RU2314411C1 - Pump-vacuum device for well cleaning of sand plug - Google Patents

Abstract

FIELD: oil well operation and repair, particularly to clean well of sand plugs and mud with the use of coiled tubing in the case of abnormally low reservoir pressures.

SUBSTANCE: device comprises jet pump, separation unit and damage unit. The separation unit comprises connection pipe coaxially arranged in body and defining annular sucking channel, as well as upper and lower packing members connected to body. Jet pump is located over separation unit and has sucking annular cavity. Central and lower connection pipe ends, as well as upper and central body parts have radial circulation orifices. Central parts of the tubes are connected with each other by means of intermediate support nut. Tubes of connection pipe and upper and lower body parts are connected through upper and lower support nuts correspondingly. The nuts have radial orifices formed so that radial orifice of upper support nut is inclined upwards and that of lower support nut is directed downwards relatively device axis. Upper support bush is installed in sleeve so that annular space is defined in-between. Upper and lower packing members are spring-loaded and installed over intermediate and lower support nuts correspondingly. Jet pump and separation unit have common sucking vacuum line.

EFFECT: increased efficiency of sand plug breakage and removal with the use of coiled tubing.

3 cl, 3 dwg

Description

The invention relates to the operation and repair of wells and can be used to clean wells from sand plugs and sludge using coiled tubing under conditions of abnormally low reservoir pressure (ANPD).

Analysis of the existing level showed the following:

A device for washing sand plugs is known, consisting of a separation unit, including a nozzle, coaxially mounted in the housing, with the formation of a suction annular channel (annular cavity), upper and lower packing elements (elastic cuffs) located on the housing, and a fracture assembly rigidly connected between themselves and having a common axial hydraulic channel (see AS No. 1081334 dated 02.21.83 according to CL 21/00, published in OB No. 11, 1984). The device as a site of destruction contains a tip or various designs of fittings and nozzles.

The disadvantage of this device is the low efficiency of the destruction and removal of sand plugs, due to several reasons:

- the lack of a jet pump in the device does not allow to reduce the pressure in the sub-packer zone below the hydrostatic, which leads to the absorption of the washing fluid and contamination of the reservoir and does not allow the removal of mechanical particles to the surface;

- the rigid connection of the packer elements with the device case does not allow the use of coiled tubing, since during the descent of the device and its further advancement during the destruction of the sand plug, it is necessary to overcome the great force arising from the friction of the packer elements against the walls of tubing (tubing);

- when promoting the device, the abrasion of the packer elements occurs, which does not ensure the reliability of the packing of the tubing annulus;

- the use of the hydro-monitor effect of a liquid jet ensures the destruction of only loose sand plugs.

As a prototype, a device for cleaning sand plugs was described, described in the method of washing wells (see AS No. 106714 from 10.16.54, class E21B 21/00). The device consists of a jet pump, a separation unit, including a nozzle coaxially mounted in the housing (double casing) with the formation of a suction annular channel (annular space), upper and lower packing elements (self-sealing cuffs) located on the housing, and a destruction unit, rigidly connected between themselves and having a common axial hydraulic channel. In the device, the jet pump is located under the separation unit, and contains nozzles as a destruction unit.

The disadvantage of this device is the low efficiency of the destruction and removal of sand plugs, due to several reasons:

- the jet pump is installed under the separation node, i.e. directly immersed in the sand pulp, which can lead to clogging of the channels and the termination of its work;

- the immobility of the packer elements does not allow the device to be used when working with coiled tubing, since coiled tubing does not allow the force necessary to overcome the friction forces of the packer elements against the tubing walls arising both when the device is advanced to a given depth and during the destruction of the sand plug ;

- abrasion of the packing elements during the descent of the tubing reduces the reliability of separation of the above-packer and sub-packer zones;

- washing sand plugs with a jet of injected liquid ensures the destruction of only loose sand plugs and does not allow to destroy cemented sand plugs.

The technical result that can be obtained by carrying out the invention provides an increase in the efficiency of destruction and removal of sand plugs using coiled tubing due to:

- the special design of the moving packer elements of the separation unit and the hydraulic connections of the device, providing constant sealing of the annulus and the movement of the device during operation without friction against the tubing walls;

- installation of a jet pump above the separation unit, as a result of which a vacuum is created in the sub-packer zone and the sand mixture is sucked, improving the conditions for transporting sludge to the surface;

- providing hydromechanical effects on the sand cork.

