RU2686936C1 - Device for increasing oil recovery of well formations - Google Patents

Abstract

FIELD: oil industry.SUBSTANCE: invention relates to oil and gas industry and can be used for increasing oil recovery of well formations. Device comprises a cavitation-wave generator, which is lowered into the interval of productive formation perforation, connected to a lower end of the flushing pipes column through a multi-cycle circulating valve assembly, as well as wellhead sealing and lowering and lifting equipment, a container with working fluid and a pump unit for its injection into the flushing pipe string. According to the invention, the multi-cycle circulating valve assembly is made in the form of a tubular coupling body having in its upper part a blind hole located along its main longitudinal axis, equipped with at least one radial channel hydraulically connected to the annular space, wherein the top of the blind hole is equipped with a seat for the spring-loaded locking element located above it with the annular clearance, and the working fluid flow from the flushing pipe column to the cavitation-wave generator is performed by means of at least one circumferentially located in the body of the longitudinal through hole with the non-circular cross section.EFFECT: technical result consists in reduction of labour intensity and expenditure of time for performance of cavitation-wave treatment of bottomhole zone of productive formations of wells.1 cl, 4 dwg

Description

The invention relates to the field of oil and gas industry and is designed to solve problems of restoring the reservoir properties of productive layers of oil and gas wells and involving in the development of hard-to-recover and unprofitable hydrocarbon reserves, and can also be used to increase the injectivity of injection wells and decollate the filters and zones of hydrogeological wells.

Known devices for enhanced oil recovery wells, using for the processing of the bottomhole zone of the wellbore technology controlled cavitation wave process. All these devices, differing from each other in the design features of the cavitation-wave generators used in them, have a common drawback, which consists in the difficulty and impossibility of carrying out their accelerated descent on the column of flushing tubes due to the small cross section of the discharge (cavitation) channels of the jet apparatus (nozzle), creating a large hydraulic resistance for the free flow of working fluid from the annular space into the internal cavity of the column of flushing pipes and back, see, n Example [1-3]. A feature of these devices is the presence of a jet apparatus with a structurally missing central channel in the direction of fluid flow, which also prevents the acceleration of the process of lowering the cavitation-wave generator into the well. To eliminate these drawbacks, structures traditionally used in the practice of well construction cannot be used to carry out direct and reverse flushing of pipes, based on providing access to the fluid from the annular space by opening circulation channels using a metal ball discharged into the column or cut cork hollow finger [ 4, 5]. This is explained by the fact that these structures do not have the ability to work in a multi-cycle mode and require them to rise to the earth's surface in order to bring them to their initial working condition, and also exclude the possibility of multiple start-up of the cavitation-wave generator to stimulate productive layers of high power (about 100-300 m and more) and length (when located within the thickness of the reservoir with a canopy or a horizontal trunk with a length of about 200-400 m or more). This, with obvious complexity, makes their use in cavitation-wave underground equipment impractical (see diagram on page 107 in [7]). As a result, during the accelerated descent of pipes (candles) into the well, it is necessary to periodically partially or fill them up to the top with liquid using a pump unit. In the case of accelerated lifting of the column of flushing pipes, it becomes necessary to pour fluid into the annular (annular) space to maintain its level at a predetermined depth, which is explained by the presence of a piston effect that creates a large amount of released well space due to the low natural flow velocity of the fluid through cavitation channels from the internal cavity pipes in the annulus. This complicates the process of separation raised from the well pipe due to the need to remove them delivered to the surface of the liquid residues. All this increases the complexity of downhole operations and leads to a very large expenditure of time for carrying out tripping operations in the overall balance of time spent on cavitation-wave processing of the productive formation.

These drawbacks are eliminated in the device for enhancing oil recovery of wells by incorporating a multi-cycle circulating valve assembly in the form of an annular system of reverse peripheral valves (see p. 153-154 in [7]).

This device is the closest in technological essence to the proposed device for enhancing oil recovery of wells and contains a cavitation-wave generator, which is lowered into the perforation interval of the productive formation, connected through a high-cycle circulating valve assembly to the lower end of the flushing pipe, as well as wellhead sealing and lowering equipment, a container with a working fluid and a pumping unit for its injection into the column of flushing pipes.

