Sub for a pipe assembly and system and method for use of same

A sub for a pipe assembly and system and method for use of the same are disclosed. In one embodiment, the sub includes a mandrel having a body section including an internal flow passage that extends generally axially through the mandrel from an upper connection end to a lower connection end. A battery charger is located within a recessed region within the mandrel. Capacitors include opposing spaced plates having contact segments thereon. An output power increasing, electrically resistive fluid is held within and partially fills an enclosed chamber. In response to movement of the sub, induced relative motion between the output power increasing, electrically resistive fluid and contact segments varies the fluid-contact segment contact within the enclosed chamber, thereby generating an electrical charge. An electronic circuit, which is coupled to the opposing spaced plates, is configured to transfer the electrical charge to a battery associated with the mandrel.

TECHNICAL FIELD OF THE INVENTION

This invention relates, in general, to pipe assemblies and, more particularly, to a sub for a pipe assembly and system and method for use of the same that provide battery capacity applicable to various oil field operations such as drill strings with downhole electronics.

BACKGROUND OF THE INVENTION

Electronics in oil field operations are often located in subs and the like and rely on a storage battery for operating power. Since the physical dimensions within a sub are limited, access to a sub is difficult, and conditions at the sub with respect to heat and pressure extreme, battery capacity is often strained. Accordingly, there is a need for enhanced systems and methods for providing improved battery capacity.

SUMMARY OF THE INVENTION

It would be advantageous to improve battery capacity in pipe assembly components, such as subs. It would also be desirable to enable a mechanical-to-electrical conversion solution that would convert motion to electrical energy, which would be thereafter be transferred to the battery in the sub, thereby enhancing battery capacity. To better address one or more of these concerns, a sub for a pipe assembly, such as a drill string, and system and method for use of the same are disclosed. In one embodiment of the sub, the sub includes a mandrel having a body section including an internal flow passage that extends generally axially through the mandrel from an upper connection end to a lower connection end. A battery charger is located within a recessed region within the mandrel.

Capacitors, which may be supercapacitors, are located within the battery charger and each of the pair of capacitors includes opposing spaced plates having contact segments thereon. An output power increasing, electrically resistive fluid is held within and partially fills an enclosed chamber that is boundaried by the contact segments. In response to movement of the sub, such as rotational, vibrational, or linear movement during a drilling operation, induced relative motion between the output power increasing, electrically resistive fluid and contact segments varies the fluid-contact segment contact within the enclosed chamber, thereby inversely alternating the capacitance between the pair of capacitors and triboelectrically generating an electrical charge. An electronic circuit coupled to the opposing spaced plates is configured to transfer the electrical charge to a battery associated with the mandrel. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially toFIG. 1, therein is depicted one embodiment of a system for utilizing a sub for a pipe assembly, which is schematically illustrated and designated10. The system10being employed within drilling operation12includes a drilling rig14located at a surface16of a well18. The drilling rig14provides support for a pipe assembly20depicted as a drill string22. As shown, the drill string22penetrates a rotary table24for drilling a borehole26through subsurface formations28. The drill string22includes a kelly30, a drill pipe32and a bottom hole assembly34. By way of example, the bottom hole assembly34may include a drill collar36, a downhole tool38, and a drill bit40. Additionally, the bottom hole assembly34may include one or more subs, such as sub50, which is located between pipe assemblies52,54.

During drilling operations, the drill string22may be rotated by the rotary table24. In some implementations, the bottom hole assembly34may also be rotated by a downhole motor. Also during drilling operations, a mud pump56may pump drilling fluid from a mud pit58through a hose60into the drill pipe32down to the drill bit40. The drilling fluid can flow out from the drill bit40and return to the surface16through an annular area62between the drill pipe22and the sides of the borehole26. The drilling fluid may then be returned to the mud pit58, where the drilling fluid is filtered. An instrument hub64is integrated into the drill string22and coupled to the kelly30. In some embodiments, the instrument hub64may include transceivers for communications with electronics, such as downhole instrumentation. The system10also includes a ground station66having an antenna68to provide wireless communications with the instrument hub64.

