EA009894B1 - Gas separator - Google Patents

Abstract

A combination liquid and gas separator and jetting tool includes a housing (1) containing a rotatable drum (2), a stator (6) in the inlet end of the housing (1) for swirling a liquid/gas mixture, a rotor (9) attached to the drum (2) for rotation by the mixture; whereby the gas and liquid are separated. The liquid and gas are discharged through separate restricted orifices (28, 32) downstream of the drum. Orifices (44, 59) can be located in a rotating head (43) for cleaning, cutting or other downhole operations.

Description

This invention relates to a gas separator, namely a gas separator used as a linear well equipment for oil and gas drilling and well servicing.

Background of the invention Review of the level of technology

As described in US Pat. No. 6,138,757 (La1O8 et al.), There are cases in the oil and gas industry where gas is injected into a well with a liquid. In depleted wells, maintenance is usually performed using a flexible pipe with jetting means using pressurized fluids, usually nitrogen and water. Working with negative hydrostatic pressure with compressed fluids in the wellbore reduces the likelihood of damage to the well and helps to transport fluids and drill cuttings to the surface. When nitrogen and water are injected as a two-phase fluid, the jet expands after exiting the nozzle, which reduces the impact pressure of the jet. The two-phase flow in the jet nozzle can also be acoustically choked, which limits the flow rate of the jet and its efficiency. In addition, the jet of fluid quickly disperses in the surrounding fluid in the wellbore. All of these factors combine to reduce the effectiveness of a two-phase jet.

Separating the gas from the fluid flow could improve the performance of hydraulic drilling for well operation. A single-phase jet of water has a higher density and stagnation pressure than a jet of a mixture of phases, and therefore would be more efficient than a two-phase jet. Under the conditions under which oil and gas wells are operated, to ensure effective hydraulic drilling, the gas content in the fluid injected from the separator should be less than 1% by volume.

Surrounding a jet of liquid with a separated gas can reduce the intensity of jet dispersion and increase its long range. Many well operations require that a hydraulic drilling device pass through a system of small-diameter pipes and obstacles before passing the treatment systems of large-diameter pipes, downhole equipment in mandrels for securing tools or open boreholes; an increase in jet length will increase the efficiency of hydraulic drilling devices for these operations compared to hydraulic drilling with a single-phase fluid jet.

The use of a pressure jet of fluid with a gas separator will also increase the pressure drop and hydraulic energy of the jet by lowering the pressure in the well during flushing. Increasing pressure and power will allow erosion of a harder material, such as mineral salt deposits, cement and rocks, while increasing power will increase erosion intensity.

An effective gas separator can provide high performance over a relatively wide range of gas fractions in the feed fluid. Usually, this amount of nitrogen is added, which is sufficient to lower the bottomhole pressure up to 50% of the hydrostatic pressure. Under these conditions, the volume fraction of compressed gas in the fluid flow in a flexible pipe is 20-60%. The volume fraction of gas entering the separator may change substantially during single-pass operation due to changes in pressure and temperature with increasing depth of immersion of the tool.

Specified US patent No. 6138757 describes a downhole phase separator for a flexible pipe of small diameter, using the principle of a cyclone separator. This device provides a gas content of less than 5% with an initial gas content in the supplied fluid 30-40%. Cyclone separators use fluid swirl with a set of vanes. This method creates a very high radial acceleration, with the result that separating forces arise. In small-diameter devices, high flow rates create mixing forces with high turbulence, which are superior in magnitude to the separating forces and limit the efficiency of the separation process.

