CA1239090A - Subsea bop stack control system - Google Patents
Subsea bop stack control systemInfo
- Publication number
- CA1239090A CA1239090A CA000472499A CA472499A CA1239090A CA 1239090 A CA1239090 A CA 1239090A CA 000472499 A CA000472499 A CA 000472499A CA 472499 A CA472499 A CA 472499A CA 1239090 A CA1239090 A CA 1239090A
- Authority
- CA
- Canada
- Prior art keywords
- control system
- hydraulic
- subsea
- hydraulic control
- blowout preventer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000012530 fluid Substances 0.000 claims abstract description 50
- 241000387514 Waldo Species 0.000 description 12
- 238000005553 drilling Methods 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 230000002265 prevention Effects 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 230000002706 hydrostatic effect Effects 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 241000282320 Panthera leo Species 0.000 description 2
- 230000004941 influx Effects 0.000 description 2
- 208000037805 labour Diseases 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 230000001960 triggered effect Effects 0.000 description 2
- 239000003643 water by type Substances 0.000 description 2
- 241000191291 Abies alba Species 0.000 description 1
- 241000272470 Circus Species 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 239000006210 lotion Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
- 239000003016 pheromone Substances 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
- E21B33/03—Well heads; Setting-up thereof
- E21B33/035—Well heads; Setting-up thereof specially adapted for underwater installations
- E21B33/0355—Control systems, e.g. hydraulic, pneumatic, electric, acoustic, for submerged well heads
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Earth Drilling (AREA)
Abstract
Abstract of the Disclosure An improvement is provided in a system for controlling a subsea blowout preventer in which blowout preventer functions are operated by a hydraulic control system. The improvement resides in a control system which has at least two elements and at least one back up control system. The control system includes a subsea pressure compensated reservoir for replenish-ing the supply of hydraulic fluid, and an electric motor, supplied with electrical command energy from the surface, to operate a hydraulic pump which operates in conjunction with the BOP hydraulic control system. One back up control system is a standby second electric motor, supplied with electrical command energy from the surface, to operate a hydraulic pump which operates in conjunction with the BOP hydraulic control system. A second back up control system is an acoustical unit including a transducer and a subsea acoustic receiver to oper-ate the BOP hydraulic control system drawing hydraulic fluid from the subsea hydraulic accumulators associated with the hydraulic control system. Having two back up, standby systems, enhances the reliability of the BOP control. The total hydraulic control system is housed in a pressure compensated reservoir located at the usual pod locations. Two pods are used for additional redundancy.
Description
LO
This invention relates to a subset BOY blow Out Preventer) control system.
Drilling operations conducted from floating vessels normally involve the use of marine risers connecting the floating vessel with the Waldo and other equipment on the ocean floor. Such equipment usually includes a blowout preventer control system.
Normally, a hydrostatic pressure of the drilling fluid column in the well is greater than the pressure of the format o lion fluid, thus preventing the flow of formation fluids into the Wilbur. When a formation with a pressure greater than the hydrostatic pressure in the well is encountered, format lion fluids are able to enter the well. As the initial influx of formation fluids as hydrostatic pressure in the well is encountered, formation fluids are able to enter the well. The initial influx of formation fluids is commonly referred to as a "kick". As long as hydrostatic pressures control the well, the blowout preventers are in the open position. Should a kick occur, however, blowout prevention equipment and access stories are actuated to close the well.
The purpose of the blowout preventer system in floating drilling operations is to provide control when a kick occurs and to provide a means of circulating, conditioning, and returning the Wilbur to a static condition. Usually, the TV
blowout prevention system includes blowout preventers, a means of controlling release of fluid from the well, and a means of pumping fluid into the well.
One of the types of blowout preventers is the so-called "ram type". A blowout preventer of the ram type generally comprises a hollow body member having aligned pipe openings in one pair of opposite walls to provide a pipe passage there through, - a pair of horizontally slid able t rams arranged for movement toward and away from the pipe passage in the preventer body so as to seal the pipe passage when the rams are in the closed position.
Each ram carries a resilient sealing member or valve head arranged to engage its cooperating ram in a fluid-tight manner. One set of rams when closed together has a hole extending there through which is of slightly smaller diameter than the diameter of a drill pipe against which it is adapted to seal in a fluid-tight manner.
The other pair of rams in the blowout preventer, known as blind rams have straight-edged resilient sealing members adapted to seal against each other when there is no pipe or tubing string extending through the blowout preventer.
The rams in one type of blowout preventer are closed manually by an operator turning hand wheels connected to threaded valve stems which in turn are connected to the rams. Thus, the blowout preventer is closed in the same manner that two valves would be closed that are set at 180 to each other to close one against the other. It is obvious that manually-actuated valves could not be used in drilling underwater wells.
' - 2 39~
The rams in another type of blowout preventer are hydra-locally activated. While these are suitable on land, the use of hydraulically-operated blowout preventers for drilling underwater wells has not proved entirely satisfactory due to the fact that the hydraulic pressure lines may be easily ruptured and the pros-sure drop in the hydraulic lines due to friction loss reduces the amount of available pressure to be supplied in the rams of the blowout preventer. The pressure drop in the hydraulic lines may be overcome only by using very large diameter hydraulic lines, lo but these are very heavy and cumbersome to handle in offshore operations where the drilling platform or vessel may be several hundred feet above the Waldo position on the ocean floor.
