RU79618U1 - GAS SAND SEPARATOR OF SUBMERSIBLE Borehole PUMP FOR OIL PRODUCTION - Google Patents

Abstract

The technical solution relates to devices for gas separation, as well as cleaning the formation fluid from solids in oil wells and can be used in the oil industry to protect submersible pumping equipment mainly after hydraulic fracturing, in the process of well development, as well as in oil production from sand-producing wells with a concentration of solids up to 5 g / l, mainly in wells with a high gas factor. The gas sand separator comprises a housing with a receiving hole, as well as a nozzle located inside the housing and oriented axially. On the outer surface of the nozzle, helical blades are made, forming together with the inner wall of the housing screw channels, the inlet of which is hydraulically connected to the receiving hole of the separator, and the outlet is with the lower open end of the nozzle. The separator includes a hydrocyclone chamber located under the lower end of the nozzle, while a divider is located above the upper end of the nozzle coaxially to the hydrocyclone chamber, which is configured to separate the predominantly liquid phase of the pumped fluid in the peripheral part of the outlet stream from the gas phase in the central part of the stream and the outlet the central part of the flow into the annulus. The technical result achieved is to increase the reliability and durability of a submersible borehole pump by providing effective cleaning of the pumped fluid from both solid and gaseous phases without significantly complicating the device. 3 s.p. f-ly, 4 ill.

Description

The technical solution relates to devices for gas separation, as well as cleaning the formation fluid from solids in oil wells and can be used in the oil industry to protect submersible pumping equipment mainly after hydraulic fracturing, in the process of well development, as well as in oil production from sand-producing wells with a concentration of solids up to 5 g / l, mainly in wells with a high gas factor.

A device for separating solids when pumping fluid from a well with a submersible pump is described in patent RU 66417 U1, 09/10/2007, comprising a housing with a receiving hole, and also a nozzle located inside the housing and oriented in the axial direction. The upper end of the pipe is hydraulically isolated from the inlet of the device, while the device is made with the possibility of hydraulic connection with the intake of the pump from the upper end of the pipe. Two screw blades are made on the outer surface of the nozzle, forming helical channels, the inlet of which is hydraulically connected to the receiving hole of the separator, and the outlet with the lower open end of the nozzle. In this case, the separator includes a hydrocyclone chamber, the upper part of which

located under the lower end of the pipe.

The presence of a helical channel and a hydrocyclone located underneath ensures efficient centrifugal separation of solid particles in the pumped fluid. Due to the large centrifugal force, a low pressure zone forms on the axis of the hydrocyclone, as a result of which gas is sucked from the pumped liquid and a gas column is formed in the central part of the pipe, however, the lack of means for separating the central and peripheral parts of the stream exiting the pipe does not allow using this effect for separating gas from liquid in a separator of the described construction.

Known gas-sand separator submersible borehole pump for oil production, described in patent RU 2212533 C2, 09/20/2003, containing a housing with a receiving hole, as well as coaxial external, central and internal pipes located inside the housing and oriented in the axial direction. The cavity between the outer pipe and the housing is hydraulically isolated from the inlet and connected to the inlet chamber of the pump in the upper part of the cavity. A mesh screw blade is made on the outer surface of the inner pipe, which forms a screw channel, the inlet of which is hydraulically connected to the receiving hole, and the outlet with the lower part of the cavity between the external pipe and the housing. Windows are made in the wall of the inner pipe to separate the predominantly gas phase of the fluid being pumped out, displaced to the axis of the screw channel, allowing gas to escape into the annulus through the cavity

inner pipe. The central nozzle is made with holes for removing particles of mechanical impurities accumulating on the mesh screw blade into the cavity between the inner and central nozzles, which is connected to the sludge collector located below the separator. In this way, centrifugal gas separation and essentially the filtration separation of the solids are carried out simultaneously.

