Alternative energy battery charging systems for well construction

A drilling rig includes a rig component, an actuator coupled to the rig component, an electric power storage device coupled to the actuator and configured to cause the actuator to actuate. The actuator, by actuating, may perform a safety function in the rig component. The rig also includes a renewable power generator coupled to the electric power storage device and configured to supply at least some of the electric current to the electric power storage device that is supplied to the actuator.

BACKGROUND

Drilling rigs are used to bore into the earth to create a well and then to complete and extract hydrocarbons from the well. Drilling rigs include various mechanical devices to accomplish these functions, such as drawworks, top drives, pumps, etc., which may be powered electrically. The drilling rigs also include electrical components such as control panels, sensors, processors, etc., also powered by electricity. Where available, such electrical power is provided by connection to a power grid. However, land rigs may be positioned in remote locations, where grid access may be unavailable or for other reasons difficult to obtain. Providing power lines running to offshore rigs may likewise not be an option. Accordingly, diesel generators are used in such situations to power the rig.

Safety equipment is also provided on the drilling rigs. Generally, this safety equipment is configured to operate even in the absence of an active source of electrical power, e.g., the connection to the grid is interrupted, the generators go offline, etc. Moreover, the safety equipment may call for power at a greater rate than is practical for the electrical power source to provide on demand. Accordingly, the safety equipment may be powered using stored hydraulic energy. For example, hydraulic accumulators may be provided, and hydraulic fluid may be pumped into the accumulators at high pressure when power is available. In an emergency event, the energy stored in the accumulators may be delivered rapidly to the safety equipment, even if electrical power has been lost.

A blowout preventer (BOP) provides an example of such safety equipment. A BOP may be positioned at the wellhead may have one or more rams that are configured to shear a tubular extending therethrough, thereby preventing fluid from escaping from the well into the ambient environment in an emergency situation. In the event of a power loss, valves are operated to direct stored hydraulic fluid from the accumulators to the shear rams, which in turn actuate and seal the BOP.

However, as wells become more complex and BOP stacks become larger, the size of the accumulators called for to deliver the large amounts of energy used to actuate the shear rams can present a challenge. In offshore contexts, rig space is at a high premium, and thus it may be desirable to avoid devoting large portions of the rig to emergency accumulators. In land-based drilling, such large accumulators can present a transportation and space issue as well.

SUMMARY

Embodiments of the disclosure include a drilling rig that includes a rig component, an actuator coupled to the rig component, an electric power storage device coupled to the actuator and configured to cause the actuator to actuate. The actuator, by actuating, may perform a safety function in the rig component. The rig also includes a renewable power generator coupled to the electric power storage device and configured to supply at least some of the electric current to the electric power storage device that is supplied to the actuator.

Embodiments of the disclosure further include a method for powering a rig component. The method includes generating electric current using a renewable power generator of a drilling rig, storing the electric current in an electric power storage device, and actuating an actuator coupled to the rig component by supplying the electric current that was stored from the electric power storage device to the actuator or to an electric-to-hydraulic conversion device that supplies hydraulic power to the actuator.

Embodiments of the disclosure also include a drilling rig including a rig component including a blowout preventer having a ram, an actuator configured to actuate the ram, an electric power storage device coupled to the actuator and configured to supply electric current to the actuator, and a renewable power generator coupled to the electric power storage device and configured to supply at least some of the electric current to the electric power storage device that is supplied to the actuator, the renewable power generator including at least one selected from the group consisting of a solar panel, a wind turbine, a hydroelectric power generator, a geothermal power generator, and a regenerative power generator. The electric power storage device is coupled to a primary power source that provides a first current to the electric power storage device, and the renewable power generator is configured to provide a second current to the electric power storage device, the first current being greater than the second current. The renewable power generator is configured to provide a trickle charge to the electric power storage device, the electric power storage device is configured to discharge over time without actuating the actuator, and the trickle charge is configured to maintain the electric power storage device in a fully charged state.

