METHOD AND DEVICE FOR RESTORING HORIZONTAL WELL PRODUCTIVITY AND STIMULATING A FORMATION

Abstract

The group of inventions relates to the oil and gas production industry, and more particularly to cleaning the near-wellbore region of a horizontal well and also existing filters, as well as to stimulating oil production. The present method includes lowering a complex device consisting of an electrohydraulic emitter with a plasma discharger, a geophysical unit, and an acoustic emitter into a horizontal wellbore as far as the end of the horizontal section, using the geophysical unit to calibrate the instruments and measure the parameters of the wellbore prior to treatment, carrying out acoustic cleaning of the pores of the formation and the filters in the horizontal wellbore region, carrying out plasma treatment of the cleaned region to activate stagnant zones of the formation, measuring the current parameters using the geophysical unit, and repeating these processes throughout the entire horizontal section of the wellbore. The present device comprises a surface-based multifunctional monitoring and control panel, and the following downhole elements connected by a cable: a radial-type acoustic emitter, a geophysical instrument unit, and an electrohydraulic emitter with a plasma discharger, which are connected to one another by geophysical subs. The invention makes it possible to improve cleaning of the near-wellbore region of a formation and also to restore well production.

Description

TECHNICAL FIELD OF THE INVENTION

The group of inventions relates to the oil and gas production industry, in particular, to the bottom-hole zone cleaning of a horizontal well and mounted filters as well as to oil production stimulation. The method includes the delivery and placement of an ultrasonic transducer in the horizontal section of a well, operation of which in different modes and at various frequencies allows to improve well performance.

BACKGROUND OF THE INVENTION

In recent years the number of wells drilled with the horizontal section has risen in oil and gas production industry. Their drilling, development and operation significantly differ from the technology of hydrocarbon production via vertical wells, thus, methods used for stimulation in vertical wells in most of the cases are not suitable for horizontal wells.

There are known many methods for chemical treatment of a horizontal well (Patents RU 2531985 of 17 Sep. 2013, RU 2599155 of 24 Sep. 2015, RU 2520989 of 13 Mar. 2013, RU 2288356 of 22 Nov. 2005, RU 2471978 of 11 Jul. 2011, RU 2287680 of 10 Aug. 2004, RU 2554962 of 8 May 2014, RU 2235865 of 29 Sep. 2003, RU 2599156 of 24 Sep. 2015, 2144616 of 22 Jun. 1998, RU 2325517 of 29 May 2007). All these methods can be used only with a large amount of chemicals or involving the use of a large number of additional equipment. All this leads to high financial and labor costs, increased time and resource consumption. The ecological risk of these methods is also important.

From the prior art there are also known the methods for thermo-chemical effect on horizontal wells (Patents RU 2527434 of 27 Aug. 2014, RU 2004124482 of 27 Jan. 2006, RU 2287680 of 10 Aug. 2004). These methods have the same disadvantages as the abovementioned methods.

There are known the hydrodynamic methods for horizontal well treatment (RU 94033081 of 9 Sep. 1994, RU 2074305 of 9 Sep. 1994). These methods also are characterized by a large volume of equipment and high labor costs and time consumption.

The closest one in terms of technical essence and the result achieved is the method and device (Patent RU 2600249 of 24 Jan. 2014).

This method implies stimulation of oil reservoir and bottom-hole zone of a horizontal well by means of running a device for pulse generation in the well with the possibility of explosive plasma formation. It applies a two-module electrohydraulic device. In the first module there is a charging unit for capacitors and the second one is a capacitor unit, a transducer and an active material supply unit, connected to the control module and equipment at the wellhead with the ability to transfer charge and discharge data of the storage capacitors in order to initiate a coherent elastic vibrations at specified points of the horizontal end.

The device generates periodic directional short pulses due to the explosion of a calibrated wire, which leads to the formation of plasma and a high-pressure radial shock wave.

The descent of the device is made on a flexible tube of the coiled tubing type.

These method and device have a number of disadvantages. The main one is the impossibility of the shock wave distribution uniformly in the radial direction. The wave follows the path of least resistance, i.e. the energy goes through the most permeable pore channels. In the presence of a filter in a horizontal well, there is also an uneven distribution of energy along the radius of the well. The development of previously missed weakly drained stagnant zones is also of random character.

