RU2376455C2 - Method of chemical reagent impulsive implosion bottom hole treatment, equipment for its execution, pressure impulse generator - Google Patents

Abstract

FIELD: oil-and-gas production.

SUBSTANCE: invention related to oil-and-gas production, can be used for bottom hole zone - BHZ cleaning out of calmative materials, including deposits of asphalts, resins, and paraffins - DARP, also for repair BHZ collector properties during wells development, recovery efficiency increase, including production wells in complicated geophysical conditions. Method of chemical reagent impulsive implosion bottom hole zone - BHZ treatment, which includes pumping into BHZ active reagent fluid media through hole clearance, overflushing, process ageing until deposits of asphalts, resins, and paraffins - DARP dissolved, other calmative deposits and withdrawal of generated passive media, then pump in active media - hydrocarbon dissolver with adding of 0.05-0.1 wt % SAS during depressive-repressive treatment, then overflush the media with killing fluid in volume not less than 1 m³/ m per perforation interval, ageing and further passive media withdrawal, final depressive-repressive-impulse BHZ treatment with pumping into hole clearance killing fluid as a active media with adding 0.1 -2.0 wt % of water-repellent SAS for production well and hydrophilic SAS for injection well. Pressure impulse generator - PID, consists of a case equipped with barrel and a top cap, which has access canal with ability to create a vacuum chamber when connected to TS, inside the canal there is a slide valve locate in a such a way that it can be connect to barrel through its conical surface, which is spring-loaded, installed on remote barrel with a backward moving string, springing it from the opposite side with a block of disk springs and contact of its back side with a piston of the slide valve reverse time delay mechanism, which consists of combined with a returned valve choke with ability to provide liquid flow through cavity formed by filter and shell with radial holes and pass via case radial canals into vacuum chamber, slide valve reverse time delay mechanism connected with the case via barrel. Equipment for chemical reagent impulsive implosion BHZ treatment, includes TS and serially installed swabbing device, parker and PID wich radial canals located on the same level as bottom perforation holes of stratum perforation interval.

EFFECT: increase of oil and gas wells production, well injection capacity increase for injection wells, bottom hole zone recovery and productivity factor and initial permeability increase, noncoherent water withdrawal, water-oil emulsion breaking down.

3 cl, 2 dwg

Description

The invention relates to the oil industry and can be used to clean the bottom of the formation — the bottomhole formation zone from clogging materials, including the removal of asphalt-resin-paraffin deposits — paraffin deposits, and also to restore the reservoir properties of the bottomhole formation zone during development, resuscitation and increase of productivity of wells, including those operated in complicated geological and physical conditions.

A known method of restoring the reservoir properties of the formation in the near-wellbore-well zone when exposed to cyclic depressions using jet devices, the principle of operation of which is based on the exchange of energy between two flows with different pressures and the formation of a mixed stream with intermediate pressure. The mixed streams can be in either a gas or liquid state, or can be a mixture of gas, liquid and solid particles, such as sand. With the help of these devices it is possible to create large depressions on the formation and transport the formation fluid from deep wells. Depending on the design parameters of the jet pump, the volumetric masses of the liquid in the tubing - tubing and annulus, it is possible to achieve a decrease in pressure in the BCP and subsequent restoration of hydrostatic pressure within 3-5 minutes. It is recommended to use jet pumps when developing wells after drilling is completed, when operating wells in order to increase their production rates, and also to increase the injectivity of injection wells [1].

Common disadvantages of the use of this equipment are the requirements for well pretreatment in order to cause inflow or increase the permeability of the bottomhole formation zone of injection wells, the difficulty of providing the process with high-performance pumping equipment and significant volumes of pumping fluids, as well as the problem of their subsequent disposal.

In addition, for the current well stock, the problem of ensuring the strength and tightness of cement stone to prevent breakthroughs of water from interbeds, as well as the difficulty in assessing the effect of depression values, their exposure time and the number of cycles for different types of reservoirs, is no less acute. Also, when using jet pumps, it is almost impossible to provide predetermined levels of depression per formation.

