Method to transfer information from well along electromagnetic communication channel and device for its realisation
SUBSTANCE: method to transfer information from a well consists in the following: using a surface generator, electrical current is excited in a string of metal pipes, which generates electromagnetic field spreading in the rock of the well, which reaches the bottomhole area and creates the difference of potentials between the metal string and its isolated part. Receipt of information from the bottomhole is carried out depending on modulation of the voltage value required for stabilisation of the surface generator DC. The surface generator is a source of a stabilised DC. Besides, the surface generator is connected with one clamp to a surface part of the pipe string, and by the other one - to a grounded electrode that is remote from the well head. At the same time for transfer of information from the bottomhole the lower and upper parts of the string are closed or opened, changing the efficient value of conductivity between the grounding electrode of the current source and the metal string. When the key is closed, the specified efficient conductivity increases, and voltage on the current source clamps reduces and is recorded by a recording unit. By variation of the measured voltage the parameters of the drilled bed are decided.
EFFECT: increased reliability of information transfer from a bottomhole and expansion of its application area.
2 cl, 1 dwg
The alleged invention relates to the field of information transfer from the borehole, for example, logging while drilling, and is intended for transmission of measurement signals from the well to the surface electromagnetic communication channel.
There is a method of creating electromagnetic communication channel, which consists in the excitation of the electric current in the column of metal tubes separated by a dielectric insert, and registration on the surface of the induced potential difference between the column of drill pipe and a remote point from the wellhead. This induced potential is modulated appropriately coded signal (information), but are required for the excitation current energy is generated on the face by a downhole generator, discharging of the power flow of washing fluid generated by the drilling pump (Molchanov, Gsanremo. Wireless system for studies of oil and gas wells (theory and practice). / Under the General editorship Have. - Moscow, JSC "VNIIEM", 2003).
The disadvantages of the method are unstable signal magnitude associated with the changing conditions of the currents in soils and limited downhole power generator, and the inability to use bezzabotnov (borehole) energy source that limits the scope ol the application system.
The known method of transmission/reception geophysical data during the drilling of the wireless electromagnetic communication channel from downhole to the surface (U.S. Pat. Of the Russian Federation No. 2273732, prior. 21.05.2004, publ. 10.04.2006).
In the known method modulate the voltage generating signal to the surface by connecting the poles of land generator respectively to the string of drill pipe and a remote point from the wellhead and downhole electric dipole carry out signal ground of the generator. Allocate a clock frequency of ground generator and synchronous with her commute the encrypted message, the electric dipole on the bottom. At the wellhead measure the current generation by highlighting pulsations using synchronous detection. Measured at the mouth of the magnitude of the ripple current caused by the switching of the electric dipole on the face, judge geophysical parameters to be drilled formation on the surface. The frequency of ground generator on the surface change for better conditions of signal reception on the face.
The disadvantage of this method is that it assumes, in the electric dipole receiver signal from a ground-based generator, which determines the frequency at which the electric dipole should be switched, the signal may disappear (salt is replaster) and distorted with the passage of weakly conductive layers, and reliability of communication falls. In addition, it complicates the design of an electric dipole.
The task of the group of inventions is to improve the reliability of information transmission from downhole electromagnetic communication channel and extending the scope of its application.
This task is solved in that in the method of transmitting information from wells in the electromagnetic channel, including the excitation of the electric current in the column of metal pipes in the well using ground-based generator that is connected to one contact to ground the metal parts of the column and another contact is remote from the wellhead grounding electrode, the switching of the dielectric insert and receiving information from the borehole bottom, depending on the ripple caused by the switching of the dielectric insert, in contrast to the known method, as the ground of the generator using a constant current source, stable value, and obtaining information from the borehole bottom is carried out in dependence from the modulation voltage required to stabilize the DC ground of the generator (source of stabilized voltage) when the change in the effective value of the resistance of steel columns, caused by the switching of the dielectric insert.
Applying the device to implement the methods for the and, containing ground generator attached one clip to ground the metal parts of the column and the other clamp to the remote from the wellhead grounding-electrode dielectric insert that separates the metal column in the well on the upper and lower parts, the key to opening and closing of the contacts of the upper and lower parts of the metal columns, where as the ground of the generator used source of the stabilized DC, and between these clips installed the registration unit changes the voltage of this current.
