EA028724B1 - Device for hydrodynamic cavitational well treatment - Google Patents

Abstract

The invention relates to the field of downhole technologies and is intended for complex treatment of productive layers of production wells by hydrodynamic cavitation wave action on the near-well zone of oil and gas reservoirs. Summary of the invention: the device comprises a hollow housing connected to a pipeline in which a hydraulically interconnected a fluid flow pre-swirling chamber, a swirl chamber and a hydrodynamic pulsator-cavitator, including a confuser, a resonance chamber and a diffuser, are placed sequentially top-down. In the flow pre-swirling chamber, there are arranged the flow direction and separation mechanism and the flow shutoff mechanism, including tangential channels for supplying liquid to cavity of the chamber, arranged along the lateral edges of the chamber, an impeller with inclined blades installed in the chamber with the possibility of axial rotation under the action of pressure of liquid jets, exiting from tangential channels, spherical rolling bodies located along the circumference of the impeller in the holes made therein and supported by a circular groove of the common rolling contact bearing. In the circular groove of the common rolling contact bearing, there are made inlet holes of the tangential channels of the common rolling contact bearing, hydraulically coupled with to swirling chamber located below. In the swirling chamber and confuser, coaxially with them, a reflector with a conical spike and the point directed towards the resonance chamber, is installed. The technical result is increase of the cavitation degree and increase of reliability of the structure.

Description

The invention relates to the field of downhole technologies and is intended for the integrated treatment of productive reservoirs of production wells by hydrodynamic cavitation wave action on the borehole zone of oil and gas reservoirs.

Known borehole sonar generator [1], comprising a housing, a vortex chamber with tangential channels, a chamber for preliminary swirling of the flow with tangential channels. The tangential channels of the vortex chamber and the preliminary flow swirling chamber have the same rotational direction.

Known hydrocavitation device [2] containing a flow channel and a profile. The latter is formed by coaxially located and sequentially conjugated to each other by the input confuser, cylindrical and output parts. The cylindrical part is made in the form of a resonance chamber, and the output part is in the form of a stop. The diameter of the chamber is larger than the diameter of the outlet of the confuser and the inlet of the outlet.

The disadvantage of such devices is the low level of amplitudes of the wave action.

The closest in technical essence is a device for hydrodynamic effects on the walls of the well [3], taken as a prototype. The device includes a hollow body connected to the pipeline, inside of which there is a hydrodynamic pulsator-cavitator, including a diffuser, a flow direction and separation mechanism, and a fluid flow interruption mechanism made in the form of rolling elements distributed by means of an impeller and resting on a common rolling support.

A limitation of the device is the insufficient degree of cavitation, especially in deep wells (more than 2000 m) [4, p. 128, 130]. In such cases, the cavitation zone is located within the internal cavity of the device, where the cavitation bubbles collapse, leading to the destruction of the structural elements of the generator [5, p. 50] and a decrease in its reliability. This effect is complicated by the fact that the cavitation mechanism is located before the mechanism for interrupting the flow of the working fluid. To ensure the operability of the device adopted as a prototype, a flow of working fluid of several tens of liters per second is required, which makes it impossible to use it when treating wells with reagents (in particular, during acid treatments) for technical and economic reasons. With the stated ratio of 0.98 the diameter of the ball of the cavitation mechanism to the diameter of the passage section of the housing, the performance of such a pulsator will be very sensitive to the presence of mechanical impurities in the working fluid.

The problem solved by this invention is to increase the degree of cavitation (the number of cavitation bubbles outside the device) and increase the reliability of the design.