In this device, a multi-cycle circulating valve assembly is made in the form of a socket with a system of non-return peripheral ball valves, commonly used in units with low requirements for tightness of the locking elements. This design to ensure complete tightness eliminates the possibility of sealing valves with rubber materials, which leads to leakage of fluid when it is supplied under pressure into the channels of the cavitation wave generator. Making the seat of ball valves in the form of a tapered bore with a larger diameter base facing the inside of the nozzle implies a hermetic fixing in the thickness of the walls of the last row of nozzles with the indicated openings. This requires a significant increase in the wall thickness of the nozzle, and the small diameters of the outlet ports necessitate the use of a large number of ball valves with a diameter close to them. These drawbacks complicate the design of the considered multi-cycle circulation valve assembly and lead to a decrease in the reliability of the device as a whole. In addition, the placement of ball valves in the thickness of the walls of the nozzle leads to a significant increase in the outer diameter of the high-cycle circulation valve assembly exceeding the outer diameter of the couplings (D = 89 mm), widely used in the composition of the tubing-73 mm diameter tubing [8] that does not allow for cavitation-wave processing of productive layers in the boreholes of small diameter.

The invention solves the problem of eliminating the above disadvantages.

To achieve this technical result in the proposed device for enhanced oil recovery of wells, containing a cavitation-wave generator, which is lowered into the perforation interval of a productive formation, connected through a high-cycle circulating valve assembly to the lower end of the flushing pipe string, as well as wellhead sealing and launch and lifting equipment, capacity with the working fluid and pumping unit for its injection into the column of flushing pipes, a multi-cycle circulating valve assembly is made in The idea of a pipe coupling housing having a blind hole located along its main longitudinal axis in the upper part, provided with at least one radial channel hydraulically connected with the annular space, while the top of the blind hole is equipped with a seat for spring-mounted located above it with an annular gap the locking member, and the passage of the working fluid from the column of flushing pipes to the cavitation-wave generator is carried out using at least one peripherally located in the body of the body odolnogo through hole with a non-circular cross-sectional shape.

Distinctive features of the proposed device for enhancing oil recovery of wells from the above mentioned device closest to it is the execution of a multi-cycle circulating valve assembly in the form of a pipe coupling housing having a blind hole located along its main longitudinal axis in the upper part, equipped with at least one radial hole a channel hydraulically connected to the annulus; equipping the top of the blind hole with a saddle for seating a spring-loaded closure member located above it with an annular gap; the passage of the working fluid from the column wash pipes to the cavitation-wave generator using at least one peripherally located in the body of the body of the longitudinal through hole with a non-circular cross-section.

The proposed device is illustrated by the drawings shown in FIG. 1-4.

FIG. 1 shows a general view of the downhole part of the device.

FIG. 2 is a general view of a high-cycle circulating valve assembly of the device with a longitudinal section.

FIG. 3 shows section A-A in FIG. 2

FIG. 4 shows a possible embodiment of a multi-cycle circulating valve assembly of the device along section A-A.

A device for enhancing oil recovery of wells includes a well part (Fig. 1) containing a cavitation-wave generator 2, which is lowered into the perforation interval of the productive formation 1, connected through a high-cycle circulation valve unit 3 to the lower end of the flushing pipe column 4, which usually tubing with a diameter of 73 mm is used. At the same time, the wave cavitation generator 2 is connected to the high-cycle circulating valve assembly 3 by means of the coupling 5 of the tubing and the pipe 6 in the form of a tubing segment, which serves as a protective cover for the filter 7 of the cavitation-wave generator 2. In turn, the high-cycle circulation valve assembly 3 is connected with the lower end of the column flushing pipe 4 through the safety pipe 8 in the form of a tubing cut and coupling 9 tubing. All this design is a compact borehole cavitation wave module (SCR - module) with a length of not more than 1.2-1.5 m, pre-assembled at the production base or on the walkways for underground well repair. The ground part of the device includes a typical wellhead sealing and launch equipment, a container with a working fluid and a pumping unit for its injection into the column of flushing pipes 4 (not shown in Fig. 1).

