RU2557283C1 - Method of cleaning and maintenance of wells and pipelines - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method presumes the action in view of types of deposits on the cleaned surface by setting of the respective values of physical parameters of the effecting working medium, geometry of a cavitator and its position with reference to the cleaned surface: $$\overline{x},$$

P_c and Ps, where $$\overline{x}$$

- relative distance from the cavitator outlet to the cleaned surface, P_c - dynamic pressure downstream the cavitator, Ps - static pressure in the flooded cavity. Values of the parameters $$\overline{x}$$

and Pc are pre-set within the limits: $$\overline{x}=5-\mathrm{50,}$$

P_c=5-45 MPa. Static pressure P_s in the flooded cavity is pre-set according to the condition $$P_s=\mathrm{0,075}{P}_c\exp (-\mathrm{0,4}\sqrt{\overline{x})}$$

with providing of pulsation of the jet cavitating flow with a variable frequency and achievement of a resonance of layers of deposits. The pulsation of the jet cavitating flow is provided using a sweep generator. Occurrence of resonance of layers of deposits is identified by growth of concentration of pollution of destroyed layers in the taken-away flow, the frequency of pulsation of the jet cavitating flow is registered, at this frequency the cleaned surface is processed further.

EFFECT: improvement of efficiency of cleaning and maintenance of wells and pipelines increases.

9 cl, 5 dwg

Description

The invention relates to the field of operation of boreholes and is intended to restore efficiency and flow rates of water and producing oil and gas wells, and can also be used for cleaning pipelines.

The invention allows you to configure the hydrodynamic equipment with optimization of the hydrodynamic parameters of jet supercavitation flows using cavitation pathogens to achieve supererosion destruction of various materials in the form of layered deposits, contaminants and growths in wells and pipelines.

A known method of cleaning filter pipes of wells (RF patent No. 2061844, IPC 37/08 from 08/05/1998), including multiple hydrodynamic effects on the filter pipe by liquid pulses created by pumping liquid through a cavitation generator, and the parameters of the generated hydrodynamic pulses are controlled by simultaneously interrupting fluid flow and / or a change in its speed, and / or a change in the configuration of the flow.

There is also a method of intensifying the influx of hydrocarbons from productive reservoirs of wells (RF patent No. 2448242, IPC 43/18 of 12/07/2010), which includes equipping the bottom of the pipe string with a cavitating device, lowering the pipe string into the wellbore with installing a cavitating device in the perforated part of the wellbore and pumping in conditions of depression on the working fluid layer through the pipe string into a cavitating device with the release of high-speed jets of working fluid from the outlet openings of its channels uniformly distributed around the circumference, perpendi the ural axis of the wellbore to effect cavitation-wave action on the perforated formation while translating the pipe string, and the cavitating device is equipped with at least one multichannel jet apparatus, which ensures the formation of curved flows of the working fluid with the ejection of jets in radial directions to the walls of the wellbore wells with a step of the outlet openings of their channels, at least not exceeding the diameter of the perforation channels, while using cavitation equipment stroystva coaxially allocatable N multichannel jet apparatus the outlet openings of each channel are displaced relative to each other in radial planes wellbores to 1 / N of steps.

The closest in technical essence to the proposed technical solution is the known method of hydrocavitation erosion destruction of growths and deposits, as well as rocks in the aquatic environment (RF patent No. 2315848, IPC E21B 7/18; E21C 37/00 dated 12/28/2005), including filing to the inlet of the hydro-cavitation device of water under pressure, the activation of the hydro-cavitation process inside this device using the cavitation body located there and the direction of the cavitating stream of water from the output of this device to the surface to be destroyed, and during the course of the device, they provide a pressure of 90 to 200 atmospheres, at the initial stage, the space is artificially filled with water in front of the surface to be destroyed to a height of 300 mm water column, then the distance from the exit section of the device to the surface to be destroyed is provided in the range of 20 to 1500 mm, and a hydro-cavitation process is formed maximum power and representing a vibrational supercavitation with local heating of the medium, ionization of water and cavitation erosion of the destructible surface, which ensures Artificial formation of forced oscillations of the water flow, for which it is directed inside the hydro-cavitation device in two different ways, the first through two-stage chambers with different cross sections of these steps, and the second through a hollow cavitation body in the form of a confuser, fixed in this chamber, then both of these water jets are mixed in a nozzle at the outlet of the device, while the existence of vibrational supercavitation is determined according to the formula

