RU2417313C1 - Generator of power supply for borehole equipment - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: permanent magnets are mounted on stationary axis of generator. An exciting coil is installed inside the protective case of the generator. A generator rotor is made with alternate magnet-transparent and magnet non-transparent elements. The rotor is positioned between the stationary axis and exciting coils and is connected to a hydro-turbine. Also, the hydro-turbine is installed in the front part of the generator. Two attachment points facilitating flow of drill agent are made on the protective case. Straightening vanes spinning flow of drill agent after the hydro-turbine are arranged inside the first attachment point. Wires from the exciting coil to an electrical connection run through orifices made in the protective case. An internal cavity of the generator is filled with lubricating liquid. Passage for lubrication filling is made on top, while the electric connection is made beneath. The electrical connection is coaxial. A drain hole closed with a plug is made in a lower part of the protective case.

EFFECT: increased capacity of generator at decreased diametre dimension and weight.

8 cl, 3 dwg

Description

The invention relates to electric machines. Specifically, the invention is intended for a downhole power generator and a downhole telemetry system transmitter. The generator converts the energy of the flushing fluid into electrical energy, which is necessary to power the downhole navigation and geophysical instruments during drilling and the transmitter of the electromagnetic communication channel. For the telemetry system to work at great depths, an increase in the power of the transmitting device to 1 kW or more is required. To get more power with the small dimensions of the generator is very problematic.

A known alternator for powering the telemetry system during the drilling of small diameter wells, including a fixed internal stator with a collector and an external rotor mounted on the drive shaft, equipped with electromagnets (RF patent No. 2060383, MKP ЕВВ 47/022, 47/00, priority from 21.02 .92 g.). The lubrication system is a cavity between the rotor and the stator, filled with lubricating fluid.

A self-contained turbine unit (electric generator), also designed to supply electric energy to the telemetry system, containing a hydraulic turbine driven by a wash fluid stream, an oil-filled stator filled with an epoxy compound, and a rotor of an alternating current generator with permanent magnets located on the same shaft with a hydraulic turbine ( Molchanov A.A., Siraev A.X., “Borehole autonomous systems with magnetic recording”, M., Nedra, 1979, pp. 102-103).

This generator consists of a stator located inside the unit and a six-pole annular magnetic rotor made from the outside. The rotor is also a casing for the working blades of a three-stage hydraulic turbine. In front of each stage of the working blades of the hydraulic turbine, in turn, there are three stages of guide vanes assembled on the outer casing, which increases the diameter of the device. To prevent the flushing fluid from entering the generator and the bearing units, sealing devices are installed, the internal cavity of the generator is filled with transformer oil.

Due to the fact that the generator operates in the temperature range from -40 to + 130 ° C, at drilling depths of up to 3500 m or more, and the oil volume changes with temperature, a pressure compensator and thermal expansion of the lubricating fluid (oil) are introduced. The compensator for pressure and thermal expansion of the lubricating fluid is made inside the inlet fairing of the generator. It consists of two thin profile plates, one of which is convex and the other is concave. The compensator for pressure and thermal expansion of the lubricating fluid is designed to compensate for changes in the volume of oil in the oil-filled cavity of the generator under operating conditions with increasing temperature, as well as equalizing the pressure inside and outside the generator.

The disadvantages of this generator are:

- low reliability

- small resource

- large dimensions and mass of the device,

- the complexity of the design.

These shortcomings are caused, first of all, by the fact that a multistage turbine with guide vanes is used as a drive. The use of a hydraulic turbine with guide vanes as a drive places high demands on the quality of cleaning the washing liquid from fractions of drill cuttings and foreign objects, the ingress of which into the gap between the working and guide vanes of the hydraulic turbine can cause it to stop (jamming). The presence of guiding devices of a hydraulic turbine increases the diametrical dimension of the electric generator, which is undesirable when drilling wells of relatively small diameter.

The second design flaw is the complexity and unreliability of the pressure compensator and thermal expansion of the lubricating fluid. Due to the elasticity of the walls of the compensator, the pressure of the lubricating fluid is always less than the pressure of the environment. This can result in flushing fluid entering the generator’s lubrication system and in the wear of bearings, seals and other parts.

