Patent Grant
8786113
The present application is a 35 U.S.C. §371 National Phase conversion of PCT/NO2009/000113, filed Mar. 27, 2009, which claims benefit of Norwegian Application No. 20081634, filed Apr. 2, 2008, the disclosure of which is incorporated herein by reference. The PCT International Application was published in the English language.
This invention regards a system and a method related to local energy generation for downhole tools and devices used in association with wells for the production of hydrocarbons.
Wells for the production of hydrocarbons are designed in a range of different ways, depending on many influencing factors. Such factors include production characteristics, safety, well servicing, installation- and re-completion issues, downhole monitoring and control requirements and compartmentalisation of producing zones.
Further, as wells mature, they are normally serviced using techniques known as per se on regular intervals.
Intervention services such as wireline and coil tubing are most commonly applied. The service could, as an example, be conducted for data acquisition purposes, for zone isolation or opening for production from new zones, for zone stimulation, for removal of salt deposits or to fix leakages in the wells tubular.
Common well components such as plugs and packers for isolation purposes, valves such as flow control valves or choke valves, data acquisition devices such as pressure-, temperature, flow rate and flow composition meters may be utilised in conjunction with a well, either as a part of the well completion (incorporated as part of the well's tubular) or as intervention tools (intervened in the well and in some cases left in the well, permanently or on a long term basis, attached to the well tubular using techniques as known per se).
The installation of the production tubular, including a selection of the above described components, and the wellhead is referred to as completing the well. Many of the above described devices can be installed as an integrated part of the well completion (tubular). In many cases, a selection of said devices can be remotely operated via control lines (hydraulic or electric lines). Such control lines can be hydraulic and/or electrical and/or fibre-optic lines that run all the way from the reservoir section(s) of a well to the surface.
Evolution of oil wells has entailed methods and well designs such as multi lateral wells and side-tracks and smart well completions. A multilateral well is a well with several “branches” in the form of drilled bores that origin from the main bore. The method enables a large reservoir area to be drained by means of one well. A side track well is typically an older production well that is used as the basis for drilling one/multiple new bores. Hence, only the bottom section of the new producing interval need to be drilled, hence time and costs are saved.
Smart well completions are typically applied in wells with several producing and/or injecting zones and/or wells with several bores (i.e. multilateral wells). Said smart well completions normally comprise a series of monitoring systems and/or valves incorporated as integrated parts of the production tubular, to monitor and control production from each producing interval in the well or injection into each injection interval in the well. Smart well monitoring systems and valves are normally operated remotely through hydraulic and/or electric communication (and in some cases partly fibre optic) lines that run all the way from the reservoir section(s) of a well to the surface. Often, as a backup solution, smart well valves can also be manipulated by an intervention operation (such as coiled tubing, wireline, or slickline), should the remote activation systems for some reason fail to operate. Smart well valves may comprise on/off valves (i.e. either fully open or fully shut) as well as variable opening chokes.
New well designs such as the ones described above have in a number of cases entailed a new challenge in the form of inaccessible areas of the well. In particular, this may apply for multilateral wells and sidetrack wells. It is normally deemed as non-desirable to perform interventions in the side branches of a well as the risk of getting stuck in the junction between branches and/or causing other types of damage to the well are perceived to be of too high a risk. Neither is it in most cases possible to bring control lines into branches of a well as per today. As a consequence, measurement and control tasks in branch wells are normally limited to areas where the branch enters the main bore of the well, and can normally not be executed within the branch(es) itself.
Another example of inaccessibility related to well segments is subsea wells, where the wellheads are located on the seabed. Here, interventions such as data acquisition or barrier installation jobs are scarce due to low availability and high costs associated with required drilling rigs or intervention vessels that need to be mobilised for the work.
In addition to the problem with non-accessible wells and/or areas in wells, several other factors may inflict challenges to the operation of well equipment. Such factors include debris/fill material, corrosion, scaling (salt deposits), and damage to control lines and line connectors. As an example, debris such as sand, scale (salt deposit) particles or steel fragments from drilling or perforation operations may deposit on top of intervention plugs, making it very difficult to retrieve them after usage. Scale and corrosion on a plug itself may cause similar problems.
In summary, there is a range of possible scenarios that entail non-accessibility to or non-operability of downhole tooling required for important work in wells related to oil and gas production.
