RU2477370C1 - Submerged-type electric pulse drill - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: submerged-type electric pulse drill is intended for drilling of wells and driving of shafts in hard mine rocks destructed with high-voltage discharges developed in them, and can be used in mining industry. Drill head (6) is attached to lower flange of drill (2) housing. In drill (2) housing there coaxially installed is washing pipeline (1) that is passed through the drill cover plate (3) and high-voltage insulator (5) provided with insulation ribs (8), which are inclined towards drill head (6), which provides collection of impurities in annular sump tank (9) and their removal from the drill through discharge valve (10) by increasing the gas pressure in it, thus multiply increasing the service life of insulation elements of the drill. It is facilitated with the diameter of lower high-voltage insulator (5) exceeding its support rib (7) in comparison to inner diameter of mounting flange (11). In order to increase the drill service life and reduce the time required for its maintenance, high-voltage pulse source is made as per Arkadyev-Marx scheme, capacitors (17) of which are arranged around washing pipeline (1) and assembled to detachable capacitor sections, each of which includes one or more capacitors (17), two buses (19), two charge elements and support insulator (20).

EFFECT: invention allows increasing the service life of the device, simplifying its maintenance, and removing and re-installing individual detachable parts without complete removal of the generator.

3 cl, 3 dwg

Description

The invention relates to technical means for drilling boreholes and sinking shafts using high-voltage pulsed discharges that develop directly in the rock, and can find application in the mining industry for sinking boreholes and shafts in hard rocks hundreds of meters deep. The invention can also be used for drilling wells in the oil and gas industries.

Known electropulse submersible drill, considered in the description of the magnetic thyristor pulse generator (patent for invention RU No. 2315421, IPC 8 Н03К 3/00, publ. 20.01.2008), which includes the housing of the pulse generator, which is simultaneously the body of the drill, to the lower end which is attached a drill bit with spark gaps between bipolar electrodes, a pipe for supplying flushing fluid to the bottom of the well, installed along the axial line of the casing and separated from it by a high-voltage insulator, and immersed in an electrical a pulsation generator containing magnetic compression links and connected in series with a primary capacitive storage device, a thyristor switch, an input pulse transformer; the power source of the pulse generator (not shown) is connected in parallel with the thyristor switch, the first compression link is formed of two series-connected capacitors and an input pulse transformer. The generator also contains an output pulse transformer with a ferromagnetic core, the primary winding of which is formed by the housing, and the secondary sector windings are laid in a spiral, and a single-layer cone-shaped demagnetization coil connected by one output to the common point of the sector windings and by the other terminal to the primary winding of the input pulse transformer.

One of the disadvantages of this device is the low reliability of the high-voltage insulator due to the single-layer cone-shaped demagnetization coil located in it, because coil turns create high gradients of the electric field, which causes a rapid deterioration in the properties of the material of the insulator and accelerates its electrical breakdown. In addition, generators, similar to that used in this device, generate high voltage pulses with parameters insufficient for efficient electric pulse drilling.

Closest to the proposed device in terms of design features and the achieved positive effect is an electric pulse submersible drill, described in the description of a submersible electric discharge generator (patent for invention RU No. 2340081, IPC 8 Н03К 3/53, publ. 11/27/2008), including a generator housing with a jacket, which is also a drill body, to the lower end of which a working tool (drill bit) is attached with spark gaps, a central channel (pipe) for supplying flushing fluid to the bottom of the wells they are separated from the housing by the upper (inside of the spark gap electrodes) and lower (above the working tool) insulators, as well as a pulse generator located in the housing, containing a strip forming line connected to a multichannel uncontrolled spark gap and a pulse transformer, to the secondary winding of which through matching a working tool is connected to the coaxial line, and the multi-channel spark gap is made with radially converging anode electrodes covered by ferromagnetic cores and distributed laid around the cylindrical cathode, the ferromagnetic cores are covered by counter-parallel short-circuited turns, the electrodes of the strip forming line are divided into several parts-plates (each with the output in the center of the plates), laid in a spiral Archimedes around the central channel on a base made of dielectric, potential plates are connected to the cathode of the spark gap, and others to the common point of connection of the primary and secondary windings of the pulse transformer, the internal cavity of the spark gap is filled with gas pressure, and the space in the housing under this spark gap from the lower insulator is filled with dielectric fluid (transformer oil).