A known method of creating multiple depression in the interval of the reservoir and a device for its implementation. The essence of the method consists in launching on the tubing a device for oil production and processing of a bottomhole well borehole, consisting of a depression chamber with receiving holes in its upper part and installed in it with the possibility of reciprocating movement of the plunger with a valve. The implosion device is set so that the window of the depression chamber is opposite the interval of the treated formation. Then the well is packaged and then, using the winch of the lifting unit, the plunger is lowered all the way into the lower valve seat. After that, the plunger is raised to a level above the chamber windows, while the valve on the plunger closes and a vacuum is created in the chamber. From the moment the lower end of the plunger reaches the area above the windows, the borehole fluid from the under-packer zone rushes to the lower part of the chamber, creating an instant depression in the bottomhole zone. In this case, the pressure in the bottomhole zone can decrease to atmospheric, since the column of fluid in the annulus of the well is separated by a packer, and the fluid in the tubing is blocked by a plunger. Thus, the fluid from the reservoir under the influence of depression enters the sub-packer zone of the well and into the depression chamber. Then the cycle is repeated as many times as necessary until the process of cleaning the PPP from the products of colmatapia and blocking agents is completed [2].

The specified method provides the ability to create instantaneous and repeatedly repeated depressions on the formation for a single descent of deep equipment without the use of special equipment, it allows immediately after cleaning the bottom-hole zone to pump hydrocarbon solvents or other chemical reagents into the formation and thereby continue the process of processing the well to increase its production rate or throttle response.

However, these known method and device for creating a multiple repetitive implosion effect do not allow the impact on the bottomhole zone using the energy of hydraulic shock, since when it is implemented, it is only possible to create depression on the formation. At the same time, it is known that due to the effect of implosion in the BZP through the annulus, it is possible to create hydraulic shocks with a pressure twice or more than the mountain pressure, which will provide an improvement in the filtration properties of the formation due to the expansion of natural or the formation of new artificial cracks. In addition, the procedure for carrying out technological operations when the first stage is used to clean the bottom-hole zone from clogging agents and plugging agents, and the second stage is used to treat the bottom-hole zone of the well with chemical reagents, is not optimal to achieve the desired end result.

The ideal conditions for the effect of chemical reagents on the bottomhole zone may be their injection with a simultaneous depression-repression-wave load on the bottomhole zone.

A known method of processing the bottom-hole zone of the well, including flushing the well with an AFS solvent, pumping the solvent into the bottom-hole zone of the well and implosion exposure. To treat the bottom-hole zone, a well is selected in the area of the reservoir with reduced reservoir pressure, into which the tubing string is lowered below or to the level of the lower perforation holes of the reservoir.

As a paraffin solvent, a 3-6% solution in an organic solvent of a mixture of heavy pyrolysis resin and diproxamine in the ratio (9:11): 1 is used, the wells are filled with solvent, starting from the lower perforations to the wellhead, after which the first technological exposure for 12-24 hours, the selling of solvent in the PPP is carried out in volumes of 1.5: 2.5 m ³ / m perforation interval, then a second technological exposure is carried out for 12-24 hours.

When exposed to solvent, paraffin deposits are destroyed in the bottomhole zone and in the wellbore. After the end of this operation, the solvent is replaced with a kill fluid and a thermal implosion effect is carried out, as a result of which the dissolved paraffin deposits are removed from the bottomhole zone into the implosion chamber and removed from the well [3].

The known method can only be used for wells in the area of deposits with reduced pressure. At the same time, it is rather laborious, since it requires two technological endurances for 12-24 hours each and at least two round trip operations for tubing and a thermal implant device. In addition, the removal of dissolved paraffin is required in addition to implosion thermal exposure. You should also pay attention to the fact that the removed volume of dissolved paraffin deposits will correspond to the volume of the implosion chamber, which limits the effectiveness of the method when it is used for highly productive wells and wells with dissected reservoirs complicated by paraffin deposits.