(P _n / P _o ) (l _o / d _o ) ≤0.8,

where P _n / P _o is the cavitation number, defined as the ratio of the hydrostatic pressure around the flowing water stream to the destructible surface (Pn) to the total pressure at the outlet of the hydro-cavitation device (Po);

l _o is the distance from the exit slice of the device to the fracture surface;

d _o - the smallest cross-sectional diameter of the hydro-cavitation device.

However, the known methods for cleaning and restoring the health of wells and pipelines are insufficiently effective, since their implementation does not take into account the totality of the physical parameters of specific types of materials of layered deposits and contaminants and does not make the optimal choice of the parameters of the working process of exposure to the surface being cleaned.

The technical result, which consists in increasing the efficiency of cleaning and restoring the health of wells and pipelines, is achieved in the proposed method, based on the impact on the surface being cleaned with a liquid working medium in a state of cavitating vibrating flow created by the cavitator, so that the effect on various types of deposits pollution and growths on the surface being cleaned is carried out taking into account the types of deposits, pollution and growths on the surface being cleaned by setting the corresponding the corresponding values of the physical parameters of the working medium, the cavitator geometry and its position with respect to the surface being cleaned:

, P_o и Pc, где $$\overline{x}$$

- относительное расстояние от выхода кавитатора до очищаемой поверхности, P_o - динамическое давление на выходе кавитатора, Pc - статическое давление в затопленной полости, при этом $$\overline{x}=\raisebox{1ex}{$l$}\!\left/ \!\raisebox{-1ex}{$d_0$}\right.$$

, где l - расстояние от выхода кавитатора до очищаемой поверхности, d_o - диаметр проходного рабочего сечения кавитатора, причем значения параметров $$\overline{x}$$

и P_o задают в пределах: $$\overline{x}$$

, P _o and Pc, where $$\overline{x}$$

is the relative distance from the exit of the cavitator to the surface being cleaned, P _o is the dynamic pressure at the exit of the cavitator, Pc is the static pressure in the flooded cavity, while $$\overline{x}=\raisebox{1ex}{$\mathrm{<figure-callout\; id="0"\; label="l\; d"\; filenames="00000047.png,00000048.png"\; state="\{\{state\}\}">l\; </figure-callout>}$}\!\left/ \!\raisebox{-1ex}{$d_{}$}\right.$$

where l is the distance from the exit of the cavitator to the surface being cleaned, d _o is the diameter of the passage through the working section of the cavitator, and the parameter values $$\overline{x}$$

and P _{o are} set within:

, P_o=(5-45) МПа, $$\overline{x}=5-\mathrm{fifty}$$

, P _o = (5-45) MPa,

с обеспечением пульсации струйного кавитирующего потока с переменной частотой и достижением резонанса слоев отложений.and the static pressure Pc in the flooded cavity is set in accordance with the condition $$P_c=\mathrm{0,075}{P}_o\exp (-0.4\sqrt{\overline{x})}$$

providing pulsation of the jet cavitating flow with a variable frequency and achieving resonance of the layers of the deposits.