Relatively high fluid pressure is normally maintained in these hoses and they frequently fail under working and flex-use conditions at such pressures. Replacement of the hoses to the individual blowout preventers is costly in that it is time consuming and requires the use of divers, or in deep water install lotions may require retrieval of the blowout prevention equip-mint to the vessel for replacement of the hoses. Having a multi-plicity of hoses running from the vessel to the ocean floor increases the incidence of failure and also gives rise to hose entangling which often requires the services of a diver for u~tanglement. Such hydraulic lines connect the valves to be controlled to a hydraulic fluid source located on the surface of the platform. These lines are advantageously flexible, thereby allowing them to be handled easily and making it possible to place the lines in the well with the lone already connected to the Lo valves, the lines and the valves being installed together. These devices operate satisfactorily when the Waldo is not at too great a depth, i.e., when the length of the flexible lines is not too long and, in practice, does not exceed about 300 metros.
Beyond this length, the response time of the device, i.e., the time required for opening or closing the valve, becomes undesirably long. This is a serious disadvantage when it is necessary to close a valve very rapidly so as to prevent the blowout of a well.
This delay is due mainly to the fact that use is made of a flexible line which has the drawback of expanding as the pressure of the hydraulic fluid increases. It will be noted that the response time increases with the length of the lines.
To overcome this drawback, different solutions have been proposed. A first solution consists in using a battery of hydraulic fluid accumulators of high capacity on the surface so as to obtain a large hydraulic fluid flow in the lines when the valve is opened or closed. It was thus hoped to reduce the control time. In fact, the lines used are generally of small diameter. This results in significant pressure drops which limit and stabilize the hydraulic fluid flow-rate in the lines.
Other solutions consist of using additional hydraulic fluid accumulators and placing them near the Waldo at sea bottom, in the immediate vicinity of the valves to be controlled.
In one of these solutions, the accumulators are controlled by means of hydraulic control valves actuated from the surface I
through hydraulic lines connecting these control valves to the surface. The opening or closing of these control valves is accomplished by varying the hydraulic pressure in the hydraulic control lines. The hydraulic control lines are used only for controlling the main underwater valve, through the control valves, but not to furnish the hydraulic energy necessary for opening or closing the main underwater valve. In that system, the hydraulic control circuits and the hydraulic actuating circuits it furnishing the energy) are separate.
lo Another solution is described in the review "Off-Shore"
of May, 1979, pages 124-126. A battery of hydraulic fluid accumu-labors is also used near the Waldo at sea bottom in the vicinity of the valves to be controlled. The accumulators are actuated by means of pyrotechnical valves triggered from the surface by means of an electric cable. This solution, while yielding remarkable per-pheromones, is complicated because it makes use of both hydraulic techniques and electrical techniques. Moreover, when the pyre-technical valves have been triggered, they can no longer be used;
the system will thus not operate repetitively.
Generally, the use of accumulators placed near the Waldo at sea bottom entails many drawbacks. They are, in fact, cumbersome and must be protected from shocks and from the fluids surrounding them. In addition, the pressure of the hydra-fig fluid filling the accumulators must be adjusted from the surface, taking into account the pressures prevailing in the well at the depth at which they are to be placed. This pressure adjust-mint calls or an auxiliary fluid source as well as a skilled operator. Similarly, when the accumulators are empty, it is necessary to bring the entire device up to the surface in order to recharge the accumulators. The device can thus be used for only a limited number of valve-actuation repetitions.
The elimination of all high pressure hydraulic hoses from the vessel to the ocean floor equipment was therefore desirable. One proposed attempt to eliminate such high pressure hydraulic lines was suggested by ROY. Neat, in US. Patent 4,046,191, patented September 6, 1977, who provided apparatus for drilling a subset well from a drilling platform at the surface of a body of water.
The apparatus included a riser conduit extending between the plats form and the well and at least one blowout preventer connected to the riser conduit near the lower end thereof. At least one fluid --bypass conduit provided at least one fluid flow path from the well at a point below the blowout preventer to the lower exterior portion of the riser conduit at a point above the uppermost blowout proven-ton; and regulators were provided in the bypass conduit for regular tying fluid flow through the bypass conduit.
JOY. Hebrew et at, in US. Patent 3,250,336, patented May 10, 1966, and Canadian Patent 788,789, patented July 2, 1968, attempted to solve such problem by providing an electrically-operated blowout preventer which may be operated by a single multi-conductor electric transmission line extending from a drilling platform above the surface of a body of water to the blow-out preventer and Waldo apparatus positioned near the ocean floor.
That blowout preventer was secured in the Waldo assembly and was provided with rams to close about a pipe string, elect trically-actuated operator means were operatively connected to the blowout preventer and were carried thereby, the operator means including electric motor and linkage means including gear means. Power transmission means extended from the blowout preventer to the operating platform on the surface of the water, the power transmission means including current leads to the electric - cally-actuated operator means and circuit means on the platform o then connected the current leads to a power source.
