Solenoid valve housings for blowout preventer

This application claims priority to provisional application 62/093,083, filed Dec. 17, 2014.

This applications relates in general to blowout preventers for subsea well drilling, and in particular to a control system for a blowout preventer, the control system having solenoid valve housings that can be separately drained of dielectric fluid for maintenance.

Offshore drilling operations require a blowout preventer connected with the drilling riser to control well pressure. A typical subsea blowout preventer (“BOP”) has many components, such as one or more annular blowout preventers, several pipe rams, connectors for connecting to wellhead equipment, and a quick release connector for releasing an upper portion of the BOP and the drilling riser from a lower portion in the event of an emergency. Most of these components, also referred to as functions, are hydraulically actuated.

The BOP has a control system, also referred to as a multiplex or MUX pod layout, to control these various functions by supplying hydraulic fluid pressure to perform the particular function. The control system has hydraulic valves, called SPM (sub plate manifold) valves, that supply hydraulic fluid pressure to the various BOP components. The control system has solenoid valves, that when receiving an electrical signal, send a hydraulic pilot signal to one of the hydraulic valves.

Several of the solenoid valves may be mounted in a solenoid valve housing that is filled with an electrically insulating dielectric liquid. A typical control system will have several solenoid valve housings. Each solenoid valve housing may have a pressure compensator to equalize the dielectric liquid pressure with the hydrostatic pressure of the sea water.

Current practice requires all of the solenoid housings to be drained of dielectric fluid any time a component located in one of the solenoid housings needs to be serviced. The total volume of dielectric fluid in the control system can exceed 80 gallons. As a result, a large quantity dielectric fluid is lost and must be replaced each time maintenance is required in one of the solenoid valve housings.

A subsea blowout preventer control system has a plurality of solenoid valve housings mounted in at least one vertical column. A plurality of solenoid valves are mounted within each of the solenoid valve housings. The control system has a plurality of hydraulic valves, each of the hydraulic valves being hydraulically connected to and controlled by one of solenoid valves. The control system has a central chamber containing a dielectric liquid. A separate communication tube for each solenoid valve housing communicates the dielectric liquid in the central chamber with the interior of the solenoid valve housing. Each of the communication tubes has an open lower end in one of the solenoid valve housings and an open upper end within the central chamber that is at an elevation at least equal to an upper end of the vertical column of valve housings. A separate drain line mounted to each of the solenoid valve housings enables draining of one of the solenoid valve housings for maintenance while the control system is retrieved without requiring draining of the other solenoid valve housings.

In one embodiment, a pressure compensator within the central chamber equalizes a pressure of the dielectric liquid within the central chamber and in all of the solenoid valve housings with a hydrostatic pressure of sea water surrounding the system.

A separate air vent line extends from each of the solenoid valve housings. An air vent valve connects to each of the air vent lines.

In one example, the open upper ends of each of the communication tubes are at substantially the same elevation within the central chamber. The central chamber extends vertically alongside the solenoid valve housings. An electrical wire extends from within the central chamber sealingly through a wall of the central chamber and sealingly through a wall of each of the solenoid valve housings to one of the solenoid valves within said each of the solenoid valve housings.

In the embodiment shown, each of the solenoid valve housings has a horizontal lower side and a horizontal upper side. The open lower end of each of the communication tubes is nearer to the lower side than to the upper side. Each of the communication tubes has a vertical portion within the central chamber, the vertical portions being parallel with each other.

So that the manner in which the features, advantages and objects of the disclosure, as well as others which will become apparent, are attained and can be understood in more detail, more particular description of the disclosure briefly summarized above may be had by reference to the embodiment thereof which is illustrated in the appended drawings, which drawings form a part of this specification. It is to be noted, however, that the drawings illustrate only a preferred embodiment of the disclosure and are therefore not to be considered limiting of its scope as the disclosure may admit to other equally effective embodiments.

FIG. 1 is a partial front schematic view of a blowout preventer control system in accordance with this disclosure, showing the cover plate of one of the solenoid valve housings partially broken out.