The essence of the method. On the surface by using a constant current source, connected to one contact (clip) to ground the metal parts of the column and another contact (clip) - remote from the wellhead of the grounding electrode in the borehole serves DC, stable value, which, passing through the metal column, separated by a dielectric insert, generates an electromagnetic field which, propagating the breed in the well reaches the bottom zone and creates a potential difference between the metal casing and isolated part of it.
To send the message from downhole electromagnetic channel close or unlock (commute) key lower and upper metal columns, changing ffektivnoe, the conductivity between the grounding electrode of the constant current source and a metal column. With the closure of the key specified effective conductivity increases, and the voltage at the terminals of the constant current source falls and is registered by the registration unit, for example a differential voltmeter. The change in the measured voltage is judged on the parameters of the drilled formation. Duration and sequence of closures of the key is determined by the encryption module downhole unit of measurement (not shown due to being well-known). Thus, the useful signal is the change in the voltage at the terminals of the current source that maintains a constant (stable) current, which is determined by the conditions of transfer - conductive layer.
When this change (modulation) voltage ΔV on the ground clamps generator is calculated by the formula:
where G is the effective conductivity between the grounding electrode of the constant current source and the metal column is determined by the formula:
ΔG is the change in the effective value of the conductivity between the grounding electrode of the constant current source and a metal column,
α, dα - angles corresponding to the open and closed state of the dielectric is rate (see the drawing),
ρ is the resistivity of rocks, Ohm·m,
D1 is the distance between the metal pillar and the ground electrode, m,
D2 is the diameter of the grounding electrode, m,
With experimental coefficient, m
The value is defined in the "selection" voltage for the optimal value of the constant current, measured in metres and plays a supporting role, since ΔG is not calculated and the measured value. In formulas 1, 2, 3, above, takes into account the distance between the metal pillar to the grounding electrode, the diameter of the grounding electrode, the thickness of the dielectric insert, the length of the upper and lower parts of the metal columns, measured in meters. The consideration of these parameters improves the accuracy of the measurements.
The implementation of the method can be carried out by the device shown in the drawing.
The device includes a constant current source 1 is connected to one contact 2 to ground the metal parts of the column 3, and the other contact is remote from the wellhead to the distance D1 of the grounding electrode 4 with a diameter D2. Between these contacts (terminals) installed block registration of the change of voltage, for example a differential voltmeter 5. Metal column 3 in the well are separated by a dielectric insert 6 on the upper part with dline the L1 and the lower part with a length L2, the contacts 7 and 8, respectively, are closed/opened by a key 9. POS. 10 - top contact between the upper part of the metal columns 3 and earth, pos.11 - lower contact between the bottom of the metal columns 3 and ground. L3 is the thickness of the dielectric insert 6. α, dα - angles corresponding to open and closed contours dielectric insert 6.
Ground the generator 1 produces a constant regulated amount of current that is passing through the metal column 3, separated by a dielectric insert 6, generates an electromagnetic field which, propagating the breed in the well reaches the bottom zone and creates a potential difference between the metal casing 3 and an isolated part of the length L2.
With the closure of the key 9 effective conductance G increases and the voltage source constant current drops, which is registered by the differential voltmeter 5 connected to the terminals of the specified power source. However, changing the potential difference is modulated appropriately coded signal (information).
1. A method of transferring information from wells in the electromagnetic channel, including the excitation of the electric current in the column of metal pipes in the well using ground-based generator connected one behind the Imam to ground the metal parts of the column, and another clamp to the remote from the wellhead grounding electrode, the switching of the dielectric insert and receiving information from the borehole bottom, depending on the ripple caused by the switching of the dielectric insert, characterized in that as the ground of the generator using a constant current source, stable value, and obtaining information from the borehole bottom is carried out in dependence on the modulation voltage required to stabilize the DC ground of the generator, a source of constant current when the change in the effective value of the resistance of steel columns, caused by the switching of the dielectric insert.
2. Device for transferring information from wells in the electromagnetic channel containing ground generator attached one clip to ground the metal parts of the column and the other clamp to the remote from the wellhead grounding-electrode dielectric insert that separates the metal column in the well on the upper and lower parts, the key to opening and closing of the contacts of the upper and lower parts of the metal columns, characterized in that as the ground of the generator used source of the stabilized DC, and between these clamps installed unit registers the voltage of this current.
FIELD: oil and gas industry.