To solve the said problems related to accessibility and/or operation of the above described well components new, autonomous systems and methods related to plugs, packers, valves and monitoring systems are emerging. Further, said autonomous system commonly uses wireless communication methods for communication with control systems located at the surface of the earth or at communication nodes located elsewhere in or on the wells.
Several systems are evolving that enable wireless communication in wells related to the production of hydrocarbons. One such wireless system and method is explained in detail in patent applications NO 20044338 and NO 20044339, owned by the applicant of this patent application. Further, patent application NO 20061275, also owned by the applicant of this patent application describes an alternative wireless communication technique and related applications.
A limitation with autonomous and/or wireless based downhole application is the provision of power for system operation; as all autonomous devices are dependant on local supply of power to be operated in a proper manner.
The present invention relates generally to local, downhole electrical power generation and, in a preferred embodiment describes herein, more particularly to a power generator based on flow-induced vibration principles.
Existing Methods
In order to energize downhole wireless telemetry systems and autonomous devices it is commonly accepted to utilize non-rechargeable batteries. However, such batteries entail several challenges which limit the possible use of wireless telemetry and autonomous devices:
Based on challenges described above it can be concluded that wireless telemetry systems and autonomous devices are dependant on local downhole power generation for prolonged operation as well as high temperature applications. Several methods have been patented in the industry and some are developed. However, known existing systems suffer from certain drawbacks resulting in short lifetime and/or too low energy generation levels, and may not be applicable for many autonomous systems. A selection of methods can be exemplified as follows:
Upon careful consideration, the applicant of this patent has concluded that vibration based energy generation systems are perceived to be the best option for a long-term application in a hydrocarbon well environment.
Vibration, or more precisely flow-induced vibration generators, have been investigated and patented by the industry. Patents written as far back as 1959 (U.S. Pat. No. 2,895,063) and 1971 (U.S. Pat. No. 3,663,845) describes means of generating electric power from a flowing fluid (in this case air) which causes an object designed for the purpose to vibrate, said object being connected to a energy generating device such as a magnet and coil assembly.
As a further example, the present invention has similarities to U.S. Pat. Nos. 5,839,508 and 7,199,480. However, all the above mentioned patent documents as well as other investigated publications that describe the state of such technology are perceived to have weaknesses with respect to application in a hostile and highly pressurised downhole environment as well as gaining an optimal output of electric energy.
The latter—i.e. output of electric energy in an oil well by means of a vibration assembly—has proven, through research, to be a challenging task. As an example, power output in the order of magnitude W (Watt) may be relatively hard to achieve (output in the order of mW is more likely to expect), hence it is of great importance that downhole energy generation devices are designed for as high efficiency as possible. This may not be achievable without novel, inventive design features related to vibrating based energy generation tooling as described herein.
Based on the existing knowledge from public information, such as the likes of U.S. Pat. Nos. 2,895,063 and 3,663,845, the current invention identifies novel and inventive features required for high-pressure regime, downhole operations where the output of power needs to be optimised.
The objective of the invention is to provide a novel vibration based energy generation system to add lifetime, functionality and redundancy to the operation of autonomous downhole devices.
Said autonomous downhole devices could have the function to undertake wireless communication to/from external wireless communication nodes (placed in the same well or at the surface of the earth), and perform execution of required work operations. Such work operations could be performed on associated system elements such as packers, plugs, valves, monitoring systems, and wireless telemetry systems.
An entailing objective of the invention is to provide for autonomous, preferably stand-alone downhole solutions in relation to plugs, packers, valves, monitoring systems, and wireless telemetry systems associated with wells for the production of hydrocarbons, that overcome the problems identified above, such as problems with installing and operating equipment in non-accessible areas of wells and non-accessible/malfunctioning equipment due to factors such as debris, sand, scale and corrosion.
In a first aspect of the present invention there is provided a downhole electrical energy generating device for transforming energy from a fluid flow passing the device, comprising:
In one embodiment, the invention comprises a downhole energy generation device consisting of a vibrating assembly, an atmospheric or pressure compensated compartment containing energy harvester(s) (vibration-to-electric energy converter such as a magnet/coil assembly), an active tuning device, and an electronics module connected to a rechargeable battery pack.
