Control module for subsea equipment

A subsea control module for providing control of subsea equipment is provided. The design allows for replacement and retrieval of a subsea control module with a single remotely operated vehicle (“ROV”) deployment from a vessel. The subsea control module can provide distributed electrical and hydraulic control functions via multiple directional control valve modules, multiple pilot valve modules, and a central electronic control module. Each directional control and pilot perform a set of functions so that replacement of a single module does not require disassembly of any other components) or hydraulic connection. Similarly, each pilot valve module can include a set of pilot valves, pressure transducers, solenoids and electronic circuitry to perform a limited set of functions so that failure of a single pilot valve module does not result in failure of the entire subsea control module. The central electronic control module can provide electrical signals to each pilot valve module which can provide hydraulic signals to each directional control valve module and to off-board hydraulics through a subsea equipment receptacle mated with the subsea control module.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates in general to hydraulically controlling valves and connectors of subsea equipment, such as a blowout preventer and lower marine riser package, and in particular to a control module containing electronics and hydraulic control valves.

2. Description of Related Art

Subsea Control Modules (SCMs) are commonly used to provide well control functions during the production phase of subsea oil and gas production. Typical well control functions and monitoring provided by the SCM are as follows: 1) Actuation of fail-safe return production tree actuators and downhole safety valves; 2) Actuation of flow control choke valves, shut-off valves, etc.; 3) Actuation of manifold diverter valves, shut-off valves, etc.; 4) Actuation of chemical injection valves; 5) Actuation and monitoring of Surface Controlled Reservoir Analysis and Monitoring Systems (SCRAMS) sliding sleeve, choke valves; 6) Monitoring of downhole pressure, temperature and flowrates; 7) Monitoring of sand probes, production tree and manifold pressures, temperatures, and choke positions.

The close proximity of the typical SCM to the subsea production tree, coupled with its electro-hydraulic design allows for quick response times of tree valve actuations. The typical SCM receives electrical power, communication signals and hydraulic power supplies from surface control equipment. The subsea control module and production tree are generally located in a remote location relative to the surface control equipment. Redundant supplies of communication signals, electrical, and hydraulic power are transmitted through umbilical hoses and cables of any length, linking surface equipment to subsea equipment. Electronics equipment located inside the SCM conditions electrical power, processes communications signals, transmits status, and distributes power to devices such as, solenoid piloting valves, pressure transducers, and temperature transducers.

Low flowrate solenoid piloting valves are typically used to pilot high flowrate control valves. These control valves transmit hydraulic power to end devices such as subsea production tree valve actuators, choke valves and downhole safety valves. Pressure transducers located on the output circuit of the control valves read the status condition of control valves and their end devices. Auxiliary equipment inside the typical SCM consist of hydraulic accumulators for hydraulic power storage, hydraulic filters for the reduction of fluid particulates, electronics vessels, and a pressure/temperature compensation system.

An SCM is typically provided with a latching mechanism that extends through the body of the SCM and that has retractable and extendable dogs or cams thereon to engage a mating receptacle in a base plate.

Many previous devices have used an oil-filled chamber to compensate for hydrostatic pressure increase outside of the device during use to keep seawater away from electronics and cable assemblies. More progressive SCMs, such as, for example, those described in U.S. Pat. No. 6,161,618, by Parks et al. incorporated by reference in its entirety, provides a serially modular design which includes a dry electronics chamber located under a pressure dome.

Recognized by the inventors, however, is that further modularization can reduce cost of individual SCMs, especially where a customer only requires a partial package, can allow for additional redundancy, can enhance functionality and the number of functions a module is capable of performing, can enhance survivability during deployment, operation, and retrieval, and can reduce maintenance repair time and costs, along with many other benefits.

