RU2244995C1 - Electric generator for feeding borehole equipment - Google Patents

Abstract

FIELD: electrical engineering; power supplied to borehole loads.

SUBSTANCE: proposed generator is characterized in that radial-axial bearing disposed at end of post on one end of stator is built of two bearings, one axial and one radial bearings, with flexible member inserted between part of frame and outer ring of one of these bearings, that additional radial bearing is installed on post at other end of stator, stuffing assembly of stator frame is disposed between end section of its movable part and post, and that it has end seal, annular cavity with radial-end collar and lubricant, as well as impeller, all mounted in tandem from additional bearing on butt-end of frame movable part.

EFFECT: enhanced reliability of generator protection against external adverse impacts.

1 cl, 2 dwg

Description

The invention relates to stand-alone power sources for downhole consumers (mainly telesystems) when drilling directed oil and gas wells.

It is a well-known design [1] of an autonomous power supply that converts fluid energy into electricity, made on the basis of an alternating current generator with permanent magnets of a rotor-inductor, on the axis of which a turbine is placed. The design is equipped with a shell (housing) with channels for supplying and exiting fluid.

Also known is the design [2] of an autonomous power source that converts the energy of a fluid into electrical energy, containing a turbine and a generator located in the internal cavities of the housing, which has input and output channels with spring-loaded check valves installed in the channels.

However, for the power supply of deep (downhole) telemetric systems, the use of well-known structures without significant modifications to the nodes and elements is practically impossible, since a number of technical conditions, determined by the specifics of drilling operations during well construction, are not taken into account, namely:

- temperature fluctuations in storage and operating conditions are up to 130 ° С (from - 40 ° С to + 90 ° С);

- intense corrosive erosion of the wash fluid due to the high content of water-soluble minerals and chemicals, as well as abrasive particles in combination with significant speeds around the body;

- high absolute pressure values of volumetric (comprehensive) compression under conditions of deep immersion in the aforementioned medium with significant, up to 10% of absolute values, pressure fluctuations (pulsations);

- intense vibration of arbitrary orientation during the work of the rock cutting tool along the bottom, transmitted to all nodes and structural elements, since it is part of the “layout of the bottom of the drill string” (the so-called BHA);

- severe restriction on dimensions (diameter and length) while ensuring the necessary power supply;

- the impossibility of prompt troubleshooting and / or adjusting operating conditions (etc., etc., etc.), since the structure is used at significant (up to 5000 m) depths, and the process of its extraction for examination, repair and / or replacement is very time consuming and expensive.

As shown by practice, the above-mentioned operating conditions are partially satisfied by the design [3], which contains a hydraulic turbine and an electric generator, the rotor shaft of which is connected to the hydraulic turbine shaft by means of a coupling for transmitting torque to the hydraulic turbine shaft. The electric generator consists of a rotor with permanent magnets and a stator with windings, while a thin-walled steel cup is placed in the gap between the stator and the rotor, and the gap between this cup and the rotor is filled with oil-based ferromagnetic fluid.

However, the significant drawbacks of the aforementioned design include the fact that during the operation of its rubber-metal supports, progressive backlash formation occurs in friction pairs, and the initially dense (tight) assembly of these pairs in the object leads to non-start of the source. The total fluid flow from above, through the channel of the drill pipe, is divided into two in the object during the flow around the generator, and only then goes (with intense vortex disturbances) to the turbine, which is subjected to increased vibrational effects together with the cantilever-bearing shaft, which does not contribute to the durability of rubber-metal bearings having a fairly small resource for health. A turbine (or a set of turbines), as well as a rotor in the generator housing, is located on the rotor itself cantilever, that is, at a certain distance from the rotor bearing assembly closest to it, which also reduces the resource of operability of the whole object. The initial (initial) introduction of a ferromagnetic fluid into the stator-rotor gap is also quite complicated technologically. It should also be noted that, in light of the above requirements for a deep power source of a similar design, the ferromagnetic fluid in the stator-rotor gap is not protected against oil loss, since the annular cavity of the gap at the ends is not closed, and the ferromagnetic particles are aggregated (at rest liquids with a stationary rotor) at the poles; Moreover, their distribution in the oil volume is very heterogeneous, and where the oil is depleted in the content of magnetic particles, it can be squeezed out by pressure drops between the ends of the annular cavity of the “rotor-stator” gap.