One of the disadvantages of this electropulse submersible drill-prototype is the low reliability of its operation. This is due to the fact that the products formed during the operation of a multichannel uncontrolled spark arrester settle on the lower inner surface of the insulator of the arrester and lead to the development of electric discharges over its surface. Removing these products without disassembling the drill is not possible. In addition, the pollution products present in the transformer oil and formed during the development of individual electrical discharges in it, settle on the entire surface of the lower insulator and lead to the breakdown of this insulator. Such contaminants can also be removed only when the drill is completely disassembled. Another disadvantage of the drill prototype is the complexity of its maintenance, because for inspection, adjustment, replacement of any part, except for the parts of the working tool, it is necessary to completely drain the transformer oil each time and remove all parts from the housing (in the assembly).

The main technical result of the proposed solution is that the service life of this drill without emergency disassembly is many times higher than that of the prototype drill, because it constructively provides for the collection of pollution products in an annular dirt collector and their periodic removal without disassembling the drill. In this case, the collection of pollution products in the storm occurs at a maximum distance from its elements under high voltage. Another technical result is to simplify the maintenance of the drill, because it is easier to bleed gas than to pour, collect and clean oil for repeated use. In addition, the design of the drill allows you to quickly remove and put in place individual removable condenser sections or capacitors without completely disassembling the generator.

A new technical result is achieved in that in an electropulse immersion drill containing a coaxially located flushing pipe and a drill body, a drill tip is mechanically and electrically connected to its lower end, above which in the gap between the drill body and the flushing pipe, between the high-voltage lower insulator and the drill cover placed a source of high voltage pulses placed in an insulating medium, according to the proposed solution, as an insulating medium sources and high-pressure pulses applied gas under pressure, and part of the high-voltage lower insulator located in the insulating medium above its support rib is made with insulating ribs inclined towards the drill tip, under which there is an annular dirt collector, and the source of high-voltage pulses is made according to the Arkadyev scheme Marx and its capacitors are placed around the flushing pipe in the form of removable condenser sections, and the charging elements connected between the capacitors Nena in the form of inductive coils with ferromagnetic cores.

It is advisable to make the annular dirt collector removable, and to provide the drill with one or more relief valves.

It is also advisable to carry out the high-voltage lower insulator so that the diameter of the insulator above its support rib is larger than the inner diameter of the pressure flange located under the support rib.

An example of a specific implementation. Figure 1 shows a longitudinal section of the proposed electric pulse submersible drill, figure 2 shows its cross section passing through the capacitors of the section, and figure 3 presents a photograph of a removable capacitor section.

The electropulse submersible drill contains a coaxially located flushing pipe 1 made of fiberglass and a steel drill body 2. The upper end of the drill is closed by a cover 3 through which the flushing pipe 1 is passed and on which a high-voltage input 4 is fastened, through which the capacitor sections are charged. In the lower part of the drill case 2, a high-voltage lower insulator 5 is inserted into it with the upper end, and the lower end of this insulator is an insulator of a drill bit 6 made of material Steel 20 according to the invention patent (RU No. 2409735, IPC ЕВВ 7/15, Е21С 37 / 18, published on January 20, 2011, Bull. No. 2). Perhaps the use of drill bits and other designs. The part of the high-voltage lower insulator 5 located above its supporting rib 7 is made with insulating ribs 8 inclined towards the drill bit 6, under which there is an annular dirt collector 9 and one or more relief valves 10. The diameter of the high-voltage lower insulator 5 above its supporting rib 7 is larger the inner diameter of the clamping flange 11, made in the form of a ring and located under the support rib 7. This prevents the destruction (cutting) of the support rib 7 by vertical loads. The clamping flange 11 is located above the supporting flange 12, which is part of the grounded electrode system of the drill bit 6, which is attached with pins to the lower flange 13, which is rigidly connected (by electric welding) to the bottom-hole end of the drill case 2. The high-voltage lower insulator 5 is equipped with a tubular high-voltage current lead 14, worn on the lower end of the flush pipe 1. To ensure the tightness of the gap between the current lead 14 and the flush pipe 1, a sealing ring 15 is located under the current lead, and the upper end of the lead ene nut 16 serving to compress the sealing ring. In the gap between the body of the drill 2 and the flushing pipe 1, between the high-voltage lower insulator 5 and the cover of the drill 3 there is a source of high-voltage pulses made according to the Arkadyev-Marx scheme (V.V. Kremnev, G.A.Mesyats. Methods of multiplication and transformation of pulses in high-current electronics. Chapter 2.1. Generators assembled according to the Arkadyev-Marx scheme. Novosibirsk, Nauka, 1987. P.33, Fig. 2.1). Capacitors 17 of this source are placed around the flushing pipe 1, between the capacitors included charging elements 18 (figure 2), made in the form of inductive coils with ferromagnetic cores. Details of the source of high voltage pulses are arranged in the form of removable capacitor sections (Figs. 1-3), each of which contains two buses 19, between which one or more capacitors 17 are fixed, two charging elements 18 and a support insulator 20, freely worn on the flushing pipe 1, which makes it easy to mount each condenser section on the flushing pipe and remove from it. In each capacitor section with the help of tires 19 (tires are shown in figure 1) five capacitors are connected in parallel (figure 2). This is due to the fact that the capacitance of one capacitor 17 is 0.022 μF. In order to obtain 0.11 microfarads in each section, five identical capacitors were used in them 17. The spark gap electrodes 21 made of a tungsten-cobalt alloy are mounted on vertically arranged insulating (fiberglass) rods 22, which make it possible to control the discharge gap by moving (rotation ) one of these rods without violating the tightness of the drill. A screen 23 is additionally placed under the lower (last) capacitor section to equalize the electric field at the output of the high-voltage pulse source. As an insulating medium in the internal cavity between the drill case 2 and the flushing pipe 1, gas under pressure 24, in particular nitrogen, is used. It is possible to use, for example, dried air under pressure.