SUMMARY OF THE INVENTION

From the theory of oil field development, it is known that well productivity is influenced by many factors. Some of them have a mechanical origin, such as: formation of clay crust on the walls of the well during its drilling; penetration of drilling mud into the reservoir; penetration of cementing compounds filtration into the reservoir; perforation tunnels clogging by mechanical impurities in the filling fluid at the completion of the well or its repair; penetration of filling fluid into the reservoir; clogging of the formation pores by clays containing in the reservoir; perforation clogging by the deposition of asphalt-resin-paraffin sediments in the reservoir and the bottom-hole zone; salt deposits in the reservoir and the bottom-hole zone; formation and injection of various emulsions in the reservoir; injection of different solvents with solids; clogging of the reservoir pores and the bottom zone by the reaction products from different types of well treatment and reservoir treatment (chemical, thermal, etc.)

These factors significantly reduce reservoir permeability and, as a result, reduce well productivity, sometimes until the inflow stops completely.

The task of the proposed technical solution is to clean the bottom-hole formation zone from these types of pollution, to create cracks and microcracks in the radial direction with the length of dozens of meters, as well as to develop stagnant oil zones. This will not only restore the production rate of the well, but also significantly increase it comparing to the initial rate.

The technical result of the claimed group of inventions is to improve the cleaning of the bottom-hole formation zone, as well as to restore the flow rate.

The technical result of the claimed group of inventions is achieved by means of the method for restoring the productivity of horizontal wells and reservoir stimulation, in which a complex device comprised of an electrohydraulic transducer with a plasma discharger, a geophysical unit and an acoustic transducer, is run in the horizontal wellbore up to the end of horizontal interval, the device is bound by means of a geophysical unit and well parameters are measured before processing, the acoustic transducer cleaning the formation pores and filters of the horizontal well section, the plasma treatment of the cleaned area is carried out to involve stagnant zones of the reservoir, current well parameters are measured by the geophysical unit, the processes are repeated until the horizontal section of a well is completely passed.

In a specific case of implementation of the claimed technical solution the acoustic cleaning of formation pores and filters of a horizontal well is carried out by means of periodic effect caused by an elastic oscillations field of the ultrasonic frequency range in continuous mode and by means of pulse low-frequency acoustic effect, wherein the continuous effect is carried out by high-frequency oscillation of ultrasonic range at 2000 Hz, but in pulse mode the treatment is carried out with a frequency of 100 Hz.

In a specific case of implementation of the claimed technical solution the plasma treatment is carried out by means of high-pressure shock wave with an energy up to 3 kJ.

In a specific case of implementation of the claimed technical solution it can be used in horizontal wells for shale oil extraction.

In a specific case of implementation of the claimed technical solution it can be used in sidetrack wells.

The technical result of the claimed group of inventions is achieved by means of a complex device for restoring the productivity of a horizontal well and reservoir stimulation comprising: a ground-based multifunctional control board, a downhole acoustic transducer of a radial type, a geophysical unit, an electrohydraulic transducer with a plasma discharger connected via coil-tubing and connected to each other by means of geophysical adapters.

In a specific case of implementation of the claimed technical solution the ground-based multifunctional control board comprising: a power and control unit for the acoustic transducer, a log recorder, a power and control unit for the electrohydraulic device.

In a specific case of implementation of the claimed technical solution the acoustic transducer comprises: an electronics unit, an upper head providing the connection with a contact device for a cable lug, a lower head, a race-way for electric wires and metal airproof housings interconnected into one structure, in which piezoelectric transducers are mounted, and the outer and inner surface of each housing have trough-like deepenings, wherein in the housings there are bushings with screw-nuts placed on them and made to provide the possibility of connection and fixation of two adjacent housings one to another by means of metal wires attached simultaneously to the two screw-nuts of the adjacent housings, in addition, the housings are also connected to each other with the help of parts formed by pouring a rubber-plastic composition in the butting positions with the gap of the two adjacent housings.

In a specific case of implementation of the claimed technical solution it comprises an electrohydraulic plasma transducer of modular design, which allows to regulate the energy emission from 0.5 to 3 kJ using capacitors which make it possible to reduce the size of the transducer, a mechanical metal wire feeding unit involving easy replacement in field conditions.

