Plasma sources, systems, and methods for stimulating wells, deposits and boreholes

Abstract

Some embodiments include a plasma source. The plasma source includes: (i) a plasma emitter having a first electrode and a second electrode defining an electrode gap therebetween; (ii) stands disposed adjacent to the electrode gap and the plasma emitter; (iii) emitter openings configured such that shockwaves generated by the plasma source are directed through the emitter openings and radially from the plasma emitter, wherein adjacent emitter openings of the emitter openings are separated from each other by at least one stand of the stands; (iv) an enclosure housing at a distal end of the plasma emitter and having a delivery device configured to introduce a conductor through an opening in the second electrode and into the electrode gap; and a device housing at a proximal end of the plasma emitter and having a transformer, a capacitor unit, and a contactor. Other embodiments of related systems and methods are also disclosed.

Claims

1. A plasma source comprising: a plasma emitter comprising a first electrode and a second electrode, the first electrode and the second electrode defining an electrode gap therebetween; multiple stands disposed adjacent to the electrode gap and adjacent to the plasma emitter; multiple emitter openings configured such that shockwaves generated by the plasma source are directed through the multiple emitter openings and radially from the plasma emitter, wherein adjacent emitter openings of the multiple emitter openings are separated from each other by at least one stand of the multiple stands; an enclosure housing at a distal end of the plasma emitter, the enclosure housing comprising a delivery device configured to introduce a conductor through an opening in the second electrode and into the electrode gap; and a device housing at a proximal end of the plasma emitter, the device housing comprising: a transformer; a capacitor unit electrically coupled to the transformer; and a contactor electrically coupled to the capacitor unit and the first electrode, wherein: the delivery device comprises an electromagnet and a platform comprising a dielectric material; the platform contacts the second electrode; and the electromagnet is coupled to the platform.

2. The plasma source of claim 1 wherein: the multiple emitter openings further are configured such that shockwaves generated by the plasma source are directed through the multiple emitter openings and radially from the plasma emitter with a sum angle of up to 330 degrees.

3. The plasma source of claim 1 wherein: each stand of the multiple stands comprises one of a rounded trapezoidal cross-section or a triangular cross-section.

4. The plasma source of claim 3 wherein: the one of the rounded trapezoidal cross-section or the triangular cross-section comprises an apex angle measuring between ten and sixty degrees.

5. The plasma source of claim 1 wherein: each emitter opening of the multiple emitter openings is equally sized with each other.

6. The plasma source of claim 1 wherein: the enclosure housing is attached to the plasma emitter by a threaded connection.

7. The plasma source of claim 1 wherein: the conductor comprises a homogenous electroconductive material.

8. The plasma source of claim 1 wherein: the conductor comprises a diameter of 0.3 to 0.9 millimeters.

9. The plasma source of claim 1 further comprising: the first electrode comprises a refractory metal or a refractory alloy.

10. The plasma source of claim 1 wherein: the plasma emitter comprises a pulse counter configured to count pulses of the shockwaves.

11. The plasma source of claim 1 wherein: the device housing comprises a flexible housing comprising multiple bellows that contain the high voltage transformer, the capacitor unit, and the contactor.

12. The plasma source of claim 1 wherein: the first electrode is electrically insulated from the plasma emitter; and the second electrode is electrically grounded to the plasma emitter.

13. The plasma source of claim 1 wherein: the enclosure housing is sealed and contains a dielectric compensation liquid.

14. A system comprising: a plasma source comprising: a plasma emitter comprising a first electrode and a second electrode, the first electrode and the second electrode defining an electrode gap therebetween; multiple stands disposed adjacent to the electrode gap and adjacent to the plasma emitter; multiple emitter openings configured such that shockwaves generated by the plasma source are directed through the multiple emitter openings and radially from the plasma emitter, wherein adjacent emitter openings of the multiple emitter openings are separated from each other by at least one stand of the multiple stands; an enclosure housing at a distal end of the plasma emitter, the enclosure housing comprising a delivery device configured to introduce a conductor through an opening in the second electrode and into the electrode gap; and a device housing at a proximal end of the plasma emitter, the device housing comprising: a transformer; a capacitor unit electrically coupled to the transformer; and a contactor electrically coupled to the capacitor unit and the first electrode; a support cable comprising a fixed end and a remote end coupled to the plasma source; and a ground control unit coupled to the fixed end of the support cable, wherein: the delivery device comprises an electromagnet and a platform comprising a dielectric material; the platform contacts the second electrode; and the electromagnet is coupled to the platform.