SUMMARY OF THE INVENTION

In view of the foregoing, embodiments of the present invention advantageously provide a base subsea control module applicable for use in both the drilling and production phase, or in other applications, including application as a front end of a blow-out preventer (BOP) control system. Embodiments of the present invention provide a subsea control module which is modularized beyond that of other prior devices to facilitate tailoring the device to meet specific customer needs, to provide for additional redundancy, to enhance functionality and the number of functions a module is capable of performing, to enhance survivability during deployment, operation, and retrieval, and to reduce maintenance repair time and costs, along with many other benefits. The design can allow for replacement and retrieval of a faulty subsea control module with a single remotely operated vehicle (“ROV”) deployment from a vessel.

More particularly, an embodiment of the present invention advantageously provides a subsea control module including a module body having an axial bore extending therethrough, a proximal or upper body end portion, a distal or lower body end portion, and a medial body portion extending therebetween. The medial body portion of the module body includes an elongate annular recess extending radially into the medial body portion to define a valve module receptacle. A plurality of, e.g., trapezoidal shaped valve modules are each replaceably positioned radially along an inner surface of the valve module receptacle, approximately flush with the proximal and the distal body end portions, and are adapted to communicate hydraulic fluid with a separate one of a plurality of spaced apart apertures in the medial body portion of the module body. Each valve module can include a valve module housing containing at least one, but typically a pair of directional control valves, oriented axially within the respective valve module housing along a same longitudinal axis to thereby reduce a lateral physical signature of the respective valve housing. The subsea control module can also include a plurality of containers positioned to contain distributed electrical component defining a plurality of pilot valve modules. Each pilot valve module can include a pilot valve housing containing a plurality of pilot valves, a plurality of pressure transducers, and a plurality of solenoids.

The subsea control module can also include a central core positioned within the axial bore of the module body and can include a proximal end portion, a distal end portion, and a medial portion having an external surface spaced radially inward from the axial bore of the module body to form an annular cavity therebetween, to contain electronic circuitry. Further, the proximal end and the distal end portions of the central core can each have diameters greater than that of the medial portion of the central core. Additionally, the central core can include a cylindrical cover extending around the medial body portion of the central core, around at least a portion of an exterior surface of the proximal end portion of the central core, and around at least a portion of an exterior surface of the distal end portion of the central core. The cylindrical cover can be positioned within the axial bore of the module body and can have an inner surface spaced radially apart from the exterior surface of the medial portion of the central core. As such, the cylindrical cover can seal the annular cavity to form a housing to contain the electronic circuitry, which can include an electronic control module positioned to communicate with each of the plurality of pilot valve modules, and electrical circuitry in a subsea equipment receptacle, which, in turn, can provide a communication link with a surface computer.

According to a preferred configuration, the annular cavity is characterized by being a dry, air-tight cavity formed between the module body and the central core, is purged of air and containing nitrogen at a pressure of at or near approximately atmospheric pressure, and each pilot valve housing can contain a dry, air-tight cavity, purged of air and containing nitrogen at a pressure of at or near approximately atmospheric pressure. This advantageously enhances maintainability of the components inside each cavity.

The proximal body end portion of the module body can include a plurality of passageways formed in the proximal body end portion, which are collectively positioned to communicate hydraulic fluid between the plurality of pilot valve modules and the plurality of valve modules to define a plurality of mating passageways. Similarly, the proximal end portion of the central core can include a plurality of passageways formed in the proximal end portion, which contain or house an electrical penetrator sealingly positioned to communicate control signals between the electronic control module and a separate one of the plurality of pilot valve modules. The subsea control module can further include a seal plate positioned between each of the plurality of pilot valve modules and the plurality of mating passageways of the module body and the plurality of passageways of the central core to seal an interface between the plurality of pilot valve modules and the respective passageways.

The subsea control module can further include a plurality of hydraulic couplings extending distally from the distal body end portion of the module body and a plurality of electrical couplings similarly extending distally from the distal end portion of the central core. A cylindrical outer protective cover extending around an exterior of the medial body portion of the module body and around an exterior of the distal end portion of the module body, also extends axially beyond a distal end surface of the distal body end portion of the module body, to provide damage protection to the plurality of couplings when coupling the subsea control module to a subsea equipment receptacle.