The problem is solved due to the fact that in the device for hydrodynamic cavitation treatment of the well, containing a hollow body connected to the pipeline, inside which there is a hydrodynamic pulsator-cavitator, including a diffuser, a mechanism for directing and separating the flow and a mechanism for interrupting the fluid flow, made in the form of bodies rolling distributed using an impeller and resting on a common rolling support, according to the invention, the hydrodynamic pulsator-cavitator includes a confuser and a resonant a camera; the flow direction and separation mechanism and the flow interruption mechanism are arranged in a chamber for preliminary swirling of the fluid flow, along the lateral edges of which tangential channels are made for supplying fluid to the chamber cavity, in which an impeller with inclined blades is mounted around the circumference with the possibility of axial rotation of the fluid jets. which in the holes are the ball rolling bodies supported on a circular groove with the inlet holes of the tangential channels of the common support hydraulically connected with the swirl chamber and confuser located below and connected in series, in which a reflector with a conical spire is installed coaxially with them, with its tip directed towards the resonance chamber.

In addition, the resonance chamber may have an elliptical cross-section with a preferred axis ratio of 1.45-1.75.

In addition, the impeller blades can have the same inclination with the axial inclination of the tangential channels of the common rolling bearings.

In a preferred embodiment, the ball rolling bodies can be installed in the chamber for preliminary swirling of the flow, providing a gap d between them and the circular groove during their movement, equal to 0.05-0.1 of the diameter of the ball rolling body.

In addition, inclined slots can be made on the part of the reflector located in the confuser.

A device for hydrodynamic cavitation treatment of a well is illustrated by the following drawings: in FIG. 1 shows a vertical section through a device; in FIG. 2 is a view A in FIG. one; in FIG. 3 section BB in FIG. one; in FIG. 4 is a section bb in FIG. one; in FIG. 5 is an isometric view of the general rolling support.

The device comprises a hollow body 1 (Fig. 1), attached to the pipeline (not shown in Fig.), Inside of which a fluid flow pre-swirling chamber 2, hydraulically connected to each other, is arranged successively from top to bottom, in which the flow direction and separation mechanism and the interrupt mechanism are arranged flow, swirl chamber 3 and hydrodynamic pulse - 1 028724 tor cavitator 4, including confuser 5, resonance chamber 6 and diffuser 7. The mechanism of direction and separation of the flow and the mechanism for interrupting the flow of the working fluid includes tangential channels 8 (Fig. 3) for supplying a working fluid into the cavity of the chamber 2, made along its lateral edges, an impeller 9 with inclined blades 10 (Fig. 1, 2), around the circumference of which in the holes there are ball rolling elements 11 with a support on a circular groove-treadmill 12 with the provision of overlapping by the ball bodies during their movement of the inlet holes 13 of the tangential channels 14 of the common rolling support 15 made in the grooves. The ball rolling bodies 11 are arranged with a gap δ equal to 0.05-0.1 of the diameter of the ball body rolling between a tax circular groove - treadmill 16, made in the upper part of the chamber 2 (Fig. 2). The impeller 9 is installed in the chamber 2 with the possibility of axial rotation, provided by the pressure of the jets of the working fluid on the inclined blades 10. The tangential channels 14 provide a hydraulic connection between the preliminary swirling chamber of the fluid flow 2 and the swirl chamber 3 and have the same axial inclination with the inclination of the blades 10 of the impeller 9. In the swirl chamber 3 and the confuser 5, a reflector 17 is installed coaxially with them with a conical spire 18, the tip directed towards the resonant chamber 6, in a preferred embodiment having in cross section an ellipse shape with a small axis α (Fig. 4). The reflector 17 with the upper part is installed in the chamber for preliminary twisting of the fluid flow by means of a nut 19, while inclined slots 20 are made on the part of the reflector 17 located in the confuser 5.

A device for hydrodynamic cavitation treatment of a well works as follows.

