss having grooves recessed into it to retain hydraulic seals which isolate well pressures and hydraulic pressures; and
- (e) an axial hole through, equal in diameter to the BOP drill column.
5. The disaster mitigation system of claim 1, wherein the sealing annular ram comprises:
- (a) a surface to abut the surface of the housing;
- (b) a threaded hole into which a guide pin is inserted;
- (c) two recessed slots into which the locking mechanism engages, these slots having a wedge shape or other shape which matches the locking lugs of the locking mechanism;
- (d) an outer diameter which inserts into the upper housing part inner diameter;
- (e) a second, larger outer diameter which inserts into the second larger inner diameter of the upper housing part;
- (f) this larger outer diameter surface having grooves in which to insert hydraulic seals which isolate well pressure from the hydraulic chamber;
- (g) a step surface between the two diameters of (d) and (e) above, on which hydraulic pressure is applied for opening the annular ram;
- (h) an inner diameter hole through, matching the diameter of the BOP drill column;
- (i) a second, larger inner diameter which slides over the lower housing cap part;
- (j) a flat surface on the end of the annular ram just above the sealing surface; and
- (k) a flat surface between the two inner diameters which has equal surface area to the flat surface of item (j) above to prevent a force imbalance on the annular ram due to well pressures on unequal opposing surfaces.
6. The disaster mitigation system of claim 1, wherein the locking mechanism of claim comprises two lugs, each inserted into the upper housing part through holes on sides opposite each other; each lug having wedge shape cam geometry or other geometry which matches the recessed slots in the annular ram to provide a tightening effect.
7. The disaster mitigation system of claim 1, wherein the guiding mechanism comprises a guide pin inserted through a hole in the upper housing part, and threading into the annular ram, then sliding in the longitudinal slot of the upper housing part whereby the annular ram with its recessed slots maintain proper alignment with the locking lugs of claim 6.
8. A method of mitigating blowout disaster when the Blowout Preventer (BOP) fails, this method comprising of pre-mounting a housing assembly in the BOP as a Drill-Through-Equipment (DTE) system, the housing assembly located in the BOP stack, below the EDS connecting flange, the housing assembly comprising of:
- (a) an upper housing part being equipped with an integrated blind shear ram;
- (b) the lower housing cap part being equipped with an integrated casing shear or other chosen ram;
- (c) a sliding annular ram within the housing configured to open and close side openings in the housing;
- (d) a locking mechanism whereby the annular ram is locked into closed position;
9. A method of mitigating blowout disaster in claim 8 further comprising opening the housing's side openings in the housing assembly, whereby gaining access to and cutting the drill pipe, restoring function to the BOP.
10. A method of mitigating blowout disaster in claim 8, further comprising diverting blowout through said side openings in housing.
11. A method of mitigating blowout disaster in claim 8, further comprising closing the annular ram once BOP function is restored, whereby the spill is stopped.
12. A method of mitigating blowout disaster in claim 8, further comprising locking the sliding annular ram into closed position with a locking mechanism.
13. A system of mitigating blowout disasters when the BOP fails, comprising a means for pre-mounting a housing in the BOP as a Drill-Through-Equipment (DTE) system, the housing assembly comprising:
- (a) a housing means, equipped with integrated BOP blind shear ram, and a casing shear or other BOP ram of choice;
- (b) a sealing means positioned inside the housing for opening and closing the housing;
- (c) a means for locking the sealing means into closed position.
14. A system of mitigating blowout disasters of claim 13, further comprising a means for sliding the sealing means in the housing to open side openings in the housing, whereby gaining access to the drill pipe.
15. A system of mitigating blowout disasters of claim 14, further comprising a means for diverting total blowout through said side openings, whereby protecting the drill rig.
16. A system of mitigating blowout disasters of claim 14, further comprising a means for remedying the failed BOP by said means for accessing said drill pipe through said side openings with cutting and/or forcing tools.
17. A system of mitigating blowout disasters of claim 14, further comprising a means for closing the side openings in the housing, whereby stopping the spill.
Type: Application
Filed: Apr 23, 2014
Publication Date: Oct 29, 2015
Inventor: Kenton Fleming (Marietta, GA)
Application Number: 14/259,632