Further to a preferred embodiment, the vibrating assembly includes a stiff body in the form of a rod, and an elongated body also denoted “crossbar” in the following. The rod is required to connect the crossbar to the active tuning device and the pressure compensated compartment containing the energy harvester.
The crossbar is of a specific shape and geometry as required to induce an optimised vortex shedding effect as fluid flow passes the vibrating assembly. In this preferred embodiment, well fluids will flow onto and around the crossbar, and a turbulent regime, known as vortex shedding (“Von-Karman” vortices), is created along and/or downstream of the crossbar. Vortex shedding and Von-Karman vortices are well known as per se, and are associated with relatively predictable and stable oscillations (alternating pressure differential).
In another preferred embodiment, an appropriate shape and geometry of the crossbar, combined with an added feature to suppress undesired turbulence generation in certain planes, will entail that the sought, optimised Von Karman vortices will be created in a desired two dimensional plane with respect to the vibrating assembly. Hence the crossbar will be subjected to optimal alternating lift forces in said two dimensional planes and the main portion of the crossbar oscillations occurs along one axis only. In a preferred embodiment, the system device of this application comprises elements for mechanically preventing the crossbar and the vibration assembly from oscillating in any planes but the desired plane, along the desired axis.
Further, in a preferred embodiment, the added features to suppress undesired turbulence, referred to as a z-axial turbulence suppressor herein, is in the form of one or more shields attached to one or more portions of the crossbar, preferably at the end surfaces (with respect to the z-axis) of the crossbar. The purpose of the z-axial turbulence suppressor is to prevent the generation of undesired vortices in the downstream wake of the crossbar, vortices that are mostly perpendicular to the desired axis of vibration and that carry the potential to alter (reduce) the desired Von Karman vortices in the desired plane, along the desired axis, as demonstrated through recent research by the applicant of this patent.
In a preferred embodiment, an active tuning module enables the system device of this invention to change/correct the natural oscillating, frequency of the oscillating system components (vibration assembly). As an example, this could be required if changes in flow rates or flow composition entail changes in the imposed Von Karman vortexes, i.e. the fluid imposed vibration frequency. By operating the tubing module, the natural oscillating frequency of the vibration assembly could be changed to match the fluid imposed vibrations. Hereby, resonance and thereby an optimal energy harvesting process could be obtained.
In one embodiment, the active tuning module comprises one or more sensor devices for the registration of (negative) changes in system performance, such as reduced energy levels measured by means such as accelerometers readings or energy harvester output. Further, upon indication of said changes, the system possesses capabilities to change the natural oscillating frequency of the vibration assembly. In one embodiment, the active tuning module comprises an actuator operating a spring, such as a progressive spring, to change the stiffness/spring constant of the vibrating assembly, hence the natural oscillating frequency. In another embodiment, the active tuning module comprises a mass-transfer system/function in order to change the oscillating mass of the vibration system, hence the natural oscillating frequency. In one embodiment, the frequency tuning is controlled by a pre-programmed routine, based on simulations related to the given well/hardware configuration. In another embodiment, the frequency tuning is achieved by performing one/more sweeps, for instance by compressing a progressive spring from one predetermined set value to another set value, while monitoring at which compression displacement the energy output, alternatively accelerometer output is at maximum.
In one embodiment of the invention, the active tuning module is fully or partly located in a pressure compensated area of the device.
In a preferred embodiment the pressure compensated area of the device is gas filled, and the interface between the vibrating assembly and the pressure compensated area of the device is a metal process bellows. By means, a gas filled environment would impose far less damping on an oscillating magnet/coil assembly than a liquid filled environment. Further, a flexible metal bellows interface would also provide for a mechanically very flexible connection between the well regime where the vibrating assembly is located and the pressure compensated, gas filled compartment where the energy harvester is located. Again, this would contribute to optimise the theoretical energy output.
Further, for a gas filled compensated compartment, in a preferred embodiment, such compartment would be associated with a progressive/gradual gas pressure compensating system sourcing gas from an in-built high-pressure gas compartment while intervening the tooling in the well. In that manner, the flexible process bellows described above will not suffer from mechanical damage neither during installation or downhole use. An associated bleed-off system would allow also for a safe retrieval of the system out of the well.
In another preferred embodiment, parts or the whole of the energy harvester module is mounted inside the crossbar of the vibrating assembly.