Rotary gas separators are commonly used to create two-phase fluids to eliminate the flow of gas into electric submersible pumps. The rotary gas separator is driven by the pump shaft and rotates at a speed of 3500 or 1750 rpm, depending on the type of electric motor and the power supply source. The separator includes an inductor to increase the pressure of the two-phase flow entering the separator. The flow enters the blade section with a ring, where the flow is twisted, and water or oil moves to the periphery of the section under the action of centrifugal forces. The ring rotates with the paddles, thereby reducing turbulence in the separator. The injection manifold at the top of the separator directs the flow of fluid to the pump, and the gas flow back to the annulus of the well. The declared gas content after separation is less than 10% for a wide range of flow rates and relative gas and liquid contents in the stream.

Linear rotary gas separators are also used in pipelines to separate small volumes of condensate from the gas stream. In separators of this type, a stator is used to direct the swirling flow into the drum, which has rotary vanes in the flow

- 1 009894 gas. The rotor provides rotation of the drum under the action of flow. This type of separator is designed to remove all the liquid from the gas stream, as opposed to the way a small amount of gas is separated from the liquid.

In US patent No. 4047580 (WAITO and others) a method of creating a covering layer on a submerged jet is disclosed, based on the introduction of compressed air through the outer annular space of a coaxial jet nozzle. The air envelope of the jet increases the range of the jet four times. The manufacture of nozzles with an annular channel for gas is quite laborious, especially for hydraulic drilling with a fluid stream under high pressure.

General description of the invention

There is still a need for a linear separator to effectively separate gas from a liquid. The purpose of this invention is to meet this need by creating a relatively simple, compact separator for separating gas from a gas-liquid mixture.

Another object of the invention is to provide a device comprising a combination separator for separating gas from a liquid and a device for hydraulic drilling for downhole operations.

Accordingly, the invention relates to a device for separating gas from a liquid under pressure, comprising a tubular body having inlet and outlet ends, a stator located at the inlet end of the body and designed to tighten the gas-containing liquid supplied to the inlet end of the body, a drum mounted with the possibility of rotation in the specified housing behind the stator in the direction of fluid flow between the inlet and outlet ends of the housing, a rotor located at the inlet end of the drum and serving to bring The drum housing, the end wall located at the rear end of the drum in the direction of flow of fluid through the housing, the fluid outlet openings located at the edges of the end wall and intended to release liquid from the drum, the gas outlet hole located in the center of the end wall and intended for the release of gas from the drum, the outlet for the liquid, located in the housing and used to receive fluid from the hole for the release of fluid and the subsequent release of fluid from the building ca, a gas outlet channel located in the housing and used to receive gas from the gas outlet and subsequent release of gas from the housing, the first flow restriction element located in the fluid outlet channel and intended to narrow the liquid flow during its release from the device , the second element of the flow restriction, located in the gas outlet channel and intended to narrow the gas flow during its release from the device.

According to another embodiment, the invention relates to a method of hydraulic drilling, comprising the steps of passing a two-phase fluid flow through a device for hydraulic drilling, removing gas from a two-phase fluid flow and thus obtaining a gas phase and a liquid phase containing not more than 1% of gas by volume. In another embodiment, the gas phase and the liquid phase are discharged from the device, and the gas phase surrounds the discharge jet of the liquid phase.

According to another embodiment, the invention relates to a method of injecting a two-phase fluid containing gas and liquid into the wellbore and separating the gas phase from the liquid phase, with the result that the gas content in the liquid phase is less than 1% by volume.

Brief Description of the Drawings

The invention will now be described in more detail with reference to the accompanying drawings, in which FIG. 1 is a schematic longitudinal section of a separator device combined with a device for hydraulic drilling in accordance with this invention;

FIG. 2 is a schematic longitudinal section of a second embodiment of a separator device combined with a device for hydraulic drilling in accordance with this invention;

FIG. 3 is a schematic longitudinal section of a separator device combined with a rotary device for hydraulic drilling in accordance with this invention;

FIG. 4 is a schematic longitudinal section of a second embodiment of a separator device combined with a rotary device for hydraulic drilling in accordance with this invention;

FIG. 5 is a schematic longitudinal section of a third embodiment of a separator device combined with a rotary device for hydraulic drilling in accordance with this invention;