P.R. Rowley in US. Patent 3,496,999, patented February 14, 1970, and a Canadian Patent, 888,546, patented December 21, 1971, attempted to solve such problem by providing a system for controlling benthos blowout prevention equipment by supplying only electrical energy to the benthos Waldo equipment. That patent provided control of fluid operated equipment on the ocean floor during drilling operations conducted from a floating vessel through a riser extending between the ocean floor and the vessel.
Hydraulic fluid was stored in a benthos reservoir, from which it is pumped to a group of accumulators by a motor pump assembly.
From the accumulators, the pressurized hydraulic fluid was piped through a valve and manifold assembly to the individual components of the blowout preventer stack. The valve and manifold assembly consisted of a series of electrically actuated valves which controlled the fluid applied to the individual blowout preventer units, and which were electrically controlled from the vessel to provide means for controlling the blowout preventers from the ~39()9~
vessel. The reservoir, accumulators, and motor pump assembly were each arranged annularly around the lower end of the riser adjacent the blowout preventer stack.
V. Bouncily et at in US. Patent 4,337,829, patented July 6, 1982, provided a control system for subset wilds adapted to control subset oil wells in deep waters (down to 600 meters of water depth). That patented system included an above-water control console and a modular underwater control unit coupled thereto acoustically, by electric cable and by lo flow lines. The underwater control module comprised an electronic unit containing the control circuitry, an electron hydraulic unit for operating the Waldo valves and a hydraulic-electronic electrical interface. A power generator is also included within the underwater control module. The electron hydraulic unit is coupled to a submerged Christmas tree. In operation, the control signals for the Waldo were transmitted, after suitable codification, from the surface control console to the underwater electronics unit using one of the three-transmission links. The signals after recodification were 20. sent through the electrical interface to the hydraulic unit which operated the Waldo valves.
B. Dorms et at, in US. Patent 4,442,902, patented April 17, 1984, provided a hydraulic method and apparatus for the remote hydraulic control of a device connected to a hydra-fig fluid source by means of at least one flexible line filled with hydraulic fluid. Hydraulic energy was accumulated in the flexible line by increasing the pressure of the hydraulic fluid 3~3V~
on the line so that the line increased in volume. The pressure was maintained in the line so that the hydraulic energy thus accumulated by the expansive deformation of the line may be used rapidly to control the device.
Thus, in general terms, in the conventional control system, the fluid used to operate the functions on the BOY
stack was mixed, pressured, and delivered from a hydraulic unit on the surface. The fluid was passed by pilot valves through a hose bundle to a subset pod (an assembly of valves and regulators etc.). Two pods were conventionally used with the piloted control valves (located in the subset pod) directed fluid to the various functions on the BOY stack. The command was hydraulic pressure transmitted through small hoses clustered in hose bundles.
As noted above, such system was considered ideally suited for operations in shallow waters owing to system's basic reliability and simplicity in operation and maintenance. However, for deep water drilling (depths of over 400 meters) the system was considered unsuitable because of the following reasons:
namely (a) it had a slow response time, (b) high pressures were involved, (c) it required large hose bundles, and (d) there was no feedback.
Accordingly, a main object of this invention is to provide an imp proved system for subset wilds.
Another object of this invention is to provide a blowout preventer control system whereby the blowout preventer may be opened or closed remotely, as from a drilling platform or vessel positioned on the surface of the water.
Yet another object of this invention is to provide an electro-hydraulic blowout preventer control system.
Yet another object of this invention is to provide a blowout preventer control system with the blowout prevention equipment positioned on the ocean floor without the need for high pressure, hydraulic control lines extending between the vessel and the blowout preventer.
lo A further object of this invention is to provide a blowout preventer control system with the blowout prevention hydraulic control equipment located on the ocean floor, but operated remotely from the vessel.
Still another object of this invention is to provide a blowout preventer control system with the hydraulic control fluid stored and distributed to the individual blowout preventers from equipment positioned adjacent the ocean floor.
Yet another object of this invention is to provide a backup blowout preventer control system in which the blowout preventer control equipment and a backup hydraulic reservoir are positioned adjacent the ocean floor and which are controlled by a backup standby electrical system.
.
3C~)9~
The essence of the present invention is embodied in an improved system for controlling a subset blowout preventer in which blowout preventer functions are operated by a hydraulic control system, the improved control system comprising ': (a) a subset pressure compensated reservoir for replenishing the supply of hydraulic fluid, (b) a primary electric motor, supplied with electrical command energy from the surface, to operate a hydra-fig pump which operates in conjunction with the BOY hydraulic control system, and (c) a standby second electric motor, supplied with electrical command energy from the surface, to operate a hydraulic pump which operates in conjunction with the BOY hydra-fig control system.
By one feature of this invention the electrical command energy for the standby electric motor is generated separately from the electric command energy for the primary electric motor.
By another feature of this invention, the system includes a backup acoustic control unit including a transducer and a subset acoustic receiver to operate the BOY hydraulic control system drawing hydraulic fluid from the subset hydraulic accumulators associated with the hydraulic control system.