Also known generator according to US Pat. RF №2173925, the main feature of which can be considered a lubrication system. The lubrication system of this generator contains a filling device at its front end, a cavity between the external rotor and the stator, filled with lubricating fluid, and a pressure compensator and thermal expansion of the lubricating fluid located on the side of the generator mounting device, made in the form of a piston mounted with axial movement and seals mounted inside the piston with the possibility of axial movement with it. The disadvantage of this device is the difficulty of filling the system with lubricating fluid and a low seal life.

Known power generator telemetry systems according to St. RF number 34638.

This electric generator contains a filling device in its front part, a cavity between the external rotor and the stator filled with a lubricating fluid, and a compensator for pressure and thermal expansion of the lubricating fluid located on the side of the generator mounting device, made in the form of a piston mounted inside the rotor with axial movement and seals, installed, in turn, inside the piston with the possibility of axial movement with it, the piston is made with the possibility of drainage lubricating fluid in a fully charged position in the gap between the rotor and the generator mount.

The disadvantage of this lubrication system is that due to the combination of the functions of the compensator and the seal, their life is reduced.

Known generator for St. RF №13123, which contains a rotor with a turbine, a stator, a mounting unit and a reservoir for the reserve supply of lubricating fluid, made in the form of a cup made in the front of the generator with a spring-loaded piston installed inside and a refueling device. The generator and turbine are significantly distant from each other in the axial direction and are separated by a magnetic coupling, which increases the dimensions of the generator and reduces the reliability of the lubricant.

A known generator according to the patent of the Russian Federation for invention No. 2264537, comprising a protective housing with field windings, a mounting unit, a rotor with a shaft, magnets and a turbine installed through bearings in the housing, and a reservoir for the reserve supply of lubricating fluid in the form of a cup made in front of the generator with a spring-loaded piston installed inside and a refueling device, characterized in that at least one front bearing is mounted in a sleeve that is centered in the protruding part of the housing closed on the other Torons axis fixed against rotation and having an annular groove for winding and a cylindrical protrusion in the inner bore of which is mounted on at least one rear bearing and the inside shaft provided with a through axial aperture. An adjustment washer is installed between the front bearing and the rotor. Field windings are installed in the housing and are fixed with pins against bias. The spring is partially placed inside the piston. The filling device is made in the form of a valve installed in the stem channel, closed by a plug. The filling device is made in the form of a valve installed in the stem channel, closed by a plug.

Disadvantages: insufficient power of the generator with limited diametrical dimensions.

A well-known power generator for downhole equipment according to the patent of the Russian Federation No. 2333353, prototype. This generator comprises a protective housing, at least one attachment point, a fixed axis, a rotor connected to a hydraulic turbine, permanent magnets, a field winding and an electrical connector.

Disadvantages: low generator power due to the fact that the rotor speed is small 500 ... 1000 rpm. An increase in the rotor speed due to the use of the multiplier will lead to an increase in its weight and dimensions.

The tasks of its creation: increasing power while reducing the diametrical dimensions and weight of the generator.

The solution to this problem was achieved due to the fact that the power generator of the downhole equipment, comprising a protective housing, at least one attachment point, a fixed axis, a rotor connected to a hydraulic turbine, permanent magnets, an excitation winding and an electrical connector, is characterized in that the permanent magnets mounted on a fixed axis, the field winding is installed inside the protective housing, the rotor is made of alternating magnetically permeable and magnetically tight elements and is installed between the fixed axis and the windings ozbuzhdeniya. A hydraulic turbine is installed in front of the generator. Two attachment points are made on the protective casing, providing passage of the drilling fluid, while inside the first attachment point, blades are installed that untwist the flow of the drilling fluid after the turbine. The wires from the winding to the electrical connector pass through holes made in the protective housing. The internal cavity is filled with lubricating fluid. In the lower part of the protective casing a drainage hole is made, closed with a stopper. The lubricant filling hole is made at the top, and the electrical connector is at the bottom. The electrical connector is coaxial.

The invention is illustrated in figure 1 ... 3, where:

figure 1 shows the assembly drawing of the generator,

figure 2 shows a section aa,

figure 3 shows a view of B.

The power generator of the downhole equipment (figure 1 ... 3) contains a protective housing 1, at least one attachment unit, designed for installation in a drill pipe string. A generator with two attachment points 2 and 3 is shown as an example. In addition, the generator contains a fixed axis 4 and a rotor 5 connected to a hydraulic turbine 6, permanent magnets 7, an excitation winding 8, and an electrical connector 9. The permanent magnets 7 are mounted on a fixed axis 4, the field winding 8 is installed inside the protective housing 1, the rotor 5 is made of alternating magnetically permeable and magnetically impermeable elements 10 and 11, respectively, and is installed between the fixed axis 4 and the field winding (s). 8. The rotor 5 is mounted on bearings 12 and 13. The bearing 12 is sealed with a seal 14.