The drill string22, including the sub50, may include different electronics positioned therein which provide control or monitor different downhole parameters, such as downhole temperature, pressure, characteristics of the subsurface formations (e.g., resistivity, density, porosity), or characteristics of the borehole (e.g., size, shape), for example. The drill string22may also include a measurement-while-drilling (MWD) system or a logging-while-drilling (LWD) system. The drill string22may also include various forms of transmitters to convey data with the instrument hub64, for example. Such transmitters may be mud-pulse transmitters, wireless transmitters, wired-drill pipe transmitters, or acoustic transmitters, for example. Although a particular drill string is presented, it should be noted that additional and alternative components may be used in constructing the drill string22depending on the environment and operational parameters related to drilling the wellbore. By way of example, the drill string may support vertical drilling operations or directional drilling operations.

The sub50may be any of a number of different types of subs including any component of the pipe assembly including the drill string, such as a short drill collar or a thread crossover. The sub50and teachings presented herein may be part of a new sub or a retrofitted sub, for example. By way of further example, the sub50may be a saver sub, a repeater sub, an interface sub, a sensor sub, a ball valve sub, drilling performance sub (DPS), multiple propagation resistivity (MPR) sub, directional sensor sub (DSS), or hydraulic power control sub, for example. In one embodiment, the sub creates an electrical charge and stores the electrical charge in order to supply electricity to the electronics. As will be discussed hereinbelow, in response to movement of the sub50, such as rotational, vibrational, or linear movement, the sub50generates an electrical current.

Referring now toFIG. 2,FIG. 3, andFIG. 4, the sub50includes a body80having an upper end82and a lower end84. A mandrel86having a body section88includes an internal flow passage90that extends generally axially through the mandrel86from an upper connection end92at the upper end82to a lower connection end94at the lower end84. The internal flow passage90permits high pressure fluid flow therethrough. Each of the upper connection end92and the lower connection end94may be appropriately threaded for mating engagement within the pipe assembly and respectively with pipe assemblies52,54. Recessed regions96,98,100,102,104,106are located within the mandrel86.

With respect to the recessed region96, a battery charger110, a battery112, and electronics shown as sensor114are located therein. The battery charger110is coupled to the battery112, which in turn supplies power to the electronics. A passage116extends from the recessed region96and contains a communication wire118that may extend to another portion of the drill string22such as pipe assembly52via the appropriate coupling. With respect to the recessed region98, a battery charger120and a battery122are located therein and electrically coupled. Electronics circuitry124connects the battery122to sensors126, which are located within the recessed region100. With respect to recessed region102, a battery charger128, a battery130, and a sensor132are located. The battery charger128is coupled to the battery130, which supplies power to the sensor132. As shown, transceiver134extends from sensor132.

As further illustrated by the cross-sectional view ofFIG. 4, multiple recessed regions96,98,100,102,104,106may be formed in body section88at desired angular positions depending on the configuration and number of components required. Furthermore, in one embodiment, a removable cover136may be selectively moved into place over a recessed region, such as the recessed region96, to protect the components from damage. By way of example, the cover136may comprise a cylindrical sleeve with seals that slides into place over the recessed region96. It should be understood that in other embodiments, the cover utilized to protect the components with the recessed regions96,98,100,102,104,106is not removable. Further, it should be understood that the number and positions of the recessed regions will vary and variations are within the teachings presented herein. As will be discussed in further detail hereinbelow, rotational, vibrational, and linear motion, for example, of the drill string will create an electric charge in the battery charger which will be stored in the battery and, in turn, used to power the electronics. Moreover, the battery charger presented herein may work with any type of pipe assembly, not just the illustrated drill string.