By yet another feature of this invention, all the subset elements of the system are disposed in a subset pod, and conventionally two pods are used as additional redundancy.
-- 11 -- .
9~)9~
Thus, it is seen that the system of this invention transfers all the surface components of a conventional control system to subset except a multiplexed signal line and an electrical power circuit line. The working principle for the total control system is that the commands are electric signals transmitted through a cluster of wires that operate solenoid valves in the hydraulic control system in the subset pod. The solenoid valves direct hydraulic fluid to actuate the control - valves, which in turn direct hydraulic fluid to various lo functions on the stack. All control valves, solenoid valves, multiplexing receiver unit, pump and motor, etc., are housed in a subset chamber. Hydraulic fluid required to operate the functions is also available at subset in a subset pressure compensated reservoir.
In the accompanying drawing, the single figure is a schematic representation of the subset BOY control system of one embodiment of this invention.
As seen in the single figure, a drill ship 10 provides a conventional drill string lo which includes a blowout preventer (BEEP 11. The BOY controls are situated within a subset pod 12. two pods are preferably used for redundancy.
The BOY functions are controlled by a hydraulic control system 13, whose supply of hydraulic fluid originates in subset accumulators 15 provided with a subset pressure compensated reservoir 14 for replenishing the charge in the subset accumu-labors 15 in a closed loop system. --3C.~V~
The primary control of this electro-hydraulic control system 13 is by a multiplexed signal command from the surface that operate solenoid valves in the subset pod. Solenoid valves direct fluid to actuate the control valves which in turn direct hydraulic fluid to various functions on the BOY stack. On multiplexed signal command from the surface hydraulic fluid from the subset accumulators 15 is diverted through the control valves to the various BOY functions which in turn discharge into the pressure compensated reservoir.
o Simultaneously, the motor 16 and pump 17 assembly is activated to replenish the charge in the accumulators by circus feting hydraulic fluid from the pressure compensated reservoir.
Power to the electric motor 16 is via a multiplexed signal line -and electing power line 18 from the rig electric supply 19 on the drill shop 10.
The secondary control of the electro-hydraulic control system 13 is by secondary or backup standby generator and stand-by multiplexing unit 22. Power to standby motor 20 is via a standby multiplexed signal line and standby electric power line 22.
Tertiary or further backup control is provided by a transducer 24 powered by an acoustic backup control unit 25 on board the drill ship 10. Acoustic signals 26 from trays-dicer 24 are received by acoustic receiver 27 which directly activates the hydraulic control system 13 using the hydraulic fluid in the subset accumulators 15 to drive the hydraulic control system.
_ 13 -n lo I
The operation of the BOY functions is the same as in any other hydraulically controlled BOY. However, the concept of transferring most of the units to a subset unit has the following advantages , namely:
(a fast response times owing to the control units being located in the proximity of the BOY stack functions;
(b) no bulky hoses from the surface for supply of hydraulic fluid from the surface; and (c) the use of standard equipment in the subset tank.
This invention relates to a subset BOY blow Out Preventer) control system.
Drilling operations conducted from floating vessels normally involve the use of marine risers connecting the floating vessel with the Waldo and other equipment on the ocean floor. Such equipment usually includes a blowout preventer control system.
Normally, a hydrostatic pressure of the drilling fluid column in the well is greater than the pressure of the format o lion fluid, thus preventing the flow of formation fluids into the Wilbur. When a formation with a pressure greater than the hydrostatic pressure in the well is encountered, format lion fluids are able to enter the well. As the initial influx of formation fluids as hydrostatic pressure in the well is encountered, formation fluids are able to enter the well. The initial influx of formation fluids is commonly referred to as a "kick". As long as hydrostatic pressures control the well, the blowout preventers are in the open position. Should a kick occur, however, blowout prevention equipment and access stories are actuated to close the well.
The purpose of the blowout preventer system in floating drilling operations is to provide control when a kick occurs and to provide a means of circulating, conditioning, and returning the Wilbur to a static condition. Usually, the TV
blowout prevention system includes blowout preventers, a means of controlling release of fluid from the well, and a means of pumping fluid into the well.
One of the types of blowout preventers is the so-called "ram type". A blowout preventer of the ram type generally comprises a hollow body member having aligned pipe openings in one pair of opposite walls to provide a pipe passage there through, - a pair of horizontally slid able t rams arranged for movement toward and away from the pipe passage in the preventer body so as to seal the pipe passage when the rams are in the closed position.
Each ram carries a resilient sealing member or valve head arranged to engage its cooperating ram in a fluid-tight manner. One set of rams when closed together has a hole extending there through which is of slightly smaller diameter than the diameter of a drill pipe against which it is adapted to seal in a fluid-tight manner.
The other pair of rams in the blowout preventer, known as blind rams have straight-edged resilient sealing members adapted to seal against each other when there is no pipe or tubing string extending through the blowout preventer.
The rams in one type of blowout preventer are closed manually by an operator turning hand wheels connected to threaded valve stems which in turn are connected to the rams. Thus, the blowout preventer is closed in the same manner that two valves would be closed that are set at 180 to each other to close one against the other. It is obvious that manually-actuated valves could not be used in drilling underwater wells.