In one preferred embodiment of the invention, the magnets of an energy harvester are kept static while the coils are part of the vibrating assembly. In that manner, the natural frequency of the vibration system can be reduced (as the coil is lighter than the magnet), which in many cases is beneficial with respect to tuning of fluid imposed vibration and the natural oscillating frequency of the vibrating assembly.
The rechargeable battery pack may comprise any type rechargeable battery, and in a preferred embodiment the rechargeable battery pack comprises high temperature rechargeable batteries.
In a second aspect of the present invention there is provided a method for optimising energy harvesting from a fluid flowing in a pipe, the method comprises the steps of arranging a downhole electrical energy generating device in the fluid flow, said device comprising at least one vibrating assembly influenced by the fluid flow, and at least one energy harvester influenced by the vibrating assembly, wherein the method further comprising providing the device with means for influencing the oscillation frequency of the vibrating assembly.
Typical Application and Operation
Common applications would be the operation of packers, plugs, valves, monitoring systems. In general, all downhole components requiring mechanical operation and/or communication, in particular downhole components that for some reason is or has become non-accessible for intervention tool strings or permanent communication/power lines, could be subject of the invention.
In what follows, there is described an example of preferred embodiments which are visualized in the accompanying drawings, in which:
The well 101 is described herein as being a producing well in which fluid is produced from a reservoir formation 106 into a tubular string 108, and is then flowed through this tubular string 108 to surface. However, it is to be clearly understood that the principles of the present invention may be incorporated into other types of wells and other systems, for example, where fluid is injected into a formation or circulated in the well (such as drilling operations), where fluids pass from a relatively high pressure source to a relatively low pressure source within the well, or where fluid flows from a pump or other “artificial” pressure source etc. Thus, it is not necessary in keeping with the principles of the present invention for fluids to be produced through a tubular string 108 or from a well 101.
In the well 101 as depicted in
Further,
The various devices, such as the gauge 104 and the telemetry system 103 can be electrically connected to the energy generator 105 via electric lines or conductors, integrally formed, or directly connected to each other. Furthermore, the energy generation system can be placed in any configuration to other downhole devices such as for example the packer or plug system 102, the gauge 104, and the telemetry system 103. The configuration illustrated in
In
Vortex shedding is a well known scientific phenomenon, where a physical body submerged in a flowing fluid entail a so-called Von Karman vortex street along and in the downstream wake of the submerged object. Typically, these vortices follow a relatively predictable, alternating pattern that creates resulting alternating lift forces on the submerged object, which in turn may cause the object to oscillate. The frequency of the vortex oscillation is a physical relation between velocity and physical properties of the fluid and shape/geometry of the submerged object and can be estimated with a given certainty, further to the so-called Strouhal number. In particular, the frequency of the induced vortices increases as flow velocity increase, and furthermore the frequency and strength of vortex shedding is related to the Reynolds number, Re. It is of importance that the Reynolds number is not above “Supercritical” as this will induce no vortex shedding. Furthermore, if the Reynolds number is in the sub critical range the frequency of the vortex shedding is very low.
The resulting oscillations from vortex shedding are not illustrated in
The geometry, shape and accessories related to the crossbar 206 may be optimised to generate as good an interaction with the flow 107 as possible, hence generate an optimal energy output of the downhole energy generator system. In a preferred embodiment of the invention, such optimisation is to be achieved by the aid of Computational Fluid Dynamics (CFD) simulations and/or physical testing.
The fluid flow represented by arrows 107 may include one or more liquids (such as oil, water, gas condensate, etc.) one or more gases (such as natural gas, air, nitrogen, etc.) one or more solids (such as sand, scale deposits, cuttings related to drilling, artificial sands, etc.) or any combination of liquids and/or gases and/or solids.