Known gas-sand separator of a submersible borehole pump for oil production, described in copyright certificate SU 1308754 A1, 05/07/1987 containing a housing with a receiving hole, as well as coaxial external and internal pipes located inside the housing and oriented in the axial direction. The upper ends of the nozzles are hydraulically isolated from the inlet. A screw blade is made on the outer surface of the external pipe, which forms a screw channel, the inlet of which is hydraulically connected to the receiving hole, and the outlet through the cavity of the internal pipe is connected by a pump intake. Windows are made in the wall of the external pipe to separate the predominantly gas phase of the pumped fluid and to discharge it into the annulus through the cavity between the external and internal pipes. Below the nozzles there is a flow divider designed to separate the solids concentrated in the peripheral part of the flow coming out of the screw channel from the predominantly liquid phase located in the central part of the stream, as well as to remove the solids to the sludge collector. Thus, simultaneous centrifugal separation of the solids and gas is carried out.

The separator design similar in principle to operation is described in utility patent RU 8409 U1, 11.16.1998, characterized in that the function of the flow divider is performed by an additional mechanical impurity separator of a traditional design, which is located under the separator described above and is hydraulically connected to the outlet of the screw channel. In this separator, the separation of solids occurs after gas separation and is carried out due to the reversal of the flow, as well as due to gravitational deposition of solid particles in the sludge collector during the movement of the stream along the mentioned additional separator. The presence in the composition of the device of actually two separators significantly increases the axial dimension of the device, and also leads to a complication of its design.

The principle of sequential separation of gas and impurities using two separating units is also used in the design of the gas sand separator of a submersible borehole pump for oil production according to the patent US 6382317 B1, 05/07/2002, however, this device performs centrifugal separation of both gaseous and solid phases of the fluid, implemented due to the swirling of the flow using elements sequentially located in the housing, forming the corresponding helical channels.

Utility Model Patent RU 65965 U1, 08/27/2007 describes a gas sand separator for a submersible well pump for oil production, comprising a housing with a receiving hole, and a pipe located inside the housing above the receiving hole of the separator and oriented

axial direction, while the lower ends of the pipe is hydraulically isolated from the inlet of the separator. On the outer surface of the pipe a helical blade is made forming a helical channel, the inlet of which is hydraulically connected to the inlet, and the outlet with the intake of the pump. Windows are made in the wall of the inner pipe to separate the predominantly gas phase of the fluid being pumped, and to discharge it through the cavity of the internal pipe into the annulus. In the upper part of the nozzle there is a jet pump for pumping gas from the nozzle cavity, the liquid line of the jet pump is connected to the outlet of the submersible borehole pump. The use of a jet pump in the described device leads to its complication and decrease in reliability in a real well, in addition, the release of an additional volume of liquid (foam) into the annulus reduces the efficiency and can adversely affect the operation of the pump as a whole.

The closest analogue (prototype) is a gas-sand separator of a submersible well pump for oil production, described in patent RU 48579 U1, 10.27.2005. The separator comprises a housing with a receiving hole, as well as a nozzle located inside the housing and oriented axially, while the upper end relative to the working position of the separator in the well is hydraulically isolated from the receiving hole of the separator, and the separator is made with the possibility of hydraulic connection with the pump intake from the upper end branch pipe. On the outer surface of the pipe a helical blade is made, forming

a helical channel, the input of which is hydraulically connected to the receiving hole, and the output with the lower open end of the pipe.

In the cavity of the nozzle is a flow divider designed to separate the predominantly liquid phase of the pumped fluid from the predominantly gas phase. The divider is an additional pipe located concentrically mentioned. A screw blade is made on the outer surface of the additional nozzle, forming a helical channel, the input of which is hydraulically connected to the output of the screw channel of the main pipe, and the output is made with the possibility of hydraulic connection with the pump intake. Windows are made in the wall of the additional nozzle to separate the predominantly gas phase of the pumped fluid displaced to the axis of the screw channel and to divert it into the annulus through the cavity of the inner pipe and radial channels in the upper part of the pipe, as well as the corresponding holes in the separator body. The described construction is similar in principle to the construction of US Pat. No. 6,382,317, however, the helical channels are arranged concentrically and at the first stage (in the external channel) the solids are separated, and then gas is separated in the internal screw channel.