The technical result is achieved using a known device consisting of a jet pump, a separation unit, including a nozzle, coaxially mounted in the housing with the formation of a suction annular channel, the upper and lower packing elements located on the housing, and the destruction unit, rigidly interconnected and having a common axial hydraulic channel.

According to the invention, the jet pump is located above the separation unit and has a suction annular cavity.

In the separation unit, the nozzle and the housing are made detachable, while the nozzle in the middle and lower parts, and the housing in the upper and middle parts have radial circulation holes, and the radial circulation holes of the nozzle are hydraulically connected to the axial hydraulic channel of the device, and the radial circulation holes of the housing are with a suction ring channel. The pipes of the middle part of the body are connected by an intermediate support nut, the pipes of the nozzle and the body in the upper and lower parts are connected by the upper and lower support nuts, respectively, having radial holes with an upward slope in the upper support nut and a downward slope in the lower support nut relative to the axis of the device. Moreover, the upper supporting nut is installed in the sleeve with the formation of an annular cavity between them.

On the housing at the level of its radial circulation holes, spring-loaded vacuum distribution bushings are additionally installed, each with an internal annular groove.

The upper and lower packer elements are spring loaded and mounted above the intermediate support nut and lower support nut, respectively. Each packer element consists of a distribution sleeve with a seating protrusion in the upper part under the inner annular groove of each vacuum distribution sleeve. Each distribution sleeve has an inner annular groove connected to its radial holes and hydraulically connected to the radial circulation holes of the nozzle. A seal made in the form of a cylinder with an external trapezoidal rim in the middle part is mounted on each distribution sleeve using the upper and lower nuts, and split anchor rings are installed above and below it.

The inkjet pump and the isolation unit have a common suction vacuum line formed by the intake ring cavity of the jet pump, the annular cavity, radial holes with an upward slope relative to the device axis, a suction ring channel and radial holes with a downward inclination with respect to the axis of the isolation unit device.

The claimed invention as a site of destruction contains a hydropercussion device.

The jet pump in the upper part is rigidly connected to the coiled tubing.

Thus, the claimed technical solution meets the criterion of novelty.

The analysis of the inventive step showed the following: from the sources of patent documentation and scientific and technical literature, we have not identified technical solutions that are based on features that match the distinctive features of the claimed technical solution. The technical result achieved is due to the unknown properties of the structural elements of the disconnection unit and the hydraulic connections of the device, which provide constant sealing of the annulus and movement of the device during operation without friction against the tubing walls. The technical solution does not explicitly follow from the prior art, i.e. meets the condition of inventive step.

The design of the claimed device is illustrated by the following drawings:

figure 1 presents a schematic diagram of the main nodes of the pump-vacuum device for cleaning wells from sand plugs;

figure 2 presents the layout of the jet pump and node separation, a longitudinal section;

figure 3 presents the remote element A of the upper packer element.

The inventive device comprises a jet pump 1, a separation unit 2 and a destruction unit 3, rigidly interconnected and having a common axial hydraulic channel 4 (figure 1). The jet pump 1 has an annular cavity 5. In the lower part, the jet pump 1 is rigidly connected to the separation unit 2 (Fig. 2). The separation unit 2 contains a detachable pipe 6 with radial circulation holes 7, 8, made in the middle and lower parts. Radial circulation openings 7, 8 are in fluid communication with a common axial hydraulic channel 4. The detachable pipe 6 is coaxially mounted in the detachable body 9 with the possibility of the formation of a suction annular channel between them 10. The detachable body 9 in the upper and middle parts has radial circulation openings 11, 12 hydraulically connected to the suction annular channel 10. In the middle part, the split housing 9 is connected by an intermediate support nut 13. In the upper part, the split pipe 6 and the split housing 9 are rigidly connected us upper bearing nut 14, and at the bottom - lower bearing nut 15. The upper nut bearing 14 has radial holes 16 formed with a slope upwards, and the lower bearing nut 12 - radial holes 17 downward gradient relative to the tool axis. The upper support nut 14 is installed in the sleeve 18 with the formation of an annular cavity 19 between them. On the detachable body 9 at the level of its radial circulation holes 11, 12 are installed distribution vacuum sleeves 20, 21, each with an inner ring groove 22, 23. Distribution vacuum sleeves 20 , 21 are spring-loaded by springs 24, 25. On the split housing 9, above the intermediate support nut 13 and lower support nut 15, upper and lower packing elements are installed, spring-loaded relative to the hollow split housing 9 by springs 26, 27. erhny and lower packer elements comprise a distribution sleeve 28, 29 (Figure 3). In the upper part, the distribution sleeves 28, 29 have seats 30, 31 under the inner ring grooves 22, 23 of the vacuum distribution sleeves 20, 21. The distribution sleeves 28, 29 have the inner ring grooves 32, 33 and radial holes 34, 35 hydraulically connected to radial circulation openings 7, 8 of the detachable nozzle 6. On the distribution sleeves 28, 29 with the help of the upper nuts 36, 37 and the lower nuts 38, 39, the seals 40, 41 are fixed. The seals 40, 41 are made in the form of a cylinder with an external trapezoidal rim in the middle part , above and under which split anchor rings 42, 43 are installed. The jet pump 1 and the separation unit 2 have a common suction vacuum line formed by a suction annular cavity 2 of the jet pump 1, an annular cavity 19, radial holes 16 with an upward slope with respect to the axis of the device, a suction annular channel 10 and radial holes 17 with a downward slope relative to the axis of the device of the separation unit 2. In the lower part, the separation unit 2 is rigidly connected to the destruction unit 3, presented in the form of a hydropercussion device. The jet pump 1 in the upper part is rigidly connected to a coiled tubing pipe.