Furthermore to
To generate oscillating lift forces that are dominant in one axis, which is normally desirable, the main body of the crossbar 206 (the “bluff body”) could be made in the form of a rectangular shaped box or an elliptic shaped, cylindrical container, or similar (for instance a combination of the two mentioned shapes and other shapes with geometrical shapes that creates a dominant symmetry with respect to vortex shedding taking place in the direction of one desired axis). Research undertaken by the applicant of this patent application has surprisingly revealed that for “pure” bluff bodies, such as a rectangular shaped box, vortex shedding along the desired axis can be suppressed/dampened due to high-velocity flow along the “short ends” of the crossbar 206. Typically, the short ends of the crossbar will be closer to the wall of the well 101 than other surfaces of the crossbar, and as a result, fluid velocity will be higher in the section between the short ends of the crossbar and the inner wall of the well 101. Said research has revealed that the high velocity fluid streams from this area may disturb/suppress the desired vortex shedding process along the desired axis (y-axis). In other words, CFD simulations have revealed that vortex shedding in two perpendicular planes may reduce/suppress each other, and it is of importance to eliminate all vortex shedding in one of the two (the “wrong/non desired) planes to optimize the vortex shedding in the other (desired) plane such that the lift forces are maximized. To prevent the undesired vortex shedding/disturbing turbulence along the z-axis taking place in the near-wake of the crossbar, one can add one or more shields 207 to the crossbar 206. As it is of interest to produce the lift forces over the largest area of the crossbar, the shields 207 are included on the short sides of the crossbar 206 as shown in
The energy storage module 201 typically comprises 2 or more rechargeable batteries. In general, a rechargeable battery can not be charged and provide power simultaneously. Hence, a most typical configuration in a preferred embodiment of the invention comprise at least 2 rechargeable batteries, preferably more than 2 batteries in order to provide for backup should one battery cell fail, as well as a smooth, uninterrupted system operation, not being disturbed by voltage spikes at the time of changing being powered from one battery cell to another. In another embodiment of the invention, the energy storage module 201 comprises one or more capacitors. In a preferred embodiment of the invention, the capacitors are super capacitors.
The frequency of the fluid imposed oscillations 304 imposed on the arm 205 and the crossbar 206 are relying on factors such as the velocity and physical properties of the fluid and shape/geometry of the crossbar, as mentioned earlier.
Furthermore, to achieve an optimal energy output from the downhole energy generator 105, it is desired to “tune” the mechanical properties of the vibrating assembly 250 so that the natural oscillating frequency of the mechanical system to a substantial degree match the fluid imposed alternating lift forces. In a preferred embodiment, the frequency of the fluid imposed, varying lift force oscillations 304, match the natural oscillating frequency of the assembly 250 to a significant degree, so that resonance occurs and system energy is optimised. This again will entail optimal system performance with respect to energy generation, i.e. generation of electrical power.
The natural oscillating frequency of the vibrating assembly 250 is generally a function of stiffness and weight of the arm 205 and the crossbar 206. To a certain degree, a frequency match could be achieved by choosing a correct weight/stiffness relation. However, in a preferred embodiment of this invention, the natural oscillating frequency of the vibrating assembly 250 is controlled by a flexible tuning device 204, which comprise means for adjusting the flexibility/stiffness/spring constant of the vibrating assembly 250.
In a one embodiment, the flexible tuning device 204 will mechanically bias the vibrating assembly 250 towards a neutral position, radial centred, i.e. radial tension in the flexible tuning device 204 will increase as vortices are shed over the crossbar 206 and this deflects. In that way, in a preferred embodiment of the invention, the vibrating assembly will oscillate around a neutral-point, along the desired axis as described above.
In a preferred embodiment of the invention, the flexible tuning device 204 can be adjusted autonomously during operation if flow and/or fluid parameters change, such that the natural oscillating frequency of the vibrating assembly 250 to a significant degree will correspond with the fluid imposed, oscillating frequency. For this embodiment, the downhole energy generation process can be optimized at all times without having to retrieve the energy generator to surface.
In one embodiment, the flexible tuning device 204 comprise sensoring devices for the registration of (negative) changes is in system performance, such as reduced energy levels measured by an accelerometer or by direct measurement of energy harvester output by means of electric energy. Further, upon indication of said changes, the energy generator system 105 possesses capabilities to change the natural oscillating frequency of the vibration assembly 250. In one embodiment, the flexible tuning device 204 comprises an actuator operating a spring, such as a progressive spring, to change the stiffness/spring constant of the vibrating assembly, hence the natural oscillating frequency of the vibration assembly 250. In another embodiment, the active tuning module comprise a mass-transfer system/function in order to change the dominating oscillating mass of the vibration system 250, hence the natural oscillating frequency. In a third embodiment, the tuning is achieved by means of controlling the electric output from an electric tuning device, such as a generator (magnet/coil assembly) and/or applying required electric resistance to the output circuit. In a general embodiment, tuning is achieved by a combination of the above mentioned methods. In one embodiment, said frequency tuning is controlled by a pre-programmed logic routine, based on up-front simulations related to the given well/hardware configuration. In another embodiment, the frequency tuning is achieved by performing one/more sweeps, for instance by compressing a progressive spring from one predetermined set value to another set value, while monitoring at which compression/displacement the energy output, alternatively energy level (accelerometer reading) is at maximum.
