RU2308593C1 - Device for well fluid lifting at later well development stages - Google Patents

Abstract

FIELD: oil production, particularly to lift fluid from periodically flowing well under low reservoir pressure.

SUBSTANCE: device comprises double pipe string including inner and outer pipe strings arranged in well. Produced fluid lifting means is installed at lower end of inner pipe string. The produced fluid lifting means is made as two-chamber activator including high-pressure chamber and vacuum one. The activator is arranged on outer pipe string support. Each chamber has orifices in bottom thereof and is provided with ball valve. Contraction-diffuser nozzles are created in side surface of high-pressure chamber so that the nozzles are distributed along helical line and shifted one from another by 360°:2n angle, where n is number of nozzles in one helical line turn. Contraction part of inner chamber wall is of cylindrical shape. Diffuser part thereof is shaped as truncated cone. Cylindrical orifices are made in side surface of vacuum chamber. Working agent is gas.

EFFECT: possibility of gas injection in pipe string, increased cost efficiency and simplified technology, possibility to measure reservoir pressure and temperature at well bottom.

4 cl, 5 dwg

Description

The invention relates to the oil industry and can be used to lift fluid from wells, in particular from wells at low reservoir pressures, of a late stage of development as reservoir energy is depleted.

A known double-row lift system, including external pipes (air column) of large diameter, lowered to the filter zone of the well, the inner row of pipes (lifting column) of smaller diameter, lowered under the liquid level to a depth, while the working agent is pumped into the annulus between the air and lifting columns, and a mixture of air (gas) and liquid rises to the surface along the lifting column ("Fundamentals of oil and gas business", V. Muravv. M .: Nedra. 1967, p. 158, Fig. 89 b).

The disadvantage of this method is that in the initial period of the call to supply gas to the well, it is necessary to pump gas under high pressure, which is unacceptable by technical requirements for the production casing. In wells in which productive formations lie at a depth of 2500 m or more, in order to overcome the hydrostatic pressure in the lifting pipes, it is necessary to pump gas under a pressure of 250 atm or more (since due to the lack of separation between the annulus and annulus, the pressure is transferred to the production string) , while the maximum allowable internal pressure for the production casing is 150 atm.

A known method of lifting fluid from a well and a device for its implementation (gas piston plunger pump) (patent RU No. 2221133, ЕВВ 43/00, publication 2001.07.20). In terms of the method, this is a method of raising liquid from a well, including descent of a double pipe string into the well, separation of the annulus, installing a plunger pump in the lower section of the inner column and injecting the working agent under pressure into the annulus, venting the gas, restoring gas pressure and maintaining it due to pumping from the compressor. In the part of the device, this is a device for lifting fluid from a well, consisting of a plunger pair installed in the pipe of the inner column, having a seat and placed with a gap in the pipe of the outer column, while the sleeve and plunger are made in the form of glasses with holes in the bottom, normally closed ball valves, and between the seat of the plunger and the seat of the sleeve there is a gap forming an annular cavity through openings in the pipe connected to the annular space, which is below isolated from communication with the well.

Its disadvantage is the presence of moving rubbing parts, for example, a pair of plunger sleeves, which significantly reduces the service life of the device, as well as the inability to conduct research on the annulus, i.e. tracking dynamic and static levels due to the presence of a packer (see description of Figure 3). It is impossible to construct a long sleeve (for example, more than 10 meters), the stroke length of the plunger is limited, and productivity will be low, as the cycle time is a sufficiently long period of time (gas injection and venting).

The objective of the invention is to develop a cost-effective and technologically simplified installation for lifting liquids, in particular, those who stopped flowing or periodically flowing wells in the late period of development of fields with low reservoir pressures, as well as the possibility of tracking static and dynamic levels in the annulus, measuring the temperature at the bottom and reservoir pressure without lifting the tubing string.

The technical result achieved by the invention consists, in particular, in reducing the consumption of the working agent, increasing the reliability and efficiency of the device at a late stage of development under low reservoir pressures without replacing the underground equipment from the beginning of well development to its liquidation, i.e. decades.

The problem is solved in that the device for lifting liquid from the well, like the prototype, contains a double pipe string: internal and external, installed in the well, means for lifting the produced fluid, installed on some lower section of the inner pipe string, unlike the prototype tool for lifting the production fluid, it is made in the form of a two-chamber activator: a rarefaction chamber and a high pressure chamber, and is placed on the lower end of the inner pipe string, mounted on a support made on the lower end e inside the outer pipe string, while cylindrical holes are made on the lateral surface of the rarefaction chamber, and confusor-diffuser nozzles are made on the lateral surface of the high-pressure chamber along a helical line with an offset of 360 ° relative to the nozzles of the adjacent coil, where n is the number nozzles in one turn, equal to 6-24, preferably 24, moreover, nozzles of confuser shape located on the inner side of the chamber wall have a cylindrical shape, and part of the nozzles of diffuser shape located on the outer side of the walls and chambers, having the shape of a truncated cone, the angle between the axes of the cylindrical and conical shapes of the nozzles is 20-30 °, preferably 25 °, the bottom of each chamber is made with an axial hole and equipped with a ball valve, gas is used as a working agent, which is pumped into the inner column pipes. The nozzle has confuser and diffuser parts, while the ratio of the length of the confuser part is approximately two times less than the length of the diffuser part.

New and distinctive features of the claimed invention are:

- means for lifting the produced fluid is made in the form of a two-chamber activator, consisting of a vacuum chamber and a high pressure chamber,

- on the bottom of each chamber made axial holes on which ball valves are installed,

- on the side surface of the high-pressure chamber, nozzles of confuser-diffuser shape are made along a helical line with an offset of 360 °: 2n, where n is the number of nozzles in one turn equal to 6-24,

- the confuser part of the nozzles on the inner side of the chamber wall has a cylindrical shape, and the diffuser part on the outer side of the chamber wall has the shape of a truncated cone, the angle between the axes of the cylindrical and conical shapes is 20-30 °, preferably 25 °.

