RU2506413C1 - Well strainer cleanout device - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is referred to an oil-and-gas industry. The cleanout device makes hydrowave impact by means of hydropulsator on a column of washing liquid inside the well strainer; the device contains computer, hydropulsator, washing liquid return pipeline connected to gap between casing string and tubing string. Hydropulsator is installed at washing liquid feed pipeline inside tubing string; it can alternate ripple frequency for automatic tuning of resonance frequency. Frequency sensors and oscillation amplitude sensors connected to computer by electric coupling at washing liquid feed pipeline. Hydropulsator can vary amplitude of oscillations by use of bypass channel with tap parallel to hydropulsator.

EFFECT: increasing cleanout efficiency and speed.

2 cl, 5 dwg

Description

The invention relates to the oil and gas industry, is specifically intended for cleaning downhole filters.

It is known that well filters become clogged during operation (mudding occurs) and the well flow rate decreases several times.

Methods for cleaning downhole filters can be divided into two groups:

- purification of asphalt-resinous and paraffin hydrate deposits (soluble),

- purification of solid mechanical deposits (sand, clay, dolomite and other insoluble impurities).

In the first case, heat or solvents are used, and in the second, mechanical cleaning or wave (acoustic or hydraulic) action.

The known method and device for cleaning the downhole filter according to the patent of the Russian Federation for the invention No. 2332560 IPC ЕВВ 43/00, publ. August 27, 2008

The downhole filter with the cleaning function is made in the form of a pipe with nipple threaded sections, one of which has a coupling and with holes on the side of the pipe. The filter element is installed concentrically to the pipe. The filter element is made in the form of two electrodes isolated from each other by means of a grid of non-conductive material. The electrodes are made in the form of a metal mesh and have the ability to connect to a source of electricity. The energy source is placed on the surface or made autonomous, for example, in the form of a battery of batteries or an electric generator and installed inside the downhole filter. The technical result is an increase in well production due to periodic cleaning of the filter element.

The disadvantages of this technical solution: the ability to clean only from tar and paraffin deposits and the need to supply electricity to a great depth.

A known method and device for cleaning a downhole filter according to the patent of the Russian Federation No. 2382178 IPC E21D 37.08 publ. 09/27/2009

A device for cleaning a downhole filter includes an oscillator installed in the housing, and means for delivering an oscillator to the bottom of the well and supplying electricity. A geophysical cable is used as a means of supplying electricity. The means of delivery of the oscillation generator contains an electric motor with a hydraulic propulsion. The electric motor and oscillation generator are installed in a sealed enclosure. The hydraulic propeller is made with two propellers connected to the electric motor through a transmission mechanism to allow rotation in opposite directions. The technical result is the provision of cleaning the downhole filter and delivery of the cleaning device to the horizontal section of the well, preventing twisting of the geophysical cable due to rotation of the device.

Disadvantages: a complex and expensive delivery device, the presence of a multi-kilometer geophysical cable, the length of the process of cleaning downhole filters.

A known method and device for cleaning a downhole filter (self-cleaning downhole filter) according to the patent of the Russian Federation for invention No. 2338871, IPC ЕВВ 49/08, publ. 01/09/2007

This invention can be used in gas production and filtering water from sand. The self-cleaning well filter is made in the form of a pipe with nipple threaded sections, one of which has a coupling, and with holes on the side surface of the pipe, the filter element concentrically mounted on it. An insulated winding is installed in the filter element, which can be connected to an autonomous energy source, for example, a battery of power elements or an electric generator installed inside the downhole filter. The technical result is to increase the flow rate of the well due to periodic cleaning of the filter.

The disadvantage is the need for periodic replacement of power elements installed inside the downhole filter due to clutter of its internal section.

A known method and device for vibroacoustic impact on the formation according to the patent of the Russian Federation No. 2129659, IPC EV 43/00, publ. 01/27/1999

The method consists in the wave action on the column of flushing fluid inside the downhole filter.

The device contains a ground power and control panel with a power rectifier. The high-frequency generator module comprises a frequency driver stage unit, a power amplifier unit, a load matching unit, and a signal modulation unit. The ground electrical connector is communicated through the power cable with the electrical connector of the downhole vibro-acoustic device. In the housing of the latter there is a vibro-acoustic emitter module. The device is additionally equipped with a safety unit, a control rectifier unit, a signal modulation control unit, a signal modulation indication unit, a resonance chamber module, formed by two ends overlapping the cavity of the downhole vibro-acoustic device and its body. The high-frequency generator module is located in the body of the downhole tool and is equipped with a frequency filter unit and a load matching control unit, the vibro-acoustic emitter module is equipped with at least two electro-acoustic transducers, the upper and middle electro-acoustic transducers being rigidly connected respectively to the upper and lower ends of the resonance chamber module with her outside. The device is implemented in the form of two small ground units and a downhole vibro-acoustic device. The use of the invention increases the efficiency of the device and its reliability in operation due to the use of a direct current device power supply and controlled matching of radiation with the well environment.