The wave cavitation generator 2 has one of the well-known structures, for example, according to the patent of the Russian Federation [3], and the multi-cycle circulation valve unit 3 is made in the form of a pipe coupling body 10 (Fig. 2), which has a blind end located along its main longitudinal axis an opening 11 provided with at least one radial channel 12 hydraulically connected with the annulus. At the same time, the top of the blind hole 11 is equipped with a seat 13 for seating a valve member located above it with an annular gap, made in the form of a cone valve 14 with a rubber o-ring 15. The cone valve 14 is located in the guide cup 16, tightly covering the saddle 13 and rigidly fixed with screws 17 on the body of the housing 10. At the same time, the guide cup 16 has wide lateral and peripheral bottom windows for free access of the working fluid to the cone valve 14 and the blind hole 11. The cone valve 14 is provided with axial bar the shaft 18, passed through the Central bottom hole of the guide Cup 16, and spring relative to the outer bottom surface of the latter using a compression spring 19, fixed on the shank 18 with lock nuts 20. For the passage of the working fluid from the column of flushing tubes 4 to the cavitation-wave generator 2 (see Fig. 1) in the body of the housing 10 (see Fig. 2) made at least one peripherally positioned longitudinal through hole 21 with a non-circular cross-section, allowing by increasing, thus, its n to minimize the hydraulic pressure loss of the working fluid. Depending on the operational requirements, the high-cycle circulation valve assembly of the device, according to structurally and technologically justified requirements, implies the presence of no more than three radial channels 12 and the corresponding number of longitudinal through holes 21 (see Fig. 3). In this case, the total cross-sectional area of the radial channels 12 must be equal to or exceed the cross-sectional area of the blind hole 11. Moreover, to reduce local losses of fluid pressure, the radial channels 12 can be made at an angle of up to 45 ° to the main longitudinal axis of the housing 10. Such a design of the considered multi-cycle circulating valve assembly of the device compared to a design having one radial channel 12 and one longitudinal through hole 21 (Fig. 4), it is necessary for the operation of the device in flat and horizontal boreholes in the case of overlapping of one radial channel 12 with the lower contact surface of the ph tra in completion fluids during the move or stop it SLE - module. The design of the high-cycle circulating valve assembly 3 (see FIG. 1) of the device does not exclude the possibility of exchanging one radial channel 12, as shown in FIG. 4, two to three channels of smaller diameter, located in the same longitudinal plane of the housing 10, which, if necessary, will maximize the cross-sectional area of the longitudinal through hole 21 by increasing the central angle and the length of the segment of the ring, which is its geometric shape (see Fig. 4 ).

The operation of the device for enhanced oil recovery wells is as follows.

After the SCV module is attached, using the coupling 9 to the lower end of the wash pipe string 4 (see Fig. 1), the latter is launched into the well before the cavitation-wave generator 2 enters the perforation interval (filter) of the reservoir 1. At the same time, the fluid that is in the well, as the column of flushing pipes 4 is lowered into its internal cavity from the annulus partially through the cavitation channels, and mainly through the radial channel 12 (or 2-3 channels) through the blind hole 11 and the annular clearance of the cone valve 14 (see Fig. 2 and 3), thus ensuring the possibility of accelerated descent of downhole equipment to a predetermined depth. If there is a flushing fluid in the well, it is replaced with a working fluid (mainly oil) by backwashing while the SCR module is located at the bottomhole. After that, the cavitation-wave generator 2 is installed (see FIG. 1) at the lower boundary of the perforation interval of the reservoir 1 and its cavitation-wave treatment is started. The processing process is as follows. From the tank with the help of the pumping unit into the column of flushing pipes 4 they start to inject the working fluid with increasing its speed and pressure to the calculated values. In this case, under the action of a pressure differential of about 1-2 atm. when the spring is compressed, the downward cone valve 14 moves with its subsequent landing in the saddle 13 with reliable sealing of their contacting working surfaces, provided by a rubber sealing ring 15. As a result, the entire flow of the working fluid enters through cavitation filter 7 (see Fig. 1) -wave generator 2, where it is twisted, compacted, stabilized and under the action of centrifugal forces and pressure is pushed into the cavitation channels and ejected from them in the form of turbulent high-speed jets n When accompanied by an instantaneous local discontinuity of the continuity of a liquid medium with the formation of a multitude of bubbles and cavities filled with a vapor – gas mixture. Bubbles and cavities collapse when moved to the area of reduced pressure, generating hydraulic shocks of large destructive forces and accompanying sound waves in a wide range of frequencies when vibrations and resonant phenomena occur in the bottomhole zone with transfer of these processes to large distances from the cavitation generator 2 into pores and cracks reservoir 1. This leads to the release of the reservoir 1 from clogging materials and the creation of favorable conditions for increasing the flow of hydrocarbons in well The process of cavitation-wave processing of the productive formation 1 is carried out with a slow movement of the SCR - module in the perforation interval by the amount of lifting of the pipe or candle of the column of washing pipes 4. Then, after the circulation of the working fluid through the cavitation channels is stopped, the pipe or candles are unscrewed from the column of washing pipes 4 and the process the work of the cavitation wave generator 2 is resumed. Work in a similar mode continue until the cavitation-wave generator 2 reaches the upper boundary of the perforation interval. After that, the flow of the working fluid to the cavitation-wave generator 2 is stopped and the lifting of the entire column and the bottomhole drilling equipment to the surface begins. When this cone valve 14 under the action of the compression spring 19 (see Fig. 2) occupies the initial position, thus providing a free flow of working fluid from the internal cavity of the column of flushing pipes 4 (see Fig. 1) into the annulus.