, P_o=(12-20) МПа, для наростов в виде известняка задают $$\overline{x}=10-40$$

, P_o=(5-15) МПа, для глинистых наслоений задают $$\overline{x}=5-10$$

, P_o=(10-15) МПа, для песчаных наслоений задают $$\overline{x}=40-50$$

, P_o=(5-10) МПа, для отложений в виде стойких ржавчины и накипи задают $$\overline{x}=10-40$$

, P_o=(30-45) МПа. для цемента с песком задают $$\overline{x}=25-40$$

, P_o=(10-20) МПа.Moreover, for deposits in the form of loose rust and scale $$\overline{x}=40-\mathrm{fifty}$$

, P _o = (12-20) MPa, for growths in the form of limestone set $$\overline{x}=10-40$$

, P _o = (5-15) MPa, for clay layers $$\overline{x}=5-10$$

, P _o = (10-15) MPa, for sandy layers $$\overline{x}=40-\mathrm{fifty}$$

, P _o = (5-10) MPa, for deposits in the form of persistent rust and scale set $$\overline{x}=10-40$$

, P _o = (30-45) MPa. for cement with sand set $$\overline{x}=25-40$$

, P _o = (10-20) MPa.

The specified technical result is also achieved by the fact that the pulsation of the jet cavitating flow is ensured using a oscillating frequency generator, and the occurrence of resonance of the sediment layers is established to increase the concentration of contamination of the destroyed layers in the diverted flow, while the pulsation frequency of the jet cavitating flow is fixed, which further affects surface to be cleaned.

The invention is illustrated by drawings, where:

проникновения эрозии вглубь наслоений на очищаемой поверхности от относительного расстояния $$\overline{X}$$

от выхода кавитатора до очищаемой поверхности;figure 1 presents a graph of the relative intensity rate $$\overline{{\nu }_{\mathrm{uh}}}$$

penetration of erosion deep into the layers on the surface being cleaned from a relative distance $$\overline{X}$$

from the exit of the cavitator to the surface being cleaned;

до поверхности воздействия струйного потока;figure 2 presents the relative dependence of the intensity of the zone of expansion of the erosion of the layering Se from the relative distance $$\overline{X}$$

to the surface of the jet stream;

figure 3 presents the relative dependence of the intensity of the mass erosive removal of Ge material from the cleaning surface from the relative distance to the surface of the impact of the jet stream;

, Sэ, Gэ от относительного расстояния $$\overline{X}$$

(соответственно кривые 1, 2, 3) при определении оптимальных параметров и выборе зоны максимального эрозионного воздействия суперкавитационного струйного потока, истекающего из возбудителя кавитации, для получения максимального эффекта суперкавитации;figure 4 presents a graph of combined dependencies $$\overline{{\nu }_{\mathrm{uh}}}$$

, Se, Ge from the relative distance $$\overline{X}$$

(respectively, curves 1, 2, 3) when determining the optimal parameters and choosing the zone of maximum erosion from the supercavitation jet stream flowing out of the cavitation pathogen to obtain the maximum effect of supercavitation;

и переменном противодавлении от 0 до 1,8 МПа с эпюрой скорости потока.figure 5 presents a schematic drawing of the effects of jet cavitation flow on the surface to be cleaned at constant values of the input pressure parameters P ₀ , the relative distance to the surface of the sample, $$\overline{X}$$

and variable backpressure from 0 to 1.8 MPa with a flow velocity plot.

The proposed method is based on the principle of choosing the optimal parameters of a supercavitational jet fluid outflow from a cavitation pathogen with an effect on the effectiveness of erosion, which determines the productivity and quality of the surface cleaning process from layering.

The effectiveness of the erosive effect of a flooded supercavitation jet depends on the applied pressure to the hole of the cavitation pathogen (cavitator), back pressure in the flooded cavity, the distance from the nozzle exit, and also the design of the cavitator elements.

The proposed method is as follows.