Various other features according to embodiment of the present invention are also provided to enhance functionality and the number of functions a module is capable of performing, to enhance survivability during deployment, operation, and retrieval, and to reduce maintenance repair time and costs, along with many other benefits.

DETAILED DESCRIPTION

FIGS. 1-5illustrate a subsea control module11that is modularized beyond that of other prior devices to facilitate tailoring the device to meet specific customer needs, to provide for additional redundancy, to enhance functionality and the number of functions a module is capable of performing, to enhance survivability during deployment, operation, and retrieval, and to reduce maintenance repair time and costs, along with many other benefits including allowing for replacement and retrieval of a faulty subsea control module with a single remotely operated vehicle (“ROV”) deployment from a vessel (not shown).

Referring toFIGS. 1,2and3, a subsea control module11, according to a preferred configuration, is employed to connect into subsea equipment, such as a subsea production tree, blowout preventer, lower marine riser package, or other subsea remotely operated equipment (not shown), through use of a subsea equipment receptacle12. Module11has a tubular body13with an axial bore15. An annular recess17extends around the exterior of body13, giving body13a spool-shaped configuration. At least one, but up to 16 directional control valve modules18each including, for example, a pair of directional control valves19are mounted in recess17. A cylindrical cover or sleeve20extends around body13, closing the outer side of cavity17.

A central core21is mounted inside body13. Core21has a cylindrical cover27spaced radially inward from bore15of body13, creating an annular cavity23. Electronic circuitry25is located within annular cavity23. In one embodiment, annular cavity23is purged of air, filled with nitrogen, and remains at or near atmospheric pressure while subsea. With this embodiment, there is no need to equalize the pressure of the atmosphere in the electronics cavity23with that of the sea. Alternately, annular cavity23could be filled with a dielectric fluid and pressure compensated.

A connecting rod29extends through a central passage in core21for connecting subsea control module11to a receptacle12mounted on a piece of subsea equipment. Rod29has a drive head31on its upper end for access by a tool of a ROV (not shown), and a latch mechanism30adapted to engage a mandrel (not shown) in the subsea electrical equipment receptacle12.FIG. 2illustrates the latching mechanism in the form of a collet30threadingly interfaced with the connecting rod29. When rod29rotates, the collet30clamps around a mandrel in the receptacle12. Continued rotation will draw the module11into the receptacle12. Reverse action will disengage the module11from the receptacle12.FIG. 3illustrates the latching mechanism30in the form of a set of dogs, which engage a female latching component in the receptacle12. Regardless of the configuration of the subsea control module latching mechanism, engagement and disengagement procedures are substantially the same.

Referring again toFIGS. 1,2and3, an ROV interface39mounts to central core21by a plurality of fasteners41. The illustrated ROV interface39is a cup shaped member to which an ROV secures to while rotating drive head31. Other interfaces are, of course, within the scope of the present invention.

As perhaps best shown inFIG. 4, in this illustrated configuration, a plurality of pilot valve modules43are mounted on the upper (proximal) end of body13. Each pilot valve module43is a pie-or wedge-shaped segment having a sealed chamber44. Other shapes are, of course, within the scope of the present invention. There are, however, benefits to the wedge-shape, as it has been found easier to maximize the number of pilot valve modules43capable of being positioned atop the proximal end of body13. One or more pilot valves45, one or more pressure transducers46, and associated electronic circuitry48(shown diagrammatically inFIG. 1) are mounted within chamber44of each pilot valve module43. Each pilot valve45includes a solenoid that when receiving an electrical signal, will open or close a supply of hydraulic fluid pressure to another element, such as one of the directional control valves19or another valve of the subsea equipment. Each pilot valve module43has a cap47that is secured by fasteners to the upper end. Chamber44within each pilot valve module43is sealed by cap47and isolated from chambers of adjacent pilot valve housings43. Chamber44remains at or near atmospheric pressure while subsea, e.g., purged of air and filled with nitrogen, or alternately, it could be filled with a dielectric fluid and pressure compensated.