A common drawback of the analogues described above, including the prototype, is the ineffective mechanism of separation of mechanical impurities and gas, especially for low-production wells with a relatively low flow rate, since the centrifugal force that occurs when the flow moves along the helical

the channel in most cases will be insufficient to completely separate the phases of the flow.

Thus, the task to which the claimed group of utility models is directed is to improve the design of the gas sand separator of a submersible borehole pump for oil production from wells containing solids in the formation fluid to 5 g / l (wells with high natural removal of solids from the reservoir, after hydraulic fracturing operations, in the process of developing wells, etc.), mainly from wells with a high gas factor, including from low production wells.

The technical result achieved by the implementation of the claimed utility model is to increase the reliability and durability of a submersible well pump by providing effective cleaning of the pumped fluid from both solid and gaseous phases without significantly complicating the device.

The gas-sand separator of a submersible borehole pump for oil production, ensuring the achievement of the above technical result, comprises a housing with a receiving hole, as well as a nozzle located inside the housing and oriented axially. The upper end of the nozzle relative to the working position of the separator in the well is hydraulically isolated from the inlet, and the separator is made with the possibility of hydraulic connection with the pump intake from the side of the upper end of the nozzle. On the outer surface of the pipe is made

at least one screw blade, forming together with the inner wall of the housing a helical channel, the inlet of which is hydraulically connected to the receiving hole of the separator, and the channel output is hydraulically connected to the lower open end of the pipe. The separator is equipped with a flow divider designed to separate the predominantly liquid phase of the pumped fluid from the predominantly gas phase. In this case, in contrast to the prototype, the separator includes a hydrocyclone chamber located under the lower end of the nozzle, while the flow divider is located coaxially to the hydrocyclone chamber above the upper end of the nozzle and is configured to separate the peripheral part of the outgoing stream from the central part of the stream and the central part flow into the annulus.

In addition, in the particular case of the implementation of the utility model, the flow divider is a plug installed in the body cavity with a central hole made on the nozzle side and designed to pass the central part of the flow, containing mainly the gas phase of the pumped fluid, and the divider is made with the possibility of hydraulic connection a central hole with an annular space by means of at least one radial channel and a corresponding hole in the housing, in the peripheral second divider portion near the inner wall of the housing is formed at least one channel for passage of the peripheral part of the stream containing predominantly liquid phase fluid.

In addition, in the particular case of the implementation of the utility model, the separator includes a sludge collector designed for fixing under a hydrocyclone chamber.

In addition, in the particular case of the implementation of the utility model, it is equipped with a safety valve located above the divider and made with the possibility of hydraulic connection of the inlet cavity of the submersible borehole pump with the annular space behind the separator in the direction of flow of the pumped fluid, provided the flow stops through the separator.

The presence of a hydrocyclone chamber provides an increase in the efficiency of separation of mechanical impurities, while conditions are created inside the chamber that lead to the formation of a zone of reduced pressure on the axial line of the separator, into which the gas contained in the pumped fluid is sucked. Moreover, the presence of a flow divider at the outlet of the nozzle in the aforementioned rarefaction zone on the axis of the separator allows you to separate most of the gas phase from the pumped medium and direct the gas into the annulus.

The possibility of implementing a utility model, characterized by the above set of features, is confirmed by the description of the gas-sand separator of a submersible well pump for oil production, made in accordance with this utility model. The description is accompanied by graphic materials, which depict the following:

Figure 1 - gas-sand separator in the context.

Figure 2 - safety valve.

Figure 3 - flow divider.

Figure 4 - diagram of the hydrocyclone chamber.

The submersible borehole pumping unit includes a submersible borehole pump 1, a submersible electric motor 2 with hydraulic protection, a gas sand separator 3 with a safety valve 14, and a sludge collector 15, designed to accumulate solids particles separated in the separator 3.

Above the pump inlet (not shown) a hollow cylindrical casing 16 is tightly fixed, inside of which an electric motor 2 is placed, and a separator 3 and a sludge collector 15 are fixed on the lower open end of the casing 15. Between the wall of the casing 16 and the electric motor 2 there is a gap necessary for normal passage pumped liquid.