As mentioned, the natural oscillating frequency of the vibrating system 250 can be determined for various geometries of the crossbar 206 and various flow and fluid parameters with aid of CFD analysis and empirical relationships guided by testing of the present invention. In relation to rigidity and stiffness of the vibrating assembly 250, for a preferred embodiment of the invention, the flexible tuning device 204 is of substantially less rigidity and stiffness than the arm 205 and the crossbar 206, such that the arm 205 is not substantially bent along its length during the vibrations 304.
A preferred embodiment of the crossbar 206 is shown in
In an embodiment that has proven to be very effective, the surfaces 403 parallel to the flow direction 107 has the largest area compared to the other surfaces 402 parallel to the flow direction. In this preferred embodiment, the oscillating lift forces 302 will act on the largest surfaces parallel to the flow 107, and the magnitude of the forces 302, which induce the vibrations 304, are maximized.
Another but less effective configuration is presented in
One embodiment of the flexible tuning device 204 is illustrated in
In a preferred embodiment of the invention the flexible tuning device 204 and/or the pressure housing 603 is filled with a gas, and the interface between the vibrating assembly 250 and the pressure compensated area of the device is a metal process bellows 601. By means, a gas filled environment would impose far less damping on an oscillating magnet/coil assembly than a liquid filled environment. Further, a flexible metal bellows would provide for a mechanically very flexible connection between the vibrating assembly 250 and a magnet/coil assembly in the embodiment where the latter is mounted inside a gas filled pressure-housing 603. Both the said factors would contribute to optimise the electric energy output.
Further, for a gas filled compensated pressure housing containing a magnet/coil assembly, in a preferred embodiment, such compartment would be associated with a progressive/gradually compensating system sourcing gas from an in-built high-pressure gas compartment while intervening the system in the well. In that manner, the flexible process bellows 601 would not suffer from mechanical damage neither during installation or downhole use. An associated pressure bleed-off system would allow also for a safe retrieval of the system out of the well.
Further to
The pressure housing 603 may or may not include both the flexible tuning device 204 and the energy harvester module 203, cf.
As explained in relation to
In one embodiment of the invention, whole or parts of the stiffness alteration device 604, as well as any other illustrated or mentioned system component, may be located outside said pressure housing 603 and/or pressure compensating device 601.
The seal device 606 may include a threaded interface, but such technology is known to one skilled in the art and is therefore not explained in further detail. Furthermore, the flexible attachment joint 602 is based on standard mechanical principles for flexible attachment of mechanical components, such as hinged joints, and is therefore not explained in further detail herein.
Another embodiment of the flexible tuning device 204 is depicted in
For the embodiment as depicted in
In a preferred embodiment, the system logic includes means for determining the optimum stiffness of the stiffness alteration device 701. As an example this can be achieved by a sweep, where the stiffness alteration device 701 will be adjusted from minimum to maximum, whilst the sensor/electronics/logic will measure resulting effect, such as energy output, and thereafter adjust the stiffness alteration device 701 to the position which yields an optimized energy generation (as explained in relation to
Even another embodiment of the flexible tuning device 204 is depicted in
For the embodiment as depicted in
In
During system operation, the guide 903 is fixed at a predetermined position on the arm 205, said position is preferably determined by requirements to free end amplitude and the tuning with respect to frequency of the fluid imposed oscillations 304. Further, during operation, the oscillating arm 205 will be guided back and forth between the adjustable counteractive devices 902, whereas the adjustable counteractive devices 902 bias the oscillating arm towards neutral (centered) position inside the guide housing 901. In similar manners as described in earlier sections, the natural oscillating frequency of the system can be changed utilizing the adjustable counteractive devices 902.