FIG. 2 is a schematic front view of one of the solenoid valve housings and part of the central chamber of FIG. 1 with the front covers removed.

The methods and systems of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The methods and systems of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout.

FIG. 1 schematically illustrates an upper part of a control system 11 for a subsea blowout preventer (not shown). The subsea blowout preventer (“BOP”) has many components, such as one or more annular blowout preventers, several pipe rams, connectors for connecting to wellhead equipment, and a quick release connector for releasing an upper portion of the BOP and a riser from a lower portion in the event of an emergency. Most of these components, also referred as functions, are hydraulically actuated. Control system 11 , also referred to as a multiplex or MUX pod layout, is mounted to the BOP and controls these various functions by supplying hydraulic fluid pressure to perform the particular function.

Control system 11 includes a supporting frame 13 , which may be of various configurations. A central housing or chamber 15 mounts to frame 13 . Central chamber 15 is elongated with a length that extends vertically along frame 13 . In the example shown, central chamber 15 is rectangular, having two vertical side walls 17 that are parallel with each other. Central chamber 15 has an upper end 19 and a lower end (not shown) that may be perpendicular to side walls 17 . A conventional dielectric liquid 21 with electrical insulating properties fills the interior of central chamber 15 .

In this embodiment, one or more (two shown) pressure compensators 23 are located in central chamber 15 . Each pressure compensator 23 is conventional and may have various configurations. Each pressure compensator 23 has a movable barrier, such as a piston, bellows, or diaphragm, or a combination thereof, that has one side exposed to sea water pressure and another side exposed to dielectric liquid 21 . The hydrostatic pressure of the sea water causes the barrier to move to equalize the pressure of dielectric liquid with the hydrostatic pressure, or at least reduce a pressure differential.

The interior of central chamber 15 may be divided into two separate cavities sealed from each other, each containing dielectric liquid 21 . One of the pressure compensators 23 may be located in one of the cavities, and the other in the other cavity.

Central chamber 15 is adjacent two vertical columns 25 (one shown) of control system 11 , each adjacent vertical side wall 17 . Solenoid valve housings 27 are secured to frame 13 , one above the other, in each vertical column 25 . In the example, FIG. 1 shows only two solenoid valve housings 27 in each column 25 . Normally, there will be several more solenoid valve housings 27 in each column 25 .

Each solenoid valve housing 27 is generally rectangular and oriented with its length horizontal. Each solenoid valve housing 27 has a flat upper side 29 that is parallel and spaced above a flat lower side 31 . Vertical end walls 33 join opposite ends of the upper and lower sides 29 , 31 to each other. Vertical end walls 33 are parallel to central chamber side walls 17 . An inner one of the vertical end walls 33 is closely spaced to one of the central chamber side wall 17 . Each solenoid valve housing 27 has a removable cover plate 35 on its front side secured by fasteners.

Several solenoid valves 37 mount within each solenoid valve housing 27 to lower side 31 . As an example, the drawings shows five of the solenoid valves 37 , but the number could vary, such as six to eight. Each solenoid valve 37 may be a conventional electrically actuated valve that sends a hydraulic pilot signal upon received of an electrical control signal.

A row 39 of hydraulic valves 41 mounts to frame 13 below each solenoid valve housing 27 . Hydraulic valves 41 are conventional and often referred to as SPM or sub plate manifold valves. In this example, each row 39 is horizontal and located directly below one of the solenoid housings 27 . Each hydraulic valve row 39 thus alternates with one of the solenoid valve housings 27 in each vertical column 25 . When signaled by a pilot signal from one of the solenoid valves 37 , each hydraulic valve 41 supplies or receives hydraulic fluid under pressure to perform one of the BOP functions. Each solenoid valve 37 hydraulically connects to one of the hydraulic valves 41 .

Two subsea electronics modules 43 (only one shown) mount to frame 13 . Each subsea electronics module 43 houses electronics for supplying electrical signals to the various solenoid valves 37 . Normally, the interior of each subsea electronics module 43 will be at one atmosphere pressure while subsea, not pressure compensated. Subsea electronics modules 43 are redundant with each other.