- 2 009894 of FIG. 6 is a schematic longitudinal section of a fourth embodiment of a separator device combined with a rotary device for hydraulic drilling in accordance with this invention;

FIG. 7 is a schematic longitudinal section of a fifth embodiment of a separator device combined with a rotary device for hydraulic drilling in accordance with this invention;

FIG. 8 depicts an end view of a separator device combined with the hydraulic drilling device shown in FIG. 7;

FIG. 9 is a perspective view of a stator used in the device shown in FIG. 7; FIG. 10 is a perspective view of the rotor used in the device shown in FIG. 7

Description of a preferred embodiment of the invention

According to FIG. 1, the proposed separator comprises an elongated tubular body 1 comprising a rotating drum 2. The gas-containing liquid is supplied to the input end 3 of the body 1 through an orifice of small diameter 4. The liquid passes through the conical end 5 of the stator 6, which is fixed in the body. The stator 6 has blades 7 connected to the housing 1 and designed to tighten the fluid entering the housing 1. The swirling flow causes the rotor 9 to rotate. The rotor 9 connected to the drum 2 has straight blades 10 parallel to the axis of the drum ensuring tangential flow fluid of small size in the drum 2. The rotor 9 is rotatably held in the stator 6 by the bearing 12. The movement of the fluid flow through the rotor 9 causes the rotor and the drum 2 to rotate.

To the output end of the housing 1 is rotatably attached using a bearing 14 end wall 25 of the drum 2, which has a narrowing. Bearings 12 and 14 are made of materials with a low coefficient of friction and have a small diameter, in order to limit the torque in the support. The bearing 14 is a angular contact ball bearing, while the bearing 12 is a radial plain bearing. Between the rear end of the drum 2 and the rear end 16 of the housing 1 there is a non-contact seal 15. The gas contained in the liquid, which enters the drum 1 through the stator 6 and the rotor 9, is separated from the mixture passing through the conical rear section 18 of the rotor 9, by centripetal acceleration, which causes the liquid 19 to move to the outer side of the drum, and gas 20 to the axis of the drum 2. Since the tangential component of the flow velocity is small, the total flow velocity is minimal, which minimizes the forces of turbulent mixing, which counteract gas separation.

In the preferred case, the rotor 9 has a pressure equalization hole 21 for purging the pressure equalization chamber 22 between the stator and the rotor. The reduced pressure in the chamber 22 reduces the axial load transmitted by the rotating drum 2 to the thrust bearing 12. In the drum 2, holes 23 may also be located near its rear end. The holes 23 are located in the zone of low-velocity fluid flow, which is under a higher pressure than the zone high-speed flow between the stator 6 and the rotor 9. The holes 23 provide the reverse circulation of the fluid, which counteracts the leakage of gas through the space between the housing 1 and the drum 2.

The liquid 19 is released from the drum 2 through the holes 24 at the edges of the end wall 25 of the drum 2. The holes 24 form an annular cross-section space. The liquid flows through the channel 26 at the rear end 16 of the housing 1 to the constriction in the form of a nozzle 28. The gas is discharged through a central axially running siphon tube 30 connected to the rear end wall 25 of the drum 2, the channel 31 and the hole 32 at the rear end 16 of the housing 1 There may be several gas outlets.

The gas outlet hole in the inlet portion of the channel 31 is preferably provided in the form of a sound nozzle that passes the maximum volumetric flow rate of gas expected from this action. Gas dynamics equations are known to those skilled in the art, from which it is possible to calculate the required dimensions of a gas orifice for a given pressure, temperature and flow rate. Liquid nozzles 28 are of such necessary dimensions that provide maximum hydraulic power jet, taking into account the pressure loss from friction in the pipeline. If the flow rate increases, and the component of the gas fraction decreases, the pressure drop and flow rate through the liquid nozzles and gas orifices increase. The liquid entering the gas orifice causes it to block, which reduces the throughput for the gas. Therefore, the gas orifice provides a simple and reliable means of limiting the loss of liquid from the gas separator, while maintaining the pressure and hydraulic energy of the liquid jets by reducing the gas flow rate.