The work of the proposed electric pulse submersible drill is as follows. The drill is filled with nitrogen at a pressure of 10 atm and using a drill pipe string (not shown) is installed on the bottom of the well. For the removal of sludge and gaseous products formed during the development of high-voltage discharges in the rock (granite), a dielectric flushing fluid, such as diesel fuel, is supplied to the bottom of the well through the flushing pipe 1 (Fig. 1). The body of the drill 2 is grounded. Then, from a charger (not shown) located on the surface of the day or in the well above the drill, through the high voltage input 4, a rectified voltage of 37 kV is supplied to the high voltage pulse source through the capacitor buses 19. Moreover, as in all generators assembled according to the Arkadyev-Marx scheme, the capacitors 17 are charged in parallel through the charging elements 18 (Fig. 2). During the subsequent sequential breakdown of the gaps between the electrodes of the arresters 21, the capacitors of the capacitor sections are connected in series, the voltage is multiplied (depending on the number of capacitor sections) and the capacitors are quickly discharged to the load, i.e. on the rock between the high-voltage and grounded electrodes of the drill bit 6. The fast charge of the capacitors and increase the efficiency of the source of high-voltage pulses contributes to the implementation of the charging elements 18 in the form of inductive coils with ferromagnetic cores. Products formed during electrical breakdowns of the gaps between the electrodes of the arresters 21 and polluting the gas settle down in the annular dirt collector 9 and partially on the insulating ribs 8 inclined towards the drill bit, from which they enter the dirt collector during the development of electrical discharges in the rock, because . at each such discharge, the entire drill vibrates. To remove products from the dirt collector 9, the gas pressure 24 in the storm is raised above the working one: from 10 atm to 11 atm, which causes the relief valve 10 or several such valves to work, and the impurities are blown from the internal cavity of the drill into the annulus. If necessary, the sump is removed and cleaned or replaced with another.

Using a drill bit with a diameter of 360 mm with an amplitude of high-voltage pulses of 360 kV and a capacitance in the discharge of 0.011 μF, several meters of wells were drilled in granite blocks. When several hundred thousand high-voltage pulses were applied, the lower insulator 5 did not fail, i.e. there are no traces of its electrical breakdown and the development of discharges on the surface; no mechanical damage. No electrical breakdowns of gas were also observed 24. The drill prototype failed even when several tens of thousands of impulses were supplied and required its complete disassembly to replace failed insulators.

Claims (3)

1. An electropulse submersible drill bit, comprising a coaxially located flushing pipe and a drill body, a drill tip mechanically and electrically connected to a lower end above which a source of high voltage pulses is placed in the gap between the drill case and the flushing pipe, between the high-voltage lower insulator and the drill cover, placed in an insulating medium, characterized in that as an insulating medium of a source of high voltage pulses applied gas under pressure, the part of the high-voltage lower insulator located in the insulating medium above its supporting rib is made with insulating ribs inclined towards the drill tip, under which there is an annular dirt collector, and the high-voltage pulse source is made according to the Arkadyev-Marx scheme, and its capacitors are located around the flushing pipe in in the form of removable capacitor sections, and the charging elements included between the capacitors are made in the form of inductive coils with ferromagnetic cores s. 2. Electropulse submersible drill according to claim 1, characterized in that the annular dirt collector is removable, and the drill is equipped with one or more relief valves. 3. Electropulse submersible drill according to claim 1, characterized in that the diameter of the high-voltage lower insulator above its support rib is larger than the inner diameter of the pressure flange located under the support rib.

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