The working fluid under a given pressure through the pipeline through the tangential channels 8 is fed into the preliminary twisting chamber 2 and, getting on the inclined blades 10 of the impeller 9, drives it in rotation together with the ball rolling elements 11, which sequentially block the inlet openings 13 of the common rolling bearings 15 and thereby thereby creating pressure pulsations of the working fluid flowing through tangential channels 14 to the swirl chamber 3. Due to the inclination of the blades 10 of the impeller 9, a lifting force is created, which leads to the formation of axial the gap δ between the ball rolling elements 11 and the lower groove of the treadmill 12 and thereby prevents the occurrence of water hammer and wear of the treadmill in the area of the inlet openings 13. To prevent loss of operability of the device when the impeller is jammed, the ball body 11 covers no more than 80% of the passage cross sections of the inlets 13. At inclined grooves 20 of the reflector 17, flow turbulences occur that increase the degree of cavitation. When the working fluid enters confuser 5, its flow accelerates, and in the narrowing region, continuity breaks with the formation of vapor-gas cavitation bubbles transferred by the flow to the resonance chamber 6. In the resonance chamber 6, pressure pulsations are amplified, the effect of which improves due to the elliptical shape of its transverse sections. Gas-vapor bubbles through the diffuser 7 are carried out into the borehole space, where, falling into the high-pressure region, they collapse, creating pressure pulses that act on the borehole walls.

We studied the behavior of the cavitator pulsator at different ratios of the axes of the elliptical section of the resonance chamber 6 by studying pressure pulsations (working fluid - water) at the outlet of the device at a distance of 50 mm. The research results showed that the ratio of the axes equal to 1.45-1.75 can be considered optimal.

The implementation of the pilot field test program of the inventive device took place at the deposits of the Republic of Belarus in the period 2013-2014. Work on stimulation of the inflow was carried out at five producing wells, the success rate was 80%, and the productivity coefficient increased from 30 to 60%. The greatest effect was achieved in low-productivity wells (below 1 m ³ / (day-MPa). The dependence of the increase in productivity coefficient (in%) on the energy state of the deposit is direct, which is generally characteristic of all geological and technical measures for intensification. The device is recommended for industrial implementation.

Information sources:

1) KI 2186961, IPC Е21В 43/25, publ. 09/09/10

2) KI 2123957, IPC В63В 59/08, В08В 3/02, publ. 1998.12.27.

3) KI 2224090, IPC Е21В 43/00, publ. 2004.02.20.

4) Ibragimov L.Kh., Mishchenko I.T., Cheloyants D.K. Intensification of oil production. - M .: Science. 2000, p. 414

5) Shamov N.A., Lyagov A.V., Zinatullina E.Ya., Aseev E.G., Bubelov A.V. Technology and technical means of improving the hydrodynamic connection of a well with a formation // Oil and Gas Business. - 2006, v. 4, No. 1, p. 47-57.

Claims (5)

CLAIM 1. A device for hydrodynamic cavitation treatment of a well, comprising a hollow body attached to the pipeline, inside of which there is a hydrodynamic pulsator - 2 028724 cavitator, including a diffuser, a flow direction and separation mechanism, and a fluid flow interruption mechanism made in the form of rolling bodies distributed by impellers and resting on a common rolling support, characterized in that the hydrodynamic pulsator-cavitator includes a confuser and a resonant chamber; the flow direction and separation mechanism and the flow interruption mechanism are arranged in a chamber for preliminary swirling of the fluid flow, along the lateral edges of which tangential channels are made for supplying fluid to the chamber cavity, in which an impeller with inclined blades is mounted around the circumference with the possibility of axial rotation of the fluid jets. which in the holes are the ball rolling bodies supported on a circular groove with the inlet holes of the tangential channels of the common support hydraulically connected with the swirl chamber and confuser located below and connected in series, in which a reflector with a conical spire is installed coaxially with them, with its tip directed towards the resonance chamber. 2. The device according to claim 1, characterized in that the resonance chamber has an elliptical cross-section with an axis ratio of 1.45-1.75. 3. The device according to claim 1, characterized in that the impeller blades have the same inclination with the axial inclination of the tangential channels of the common rolling bearings. 4. The device according to claim 1, characterized in that the ball rolling bodies are installed in the pre-swirling chamber of the flow with a gap δ between them and the circular groove during their movement equal to 0.05-0.1 of the diameter of the ball rolling body. 5. The device according to claim 1, characterized in that the inclined grooves are made on the part of the reflector located in the confuser.