It is also known a device for pulse-depressive effects on the PPP, including a tubing string with a pipe in the lower part, a sealing element made in the form of a hollow cylindrical elastic cuff with holes provided with a cylindrical spring on the inside, and mounted on the pipe between the upper and lower movable stops cylindrical body with side openings and a plug in the lower end part, in which a plunger with a valve and a sleeve in of the upper part, placed in the nozzle with the possibility of axial movement, a sealing element is installed on the nozzle, the cylindrical body is concentrically located in a perforated casing rigidly connected to the nozzle. In this case, the perforated casing with the lower muffled end abuts against the artificial bottom of the well, the bushing is connected to the movable stop of the sealing element by means of studs passing through longitudinal windows made on the nozzle. The design of the device provides such a stroke length of the plunger, in which in the extreme upper position, the opening of the side openings of the housing is ensured, which occurs after the sealing sleeve closes the annulus. After creating the maximum possible vacuum in the implosion chamber, the liquid from under the sealing cuff and casing rushes into the rarefied space, while a deep depression pulse occurs at the bottom of the well, causing accelerated fluid movement in the bottomhole zone. After equalizing the fluid pressure under the plunger with the current bottomhole pressure, the sealing collar due to the movement of the sleeve down under the action of the spring decreases in diameter and seals the annulus of the well. The hydraulic pressure of the liquid column above the seal is transmitted to the bottom of the well and creates a pressure impulse, which also propagates in the bottomhole zone of the well. As a result, a depression impulse is first created in the bottomhole zone, and then a pressure impulse, which is again replaced by a depression impulse, etc. Thus, the creation of time-varying depression pulses and pressure pulses causes the appearance of alternating (tensile and compressive) pressure gradients in the bottom-hole zone of the well. This leads to the formation of microcracks in the rocks and provides high-quality cleaning from contamination of the pore space of the bottomhole zone [4].

This device is operated with emphasis on artificial bottom hole, which in some cases is impossible due to the design features of well completion. In addition, the dimensions of the implosion chamber for specific wells are determined by calculation, which cannot be done for this device. It is also known that the effectiveness of the impact on the bottom-hole zone of wells by the implosion method is determined by the amplitude of the pressure increase and its duration, i.e. the shorter the opening time of the implosion chamber, ceteris paribus, the greater the amplitude of the oscillations in the well [5]. Since the hydrostatic shock impulse arising with a decrease in diameter is stretched in time, it will not be effective enough, especially for wells producing highly viscous oils.

The objective of the invention is to increase the productivity of oil and gas condensate wells that are put into operation, increase the injectivity of injection wells, restore and increase the coefficient of productivity and initial permeability of the bottomhole formation zone, remove loosely bound water, destroy the oil-water emulsion by reducing the entrainment of particles of contaminating fluids deep into the reservoir, phased application of chemical reagents with simultaneous exposure to microwave and providing optimal indicators of depression and repression on flippers.

The problem is solved in that in the method of reagent-pulse-implosion treatment of the bottom hole of the formation - PZP, which includes pumping through the annular space of the active reagent liquid medium in the PZP with its pushing into the formation, technological exposure to dissolve asphalt-resin-paraffin deposits, paraffin deposits, and other clogging formations and pumping the resulting passive medium, carry out the injection as the specified active medium of a hydrocarbon solvent with the addition of 0.05-0.1 wt.% surfactant with depression and repression stimulation of the formation, then the injection of this medium with a kill fluid in a volume of not less than 1 m ³ / m of the perforation interval, exposure, removal of the passive medium and the final depressive-repression-pulse action on the bottom hole with injection into the annulus as the indicated active medium of the kill fluid with the addition of 0.05-0.1 wt.% hydrophobizing surfactant for the production well or hydrophilizing surfactant for the injection well.

The problem is also solved by the fact that they use the installation for reagent-pulse-implosion processing of PPP, containing CSTP and sequentially installed on it a swab device, a packer and a depression pulse generator, with the placement of its radial channels at the same level with the lower perforation holes of the formation perforation interval . Moreover, a depressive pulse generator containing a housing provided with a top cover through the sleeve, made with an inlet channel with the possibility of forming a vacuum chamber when connected to the CSTP, in which the spool is placed with the possibility of contact through its conical surface with the sleeve, spring-loaded reverse spring mounted on the remote sleeve , springing it from the opposite side by a disk spring unit and its end contact with the piston of the backward delay time mechanism Single consisting of a combined throttle non-return valve to provide a fluid passage formed through the filter and the housing with radial openings and the cavity through radial passages in the housing a vacuum chamber, and a time delay mechanism backstop valve sleeve connected to the housing.