SUBSTANCE: device to be used in a well contains metal element with longitudinal axis, antenna with at least two separated groups of grooves made in metal element including at least two rows of grooves each and at least one electrical conductor. In each row of grooves there are at least two grooves. Each groove is made by its cutting in metal element surface. Rows in specified at least two groups of grooves are located in essence on opposite sides of metal element. Conductor is laid along each row of grooves and through each groove in grooves row. Section of electrical conductor passing along each row of grooves is unorthogonal to longitudinal axis of metal element.
EFFECT: increasing strength and rigidity of pipe.
20 cl, 8 dwg
SUBSTANCE: logging device has at least one antenna, having a vertical axis, and at least two electrodes spaced apart in the azimuthal direction. The antenna is placed between the two electrodes. The device also has a processor which is capable of powering one of the components, including at least one antenna and at least two electrodes, for generating electric current in the rock, and using a signal which is sensitive to electric current generated by the other of said components in order to determine resistivity of the rock.
EFFECT: measuring horizontal resistivity of rocks.
20 cl, 13 dwg
SUBSTANCE: claim describes resistivity measurements taken at multiple frequencies. An asymptotic high-frequency limit is determined and electrical efficiency is calculated in form of a ratio of the high-frequency limit of resistivity and low-frequency resistivity. Based on the electrical efficiency, petrophysical parameters of the rock, such as porosity and water saturation, can be calculated.
EFFECT: high accuracy of the obtained probing data.
23 cl, 11 dwg
SUBSTANCE: electromagnetic probe 1 measures electromagnetic properties of a geological formation GF in an bounded zone surrounding a well borehole WBH. The well-bore hole is filled with a well fluid DM. The probe comprises a pad 2 having a first face defining a first area meant to be in contact with the well borehole wall WBW. The probe 1 further comprises: at least two transmitting antennae 4A, 4B defining a central point CP between them, each antenna lying at a distance d0 from the central point, and at least a first 5A, 5B and a second set 5C, 5D of receiving antennae, each set comprising a first receiving antenna 5A, 5C and a second receiving antenna 5B, 5D. The first receiving antenna lies on one side of the transmitting antennae and the second receiving antenna lies on other side of the transmitting antennae so that each set encompass the transmitting antennae 4A, 4B. The probe 1 further comprises a coaxial cable with an open end 6A, placed on the first surface and lying perpendicular to the first area between the transmitting antenna 4A and the receiving antenna 5B.
EFFECT: high accuracy.
17 cl, 8 dwg
SUBSTANCE: device has an antenna, having an unbroken metallic element with a longitudinal axis and a radial axis and at least one cut made in the metallic element, as well as an electrical conductor passing through said at least one cut with formation of an antenna. High- magnetic permittivity material can be placed between the electrical conductor and the bottom of the cuts. The antenna can be made for operation as a radiator for emitting electromagnetic signals into a formation or as a receiver for receiving electromagnetic signals from a formation.
EFFECT: high mechanical strength.
22 cl, 8 dwg
FIELD: oil and gas production.
SUBSTANCE: well is equipped with casing string communicated with geological formation. The essence of the invention is like follows: first converter (14) is set in the first location. The first converter consists of two electrodes corresponding to first (141) and second (142) lower electrodes. The first and the second lower electrodes are in electrical contact with the casing string. Second converter (15) is set in the said second location. The second converter consists of two electrodes corresponding to first (151) and second (152) higher electrodes. The first or the second converters emit an electric signal applying it between corresponding electrodes. The second or the first converter receive the electric signal recording it with corresponding electrodes.
EFFECT: independence from geometric characteristics of well and fluid impedance, production string, casing string and formation.
21 cl, 13 dwg
FIELD: physics; geophysics.
SUBSTANCE: invention relates to geophysical survey in slim hole wells and geonavigation during drilling. The device has a metal pipe on which there are at least two receiving and two transmitting antenna units. Each antenna unit has cavities on the outer surface of the metal pipe for placing a collet consisting of two identical parts. On each part of the collet there are narrow through longitudinal slots. On the inner surface of each part of the collet there is a triangular ring shaped cavity. At the centre of the cavity on the inner surface of the metal pipe there is triangular ring-shaped cavity. In the cavity on the outer surface of the metal pipe there are narrow longitudinal slots in which there are ferrite inserts. At the centre of the antenna channel formed by triangular ring shaped cavities, there is an antenna wire which is insulated from the metal pipe and centred in the antenna channel by a ceramic layer deposited on the surface using a plasma technique. The antenna wire is connected through sealed leads to a resonance capacitor lying inside the metal pipe.
