CA1239091A - Blowout preventer valve and bop stack - Google Patents
Blowout preventer valve and bop stackInfo
- Publication number
- CA1239091A CA1239091A CA000472500A CA472500A CA1239091A CA 1239091 A CA1239091 A CA 1239091A CA 000472500 A CA000472500 A CA 000472500A CA 472500 A CA472500 A CA 472500A CA 1239091 A CA1239091 A CA 1239091A
- Authority
- CA
- Canada
- Prior art keywords
- blowout preventer
- valve
- segments
- well
- cylindrical body
- 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 description 39
- 238000007789 sealing Methods 0.000 claims description 7
- 238000003780 insertion Methods 0.000 claims description 2
- 230000037431 insertion Effects 0.000 claims description 2
- 230000002093 peripheral effect Effects 0.000 claims description 2
- 230000000717 retained effect Effects 0.000 claims description 2
- 239000000306 component Substances 0.000 abstract 1
- 238000005553 drilling Methods 0.000 description 9
- 241000387514 Waldo Species 0.000 description 6
- 238000012856 packing Methods 0.000 description 6
- 239000003129 oil well Substances 0.000 description 5
- 241000191291 Abies alba Species 0.000 description 3
- 235000004507 Abies alba Nutrition 0.000 description 3
- 230000002265 prevention Effects 0.000 description 3
- 238000010008 shearing Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 241000282472 Canis lupus familiaris Species 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 210000002445 nipple Anatomy 0.000 description 1
- 239000002674 ointment Substances 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- E21B34/00—Valve arrangements for boreholes or wells
- E21B34/02—Valve arrangements for boreholes or wells in well heads
- E21B34/04—Valve arrangements for boreholes or wells in well heads in underwater well heads
-
- 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
-
- 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
- E21B33/06—Blow-out preventers, i.e. apparatus closing around a drill pipe, e.g. annular blow-out preventers
- E21B33/061—Ram-type blow-out preventers, e.g. with pivoting rams
-
- 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
- E21B33/06—Blow-out preventers, i.e. apparatus closing around a drill pipe, e.g. annular blow-out preventers
- E21B33/064—Blow-out preventers, i.e. apparatus closing around a drill pipe, e.g. annular blow-out preventers specially adapted for underwater 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 A novel blowout preventer valve is provided herein for connection between a riser connector and a wellhead connector of a sub-sea well. The valve includes a generally cylindrical body connectable in a riser string as a replacement for a riser, the generally cylindrical body being provided with an access opening through the wall thereof, the access opening being closed by cover plate. Two segments of a hollow sphere are rotationally mounted within the generally cylind-rical body, each such segment having a driven shaft projecting outwardly from the generally cylindrical body. Positively actuatable means, e.g. a rotary hydraulic actuator, is provided for rotating the segments towards and away from one another between an open position, where there is free access to the borehole of the well, and a closed position, where a sealed closure is provided on the drill pipe. The valve so provided is smaller in size and lighter in weight than conventional BOP valves, and has less assemblege com-ponents.
Description
I AL
The present invention relates generally to oil and gas well drilling operations, and more particularly concerns apparatus useful in controlling and preventing such well blowouts.
In the production of well fluids, e.g. oil and/
or gas, from wells situated at remote locations, erg.
offshore, it has become the practice to employ automatic shutoff valves which are responsive to the pressure of well fluids so as to be actuated from an opened lo condition to a closed condition in the event of loss of well fluids as may be caused by various circumstances.
For example, it may occur that a well located at sea may suffer damage which will allow well fluids to flow into the sea, not only resulting in the loss of well fluids until the well can be killed, but also resulting in contamination of the sea water and the sea shore when oil escapes into the sea and drifts ashore.
During various stages of drilling, production or servicing of an oil well, there are occasions when the pressure in the well is sufficient to force the contents of the well inwardly out of the well, whether the con-tents of the well be oil, drilling mud, completion fluid, or the like. A blowout preventer, or other valve device, is therefore provided for sealing off the well during such intervals. It may be necessary to close one ' d I ~39 AL) ~31 or more blowout preventers and seal off the well while a drill pipe is in the well, while a tubing string is passing through the casing head, or while the well and/
or casing head are otherwise empty.
Various such valves have been heretofore dove-loped for the purpose of automatically shutting off such a flowing well, at a subsurface location in the production pipe string.
Such subsurface shutoff valves are generally held open lo by fluid pressure supplied through control fluid conduits extending into the well from the platform. The use of such valves has heretofore posed problems due to the valves being unreliable and inoperative when needed.
A more reliable means of shutoff at the midline was thought to involve the use of a conventional Christmas tree assembly at the subsurface. The subsurface Christmas tree had been attached to the usual subsurface Waldo equipment and included gate valves having an actuator automatically operable to close the gate valve in an 20 emergency or when desired. However, such subsurface Christmas trees were not susceptible of installation within the well or casing extension, and therefore, were exposed to the hostile underwater environment.
This problem was thought to be solved by a removable subset test tree which was adapted to be located in a blowout preventer stack which had an upper release able latch assembly to permit the drill pipe or other tubular string above the test tree to be released from SUE
the valve portion when the latter was in a closed condition, permitting removal of the tubular string there above and the temporary abandonment of the well in the event that high seas or inclement weather made it necessary, or desirable to do so. More specifically in such allegedly improved structure, one or more valves were placed in an open condition by fluid pressure pumped down a hydraulic control line extending from a drilling vessel to the tree disposed in the blowout preventer stack. The hydraulic lo pressure control line also extended from the drilling vessel to a releasable connection. When pressure was applied through the line, the connection was released.
Other such valves were the automatic choke valves that cut off flow from wells, which were often installed intermediate the ends of the tube strings of producing wells. When some catastrophe or failure of the controls at the well head resulted in the well running wild, the choke valves automatically closed the well down. Often, however the choke valves were destroyed or not installed and then there was a great loss of valuable material compounded by liability for any damage caused by the pollution of the environment by the lost material. In the use of such automatic choke valves at the present time, a plurality of tubing strings, one for each producing well, may be encased in a pipe casing comprising a plurality of concentric metal and cement casings with the tubing strings in the center.
9~9~
The pipe casings were often as large as three feet in diameter and posed a difficult problem to reach a part-ocular tubing string.