DETAILED DESCRIPTION

In general, embodiments of the present disclosure may avoid or reduce the dependency on hydraulic accumulators in drilling rigs. The present disclosure may provide a rig that includes an electric power storage device, such as battery and/or capacitor arrays. The electric power storage device may be configured to provide near instantaneous power to various rig components that are often provided with power on a similar basis using an accumulator, e.g., in emergency situations or other relatively infrequent occasions. Additionally, the present disclosure may permit harvesting of alternative or “renewable” sources of energy to provide at least a part of this power. Such alternative sources of energy may be insufficient to provide on-demand power at the level used in emergency situations, such as to actuate a ram in a BOP; however, such power may be called for relatively infrequently, while such renewable energy sources may be available almost continuously. Accordingly, the renewable energy sources may be harnessed over time, using the electric power storage device. The stored power may then be released, e.g., rapidly, in order to actuate a rig component, and/or to power various other components of the rig, during a loss of primary power. Various other aspects of the present disclosure will be apparent from the following description of one or more illustrative embodiments, and the foregoing introduction should not be considered exhaustive.

FIG.1illustrates a schematic view of a drilling rig100, according to an embodiment. The drilling rig100may be an offshore, surface, or land rig. The drilling rig100may include the components and machinery that handle and advance tubulars into a well, withdraw the tubulars from the well, and circulate fluid (e.g., drilling mud) in the well. The drilling rig100may also include the rig floor, substructure, and mast, associated structures, seafloor components, and various downhole components, depending on the context in which the drilling rig100is employed.

As shown, the drilling rig100may generally include a rig component102. The rig component102may be any type of powered component for a drilling rig100, e.g., drawworks, various motors/drivers to manipulate the position of tubular handling components, rotating components (e.g., top drive), health and safety mechanism, sensors, etc. In a specific embodiment, the rig component102may be or include a blowout preventer (BOP). For example, the BOP102may include one or more shear rams that may be capable of shearing an oilfield tubular so as to seal the well.

The drilling rig100may also include an actuator104that is coupled to the rig component102. The actuator104may be mechanically and/or hydraulically coupled to the rig component102, so as to transmit energy via hydraulic fluid and/or movement of mechanical elements (e.g., shafts, gears, etc.) thereto. For example, the actuator104may be an electric motor, a pump, or the like. Continuing with the example of a blowout preventer, the actuator104may include a device that causes the shear ram of the BOP102to actuate, e.g., a pump or an electric motor. Accordingly, by actuating, the actuator104may perform a safety function, e.g., causing the shear ram to seal the BOP.

The drilling rig100may include an electric power storage device106coupled to the actuator104and configured to supply energy (e.g., electric current) to the actuator104. The electric power storage device106may include one or more batteries, one or more capacitors, other electrical devices, or a combination thereof. In some embodiments, the electric power storage device106may discharge slowly, over time, even if not used to actuate the actuator104, as described below.

In some embodiments, the electric power storage device106may be or include an uninterruptable power source (UPS), e.g., for the actuator104. Accordingly, in the event of a loss of rig power (e.g., generator failure, blackout in a power grid, etc.), the electric power storage device106may continue to supply power to the actuator104, at least temporarily. The electric power storage device106may thus serve a dual purpose. First, the electric power storage device106may accumulate power that is not otherwise being used, so that it is available on an emergency (or other infrequent) basis in a quantity and rate that is greater than what may be generated. Second, the electric power storage device106may be capable of maintaining the availability of the safety functionality in the rig component102despite the loss of power, e.g., by powering the actuator104. The electric power storage device106may also power other components of the drilling rig100, either continuously or on an emergency basis, as will be described in greater detail below.

The drilling rig100may further include a renewable power generator108and a primary power source109, both of which may be coupled to the electric power storage device106. The primary power source109may be or include a diesel generator, a public power grid, or any other suitable source of electrical power that may be used to power normal rig operations. The primary power source109may be capable of supplying sufficient energy to the drilling rig100so that its various components are operable continuously. Further, the primary power source109may be used to provide at least a partial, initial charge for the electric power storage device106.