EFFECT: interchangeability of antenna units, increased reliability and mechanical strength.
FIELD: physics; geophysics.
SUBSTANCE: invention relates to well exploration geophysics, particularly for examining crosshole space during exploration of mineral deposits, including kimberlite pipes at small depth of exploration wells in the host rocks. Electric dipoles and magnetic sensors in form of magnetometres based on Josephson effect are placed in each of the two adjacent wells. A series of identical pulses of electric field with given duration and pulse ratio are emitted from the wells successively. The magnetometres based on Josephson effect are used to pick up orthogonal components of the magnetic component of the direct pulse perpendicular the well and of pulses reflected from irregularities in the medium under examination, as well as transit time of the direct pulse to the receiving device in the observation well, the transit time of reflected pulses from the emitter to the reflecting boundary and back, their amplitude, shape and phase.
EFFECT: larger examined space, reliable determination of existence, location and approximate dimensions of the ore body in the mesh of exploration wells and possibility of detecting ore bodies which insignificantly differ from the host rocks on electromagnetic properties.
FIELD: physics; geophysics.
SUBSTANCE: invention relates to geoelectrical exploration. The device for determining subsurface properties has a long housing with a longitudinal axis and is designed for placing in the well. On the housing there is a transmitter which is designed for transmitting electromagnetic energy, and a receiver placed on the housing at a distance less than two inches (5 cm) from the transmitter and is meant for receiving electromagnetic energy. The transmitter or the receiver has at last one antenna, the axis of which is inclined towards the longitudinal axis of the housing. The transmitter and the receiver are placed in insulating material inside the long housing. The transmitter can operate at frequency ranging from 1 MHz to 500 MHz. The sensor can include a triaxial antenna system or an antenna system with cross-dipoles.
EFFECT: possibility of measuring resistivity of rocks with high resolution in wells, drilled using drill fluids of any type, including chemically based drill fluid; independence from deviation of the instrument.
22 cl, 19 dwg
SUBSTANCE: disclosed invention refers to drilling equipment and is designed to control position of borehole of horizontal well between roof and bottom boundary of formation-collector. The facility consists of sensors of gamma-logging (GL) arranged in direct vicinity from a cone bit and orientated at the angle of 180° to each other, of a ferro-probe (FP) installed at the angle of 90° to diametre axis of GL sensors, the said sensors of GL and FP of the facility are arranged in a separate measuring above-cone bit module with a wireless electromagnetic channel of communication and are equipped with an electronic circuit of correlation of FP signals with pulses of GL sensors; the circuit contains a control unit, a switch of pulses of GL sensors, metres of GL pulses, and also a summarising metre of GL pulses; notably, an outlet of a measuring coil of FP is connected to an inlet of the control unit determining polarity of an output signal of FP and connected with the switch; depending on polarity of the outlet signal of FP the switch facilitates switching of channels of GL metres pulses flowing into corresponding metres of GL pulses designated as GL-'top" or GL-"bottom"; their outputs are connected to the summarising metre of GL pulses -"sum", in its turn connected with the measuring circuit of the above-cone bit module.
EFFECT: simplification of design and increased efficiency of control over process of working at horizontal drilling of wells, specifically in thin beds.
FIELD: measurement equipment.
SUBSTANCE: formation method of measurement data packages of a cable-free telemetric system during the well drilling involves coding of every four bits of information with a noise-like signal (NLS) with the length of 16 bits and information transfer by means of a phase-shift signal, packages of various types. The data measured in dynamics in the turbine drilling mode is transferred in S-O1-Z-O2-A-O3-"Г"-O4 packages consisting of synchronisation sending (S), diverter (O1), zenith (Z), diverter (O2), azimuth (A), diverter (O3), gamma background level ("Г"), diverter (O4). The data measured in dynamics in the rotary drilling mode is transferred in S-1-"Г"1-R1-"Г"2-R2-"Г"3 packages consisting of synchronisation sending (S), special NLS equal to one and serving for identification of the package type, gamma background level ("Г"1), formation resistance (R1), gamma background level ("Г"2), formation resistance (R2), and gamma background level ("Г"3). The data measured in statics is transferred with S-9-"Г"1-Z-R-A-"Г"2 packages consisting of synchronisation sending (S), special NLS equal to 9 and serving for identification of the packages type, gamma background level ("Г"1), zenith (Z), formation resistance (R), azimuth (A), and gamma background level ("Г"2).