The separator 3 includes a housing 4, consisting of a head 5 with a receiving hole 6, a holder 7 and an adapter 8. Inside the head 5 with the help of a sleeve 9 there is a pipe 10 oriented in the axial direction. The upper (output) end of the pipe 10 is located above the receiving hole 6 and is hydraulically isolated relative to it by the sleeve 9. The pipe 10 is equipped with two screw blades 11 located in the upper part of its outer surface. The blades 11 are made integral with the nozzle and together with the inner wall of the head form a two-way screw channel, the input of which is at the level of the inlet 6. The nozzle with

screw blades serves as a screw flow swirl intended for the initial unwinding of the flow and separation of particles of solids from the pumped fluid.

The lower part of the head 5 and the lower part of the nozzle 10 aligned with it form a cylindrical section of the separator, the presence of which prevents the movement of solid particles in the opposite direction during the separation process and, accordingly, the removal of part of the solids through the nozzle 10.

The intake grid 12 prevents large solids from the pumped fluid flow into the separator.

A clip 7 is attached to the lower part of the head 5, inside of which a removable insert 13 is fixed with a cone-shaped inner wall forming the working surface of the hydrocyclone chamber. At the base of the cone of the insert 13 is a removable nozzle 28 with a discharge opening. The insert has a predetermined taper angle, and the nozzle has the corresponding diameter of the discharge opening. The taper angle and the diameter of the discharge opening are selected according to known dependencies or experimentally, taking into account the internal diameter of the nozzle, the characteristics of the pumped liquid, the required capacity of the separator, the size of the separated particles of mechanical impurities, etc.

The separator 3 is made with a single receiving hole, the diameter of which is determined by calculation according to known dependencies, which allows to increase the separation efficiency by increasing the input velocity of the liquid and, accordingly, the growth of centrifugal forces in the hydrocyclone, this

significantly increases the intensity of separation of solids from liquids, since the efficiency of the hydrocyclone is proportional to the square of the tangential flow velocity.

An adapter 8 is attached to the clip 7, designed to connect the separator to the sludge collector 15, which is a few tubing connected to each other with a plug 17 at the lower end. The plug 17 prevents the removal of solids in the well and ensures the flow of working fluid only through the inlet 6.

The separator 3 is equipped with a flow divider 18 located coaxially with the hydrocyclone chamber insert 13 above the upper end of the nozzle 10. The divider 18 is designed to separate the predominantly liquid phase in the peripheral part of the outlet 10 from the predominantly gas phase in the central part of the stream and to discharge the predominantly gas phase of the stream into annulus. The divider 18 is a plug installed in the cavity of the housing, and is made with a Central hole 19 from the side of the pipe, designed to pass mainly the gas phase of the stream. Moreover, the divider is made with the possibility of hydraulic connection of the Central hole with the annular space through the radial channels 20 and the corresponding holes in the head 5 of the housing 4. In the peripheral part of the divider near the inner wall of the head channels 21 are formed for the passage of the predominantly liquid phase of the flow.

The safety valve 14 is located above the divider 18 and is designed to hydraulically connect the pump inlet cavity to the annular space behind the separator along the flow of the pumped fluid, provided the flow stops through the separator. The safety valve includes a housing 22 with a head 23 and bypass holes 24 in the side wall. A spool sleeve 25 is installed inside the housing with bypass holes 26 in the side wall. The sleeve 25 is mounted axially movable. In the lowest position of the sleeve, the bypass holes 24 and 26 are combined and the pumped fluid can move from the annulus to the pump intake. A differential cavity is formed between the sleeve 25 and the head 23 of the housing in such a way that if there is excessive pressure in the cavity of the safety valve (i.e., after placing the safety valve in the well), the direction of the resulting force acting on the spool sleeve will be opposite to the direction of action on the spool flow sleeve pumped liquid coming from the nozzle 10 of the separator. The spool sleeve is preloaded by the spring 27 in the direction of the flow of the pumped medium, and the force generated by the spring 27 is less than the resultant force in any position of the sleeve 25. In addition, the sleeve is equipped with a ball check valve 29, which is capable of blocking the central hole of the sleeve when the fluid moves in the opposite direction after stopping the pump.