15. The system of claim 14 wherein: the multiple emitter openings further are configured such that shockwaves generated by the plasma source are directed through the multiple emitter openings and radially from the plasma emitter with a sum angle of up to 330 degrees; and each stand of the multiple stands comprises one of a rounded trapezoidal cross-section or a triangular cross-section.

16. The system of claim 15 wherein: the one of the rounded trapezoidal cross-section or the triangular cross-section comprises an apex angle measuring between ten and sixty degrees.

17. The system of claim 15 wherein: each emitter opening of the multiple emitter openings is equally sized with each other.

18. A method comprising: providing a plasma source, the plasma source comprising: a plasma emitter comprising a first electrode and a second electrode, the first electrode and the second electrode defining an electrode gap therebetween; multiple stands disposed adjacent to the electrode gap and adjacent to the plasma emitter; multiple emitter openings configured such that shockwaves generated by the plasma source are directed through the multiple emitter openings and radially from the plasma emitter, wherein adjacent emitter openings of the multiple emitter openings are separated from each other by at least one stand of the multiple stands; an enclosure housing at a distal end of the plasma emitter, the enclosure housing comprising a delivery device configured to introduce a conductor through an opening in the second electrode and into the electrode gap; and a device housing at a proximal end of the plasma emitter, the device housing comprising: a transformer; a capacitor unit electrically coupled to the transformer; and a contactor electrically coupled to the capacitor unit and the first electrode; positioning the plasma source in a fluid medium; delivering the conductor into the electrode gap; creating a metallic plasma in the electrode gap; generating a shockwave in the metallic plasma in the electrode gap; and transmitting the shockwave from the metallic plasma into the fluid medium to create oscillations in the fluid medium, wherein: the delivery device comprises an electromagnet and a platform comprising a dielectric material; the platform contacts the second electrode; and the electromagnet is coupled to the platform.

19. The method of claim 18 wherein: the multiple emitter openings further are configured such that shockwaves generated by the plasma source are directed through the multiple emitter openings and radially from the plasma emitter with a sum angle of up to 330 degrees; and each stand of the multiple stands comprises one of a rounded trapezoidal cross-section or a triangular cross-section.

20. The method of claim 19 wherein: the one of the rounded trapezoidal cross-section or the triangular cross-section comprises an apex angle measuring between ten and sixty degrees; and each emitter opening of the multiple emitter openings is equally sized with each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings illustrate the invention. In such drawings:

(2) FIG. 1 is a diagram of an apparatus with a plasma source of elastic oscillations placed in a well.

(3) FIG. 2 is a diagram of a plasma source of the present invention.

(4) FIG. 3 is an illustration of a calibrated metal conductor delivery device.

(5) FIG. 4 is an illustration of a bottom electrode with an axial opening for delivery of the calibrated metal conductor.

(6) FIG. 5 is a diagram of an enclosure of the device for delivering the calibrated metal conductor containing a compensation dielectric liquid.

(7) FIG. 6 is an illustration of the plasma emitter and metal stands to direct a shock wave.

(8) FIG. 7 is a cross-section of the plasma emitter and metal stands taken along line 7-7 of FIG. 6.

(9) FIG. 8 presents a table showing data on the effects of the treatment on the production capacity of various wells.

(10) FIG. 9 presents further tables showing data on the effects of the treatment on the production capacity of various wells.

(11) FIG. 10 is a schematic drawing of a ground control unit according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(12) The present invention is directed to a process and device for use in the oil and gas production industry and is intended to enhance the recovery of oil and natural gas from well sources and intake capacity of water injection wells for the increase of the intake capacity of water, carbon dioxide injection and other miscible agents.

(13) The objectives of the present invention are achieved by using a nonlinear source of wide-band, periodic, directed and elastic oscillations to stimulate gas, liquid and solid media at the resonance frequencies, while the induced response of the disturbed media cannot affect the source. The beneficial effects gained through the present invention cannot be achieved with other methods, because the conditions created in the multi-point treatment cannot be duplicated by other means. In a prior art ultrasound-induced process, the transmission is low due to scattering and diversion, limiting the effective distance. In practice, it is necessary to consider the cost of the device and operation and maintenance expenses. An operator of the inventive apparatus is not required to wear high performance safety products for hearing protection as it would be in the case of the prior art high-frequency ultrasound equipment.