The renewable power generator108may also be configured to supply the electric current to the electric power storage device106. The renewable power generator108may provide a “trickle” charge, e.g., a relatively low current (in comparison to that potentially provided by the primary power source109), to the electric power storage device106. The electric power storage device106may employ this trickle charge to remain full, thereby counteracting natural discharges thereof that occur over time in the power storage components (e.g., battery or capacitors discharging slowly), as mentioned above. In some embodiments, the renewable power generator108may be a wind turbine, solar panel, geothermal generator, hydroelectric (e.g., wave or tidal) generator, or a combination of one or more thereof. In another example, the renewable power generator108may be configured to harness regenerative energy and store it in the electric power storage device106. Lowering a mass from the top of a mast toward the rig floor may be an example of such regenerative energy, which may be employed to drive the renewable power generator108.

The drilling rig100may also include a control panel110. The control panel110may be in communication with and configured to control the rig component102and/or the actuator104. The control panel110may generally be or include a processor, and thus may be a powered device. The control panel110may send signals to the rig component102and/or the actuator104, so as to implement functions, receive sensor readings, and provide information to a user, e.g., via a human-machine interface (e.g., a touch screen). In an embodiment, the electric power storage device106may supply power to the control panel110, such that the control panel110may be operable during times when rig power (e.g., from the primary power source109) is otherwise lost. Further, the control panel110may be configured to control the power supplied from the electric power storage device106to the actuator104, so as to control the functioning of the actuator104.

In at least some embodiments, the actuator104or the rig component102may be hydraulically operated. Since the electric power storage device106stores electric power, and generally not hydraulic power, the rig100may include an electric-to-hydraulic conversion device120. In some embodiments, the actuator104may integrate such conversion capabilities, or may be run on electricity, and thus the electric-to-hydraulic conversion device120may be omitted. However, in the illustrated embodiment, it is included and serves to convert the electric power provided, e.g., on demand in response to commands from the control panel110, from the electric power storage device106into hydraulic power that drives the actuator104.

FIG.2illustrates a schematic view of a drilling rig200, according to an embodiment. The drilling rig200may be similar to the drilling rig100, but may, for example, illustrate various aspects in greater detail. The drilling rig200may thus include the rig component102, which may be, as shown, a BOP. The BOP102may include various valves, rams, seals, and/or other components that may be actuated via one or more (e.g., hydraulic) actuators. The drilling rig200may also include the primary power source109(e.g., a diesel generator) and the renewable power generator108, which may be coupled to the electric power storage device106. As shown, the primary power source109and the renewable power generator108may be electrically tied together and operate, in at least some situations, redundantly. Further, at least some of the power may be stored in the electric power storage device106, while other portions may be used on-demand, e.g., for rig operations.

In other embodiments, power may be employed both on-demand via the electric power storage device106. For example, the electric power storage device106may include a first UPS201and a second UPS202. The first UPS201may be coupled directly to the primary power source109, and the second UPS202may be coupled directly to the renewable power generator108. A cross-over link may be provided, however, which may permit one of the renewable power generator108or primary power source109to power either/both of the UPSs201,202, e.g., when the other of the renewable power generator108and the primary power source109is offline or otherwise not providing electricity to the rig200.

The actuator104may likewise include two electric actuators210,212, one connected directly to each of the UPSs201,202, respectively. Further, a cross-over may be provided such that either UPS201,202is capable of providing power to either or both of the electric actuators210,212. The electric actuators210,212may each include an electric pump motor assembly, an electric accumulator, or both. The fluid may be pressurized and provided to the rig component102, e.g., by control from the control panel110.

The control panel110may be coupled to the electric power storage device106, e.g., to either or both of the UPSs201,202. For example, the UPS201may be configured to power the panel110during normal operation, while the UPS202may be configured to power the panel110during a rig power loss, e.g., when the primary power source109is offline. In another embodiment, the UPS202may be configured to power the panel110during normal operations, and the UPS201may be configured to power the panel110during rig power loss (e.g., using power stored on-board). Either or both UPSs201,202may be configured to provide power to the electric actuators210,212so as to power the functionality thereof.