EFFECT: increasing informativity of transferred parameters owing to increasing transfer frequency of logging parameters of gamma background and formation resistance.
FIELD: oil and gas industry.
SUBSTANCE: method for determining the saturation of reservoir beds involves determination of porosity coefficient of the investigated formation using two-probe neutron-neutron logging as per thermal neutrons. Calculation of porosity function as the ratio of intensities of flows of thermal neutrons. Recording of GIRZ spectrum intensities. Measurements are carried out during cement setting period of time after 2-4 days from the beginning of cementing of the well shaft, or 2-4 hours after the drilling tool has been raised out of the well. There are cross-plots as per dependences. On cross-plots there performed is approximation of lower points of quadratic function, which correspond to water-bearing formations with drill mud filtrate, and the function reflecting "deficiency of density and hydrogen content" in the nearest zone is calculated as per the given formula.
EFFECT: enlarging the range of application; improving its accuracy and informativity.
4 dwg, 2 cl
FIELD: oil and gas industry.
SUBSTANCE: method involves lowering of packers and equipment for extraction (pumping) of product in interval of product extraction on tubing string located against each productive formation. Down-hole measurements are performed by sensors. Obtained date is transmitted to ground receiving-processing unit by means of electronic self-powered measurement modules transmitting data signals by tubing string by electromagnetic pulses to common electronic self-powered transmitting module. Module is installed in tubing string assembly above the highest productive formation. Data high-frequency signals are amplified and transmitted to ground receiving-processing unit through rock. Equipment for extraction (pumping) of product is controlled by communication channel or by hydraulic communication channel using independent electronic modules. Modules contain housing in which the following is installed: valve for control of supply (removal) of fluid medium controlled by step-type tiny engine with driving mechanism of valve gate rotation, autonomous power supply unit, receiver of fluid pulses and dipole receiver of electromagnetic oscillations, amplifier modules of decoding device and power amplifier.
EFFECT: improving efficiency of monitoring of simultaneous separate operation of wells by means of provision of reliability of data transmission by two-way wireless communication between well equipment and ground receiving-processing unit.
8 cl, 6 dwg
FIELD: oil and gas industry.
SUBSTANCE: method of hydrodynamic investigations involves lowering of equipment for investigation of formation with self-contained measuring device by assembly pipes. Interval of investigation is sealed by packer. Arrangement of fluid influx sequence is provided by feed valve, investigated parameters are recorded by self-contained measuring device at the same time. Packers are released, equipment is lifted to wellhead by assembly pipes with further decoding of self-contained measuring device records. Tubing string is preliminary equipped with a seat, in which detachable receive/transmit module is lowered by geophysical cable. Parameters measured by self-contained measuring device are recorded by electromagnetic communication channel in predetermined time mode. Equipment corresponding to the method is also proposed.
EFFECT: improving efficiency of works on formation investigation by formation tester on pipes, improving informativity and speed of decoding or recorded parameters.
2 cl, 1 dwg
SUBSTANCE: downhole system comprises a three-phase power cable, a source of supply, an electric submersible pump and a gauge. The cable stretches from the surface into a well and may provide supply to the three-phase motor with certain voltage and frequency. The source of supply is connected to the three-phase power cable and may produce AC for supplying to gauges, sending it along all three conductors of the three-phase power cable. The pump is connected to the three-phase power cable and comprises a three-phase motor receiving supply along the specified three-phase power cable. The gauge is connected to the three-phase power cable using a capacitance link with the possibility to receive AC of gauge supply. At the same time the value of the current voltage is lower than the value of the three-phase motor supply voltage, and frequency is higher than frequency of the three-phase motor supply voltage.
EFFECT: improved system of downhole gauge supply.
18 cl, 3 dwg
FIELD: oil and gas industry.
SUBSTANCE: logging device includes housing, centring assembly and scanning head. Housing is oriented along longitudinal axis. Centring assembly positions the housing in the well centre and includes the first slide and group of centring brackets connected to it. The first slide has the possibility of sliding along longitudinal axis so that random control of radial retraction of the above group of centring brackets can be provided. Scanning head rotates scanning sensors axially inside the well around longitudinal axis and includes the second slide and connecting brackets connecting the second slide to the specified scanning sensors. Besides, the second slide has the possibility of sliding along longitudinal axis so that random control of radial retraction of the above sensors can be provided.