The closest technical solution - the prototype - is an object according to a security document [4] of the Russian Federation, containing a composite of moving (rotating) and fixed parts, a housing, the fixed part of which contains a coaxial mount in the channel of any downhole pipe string to allow flow the housing, as well as electrical outputs (electrical connector) for connecting to a consumer device (tele-system) and is made in the form of a cantilever axis-rack. The stator windings and the moving part of the housing are placed on this axis-rack; the latter is coupled to the axle-strut by means of rolling bearings, provided with a rotor-inductor inside, the turbine is rigidly fixed on the outside, and the cavity between both parts of the housing is closed by a sealing unit.

It should be noted that the coupling of the movable part of the housing with its stationary part by means of a bearing-bearing assembly from a sequence of three rolling bearings, one of which is roller (with conical rolling bodies) and the implementation of the sealing unit of the housing cavity in the form of two ring-shaped seals in the coaxial gap between the housing parts provides satisfactory performance of the object as a whole at angles of deviation of the barrel from the vertical — when driving a well — no more than 30 ... 40 degrees, but with large deviations the trunk from the vertical, the object’s performance, as practice has shown, is insufficient. Note, moreover, that the ring-shaped seals of plastic-viscous material such as fluoroplastic do not have the function of an additional radial bearing-support between both parts of the housing, they only seal its cavity and damp - in some limits - the radial runout of the moving part of the housing when it rotates around axis racks. We also note that with increasing penetration depths of directional and horizontal wellbores, adverse factors affecting the object progress, and very significantly.

The aim of the invention, that is, the required technical result, is to ensure the protection of the object from adverse factors, especially from the penetration of the drilling fluid into the cavity of the housing, and with a significant, to horizontal, deviation of its spatial position from the vertical; otherwise, an increase in consumer properties.

This goal is achieved by the fact that in the object - according to the prototype - containing a composite of movable and fixed parts, a housing, the fixed part of which contains a coaxial mount in the channel of any downhole pipe string to allow flow around the housing, as well as an electrical connector (electrical leads) for connection with a device, for example, with a telesystem, and is made in the form of a cantilever axis-rack, on which the stator windings and the moving part of the housing, which is interfaced with the axis-rack, are placed the shaft of the angular contact bearing assembly to provide rotation, is equipped with a coaxial stator with a rotor-inductor, the turbine is rigidly fixed on it from the outside, and the cavity between both parts of the housing is closed by a sealing assembly, on one side of the stator, at the end of the axis the bearing unit is made in the form of two thrust and radial bearings with an elastic element between the movable part and the outer ring of one of these bearings, on the other side of the stator on an axis-pillar is installed an integral radial bearing, a housing cavity sealing unit is located between the end portion of its movable part and the axis of the strut and contains, sequentially from an additional radial bearing, an end seal, an annular cavity with a radial-end seal and lubricant, as well as an impeller at the tip of the movable part of the housing.

Note that from the well-known sources of information (including patent), devices that are identical to the proposed and / or devices with a combination of essential features (including distinctive ones) that are equivalent to the essential features of the proposed technical solution and exhibit the same new properties are not identified allowing to achieve the required technical result during implementation. This allows us to argue that the proposed technical solution meets the "criteria" of the invention.

In the drawing, figures 1 and 2, shows a General view of the generator with a longitudinal section along the diametrical plane.