The proposed device for enhanced oil recovery of wells allows, with high reliability, separation of circulating fluid flows to ensure the possibility of accelerated descent and recovery of downhole equipment, to provide, if necessary, a quick replacement of one fluid for another, as well as conducting cavitation-wave processing of productive layers in small-bore wells. . At the same time, the proposed device, unlike the known devices, will allow the well to be put into trial operation by the compressor method not only in the central but also in the ring system [5] by supplying a multi-cycle circulating valve assembly to the radial channels through the annular space oil and gas well with the subsequent rise of the gas-liquid mixture along the tubing. This will provide an opportunity to quickly and repeatedly, without extracting the SCR-module from the well, to evaluate the efficiency of cavitation-wave processing of deep-lying productive formations, as well as, if necessary, to produce hard-to-recover high-density viscous oils while increasing their yield due to cavitation and gas factors.

Used sources:

1. RF patent №2047729, cl. E21B 28 / 00,1995. 1992

2. RF patent №2315858, cl. Е21В 43/18, 2008. 2006

3. RF patent №2493360, cl. Е21В 43/18, 2012.

4. Pustovoitenko I.P. Warning and methods to eliminate accidents and complications in drilling: A manual for vocational education. - M .: Nedra, 1987. - 237 p., P. 203.

5. Development and operation of oil and gas fields. Ants I.M. and others. Publisher 3rd, revised and enlarged. M., publishing house "Nedra", 1970, 448 pages, p. 231-241.

6. Ryazantsev N.F., Belyakov N.V., Domashchenko G.M. Test wells in the drilling process (reference book). - M .: Publishing house "Fizmatknig", 2004. 408 p., P. 238-247.

7. Ibragimov L.Kh., Mishchenko I.T., Cheloyants D.K. Intensification of oil production. - M .: Nedra, Science, 2000. - 414 p., P. 107, p. 153-155.

8. Iogansen K.V. Satellite driller. M., Nedra, 1981. 199 p., P. 56-58.

Claims (1)

A device for enhancing oil recovery of wells, containing a cavitation-wave generator, which is lowered into the perforation interval of a productive formation, connected through a high-cycle circulating valve assembly to the lower end of the flushing pipe column, as well as wellhead sealing and launch-lifting equipment, capacity with working fluid and pump unit for its discharge into the column of flushing pipes, characterized in that the high-cycle circulating valve assembly is made in the form of a pipe coupling housing having In the upper part there is a blind hole located along its main longitudinal axis, provided with at least one radial channel hydraulically connected with the annular space, while the top of the blind hole is equipped with a seat for fitting a spring-loaded locking member located above it with an annular gap, and the passage of working fluid from the column the flushing tubes to the cavitation-wave generator are made with at least one longitudinal through hole with a transverse non-circular cross section.

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