, P_o и Pc, где $$\overline{x}$$

- относительное расстояние от выхода кавитатора до очищаемой поверхности, P_o - динамическое давление на выходе кавитатора, Pc - статическое давление в затопленной полости, при этом $$\overline{x}=\raisebox{1ex}{$l$}\!\left/ \!\raisebox{-1ex}{$d_0$}\right.$$

, где l - расстояние от выхода кавитатора до очищаемой поверхности, d_o - диаметр проходного рабочего сечения кавитатора, причем значения параметров $$\overline{x}$$

и P_o задают в пределах:The surface being cleaned is exposed to a liquid working medium in a state of cavitating vibrating flow created by the cavitator. In this case, the impact on various types of layers of deposits, contaminants and growths on the surface to be cleaned is carried out taking into account the types of deposits, pollution and growths on the surface to be cleaned by setting appropriate values of the physical parameters of the working medium, the cavitator geometry and its position relative to the surface being cleaned: $$\overline{x}$$

, P _o and Pc, where $$\overline{x}$$

is the relative distance from the exit of the cavitator to the surface being cleaned, P _o is the dynamic pressure at the exit of the cavitator, Pc is the static pressure in the flooded cavity, while $$\overline{x}=\raisebox{1ex}{$\mathrm{<figure-callout\; id="0"\; label="l\; d"\; filenames="00000047.png,00000048.png"\; state="\{\{state\}\}">l\; </figure-callout>}$}\!\left/ \!\raisebox{-1ex}{$d_{}$}\right.$$

where l is the distance from the exit of the cavitator to the surface being cleaned, d _o is the diameter of the passage through the working section of the cavitator, and the parameter values $$\overline{x}$$

and P _{o are} set within:

, P_o=(5-45) МПа, $$\overline{x}=5-\mathrm{fifty}$$

, P _o = (5-45) MPa,

с обеспечением пульсации струйного кавитирующего потока с переменной частотой и достижением резонанса слоев отложений.and the static pressure Pc in the flooded cavity is set in accordance with the condition $$P_c=\mathrm{0,075}{P}_o\exp (-0.4\sqrt{\overline{x})}$$

providing pulsation of the jet cavitating flow with a variable frequency and achieving resonance of the layers of the deposits.

When implementing the proposed method, the phenomenon of resonance of the layers of deposits on the surface being cleaned is used. The resonance frequency depends on the physical properties of the material of the deposits and the thickness of the layer, which is forced into vibration by a pulsating jet stream.

In this case, the oscillating frequency generator is used and the occurrence of the resonance of the sediment layers is established to increase the concentration of contaminants of the destroyed layers in the exhaust stream, the resonant frequency is fixed, at which they further influence the surface being cleaned.

For the theoretical justification of the proposed method, the following notation is used:

P - cleaning performance, m ² / s;

;ν _n is the velocity of the supercavitation jet along the surface being cleaned, m / s,

;

ν _e - the rate of intensity of penetration of erosion deep into the layers on the surface being cleaned, m / s;

;Sn is the width of the strip removal of deposits, m,

;

S _e - the intensity of the zone of expansion of erosion of layers, m;

;Gm - the mass of the deposited material of the layers, kg,

;

Ge - the intensity of the mass erosive removal of material from the cleaning surface, kg / s;

;K - experienced constant

;

I _er - the intensity of the erosive effects of the jet supercavitation flow.

With sufficient accuracy for practice, the productivity of erosion destruction and removal of deposits by the action of a supercavitational fluid flow on the surface of the jet spreading, taking into account the intensity of the parameters of erosion, can be determined from the expression:

In turn, the intensity of the erosive effect of the jet supercavitation stream unambiguously depends on the strength characteristics of the layering material and its thickness, as well as the dynamic and cavitation parameters of the jet supercavitation stream. The functional dependence of the intensity of the erosive effect of the jet supercavitation flow on the surface of the layering material on various parameters of the exposure process can be represented in general form:

- относительное расстояние l от выхода кавитатора до поверхности воздействия струйного суперкавитационного потока $$\raisebox{1ex}{$l$}\!\left/ \!\raisebox{-1ex}{$d_0$}\right.$$

.where M is the erosion resistance of the layering material to supercavitation destruction, taking into account the adhesion characteristics of the layers; δ is the thickness of the layering material, m; d ₀ is the diameter of the passage through the working section of the cavitator, m; P ₀ - dynamic pressure at the exit of the cavitator, MPa; Pc — static pressure in the flooded cavity, MPa; $$\overline{X}$$

- the relative distance l from the exit of the cavitator to the surface of the action of the jet supercavitation flow $$\raisebox{1ex}{$\mathrm{<figure-callout\; id="0"\; label="l\; d"\; filenames="00000047.png,00000048.png"\; state="\{\{state\}\}">l\; </figure-callout>}$}\!\left/ \!\raisebox{-1ex}{$d_{}$}\right.$$

.