' - 2 39~
The rams in another type of blowout preventer are hydra-locally activated. While these are suitable on land, the use of hydraulically-operated blowout preventers for drilling underwater wells has not proved entirely satisfactory due to the fact that the hydraulic pressure lines may be easily ruptured and the pros-sure drop in the hydraulic lines due to friction loss reduces the amount of available pressure to be supplied in the rams of the blowout preventer. The pressure drop in the hydraulic lines may be overcome only by using very large diameter hydraulic lines, lo but these are very heavy and cumbersome to handle in offshore operations where the drilling platform or vessel may be several hundred feet above the Waldo position on the ocean floor.
Relatively high fluid pressure is normally maintained in these hoses and they frequently fail under working and flex-use conditions at such pressures. Replacement of the hoses to the individual blowout preventers is costly in that it is time consuming and requires the use of divers, or in deep water install lotions may require retrieval of the blowout prevention equip-mint to the vessel for replacement of the hoses. Having a multi-plicity of hoses running from the vessel to the ocean floor increases the incidence of failure and also gives rise to hose entangling which often requires the services of a diver for u~tanglement. Such hydraulic lines connect the valves to be controlled to a hydraulic fluid source located on the surface of the platform. These lines are advantageously flexible, thereby allowing them to be handled easily and making it possible to place the lines in the well with the lone already connected to the Lo valves, the lines and the valves being installed together. These devices operate satisfactorily when the Waldo is not at too great a depth, i.e., when the length of the flexible lines is not too long and, in practice, does not exceed about 300 metros.
Beyond this length, the response time of the device, i.e., the time required for opening or closing the valve, becomes undesirably long. This is a serious disadvantage when it is necessary to close a valve very rapidly so as to prevent the blowout of a well.
This delay is due mainly to the fact that use is made of a flexible line which has the drawback of expanding as the pressure of the hydraulic fluid increases. It will be noted that the response time increases with the length of the lines.
To overcome this drawback, different solutions have been proposed. A first solution consists in using a battery of hydraulic fluid accumulators of high capacity on the surface so as to obtain a large hydraulic fluid flow in the lines when the valve is opened or closed. It was thus hoped to reduce the control time. In fact, the lines used are generally of small diameter. This results in significant pressure drops which limit and stabilize the hydraulic fluid flow-rate in the lines.
Other solutions consist of using additional hydraulic fluid accumulators and placing them near the Waldo at sea bottom, in the immediate vicinity of the valves to be controlled.
In one of these solutions, the accumulators are controlled by means of hydraulic control valves actuated from the surface I
through hydraulic lines connecting these control valves to the surface. The opening or closing of these control valves is accomplished by varying the hydraulic pressure in the hydraulic control lines. The hydraulic control lines are used only for controlling the main underwater valve, through the control valves, but not to furnish the hydraulic energy necessary for opening or closing the main underwater valve. In that system, the hydraulic control circuits and the hydraulic actuating circuits it furnishing the energy) are separate.
lo Another solution is described in the review "Off-Shore"
of May, 1979, pages 124-126. A battery of hydraulic fluid accumu-labors is also used near the Waldo at sea bottom in the vicinity of the valves to be controlled. The accumulators are actuated by means of pyrotechnical valves triggered from the surface by means of an electric cable. This solution, while yielding remarkable per-pheromones, is complicated because it makes use of both hydraulic techniques and electrical techniques. Moreover, when the pyre-technical valves have been triggered, they can no longer be used;
the system will thus not operate repetitively.
Generally, the use of accumulators placed near the Waldo at sea bottom entails many drawbacks. They are, in fact, cumbersome and must be protected from shocks and from the fluids surrounding them. In addition, the pressure of the hydra-fig fluid filling the accumulators must be adjusted from the surface, taking into account the pressures prevailing in the well at the depth at which they are to be placed. This pressure adjust-mint calls or an auxiliary fluid source as well as a skilled operator. Similarly, when the accumulators are empty, it is necessary to bring the entire device up to the surface in order to recharge the accumulators. The device can thus be used for only a limited number of valve-actuation repetitions.
The elimination of all high pressure hydraulic hoses from the vessel to the ocean floor equipment was therefore desirable. One proposed attempt to eliminate such high pressure hydraulic lines was suggested by ROY. Neat, in US. Patent 4,046,191, patented September 6, 1977, who provided apparatus for drilling a subset well from a drilling platform at the surface of a body of water.
The apparatus included a riser conduit extending between the plats form and the well and at least one blowout preventer connected to the riser conduit near the lower end thereof. At least one fluid --bypass conduit provided at least one fluid flow path from the well at a point below the blowout preventer to the lower exterior portion of the riser conduit at a point above the uppermost blowout proven-ton; and regulators were provided in the bypass conduit for regular tying fluid flow through the bypass conduit.
JOY. Hebrew et at, in US. Patent 3,250,336, patented May 10, 1966, and Canadian Patent 788,789, patented July 2, 1968, attempted to solve such problem by providing an electrically-operated blowout preventer which may be operated by a single multi-conductor electric transmission line extending from a drilling platform above the surface of a body of water to the blow-out preventer and Waldo apparatus positioned near the ocean floor.