The disadvantages of the method and device are the low efficiency of the cleaning process and its duration. This is due to the fact that the source of the wave action is located deep inside the well, making it difficult to supply energy to it and control it. A special electronic device must be developed for control. Long-term cleaning of the downhole filter leads to a decrease in the time of operation of the well and a decrease in the total flow rate of oil (gas).

Objectives of creating a group of inventions: a significant improvement and acceleration of the downhole filter cleaning.

The solution of these problems was achieved in a device for cleaning a downhole filter with a microwave by means of a hydraulic pulsator controlled by a computer on a flushing fluid column located inside a well filter containing a computer, a hydraulic pulsator on a flushing fluid supply pipe and a flushing liquid return pipe connected to the gap between the casing and the casing Tubing, the fact that according to the invention the hydro-pulsator is installed on the pipeline supplying flushing fluid inside the tubing string and made with the possibility of changing the ripple frequency to automatically adjust the resonant frequency, after the pulsator, pulsation frequency and amplitude sensors connected via electrical connection to the computer are connected through the measuring pipe and tap. The pulsator can be made with the possibility of changing the amplitude of the oscillations using a bypass channel with a crane, made parallel to the hydraulic pulsator.

The invention is illustrated in figure 1 ... 5, where:

- figure 1 shows a diagram of a device,

- figure 2 shows a diagram of a cleaning system with amplitude control,

- figure 3 shows a diagram of the impact on the well filter with a standing wave,

- figure 4 shows the configuration of the standing wave to obtain the maximum effect,

- figure 5 shows the algorithm of the device.

The device for implementing the method (figure 1 ... 5) is designed to clean the downhole filter 1 installed on the tubing string 2 inside the casing 3 in the region of the oil reservoir 4 located in the soil 5. This device contains a tank 6 for storing the flushing fluid, to which a low pressure pipe 7 is connected, having a filter 8 on one side and a pump 9 with a drive 10 on the other. A flushing fluid supply pipe 11 is connected to the pump 9 output, and a controlled pulsator 12 with a drive 13 is installed at the other end. From the pulsator 12 through the valve 14 it is connected to the internal cavity 15 of the tubing string 2. Between the tubing string 2 and the casing 3, a gap 16 is formed. The cavity of the gap 16 communicates with the annular cavity 17 of the manifold 18. A flushing fluid return pipe 19 is connected to the manifold 18, the other end which is located above the capacity of 6 or inside it.

The process control system is made in the form of a computer 20 (system unit), to which a monitor 22, a keyboard 23, and a mouse-type manipulator 24 are connected by electrical connections 21.

The drive 13 and the drive 10 are electrically connected 21 to a computer 20.

After the pulsator 13 through the measuring pipe 25 and the valve 26 are connected sensors of the frequency and amplitude of the pulsations, respectively 27 and 28 and the pressure gauge 29.

The second embodiment of the device (figure 2) further comprises a bypass pipe 30, made parallel to the valve 14 with the valve 31 (figure 2).

In operation, the computer 20 is turned on, on which the corresponding software is pre-installed.

In addition, voltage is supplied to the actuator 10 of the pump 9 and the flushing fluid is supplied through the pipe 10 through the pulsator 12 and the valve 14 into the cavity 15 of the tubing 2 and then into the downhole filter 1, then through the gap 16 to the manifold 18 and then returned through the discharge pipe 19 in the tank 10. At the same time, the computer 20 supplies an alternating voltage to the actuator 13 for periodically opening and closing the pulsator 14. The pulsator 14 creates pressure pulsations in the cavity 15 and inside the downhole filter 1. As a result, solid particles from the outside of the downhole filter 1 and fall into the gap 18 and further into the container 6.

The computer 20 determines the speed of sound in the washing liquid, depending on its temperature (figure 5). Using data on the depth of the well and / or length of the well (for horizontal and deviated wells), the computer 20 calculates the calculated resonant frequency, which may differ from the real resonant frequency. The frequency sensor measures the real frequency of the pulsations and adjusts the operation of the pulsator to reduce the difference between these values. At the same time, the amplitude of the pulsations is measured, and if its increase occurs, then the frequency correction is continued in the same direction. When reaching the maximum amplitude of the ripple stop correction.