Referring now toFIG. 5, one embodiment of the battery charger110is depicted. A battery charger housing150forms a portion of the sub50and a liquid triboelectrical generator152includes multiple electrostatic energy generators, for example, electrostatic energy generators154,156,158,160,162coupled to electrical circuitry (not shown) and separated by physical separators164,166,168,170. As will be discussed in further detail hereinbelow, the capacitors utilized in the electrostatic energy generators154,156,158,160,162may be supercapacitors or variable capacitors. The liquid triboelectrical generator152utilizes the triboelectric effect in generating an electric charge which may recharge the battery112, for example, associated with the sub50.

The triboelectric effect is known as a transfer of charge between two contacting materials, which become electrically charged in opposite signs. Though the triboelectric effect is known for many centuries, its fundamental mechanism is still under investigation. Only recently was it applied in energy harvesting for fabrication of triboelectric generators converting small-scale mechanical energy into electricity that paves the way for simple and low-cost green-energy technology. However, most of the proposed triboelectric generators are limited in efficiency by indispensable requirement for constant change of cavity volume and/or utilization of sliding surfaces. Also these work best only under dry conditions. However, triboelectricity is known to exist when liquids flow through insulators. For example, a voltage variation of 0.3 V was observed upon water flow through a one meter-long millimeter-diameter rubber pipe and surface charge density of over 5 μC/m2 was measured on each water droplet dispensed from a Teflon-coated pipette tip.

The present battery charger110may include a design of a liquid triboelectric generator comprising a liquid-filled capacitor or supercapacitor as the key element enabling the increase of the efficiency of generation of electricity. The proposed approach is based on the relation between the electrical charge Q and voltage V and capacitance C:
Q=CV[Equation (1)]

Therefore the generated electrical current I (which is the time derivative of the triboelectrical charge) appears to be proportional to the capacitance and its variation in time:

I=d⁢⁢Qd⁢⁢t=C⁢∂V∂t+V⁢∂C∂t[Equation⁢⁢(2)]
where d/dt and ∂/∂t represent total and partial derivative with time correspondingly.

With a supercapacitor which is not fully filled with liquid and separated into more than one individually contacted segments, flow of liquid inside the cavity or series of enclosed chambers causes generation of the triboelectric charge. Therefore the first term in Equation (2) is the variation of the potential across the opposite electrodes owing to the triboelectrically-generated charges, while the second term is the variation of the capacitance due to the local change of capacitance in the segments of the supercapacitor due to the flow of liquid. From Equation (2) one can see that utilization of such triboelectricity-enabled supercapacitor makes it possible to increase the efficiency of triboelectrical generation by a factor of the ratio of electrical capacitance C of the supercapacitor to that of the conventional triboelectrical generator, which can be many orders of magnitude. Supercapacitors are known to feature extremely high capacitance, up to a few kilofarads.

The triboelectricity-enabled, liquid-filled capacitor or supercapacitor may feature the internal volume (cavity) which is only partially filled with liquid, thus enabling for the movement of the liquid inside the cavity. The triboelectricity-enabled supercapacitor also features two or more individually contacted segments that enable the outflow of the electrical charge, which is triboelectrically-generated by the movement of the liquid inside the cavity.

Referring now toFIG. 6, one embodiment of the electrostatic energy generator154is depicted in further detail. As discussed, the battery charger housing150is located within the sub. The battery charger housing150includes an enclosed chamber180. A pair of variable capacitors182,184which may be supercapacitors or variable capacitors, are located within the battery charger housing150and each of the pair of capacitors182,184includes opposing spaced plates186,188,190,192which act as electrodes, having respective contact segments194,196,198,200thereon. As shown, in one embodiment, the contact segments194,196,198,200form at least a portion of the enclosed chamber180.