In one embodiment the stiffness alteration device 701 can be designed to generate electrical energy, hence become a part of the direct energy harvesting process. This can be achieved by making the guide 903 partly or fully of a magnetic material, and mount electric coils within the guide housing 901 or vice versa. Such a system module can both serve the function as a partial energy harvester of the system and perhaps more importantly, be used to actively tune the natural oscillation frequency of the vibration assembly 250. The methods for energy generation utilizing a magnet and coil are well known for one skilled in the art and are therefore not shown in
According to an embodiment of the present invention depicted in
In this embodiment, the energy harvester module 203 comprises an energy harvester 1001, defined as a mechanical-to-electrical energy converter (such as a magnet/coil assembly) herein, which is attached to the free end of the arm 205 that is inside the housing 603.
In this embodiment, the energy harvester 1001 comprises a housing 1002 filled with a fluid 1004, and internal components 1003. The energy harvester 1001 may be based on a magnet and coil principle, but any type harvester which utilizes an oscillating motion to generate energy will be applicable. As such harvester technology exists and is readily available in the market, the harvester 1001 of
In one embodiment, the housing 1002 is omitted, and the internal components 1003 (the electric energy generating part of the harvester 1001) are exposed to the same internal fluid, pressure and other parameters as are present inside the pressure housing 603. Further, in one embodiment, at least parts of the internal components 1003 are fixed to the housing 603. As an example, a magnet/magnets could be attached to the arm 205 and a coil/coil assembly attached to the pressure housing 603 body. In a preferred embodiment of the invention, the coil element(s) is attached to the oscillating parts of the system, whereas the magnet element(s) is attached to a fixed, static part of the system such as the pressure housing 603 body.
To summarise, for the embodiment as depicted in
Another preferred embodiment of the invention is depicted in
A significant benefit with the embodiment depicted in
In another embodiment, energy can be generated both in the crossbar 206, stiffness alteration device 701, and in a harvester mounted at the opposite end of the arm 205 of the crossbar 206, or in any combination of 2 of said locations. One example of such is presented in
In
For this embodiment, the electronics circuit board 1302 is connected to a rechargeable battery pack 1304 via communication lines 1303, and the rechargeable battery pack 1304 is connected to a task execution device (not depicted in
An alternative embodiment of the present invention is shown in
The well 101 is described herein as being a producing well in which fluid is produced from a formation 106 into a tubular string 108, and is then flowed through this tubular string to surface. However, it is to be clearly understood that the principles of the present invention may be incorporated into other types of wells and other systems, for example, where fluid is injected into a formation or circulated in the well (such as drilling operations), where fluids pass from a relatively high pressure source to a relatively low pressure source within the well, or where fluid flows from a pump or other “artificial” pressure source etc. Thus, it is not necessary in keeping with the principles of the present invention for fluids to be produced through a tubular string or from a well.
In the well 101 as shown in
Further,
The various devices, such as the gauge 1403 and the telemetry system 1402 can be electrically connected to the annular type energy generator 1401 via electric lines or conductors, integrally formed, or directly connected to each other. Furthermore, the annular type energy generation system 1401 can be placed in any configuration to other downhole devices such as for example the gauge 1403, and the telemetry system 1402. The configuration illustrated in
A preferred embodiment of the annular energy generator 1401 is illustrated in
The fluid flow 107 may include one or more liquids (such as oil, water, gas condensate, etc.), one or more gases (such as natural gas, air, nitrogen, etc.), one or more solids (such as sand, scale deposits, cuttings related to drilling, artificial sands, etc.) or any combination of liquids and/or gases and/or solids.
Further to
Further to
The frequency of the oscillations 1507 of the arms 1505 and the crossbars 206 are controlled by factors as described earlier herein. Further, all components described for the other non-annular applications may be incorporated partly or fully in the annular application, too. For instance, flexible tuning devices 1504 may be included to tune the natural oscillating frequency of the mechanical system with respect to the frequency of the fluid imposed oscillations. In one embodiment, the flexible tuning devices 1504 can be adjusted autonomously during operation if flow and/or fluid parameters change.