The essential features are:

- Depression-repression-impulse effect on the bottom-hole zone with the phased effect of kill fluids and solutions of chemical reagents to create depression pulses and repression pulses that are repeatedly repeated and alternating one after another. The creation of alternating impulses causes the appearance of tensile and compressive pressure gradients in the near-well zone of the well, which leads to the formation of microcracks in the rocks;

- destruction of paraffin and dispersion of solid colmatants in the mode of dynamic and static effects of solutions of chemical reagents;

- removal of decomposition products of paraffin paraffin deposits, other clogging contaminants with the realization of a multiple repetitive implosion effect in the under-packer zone due to a device with an instantaneous check valve with a predetermined pressure drop in the annulus and tubing, as well as a mechanism for controlling the time delay of its closure before the end of the wave process;

- depression-repression-impulse effect on the bottom-hole zone of the formation with hydrophobization or hydrophilization of the pore space of the bottomhole formation zone with solutions of chemical calculations.

Figure 1 shows a set of technological equipment, which includes a string of tubing 1, swab 2, packer 3 and, through a set of tubing 4, a depression pulse generator - DGI 5. Moreover, the annular space 6 in the bottom-hole zone can be blocked by a planted packer 3. A drive is installed on the surface — a pump unit 7, which is hydraulically connected to the annulus.

Figure 2 shows a General view of a depressive pulse generator. The device consists of a housing 8, which is equipped with a top cover 10 through a sleeve 9 with an input channel 11 for connecting to a set of tubing, which form a vacuum chamber to the swab piston. The connection of the vacuum chamber with the annulus, and through it with the reservoir medium is carried out through the DGI.

A spool 12 is located in the housing 8 of the DGI, having the possibility of contact through a conical surface with a spring-loaded sleeve 13. On the opposite side, the spool is spring-loaded with a disk spring unit 14. The end part of the spool 12 is in contact with the piston of the spool reverse delay mechanism, which extrudes fluid through the combined throttle with the check valve 15 and the cavity 16, limited by the filter 17 and the casing 18 with radial holes 19.

The pressure level in the vacuum chamber is regulated by tightening the disk spring package 14 with the nut 20, the time delay mechanism is regulated by selecting the parameters of the throttle 15 and the return spring 21. The delay mechanism is fixed by the sleeve 22 to the housing 8.

The principle of operation of the device is to create a swab when lifting the piston, vacuum in the vacuum chamber, while it is possible to drop pressure in it until the formation of vacuum zones and spread them down by an amount controlled by the setting of the disk spring unit. In this case, the spool 12, mating with the sleeve 13 under pressure in the annulus will move up until the moment when the sleeve 13 is at the bottom through the spacer sleeve 23 and at this moment the mating spool 12 and the sleeve 13 will undock. Pressure under the lower end of the sleeve 13 will fall and it will begin to sharply move downward under the action of the spring 21, increasing the inlet window into the vacuum chamber. At the same time, the spool 12 will lower more slowly due to the fact that the time delay mechanism is activated due to the displacement of the fluid through the throttle 15 by the piston 24, which is pushed by the end part of the spool 12. Through radial channels 25 in the housing 8, liquid from the bottomhole enters the vacuum chamber zones, performing an implosive shock in the annulus with the initial rarefaction wave and the subsequent reflected wave of increased pressure, which can be enhanced by the hydrostatic pressure of the liquid column in the annulus a space of.

After the wave process is over, the pressure in all chambers is equalized, under the action of a packet of Belleville springs, the spool 12 returns to its initial position and the cycle repeats again.

SUMMARY OF THE INVENTION

During the operation of oil and gas condensate wells, their productivity gradually decreases, and during the operation of injection wells, their injectivity decreases due to deterioration of reservoir properties in the bottomhole zone.

In the proposed method using the proposed depressive pulse generator and installation containing it, the task of increasing productivity and increasing the injectivity of wells is solved as follows.

A well is selected for processing and killing is carried out with aqueous solutions of complex surfactants - surfactants, aqueous emulsion or petroleum liquids that do not impair the reservoir properties of the PPP.

Then a set of technological equipment is lowered into the well (see figure 1), which includes a tubing string 1, swab 2, packer 3 and, through a set of tubing 4, a depression pulse generator 5. In this case, the annulus 6 in the bottomhole zone can be blocked planted packer 3.