(14) The plasma source of wide-band, periodic, directed, elastic oscillations is nonlinear, insofar as it releases energy stored in capacitors in the form of metallic plasma within a brief period of time in a limited volume accompanied by an increase in the temperature of 28,000 degrees Celsius and higher and a high-pressure shock wave with a pressure exceeding 550 MPa. The plasma source induces elastic oscillations having significant amplitude/power in nonlinear, dissipative and non-equilibrium media. The nonlinear source of periodic, directed and elastic oscillations is wide-band, insofar as the acoustic frequency spectrum generated by a short plasma pulse covers the band from fractions of a hertz to tens of kilohertz.

(15) The apparatus for generating nonlinear wide-band, periodic, directed, elastic oscillations consists of a ground control unit, a logging/power carrying/pushing cable and a plasma source, with the latter comprising the following details: a plasma emitter with two electrodes, a high-voltage capacitor unit generally having a voltage of 6 kV and capacity of 250 microfarads, an electronic block, a Rogovsky coil installed in an electric discharge circuit of the capacitor unit, a relay block and a device for delivering the calibrated metal conductor in an inter-electrode gap. The Rogovsky coil extends the operational life of the capacitor unit and enhances reliability and decreases energy consumption during each electric discharge cycle.

(16) The delivery device is housed in an enclosure filled with compensation dielectric liquid, and is located in the front end of the plasma source. The device for delivering the calibrated metal conductor includes a spool with the wound calibrated metal conductor and the components for transporting the conductor.

(17) To perfect the communication process between the ground control unit and the in-well plasma source, which is carried out through the logging/power cable having a limited number of cores, the plasma source is provided with an electronic block and a relay block. The logging cable carries power/signals to and from the in-well plasma source and supports its weight. The electronic block and relay block secure necessary electric schematics switching within the required time sequence.

(18) The ground control unit is equipped with an electric discharge alarm/interlock, which improves an operator's ability to act in a timely manner. The alarm/interlock controls the delivery of the calibrated metal conductor into the inter-electrode space as well as the electric discharge power, and shuts down the plasma source in case of the plasma emitter faulting. The operator of the ground control unit controls the plasma source by means of signals transmitted through the logging/power cable. The ground control unit consumes approximately 500 W, and can be powered from AC line voltage, a portable generator, a solar battery, a wind turbine, a tidal wave generator, other AC voltage source or a suitable DC voltage source.

(19) The present invention is directed to a method for treating wells/boreholes with the plasma source. The method begins with introducing the plasma source in the well followed by its subsequent submerging in the well fluid. The inventive apparatus consists of a ground control unit, a logging/power cable and a removable/changeable plasma source for placing in boreholes, wells and other man-made land openings, including those made using directional drilling, or existing natural openings. In addition, the apparatus can be used in onshore/offshore wells. To ensure the uninterrupted operation in field conditions, the apparatus is provided with a spare plasma source. The apparatus can be serviced on site and/or in the field and can be transported by an off-road vehicle, boat or any other suitable means of transportation.

(20) As illustrated in FIG. 1, a productive hydrocarbon deposit is a natural multilayer formation characterized with bulk modulus elasticity. The deposit contains non-equilibrium dissipating gas and fluid with their vertical distribution depending on the density of the fluid filling the pores. The volume of the effective pores is affected by the capillary and gravitation forces in the productive reservoir.

(21) As can be seen from FIG. 1, the inventive apparatus 12 for inducing nonlinear, wide-band, periodic, directed and elastic oscillations in the hydrocarbon deposit aimed at the EOR of wells/boreholes encompasses mobile station 14 having a ground control unit 16, a geophysical armored logging/power support cable 18 and a plasma source 20 placed in a well/borehole 22 and emits shockwaves 23 therein. The mobile station 14 is provided with an autonomous energy source and a truck-mount cable winch or similar equipment to extend and retract the support cable 18 allowing the transportation of plasma source 20 along the well 22.