In a specific case of implementation of the claimed technical solution the geophysical unit comprises a gamma-ray logging and a magnetic coupler locator, temperature and pressure sensors, a moisture meter and a flow meter.

In a specific case of implementation of the claimed technical solution the downhole electrohydraulic device is made of a modular design and comprises a stabilization unit, a capacitor unit and a plasma discharger, wherein the stabilization unit comprises a step-up and decoupling transformer, which also supplies a plasma ignition unit in the discharge interval.

In a specific case of implementation of the claimed technical solution capacitors in the capacitor unit are connected in parallel.

In a specific case of implementation of the claimed technical solution the power of the downhole electrohydraulic device is regulated in the range from 0.5 to 3 kJ by means of additional capacitor units.

In a specific case of implementation of the claimed technical solution the plasma discharger comprises a housing with an internal cavity, wherein the upper part is connected to a coupling bushing, and the lower part is connected to a bearing sleeve, the housing cavity contains a cylinder mounted on the middle part of the bearing sleeve, and the cylinder has a piston with a rod and a spring, a wire feeding machine is made in the form of a lever with a support platform and a wing with a spring is mounted on the upper part of the piston, on the support platform and on the wing on the side facing the wire there are directional notches, four rods are attached to the cylinder, that are the basis for a coil mount fitting, in the bearing sleeve there are holes for fixing positive and negative electrodes, and the electrodes are insulated with open areas providing a plasma discharge, in the negative electrode there is an axial hole for the wire, at the bottom of the bearing sleeve there is a guide cone mounted by means of racks.

BRIEF DESCRIPTION OF THE DRAWINGS

Details, features and advantages of the present invention are apparent from the following description of implementation of the claimed technical solution and the drawings showing:

FIG. 1—horizontal well with a complex device;

FIG. 2—is a longitudinal section of the downhole acoustic transducer;

FIG. 3—transducer with plasma discharger;

FIG. 4—downhole electrohydraulic device.

In the figures the parts are marked by numerals as follows:

1—coupling bushing, 2—housing, 3—coil, 4—attaching unit of the coil, 5—support, 6—wire; 7 cylinder; 8—piston; 9—bearing sleeve; 10—; 11—; 12—wire; 13—wing with a spring; 14—support platform; 15—; 16—; 17—electrodes; 18—piston holes; 19—negative electrode; 20—positive electrode; 21—screw; 22—terminal; 23—insulation; 24—electrohydraulic transducer with plasma discharger; 25—geophysical unit; 26—downhole acoustic transducer; 27—coil-tubing feeder; 28—coil-tubing; 29—special hoist. 30—housing; 31—piezoelectric transducer; 32 tightening screw; 33—rubber-metal gasket; 34—gasket; 35—bushing; 36—detail formed by pouring rubber-plastic composition; 37—metal wire; 38—screw-nut; 39—electric wires; 40—connecting assembly; 41—screw; 42—screw-nut; 43—plug.

DETAILED DESCRIPTION OF THE INVENTION

These results are achieved by application of the method for stimulation, which involves the delivery of a complex impact device to the end of a horizontal section of a well. The complex device comprises an acoustic transducer of radial type, a geophysical unit and an electrohydraulic transducer with a plasma discharger, which are interconnected by standard geophysical adapters.

The downhole acoustic transducer of radial type is designed so that it is possible to make it up to 50 meters long.

The design of the downhole acoustic device is explained by an illustration (FIG. 2), which displays the longitudinal section of the device.

The downhole acoustic transducer comprises an upper head providing connection to the contact device for the cable lug, a lower head, connected to each other in a single structure metal sealed housings (30), in which pairs of piezoelectric transducers (31) are placed with an offset relative to each other by an angle of 90°. Piezoelectric transducers (31) are composed of a longitudinally polarized, electrically connected piezoelectric washers (5 PCs. for each piezoelectric transducer). Piezoelectric transducers (31) are fastened together with clamping screws (32) (4 PCs.). Rubber-metal gaskets (33) are installed between the piezoelectric transducers. To ensure the fixation of piezoelectric transducers (31), sleeves (35) are installed in the housing (30), to which tightening screws (32) are attached.