That blowout preventer was secured in the Waldo assembly and was provided with rams to close about a pipe string, elect trically-actuated operator means were operatively connected to the blowout preventer and were carried thereby, the operator means including electric motor and linkage means including gear means. Power transmission means extended from the blowout preventer to the operating platform on the surface of the water, the power transmission means including current leads to the electric - cally-actuated operator means and circuit means on the platform o then connected the current leads to a power source.
P.R. Rowley in US. Patent 3,496,999, patented February 14, 1970, and a Canadian Patent, 888,546, patented December 21, 1971, attempted to solve such problem by providing a system for controlling benthos blowout prevention equipment by supplying only electrical energy to the benthos Waldo equipment. That patent provided control of fluid operated equipment on the ocean floor during drilling operations conducted from a floating vessel through a riser extending between the ocean floor and the vessel.
Hydraulic fluid was stored in a benthos reservoir, from which it is pumped to a group of accumulators by a motor pump assembly.
From the accumulators, the pressurized hydraulic fluid was piped through a valve and manifold assembly to the individual components of the blowout preventer stack. The valve and manifold assembly consisted of a series of electrically actuated valves which controlled the fluid applied to the individual blowout preventer units, and which were electrically controlled from the vessel to provide means for controlling the blowout preventers from the ~39()9~
vessel. The reservoir, accumulators, and motor pump assembly were each arranged annularly around the lower end of the riser adjacent the blowout preventer stack.
V. Bouncily et at in US. Patent 4,337,829, patented July 6, 1982, provided a control system for subset wilds adapted to control subset oil wells in deep waters (down to 600 meters of water depth). That patented system included an above-water control console and a modular underwater control unit coupled thereto acoustically, by electric cable and by lo flow lines. The underwater control module comprised an electronic unit containing the control circuitry, an electron hydraulic unit for operating the Waldo valves and a hydraulic-electronic electrical interface. A power generator is also included within the underwater control module. The electron hydraulic unit is coupled to a submerged Christmas tree. In operation, the control signals for the Waldo were transmitted, after suitable codification, from the surface control console to the underwater electronics unit using one of the three-transmission links. The signals after recodification were 20. sent through the electrical interface to the hydraulic unit which operated the Waldo valves.
B. Dorms et at, in US. Patent 4,442,902, patented April 17, 1984, provided a hydraulic method and apparatus for the remote hydraulic control of a device connected to a hydra-fig fluid source by means of at least one flexible line filled with hydraulic fluid. Hydraulic energy was accumulated in the flexible line by increasing the pressure of the hydraulic fluid 3~3V~
on the line so that the line increased in volume. The pressure was maintained in the line so that the hydraulic energy thus accumulated by the expansive deformation of the line may be used rapidly to control the device.
Thus, in general terms, in the conventional control system, the fluid used to operate the functions on the BOY
stack was mixed, pressured, and delivered from a hydraulic unit on the surface. The fluid was passed by pilot valves through a hose bundle to a subset pod (an assembly of valves and regulators etc.). Two pods were conventionally used with the piloted control valves (located in the subset pod) directed fluid to the various functions on the BOY stack. The command was hydraulic pressure transmitted through small hoses clustered in hose bundles.
As noted above, such system was considered ideally suited for operations in shallow waters owing to system's basic reliability and simplicity in operation and maintenance. However, for deep water drilling (depths of over 400 meters) the system was considered unsuitable because of the following reasons:
namely (a) it had a slow response time, (b) high pressures were involved, (c) it required large hose bundles, and (d) there was no feedback.
Accordingly, a main object of this invention is to provide an imp proved system for subset wilds.
Another object of this invention is to provide a blowout preventer control system whereby the blowout preventer may be opened or closed remotely, as from a drilling platform or vessel positioned on the surface of the water.
Yet another object of this invention is to provide an electro-hydraulic blowout preventer control system.
Yet another object of this invention is to provide a blowout preventer control system with the blowout prevention equipment positioned on the ocean floor without the need for high pressure, hydraulic control lines extending between the vessel and the blowout preventer.
lo A further object of this invention is to provide a blowout preventer control system with the blowout prevention hydraulic control equipment located on the ocean floor, but operated remotely from the vessel.
Still another object of this invention is to provide a blowout preventer control system with the hydraulic control fluid stored and distributed to the individual blowout preventers from equipment positioned adjacent the ocean floor.
Yet another object of this invention is to provide a backup blowout preventer control system in which the blowout preventer control equipment and a backup hydraulic reservoir are positioned adjacent the ocean floor and which are controlled by a backup standby electrical system.
.
3C~)9~
The essence of the present invention is embodied in an improved system for controlling a subset blowout preventer in which blowout preventer functions are operated by a hydraulic control system, the improved control system comprising ': (a) a subset pressure compensated reservoir for replenishing the supply of hydraulic fluid, (b) a primary electric motor, supplied with electrical command energy from the surface, to operate a hydra-fig pump which operates in conjunction with the BOY hydraulic control system, and (c) a standby second electric motor, supplied with electrical command energy from the surface, to operate a hydraulic pump which operates in conjunction with the BOY hydra-fig control system.