Solenoid valves 37 and hydraulic valves 41 within one of the columns 25 are typically redundant with solenoid valves 37 and hydraulic valves 41 in another column 25 . One of the chambers or cavities of central chamber 15 may supply dielectric liquid 21 to solenoid valve housings 27 in one of the columns 25 , and the other to the other solenoid valve housings 26 in the other column 25 .

FIG. 2 schematically illustrates one of the solenoid valve housings 27 , with the others being the same. Cover plate 35 ( FIG. 1 ) has been removed as well as the front wall of central chamber 15 . A separate communication tube 47 extends between each solenoid valve housing 27 and central chamber 15 . Each communication tube 47 has a lower portion that extends sealingly through one of the central chamber side walls 17 and sealingly through one of the solenoid housing end walls 33 . The lower portion of each communication tube 47 terminates in one of the solenoid valve housings 27 with an open lower end 49 that is near solenoid housing lower side 31 and near one of the end walls 33 .

Each communication tube 47 has an open upper end 51 that is located above its lower end 49 and at an elevation above the solenoid valve housing 27 containing its open lower end 49 . Preferably, open upper end 51 of each communication tube 47 is at an elevation above the upper side 29 of the uppermost solenoid valve housing 27 in the vertical columns 25 a , 25 b . The open upper ends 51 may be a short distance below central chamber upper end 19 . As illustrated in FIG. 1 , the open upper end 51 may be at the same elevation as the open upper ends 51 of the other communication tubes 47 .

Each communication tube 47 has a vertical portion 47 a extending between its open lower end 49 and open upper end 51 . Vertical portions 47 a are parallel with each other. The vertical portion 47 a of communication tubes 47 extending from lower ones of the solenoid valve housings 27 are longer than vertical portions 47 a of communication tubes 47 extending from upper ones of the solenoid valve housings 27 . During operation, open upper ends 51 will be below the upper level of dielectric liquid 21 in central chamber 15 , which will be at central chamber upper end 19 . Dielectric liquid 21 in central chamber 15 communicates with dielectric liquid filling each solenoid valve housing 27 via each communication tube 47 .

Referring again to FIG. 2 , each solenoid valve housing 27 has a separate drain line 53 to drain dielectric liquid 21 when maintenance to one or more of the solenoid valves 37 therein is needed. In the example, each drain line 53 is located nearer to solenoid valve housing lower side 31 than upper side 29 . Drain line 53 is illustrated tube through the outer one of the end walls 33 , but it could be located elsewhere. A valve 55 , normally manually operated, selectively opens and closes drain line 53 .

A separate vent line 57 for each solenoid valve housing 27 assists in draining and filling. Vent line 57 extends from an upper portion of each solenoid valve housing 27 near upper side 29 . FIG. 2 illustrates vent line 57 as extending sealingly through the inner end wall 33 and central chamber side wall 17 , then out central chamber upper end 19 . The vent lines 57 for all of the solenoid valve housings 27 could similarly extend through central chamber upper end 19 . Alternately, each vent line 57 could extend directly from each solenoid valve housing 27 and not pass through the inferior of central chamber 15 . A vent line valve 59 , which may be manually operable, selectively opens and closes each vent line 57 . The cavities of pressure compensators 23 may have a similar vent line (not shown) at upper end 19 .

Referring still to FIG. 2 , a signal line 61 , which may be electrical, extends sealingly into each solenoid valve housing 27 . Signal line 61 may include separate electrical wires connected to each solenoid valve 37 within a particular solenoid valve housing 27 . In this example, a penetrator connector 63 for signal line 61 extends sealingly through apertures in central chamber side wall 17 and in one of the end walls 33 of each solenoid valve housing 27 . Signal line 61 extends to the base of subsea electronics modules 43 for communication with circuitry in one of the subsea electronics modules 43 . For clarity, FIG. 1 does not show drain lines 53 , vent lines 57 and signal lines 61 .