This device provides independent operation of each piezoelectric transducer (31) located in housing (30). This is possible due to the mutual location of piezoelectric transducers (31), as well as to the presence of rubber-metal gaskets (33). This design allows to increase the selectivity of the acoustic effect on the well, bottom-hole zone and reservoir.

Upper and lower housings (30) are connected by metal cables (37) (4 PCs.) and detail (36) formed by rubber-plastic filling of the junction of two housings (30) with a small gap. This design provides flexibility that allows to pass the curved well sections easily. In addition, the connection of housings (30) by means of metal cables and detail (36) provides an increase in the transverse compliance of housings (30), which increases the efficiency of radiation in the radial direction. Such a device also has a longer service durability, since the presence of a flexible connection of housings (30) protects from its destruction under the influence of high well pressure and makes the device less fragile. Housing (30) is secured and sealed by compression and expansion in the radial direction of rubber gasket (34) with compression nuts (38) which are attached to bushings (35) (screwed or welded). Screw-nuts (38) have protruding parts that provide attachment of metal wires (37) to them. One of them is done in loop (closed connection), which is also thrown over the projecting parts of screw-nuts (38) located in two adjacent housings.

Piezoceramic washers are fastened immediately adjacent to each other by means of metal washers, screws (41) and screw-nuts (42). Prestressing of piezoceramic washers is carried out by means of screw (41) and screw-nut (42). By means of a preset voltage, it is possible to adjust a resonance frequency and an impedance value of each piezoelectric transducer (31) to the required values at the time of assembly. Additional sealing and fastening of housings (30) are provided by rubber-plastic filling (36) at the junction of two adjacent housings (30). The power supply to the piezoelectric transducers is provided by wires (39), which pass through the channel for electrical wires. Piezoelectric transducers (31) are connected to wires (39) in parallel. Wires (39) between two neighboring housings (30) are connected using standard geophysical connecting assemblies (“dimes”) (40) and poured rubber-plastic. To prevent rubber-plastic from getting into housing (30) in the cylindrical hole of bushing (35) there is plug (43). The outer and inner surface of housing (30) may have trough-like deepenings, made by milling along the length of the housing (30) (not shown in the figure). The presence of such depressions provides a certain direction of acoustic radiation, and also leads to transverse compliance of housing (30). This design allows to obtain radiation in the radial direction.

The electronics unit is hermetically connected to housing (30) (not shown in the figure), designed to generate a signal at an operating frequency of piezoelectric transducers (31) and to adjust the settings of piezoelectric transducers (31) automatically (frequency, voltage, phase shift) directly during operation, on the basis of the results processed in the electronics unit based upon the signals received from 5 built-in sensors for operation monitoring of piezoelectric transducers (31).

The transducer operates in two modes: continuous and pulse. In continuous mode, the transducer operates at the frequencies close to 20000 Hz. These frequencies provide the effects of the ultrasound:

• • rupture of intermolecular bonds (the destruction of stable relations on the border of the pores and the fluid);
  • capillary effect;
  • the destruction of plugging, asphaltene-resin-paraffin and mineral deposits;
  • oil rheology change, approximation of its properties to the properties of a Newtonian fluid.

Due to these effects, the pores of the bottom-hole formation zone within a radius of about 3 meters and perforation tunnels are cleaned.

In pulse mode, the transducer operates at frequencies of about 100 Hz. In this mode, the wavelength is several tens of meters, depending on the propagation medium (for example, in water it is 15 meters). Its peculiarity is a slight attenuation at long distances (more than 1000 meters). When the pulse operates high starting currents (up to 10 A) and there are emissions of powerful energy (about 20 kJ per hour), which allows an acoustic wave to spread over a distance of 1000 meters slightly losing its efficiency. This allows to influence the entire area of well supply and involve stagnant zones.

The design of the ultrasonic transducer is made in such a way that it allows additional electrical conductors to pass through. That makes it possible to connect a unit of geophysical instruments to it (also made with a through passage).

The geophysical unit comprises a gamma-ray logging device and a magnetic coupler locator, temperature and pressure sensors, a moisture meter and a flow meter.

The gamma-ray logging device and the magnetic coupler locator allows to bind the device to the depth of a well and the position of the device in a horizontal string for accurate processing.