By one feature of this invention the electrical command energy for the standby electric motor is generated separately from the electric command energy for the primary electric motor.
By another feature of this invention, the system includes a backup acoustic control unit including a transducer and a subset acoustic receiver to operate the BOY hydraulic control system drawing hydraulic fluid from the subset hydraulic accumulators associated with the hydraulic control system.
By yet another feature of this invention, all the subset elements of the system are disposed in a subset pod, and conventionally two pods are used as additional redundancy.
-- 11 -- .
9~)9~
Thus, it is seen that the system of this invention transfers all the surface components of a conventional control system to subset except a multiplexed signal line and an electrical power circuit line. The working principle for the total control system is that the commands are electric signals transmitted through a cluster of wires that operate solenoid valves in the hydraulic control system in the subset pod. The solenoid valves direct hydraulic fluid to actuate the control - valves, which in turn direct hydraulic fluid to various lo functions on the stack. All control valves, solenoid valves, multiplexing receiver unit, pump and motor, etc., are housed in a subset chamber. Hydraulic fluid required to operate the functions is also available at subset in a subset pressure compensated reservoir.
In the accompanying drawing, the single figure is a schematic representation of the subset BOY control system of one embodiment of this invention.
As seen in the single figure, a drill ship 10 provides a conventional drill string lo which includes a blowout preventer (BEEP 11. The BOY controls are situated within a subset pod 12. two pods are preferably used for redundancy.
The BOY functions are controlled by a hydraulic control system 13, whose supply of hydraulic fluid originates in subset accumulators 15 provided with a subset pressure compensated reservoir 14 for replenishing the charge in the subset accumu-labors 15 in a closed loop system. --3C.~V~
The primary control of this electro-hydraulic control system 13 is by a multiplexed signal command from the surface that operate solenoid valves in the subset pod. Solenoid valves direct fluid to actuate the control valves which in turn direct hydraulic fluid to various functions on the BOY stack. On multiplexed signal command from the surface hydraulic fluid from the subset accumulators 15 is diverted through the control valves to the various BOY functions which in turn discharge into the pressure compensated reservoir.
o Simultaneously, the motor 16 and pump 17 assembly is activated to replenish the charge in the accumulators by circus feting hydraulic fluid from the pressure compensated reservoir.
Power to the electric motor 16 is via a multiplexed signal line -and electing power line 18 from the rig electric supply 19 on the drill shop 10.
The secondary control of the electro-hydraulic control system 13 is by secondary or backup standby generator and stand-by multiplexing unit 22. Power to standby motor 20 is via a standby multiplexed signal line and standby electric power line 22.
Tertiary or further backup control is provided by a transducer 24 powered by an acoustic backup control unit 25 on board the drill ship 10. Acoustic signals 26 from trays-dicer 24 are received by acoustic receiver 27 which directly activates the hydraulic control system 13 using the hydraulic fluid in the subset accumulators 15 to drive the hydraulic control system.
_ 13 -n lo I
The operation of the BOY functions is the same as in any other hydraulically controlled BOY. However, the concept of transferring most of the units to a subset unit has the following advantages , namely:
(a fast response times owing to the control units being located in the proximity of the BOY stack functions;
(b) no bulky hoses from the surface for supply of hydraulic fluid from the surface; and (c) the use of standard equipment in the subset tank.
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a system for controlling a subsea blowout preventer in which blowout preventer functions are operated by a hydraulic control system, the improved control system comprising:
(a) a subsea pressure compensated reservoir for replenishing the supply of hydraulic fluid, (b) a primary motor, supplied with electrical command energy from the surface, to operate a hydraulic pump which operates in conjunction with said BOP hydraulic control system, and (c) a standby second electric motor, supplied with electrical command energy from the surface, to operate a electric pump which operates in conjunc-tion with said BOP hydraulic control system.
(a) a subsea pressure compensated reservoir for replenishing the supply of hydraulic fluid, (b) a primary motor, supplied with electrical command energy from the surface, to operate a hydraulic pump which operates in conjunction with said BOP hydraulic control system, and (c) a standby second electric motor, supplied with electrical command energy from the surface, to operate a electric pump which operates in conjunc-tion with said BOP hydraulic control system.
2. The system of claim 1 wherein said electrical command energy for said standby electric motor is generated separately from said electric command energy for said primary electric motor.
3. The improved system of claim 1 including a second backup acoustic control unit including a transducer and a sub-sea acoustic receiver to operate the BOP hydraulic control system drawing hydraulic fluid from at least one subsea hydraulic accumulator to drive said hydraulic control system.
