RU2529067C1 - Device for well bottom flushing - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: device comprises cylindrical case with inner cavity, thrust ring and valve. Said cylindrical case can be secured to tubing. Note here that case thrust ring has high-pressure channel for hydraulic communication of cylindrical cavity with hole annuity. Half the circumference of cylindrical case bottom end is composed by saw-like ripper while another half has skew cut. Case thrust ring on ripper side has at least two high-pressure channels, aligned with case axis. Hole is made in the case thrust ring on skew cut side, off centre of case axis. Valve arranged inside the case opposite said bore to allow the down-up flow is composed of valve box with ball fitted in thrust ring bore. Valve box is rigidly secured to thrust ring.

EFFECT: higher reliability and efficiency of flushing.

3 dwg

Description

The proposal relates to the oil and gas industry and can be used for overhaul and maintenance of oil and gas production and injection wells associated with cleaning their faces from sand and proppant plugs, formation mud.

A device for washing a well is known (patent RU No. 2047740, IPC ЕВВ 37/00, publ. 10.11.1995), comprising a hollow body with an inlet channel, a tip with an axial channel rigidly attached to the hollow body, and a hydrodynamic pulse generator coaxially disposed therewith hydraulically connected through the axial channel to the input channel, while it is equipped with additional generators of hydrodynamic pulses located at the tip around the circumference relative to the axial channel and hydraulically connected to the input channel, with each gene the hydrodynamic pulse ator is made in the form of a sequentially placed confuser, a critical hole and a diffuser, moreover, the device is equipped with a fairing installed in the tip, and on the inner surface of the housing in the location of the fairing a multi-start screw channel is made, and the multi-start screw channel is made three-way, and inclined in the case guide channels hydraulically connected to the input channel and confusers of additional generators.

The disadvantages of this device are:

- firstly, the complexity of the design, due to the large number of nodes and parts;

- secondly, the complexity of manufacturing (confuser, diffuser. multi-helical channel, etc.) and, accordingly, the high cost of the finished product;

- thirdly, low washing efficiency in the presence of solid deposits at the bottom of the wells.

Also known is a device for cleaning the bottom-hole zone of a well (a.s. SU No. 1790662, MPK ЕВВ 21/00, published on January 23, 1993) containing a tubing string equipped with non-return valves and a perforated “feather” in the lower part. The descent of the pipe string into the well is carried out with the introduction of a perforated pen into the surface of mechanical impurities. The flushing fluid is fed into the annulus of the well, mechanical impurities in the well, such as a sand plug, are destroyed by longitudinal mechanical vibrations of the column, and the washing fluid with washed out mechanical impurities is lifted to the surface through the pipe string.

The disadvantages of the device are:

- firstly, the low efficiency of the destruction of uncleared mechanical impurities, especially in the case of solid phases in the tube;

- secondly, the high accident rate of this technological operation associated with the rubbing of the production string and tubing string in the process of mechanical vibrations of the latter, especially in directional wells with a large deviation angle.

The closest in technical essence is a device for washing the bottom of the well (patent RU No. 2271433, IPC ЕВВ 21/00, publ. 03/10/2006, bull. 7), containing a cylindrical body with a cavity and a valve, which can be connected to the pipe string moreover, in the housing end and radial hydraulic monitor channels are made for hydraulic communication of the specified cavity with the annular space, located at an angle to the axis of the housing, the valve being made in the form of a curtain pivotally connected to a thrust ring hermetically fixed inside In case of the device’s body, and having the possibility of tightly pressing it against the thrust ring when the flushing fluid is injected into the pipe string and opening it when the flushing fluid is injected into the annulus, the curtain channels are made of hydromonitor channels, and the shutter is made of a steel plate 12-15 mm thick in which one central hydraulic monitoring channel and three hydraulic monitoring channels are arranged uniformly at an angle of 120 ° around the circumference and directed from the axis outward at an angle of 20 ° relative to the axis of the housing, and d the diameter of the hydraulic monitoring channels is 4 mm, while in the upper part of the housing there are three radial hydraulic monitoring channels located uniformly around the circumference and directed upward - outward at an angle of 25 ° relative to the axis of the housing, and a thread is made in the upper part of the housing to connect it to the pump compressor pipes, and the lower end of the housing is sawtooth.

The disadvantages of this device are:

- firstly, the low reliability of the design, due to the fact that the valve is made in the form of a curtain pivotally connected to the thrust ring, therefore, there is a high probability of breakage of the hinge and failure of the device;

- secondly, the low efficiency of washing the bottom of the well, which is associated with a loose fit of the shutter on the thrust ring, since during the hydromonitor impact on the leached rock, sand particles settle on the mating surface of the shutter and thrust ring.

An object of the invention is to increase the reliability of the device and the efficiency of washing the bottom of the well.