At electrical penetrator49extends sealingly into each pilot valve module43. The lower end of each penetrator49is in communication with annular electronics cavity23(FIG. 1) for receiving electrical connections leading to electronic circuitry48, pilot valves45and transducers46. Also, each pilot valve module43has a plurality of hydraulic fluid ports/passageways51(only one shown), each extending from a pilot valve45, a pressure transducer46or other hydraulic porting to mating ports/passageways53(only one shown) within module body13. The pressure transducers46measure pressures in the hydraulic porting. One or more of the ports/passageways53serves as an output port/passageway and may lead to one of the directional control valves19or to a hydraulic coupling55on the lower (distal) end of body13of module11. Another of the ports/passageways53supplies hydraulic fluid pressure from one of the hydraulic couplings55to one or more of the pilot valves45. A plurality of at least partially annular recesses extending radially into the proximal body end portion and/or distal end portion of the body13to define a plurality of ring headers61distribute to or collect hydraulic fluid from at least one of the plurality of ports/passageways53, sealed with an at least partial outer ring62. A seal plate or other sealing mechanism52seals the interface between the various ports51and53.

The electronic circuitry48within each chamber44of each separate pilot valve module43monitors and controls pilot valves45and pressure transducers46of the respective pilot valve module43. Electronics circuitry48receives power from and communicates with electronics circuitry25in cavity23.

Referring again toFIG. 1, hydraulic couplings55protrude from the lower end of module body13. Sleeve20preferably extends downward past body13and encircles the assembly of couplings55to provide protection of the couplings55during at least initial engagement of the subsea control module11with the subsea equipment receptacle12. Further, at least one alignment key56interfaces with a corresponding guide (not shown) within the subsea equipment receptacle12to further aid in alignment of the couplings55with couplings of the subsea equipment receptacle12.

The hydraulic couplings55register with hydraulic ports/passageways53(see, e.g.FIG. 1) leading to or from directional control valves19, or register with ports/passageways53(see, e.g.FIG. 5) leading to and from pilot valve module43. Hydraulic couplings55will stab into mating engagement with couplings in the receptacle12for receiving hydraulic fluid pressure from a source and for transmitting hydraulic fluid pressure to the valves, connectors, actuators or other elements of the subsea equipment.

A plurality of electrical couplings57are similarly mounted to, and protrude, from the lower (distal) end of central core21of subsea control module11. Each electrical coupling57is connected to one or more wires leading to the electronic circuitry25for supplying power and communication. Fiber optic couplings may also be employed. Additional electrical couplings are available for powering and communicating with externally mounted instruments or devices.

The electronic circuitry contained in the electronic control module25shown schematically inFIGS. 1-3, which, as known and understood by those skilled in the art, can include a controller, memory coupled to the controller, and program code adapted to communicate with a surface computer positioned on a surface platform, through an umbilical cord connected to a subsea production tree, a lower marine riser package, or other subsea equipment (not shown).

Subsea control module11is small and lightweight enough to be installed subsea by the use of a remotely operated vehicle (“ROV”). The ROV stabs it into mating receptacle12, then rotates rod31. When fully connected, hydraulic fluid pressure is supplied to various hydraulic couplings55and electrical power and communication signals are supplied to electronic circuitry25and48, through electrical couplings57.

To perform a particular function, an electrical or fiber optic signal will be sent from a remote location, such as a vessel at the surface, for example, via the umbilical cord associated with the subsea equipment (not shown). This signal causes electronic circuitry25to provide power to one of the pilot actuated valves45, which in turn supplies hydraulic pressure to a hydraulic actuated device of the subsea equipment. In some instances, the pilot valves45will supply hydraulic pressure to one of the directional control valves19, which in turn supplies a larger volume of hydraulic pressure for causing larger users of hydraulic fluid pressure, such as annular preventers, and large valve actuators. Optionally, some of the pilot valves45may supply hydraulic pressure directly to a hydraulic device rather than via one of the directional control valves19.