Significant efficiency is obtained in the case of the use of a standing wave (Fig.3.). The greatest cleaning efficiency is obtained if the wavelength is greater than twice the length of the downhole filter, and the antinode is in the middle of the filter (figure 4).

Standing wave - oscillations in distributed oscillatory systems with a characteristic arrangement of alternating maxima (antinodes) and minima (nodes) of the amplitude. In practice, such a wave occurs during reflections from obstacles and inhomogeneities as a result of the superposition of the reflected wave on the incident wave. In this case, the frequency, phase, and attenuation coefficient of the wave at the reflection site are extremely important.

A purely standing wave, strictly speaking, can exist only in the absence of losses in the medium and complete reflection of waves from the boundary. Usually, in addition to standing waves, traveling waves are also present in the medium, bringing energy to the places of its absorption or radiation.

In the case of harmonic oscillations in a one-dimensional medium, a standing wave is described by the formula:

u = u ₀ coskxcos (ωt-φ),

where u are the perturbations at the point x at time t, u ₀ is the amplitude of the standing wave, ω is the frequency, k is the wave vector, φ is the phase.

Standing waves are solutions to wave equations. They can be imagined as a superposition of waves propagating in opposite directions.

If there is a standing wave in the medium, there are points where the amplitude of oscillations is zero. These points are called nodes of a standing wave. Points at which the oscillations have a maximum amplitude are called antinodes. In these places, the force effect of the wave on the walls of the downhole filter is maximum.

 Mathematical description of standing waves

In the one-dimensional case, two waves of the same frequency, wavelength and amplitude, propagating in opposite directions (for example, towards each other), will interact, resulting in a standing wave. For example, a harmonious wave, propagating to the right, reaching the end of the string, produces a standing wave. The wave that is reflected from the end must have the same amplitude and frequency as the incident wave.

Consider the incident and reflected waves in the form:

y ₁ = y ₀ sin (kx-ωt)

y ₂ = y ₀ sin (kx-ωt)

Where:

- y ₀ is the wave amplitude,

- ω - cyclic (angular) frequency, measured in radians per second,

- k is the wave vector, measured in radians per meter, and is calculated as 2π divided by the wavelength λ,

- x and t are variables to indicate length and time.

Therefore, the resulting equation for the standing wave y will be in the form of the sum of y ₁ and y ₂ :

y = y ₀ sin (kx-ωt) + y ₀ sin (kx + ωt).

Using trigonometric relations, this equation can be rewritten in the form:

y = 2y ₀ cos (ωt) sin (kx).

If we consider the modes x = 0, λ / 23λ / 2, ... antimodes

x = λ / 4,3λ / 4,5λ / 4, ... then the distance between adjacent modes / antimodes will be equal to half the wavelength λ / 2.

Wave equation

In order to obtain standing waves as a result of solving a homogeneous differential wave equation (d'Alembert)

,

,

it is necessary to set its boundary conditions accordingly (for example, fix the ends of the string).

In the general case of an inhomogeneous differential equation

,

,

where f ₀ plays the role of “force”, with the help of which the displacement is carried out at a certain point in the string, a standing wave arises automatically.

Software for implementing the method is developed. The algorithm of the computer is shown in Fig.5.

Computer requirements: Pentium 4 or lower, Windovs-XP OS.

The application of the invention allowed:

- to increase the efficiency of cleaning the downhole filter due to the high power of resonant pulsations and the use of a standing wave,

- accelerate the cleaning of the downhole filter,

- fully automate the cleaning process,

- to ensure ease of use, since all equipment is located on the surface,

- to ensure maintainability of the equipment due to its placement above the surface of the earth,

- quickly establish mass production of equipment for cleaning well filters. Use mass-produced personal computers with virtually no modifications, apart from developing a management program.

Claims (2)

1. A device for cleaning a downhole filter with a microwave effect using a computer-controlled hydraulic pulsator for a flushing fluid column located inside a well filter containing a computer, a hydraulic pulsator on a flushing fluid supply pipe and a flushing fluid return pipe connected to a gap between the casing and tubing string, characterized the fact that the hydro-pulsator is installed on the pipeline supplying washing fluid inside the tubing string, is configured to change the frequency pulsations for automatic tuning of the resonant frequency, after the hydro-pulsator through the measuring pipe and tap connected sensors of frequency and amplitude, connected by electrical communication with the computer. 2. The device according to claim 1, characterized in that the pulsator is made with the possibility of changing the amplitude of the oscillations using a bypass channel with a crane made parallel to the hydraulic pulsator.

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