(22) The support cable 18 carries power and electrical signals from the ground control unit 16 to the plasma source 20 inserted in the well 22 and carries feedback electrical signals, if necessary. In addition, the logging carrying cable 18 supports the weight of the plasma source 20 and can reach at least 5,000 (five thousand) meters in length. A pushing logging cable 18 is used for directional, non-vertical boreholes/openings 22 and those with a changeable direction. The plasma source 20 is moved up and down (in/out in vertical and directed non-vertical boreholes/openings without a horizontal completion) the well/borehole 22 using a cable truck-mount winch or other similar device that regulates the length of the logging/power cable 22.

(23) The plasma source 20 depicted in detail in FIG. 2 is provided with an adapter 24 for a hermetically sealed connection to cable 18. The upper portion of the plasma source 20 is enclosed in an impact resistant, generally cylindrical hermetic housing 26 and attached to a two-electrode plasma emitter 28 being left open. The plasma source 20 preferably has an outer diameter of approximately 3.5 inches to allow the insertion of the plasma source in conventional casing/piping. In an alternate embodiment, the outer diameter of the plasma source 20 may be approximately 2.5 inches or smaller to allow its insertion in smaller production piping, i.e., 2.75 inches in diameter.

(24) Plasma source 20 further comprises: a high-voltage transformer charger 30, electronic and relay blocks 32 that control the switching of cores in the logging/power cable 18, a power capacitor unit 34; a contactor 36 for initiating discharge of the capacitor unit 34, and the pulsed plasma emitter 28 equipped with a high-voltage first electrode 38 and second electrode 40. The transformer charger 30, electronic and relay blocks 32, capacitor unit 34, contactor 36, and first electrode 38 are attached in series by a plurality of connectors 37 as shown. The first electrode 38 is attached to the plasma emitter 28 with a plastic sleeve 42 and rubber seals (FIG. 6). The plastic sleeve 42 serves as an electric insulator and prevents the penetration of well fluid into the plasma source housing 26 at excessive pressure. Calibrated metal conductor 46 is transported by a delivery device 50 housed by enclosure 48 located in the front end of plasma source 20. Enclosure 48 (FIG. 2, 5) preferably has the same diameter as housing 26 and is attached to the plasma emitter 28 by a threaded connection. Metal enclosure 48 featuring body 52 is filled with dielectric compensation liquid 54 to prevent the influx of well fluid into the delivery device 50. Liquid 54 also cools the second electrode 40. As illustrated in FIGS. 6 and 7, the gap 56 between electrodes 38 and 40 is surrounded by three metal stands 58. The three metal stands 58 are equally spaced about the circumference of the plasma emitter 28 (FIG. 7) and are configured to direct the pressure pulse/shock wave 23 to the well and surrounding media (FIG. 1). In a preferred embodiment, the metal stands 58 each have a generally triangular shape with an apex angle 59 (the part of the triangle oriented toward the electrode gap 56) of between ten degrees and sixty degrees. Having the metal stands 58 equally spaced about the circumference of the plasma emitter 28 results in three equally sized emitter openings 57 of between sixty degrees and one hundred ten degrees. In a particularly preferred embodiment (FIG. 7), the apex angle 59 of the metal stands is forty-eight degrees resulting in three emitter openings 57 of seventy-two degrees.

(25) As illustrated in FIGS. 2-4, the delivery device 50 for delivering calibrated metal conductor 46 into the gap 56 located between electrodes 38 and 40 has a platform 60 with a flange 62 for attachment to plasma emitter 28. In accordance with FIG. 3, the following details are mounted on the platform 60 made of a dielectric material: electromagnet 64, spool 66 for storing calibrated metal conductor 46, plastic guide bushing 68 with an axial opening 70, which is pressed to bottom electrode 40. The openings in guide bushing 68 and bottom electrode 40 are adjusted accordingly for directing metal conductor 46 into the inter-electrode gap 56. The core 72 of electromagnet 64 has a frame 73 with an L-shaped push type actuator 74 having pointed edge 76. The electromagnet 64, actuator 74, and pointed edge 76 cooperate to guide the calibrated metal conductor 46 and, during the back-and-forth motion of an electric magnet plunger 78, direct the conductor 46 into the inter-electrode gap 56. The electromagnetic core 72 and the plunger 78 have axial openings 70 for transporting the metal conductor 46 from storage spool 66.