Flushing sand-clay plugs is the most common type of work that is carried out in most wells of fields that are at a late stage of operation. At the same time, the use of mobile coiled tubing units with sleeveless long pipes was widespread. The main problems that arise when flushing wells in fields with oil production are the absorption of flushing fluid during the repair process and the pollution of the productive horizon. Cleaning the bottom-hole zone of a well from sand plugs using a column of coiled tubing is carried out, as a rule, by washing the bottom of a well with various liquids on a water or oil basis using nozzles of various designs. To reduce the pressure on the reservoir, flushing wells is used using foam systems, in which foam is prepared at the wellhead in a gas-liquid ejector and fed into a coiled tubing. However, when pumping foam through a column of coiled tubing pipes, high hydraulic losses occur due to the rheology of the foams, as a result of which the hydro-monitor effect of the jet and unloading the coiled tubing pipes to the bottom to destroy the sand plug is not enough. The unit with coiled tubing does not allow the tool to rotate, which makes it impossible to use a drill bit. The use of downhole screw motors for drilling sand plugs is difficult due to the use of foam systems as a circulating agent. In addition, the velocity of the upward flow in the annular space does not provide the removal of sludge. Problems arising in the process of removing sand plugs necessitate the development of new special technological approaches and technical means for the effective removal of sand plugs, while simultaneously maintaining the stability of the reservoir and its reservoir properties. The problem is solved by including in the layout of the bottom of the column of coiled tubing pipes a pump-vacuum device that allows you to create a depression on the formation in the bottomhole zone of the well, provides constant sealing of the annulus with movement of the device without friction against the tubing walls, significantly improves the destruction of the sand plug and the removal of mechanical particles to the surface.

The device operates as follows.