Further to
To overcome the above described challenge,
The pressure compensation module 1800 comprises a high-pressure chamber 1804. Typically, this chamber is purged with a high pressurised gas 1805 such as nitrogen prior to intervention and installation in the well. Further, pressure equalising device 1800 comprises a work chamber comprising an upper section 1806 and a lower section 1809 separated by a piston 1808. The upper section 1806 of the working chamber is in fluidic contact with the internal fluid 605 of the energy harvester 203 via the channel 1807. The lower section 1809 of the working chamber is in fluidic contact with the well fluid via the channel 1810. Do note that channel 1810 may include filters, fluid velocity reducers and other features to compensate for the fact that it will be exposed to well fluid that may carry impurities. The piston 1808 is connected to pilot valve 1811 via a shaft 1812. Further, the piston 1808 is being pushed/biased in the direction of the lower section 1809 of the working chamber by a spring 1813 towards end stop profile 1816. In a preferred embodiment of the invention, the spring force causes the pilot valve 1811 to be and remain in a shut position when pressure in the upper section 1806 of the working chamber equals the pressure of the tool surroundings (i.e. atmospheric conditions when at surface and well pressure surroundings when submerged in the well). Further, according to a preferred embodiment of the invention, the spring is compressed so that the pilot valve 1811 opens when a given overpressure exists in the lower section 1809 of the working chamber with respect to the upper section 1806. In one embodiment of the invention, a pressure differential in the range 1-20 psi is required to open the pilot valve 1811. When the pilot valve opens, compressed gas 1805 will flow from the high pressurised chamber 1804 into the upper section 1806 of the working chamber, and from there into the energy harvester module 203 via the channel 1807. This causes a pressure increase to take place in the upper section 1806 of the working chamber as well as in the internal fluid 605 of the energy harvester module 203. As said pressure increase causes the pressure differential between the upper section 1806 and the lower section 1809 of the working chamber to drop below a given set-value (as defined by means of a pre-adjusted spring force) the pilot valve 1811 will close. In a preferred embodiment of the invention, the described mechanisms will provide for a smooth, gradual gas pressure increase in the energy harvester module 203 as a function of submerging the tooling into a well.
In a preferred embodiment of the invention, the gradual pressure purging/equalising process as described herein will entail that the energy harvester 203 can be filled with a gas rather than a liquid, hence minimise liquid dampening impact on the energy generation process itself. Further to a preferred embodiment, the purging/equalising system will allow for the use of a very flexible pressure compensating device 601, allowing for optimised flexibility/freedom of the oscillating parts of the system. Further to a preferred embodiment of the invention, no significant damage or reduction in physical properties is imposed on the pressure compensation device 601 as a result of the functionality provided by the pressure equalising device 1800, meaning that the pressure compensation device 601 will be capable of handling any pressure differences created by the pressure equalising device 1800 during normal operation.
Further to a preferred embodiment of the invention, check valves 1814, 1815 are included in the system in order to allow for a safe retrieval of the tooling, i.e. bringing it from a high pressurised well condition to an atmospheric condition at the surface of the earth. In a preferred embodiment of the invention, said check valves are adjusted to open at a given overpressure. In one embodiment of the invention, said overpressure is in the range 1-30 psi. Further, said valves may have a function to avoid malfunction due to overpressure in the system should the pilot valve 1811 start to leak.
In another embodiment of the invention, said pilot valve 1811 and check valves 1814, 1815 could be replaced or supplemented with alternative valve designs, including such as solenoid valves and similar that could be operated by means such as logic functions steered by a micro controller based on appropriate sensor input, such as pressure sensor input.
In one embodiment of the invention, alternative pressure equalising devices 1800 can be utilised without departing from the idea of this invention.
As can also be seen from
The invention shown in
In one embodiment of the invention, the flow alteration device 2000 has the capability to create alterations in multiphase flow comprising a combination of at least two of the components oil, gas and water in order to obtain an optimal energy generation process. In one embodiment of the invention, said flow alteration device 2000 for multiphase flow include system elements to separate the fluid phases, such as to separate the gas phase from a fluid phase, so that energy can be harvested from one single phase fluid flow, or multiple single phase fluid flow streams, respectively. In one embodiment, said system elements to separate the fluid phases comprise active or passive systems for creating a centrifuge/cyclone effect on the multiphase fluid. In another embodiment, said system elements may comprise profiles that make the flow laminar and subsequently separates it by means of gravitational forces, or a combination of methods as described herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20081634 | Apr 2008 | NO | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/NO2009/000113 | 3/27/2009 | WO | 00 | 11/8/2010 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2009/123466 | 10/8/2009 | WO | A |
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| Number | Date | Country | |
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| 20110049901 A1 | Mar 2011 | US |