(26) The electrical discharge occurring between electrodes 38 and 40 bridged by the calibrated metal conductor 46 leads to the explosion of metal conductor 46 and the formation of a metallic plasma burst. This creates a pressure pulse/shock wave in the inter-electrode space 56 of the plasma emitter 28 that propagates out through the well fluid 10 contained in a productive hydrocarbon deposit, the energy of which is directed to the well's productive intervals by directing stands 58 of the plasma emitter 28 (FIG. 6).

(27) On an operator's command, plasma source 20 performs the following actions: actuation of the delivery device 50 to feed calibrated metal conductor 46 (FIGS. 2, 3); charging of power capacitor unit 34; starting contactor 36 initiating the electric discharge through a high-voltage circuit to electrodes 38 and 40 bridged by calibrated metal conductor 46; and a count of pulses from the plasma emitter is displayed on the panel of the ground control unit 16.

(28) The control unit 16 located in mobile station 14 sends, through cable 18, voltage pulses to electromagnet 64 of the device 50 for delivering calibrated metal conductor 46 for bridging electrodes 38 and 40 of plasma emitter 28. The required number of pulses, the frequency of plasma pulses generated by plasma source 20 being moved along the well/borehole 22 and the number of plasma pulses per point/length unit of the well is usually evaluated prior to the insertion of plasma source 20 into the well 22. The anticipated treatment schedule can be preliminarily programmed using the ground control unit 16 and can then be initiated by an operator following the insertion of plasma source 20 in the well/borehole 22 to be treated.

(29) The energy stored on capacitor unit 34 is used for generating the pressure pulse/shock wave that is initiated within the inter-electrode space 56 and propagates far beyond. First, the voltage to high-voltage transformer 30 is provided through logging/power cable 18 followed by charging capacitor unit 34. An electric signal is transmitted to electronic and relay blocks 32 through cable 18, and the blocks switch the corresponding cores of cable 18. A start signal is then transmitted to contactor 36. After the actuation of the contactor 36, a high-voltage pulse is sent from capacitor unit 34 to high-voltage electrode 38 of plasma emitter 28 through a high-voltage electric circuit. At that time, plasma emerges in the space between electrode 38 and electrode 40, and the associated spatial pressure profile emerges. The discharge registration is conducted in accordance with the signal level of a Rogovsky coil 80 installed in the electric discharge circuit 35 of capacitor unit 34.

(30) The technical characteristics of the preferred embodiment of the inventive plasma source 20 are as follows: pulse power: 1.5-2 kJ; capacitors' charging voltage: 2.5-6 kV; primary AC voltage supplied through the cable from ground power source: 80-300 V; average plasma source work cycle duration in well: 25-35 s; maximal number of pulses without lifting the source up to the surface: 2000; plasma source length: approximately 8 feet (2.5 m); plasma source outer diameter: approximately 4 inches (10 cm) or smaller; and plasma source weight: approximately 155 pounds (70 kg) or smaller.

(31) In another preferred embodiment (not shown), the plasma source 20 is designed in such a way so as to assure its flexibility required for movement along curved parts of a well 22. In this embodiment, components including transformer charger 30, electronic and relay blocks 32, capacitor unit 34, contactor 36, connectors 37, and plasma emitter 28 are secluded in separate metal/impact resistant plastic hermetical enclosures. Each component is then connected by means of flexible external electrical cable hermetically entering each enclosure. The connections can be secured with chains, belts, springs or similar equipment. The total number of individual enclosures depends on the required flexibility and electrical requirements of the components.

(32) The flexible inter-enclosure cable can be secluded in a bellows hose with the ends of the bellows being hermetically attached to corresponding enclosures. Hermetic entrance of the inter-enclosure cables into enclosures may not be required in such a case, but is still desirable as protection against the accidental rupture of the bellows. The bellows can be made of metal or other material(s), including impact resistant plastic.

(33) The components of the plasma source 20 and their parts can be connected with flexible/semi-flexible connectors 37 and placed in flexible housing 26 fabricated in the form of large bellows or can be housed by other impact-proof flexible enclosures provided with hermetic connections. Flexible bellows-like enclosures having a conical front end can be used as an enclosure for the delivery device 50. The enclosures can be fabricated from any impact-proof flexible material. Using bellows ensures the flexibility of the plasma source 20.

(34) The efficiency of the inventive process and apparatus for EOR applications is summarized in FIGS. 8 and 9. It can be immediately seen from comparing the before and after columns that the production capacity of the treated wells significantly increased following the treatment.