Ball valves have also been suggested for use as subsurface safety valves for wells. As is known, ball valves include a hole through the ball with a 90 degree rotation of the ball to change from a fully opened to a fully blocked orientation.
In one such ball valve developed, the ball was I more easily shifted from its closed to its open position by reason of the incorporation in the valve assembly of by-pass or equalizing valve means responsive to the pressure of control fluid to establish communication be-tweet the flow passage at opposite sides of the ball valve before the ball valve is opened. In addition, the ball was supported for rotation by means which allowed slight lost motion between the valve and the support during the first and last stages of ball rotation between open and closed positions, so that the ball support was not subjected to pressure differentials which may load the ball.
An improved such subsurface safety valve of the ball valve type was that provided by DO Hudson in US.
Patent 3,796,257 patented March 12, 1974. That valve included a ball valve closed by well fluid pressure and opened by control fluid pressure supplied from the surface. The subsurface valve included a control fluid pressure responsive balancing valve for equalizing pressure across the closed ball valve to relieve the ,. I .. -I
ball valve seating pressure. The ball valve was rotatable by support pins and was also slightly axially movable in its support. A sealing and operating sleeve below the ball valve was spring loaded upwardly. One or more additional springs were incorporated in a prod-unction tubing string or was removably received in a seating nipple so as to be wire line retrievable.
Yet another such valve was provided by SO
Helms in the US. Patent No. 3,870,101, patented March 11, lo 1975, which included one or more lower ball valves which were pressure actuated to open position from the vessel or platform to permit well testing, and also an upper latch mechanism releasable secured to the valve portion of the assembly. Relieving of the pressure effected closing of one or more valves, permitting the latch mechanism to be released and removed with the paper portion of the tubing or drill pipe string to the vessel or platform. The pistons controlling the valves were pressure balanced, with the valves being adapted to permit reverse flow around them when in closed condition.
A pressure actuated piston capable of forcing a lower ball valve to closed position was provided which, in so doing, cut a wire line which may have parted above the assembly, and which would otherwise hold the ball valve open.
Another valve assembly of the valve type for a subterranean well conduit was that taught in ROY. Brooks US. Patent 4,306,633, patented December 22, _ 5 _ 39()~9~
1981. That valve assembly was carryable between upper and lower portions of a tubular conduit extendible to at least one production zone in the well. The valve assembly comprised first and second ball valve elements interior of the assembly and was shiftable between fully open and fully closed position to the fully open position prior to the other of the valve elements being manipulated from the fully closed position. The ball valve elements were circumferential off-set from one another and lo could be provided in a cartridge-type assembly.
While ball valves were known to perform better with no or least leakage of any flow through pipes, since they had a substantially full bore opening there through and thereby caused no substantial restrict lion to flow, some problems still existed with ball valves. Such ball valves experienced operating dip-- faculties, particularly when they were being opened and the well fluid pressure below the valve which was holding the valve closed was substantially causing a high friction 20 loading between the sealing faces and the surface of the ball with which they were sealingly engaged. Indeed, the operating means for shifting the ball to an open position could in some instances be destroyed thereby rendering the valve inoperative just when it was needed to be operated.
~;~3C~
Consequently another type of well blowout control and prevention equipment was provided which could positively block the entire well passage. Two types of such blowout preventers are thus currently available for oil well blowout prevention and control, namely, an annular preventer, and a ram preventer.
Annular-type preventers are designed to close and seal over an open hole. These type of preventers are also capable of sealing around any cylindrical or lo nearly cylindrical objects. These preventers have an internally reinforced rubber packing ring. The closure can be made on drill collars, tool joints, kelly, tapered drill strings, etc.
Ram type preventers have twin ram closing elements.
These rams can be of the blind/shearing type capable of closing on the drill pipe or casing. For the latter type, two opposing Unshaped rams are brought together by double-acting hydraulically controlled pistons to close on a casing pipe or a drill string.
Typical of such ram-type blowout preventer valves is the assembly provided in GO Lewis et at US. Patent 3,533,468 patented October 13, 1970. In that patent a well blowout preventer assembly was prove idled incorporating a packet constricting actuator which formed with the housing, at least three pressure ; receiving chambers. The chamber received control fluid pressure acting to urge the actuator downwardly for ~:39091 relieving packer constriction. The second chamber received control fluid pressure acting to urge the act-valor upwardly for constricting the packer. The third chamber received controllable balancing pressure acting to urge the actuator upwardly in at least partly counterbalancing relation to the opposite effect of well fluid e.g. drilling mud, the static pressure of which (especially in subset oil well drilling operations) acts via the packer to urge the actuator downwardly.
o Another such valve was the stationary blowout preventer of the J. Reran US. Patent 3,583, 480 patented June 8, 1981 which included a balloon-type packing unit with a central opening therein, and a retrievable packing insert positioned within the opening by the engagement of a lowering with the preventer and release able secured therein by hydraulically releasable dogs fetchingly engaging a latching notch in an upper ring.
A central rubber portion of the packing insert sealingly engaged the pipe tool there through when the packing unit was pressurized by fluid. The blowout preventer had a fluid accumulator which absorbed the surge pressure and excess fluid to maintain a constant pressure on the packing insert as a pipe tool joint was stripped there through to maintain the sealing engagement between the insert and the pipe.
V~3~
Still another such valve was provided by GEE.
Lewis et at in Canadian Patent 910,188 patented September 19, 1972. That patent combined well passage constricting apparatus with safety valve structure. The invention provided an improvement in well blowout prevention apparatus by the combination of housing structure defining vertically spaced intercommunicating chambers. An inwardly constructible packer annuls was disposed in one of such chambers for forming therewith a vertical lo passage through which well tools may be run. An annular piston was movable upwardly in that chamber to constrict the annuls for reducing the opening. A plug stopper having a through opening was mounted to rotate in another of the chambers to bring the through opening into and out of registration with the passage. The housing struck lure included a section at the side of the plug opposite that chamber and which was removable to provide direct access to the plug.