The device operates as follows.

Under the pressure of the liquid column in the well, the pumped liquid enters the separator 3 through the inlet 6 and moving along the screw channel formed by the blades 11, acquires a rotational-translational motion, and subsequently under the action of centrifugal forces moves tangentially relative to the wall of the cylindrical part of the hydrocyclone chamber. Inside the hydrocyclone chamber, a conical surface of the phase separation (separation zone) is formed at which the vertical flow rate is zero. An upward flow forms inside this interface, and a downward flow forms outside the said interface (see FIG. 4).

Under the action of centrifugal force, a reduced pressure zone forms on the axis of the hydrocyclone chamber, as a result, gas is sucked from the pumped liquid and accumulates in the central part of the flow to form a gas column, the diameter of which, according to experimental data, can be up to 55% of the diameter of the nozzle 10. Gas, passing through the pipe 10 with an upward flow, it enters the central hole 19 of the divider 18, and then through the channels 20 it enters the annulus, and the liquid separated from the gas flows through the channels 21 and the pump intake.

Solids under the influence of centrifugal force are thrown to the walls of the hydrocyclone chamber and are concentrated mainly in the external downward flow, and a small amount of solids trapped in the upward flow are carried along with it through the pipe 10.

The ejection of solids from the hydrocyclone occurs through the discharge opening of the nozzle 14, from which the liquids with solids enter the sludge trap 15, where solid particles are concentrated in its lower part. In the case of filling the sludge collector 15 and the housing 4 with particles of mechanical impurities, the movement of fluid through the safety valve 14 stops, as a result of which the ball valve 29 closes, and the spool sleeve 25, under the influence of the pressure difference arising from the differential cavity, is lowered and takes its lowest position, compressing the spring 27. Through the combined bypass holes 24 and 26, the formation fluid from the annulus flows directly to the pump intake, thereby avoiding a "dry ode "and the failure of the pump or motor.

The described separator was tested on a special bench installation. According to the test results, the fact of gas separation from a gas-containing liquid was confirmed.

Claims (4)

1. Gas sand separator of a submersible borehole pump for oil production, comprising a housing with a receiving hole, and also a nozzle located inside the housing and oriented in the axial direction, while the upper end of the pipe relative to the working position of the separator in the well is hydraulically isolated from the receiving hole, and the separator is made with the possibility of hydraulic connection with the pump intake from the side of the upper end of the pipe, at least one screw blade is made on the outer surface of the pipe, developing together with the inner wall of the housing a helical channel, the inlet of which is hydraulically connected to the receiving hole of the separator, and the channel output is hydraulically connected to the lower open end of the nozzle, the separator is equipped with a flow divider designed to separate the predominantly liquid phase of the pumped fluid from the predominantly gas phase, characterized in which includes a hydrocyclone chamber located under the lower end of the nozzle, while the flow divider is located coaxially with the hydrocyclone chamber above the upper m by the end of the pipe and is configured to separate the peripheral part of the stream exiting from the pipe from the central part of the stream and divert the central part of the stream to the annulus. 2. The separator according to claim 1, characterized in that the flow divider is a plug installed in the cavity of the housing with a central hole made on the nozzle side and designed to pass the central part of the stream, containing mainly the gas phase of the pumped fluid, while the divider is made with the possibility hydraulic connection of the Central hole with the annular space through at least one radial channel and the corresponding holes in the housing, in the peripheral part of the divider at least one channel is formed near the inner wall of the housing for the passage of the peripheral part of the stream, containing mainly the liquid phase of the fluid. 3. The separator according to claim 1, characterized in that the separator includes a sludge collector designed for fixing under a hydrocyclone chamber. 4. The separator according to claim 1, characterized in that it is equipped with a safety valve located above the divider and made with the possibility of hydraulic connection of the inlet cavity of the submersible borehole pump with the annular space behind the separator in the direction of flow of the pumped fluid, provided the flow stops through the separator.