Other devices allow real-time monitoring of the transducer and well operation. This allows to perform three tasks:

1. The transducer and well monitoring.

2. The possibility of adjusting the operation of the transducer depending on the received parameters.

3. Confirmation of the effectiveness of the proposed set of devices.

After the geophysical unit, there is connected an electrohydraulic transducer with a plasma discharger (FIG. 3). The transducer has the design features distinguishing it from the applied analogs.

Structurally, the electrohydraulic complex with a plasma discharger (EHCPD) comprises two main parts: a ground-based power supply and control unit and a downhole electrohydraulic transducer.

On the surface the complex device is connected through a coil-tubing to a multi-functional control board (MFCB). MFCB comprises: a power supply and control for acoustic transducer, a logging recorder, a power supply and control for electrohydraulic transducer.

All of them are connected by means of a coil-tubing (inside which the electric conductors pass) with devices delivered to the horizontal well section and perform the functions of power supply and control.

The downhole electrohydraulic transducer has a modular design (FIG. 4), consisting of a stabilization unit, a capacitor unit and a plasma discharger. Its length does not exceed 3 meters and its diameter does not exceed 44 mm, which ensures free passage of the device through all existing pump-and-compressor tubings.

The stabilization unit comprises a step-up-decoupling transformer, which also provides power supply to a plasma ignition unit in the discharge interval. In the capacitor unit the following capacitors are used: one lead is a coaxial pin and the other lead is a cylindrical housing, thus, capacitors are connected into a shunt bank by pins mounting. Such structure takes up minimal space and allows using small-sized components.

The modular design allows to increase the capacity of the downhole electrohydraulic device through the use of additional capacitor units in the proper range, e.g. from 0.5 to 3 kJ. Modular design is ensured using rubber-plastic connection strengthened with wires.

A special role in the present invention is played by the plasma discharger design. Unlike the prototype, it has a mechanical drive instead of the electric one. It is designed as a modular, easy to disassemble structure, which makes it easy to replace any parts, and install a new spool of wire, which is particularly important in field conditions. Discharger housing (2) is screwed onto coupling sleeve (1) and fixed with a screw. At the bottom of the discharger housing there is bearing sleeve (9) made of glass-fiber plastic, to which all the other elements are attached.

In the middle part of the sleeve there is cylinder (7) screwed in, in which there is piston (8) with a rod and a spring. In piston (8) there are small holes (18) for pressure equalizing of the head-end volume and the pressure in the oil well. On the upper part of piston (8) there is wire feeding mechanism (6), which is at the same time a stop to hold the piston in a predetermined position. The feeding mechanism is a lever with a support platform (14) and a wing with a spring (13). On the support platform and on the wing on the side facing wire (12), there are directional notches, allowing the feeding mechanism to move up without affecting the wire, and providing engagement with the wire when it moves down.

Four rods (5) are attached to cylinder (7), that are the basis for attachment point (4) of coil (3). The rods also ensure that the cylinder does not get knocked out of sleeve (9) by piston (8), due to being mounted on coupling sleeve (1).

Bearing sleeve (9) has two holes for mounting electrodes (17, 19). The electrodes have insulation (23) eliminating the possibility of backstreaming. Open areas are only those providing for plasma discharge. Power cable is connected to positive electrode (20) with terminal (22) and screw bolt (21). Power cable is also connected to negative electrode (19), but there is an axial hole in the electrode made for wire (12). Sealing insert (15) is used to seal the hole.

Guide cone (11) is attached to the bottom of the bearing sleeve with racks (10). It ensures free movement of the downhole electrohydraulic device in the pump-and-compressor tubing, and, at the same time, along with the racks, it protects the electrodes from mechanical impact.

The electrohydraulic complex operates as follows:

Ground-based power supply unit is connected to 220 V AC network, converts it to direct current and passes it through the geophysical cable to the stabilization unit and the capacitor unit. Electrical energy is accumulated in the capacitors and once they are full plasma discharge occurs through electrodes (17, 19), connected by wire (12), which is preset in a predetermined position.

Plasma discharge results in the electrohydraulic shock affecting the oil reservoir and the bottom-hole zone, which contributes to the stimulation of enhanced oil recovery and oil production intensification.