Furthermore, a subsurface or midline shutoff valve assembly was provided in AGO. Ahlstone et at Canadian Patent 965,697 patented April 8, 1975. The patent provided a subsurface shutoff valve assembly, including gate valves incorporated in a body which was affixed to a connector adapted to be run downwardly through the extension casing and landed in the usual subsurface casing hanger. The shutoff valve assembly had a shutoff valve or gate for each producing zone of the well. Tubing was connected between the shutoff , valve assembly and the platform at the top of the water to conduct production fluids to the surface. The shutoff valves or gates were held open by control fluid pressure supplied through control fluid conduits from the platform. When control fluid pressure was bled off for any reason, either purposely to shut in a selected well zone or due to an accident or damage to the plats form or surface equipment, resulting in the loss of control fluid pressure which can maintain the subzero-face or midline valves open, the valves automatically closed.
In spite of these patents, a need still exists for an improved blowout preventer valve. One reason for such need is the sheer mass of the valve body, i.e.
of the order of 16 tons for the body, door assembly and ram assembly. A blowout preventer (BOY) stack is goner-ally comprised of three ram preventers, one blind/
shearing ram preventer and one annular preventer. In addition, the BOY Stack is provided with a kill line and a choke line. All conventional BOY stacks at the present time are provided with these components.
Another problem was that the conventional ram type preventers which operated remotely from surface required a large force for their operation and at the end of their operation resulted, in essence, in a Sims elation of a simple gate valve. Moreover, the operating force was generally increased because it had to act against the excessive well pressure.
Ed I
The main object of the present invention is the provision of a blowout preventer stack, capable of performing all required functions more effectively and more economically, in which all ram type preventers are replaced by novel blowout preventer valves, which are smaller in size and lighter in weight and have less assemblage components.
Another object of this invention is the provision of a subsurface shutoff valve wherein the valve is easy lo to manipulate from the open to the closed position even when opposed to high well fluid pressure.
Yet another object of this invention is to provide such a valve which is rugged, sturdy and yet is of considerably less weight thaw those of the prior art.
This invention provides a blowout preventer valve for connection between a riser connector and a Waldo connector of a subset well, the valve coup-rising: a generally cylindrical body connectable in a 20 riser string as a replacement for a riser, the generally cylindrical body being provided with an access opening through one wall thereof, the access opening being closed by a cover plate; two segments of a hollow sphere rotationally mounted within the generally cylindrical body each segment having a driven shaft projecting outwardly from the generally cylindrical . 11 -body; and positively actuatable means for rotating the segments towards and away from one another between an open position, where there is free access to the bore hole of the well, and a closed position, where a sealed closure is provided on the drill pipe.
By one feature of the blowout preventer valve, the two spherical segments share a common center of rotation.
By another feature of the blowout preventer valve lo each spherical segment, is identical, and comprises a bored shaft at one end thereof, and a driven shaft at the diametrically opposite end thereof, each driven shaft of one such segment being fitted within an associated bored shaft of the other segment.
By yet another feature of the blowout preventer valve the segments are adapted to rotate in opposite directions to close downstream of the actuation site, whereby well pressure assists in closing and sealing the segments together.
By yet another feature of the blowout preventer valve, the means to rotate each of the segments towards and away from each other comprises a rotary hydraulic actuator, each rotary hydraulic actuator being connected to an associated driven shaft of the segment.
By still another feature of the blowout preventer valve, the blowout preventer valve includes a solenoid- ¦
rival ring seal assembly to seal flow of fluids between the sealed segments and the generally cylindrical body.
By a further feature of the blowout preventer valve, the blowout preventer valve includes a suitable flange connected to each flat face of the generally cylindrical body.
By still another feature of the blowout prey-enter valve, the blowout preventer valve includes a cylindrical seal assembly to seal flow of fluids between the sealed segments and the generally cylindrical body, the cylindrical seal being located along the inner lo face of the flange.
By another feature of the blowout preventer valve, the blowout preventer valve includes a radial seal along the respective faces of the segments that are adapted to touch one another, thereby to provide a pressure-tight boundary there between when the segments close on one another.
By yet another feature of the blowout preventer valve, the blowout preventer valve includes a peripheral seal around the cover plate to provide a pressure-tight seal between the generally cylindrical body and the cover plate.
By still another feature of the blowout preventer valves, the blowout preventer valve includes seals around the shafts to provide a pressure tight shaft seal, the shaft seals being retained in position by a seal-retaining plate.
- 13 - `
39(~
This invention also provides a blowout preventer stack for insertion in a Swiss well between a riser connection and a Waldo connection, the stack comprising a plurality, e.g. four, interconnected blowout preventer valves as described above.
This invention also provides a closed loop subset system having a source of command electrical energy, and two identical hydraulic control units operable independently but individually, and each comprising a lo main microprocessor controller, and electric motor open-cling a hydraulic pump drawing hydraulic fluid from sub sea diaphragm reservoir and/or hydraulic accumulator, to a solenoid valve module which directs controlled amounts and pressures of hydraulic fluid to a selected hydraulic actuator.
The essence of the present invention is that the actual valve elements are segments of a hollow sphere assembled together. To oppose the flow to be obstructed, rotary actuators are used to bring the segments towards each other to close and the obstructed flow pressure assists in complete closure of the segments. Constant obstructed flow pressure keeps the segments locked.
In the accompanying drawings, Figure 1 it a schematic elevation Al view show-in a floating offshore drill ship with the blowout prey-enter of an embodiment of this invention installed in a sub-sea Waldo assembly;
Figure 2 is a plan view of the blowout preventer valve assembly of one aspect of this invention;
Figure 3 is a front elevation Al view thereof;
Figure 4 is a side elevation Al view thereof;
Figure 5 is a plan sectional view thereof, with the valve in the open condition;
Figure 6 is a front sectional view thereof, with the valve in the open condition;
Figure 7 is a side view thereof, with the valve lo in the open condition;
Figure 8 is a partial front view of the valve in its closed condition; and Figure 9 is a schematic elevation Al view of a closed loop subset control system and BOY Stack of an embodiment of this invention.
Figure 1 merely shows an offshore floating drill lying unit A provided with the usual accouterments for subset drilling B extending via drill string C to a subset well D provided with a blowout preventer stack E
of embodiments of this invention, now to be described.
As seen in Figures 2 - 8, the blowout preventer valve 10 comprises a generally cylindrical body 11 in the form of a pair of generally semi-cylindrical come pennants 12, each having a rounded face 13, a flat face 14 and a terminal stub 15. The top and bottom faces 16, 17 are each provided with suitable internal flange 18, e.g. an API-type 6BX flange capable of 15,000 psi I
working pressure. By means of this flange, which is common to the oil well drilling industry, the blowout preventer body may be connected to existing oil well drill equipment. Thus, the body 11 ends with such APT-type internal flanges.