The rear end of the housing 1 in the direction of fluid flow is closed by a hydraulic drilling unit 34, which contains portions of channels 26 and 31, a nozzle 28 and apertures 32. Node 34 is one example of many more complex devices, including rotary hydraulic drilling devices, drilling engines installations and other devices whose operation is based on the restriction of fluid flow.

In a preferred embodiment of the invention, the required size of the gas orifice 32 is made slightly larger than necessary for the maximum gas flow expected for a given

- 3 009894 action. Gas dynamics equations are known to those skilled in the art, from which it is possible to calculate the required dimensions of a gas orifice for a given pressure, temperature and flow rate. Liquid nozzles 28 are made with the size necessary for the pressure flow of the fluid at a given pressure of the jet, taking into account the loss of pressure on friction in the pipeline. If the flow rate of the gas fraction decreases, the fluid begins to flow into the siphon tube 30 and into the hole 32. The throughput of the hole 32 through the two-phase flow is much less than the gas. Therefore, the gas passage opening 32 provides a simple and reliable means of limiting the loss of liquid from the gas separator due to changes in gas flow rate at the inlet that may occur during operation. Bench tests of the gas separator show that fluid loss is 0.6% or less, while the content of the gas fraction at the inlet ranges from 29 to 52%.

An embodiment of the invention shown in FIG. 2 is similar to that shown in FIG. 1, except that the rotor 9 is cylindrical, without a conical rear section, and the front end 36 of the end wall 25 of the drum is tapered to accelerate the flow of fluid into the outlets 24 and eliminate sudden changes in the direction of flow that may cause repeated turbulent mixing of the gas and liquids. The axes of the nozzle 28 and the holes 32 intersect outside the node 34, so that a layer of gas is formed around the jet of liquid. Hole 32 in the embodiment of FIG. 2 has a greater narrowing than the narrowing in the bearing 14 in the embodiment of FIG. one.

FIG. 3 shows the device used in cases requiring rotational motion of the outgoing jet. The device shown in FIG. 3, similar to the device shown in FIG. 1, except that the fluid discharged from the drum 2 through the siphon tube 30 passes through the channels 38 in the rear end of the housing 1 and the central axial channels 39 and 40, respectively, through the brake assembly 42 and the head 43. The brake assembly 42, which includes In itself, the pipe 46, on which the head 43 is located, is rotatably mounted in the housing 1 on bearings 47. The passage of fluid through nozzles 44, which are offset from the longitudinal axis of the head 43, i.e. inclined relative to the end plane of the head 43, causes the rotation of the brake assembly 42 and the head 43 in the housing. The nozzles 44 are located behind the rear end of the housing 1, so that when installing a device for hydraulic drilling in the production oil or gas column 49, the fluid jets will erode internal contamination 50. It should be noted that any rotary engine with an axial flow channel can be used in combination with the separator large enough to accommodate the siphon tube 30. For example, US Patent Application 2005/0109841 (Matush et al.) describes a large-diameter pressure-jet hydraulic rotor having free spaces. o for the passage of the axial flow.

The siphon pipe 30 transmits the gas from the drum 2 to the central outlet 51 in the head 43. The inlet end of the siphon pipe 30 is freely rotating in the end wall 25 of the drum

2. The outlet end of the pipe 30 is installed in the rotary head 43, which rotates at a speed different from the speed of the drum 2. Thus, gas bubbles are formed in the outlet end of the head 51 and the outlet end of the housing 1, so that the liquid is injected from the nozzles 44 into the gas.