The proposed device is designed based on the conditions of its installation in the layout of the bottom of the column of coiled tubing pipes with a diameter of 38 mm, for operation in tubing with a diameter of 114 mm, which are the most common at the sites of planned implementation. At the end of the coiled tubing pipe, an assembly consisting of a jet pump, a separation unit and a destruction unit is connected. The assembled pump-vacuum device using the M-10 mobile unit is lowered into the tubing through a coiled tubing preventer 10 m below the liquid level and above the sand plug. A washing liquid is supplied to the column of coiled tubing pipes with a flow rate of 4-6 l / s and a pressure of 35 MPa, which ensures erosion of the sand plug and an increase in the velocity of the upward flow in the annulus over the deposition rate of sand particles in the washing liquid. To generate foam on the face, a foaming liquid is used as the working fluid, and formation gas is used as the gaseous agent, i.e. washing is carried out using formation energy. The use of reservoir gas energy intensifies the process of destruction of the sand plug and improves the cleaning of the bottom-hole formation zone. The generation of foam at the bottom allows to increase the flow of flushing fluid into the column of coiled tubing pipes, to ensure the effective operation of the hydraulic shock device, to improve the conditions for transporting sludge to the surface, reduce the pressure of the liquid column above the device and facilitate its working conditions. The pressure of the flushing fluid through a common axial hydraulic channel 4, radial circulation openings 7, 8 of the detachable pipe 6, inner annular grooves 32, 33 and radial openings 34, 35 of the distribution sleeves 28, 29 are transmitted to the seals 40, 41 of the upper and lower packing elements. Seals 40, 41 are extruded with split anchor rings 42, 43 into the tubing annulus, resulting in packing. In this case, split anchor rings 42, 43 are fixed in the tubing, and the upper and lower packing elements remain stationary. When pushing the coiled tubing pipe downward, the detachable pipe 6, the detachable body 9 with the upper support nut 14, the intermediate support nut 13, the lower support nut 15 are lowered, compressing the springs 26, 27. In this case, the vacuum distribution sleeve 20 sits on the seat 30 of the distribution sleeve 28 of the upper packer element. With further lowering, the radial circulation holes 11 of the detachable housing 9 are combined with the inner annular groove 32 and the radial holes 34 of the distribution sleeve 28 of the upper packing element, as a result of which the pressure in the upper packing element is released into the suction annular channel 10, the upper packing element is unpacked and under the action of the spring 26 moves down to the intermediate support nut 13 of the detachable housing 9. Under the action of pressure of the flushing fluid, the upper packing element Packers again and remains motionless. Further lowering leads to the landing of the vacuum distribution sleeve 21 on the seat 31 of the distribution sleeve 29 of the lower packer element. The radial circulation holes 12 of the detachable housing 9 are aligned with the inner annular groove 33 and the radial holes 35 of the distribution sleeve 29 of the lower packer element, as a result of which the pressure in the lower packer element is released into the suction annular channel 10, the lower packer element is unpacked and moves under the action of the spring 27 down to the lower support nut 15. Under the influence of the pressure of the flushing fluid, the lower packer element is again packaged and remains stationary. The process is repeated, thus ensuring a constant sealing of the annular space when moving the device without friction against the tubing walls. Upon reaching the lower end of the hydropercussion device of the sand plug, the device is turned on, destroying the sand plug. The destroyed sand plug through the common suction vacuum line and then the annular space of the tubing is brought to the surface. The constant sealing of the tubing annulus and the pressure created by the jet pump contribute to the suction of the gas-liquid medium, creating the condition for better removal of mechanical particles.

Thus, we can conclude that the proposed technical solution meets the criterion of industrial applicability.

The present invention meets the condition of patentability, as it is new, has an inventive step and is industrially applicable.

Claims (3)

1. A vacuum pumping device for cleaning a well from a sand plug, consisting of a jet pump, a separation unit, including a nozzle coaxially mounted in the housing with the formation of a suction annular channel, upper and lower packing elements located on the housing, and a fracture assembly rigidly connected between each other and having a common axial hydraulic channel, characterized in that the jet pump is located above the separation unit and has a suction annular cavity, and in the separation unit the pipe and the housing are made removable, while the nozzle in the middle and lower parts, and the housing in the upper and middle parts have radial circulation holes, and the radial circulation holes of the nozzle are hydraulically connected to the common axial hydraulic channel of the device, and the radial circulation holes of the body are connected to the suction annular channel, the pipes of the middle part of the body are connected by an intermediate support nut, the pipes of the nozzle and the body in the upper and lower parts are connected by the upper and lower support nuts, respectively, having rad openings with an upward slope in the upper support nut and a downward slope in the lower support nut relative to the axis of the device, the upper support nut being installed in the sleeve with the formation of an annular cavity between them, and spring-loaded vacuum distribution bushings are additionally installed on the housing at the level of its radial circulation holes with an internal annular groove, while the upper and lower packing elements are spring-loaded and mounted above the intermediate support nut and lower support nut, respectively Actually, each packer element consists of a distribution sleeve with a seat in the upper part under the inner annular groove of each vacuum distribution sleeve and having an inner annular groove connected to its radial holes and hydraulically connected to the radial circulation holes of the pipe, to which it is fixed using the upper and a lower nut, a seal made in the form of a cylinder with an external trapezoidal rim in the middle part, above and below which split anchors are installed ring, wherein the jet pump assembly and separation are common suction vacuum line formed by the suction jet pump annular cavity, the annular cavity with radial holes slope upwards relative to the device axis, an annular suction channel and radial holes sloping downwards relative to the axis of the device node separation. 2. A vacuum pumping device for cleaning a well from a sand plug according to claim 1, characterized in that it comprises a hydropercussion device as a fracture assembly. 3. Pump-vacuum device for cleaning wells from sand plugs according to claim 1, characterized in that the jet pump in the upper part is rigidly connected to the coiled tubing.

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