All factors included in dependence (2) can be divided into two groups.

The first group includes those that are variables, but unregulated when choosing the parameters of the erosion process.

This group includes: erosion resistance of the surface coating material cavitation destruction, the thickness of the layering material.

The second group of factors that can be regulated includes the diameter of the working passage of the cavitation-cavitator pathogen, the dynamic pressure at the cavitator outlet, the static pressure in the flooded cavity, the distance from the cavitator exit to the surface of the supercavitation jet impact, the time of the supercavitation jet impact on the surface of the layering material.

от выхода кавитатора до очищаемой поверхности и статического давления в затопленной полости Pc.In the proposed method, the cleaning process is determined by the choice of adjustable parameters, namely the dynamic pressure at the outlet of the cavitator P ₀ , the relative distance $$\overline{X}$$

from the exit of the cavitator to the surface being cleaned and the static pressure in the flooded cavity Pc.

After selecting the operating parameters of the hydrodynamic high-pressure installation, they go on to determine and select the optimal static pressure in the flooded cavity Pc, calculated by the formula:

, то при воздействии на поверхность из какого-либо хрупкого, но прочного материала можно увидеть кратеры эрозионного разрушения (фиг.5).If we change the static pressure in the flooded region of the outflow of the supercavitation jet stream from 0 to 2 MPa with a constant inlet pressure into the cavitator P ₀ = 20 MPa and the relative distance $$\overline{X}=\mathrm{fifty}$$

, then when exposed to a surface from any fragile, but durable material, erosion destruction craters can be seen (Fig. 5).

As can be seen from figure 5, with an increase in P _c from 0 to 1.2 MPa, the erosion zone of the destruction of the material increases, from 1.2 to 1.5 MPf it is maximum, and from 1.5 to 2 MPa it decreases.

To obtain the maximum or necessary productivity of the cleaning process and confirm the legitimacy of the selected initial parameters, it is necessary to perform the appropriate technological calculations.

If, for example, the strength characteristics of the layers (which must be removed from the surface of the material) are close to the strength of cement grade 500, then as an example, you can use the formulas obtained by the author.

или по представленному графику относительной зависимости $${\overline{\nu }}_{э}={\nu }_{э}/\nu {э}_{MAX}$$

примера одного значения P_0, представленного на фиг.1:1. The penetration rate of erosion deep into the cleaned surface νe, m / s, determined by the formula (4) by substituting the corresponding values of P ₀ and $$\overline{X}$$

or according to the presented graph of relative dependence $${\overline{\nu }}_{\mathrm{uh}}={\nu }_{\mathrm{uh}}/\nu {\mathrm{uh}}_{MAX}$$

an example of one value of P ₀ presented in figure 1:

where C ₁ = -0.0136exp (-0.17 P ₀ ); C ₂ = -0,044 (0,064P ₀ -1);

To ¹ is a constant coefficient.

From the dependency analysis depicted in FIG. 1, it follows that the process of the rate of penetration of erosion deep into the layers can be divided in time into three periods.

величина $$\overline{{\nu }_{э}}$$

резко снижается на 50%, а затем с ростом величины $$\overline{X}$$

увеличивается на 20% и постепенно падает. Это объясняется тем, что при близком расстоянии от среза кавитатора до очищаемой поверхности на обрастания воздействуют как динамическим максимальным струйным давлением, так и кавитационным эрозионным эффектом. С увеличением $$\overline{X}$$

динамический эффект резко уменьшается, а кавитационный эффект увеличивается за счет расширения зоны кавитационной каверны G_э. (фиг.2).In the first period, calculated in a few seconds, with an increase $$\overline{X}$$

value $$\overline{{\nu }_{\mathrm{uh}}}$$

decreases sharply by 50%, and then with increasing value $$\overline{X}$$

increases by 20% and gradually decreases. This is explained by the fact that at a close distance from the cutter of the cavitator to the surface being cleaned, fouling is affected by both dynamic maximum jet pressure and cavitation erosion effect. With increase $$\overline{X}$$

the dynamic effect decreases sharply, and the cavitation effect increases due to the expansion of the zone of the cavitation cavity G _e . (figure 2).