(35) The plasma source 20 is preferably equipped with sensors, including temperature sensors, pressure sensors, level sensors, moisture sensors, hydrocarbon detectors and/or other sensor/detecting device(s) for providing feedback.

(36) The inventive plasma source is applied in field conditions and does not require using chemical or biological agents. The plasma source generates oscillations in layer/reservoir/deposit/stratum/medium containing gases, liquids and/or solids at their intrinsic resonance frequencies, while the reciprocal force of the disturbed media is not capable of affecting the source.

(37) The well/borehole plasma source is provided with the capability to store energy on the included capacitors' unit. The plasma source releases a significant amount of energy within a tenth-of-a-microsecond burst in the form of metallic plasma, following the explosion of the calibrated metal conductor. These events are accompanied by a pressure pulse/shock wave in the well fluid with the localized temperature exceeding approximately 28,000 degrees Celsius, and the shock wave peak pressure exceeding 550 MPa. The oscillations and waves induced in the nonlinear dissipative media are characterized by significant amplitudes. The low-frequency acoustic vibrations ultimately prevail, and the coefficients of absorption, reflection and refraction undergo substantial changes.

(38) The plasma source is capable of producing wide-band, periodic, sound waves with frequencies ranging from below 1 Hz to frequencies exceeding 20 kHz. The very broad range facilitates the capture of a dominant frequency followed by the emergence of resonance oscillations in the productive deposit. Depending on the degree of attenuation and a number of other conditions, the oscillations can last for a long duration.

(39) Another distinguishing feature of the plasma source is that the device for delivering the calibrated metal conductor comprises an electromagnet, which has an axial opening for protracting the calibrated metal conductor from the storage spool. The frame, with an L-shaped push type actuator having a tapered trailing edge, is firmly attached to the magnet's core. The actuator presses the conductor to the platform, which holds all of the details of the delivery device. The calibrated metal conductor is transported through the coaxial openings in the plastic guide bush and the bottom electrode and is then brought into contact with the top high-voltage electrode.

(40) The device for delivering the calibrated metal conductor is housed in an enclosure attached to the plasma source with a threaded connection. The enclosure is filled with compensation liquid for preventing well fluid from entering into the delivery device and for cooling the bottom electrode. The enclosure is shaped as a cone, for example, a tapered cone, to minimize the clinging of the source in the well.

(41) The calibrated metal conductor is transported into the inter-electrode spacing using the delivery device located in the metal enclosure. The conductor is made of a metal, an alloy, a metal-containing composite or other electrically conducting material for forming the metallic plasma and sustaining plasma chemical reactions, if desired. These reactions can include the transformations of organic compounds, catalytic processes and metal-organic reactions.

(42) The preferable diameter of the conductor is 0.3-0.9 mm and can vary substantially, depending on the material's properties and required plasma parameters.

(43) The discharge circuit of the capacitor's unit is provided with a Rogovsky coil for registering the current on the capacitors' storage discharge circuit and creating an electric signal for the pulse counter.

(44) As schematically shown in in FIG. 10, the ground control unit 16 of the inventive apparatus is provided with a discharge alarm/interlock 82. It allows the operator to control the pitch of the metal conductor 46 drawing through the opening 70 in the bottom electrode 48 for bridging the gap 56 between the two electrodes 38, 40. The alarm/interlock 82 controls the discharge level, and will shut down the plasma source 20 should the plasma idle. The control unit 16 can be controlled with a computer, including a remote computer, cell phone or other remote device(s).

(45) The control unit 16 of the plasma source 20 is provided with an electronic voltage stabilizer 84, a power supply 86 featuring an incremental adjustment 86a of the output voltage and a recording block 88 for registering well/borehole/reservoir treatment conditions.

(46) The treatment of a well/borehole/reservoir with the inventive source can be performed using a series of pulses at a fixed location in the well. Alternatively, the following stimulation can also be utilized: a series of pulses performed at different locations in the well or periodic generation of plasma emission with the source being moved along the well. The number of pulses applied over the treatment's course, the source's position in the well/borehole and/or the speed of the source movement in the well depends on the treatment's goal.

(47) Although several embodiments have been described in detail, for purposes of illustration, various modifications may be made without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited, except as by the appended claims.