During an initial installation of control system 11 , technicians fill dielectric liquid 21 into central chamber 15 and solenoid valve housings 27 prior to lowering the BOP subsea. The filling may be performed in different manners. For example, the technician may pump dielectric liquid 21 through a lower inlet (not shown) in central chamber 15 while drain line valves 55 are closed and vent line valves 59 are open. Once the dielectric liquid reaches communication tube upper ends 51 , it flows down communication tubes 47 into solenoid valve housings 27 to fill them. Once central chamber 15 and all of the solenoid valve housings 27 are full and trapped air is expelled, the technician closes vent line valves 59 .

The operator on a drilling and/or production vessel then lowers the BOP along with control system 11 into the sea. The hydrostatic pressure of the sea will cause pressure compensators 23 to equalize the pressure of dielectric liquid 21 within central chamber 15 and solenoid valve housings 27 with she hydrostatic pressure. The increase in pressure in dielectric liquid 21 in central chamber 15 communicates with the dielectric liquid in each solenoid valve housing 27 via the communication tubes 47 , which always remain open. In this example, pressure compensators 23 equalize pressure for solenoid valve housings 27 as well as central chamber 15 . Alternately, solenoid valve housings 27 could have their own pressure compensators.

During operation, hydraulic valves 41 will be connected with a hydraulic fluid source, typically via subsea accumulators and a conduit extending to the drilling rig. When a function is desired, the operator at the rig supplies an electrical signal via an umbilical line to one or both subsea electronics modules 43 . In turn, circuitry in subsea electronics module 43 sends a signal, normally electrical, through signal line 61 to one of the solenoid valves 37 . In response, the solenoid valve 37 provides a hydraulic pilot signal to the hydraulic valve 41 that is linked. In response, the hydraulic valve 41 receiving the pilot signal supplies hydraulic fluid to the selected component of the BOP or receives hydraulic fluid from the selected component.

Any maintenance or replacement of any of the solenoid valves 37 will be performed while the BOP and control system 11 are retrieval. Normally, the operator will have determined which one of the solenoid valves 37 requires repair or replacement. A technician will drain the dielectric liquid 21 contained in only the solenoid valve housing 27 or housings 27 requiring maintenance. The operator opens the particular drain line valve 55 and vent line valve 59 , allowing dielectric liquid 21 in the particular solenoid valve housing 27 to drain. Because the drain line valves 55 of the other solenoid valve housings 27 are still closed, they will not drain. Similarly, the drain line (not shown) of central chamber 15 remains closed. A small amount of dielectric liquid 21 in central chamber 15 may flow down the open upper end 51 of the communication tube 47 of the particular solenoid valve housing 27 being drained. However, once the level of dielectric liquid 21 within central chamber 15 drops below open upper ends 51 , the flow of dielectric liquid down the communication tube 47 will cease. In this manner, draining even a lowermost one of the solenoid valve housings 27 can occur while keeping the remaining solenoid valve housings 27 , including those at higher elevations, full of dielectric liquid 21 .

After the draining has been completed, the operator may open cover plate 35 and replace or repair the desired solenoid valves 37 . The operator may refill the particular solenoid valve housing 27 by closing the drain line valve 55 and pumping dielectric liquid 21 into a lower portion of central chamber 15 . The dielectric liquid 21 rises above the open upper ends 51 , then flows downward through the particular communication tube 47 into the particular solenoid valve housing 27 requiring filling. Once full and trapped air has been expelled, the technician closes the particular vent line 59 . The operator may then re-deploy the control system 11 .

Because only the affected solenoid valve housing or housings 27 need to be drained, a large amount of dielectric fluid 21 in control system 13 will be saved. For example, control system 11 may contain a total of 80 gallons or more of dielectric fluid 21 , while a single solenoid valve housing 27 contains only 5 gallons. Also, using only the pressure compensator or compensators 23 within central chamber 15 to equalize pressure in all of the solenoid valve housings 27 in one of the columns 25 reduces the cost required if each solenoid valve housing 27 had its own separate pressure compensator.

It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.