, полученных по экспериментальным данным для кавитаторов с различными диаметрами проходного сечения, позволяет заключить, что увеличение диаметра сопровождается ростом νэ.Dependency mapping $$\overline{\nu }\mathrm{uh}=f\left(\overline{X}\right)$$

obtained from experimental data for cavitators with different diameters of the passage section allows us to conclude that an increase in diameter is accompanied by an increase in νe.

или по представленному графику относительной зависимости $$\overline{S}э=Sэ/S{э}_{MAX}$$

для примера одного значения P₀, представленного на фиг.2:2. The intensity of the zone of expansion of erosion of layers S _e is determined by the formula by substituting the corresponding values of P ₀ and $$\overline{X}$$

or according to the presented graph of relative dependence $$\overline{S}\mathrm{uh}=S\mathrm{uh}/S{\mathrm{uh}}_{MAX}$$

for example, one value of P ₀ presented in figure 2:

Where

C ₁ = -7.510 ^-4 exp (-0.046P ₀ ), C ₂ = 0.3P ₀ +4.5.

ширина очага эрозии изменяется по кривой с максимумом. С увеличением P_o положение максимума может смещаться в сторону увеличения $$\overline{X}$$

.The graph analysis in FIG. 2 shows that with increasing $$\overline{X}$$

the width of the erosion focus changes along a curve with a maximum. With an increase in P _{o, the} position of the maximum can shift upwards $$\overline{X}$$

.

или по представленному графику относительной зависимости $$\overline{Gэ}=Gэ/G{э}_{MAX}$$

для примера одного значения P₀, представленного на фиг.33. The intensity of mass erosive removal of material from the cleaning surface G _e can be calculated by the formula by substituting the corresponding values of P ₀ and $$\overline{X}$$

or according to the presented graph of relative dependence $$\overline{G\mathrm{uh}}=G\mathrm{uh}/G{\mathrm{uh}}_{MAX}$$

for example, one value of P ₀ presented in figure 3

A = 190.35P ₀ ² + 7.9P ₀ ; B = 1.21P ₀ +0.009.

можно (как и на фиг. 1) разделить по времени на три периода. В первом, исчисляемом несколькими секундами, с увеличением $$\overline{X}$$

величина $$\overline{G_{э}}$$

резко снижается на 40%, а затем с ростом величины $$\overline{X}$$

увеличивается на 20% и затем постепенно падает.From the dependency analysis depicted in FIG. 3, it follows that the entire process of the intensity of mass erosive removal of material from the cleaning surface $$\overline{G_{\mathrm{uh}}}$$

can (as in Fig. 1) be divided in time into three periods. In the first, calculated in a few seconds, with an increase $$\overline{X}$$

value $$\overline{G_{\mathrm{uh}}}$$

decreases sharply by 40%, and then with increasing value $$\overline{X}$$

increases by 20% and then gradually decreases.

прямо пропорционально зависит от величины $$\overline{{\nu }_{э}}$$

.This is because the quantity $$\overline{G_{\mathrm{uh}}}$$

directly proportional to $$\overline{{\nu }_{\mathrm{uh}}}$$

.