4. The improved system of claim 1 wherein all said claimed elements are disposed within a single subsea pod.
5. The improved system of claim 1 wherein all said claimed elements are each disposed within two separate subsea pods for added redundancy.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000472499A CA1239090A (en) | 1985-01-21 | 1985-01-21 | Subsea bop stack control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000472499A CA1239090A (en) | 1985-01-21 | 1985-01-21 | Subsea bop stack control system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1239090A true CA1239090A (en) | 1988-07-12 |
Family
ID=4129630
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000472499A Expired CA1239090A (en) | 1985-01-21 | 1985-01-21 | Subsea bop stack control system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1239090A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007045260A1 (en) * | 2005-10-19 | 2007-04-26 | Cooper Cameron Corporation | Subsea equipment |
| US20120111572A1 (en) * | 2010-11-09 | 2012-05-10 | Cargol Jr Patrick Michael | Emergency control system for subsea blowout preventer |
| GB2488812A (en) * | 2011-03-09 | 2012-09-12 | Subsea 7 Ltd | Subsea dual pump system with automatic selective control |
| RU2469177C2 (en) * | 2007-06-01 | 2012-12-10 | Фмс Конгсберг Сабси Ас | Control method of lubricant injection, and lubricant injector |
| WO2014147406A3 (en) * | 2013-03-21 | 2014-12-31 | Geoprober Drilling Limited | Subsea hydraulic power generation |
| US9822600B2 (en) * | 2012-11-07 | 2017-11-21 | Transocean Sedco Forex Ventures Limited | Subsea energy storage for well control equipment |
| CN107532467A (en) * | 2015-05-01 | 2018-01-02 | 海德里尔美国配送有限责任公司 | Hydraulic pressure for deep-water blowout preventer is reconfigurable and the repairable control system in seabed |
| CN108625822A (en) * | 2018-05-08 | 2018-10-09 | 海峰深水（天津）技术服务有限公司 | Multistage sequentially triggered emergency system capable of automatically shearing tubular column and sealing well |
| WO2021048181A1 (en) * | 2019-09-09 | 2021-03-18 | Fmc Kongsberg Subsea As | A subsea deployable installation and workover control system skid and method of installation thereof |
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1985
- 1985-01-21 CA CA000472499A patent/CA1239090A/en not_active Expired
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2445506A (en) * | 2005-10-19 | 2008-07-09 | Cooper Cameron Corp | Subsea equipment |
| GB2445506B (en) * | 2005-10-19 | 2010-02-10 | Cooper Cameron Corp | Subsea equipment |
| WO2007045260A1 (en) * | 2005-10-19 | 2007-04-26 | Cooper Cameron Corporation | Subsea equipment |
| RU2469177C2 (en) * | 2007-06-01 | 2012-12-10 | Фмс Конгсберг Сабси Ас | Control method of lubricant injection, and lubricant injector |
| US20120111572A1 (en) * | 2010-11-09 | 2012-05-10 | Cargol Jr Patrick Michael | Emergency control system for subsea blowout preventer |
| WO2012064812A3 (en) * | 2010-11-09 | 2012-07-05 | Wild Well Control, Inc. | Emergency control system for subsea blowout preventer |
| US9234400B2 (en) | 2011-03-09 | 2016-01-12 | Subsea 7 Limited | Subsea pump system |
| RU2598953C2 (en) * | 2011-03-09 | 2016-10-10 | Сабси 7 Лимитед | Pumping system |
| WO2012120307A3 (en) * | 2011-03-09 | 2013-03-21 | Subsea 7 Limited | Pump system |
| WO2012120307A2 (en) | 2011-03-09 | 2012-09-13 | Subsea 7 Limited | Pump system |
| GB2488812A (en) * | 2011-03-09 | 2012-09-12 | Subsea 7 Ltd | Subsea dual pump system with automatic selective control |
| US20200157906A1 (en) * | 2012-11-07 | 2020-05-21 | Transcoean Sedco Forex Ventures Limited | Subsea energy storage for blow out preventers (bop) |
| US9822600B2 (en) * | 2012-11-07 | 2017-11-21 | Transocean Sedco Forex Ventures Limited | Subsea energy storage for well control equipment |
| US10316605B2 (en) | 2012-11-07 | 2019-06-11 | Transocean Sedco Forex Ventures Limited | Subsea energy storage for well control equipment |
| US11060372B2 (en) * | 2012-11-07 | 2021-07-13 | 1169997 Ontario Ltd. Operating As Aspin Kemp & Associates | Subsea energy storage for blow out preventers (BOP) |
| WO2014147406A3 (en) * | 2013-03-21 | 2014-12-31 | Geoprober Drilling Limited | Subsea hydraulic power generation |
| CN107532467A (en) * | 2015-05-01 | 2018-01-02 | 海德里尔美国配送有限责任公司 | Hydraulic pressure for deep-water blowout preventer is reconfigurable and the repairable control system in seabed |
| CN108625822A (en) * | 2018-05-08 | 2018-10-09 | 海峰深水（天津）技术服务有限公司 | Multistage sequentially triggered emergency system capable of automatically shearing tubular column and sealing well |
| CN108625822B (en) * | 2018-05-08 | 2024-04-02 | 海一峰深水（天津）技术服务有限公司 | Multistage sequential triggering emergency system capable of automatically shearing tubular column and sealing well hole |
| WO2021048181A1 (en) * | 2019-09-09 | 2021-03-18 | Fmc Kongsberg Subsea As | A subsea deployable installation and workover control system skid and method of installation thereof |
| US11846162B2 (en) | 2019-09-09 | 2023-12-19 | Fmc Kongsberg Subsea As | Subsea deployable installation and workover control system skid and method of installation thereof |
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