RU125249U1 - ELECTRIC HEATING DEVICE FOR HEAT TREATMENT OF FORWARDING ZONE PLAY - Google Patents

Abstract

The utility model relates to the field of oil and gas industry, and is mainly intended for the heat treatment of the bottomhole zone of a producing formation of a well with high-viscosity oil. The technical result consists in expanding the zone of coverage of the bottomhole formation zone by heating both along the height of the wellbore and depth, by making the heater lengthy and due to a simultaneous increase in power and heat transfer. Essence: the device is fixed in the well opposite the perforation zone of the reservoir 1 at the end of the tubing string 2. The device consists of at least two heater sections (three heater sections are shown in Fig. 3). Each section of the heater consists of a sealed metal housing 3, made in the form of a tubular cylinder, partially filled with an aqueous electrolyte solution 4. The upper part of the housing is equipped with an input unit 5 for conductive (power or heating) cable 6 to the inside of the housing connected to the last screw or flange connection 21 In the input unit 5 there is also a thread 7 for connecting the heater section to the tubing string 2 through the coupling 8. The temperature sensor 9 is fixed in the input unit 5. Three electrodes 10, 11 and 12 are placed in the housing 3 (figure 1 and figure 2). In Fig. 3, one electrode is placed in each section, and the device consists of three sections of the heater. Moreover, heat-resistant centralizers-insulators are installed along the length of the electrodes 13. To connect the current-carrying cores 14 of the conductive cable 6 to the three electrodes 10, 11, 12, an insulator 15 is installed under the input device 5 with a contact clip 16. At the bottom of the case 3 are electrodes 10, 11, 12 strung on the nozzle 17, made of a dielectric material, to avoid contact of the electrodes and the housing. The upper part of the housing 3 forms the steam zone 18 of the electric heater. To increase the contact area of the electrolyte 4 and electrodes 10, 11, 12, metal disks 19 with perforations can be placed in the device case (FIG. 2; section AA), alternately connected with electrodes 10, 11, 12, and in places of possible contact the disk 19 and the housing 3, the disk 19 and the non-connected electrodes are fitted with heat-resistant insulators 20, to prevent the electrodes from contacting each other and the housing. Conductive cable 6 can pass inside the housing 3 sections of the heater, or pass on its outer surface. In the latter case, it is fixed and protected by protectors. 1 bp f-ly; 8 hp f-ly; 3 il.

Description

The utility model relates to the field of oil and gas industry, and is mainly intended for the heat treatment of the bottomhole zone of a producing formation of a well with high-viscosity oil.

Known electric heating device for heat treatment of the wellbore zone, comprising a heater housing, a power supply cable, electrode discs mounted on a conductor (RF Patent No. 21699830).

The known device is simple and reliable. However, the disadvantage of this device is insufficient power and heat transfer due to the placement of heat-resistant insulators on the inner surface of the housing. In addition, among the shortcomings of this device, it is possible to single out the impossibility of warming up the wide bottomhole formation zones, due to the small length of the device and the impossibility of its increase.

The closest to the proposed utility model is a downhole electrode heater (Patent RF №2119577), containing an electrode made in the form of a tubular body, partially filled with electrolyte, and a second electrode installed coaxially in the body, the lower end of which has a working part in the electrolyte and is equipped with a nozzle.

The main disadvantage of this device is low power due to single-phase power, as well as insufficient heating area of the bottomhole formation zone, which is limited only by the length of the heater body.

The technical result achieved by the proposed utility model is to expand the coverage area of the bottomhole formation zone by heating both in the height of the wellbore and in depth by making the heater lengthy and due to a simultaneous increase in power and heat transfer.

This technical result is achieved by the proposed electric heating device for heat treatment of the well bottom zone, including a heater section consisting of a body made in the form of a sealed tubular cylinder, partially filled with an aqueous electrolyte solution, placed in the body of the internal electrode, made in the form of a metal rod, immersed working part of the specified electrolyte, from a conductive cable connecting the power source to the electrode, and from the input unit of the conductive cable in the housing connected to the latter, while the new one is that at least one electrode is placed inside the housing, which is equipped with a heat-resistant centralizer-insulator, and the device consists of at least two connected conductive cables providing supply to the electrodes of three-phase alternating current, heater sections, which are mounted in the well at the lower end of the tubing string of tubing successively one after the other or at a distance in length of one with ktsii tubing from each other, wherein the connecting section of the heater cable conductor extends within the heater body sections or on its outer surface.