As shown, the flange 18 is provided with a plurality of circumferential spaced apart connecting apertures, 19 for connection to an adjacent such flange 18 by bolts 20.
lo Within body 11 is the novel valve element in the form of a pair of identical spherical segments 21, 22. Each segment 21 or 22, has a bored shaft 23, 24 and a driven shaft 25, 26. The segments are inter-connected so that driven shaft 25 of the segment 21 is rotatable mounted in bored shaft 24 of segment 22, and driven shaft 26 of segment 22 is rotatable mounted in bored shaft 23 of segment 21. In this way, the axes of rotation 27 of both segments are the same.
Shaft 26 is sealed in a pressure tight manner at aperture 28 within terminal stub 15 of body 11 by means of an encircling shaft seal 29, held in place by an annular seal-retaining plate 30.
The space or opening 31 between the ends 32 of the flat faces 14 is sealed by a cover plate 33, held in place by cover plate bolts 34 fitted in tapped holes 35 in the respective ends 31, 32. This cover plate 33, located on the side of the blowout preventer body, closes ;39~
or covers the opening 31 used to install and remove the two segments 21, 22 and a circular seal (to be described hereinafter).
A pressure-tight seal is provided by annular cover plate seal 36 disposed at the periphery 37 of the cover plate 33. The cover plate 33 is also provided with an aperture 38 through which shaft 25 passes.
Shaft 25 is sealed in a pressure-tight manner at aperture 38 by means of an encircling shaft seal 39 held in place lo by an annular seal-retaining plate 40. The cover plate 33 is also provided with a countersunk portion 41, to accommodate bored shaft 24, and internal spherical faces 42, to mate with the spherical faces of spherical segments 21, 22, Rotation of the segments 21, 22 is by rotation of driven shafts 25, 26 connected to the output shafts of rotary actuators 43, 44. The rotary actuator may be that known by the trade mark FLO-TORK INC., Ohio. It is preferred to use FLO-TORK Model 600,000 providing from 100,000 pound-inches output torque at 500 psi input pressure to 600,000 pound-inches output torque at 3000 psi input pressure.
The flat opposed faces 45, 46 of the spherical segments 21, 22 are provided with segment seals 47, 48.
The segment seals are each provided with drill pipe notch . portions 49. A ring seal assembly 50 is disposed at the internal downstream face of the body 11 at the internal flange 18.
In operation, the closing function is achieved by rotating the two segments 21, 22 in such a manner that they come together to form a seal or closure on the drill pipe. These segments 21, 22 have been cut out of a hollow sphere and share a common center of rotation.
As described above, each segment 21, 22 has a radially located seal 47, 48 along the face that comes in contact with the opposite or opposing segment. As the two - segments 21, 22 rotate towards each other and touch, 0 the seals 47, 48 contact each other to form a pressure-tight boundary. A ring seal 50, circular in shape seals the flow of fluids between the segments 21, 22 and the body 11 that contains the two segments 21, 22.
It is seen therefore that the segmented hollow split ball valve closes by rotation of its segments across the flow path of the fluids in the well, downstream of the actuation or rotation axis. Thus, the pressure of the well fluids tends to close the segmented hollow split ball valve, and to maintain the valve sealed.
Figure 9 shows a closed loop subset control system and BOY stack. The subset Waldo includes the conventional annular preventer and ball joint 101 and riser connector 102 as well as lower Waldo connector 103. Disposed there between are four split ball blowout preventer valves according to this invention. The three lower such valves, 104, each operate as a blowout preventer valve. The fourth such valve, 105, operates as a shearing blowout preventer/valve.
I R
The control system shown in Figure 9 includes an uninterrupted power supply (UPS.) 110 supplied from the rig power supply. A microprocessor 111 drawing from the UPS. 110 receives data from a logging terminal 112, a driller's display control panel 113 and a remote display control panel 114 and feeds information to a communications and power junction box 115. Commands are given from box 115 to a primary (or yellow) pod 116 and to a secondary, standby (or blue) pod 126. The lo electric commands to a cable 117 wound on an electric cable tensioning reel 118 feeds to a control micro-processor 119.
Pod 126 is a secondary or "back-up" system.
The components thereof while not being numbered, are identical in structure and operation to those same numbered components of the primary pod 116.
To operate the hydraulic rotary actuator of the blowout preventer valve, a motor 120 operates a hydraulic pump 121, which draws hydraulic fluid from a diaphragm reservoir 122 and/or a hydraulic accumulator - 123 to a solenoid valve module 124. This sends hydraulic fluid through protected lines 125 to the hydraulic rotary actuator.
Should failure occur in the primary electrical circuit, control signals go to the back up pod 126.
:
The present invention relates generally to oil and gas well drilling operations, and more particularly concerns apparatus useful in controlling and preventing such well blowouts.
In the production of well fluids, e.g. oil and/
or gas, from wells situated at remote locations, erg.
offshore, it has become the practice to employ automatic shutoff valves which are responsive to the pressure of well fluids so as to be actuated from an opened lo condition to a closed condition in the event of loss of well fluids as may be caused by various circumstances.
For example, it may occur that a well located at sea may suffer damage which will allow well fluids to flow into the sea, not only resulting in the loss of well fluids until the well can be killed, but also resulting in contamination of the sea water and the sea shore when oil escapes into the sea and drifts ashore.
During various stages of drilling, production or servicing of an oil well, there are occasions when the pressure in the well is sufficient to force the contents of the well inwardly out of the well, whether the con-tents of the well be oil, drilling mud, completion fluid, or the like. A blowout preventer, or other valve device, is therefore provided for sealing off the well during such intervals. It may be necessary to close one ' d I ~39 AL) ~31 or more blowout preventers and seal off the well while a drill pipe is in the well, while a tubing string is passing through the casing head, or while the well and/
or casing head are otherwise empty.
Various such valves have been heretofore dove-loped for the purpose of automatically shutting off such a flowing well, at a subsurface location in the production pipe string.
Such subsurface shutoff valves are generally held open lo by fluid pressure supplied through control fluid conduits extending into the well from the platform. The use of such valves has heretofore posed problems due to the valves being unreliable and inoperative when needed.