An output power increasing, electrically resistive fluid202is held within the enclosed chamber180and the output power increasing, electrically resistive fluid202partially fills the enclosed chamber180such that fluid motion varies the fluid-contact segment contact within the enclosed chamber180. As will be discussed in further detail hereinbelow, in response to movement of the sub50, induced relative motion between the output power increasing, electrically resistive fluid202and contact segments194,196,198,200varies the fluid-contact segment contact within the enclosed chamber180, thereby inversely alternating the capacitance between the pair of capacitors182,184and triboelectrically generating an electrical charge.

An electronic circuit204is coupled to the opposing spaced plates186,188,190,192of the pair of variable capacitors. In one embodiment, the electronic circuit204may include diode bridges206,208and an electrical accumulator210. The electronic circuit204may be configured to transfer the electrical charge to the battery112associated with the sub50. In one event, the electrical accumulator210may be at least partially integrated with the battery112.

Referring now toFIG. 7, another embodiment of the electrostatic energy generator154is depicted. In this embodiment, the plates186,188,190,192feature an electret material220. Electret is a dielectric with a quasi-permanent electric charge or dipole polarization and therefore generates internal and external electric fields. Therefore, utilization of the electret material facilitates generation of the electrical double-layers on the liquid-plate interface (which are crucial for high capacitance of the supercapacitors) without a voltage applied to the electrodes of the triboelectricity-enabled capacitor. Additionally, as shown, the enclosed chamber180may include a dielectric material222,224interposed within the contact segments194,196,198,200between the opposing spaced plates186,188,190,192.

Referring now toFIG. 8, a process state diagram depicting one embodiment of the electrical energy generation process is shown. In general, in a fluid inflow cycle, movement of the output power increasing, electrically resistive fluid202occurs proximate to the opposing spaced plates186,188such that the output power increasing, electrically resistive fluid202is physically occupying the enclosed chamber180. The output power increasing, electrically resistive fluid202inflow cycle causes electrostatic charges with opposite signs to be triboelectrically generated and distributed proximate the opposing spaced plates186,188. A temporary electrical circuit is created across the opposing spaced plates186,188thereby generating a voltage/current peak. Thereafter, in a fluid outflow cycle, wherein movement of the output power increasing, electrically resistive fluid202moves away from the opposing spaced plates186,188and physically evacuating that portion of the enclosed chamber180, neutralization of the electrostatic charges occurs. Electrons flow to the electronic circuit204until equilibrium is reached between the opposing spaced plates186,188.

More specifically, at State (a), which may be the initial state of the triboelectricity-enabled liquid-filled capacitor or supercapacitor, the enclosed chamber180, which is not fully filled with the output power increasing, electrically resistive fluid202, includes a pair of capacitors182,184each including the opposing spaced plates186,188,190,192having the contact segments194,196,198,200thereon. For purposes of illustration, it should be appreciated that with respect toFIG. 8, the process of the triboelectrical generation is described for the contact segments194,196proximate the spaced plates186,188. It should be further appreciated that a similar description and process applies to the contact segments198,200proximate the spaced plates190,192as well.

At State (b), with respect to the fluid inflow cycle, with the movement of the output power increasing, electrically resistive fluid202inside the enclosed chamber180, electrostatic charges with opposite signs are triboelectrically generated and distributed on the two internal surfaces of the opposing spaced plates186,188of the supercapacitor segment represented by the opposing spaced plates186,188. At State (c), the neutral metal electrodes associated with the opposing spaced plates186,188are charged via the triboelectric effect. At State (d), continuing the fluid inflow cycle, electrons flow across the electrical circuit204generating a voltage/current peak. At State (e), a temporary potential equilibrium forms in the supercapacitor segment. Beginning the fluid outflow cycle, at State (f), most of the electrostatic charges on the internal surfaces are neutralized during the fluid outflow process prior to, at State (g), electrons flow back via the electrical circuit204until the potential equilibrium forms between the two metal electrodes associated with the opposing spaced plates186,188. This enables unidirectional flow of the electrical current out of the triboelectrical generator to the electrical circuit204, including the electrical accumulator210and/or battery112to be charged.