In preferred embodiments of the proposed device:

- it consists of identical or differing structurally by the number of electrodes of the sections of the heater;

- sections of the heater are connected to each other through a socket or flange connection;

- the body of the heater section is provided with a centering element; - inside the conductor cable entry unit, at least one pressure and / or temperature control sensor is placed in the body of the heater section; power and readings from which occur through the conductive cable;

- as a conductive cable, it contains a power or heating cable;

- to increase the contact area of the electrolyte and electrodes, metal discs with perforations, alternately connected to electrodes, are placed in the body of the device; moreover, heat-resistant insulators are installed in the places of possible contact between the disc and the body, disc and not connected electrodes;

- it is placed in the well in the zone of the bottomhole formation zone;

- when placing a conductive cable on the outer surface of the housing, the specified cable is fixed and protected by protectors.

The technical result is ensured by the following.

Due to the fact that at least one electrode is placed inside the case, and this means that there may be several electrodes to which a three-phase alternating current is supplied by means of a conductive cable, the power of the electric heater is increased, and as a result, the the heating zone of the bottomhole formation zone in depth.

The supply of the electrode (s) with a heat-resistant centralizer-isolator protects the housing from contact with the electrode (s) and the contact of the electrodes with each other, which increases the reliability of the device and eliminates emergency situations caused by short-circuiting.

Due to the fact that the proposed device consists of at least two sections of the heater, it is possible to expand the coverage zone of the bottomhole formation zone by the height of the wellbore due to the length of the heater. Moreover, this goal is achieved by placing the heater sections directly one after the other, and by placing them at a distance of one tubing length from one another, depending on well conditions. The use of identical sections of the heater or different in design features (for example, by the number of electrodes, or by the presence or absence of metal perforated discs) allows for different heating power at different parts of the wellbore depending on the process conditions. This allows you to optimize the heating conditions and provide energy-efficient energy consumption.

The connection of the heater sections (the end of the casing and the input unit is threaded) is performed by means of a traditional coupling connection, which is used in assembling the tubing string, which makes it possible to simply and reliably install the installation of the proposed device into the column. The same applies to the unified flange connection.

The presence in the proposed device of the input unit of a conductive cable into the body of the heater section ensures reliable protection of the cable and the monitoring sensors from damage.

The placement of the conductive cable connecting the heater section inside the section housing or along its outer surface allows to take into account the downhole conditions of the device installation, for example, the diameter of the tubing string.

Moreover, in the preferred embodiment, when placing a conductive cable on the outer surface of the housing, it is proposed to fix the specified cable and protect it with protectors to prevent its damage. As protectors it is recommended to use traditional protectors, for example, described in patents of the Russian Federation No. 82468 and No. 82469.

Supply of the heater section housing with the centering element allows precise installation of the electric heating device inside the tubing, and also avoids contact of the housing with the walls of the tubing, which will prevent damage to the housing.

Placing a conductive cable inside the input unit into the heater section of the pressure and / or temperature control sensor allows you to monitor the operation of the device. And due to the fact that the power supply and removal of indicators from the specified sensor is produced through a conductive cable, it is easy to obtain information.

Moreover, the use of a power or heating cable as a conductive cable ensures the unification of the operation of the claimed device without reference to a specific type of cable.

Due to the fact that metal discs with perforations, alternately connected to electrodes, can be placed in the housing of the device, and heat-resistant insulators are installed in the places of possible contact between the disk and the housing, the disk and unconnected electrodes, the contact area of the electrolyte and electrodes is increased, which means it increases power of the heater that will provide thermal impact on a great depth of the bottomhole zone.

The inventive electric heating device for heat treatment of the well bore zone is illustrated by drawings, where figure 1 shows a longitudinal section of the heater section of the device; figure 2 is a longitudinal section of the heater section of the device with metal discs with perforations; Fig.3 is a longitudinal section of a device mounted in a tubing string.

The proposed electric heating device is fixed in the well opposite the perforation zone of the reservoir 1 at the end of the tubing string 2. The device consists of at least two heater sections (three heater sections are shown in Fig. 3). Each section of the heater consists of a sealed metal housing 3, made in the form of a tubular cylinder, partially filled with an aqueous electrolyte solution 4. The upper part of the housing is equipped with an input unit 5 for conductive (power or heating) cable 6 to the inside of the housing connected to the last threaded connection In the input unit 5 there is also a thread 7 for connecting the heater section to the tubing string 2 through the coupling 8. In the input unit 5 a temperature and / or pressure sensor 9 is fixed. the placement of several diverse sensors 9. In the housing 3 there are three electrodes 10, 11 and 12 (figure 1 and figure 2). In Fig. 3, one electrode is placed in each section, and the device consists of three sections of the heater. In this case, along the length of the electrodes, heat-resistant centralizers-insulators 13 are installed (not shown in FIG. 3). To connect the conductive wires 14 of the conductive cable 6 to the three electrodes 10, 11, 12, an insulator 15 is installed under the input device 5 with a contact clamp 16. In the lower part of the housing 3, the electrodes 10, 11, 12 are strung on a nozzle 17 made of a dielectric material exclude contact of the electrodes and the housing.