The shock wave also impacts piston (8), which goes up, compresses the spring and moves wire feeding mechanism (6). The surfaces of support platform (14) and wing (13) easily slide upwards on wire (12). When the spring is straightened the feeding mechanism is lowered and due to the special notches on the support platform, the wing and the wing springs, provides its pressing, pulls the wire down through the negative electrode until it contacts the positive electrode. Then the whole cycle is repeated.

Therefore:

Firstly, the transducer has the modular design which allows increasing the capacity of the downhole electrohydraulic device using different number of modules, in the proper range from 0.5 to 3 kJ (depending on the geological characteristics of the well and its design).

Secondly, there are special capacitors used in the transducer to minimize the occupied volume. As a result, the length of the transducer is 2 times less than analogues, and the diameter is reduced down to 52 millimeters.

Thirdly, unlike analogues, there is a mechanical wire feeding device is used, made in the form of a quick-release unit, which allows to change the wire in field conditions and avoid complex electrical and electronic circuits.

The complex device is delivered to the horizontal section of a well by means of a coil-tubing, which is wound on a special drum and is driven by a special unit for its unwinding and a special conveyer for its delivery to the well. The hoist with a coil-tubing are commercially available in many factories.

On the surface the complex device is connected to a multi-functional control board (MFCB) through a coil-tubing. MFCB consists of units: power supply and control of an acoustic transducer, logging recorder, power supply and control of an electrohydraulic transducer. All of them are connected through a coil-tubing (inside which the electric conductors pass) with devices delivered to the horizontal well section and perform the functions of power and control.

The method is implemented as follows: on a coil-tubing, with the help of a special hoist, a complex device consisting of an electrohydraulic transducer with a plasma discharger, a geophysical unit and an acoustic transducer are lowered into the horizontal wellbore. The complex device is pushed to the end of the horizontal section by means of the geophysical unit, the devices are bound, and the parameters of the well are measured prior to processing.

Within two hours (the time depends on the parameters of the well and calculated in laboratory conditions), the near and distant productive well zones are treated in continuous (operated for an hour at a constant frequency of 20 kHz) and pulse (operated 10 pulses per second at a frequency of 100 Hz for an hour) modes, which leads to the restoration of the permeability of the near productive well zone and to the movement of the reservoir fluid in the distant and stagnant zones.

Then the electrohydraulic transducer is activated and the plasma treatment of the cleaned area (up to 50 meters) is carried out. A shock wave of high-pressure energy up to 3 kJ (the amount of energy depends on the number of capacitors in the modules and is calculated mathematically) is evenly distributed in the radial direction, creating cracks in the near productive well zone and pushing oil out of stagnant zones. Then the geophysical unit is connected, and the current parameters are measured, allowing, if necessary, to adjust the settings of the equipment. Then the processes are repeated until the horizontal section of a well is completely passed.

For effective and safe movement of the complex in the horizontal section, it is equipped with centralizers and a pressure sensor.

REFERENCES

• 1. L. A. Yutkin. Electrohydraulic effect and its application in industry. Leningrad: Mechanical engineering, Leningrad Dep., 1986, 253 p.
• 2. O. L. Kuznetsov, E. M. Simkin, J. Chilingar. Physical basis of vibration and acoustic impact on the oil and gas reservoirs, 2001, 260 p.
• 3. O. L. Kuznetsov, I. A. Chirkin, Yu. A. Kuryanov et al. Seismoacoustics of porous and fractured geological media, 2007, 432 p.
• 4. Yu. V. Revizskiy, V. P. Dyblenko. Study and validation of the mechanism of oil recovery using physical methods. Moscow, Nedra publishing house, 2002, 300 p.
• 5. Patent No. RU 2248591, Borehole source of elastic vibrations, 2004.
• 6. Patent No. RU 2385472, Well source of seismic energy, unit of high voltage electrode and unit of low voltage electrode, 2007.
• 7. Patent No. RU 2373386, Method for action at well bottom zone and oil-saturated beds (versions) and device for its realisation, 2008.
• 8. Patent No. US 2012/0043075, Method and assembly for recovering oil using elastic vibration energy, 2012.
• 9. http://www.bluesparkenergy.net/wasp/#applications

Claims

1. A method for restoring productivity of a horizontal well and stimulating a reservoir, comprising:

lowering a complex device, comprising an electrohydraulic transducer with a plasma discharger, a geophysical unit and an acoustic transducer, into the horizontal well bore up to the end of a horizontal section of the horizontal well, wherein the complex device is bound by means of the geophysical unit and the well bore parameters are measured before the next step;

acoustically cleaning pores of the reservoir and filters of the horizontal section of the well;

treating the cleaned area with a plasma to draw stagnant zones of the reservoir into operation with a source;

measuring current parameters of the well by the geophysical unit;

repeating the abovementioned processes throughout the entire horizontal section of the well.