Various embodiments of the present invention have several advantages. For example, embodiments of the present invention provide a modular design which concentrates actuatable hydraulic components in the removable subsea control module11, in contrast to having actuatable components in a mating subsea equipment receptacle12to thereby allow efficient maintenance—i.e., maintenance can be accomplished in a single ROV deployment by replacing the subsea control module having a malfunctioning component. That is, a single ROV deployment can provide removal of a faulty subsea control module11, replacement of a new subsea control module11, and can include ancillary maintenance operations.

Embodiments of the present invention optimize maintainability of individual subsea control modules11by distributing electrical and electrically actuated components most likely to fail, e.g., pilot valves45, solenoids, and pressure sensors46, across multiple miniature, e.g., one-atmosphere pilot valves modules43, which allows easy line replacement. Such modules43, according to an embodiment of the present invention, can be oriented in a wedge shaped design and can readily contain up to eight solenoids, eight correlated pilot valves, and up to ten pressure transducers. Advantageously, such configuration can allow for up to four functions per module43, and can allow for closed-circuit (return-to-surface) hydraulic function, in addition to open circuit (vent-to-sea) hydraulic function.

Embodiments of the present invention also optimize maintainability of the individual subsea control modules11by distributing hydraulic directional control valves19also across multiple miniature, e.g., directional control valves modules18, which allow for easy “off-line” replacement. Further, advantageously, by orienting the directional control valves19longitudinally within each module18, embodiments of the present invention have increased the number of directional control valves19to thirty-two, having, e.g., two per module18, and preferable with sixteen modules18oriented radially around an outer portion of a module body13to allow for the easy removal/repair/replacement.

Embodiments of the present invention include a module body13that contains no hydraulic tubings or fittings, but rather, provides a manifold design that reduces likelihood of leakage. The hydraulic passageways53can communicate with one or more ring headers61embedded along outer surfaces of the module body13. The ring headers61can advantageously function to distribute and/or collect hydraulic fluid.

According to embodiments of the present invention, advantageously, the module body13can include a relatively large central bore15, which accommodates central core21, with sealed cover27to provide an, e.g., one atmosphere, annular chamber or cavity23containing a central electronic control module25, which can electrically communicate with each pilot valves module43and with electronics or other communication media of the mating subsea equipment receptacle12. By providing such modular design with central control, problems with the subsea control module11can be easily identified, allowing less time spent on maintenance, and allowing for additional monitoring and emergency control.

Embodiments of the present invention also advantageously provide an extended protective cover or sleeve20, which can advantageously extend beyond the module body13to protect individual hydraulic couplings55and electrical couplings57which couple or mate with compatible couplings located in the subsea equipment receptacle12. The extension portion of the protective cover or sleeve20prevents damage during initial alignment during engagement of the subsea control module11with the subsea equipment receptacle12. Further, one or more alignment keys56can advantageously enhance initial alignment with the subsea equipment receptacle12, preventing risk of damage during mating of the subsea control module11with the subsea equipment receptacle12.

Various other functions according to one or more embodiments of the present invention, provide a completely ROV retrievable subsea control module11, which can provide up to thirty-two or more solenoids for drilling operations, up to sixty-four or more solenoids for production operations, up to ninety pressure transducers, up to thirty-two directional control valves, pilot filters, multiple supply manifolds, multiple hydraulic and/or electrical couplings, and electronics modules, up to eight electrical wet-mate connectors, a central collett latch, humidity detection in electrical chambers, and redundant power, communications, and controller; which does not require or include hydraulic tubing or fittings; and which allows for all repairs to be completed “off-line.”

This patent application is related to U.S. Patent Application No. 60/954,919, by Parks et al, titled “Control Module for Subsea Equipment,” filed on Aug. 9, 2007, U.S. patent application Ser. No.——————, by Parks et al, titled “Control System for Blowout Preventer Stack,” filed on Aug. 11, 2008, and U.S. Patent Application No. 60/955,085, by Parks et al, titled “Control System for Blowout Preventer Stack,” filed on Aug. 10, 2007, each incorporated by reference herein in its entirety.