For clarity, the choice of the optimal operating parameters of the jet supercavitational fluid flow results of experimental studies, presented in Fig.1-3, are summarized in a combined graph in Fig. 4, in which the numbers indicate:

,1 - relative intensity of the zone of expansion of erosion of layers $$\overline{S}\mathrm{uh}=S\mathrm{uh}/S{\mathrm{uh}}_{MAX}$$

,

,2 - the relative rate of intensity of penetration of erosion deep into the layers on the surface to be cleaned $${\overline{\nu }}_{\mathrm{uh}}={\nu }_{\mathrm{uh}}/\nu {\mathrm{uh}}_{MAX}$$

,

от относительного расстояния $$\overline{X}=l/d_o$$

от среза кавитатора до поверхности растекания суперкавитационной струи.3 - the relative intensity of the mass erosive removal of material from the cleaning surface $$\overline{G\mathrm{uh}}=G\mathrm{uh}/G{\mathrm{uh}}_{MAX}$$

from relative distance $$\overline{X}=l/d_o$$

from a cut of a cavitator to a spreading surface of a supercavitation jet.

(заштрихованный участок).From FIG. 4 it follows that the optimal distance for the maximum zone of supererosion from the surface to the cut of the cavitator is in the range $$\overline{X}=\left(40-60\right)$$

(shaded area).

, как показано на фиг.4.To obtain the maximum effect of supercavitation when working with a high-pressure pump unit, it is necessary to select and calculate, according to the above formulas, such operating parameters of the supercavitation jet stream flowing from the cavitation pathogen so that all of them are in the zone of maximum erosion from the super cavitation jet stream flowing from the cavitation pathogen, for example, in zone $$\overline{X}=\left(40-60\right)$$

as shown in FIG.

Experimental studies have shown that by changing the parameters of cavitation, it is possible to obtain different intensities of erosive destruction of the material.

This provides an effective cleaning of surfaces from deposits with different resistance to cavitation and erosion, and the restoration of the working capacity and flow rates of water and producing oil and gas wells.

Substituting the found values into formula (1) and formula (2), it is possible to determine the optimal cleaning performance with sufficient accuracy for practice, subject to the selected parameter values.

An example of the technical implementation of the proposed method is illustrated in the figure in Fig.5.

The high-pressure fluid flow 1 coming from the high-pressure pump (not shown in the diagram) passes through the oscillating frequency generator 2, which is controlled by the control unit 3, and enters the cavitator 4. In this case, the cavitator 4 is introduced into the impact zone (well or pipe) using appropriate technical means (not shown in FIG. 5).

In cavitator 4 (see, for example, cavitator design according to RF patent No. 2315848), cavitation is excited, due to which gas-vapor bubbles are released from the fluid flow, which, when flowing out into the surrounding fluid flow, form a cavity with toroidal sections along its length. The flow rate initially increases, but due to a part of collapsing gas-vapor bubbles it is sharply inhibited and due to their collapse it further increases. Dynamic ripple of the flow occurs with a change in frequency and amplitude. When a jet pulsating flow spreads over a surface with deposits, this pulsation exerts a variable hydrodynamic pressure on the deposits.

If the pulsation frequency in the spreading jet cavitation stream reaches the resonant frequency of the sediment layers, then they are destroyed and carried away by the diverted stream.

The oscillating frequency generator 2, controlled by block 3, acts on the fluid flow, increasing or decreasing the frequency of pulsation of the hydrodynamic pressure in the jet stream until a resonance of the sediment layers occurs, which is controlled by increasing the concentration of contaminants leaving the well and pipeline. Monitoring can be carried out visually by the operator (diver) or automatically (using optical sensors for contamination of the stream). In this case, the block 3 generates a control signal to the generator 4 to fix the frequency at which the pulsation of the fluid flow entering the cavitator 4 is carried out, which forms a jet cavitating flow 5.

When the back pressure Pk changes into the surrounding fluid stream, the control unit 3 of the oscillator of the oscillating frequency 2 is reconfigured to a new value when the resonance of the sediment layers is reached.

With increasing backpressure in the surrounding fluid stream to 1.2 MPa, there is an increase in the destructive capacity of cavitation in the jet stream (see the increase in the size of erosion craters 6 in FIG. 5). This is because backpressure affects the effectiveness of the explosive action of gas-vapor bubbles. A further increase in the back pressure Pк (more than 1.2 MPa) in the surrounding fluid flow reduces the efficiency due to the “crushing” of cavitation.