A more reliable means of shutoff at the midline was thought to involve the use of a conventional Christmas tree assembly at the subsurface. The subsurface Christmas tree had been attached to the usual subsurface Waldo equipment and included gate valves having an actuator automatically operable to close the gate valve in an 20 emergency or when desired. However, such subsurface Christmas trees were not susceptible of installation within the well or casing extension, and therefore, were exposed to the hostile underwater environment.
This problem was thought to be solved by a removable subset test tree which was adapted to be located in a blowout preventer stack which had an upper release able latch assembly to permit the drill pipe or other tubular string above the test tree to be released from SUE
the valve portion when the latter was in a closed condition, permitting removal of the tubular string there above and the temporary abandonment of the well in the event that high seas or inclement weather made it necessary, or desirable to do so. More specifically in such allegedly improved structure, one or more valves were placed in an open condition by fluid pressure pumped down a hydraulic control line extending from a drilling vessel to the tree disposed in the blowout preventer stack. The hydraulic lo pressure control line also extended from the drilling vessel to a releasable connection. When pressure was applied through the line, the connection was released.
Other such valves were the automatic choke valves that cut off flow from wells, which were often installed intermediate the ends of the tube strings of producing wells. When some catastrophe or failure of the controls at the well head resulted in the well running wild, the choke valves automatically closed the well down. Often, however the choke valves were destroyed or not installed and then there was a great loss of valuable material compounded by liability for any damage caused by the pollution of the environment by the lost material. In the use of such automatic choke valves at the present time, a plurality of tubing strings, one for each producing well, may be encased in a pipe casing comprising a plurality of concentric metal and cement casings with the tubing strings in the center.
9~9~
The pipe casings were often as large as three feet in diameter and posed a difficult problem to reach a part-ocular tubing string.
Ball valves have also been suggested for use as subsurface safety valves for wells. As is known, ball valves include a hole through the ball with a 90 degree rotation of the ball to change from a fully opened to a fully blocked orientation.
In one such ball valve developed, the ball was I more easily shifted from its closed to its open position by reason of the incorporation in the valve assembly of by-pass or equalizing valve means responsive to the pressure of control fluid to establish communication be-tweet the flow passage at opposite sides of the ball valve before the ball valve is opened. In addition, the ball was supported for rotation by means which allowed slight lost motion between the valve and the support during the first and last stages of ball rotation between open and closed positions, so that the ball support was not subjected to pressure differentials which may load the ball.
An improved such subsurface safety valve of the ball valve type was that provided by DO Hudson in US.
Patent 3,796,257 patented March 12, 1974. That valve included a ball valve closed by well fluid pressure and opened by control fluid pressure supplied from the surface. The subsurface valve included a control fluid pressure responsive balancing valve for equalizing pressure across the closed ball valve to relieve the ,. I .. -I
ball valve seating pressure. The ball valve was rotatable by support pins and was also slightly axially movable in its support. A sealing and operating sleeve below the ball valve was spring loaded upwardly. One or more additional springs were incorporated in a prod-unction tubing string or was removably received in a seating nipple so as to be wire line retrievable.
Yet another such valve was provided by SO
Helms in the US. Patent No. 3,870,101, patented March 11, lo 1975, which included one or more lower ball valves which were pressure actuated to open position from the vessel or platform to permit well testing, and also an upper latch mechanism releasable secured to the valve portion of the assembly. Relieving of the pressure effected closing of one or more valves, permitting the latch mechanism to be released and removed with the paper portion of the tubing or drill pipe string to the vessel or platform. The pistons controlling the valves were pressure balanced, with the valves being adapted to permit reverse flow around them when in closed condition.
A pressure actuated piston capable of forcing a lower ball valve to closed position was provided which, in so doing, cut a wire line which may have parted above the assembly, and which would otherwise hold the ball valve open.
Another valve assembly of the valve type for a subterranean well conduit was that taught in ROY. Brooks US. Patent 4,306,633, patented December 22, _ 5 _ 39()~9~
1981. That valve assembly was carryable between upper and lower portions of a tubular conduit extendible to at least one production zone in the well. The valve assembly comprised first and second ball valve elements interior of the assembly and was shiftable between fully open and fully closed position to the fully open position prior to the other of the valve elements being manipulated from the fully closed position. The ball valve elements were circumferential off-set from one another and lo could be provided in a cartridge-type assembly.
While ball valves were known to perform better with no or least leakage of any flow through pipes, since they had a substantially full bore opening there through and thereby caused no substantial restrict lion to flow, some problems still existed with ball valves. Such ball valves experienced operating dip-- faculties, particularly when they were being opened and the well fluid pressure below the valve which was holding the valve closed was substantially causing a high friction 20 loading between the sealing faces and the surface of the ball with which they were sealingly engaged. Indeed, the operating means for shifting the ball to an open position could in some instances be destroyed thereby rendering the valve inoperative just when it was needed to be operated.
~;~3C~
Consequently another type of well blowout control and prevention equipment was provided which could positively block the entire well passage. Two types of such blowout preventers are thus currently available for oil well blowout prevention and control, namely, an annular preventer, and a ram preventer.
Annular-type preventers are designed to close and seal over an open hole. These type of preventers are also capable of sealing around any cylindrical or lo nearly cylindrical objects. These preventers have an internally reinforced rubber packing ring. The closure can be made on drill collars, tool joints, kelly, tapered drill strings, etc.
Ram type preventers have twin ram closing elements.
These rams can be of the blind/shearing type capable of closing on the drill pipe or casing. For the latter type, two opposing Unshaped rams are brought together by double-acting hydraulically controlled pistons to close on a casing pipe or a drill string.
Typical of such ram-type blowout preventer valves is the assembly provided in GO Lewis et at US. Patent 3,533,468 patented October 13, 1970. In that patent a well blowout preventer assembly was prove idled incorporating a packet constricting actuator which formed with the housing, at least three pressure ; receiving chambers. The chamber received control fluid pressure acting to urge the actuator downwardly for ~:39091 relieving packer constriction. The second chamber received control fluid pressure acting to urge the act-valor upwardly for constricting the packer. The third chamber received controllable balancing pressure acting to urge the actuator upwardly in at least partly counterbalancing relation to the opposite effect of well fluid e.g. drilling mud, the static pressure of which (especially in subset oil well drilling operations) acts via the packer to urge the actuator downwardly.
o Another such valve was the stationary blowout preventer of the J. Reran US. Patent 3,583, 480 patented June 8, 1981 which included a balloon-type packing unit with a central opening therein, and a retrievable packing insert positioned within the opening by the engagement of a lowering with the preventer and release able secured therein by hydraulically releasable dogs fetchingly engaging a latching notch in an upper ring.