2. The method according to claim 1, characterized in that the acoustic cleaning of pores of the reservoir and filters of the horizontal well is carried out by periodic exposure to an elastic oscillation field of an ultrasonic frequency range in a continuous mode and by means of a pulse low-frequency acoustic effect, wherein in the continuous mode, the exposure is carried out by a high-frequency oscillation of the ultrasonic range of 2000 Hz, and in the pulse mode, the exposure is carried out with a frequency of 100 Hz.

3. The method according to claim 1, characterized in that the plasma treatment is produced by a high-pressure shock wave with an energy of up to 3 kJ.

4. The method according to claim 1, characterized in that it can be used in horizontal wells for shale oil extraction.

5. The method according to claim 1, characterized in that it can be used in sidetrack wells.

6. A complex device for restoring productivity of a horizontal well and stimulation of a reservoir, comprising: a ground-based multifunctional control board, a downhole acoustic transducer of a radial type, a geophysical unit, an electrohydraulic transducer with a plasma discharger connected via coil-tubing and connected to each other by means of geophysical adapters.

7. The device according to claim 6, characterized in that the ground-based multifunctional control board consists of the following units: a power and control unit for the acoustic transducer, a log recorder, a power supply unit and control unit for the electrohydraulic transducer.

8. The device according to claim 6, characterized in that the acoustic transducer comprises:

an electronics unit, an upper head providing connection with a contact device for a cable lug, a lower head, a conduit for electric wires and metal airproof housings interconnected into one structure, in which piezoelectric transducers are mounted, and the outer and inner surface of each housing have trough-like deepenings,

wherein in the housings there are bushings with screw-nuts placed on them and made to provide a possibility of connection and fixation of two adjacent housings one to another by means of metal wires attached simultaneously to two screw-nuts of the adjacent housings, in addition, the housings are also connected to each other with the help of parts formed by pouring a rubber-plastic composition in the butting positions with the gap of the two adjacent housings.

9. The device according to claim 6, characterized in that it comprises an electrohydraulic plasma transducer of a modular design, which allows to regulate the energy emission from 0.5 to 3 kJ using capacitors which make it possible to reduce the size of the transducer, and a mechanical metal wire feeding unit involving easy replacement in field conditions.

10. The device according to claim 6, characterized in that the geophysical unit comprises a gamma-ray logging and a magnetic coupler locator, temperature and pressure sensors, a moisture meter and a flow meter.

11. The device according to claim 6, characterized in that the downhole electrohydraulic device is made of a modular design and comprises a stabilization unit, a capacitor unit and a plasma discharger,

wherein the stabilization unit comprises a step-up and decoupling transformer, which also supplies a plasma ignition unit in the discharge interval.

12. The device according to claim 11, characterized in that the capacitors in the capacitor unit are connected in parallel.

13. The device according to claim 11, characterized in that the power of the downhole electrohydraulic device is regulated in the range from 0.5 to 3 kJ by means of additional capacitor units.

14. The device according to claim 11, characterized in that the plasma discharger comprises a housing with an internal cavity, wherein the upper part is connected to a coupling bushing, and the lower part is connected to a bearing sleeve, the housing cavity contains a cylinder mounted on the middle part of the bearing sleeve, and the cylinder has a piston with a rod and a spring, a wire feeding machine is made in the form of a lever with a support platform and a wing with a spring is mounted on the upper part of the piston, on the support platform and on the wing on the side facing the wire there are directional notches, four rods are attached to the cylinder, that are the basis for a coil mount fitting, in the bearing sleeve there are holes for fixing positive and negative electrodes, and the electrodes are insulated with open areas providing a plasma discharge, in the negative electrode there is an axial hole for the wire, at the bottom of the bearing sleeve there is a guide cone mounted by means of racks.