Hydroturbine 6 can be installed in front of the generator. Two attachment points 2 and 3 can be made on the protective casing 1, allowing drilling fluid to pass, while inside the first attachment point 2, spinning vanes 15 are installed that untwist the flow of the drilling fluid after the turbine 6. The wires 16 from the field winding 8 to the electrical connector 9 pass through holes 17 made in the protective housing 1. The internal cavity 18 of the generator is filled with a lubricating fluid. In the lower part of the protective housing 1 there is a drainage hole 19 closed by a plug 20. The hole for filling the lubricating fluid 21 is made from above and plugged with a screw 22. The electrical connector 9 is made from the bottom. The electrical connector 9 can be made coaxial.

When the generator is operating, the drilling fluid passes through a hydraulic turbine 6, which begins to rotate with a rotor 5 having alternating magnetically permeable and magnetically impermeable elements 10 and 11, respectively, which rotate and, crossing the magnetic fields created by the permanent magnets 7, create alternating magnetic fields that affect field winding 8, in which an electric current occurs. After the turbine 6, the drilling fluid passes through the spinning blades 15.

The proposed design will simplify the assembly of the generator, increase the frequency of the generated current, its voltage and current strength and, as a result, power. It also became possible to significantly reduce the diametrical dimensions of the generator or increase its power by about 2 times with the same dimensions and weight. This will allow the design of downhole tools for small diameter drill and casing. The use of wires for the transmission of electrical energy, located in the holes 17 of the protective housing 1, will allow you to output significant power without the use of sliding current collectors. The generator with the downhole tool of the downhole telemetry system can be installed in a drill or casing assembled from pipes up to 10 ... 12 m long, i.e. the length limit is not critical, unlike the diameter limit. Layout diameter: generator-downhole tool is strictly limited by the diameter of the string. Electricity is transmitted through wires 16 from the field winding 8 to the electrical connector 9. It is preferable to make the electrical connector 9 coaxial, this will eliminate the angular orientation of the electric generator inside the drill string or casing when it is docked with the downhole tool (in FIGS. 1 ... 3 the downhole tool does not shown). The generator is equipped with a pressure compensator (pressure compensator in figure 1 ... 3 is not shown).

The application of the invention allowed:

1. To increase the voltage, current, frequency, and therefore the power at the electrical terminals of the generator through the use of a rotor and alternating magneto-permeable and magnetically impermeable elements.

2. Reduce the dimensions of the generator at constant power.

3. Simplify the design of the generator.

4. To simplify the assembly and disassembly of the generator by performing a modular design and the use of a coaxial electrical connector.

5. Simplify and facilitate electrical wiring, as wires connect the non-rotating field windings to the electrical connector on the protective casing and pass inside the protective casing, which eliminates their damage during operation.

6. Solve the problem of unloading a significant axial force.

7. Improve maintainability of the generator due to the extremely simple design, the minimum number of parts and the simple configuration of all parts.

Claims (8)

1. The power generator of the downhole equipment, comprising a protective housing, at least one attachment point, a fixed axis, a rotor connected to a hydraulic turbine, permanent magnets, a field coil and an electrical connector, characterized in that the permanent magnets are mounted on a fixed axis, field coil installed inside the protective housing, the rotor is made of alternating magnetically permeable and magnetically impermeable elements and is installed between the fixed axis and the field windings. 2. The generator according to claim 1, characterized in that the turbine is installed in front of the generator. 3. The generator according to claim 1 or 2, characterized in that on the protective casing there are two attachment points that allow the passage of drilling fluid, while straightening vanes are installed inside the first attachment point to spin the flow of the drilling fluid after the turbine. 4. The generator according to claim 1 or 2, characterized in that the wires from the winding to the electrical connector pass through holes made in a protective housing. 5. The generator according to claim 1 or 2, characterized in that its internal cavity is filled with a lubricating fluid. 6. The generator according to claim 1 or 2, characterized in that in the lower part of the protective housing there is a drainage hole closed with a stopper. 7. The generator according to claim 1 or 2, characterized in that the hole for filling the lubricating fluid is made on top and the electrical connector is on the bottom. 8. The generator according to claim 7, characterized in that the electrical connector is made coaxial.

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