A central rubber portion of the packing insert sealingly engaged the pipe tool there through when the packing unit was pressurized by fluid. The blowout preventer had a fluid accumulator which absorbed the surge pressure and excess fluid to maintain a constant pressure on the packing insert as a pipe tool joint was stripped there through to maintain the sealing engagement between the insert and the pipe.
V~3~
Still another such valve was provided by GEE.
Lewis et at in Canadian Patent 910,188 patented September 19, 1972. That patent combined well passage constricting apparatus with safety valve structure. The invention provided an improvement in well blowout prevention apparatus by the combination of housing structure defining vertically spaced intercommunicating chambers. An inwardly constructible packer annuls was disposed in one of such chambers for forming therewith a vertical lo passage through which well tools may be run. An annular piston was movable upwardly in that chamber to constrict the annuls for reducing the opening. A plug stopper having a through opening was mounted to rotate in another of the chambers to bring the through opening into and out of registration with the passage. The housing struck lure included a section at the side of the plug opposite that chamber and which was removable to provide direct access to the plug.
Furthermore, a subsurface or midline shutoff valve assembly was provided in AGO. Ahlstone et at Canadian Patent 965,697 patented April 8, 1975. The patent provided a subsurface shutoff valve assembly, including gate valves incorporated in a body which was affixed to a connector adapted to be run downwardly through the extension casing and landed in the usual subsurface casing hanger. The shutoff valve assembly had a shutoff valve or gate for each producing zone of the well. Tubing was connected between the shutoff , valve assembly and the platform at the top of the water to conduct production fluids to the surface. The shutoff valves or gates were held open by control fluid pressure supplied through control fluid conduits from the platform. When control fluid pressure was bled off for any reason, either purposely to shut in a selected well zone or due to an accident or damage to the plats form or surface equipment, resulting in the loss of control fluid pressure which can maintain the subzero-face or midline valves open, the valves automatically closed.
In spite of these patents, a need still exists for an improved blowout preventer valve. One reason for such need is the sheer mass of the valve body, i.e.
of the order of 16 tons for the body, door assembly and ram assembly. A blowout preventer (BOY) stack is goner-ally comprised of three ram preventers, one blind/
shearing ram preventer and one annular preventer. In addition, the BOY Stack is provided with a kill line and a choke line. All conventional BOY stacks at the present time are provided with these components.
Another problem was that the conventional ram type preventers which operated remotely from surface required a large force for their operation and at the end of their operation resulted, in essence, in a Sims elation of a simple gate valve. Moreover, the operating force was generally increased because it had to act against the excessive well pressure.
Ed I
The main object of the present invention is the provision of a blowout preventer stack, capable of performing all required functions more effectively and more economically, in which all ram type preventers are replaced by novel blowout preventer valves, which are smaller in size and lighter in weight and have less assemblage components.
Another object of this invention is the provision of a subsurface shutoff valve wherein the valve is easy lo to manipulate from the open to the closed position even when opposed to high well fluid pressure.
Yet another object of this invention is to provide such a valve which is rugged, sturdy and yet is of considerably less weight thaw those of the prior art.
This invention provides a blowout preventer valve for connection between a riser connector and a Waldo connector of a subset well, the valve coup-rising: a generally cylindrical body connectable in a 20 riser string as a replacement for a riser, the generally cylindrical body being provided with an access opening through one wall thereof, the access opening being closed by a cover plate; two segments of a hollow sphere rotationally mounted within the generally cylindrical body each segment having a driven shaft projecting outwardly from the generally cylindrical . 11 -body; and positively actuatable means for rotating the segments towards and away from one another between an open position, where there is free access to the bore hole of the well, and a closed position, where a sealed closure is provided on the drill pipe.
By one feature of the blowout preventer valve, the two spherical segments share a common center of rotation.
By another feature of the blowout preventer valve lo each spherical segment, is identical, and comprises a bored shaft at one end thereof, and a driven shaft at the diametrically opposite end thereof, each driven shaft of one such segment being fitted within an associated bored shaft of the other segment.
By yet another feature of the blowout preventer valve the segments are adapted to rotate in opposite directions to close downstream of the actuation site, whereby well pressure assists in closing and sealing the segments together.
By yet another feature of the blowout preventer valve, the means to rotate each of the segments towards and away from each other comprises a rotary hydraulic actuator, each rotary hydraulic actuator being connected to an associated driven shaft of the segment.
By still another feature of the blowout preventer valve, the blowout preventer valve includes a solenoid- ¦
rival ring seal assembly to seal flow of fluids between the sealed segments and the generally cylindrical body.
By a further feature of the blowout preventer valve, the blowout preventer valve includes a suitable flange connected to each flat face of the generally cylindrical body.
By still another feature of the blowout prey-enter valve, the blowout preventer valve includes a cylindrical seal assembly to seal flow of fluids between the sealed segments and the generally cylindrical body, the cylindrical seal being located along the inner lo face of the flange.
By another feature of the blowout preventer valve, the blowout preventer valve includes a radial seal along the respective faces of the segments that are adapted to touch one another, thereby to provide a pressure-tight boundary there between when the segments close on one another.
By yet another feature of the blowout preventer valve, the blowout preventer valve includes a peripheral seal around the cover plate to provide a pressure-tight seal between the generally cylindrical body and the cover plate.
By still another feature of the blowout preventer valves, the blowout preventer valve includes seals around the shafts to provide a pressure tight shaft seal, the shaft seals being retained in position by a seal-retaining plate.
- 13 - `
39(~
This invention also provides a blowout preventer stack for insertion in a Swiss well between a riser connection and a Waldo connection, the stack comprising a plurality, e.g. four, interconnected blowout preventer valves as described above.
This invention also provides a closed loop subset system having a source of command electrical energy, and two identical hydraulic control units operable independently but individually, and each comprising a lo main microprocessor controller, and electric motor open-cling a hydraulic pump drawing hydraulic fluid from sub sea diaphragm reservoir and/or hydraulic accumulator, to a solenoid valve module which directs controlled amounts and pressures of hydraulic fluid to a selected hydraulic actuator.