The stated technical problem is solved by a device for washing the bottom of the well, comprising a cylindrical body with a cavity, a thrust ring and a valve, the cylindrical body having the ability to connect to the pipe string, while the thrust ring of the cylindrical body has hydraulic monitor channels for hydraulic communication of the cavity of the cylindrical body with the annulus .

What is new is that half of the circumference of the lower end of the cylindrical body is made in the form of a sawtooth cultivator, and the other half of the lower end of the cylindrical body is equipped with an oblique cut, while at least two hydromonitor rings are made eccentrically to the axis of the cylindrical body along the circumference of the cylindrical body of the cylindrical cultivator. channels, and in the thrust ring of the cylindrical body from the side of the oblique cut eccentric to the axis of the cylindrical body, a hole is made, and in the cavity the cylindrical body opposite the opening a valve that passes from bottom to top and made in the form of a ball valve cage mounted in the thrust ring opening, wherein the valve cage is fixedly secured to the thrust ring.

Figure 1 schematically in longitudinal section shows a device for washing the bottom of the well.

Figure 2 shows a section aa of the device.

Figure 3 shows a top view of the thrust ring of the device.

The device for washing the bottom of the well contains a cylindrical body 1 (see figure 1) with a cavity 2, a thrust ring 3 and a valve 4.

The cylindrical housing 1 has the ability to connect to the tubing string 5, for example, to the tubing string.

One half of the circumference 6 (see FIG. 2) of the lower end of the cylindrical body 1 (see FIG. 1) is made in the form of a sawtooth ripper 7, and the other half of the circumference of the lower end of the cylindrical body 1 is equipped with an oblique cut 8.

In the thrust ring 3 of the cylindrical body 1 from the sawtooth cultivator 7 of the cylindrical body 1 along the circumference 9 (see FIG. 3) there are made at least two hydraulic monitor channels, for example, four hydraulic monitor channels 10 '; 10 "; 10 '"; 10 "" diameter d each. A minimum of two hydraulic monitoring channels are necessary for effective action of the jets.

Monitor channels 10 '; 10 "; 10" '; 10 "" hydraulically communicate the cavity 2 (see figure 1) of the cylindrical body 1 with the annular space 11.

In the thrust ring 3 (see FIGS. 1 and 3) of the cylindrical body 1, an opening 12 with a diameter D is made eccentrically to the axis of the cylindrical body 1 from the side of the oblique slice 8. A valve 4 is installed in the cavity 2 of the cylindrical body 1 opposite the opening, passing from the bottom up and made in the form of a valve cage 13 with a ball 14 installed in the hole 12 of the thrust ring 3. The valve cage 13 is rigidly fixed to the thrust ring 3. The diameter of the cylindrical body 1 is determined by the design of the well and the diameter of the pipes.

The area of the bore holes d and D must comply with the following condition:

$$k\cdot n\cdot (\pi \cdot d^2/\mathrm{four}<(\pi \cdot D^2/\mathrm{four}),\text{(one)}$$

where k is the coefficient providing a hydromonitor effect on solid deposits of contaminants through hydromonitor holes with a diameter of d. It was experimentally obtained that k = 10-12, we take k = 12;

d - monitor channels, for example, diameter d = 4 mm;

n is the number of monitor channels with a diameter of d, performed in the thrust ring 3, for example, in the thrust ring around the circumference perform four monitor channels with a diameter of d;

D is the diameter of the hole, mm. Substituting numerical values into condition (1), we determine the minimum diameter of the hole 12 of the thrust ring 3.

12- 4 (3.14 (4 mm) ^2/4) <(π · D _2/4),

602.88 mm <(π · D _2/4)

D> √ (602.88 mm4) / 3.14

D> 28 mm

We take the diameter D of the hole 12 to be 30 mm.

Arrangement of hydraulic monitor channels 10 '; 10 "; 10 '"; 10 "" along the axis 9 of the thrust ring 3 is due to the fact that the maximum impact of a jet of liquid jet falls within the interval 15 of the impact of the sawtooth ripper 7 on solid deposits 16.

The principle of operation of the device is based on the rotation of a cylindrical body 1, equipped with a sawtooth ripper 7 from below and on the use of high pressure jets of washing liquid, which together leads to the destruction and grinding of solid deposits 16 (proppant, sand, etc. plugs) in combination with the removal of destruction products by washing backwash. A minimum of two hydraulic monitoring channels is necessary for the effective action of high pressure jets of washing liquid on solid deposits 16 when exposed to a sawtooth ripper 7.

The device operates as follows.

The device (see Fig. 1) is connected to the tubing string 5 by means of a thread (not shown in Figs. 1, 2, 3) made on the upper end of the cylindrical body 1, and lowered into a washed well to hard deposits 15, for example, a sand plug, which must be destroyed.

For example, a tubing string 5 with a diameter of 89 mm and a diameter of a cylindrical body 1 of 118 mm, with an oblique cut 8, for example, at an angle α = 35 ° to its axis to the stop, is lowered into a well 17 with a production casing diameter equal to 168 mm in hard deposits in the range of 1150 m.