- cylindrical holes are made on the side surface of the rarefaction chamber, and the total cross-sectional area of these holes is larger than the cross-sectional area of the hole at the bottom of the chamber,

- the ratio of the length of the confuser part of the nozzle is approximately two times less than the length of the diffuser part,

- a two-chamber activator is installed on the lower end of the inner pipe string,

- gas is used as a working agent, which is pumped into the inner pipe string,

- the lower part of the two-chamber activator is mounted on a support made in a shoe inside the outer pipe string.

To create a deep depression on the bottom-hole zone of the formation, the tubing string is lowered to the top of the formation (to the upper perforations), the liquid is lifted by minimizing the weight of the liquid column in the riser by mixing the formation fluid with gas, as well as the energy of compressed gas converted by a two-chamber activator. The tubing is lowered to the top of the formation in order to thereby lift the fluid at the lowest dynamic levels.

A two-chamber activator, mounted on a support made in a shoe inside the outer pipe string, divides the annulus and annulus, while the annular space is formed by the outer pipe string and production string.

The diameter of the inner pipes is selected depending on the diameter of the outer pipes and the capabilities of the well, the technological mode of its operation. The execution of the nozzles along the helix and their displacement relative to the nozzles of the adjacent coil, their size and quantity provide the turbulence mode: the smaller the gas bubbles, the better the gas-liquid mixture that rises to the surface.

The invention meets the condition of "inventive step", as it is not obvious from the prior art for a specialist.

The invention is industrially applicable, since the design of the device can be successfully implemented in oil and gas companies and used for the operation of wells by the compressor-fountain gas-lift method.

Figure 1 shows a General diagram of a device for lifting fluid from a well in the late stages of development. Figure 2 shows a General view of the two-chamber activator. Figure 3 shows a General view of the nozzle confuser-diffuser shape.

A device for lifting liquid from a well consists of an inner pipe string 1 concentrically located in the outer string of the tubing 2. In the cavity of the outer string of the tubing 2 at its lower end there is a support 3, on which a two-chamber activator 4. is mounted. Two-chamber activator 4 consists of a high-pressure chamber 5 (FIG. 2), the side wall of which is made with nozzles 6 having a confuser shape 7 and a diffuser shape 8 (FIG. 3), and a rarefaction chamber 9 with cylindrical openings 10 in the side wall. In the lower part of the two-chamber activator, in the bottom of the high-pressure chamber 5 and in the bottom of the rarefaction chamber 9, axial holes are made, which together with the balls 11 form check valves. A two-chamber activator 4 is fixed (placed) at the lower end of the column of inner pipes 1.

The device in the compressor mode (Fig. 4) works as follows: working agent — gas is pumped into the column of inner pipes 1, gas enters the high-pressure chamber 5 and, through nozzles 6, breaks out into the annulus 12 formed by the inner column 1 and the outer column copressor pipes 2; in the diffuser part 8 of the nozzles, the pressure in the gas flow decreases and the speed increases, a vacuum (ejector effect) is created, the ball 11 in the rarefaction chamber 9 rises and the formation fluid enters the annulus 12, where it mixes with the gas and rises to the surface. In the periodic flowing mode, under the influence of reservoir pressure, the balls 11 are open (Fig. 5), the liquid passes through the rarefaction chambers 9 and high pressure 5 through the column of inner pipes 1, and also along the annular space 12 rises to the surface. No gas is injected. In this case, the column of inner pipes is also a lifting elevator.

The operation of the device in the later stages of the stopped flowing or periodically flowing wells is provided as a result of the equipment of the claimed device. The claimed device in comparison with the prototype allows to simplify the design.

The use of this invention also allows studies to measure reservoir pressure and bottomhole temperature without raising the tubing string, as well as measure dynamic and static levels in the annulus. A device for lifting liquid under appropriate conditions can be successfully used instead of expensive electric submersible and sucker-rod installations and pumps, especially at the final stages of field development, as well as in oil production from wells with a depth of 2500 m with ultra-low reservoir pressure.

Claims (4)

1. A device for lifting liquid from a well, comprising a double pipe string located in the well, means for lifting the production fluid located on a lower portion of the inner pipe string using a working agent, characterized in that the means for lifting the production fluid is made in the form a two-chamber activator: a high-pressure chamber and a rarefaction chamber, and is located on the lower end of the inner pipe string, mounted on a support made on the lower end inside the outer pipe string, while on the side holes of a cylindrical shape are made on the surface of the rarefaction chamber, and confuser-diffuser nozzles are made along a helical line with an offset of 360 ° relative to the nozzles of the adjacent turn relative to the nozzles of the adjacent turn, on the lateral surface of the high-pressure chamber, where n is the number of nozzles in one turn, the bottom of each chamber is made with axial hole and equipped with a ball valve, gas was used as a working agent, while the device allows it to be pumped into the inner pipe string. 2. The device according to claim 1, characterized in that the nozzle has a confuser and diffuser part, and the confuser part of the nozzle has a cylindrical shape in the inner wall of the activator high-pressure chamber, and the diffuser part has the shape of a truncated cone in the outer wall of the chamber, while the length of the confuser parts are approximately half the length of the diffuser part. 3. The device according to claim 1, characterized in that the angle between the axes of the cylindrical and conical shape of the nozzles is 20-30 °. 4. The device according to claim 1, characterized in that the number of nozzles in one turn is 6-24.

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