The essence of the present invention is that the actual valve elements are segments of a hollow sphere assembled together. To oppose the flow to be obstructed, rotary actuators are used to bring the segments towards each other to close and the obstructed flow pressure assists in complete closure of the segments. Constant obstructed flow pressure keeps the segments locked.
In the accompanying drawings, Figure 1 it a schematic elevation Al view show-in a floating offshore drill ship with the blowout prey-enter of an embodiment of this invention installed in a sub-sea Waldo assembly;
Figure 2 is a plan view of the blowout preventer valve assembly of one aspect of this invention;
Figure 3 is a front elevation Al view thereof;
Figure 4 is a side elevation Al view thereof;
Figure 5 is a plan sectional view thereof, with the valve in the open condition;
Figure 6 is a front sectional view thereof, with the valve in the open condition;
Figure 7 is a side view thereof, with the valve lo in the open condition;
Figure 8 is a partial front view of the valve in its closed condition; and Figure 9 is a schematic elevation Al view of a closed loop subset control system and BOY Stack of an embodiment of this invention.
Figure 1 merely shows an offshore floating drill lying unit A provided with the usual accouterments for subset drilling B extending via drill string C to a subset well D provided with a blowout preventer stack E
of embodiments of this invention, now to be described.
As seen in Figures 2 - 8, the blowout preventer valve 10 comprises a generally cylindrical body 11 in the form of a pair of generally semi-cylindrical come pennants 12, each having a rounded face 13, a flat face 14 and a terminal stub 15. The top and bottom faces 16, 17 are each provided with suitable internal flange 18, e.g. an API-type 6BX flange capable of 15,000 psi I
working pressure. By means of this flange, which is common to the oil well drilling industry, the blowout preventer body may be connected to existing oil well drill equipment. Thus, the body 11 ends with such APT-type internal flanges.
As shown, the flange 18 is provided with a plurality of circumferential spaced apart connecting apertures, 19 for connection to an adjacent such flange 18 by bolts 20.
lo Within body 11 is the novel valve element in the form of a pair of identical spherical segments 21, 22. Each segment 21 or 22, has a bored shaft 23, 24 and a driven shaft 25, 26. The segments are inter-connected so that driven shaft 25 of the segment 21 is rotatable mounted in bored shaft 24 of segment 22, and driven shaft 26 of segment 22 is rotatable mounted in bored shaft 23 of segment 21. In this way, the axes of rotation 27 of both segments are the same.
Shaft 26 is sealed in a pressure tight manner at aperture 28 within terminal stub 15 of body 11 by means of an encircling shaft seal 29, held in place by an annular seal-retaining plate 30.
The space or opening 31 between the ends 32 of the flat faces 14 is sealed by a cover plate 33, held in place by cover plate bolts 34 fitted in tapped holes 35 in the respective ends 31, 32. This cover plate 33, located on the side of the blowout preventer body, closes ;39~
or covers the opening 31 used to install and remove the two segments 21, 22 and a circular seal (to be described hereinafter).
A pressure-tight seal is provided by annular cover plate seal 36 disposed at the periphery 37 of the cover plate 33. The cover plate 33 is also provided with an aperture 38 through which shaft 25 passes.
Shaft 25 is sealed in a pressure-tight manner at aperture 38 by means of an encircling shaft seal 39 held in place lo by an annular seal-retaining plate 40. The cover plate 33 is also provided with a countersunk portion 41, to accommodate bored shaft 24, and internal spherical faces 42, to mate with the spherical faces of spherical segments 21, 22, Rotation of the segments 21, 22 is by rotation of driven shafts 25, 26 connected to the output shafts of rotary actuators 43, 44. The rotary actuator may be that known by the trade mark FLO-TORK INC., Ohio. It is preferred to use FLO-TORK Model 600,000 providing from 100,000 pound-inches output torque at 500 psi input pressure to 600,000 pound-inches output torque at 3000 psi input pressure.
The flat opposed faces 45, 46 of the spherical segments 21, 22 are provided with segment seals 47, 48.
The segment seals are each provided with drill pipe notch . portions 49. A ring seal assembly 50 is disposed at the internal downstream face of the body 11 at the internal flange 18.
In operation, the closing function is achieved by rotating the two segments 21, 22 in such a manner that they come together to form a seal or closure on the drill pipe. These segments 21, 22 have been cut out of a hollow sphere and share a common center of rotation.
As described above, each segment 21, 22 has a radially located seal 47, 48 along the face that comes in contact with the opposite or opposing segment. As the two - segments 21, 22 rotate towards each other and touch, 0 the seals 47, 48 contact each other to form a pressure-tight boundary. A ring seal 50, circular in shape seals the flow of fluids between the segments 21, 22 and the body 11 that contains the two segments 21, 22.
It is seen therefore that the segmented hollow split ball valve closes by rotation of its segments across the flow path of the fluids in the well, downstream of the actuation or rotation axis. Thus, the pressure of the well fluids tends to close the segmented hollow split ball valve, and to maintain the valve sealed.
Figure 9 shows a closed loop subset control system and BOY stack. The subset Waldo includes the conventional annular preventer and ball joint 101 and riser connector 102 as well as lower Waldo connector 103. Disposed there between are four split ball blowout preventer valves according to this invention. The three lower such valves, 104, each operate as a blowout preventer valve. The fourth such valve, 105, operates as a shearing blowout preventer/valve.
I R
The control system shown in Figure 9 includes an uninterrupted power supply (UPS.) 110 supplied from the rig power supply. A microprocessor 111 drawing from the UPS. 110 receives data from a logging terminal 112, a driller's display control panel 113 and a remote display control panel 114 and feeds information to a communications and power junction box 115. Commands are given from box 115 to a primary (or yellow) pod 116 and to a secondary, standby (or blue) pod 126. The lo electric commands to a cable 117 wound on an electric cable tensioning reel 118 feeds to a control micro-processor 119.
Pod 126 is a secondary or "back-up" system.
The components thereof while not being numbered, are identical in structure and operation to those same numbered components of the primary pod 116.