The upper part of the housing 3 forms the steam zone 18 of the electric heater. To increase the contact area of the electrolyte 4 and electrodes 10, 11, 12, metal disks 19 with perforations can be placed in the device case (Fig. 2; section A-A), alternately connected to electrodes 10, 11, 12, and in places of possible contact the disk 19 and the housing 3, the disk 19 and the non-connected electrodes are fitted with heat-resistant insulators 20, to prevent the electrodes from contacting each other and the housing.

Conductive cable 6 can pass inside the housing 3 sections of the heater, or pass on its outer surface. In the latter case, it is fixed and protected by protectors (not shown in the drawing).

The proposed electric heating device for the heat treatment of the well bottom zone works as follows.

The power cable 6 (or heating cable), the electrodes 10, 11, 12, placed in the body section of the heater, filled with a conductive liquid 4 (aqueous electrolyte solution), the voltage in the form of three-phase AC, then from the electrodes 10, 11 , 12 through the liquid 4 to the housing 3 will flow current, causing the electrolyte to heat, boil it and generate steam, which in turn will lead to heat exchange between the wall of the housing 3 and the downhole fluid, producing further heat treatment of the bottomhole zone.

During operation, the pressure inside the housing 3 of the heater increases, the electrolyte 4 turns into steam and its level decreases and the current of the device decreases, by reducing the contact area of the electrolyte 4 with electrodes 10, 11, 12, which indirectly determines the ratio of water-steam volumes and allows judge the parameters of the thermodynamic process. When cooling and condensation of steam electrolyte level 4 in the housing 3 is restored, the resistance of the heater takes the initial value.

Thus, the proposed device allows you to increase the heating power and heat transfer, respectively, due to the supply of three-phase alternating current and other placement of heat-resistant insulators that do not interfere with the heat transfer to the reservoir, resulting in an increased heating of the reservoir inland.

And due to the use in the inventive device of a system of series-connected heater sections, an increase in the extended heating zone along the wellbore is provided.

Claims (9)

1. Electric heating device for heat treatment of the well bottom-hole zone, including a heater section consisting of a body made in the form of a sealed tubular cylinder, partially filled with an aqueous electrolyte solution, from an internal electrode placed in a body, immersed in the working part into electrolyte, from a conductive cable connecting the power source to the electrode, and from the conductor cable input unit to the case connected to the latter, from Differing in the fact that inside the housing there is at least one electrode that is equipped with a heat-resistant centralizer-insulator, and the device consists of at least two connected electrically conductive cables providing three-phase alternating current to the electrodes, which are mounted in the well at the lower end of the tubing tubing string in series directly behind each other or over a distance of one tubing section from each other, the connecting section of the current heater A conductive cable runs inside the body of the heater section or along its outer surface. 2. The device according to claim 1, characterized in that it consists of identical or different structurally by the number of electrodes of the sections of the heater. 3. The device according to claim 1, characterized in that the sections of the heater are connected to each other by means of a coupling or flange connection. 4. The device according to claim 1, characterized in that the body section of the heater is provided with a centering element. 5. The device according to claim 1, characterized in that inside the unit for inserting a conductive cable into the body of the heater section is placed, at least, one sensor for controlling pressure and / or temperature, power supply and readings from which occurs through a conductive cable. 6. The device according to claim 1, characterized in that as a conductive cable, it contains a power or heating cable. 7. The device according to claim 1, characterized in that to increase the contact area of the electrolyte and electrodes, metal discs with perforations are placed in the body of the device, alternately connected to the electrodes, and heat-resistant are installed in places of possible contact between the disc and the body, disc and not connected electrodes insulators. 8. The device according to claim 1, characterized in that it is placed in the well in the zone of the bottomhole formation zone. 9. The device according to claim 1, characterized in that when placing a conductive cable on the outer surface of the housing the specified cable is fixed and protected by protectors.

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