Based on the experiments with various types of deposits, the optimal values of the cleaning parameters were obtained, which must be maintained to ensure effective cleaning for specific types of deposits, pollution and growths, presented in the table.

Thus, the proposed method for cleaning and restoring the health of wells and pipelines allows you to configure the parameters of the impact on the treated surface with a jet cavitating vibrating flow, to achieve the maximum degree of impact, and thereby increase the efficiency of cleaning and restoring the health of wells and pipelines.

The tests showed a high efficiency of cleaning wells and pipelines, since it adjusts the physical parameters of the hydro-cavitation effects on specific types of layered deposits, contaminants and growths, taking into account the resonance properties of these layers on internal surfaces.

The proposed method meets the conditions of novelty and industrial applicability and can be repeatedly reproduced.

To implement the proposed method, standard equipment is used to create high-pressure jets of liquid, a cavitator with certain design requirements, means to ensure the introduction of the cavitator into the pipeline or well at a certain depth, and process control means, for example, a oscillating frequency generator (“sweep generator”) , control unit and sensors, allowing to monitor the process.

Claims (9)

1. The method of cleaning and restoring the health of wells and pipelines, based on the impact on the surface to be cleaned with a liquid working medium in a state of cavitating vibrating flow created by the cavitator, characterized in that the effect on various types of layers of deposits, dirt and growths on the surface being cleaned is carried out with taking into account the types of deposits, pollution and growths on the surface to be cleaned by setting the appropriate values of the physical parameters of the working environment, geo etrii cavitator and its position relative to the surface to be cleaned: $$\overline{x}$$

, P _o and Pc, where $$\overline{x}$$

is the relative distance from the exit of the cavitator to the surface being cleaned, P _o is the dynamic pressure at the exit of the cavitator, Pc is the static pressure in the flooded cavity, while $$\overline{x}=\raisebox{1ex}{$l$}\!\left/ \!\raisebox{-1ex}{$d_0$}\right.$$

where l is the distance from the exit of the cavitator to the surface being cleaned, d _o is the diameter of the passage through the working section of the cavitator, and the parameter values $$\overline{x}$$

and P _{o are} set within:
$$\overline{x}=5-\mathrm{fifty}$$

, P _o = (5-45) MPa,
and the static pressure Pc in the flooded cavity is set in accordance with the condition P _c = 0,075 $$P_o\exp (-0.4\sqrt{\overline{x})}$$

providing pulsation of the jet cavitating flow with a variable frequency and achieving resonance of the layers of the deposits. 2. The method according to claim 1, characterized in that for deposits in the form of loose rust and scale set $$\overline{x}=40-\mathrm{fifty}$$

, P _o = (12-20) MPa. 3. The method according to claim 1, characterized in that for the growths in the form of limestone set $$\overline{x}=10-40$$

, P _o = (5-15) MPa. 4. The method according to claim 1, characterized in that for clay layers $$\overline{x}=5-10$$

, P _o = (10-15) MPa. 5. The method according to claim 1, characterized in that for sandy layers set $$\overline{x}=40-\mathrm{fifty}$$

, P _o = (5-10) MPa. 6. The method according to claim 1, characterized in that for deposits in the form of persistent rust and scale set $$\overline{x}=10-40$$

, P _o = (30-45) MPa. 7. The method according to claim 1, characterized in that for cement with sand set $$\overline{x}=25-40$$

, P _o = (10-20) MPa. 8. The method according to claim 1, characterized in that the pulsation of the jet cavitating flow is provided using a oscillating frequency generator. 9. The method according to claim 1, characterized in that the occurrence of resonance of the layers of the deposits is established to increase the concentration of contaminants of the destroyed layers in the exhaust stream, while the pulsation frequency of the jet cavitating stream is fixed, which further affects the surface being cleaned.

Images