To operate the hydraulic rotary actuator of the blowout preventer valve, a motor 120 operates a hydraulic pump 121, which draws hydraulic fluid from a diaphragm reservoir 122 and/or a hydraulic accumulator - 123 to a solenoid valve module 124. This sends hydraulic fluid through protected lines 125 to the hydraulic rotary actuator.
Should failure occur in the primary electrical circuit, control signals go to the back up pod 126.
:
Claims (14)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE
DEFINED AS FOLLOWS:
1. A blowout preventer valve for connection between a riser connector and a wellhead con-nector of a subsea well comprising:
a generally cylindrical body connectable in a riser string as a replacement for a riser, said generally cyclindrical body being prov-ided with an access opening through one wall thereof, said access opening being closed by a cover plate;
two segments of a hollow sphere rotationally mounted within said generally cylindrical body, each said segment having a driven shaft project-ing outwardly from said generally cylindrical body;
and positively actuatable means for rotating said segments towards and away from one another between an open position, where there is free access to the borehole of the well, and a closed position, where a sealed closure is provided on the drill pipe.
a generally cylindrical body connectable in a riser string as a replacement for a riser, said generally cyclindrical body being prov-ided with an access opening through one wall thereof, said access opening being closed by a cover plate;
two segments of a hollow sphere rotationally mounted within said generally cylindrical body, each said segment having a driven shaft project-ing outwardly from said generally cylindrical body;
and positively actuatable means for rotating said segments towards and away from one another between an open position, where there is free access to the borehole of the well, and a closed position, where a sealed closure is provided on the drill pipe.
2. The blowout preventer of claim 1 wherein said segments share a common centre of rotation.
3. The blowout preventer valve of claim 2 wherein each spherical-segment is identical, and comprises a bored shaft at one end thereof, and a driven shaft at the diametrically op-posite end thereof, each given shaft of one such segment being fitted within an associated bored shaft of the other segments.
4. The blowout preventer valve of claim 1 wherein said means to rotate said segments towards and away from each other comprises a rotary hydraulic actuator, each rotating hydraulic actuator being connected to an assoc-iated shaft of said segment.
5. The blowout preventer valve of claim 1 including a cylindrical ring seal assembly to seal flow of fluids between the sealed segments and the cylindrical body.
6. The blowout preventer valve of claim 1 including a suitable flange connected to each flat face of the generally cylindrical body.
7. The blowout preventer valve of claim 5 including a cylindrical seal assembly to seal flow of fluids between the sealed spher-ical segments and the cylindrical body located along the inner face of the flange.
8. The blowout preventer valve of claim 1 including radial seals along the respective faces of the segments that are adapted to touch one another, thereby to provide a pressure-tight boundary therebetween.
9. The blowout preventer valve of claim 1 including a peripheral seal around the cover plate to provide a pressure-tight seal between the cylindrical body and the cover plate.
10. The blowout preventer valve of claim 1 including seals around the shafts to provide a pressure-tight shaft seal, said seals being retained in position by a seal-retaining plate.
11. The blowout preventer valve of claim 1 wherein said spherical segments are adapted to rotate in opposite directions to close down-stream of the actuation site, whereby well pressure assists in closing and sealing the segments together.
12. A blowout preventer stack for insertion in a subsea well between a riser connection and a wellhead connection, comprising a plurality of interconnected blowout preventer valves as claimed in claim 1.
13. The blowout preventer stack of claim 11 wherein four such blowout preventer valves as claimed in claim 1 are used.
14. A closed loop subsea control system having a source of command electrical energy, and two identical hydraulic control units, operable independently but individually, and each comprising a main microprocessor controller, an electric motor operating a hydraulic pump drawing hydraulic fluid from a subsea diaphragm reservoir and/or hydraulic accumulator, to a solenoid valve module which directs controlled amounts and pressures of hydraulic fluid to a selected hydraulic actuator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000472500A CA1239091A (en) | 1985-01-21 | 1985-01-21 | Blowout preventer valve and bop stack |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000472500A CA1239091A (en) | 1985-01-21 | 1985-01-21 | Blowout preventer valve and bop stack |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1239091A true CA1239091A (en) | 1988-07-12 |
Family
ID=4129631
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000472500A Expired CA1239091A (en) | 1985-01-21 | 1985-01-21 | Blowout preventer valve and bop stack |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1239091A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2012396794B2 (en) * | 2012-12-14 | 2016-03-10 | Halliburton Energy Services, Inc. | Subsea dummy run elimination assembly and related method utilizing a logging assembly |
| CN108930523A (en) * | 2018-09-06 | 2018-12-04 | 中南勘察基础工程有限公司 | A kind of high-pressure slip-casting aperture abnormity locking device |
| CN114183089A (en) * | 2021-12-14 | 2022-03-15 | 河南能源化工集团研究总院有限公司 | Novel blowout preventer for underground drilling of coal mine |
| CN116181274A (en) * | 2023-03-31 | 2023-05-30 | 中煤科工集团重庆研究院有限公司 | Pressure conduction type four-way blowout preventer for underground coal mine drilling construction |
-
1985
- 1985-01-21 CA CA000472500A patent/CA1239091A/en not_active Expired
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2012396794B2 (en) * | 2012-12-14 | 2016-03-10 | Halliburton Energy Services, Inc. | Subsea dummy run elimination assembly and related method utilizing a logging assembly |
| US9598953B2 (en) | 2012-12-14 | 2017-03-21 | Halliburton Energy Services, Inc. | Subsea dummy run elimination assembly and related method utilizing a logging assembly |
| CN108930523A (en) * | 2018-09-06 | 2018-12-04 | 中南勘察基础工程有限公司 | A kind of high-pressure slip-casting aperture abnormity locking device |
| CN114183089A (en) * | 2021-12-14 | 2022-03-15 | 河南能源化工集团研究总院有限公司 | Novel blowout preventer for underground drilling of coal mine |
| CN114183089B (en) * | 2021-12-14 | 2024-03-12 | 河南能源化工集团研究总院有限公司 | Novel colliery is beaten in pit and is bored blowout preventer |
| CN116181274A (en) * | 2023-03-31 | 2023-05-30 | 中煤科工集团重庆研究院有限公司 | Pressure conduction type four-way blowout preventer for underground coal mine drilling construction |
| CN116181274B (en) * | 2023-03-31 | 2025-07-25 | 中煤科工集团重庆研究院有限公司 | Pressure conduction type four-way blowout preventer for underground coal mine drilling construction |
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