In another embodiment, depicted inFIG. 9, the battery charger110may be a motion-activated charger230for the sub50that includes the battery charger housing150having contact members232,234defining an inner chamber236. A moveable element238within the battery charger housing co-acts with the contact members232,234of the battery charger housing150to generate an electrical charge. This embodiment of the battery charger110includes electrical circuitry that is configured to transfer the electrical charge generated to a storage battery. More particularly, in one embodiment, the moveable element238may be an output power increasing, electrically resistive object partially filling the enclosed inner chamber236such that motion of the moveable element238varies the moveable element-contact segment contact within the enclosed inner chamber236. In response to movement of the sub50, induced relative motion between the output power increasing, electrically resistive moveable element238and contact members232,234varies the moveable element-contact segment contact within the enclosed inner chamber236, thereby inversely alternating the capacitance between the pair of supercapacitors and triboelectrically generating an electrical charge.

By way of example and not by way of limitation, in the embodiment, the battery charger housing may have dimensions of 82 mm by 110 mm with a 2.20 mm thickness and the inner chamber116may have dimensions of 78 mm by 100 mm with a 1.00 mm thickness. It should be appreciated that the shape of the moveable element238may vary and, by way of example and not by way of limitation, may include general horizontal shapes or vertical shapes or even irregular shapes. Further, the moveable element238may include one or more individual pieces. Therefore, in use, the constant movement of the battery charger housing150will create a constant movement of the moveable element238that causes friction between the battery charger housing150and the moveable element238to create the most static electricity possible. It should be further understood that fluid240within the enclosed inner chamber236about the moveable element238may include an electrically resistive fluid, such as output power increasing, electrically resistive fluid202.

In one implementation, the moveable element238is disposed within the enclosed inner chamber236, which may be the enclosed chamber180, is an output power increasing, electrically resistive object partially filling the enclosed inner chamber236such that motion of the moveable element238varies a moveable element-contact segment contact within the enclosed inner chamber236, thereby inversely alternating the capacitance between the pair of supercapacitors and triboelectrically generating an electrical charge. In an instance of this embodiment, each pair of variable capacitors, which may be represented by contact members232,234, are configured for an intake cycle wherein movement of the output power increasing, electrically resistive moveable element238proximate to the opposing spaced plates186,188,190,192and physically occupying enclosed chamber thereto. The intake cycle causes electrostatic charges with opposite signs to be triboelectrically generated and distributed proximate the opposing spaced plates186,188,190,192. A temporary electrical circuit created across the opposing spaced plates186,188,190,192and generating a voltage/current peak.

Following the output cycle, in an output cycle, movement of the output power increasing, electrically resistive moveable element238occurs away from the opposing spaced plates186,188,190,192and physically evacuating the enclosed chamber180. The fluid outflow cycle causes the neutralization of the electrostatic charges and electrons flow via the electrical circuit to the electronic circuit until equilibrium is reached between the opposing spaced plates.

In a further embodiment, a charging system for a battery or batteries with the sub50is disclosed that includes the battery charger housing150defining an enclosed chamber180and a converter contained within the battery charger housing150which converts heat to electrical energy. This embodiment of the battery charger110also includes electrical circuitry that is configured to transfer the electrical charge generated to a storage battery. The battery charger housing150may include a material causing the generation of additional power from heat. Further, various coatings within the battery charger housing150, inner chamber236, contact members232,234, or moveable element238may enhance performance. By way of example and not by way of limitation, the moveable element238discussed inFIG. 9, in one embodiment, additionally captures body heat and coverts the heat into electrical energy. This is in addition to the electrostatic charging and triboelectrical generator discussed above.

The order of execution or performance of the methods and data flows illustrated and described herein is not essential, unless otherwise specified. That is, elements of the methods and data flows may be performed in any order, unless otherwise specified, and that the methods may include more or less elements than those disclosed herein. For example, it is contemplated that executing or performing a particular element before, contemporaneously with, or after another element are all possible sequences of execution.