EFFECT: increasing the logging efficiency.
20 cl, 3 dwg
FIELD: oil and gas industry.
SUBSTANCE: method applied for signal transfer to measuring instrument in well shaft involves acceleration along measuring instrument axis in the specified acceleration profile. Pre-determined acceleration profile corresponds to the signal subject to transfer. Axial acceleration of measuring instrument is recorded, and signal from recorded axial acceleration is decoded. Signal recording system for measuring instrument in the well shaft includes accelerometer oriented along longitudinal axis of measuring instrument, and device for comparison of measurements made by means of accelerometer at least for one pre-determined acceleration profile.
EFFECT: easier signal transfer and simpler design.
15 cl, 4 dwg
FIELD: information technology.
SUBSTANCE: system for monitoring temperature of extended objects has temperature sensors, a means of collecting data coming from the extended object, a means of transmitting data, a computer for assessing and collecting data, lying away from the extended object and meant for receiving and assessing data. According to the invention, the system for monitoring temperature of extended objects further includes an Ethernet and the Internet, a network hub, temperature sensors, each lying in a separate protective housing and fitted with an integrated interface, connected to each other by a flexible cable and forming m thermistor chains with nm temperature sensors in each.
EFFECT: high accuracy of measurement and reliability, simple system for monitoring temperature of extended objects, wider field of use.
FIELD: oil and gas industry.
SUBSTANCE: method of simplification the collective work between the users at drill site and users at remote location consists of the following stages: many types of oil well data are collected at drill site for aggregated data formation; aggregated data is converted into standard format; aggregated data is saved on data aggregation server at drill site in standard format. Note that data aggregation server has data storage that has a set of analytical tools configured for aggregated data analysis. Oil well data is compared to the data description referred to it, compared data is saved in knowledge base at the drill site. Note that the compared data is used for conversion of unknown data of oil well into the standard format. The copy of aggregated data and compared data is saved on local server in remote location. Note that the local server stores the mirror copy of the data that is stored at data aggregation server. Note that the user at drill site can access the aggregated data and analyse them with the aid of a set of analytical tools at data aggregation server. The user in remote location can access the aggregated data saved at local server as well as analyse them with the aid of a set of analytical tools.
EFFECT: increase of efficiency of working processes control between the users at drill site and users in remote location.
25 cl, 16 dwg
FIELD: oil and gas industry.
SUBSTANCE: sensors are placed into a bed surrounding a well bore. A device is placed to realise the method into a well bore. The well bore zone is isolated. The pressure is changed in the zone with the help of making changes into the flow via a valve. Bed pressure is measured at a location of each sensor, and the received data is sent to an antenna array. Pressure is measured in the zone by a pressure gauge. Horizontal and vertical permeability of the bed is identified using the received measurements. At the same time the device comprises a bed tester (BD) lowered on a drilling string. The BD is equipped with a packer to isolate the well bore zone. The BD comprises a valve to control the fluid flow via a drilling string of a tool into the zone and from the zone and a pressure gauge to measure the pressure in the zone. The device additionally comprises an array of at least two antennas. Antennas are assembled on the tool above the packer so that in process of usage each antenna of the array is balanced with the appropriate pressure sensor placed into a bed, to obtain pressure measurement and to determine horizontal and vertical permeability.
EFFECT: possibility to characterise permeability of a bed in two dimensions, horizontally and vertically.
14 cl, 6 dwg
FIELD: well drilling technologies.
SUBSTANCE: method includes cutting a special conic thread, which is made with triangular profile with rounded corners, at sleeve and nipple portions of electric separator, sand-stream treatment is performed and also grease is removed from parts screwed together. After that a sub-layer is applied to increase adhesive metal properties. Composition dielectric material is applied to threaded connection of nipple portion, after that thread shape is altered by this material, then adhesive is applied to screwed surfaces of threads and sleeve and nipple portions of electric separator are screwed together. After that a layer of dielectric substance is applied along outer surface of subs. Inside the electric separator a dielectric insert is mounted or dielectric film is applied by pressing method with use of press-form. Dielectric film is applied on outer surface of electric separator by forming method under pressure with use of press-form or of composition dielectric material by winding method.
EFFECT: higher durability and reliability.
1 dwg, 1 ex