The panel110may further include a human-machine interface (HMI)214. In an embodiment, the HMI214may include a touch screen or any other display providing a graphical user interface or another interface for interaction with a human controller, whether at the drilling rig200or remotely therefrom.

In some embodiments, the drilling rig200may include one or more hydraulic accumulators. The hydraulic accumulators may be coupled to hydraulic pumping units, which may be controlled via the control panel110. Thus, the hydraulic accumulators may be maintained in a charged state and may be released on demand, e.g., to provide power in addition to the UPSs201,202and the electric actuators210,212to the BOP102(e.g., a shear ram thereof).

FIG.3illustrates a schematic view of another drilling rig300, according to an embodiment. The drilling rig300may be a floating offshore rig. The surface components of the drilling rig300may thus be connected to the rig component102(e.g., BOP) via a riser302. An electrical (“MUX”) cable304may electrically connect together the surface components and the rig component102. The actuator104and the electric power storage device106(e.g., an electrical accumulator, a saltwater ion charged battery, etc.) may be located at the seafloor, as shown. Accordingly, function read back times (e.g., time between signaling an actuation to occur and receiving a signal representing that the actuation has occurred) may be reduced, since the hydraulic lines are relatively short, as between actuator104and the rig component102, while the electric cable304traverses the relatively long distance between the surface and the sea floor, providing near instantaneous power and/or signal transmission therethrough.

In an embodiment, the renewable power generator108may be positioned at the surface, as schematically depicted. As such, the renewable power generator108may be configured to harness wind, solar, or hydroelectric power. In other embodiments, components of the renewable power generator108may instead or additionally be positioned at the sea floor. For example, a turbine may be positioned at the sea floor and configured to harness subsurface water currents, or a geothermal generator may extend into the earth below the seabed. The primary power source109may likewise be positioned at the surface.

In the illustrated embodiment, the electric cable304brings power from the renewable power generator108and/or the primary power source109, which may be provided to the electric power storage device106via the rig component102. In other embodiments, the power could be supplied directly to the electric power storage device106, e.g., via a separate cable. In a hybrid electric-hydraulic embodiment, the electric power storage device106may supply electric current to an electric-to-hydraulic conversion devices (e.g., the hydraulic conversion device120ofFIG.1), which may then supply energy, e.g., mechanical or hydraulic, to the actuator104and/or the rig component102. In an electric actuation embodiment, the electric power storage device106may supply electric power directly to the actuator104.

FIG.4illustrates a side, schematic view of an electric-to-hydraulic conversion device400, according to an embodiment. The electric-to-hydraulic conversion device400may be an example of the hydraulic conversion device120ofFIG.1. As shown inFIG.4, the electric-to-hydraulic conversion device400may include a housing402, with a top cap403and a bottom cap404on either axial side thereof (e.g., in a cylindrical embodiment of the housing402).

A partition wall406may be positioned in the housing402, such that a balance chamber408and an actuator compartment410are defined within the housing402, on opposite sides of the partition wall406. An electric actuator412may be positioned within the actuator compartment410. The electric actuator412may be a motor, for example. In some embodiments, a battery may also be positioned in the actuator compartment410. In some embodiments, the battery may be part of the electric power storage device106(FIG.1).

A piston414may also be positioned in the housing402and may be connected to the electric actuator412via a piston rod416. The piston rod416may extend through the balance chamber408and through the partition wall406to the electric actuator412. The electric actuator412may thus be configured to move the piston414axially within the housing402via the piston rod416. Hydraulic fluid may be disposed within the balance chamber408between the piston414and the partition wall406.