The device in FIG. 4 is similar to the device shown in FIG. 3, except that the gas released by the siphon tube 30 passes through the channel 54 and is discharged through the cylindrical channel 55 between the housing 1 and the discharge side 56 of the head 43. The liquid released through the holes 24 in the end wall 25 of the drum 2 passes through the channel 57 at the rear end of the housing 1 into the channels 39 and 40, and then through the brake assembly 42 and the head 43 enters the nozzle 44.

In accordance with FIG. 5 another embodiment of a rotary device for hydraulic drilling includes all elements of the device shown in FIG. 3, except that the conical rear section 18 of the rotor 9 and the brake assembly 42 are missing, and instead of the cylindrical end wall 25 of the drum there is an end wall having a conical inlet section or a front end 36.

In addition, in the device shown in FIG. 5, the head 43 is rotatably mounted at the rear end of the housing 1. Liquid is discharged through the channels 38 and 40 and through the inclined nozzles 44 at the rear end of the head 43. Gas is discharged through the end wall 25 of the drum 2 through the siphon pipe 30, the channel 58 at the rear end heads 43 and inclined nozzles 59. The rear end of the siphon pipe 30 has a constriction 60. The axes of the nozzles 44 and 59 intersect outside the head 43 so that the liquid jets are surrounded by a stream of gas.

The device shown in FIG. 6, is used to pass through rock 60. This device is similar to that shown in FIG. 4, except that the rotor 9 is cylindrical without a conical rear section, the rear end wall 25 of the drum 2 has a conical front section 36, and there is no brake assembly 42. The liquid is discharged through the openings 24 in the end wall 25 of the drum, the channel 57 at the rear end of the housing 1, the central channel 40 in the head 43 and through the opening 44. The gas channel 54 forming the siphon pipe has a constriction 62.

In accordance with FIG. 7, another embodiment of a combined separator device for hydraulic drilling comprises a separator including a housing 1 with inlet and outlet

- 4 009894 sections, respectively, 64, 65 with internal thread, designed to mate with couplings 67 and 68, respectively. The stator 70 is fixed at the input end 64 of the housing 1. As shown in FIG. 9, the stator 70 includes a cylindrical body 71 with a generally hemispherical front end 72. Curved blades 74 extending outwardly from the body 71 connect the stator to the sleeve 75, which connects the stator to the body 1.

The cylindrical rotor 77 is mounted for rotation on a bearing 78 at the rear end of the stator. The rotor 77 (Fig. 10) contains a cylindrical body 80 with radial blades 81.

The end wall 25 of the drum 2 is rotatably mounted on a bearing 14 located at the inlet end of the sleeve 83 on the siphon pipe 30. The bearing 14 is connected to the input end of the coupling 68 by the sleeve 84. The output end of the coupling 68 is connected to the second body 85 having a speed regulator 87. The regulator 87 contains located in the center of the tubular shaft 88, which is mounted for rotation on the bearings 89 in the coupling 68 and on the bearings 91 located in the coupling 92. The centralizers 93 in the shaft 88 center the siphon tube 30 in the speed regulator. Segmented weights 94 around the shaft 88 regulate the speed of rotation of the shaft, moving outward relative to the housing 85.

The hydraulic drilling assembly, generally designated 96, is rotatably mounted at the end of the coupling 92 using bearings 97, 98, 99, 100 and 101. The assembly 96 includes a housing 102 carrying a rotating head 43. The bearing 97 has an orifice 104, which communicates with the rotating head 43 and forms a mechanical mechanical seal with a bearing 98. The bearing 100 is fixed to the rotating head 43 and forms a mechanical mechanical seal with a bearing 101. The diameters of the contact surfaces of the bearings are chosen such as to minimize mechanically contact load on face seals, while maintaining effective sealing at high pressures.