An electric generator for supplying downhole devices comprises a composite housing of a movable (position 1) and fixed (position 2) parts. Part 2 of the housing is equipped with a node 3 for coaxial fastening in the channel of any pipe string (shown in the drawings as a thin line, conditionally, and is not indicated by a separate position). A similar installation of an object in a well allows it to flow around the wellbore fluid. This fixed part 2 of the housing is made in the form of an axis-rack, on which the electrical connector 4 for connecting the consumer, the stator winding 5, the angular contact bearing assembly 6 and the movable, rotatably, housing part 1 are placed. A rotor-inductor 7 enclosing the stator 5 is placed inside this part, and a turbine 8 is fixed on it outside. The cavity 9 between the two parts of the generator is closed (closed) from the external environment by the sealing unit 10. The angular contact bearing assembly 6 is placed between the end 11 of the axis of the rack and the movable part 2 of the housing, made in the form of a thrust bearing 12 and a radial bearing 13, the rings of the same name are fixed, respectively, the inner rings are at the end 11 of the axis columns, and the outer rings are placed in the moving part of the housing. Between the ring of one of these bearings and the movable part of the housing is an elastic element 14 in the form of, for example, a disk spring. On the other side of the stator 5, an additional radial bearing 15 is placed between the housing parts, behind which there is a sealing unit 10 of the cavity 9, which contains, sequentially from this bearing, an end seal 16, equipped with, for example, elements of high hardness ground to each other, an annular cavity 17 with a radial-end cuff 17 located therein from, for example, a metal-reinforced elastomer, the cavity 9 being filled with grease (not indicated in a separate portion). At the tip 20 of the movable part of the housing, an impeller 19 is made in the form of, for example, radial channels for rejecting solid ones having, as a rule, a higher density (than liquid) from the generator.

An electric generator for feeding downhole devices works according to a well-known principle, but before it can be operated in deep extreme conditions, it must be installed and fixed in the central channel of any element (see Fig. 1) of the pipe string as shown or by any other well-known way. Naturally, the generator with its sealed leads (see figure 1, item 4) of the stator power windings must be connected to the consumer. During the penetration of the barrel, some of the hydraulic energy of the wash fluid stream is taken away by the turbine and converted by the generator into electrical energy. The next time the drill string is removed, it is easy to carry out a control inspection (examination) of the device and, if necessary, replace its external part (turbine with a rotor-inductor) with a similar one, but with different parameters, or replace it entirely.

In connection with the foregoing, the proposed generator for powering downhole devices provides the required technical result when using it, meets the criteria and requirements of inventive law for the object of the invention, and is subject to protection by the relevant protection document of the Russian Federation according to the application.

Sources of information

1. Pneumatic shaft lamp, M., GTTI, Mining Journal, 1958, No. 3.

2. USSR, description of the invention No. 1379880, M.cl. ⁴ H 02 K 7/18, 1986.

3. USSR, description of the invention No. 1805530, M.cl. ⁵ E 21 B 47/022, 1990.

4. RF, description of utility model No. 11936, M.cl. ⁶ H 02 K 5/12, E 21 V 47/022, 1999, prototype.

Claims (1)

An electric generator for powering downhole devices, comprising a housing composed of a movable and fixed parts, the fixed part of which contains a coaxial mount in the channel of any downhole pipe string to allow flow around the housing, as well as an electrical connector for connecting to the device, for example, with a television system, and in the form of a cantilever axis-strut, on which the stator windings and the movable part of the housing are located, which is interfaced with the axis-strut by means of an angular contact bearing To ensure rotation, the assembly is equipped with a rotor-inductor inside the coaxial stator, a turbine is rigidly fixed on the outside, and the cavity between both parts of the housing is closed by a sealing assembly, characterized in that an angular contact bearing assembly is installed on one side of the stator at the end of the axis made in the form of two thrust and radial bearings with an elastic element between the moving part of the housing and the outer ring of one of these bearings, on the other side of the stator an additional axis is installed a radial bearing, a housing cavity sealing assembly is located between the end portion of its movable part and the axle-strut and contains sequentially from an additional radial bearing a mechanical seal, an annular cavity with a radial-end seal and lubricant, as well as an impeller at the tip of the movable housing part.

Images