The housing402may also define a function chamber420between the bottom cap204and the piston414. Hydraulic fluid may be contained within the function chamber420and may be expelled through a port422in the bottom cap404by movement of the piston414toward the bottom cap404. Thus, energizing the electric actuator412may drive the piston414, and thereby drive the hydraulic fluid from within the housing402to an external device (e.g., the actuator104and/or the rig component102), so as to convert electrical energy to potentially high-pressure hydraulic fluid.

FIG.5illustrates a flowchart of a method500for powering a rig component102, according to an embodiment. The method500may be executed, for example, by operation of one or more embodiments of the drilling rig100,200,300discussed above, or others.

The method500may include receiving electric current from a primary power source, as at501. As noted above, the primary power source may be a public power grid, a diesel generator, or any other power source that is configured to supply normal operating power to the rig. The method500may also include generating electric current from a renewable power source on a drilling rig, as at502. The electric current, both received at501and generated at502, may be stored in an electric power storage device on the drilling rig, as at504. For example, the electric current received at501may provide an initial charge of the electric power storage device106. An initial charge may be provided when the electric power storage device is drained, e.g., prior to a first actuation of an actuator104(e.g., at rig up or when the electric power storage device106is installed or otherwise initiated) or after a given actuation, to replace the power discharged to actuate the actuator104.

The electric current generated at502may be received on an on-going or intermittent basis as a “trickle” charge that continuously floats or “tops-off” the batteries, capacitors, etc., of the electric power storage device106. This may maintain the electric power storage device106in a fully-charged state (e.g., when a small amount of power discharges, the small amount is replenished via the trickle charge either intermittently or continuously). For example, primary power source109may be configured to provide a first amount of power, and the renewable power generator108may be configured to provide a second amount of power, which may be less than the first amount of power.

In some embodiments, the method500may include powering rig operations directly, using the primary power source109, and/or using power stored in the electric power storage device106(e.g., as a UPS), as at505.

The method500may further include actuating the actuator104coupled to the rig component102by supplying the electric current that was stored from the electric power storage device106to the actuator104(or to an electric-to-hydraulic conversion device120, which then supplies energy to the actuator104), as at506. In some embodiments, actuating the actuator104includes causing a shear ram (actuator104) to seal a BOP (rig component102). Further, the actuator104may call for more power to actuate over a short period of time than is available on a continuous basis from the primary power source109and/or the renewable power generator108. For example, a third level of power may be called for to actuator the actuator104, which may be greater than the first level of power and the second level of power, and, in some cases, may be greater than the sum of the first and second levels of power. Thus, the method500may leverage the stored power in the electric power storage device106, which may provide the third level of power that is sufficient to actuate the actuator104.

In an embodiment, at508, the method500may also include detecting a loss of power in the primary power source109, e.g., prior to actuating the actuator104at506. In response, the method500may include powering a control panel (and/or event logger, communications panel, etc.) that is connected to the actuator104using electric current from the renewable power generator108while the primary power source109(e.g., generator) is not operating, as at510. In some embodiments, the control panel110may be continuously powered by the electric power storage device106, e.g., even when the primary power source109is operating, and thus the electric power storage device106may operate as a UPS for the control panel110. This may preserve uninterrupted control capabilities via the control panel110even in the event of a loss of power in the primary power source109. Further, in some embodiments, actuating at506may include actuating the actuator104during the loss of power from the primary power source109.

In some embodiments, the drilling rig may be an offshore, e.g., floating rig. In such an embodiment, the electric power storage device106and the actuator104may be located at a seafloor. The renewable power generator108may be located at a surface of the ocean. Accordingly, storing the electric current at504may include transmitting electric current through an electric cable304extending from the surface to the seafloor to the electric power storage device106.

As used herein, the terms “inner” and “outer”; “up” and “down”; “upper” and “lower”; “upward” and “downward”; “upstream” and “downstream”; “above” and “below”; “inward” and “outward”; and other like terms as used herein refer to relative positions to one another and are not intended to denote a particular direction or spatial orientation. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members.”

The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. Moreover, the order in which the elements of the methods are illustrated and described may be re-arranged, and/or two or more elements may occur simultaneously. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.