Simultaneously rotate the tubing string 5, for example, clockwise at a speed of 20 rpm and pump the flushing fluid through the tubing string 5 into the cavity 2 of the cylindrical body 1 and the hydraulic channels 10 '; 10 ";10"';10"". As a washing liquid, for example, wastewater with a density of 1100 kg / m ^{3 is used} .

As a result, flushing fluid jets flowing out of the monitor channels 10 ′; 10 "; 10" '; 10 "" under high pressure, act in the interval 15 at the sawtooth ripper 7, effectively destroying solid deposits 16.

The rotation of the tubing string 5 is produced, for example, using a suspended hydraulic wrench (not shown in FIGS. 1, 2, 3) from the wellhead 17 (see FIG. 1). In the process of pumping the flushing fluid through the tubing string 5, valve 4 is closed, since the ball 14 is pressed against the hole 12 under the pressure of the flushing fluid in the tubing string 5. The presence of a sawtooth ripper 7 improves the washing efficiency of the well 17 with solid deposits 16 due to loosening of solid deposits 15 by rotation of the tubing string 5. The rotation of the tubing string 5 with the injection of washing fluid through the tubing string 5 2 is continued until unloading on hard deposits 16 wells 17 of the weight of the tubing string 5 by 15 kN, after which the rotation of the tubing string H is stopped T 5 and pumping the wash liquid through tubing 5.

For example, the suspension weight of the tubing string 5 in the borehole 17 before stopping in the hard deposits 16 is 100 kN, therefore, the rotation of the tubing string 5 and pumping of flushing fluid along the tubing string 5 is continued until unloading on the hard deposits 16 of the well 17 the suspension weight of the tubing string 5 by 15 kN , i.e. upon reaching the suspension weight of the tubing string 5 equal to 85 kN, after which the process of rotation of the tubing string 5 and pumping of washing liquid through it is stopped. The change in weight of the tubing string 5 is fixed by the weight indicator on the lifting unit (not shown in Figs. 1 and 2).

Unloading the tubing string 5 (see Fig. 1) by 15 kN avoids the possible sticking of the pen during the flushing of the well 17.

The flushing direction is switched to the opposite and the flushing fluid is injected into the annulus 11, for example, at a flow rate of 8 l / s under pressure not exceeding the allowable for the production casing of the well 17, for example, at a pressure of 7 MPa, with an allowable pressure on the production casing of 9 MPa lifting the loosened washed-out sludge along the tubing string 5 to restore the suspension weight of the tubing string 5, i.e. up to 100 kN.

In the process of pumping the flushing fluid through the annular space 11 of the well 17, the valve 4 opens, since the ball 14 rises up and presses against the valve cage 13 under the pressure of the flushing fluid, while the washed slurry with the flushing fluid is passed from the bottom up through the hole 12 of a larger diameter and through valve cell 13 and cavity 2 enters the tubing string 5, which rises to the surface, eroding hard deposits 16 and entraining its constituent materials.

After recovery of the weight of the suspension of the tubing string 5, i.e. up to 100 kN, and the appearance of a “clean” (transparent, without sand and dirt impurities) washing fluid, the pumping of the washing fluid into the annulus 11 of the well 17 is stopped.

Next, the technological operations are sequentially repeated as described above, starting from the simultaneous rotation of the tubing string 5 with the injection of flushing fluid through the tubing string 5 to the restoration of the weight of the tubing string 5 when the flushing fluid is pumped through the annulus 11 (backwash) until the solid deposits 16 are completely removed.

The proposed device for flushing the bottom of the well can improve the reliability of the device due to a more perfect valve design in comparison with the prototype (the absence of a hinge eliminates the possibility of breakage) and the effectiveness of flushing the bottom of the well, which is achieved by combining a jet flushing with rotation of a cylindrical body equipped with a sawtooth bottom cultivator.

Claims (1)

A device for washing the bottom of the well, comprising a cylindrical body with a cavity, a thrust ring and a valve, the cylindrical body having the ability to connect to the pipe string, while in the thrust ring of the cylindrical body there are hydraulic monitoring channels for hydraulic communication of the cavity of the cylindrical body with the annulus, characterized in that that half the circumference of the lower end of the cylindrical body is made in the form of a sawtooth ripper, and the other half of the lower end of the cylindrical of the casing is equipped with an oblique cut, while in the thrust ring of the cylindrical casing from the sawtooth cultivator eccentrically to the axis of the cylindrical casing, at least two hydraulic channels are made around the circumference, and in the thrust ring of the cylindrical casing from the side of the oblique cut eccentrically to the axis of the cylindrical casing opposite the hole, a valve is installed that lets it pass from the bottom up and is made in the form of a valve cage with a ball installed in the hole of the thrust sealing rings, and the valve cage is rigidly fixed to the thrust ring.

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