The liquid discharged from the drum 2 through the holes 24 in the end wall 25 passes through three jet nozzles 106 (only one is shown) in the cover 107 on the rotating head 43. The gas released from the drum 2 passes through the siphon pipe 30 and is discharged through the gas hole 109 at the end of the siphon pipe 30 and through the three outlets 110 (only one is shown) in the lid 107, with the formation of a gas envelope around the liquid stream.

Claims (13)

1. Device for separating gas from liquid under pressure, containing a tubular housing having an inlet and outlet ends, a stator located at the inlet end of the housing and designed to twist the gas-containing fluid supplied to the inlet end of the housing, a drum mounted for rotation in the specified housing behind the stator in the direction of fluid flow between the inlet and outlet ends of the housing, a rotor located at the inlet end of the drum and used to bring the drum into rotation in the housing, the end wall, located at the rear end of the drum in the direction of fluid flow through the housing, fluid outlet openings located at the edges of the end wall and designed to discharge fluid from the drum, a gas outlet located in the center of the end wall and designed to discharge gas from the drum, exhaust a fluid channel located in the housing and used to receive fluid from the fluid outlet and subsequently discharging fluid from the housing, a gas outlet located in the housing and In order to receive gas from the gas outlet and the subsequent gas outlet from the housing, a first flow restriction element located in the liquid outlet and intended to narrow the liquid flow during its discharge from the device, and a second flow restriction element located in the exhaust channel for gas and designed to narrow the flow of gas during its release from the device. 2. The device according to claim 1, in which the rotor contains blades extending in the longitudinal direction of the housing and the drum and designed to direct the liquid containing gas in the longitudinal direction of the drum. 3. The device according to claim 1, containing a hydraulic drilling unit located in the housing behind its output end and having said first flow restriction element. 4. The device according to claim 3, in which the first element of the narrowing of the flow is a nozzle located in the site of hydraulic drilling and designed to release a jet of fluid from the device. 5. The device according to claim 4, in which the second element of the restriction of the flow is constricted from - 5 009894 hole located in the specified node hydraulic drilling and designed to release gas from the device. 6. The device according to claim 5, in which the longitudinal axis of the specified nozzle and the narrowed hole intersect outside the site of hydraulic drilling with the possibility of the formation of a gas shell around the specified stream of fluid. 7. The device according to claim 1, containing a head for hydraulic drilling, mounted to rotate in the housing behind the specified end wall and designed to introduce liquid and gas into it; a Central channel located in the specified head and designed to receive fluid from the specified holes for the release of fluid; inclined fluid openings located in said head and for discharging liquid from the head, whereby the head is rotated in the housing; a siphon pipe forming said gas outlet and passing through said central channel; constriction in a siphon pipe near its outlet end and inclined nozzles for discharging gas located in said head and intended for discharging gas from the head so as to intersect with the liquid exiting said inclined openings for liquid. 8. The device according to claim 7, in which the longitudinal axis of the indicated holes for liquid and gas intersect outside the housing with the possibility of the formation of a gas shell around the liquid emerging from the specified inclined holes for the liquid. 9. The device according to claim 8, having a speed controller mounted to rotate in the specified housing between the end wall and the head, holding the head in the housing and adjusting its rotation speed. 10. The device according to claim 1, in which the end wall of the drum has a conical section extending in front relative to the direction of movement of the liquid and gas in the housing, to ensure smooth flow of fluid to the holes for the release of fluid. 11. A method of hydraulic drilling, comprising the steps of passing a two-phase fluid flow through a hydraulic drilling apparatus, separating gas from a two-phase fluid flow, and thereby forming a gas-enriched phase and a liquid phase in which the gas content is less than 1% by volume. 12. The method according to claim 11, in which the gas-enriched phase and the liquid phase are discharged from the specified device, while the gas-enriched phase surrounds the discharged stream of the liquid phase. 13. The method of injecting a two-phase fluid containing gas and liquid into the wellbore and separating the gas phase from the liquid phase, as a result of which the resulting liquid phase has a gas content of less than 1% by volume.