A set of technological equipment is placed in the well so that the radial channels 25 of the depressive pulse generator are at the same level as the lower perforations in the well perforation interval.

At the initial stage of processing in the tubing, when the swab piston is lifted, an implosion - vacuum chamber is formed between it and the depression pulse generator. Upon reaching a predetermined pressure difference in the annulus and the vacuum chamber, ensured by adjusting the compression ratio of the disk spring unit, a depressive pulse generator is activated, performing implosive shocks in the BZP, alternating with the impact of the hydrostatic liquid column in the annulus. At this stage, a depressive and repressive effect on the PZP occurs, in which the technological fluid of killing with a sharply changing direction of flows and their amplitude acts on the pore space of the formation.

With multiple implosion-repression effects on the bottomhole zone, favorable conditions are created for the primary destruction of the paraffin deposits and the separation of the clogging particles from the surface of the perforation channels. In addition, the creation of time-varying depression pulses and pressure pulses causes the appearance of alternating pressure gradients, due to which new microcracks form in the reservoir.

At the next stage, a composition of chemical reagents is pumped through the annulus in a volume of at least 1 m ³ / m of the reservoir to destroy the ARPD and disperse solid colmatants, while maintaining technological exposure for 12-24 hours.

After technological exposure, the packer is brought into working condition, blocking the bottom-hole zone, and fluid selection is started using a swab. Since the annular space of the well is closed, when creating a vacuum, the DGI is turned on and the well fluid from the sub-packer zone rushes into the vacuum chamber, creating an instant depression in the bottomhole zone. The cycle is repeated as many times as necessary until the PPP is completely cleaned of the products of the destruction of the paraffin and the removal of process liquids.

At the last stage, the packer is brought into a transport state and a working fluid with hydrophobizing additives for producing wells or hydrophilizing for injection wells is fed through the annulus, performing the final processing of the bottomhole formation zone in a depression-repression-pulse mode. The processing time is determined based on the absorption volume of the working fluid, at least the previously pumped volume of the composition of chemical reagents.

In this case, solvents - Nefras A-150/200, Nefras AK, a mixture of aromatic and aliphatic solvents of the FLEK brand and others with the addition of surfactants - demulsifiers - Penta 491-M, diproxamine 157-65M, Reopon-IR, etc. The following can be used as a silencing liquid: anhydrous oil from UPN units - oil treatment units - with the addition of demulsifiers, such as Penta 491-M, SNPH, Synterol P, TN-10 and others at a concentration of 0.01-0.1 wt. %, mineral formation water, aqueous solutions of salts, with the addition of complex surfactants, including Neftenol K, Sofexo l IFC, Sinol KAM and others with a concentration of 0.3-4 wt.%. At the stage of hydrophobization of the pore space of the PZP, cationic oil-soluble surfactants - Don-52, Penta-804 and others in a concentration of 0.1-1.0 wt.% Or water-soluble surfactants - Neftenol K, Neftenol GF, IVV- are added to the oil-based killing fluid 1, Catamine AB and others in a concentration of 0.5-1.5 wt.%. For hydrophilization of the pore space of the PPP, killing fluids with the addition of anionic surfactants such as Neftenol NZ, Sulfonol, Sulfonat, Oksifos B and others in a concentration of 0.3-2.0 wt.% Are used.

An example of a specific implementation.

The bottom-hole zone of production well No. 994 is processed at a depth of 1832 m, which uncovered a productive formation 7 m thick at the Sovetskoye field of the Tomskneft oil and gas production department.

The wells are muffled with anhydrous oil with the addition of 0.05 wt.% Demulsifier Penta 491-M, the DGI is adjusted to a predetermined response pressure of the instant opening mechanism of the implosion chamber.

A set of technological equipment consisting of a swab, a packer, DGI is lowered into the well on the tubing and placed in such a way that the radial channels of the DGI are at the same level with the lower perforation holes of the well perforation interval.

Using a swab installation, fluid is removed from the tubing, creating a pressure drop between the tubing and the annulus, at which the DGI valve instantly opens and fluid from the annulus rushes into the tubing, creating a sharp decrease in pressure in the annulus. A deep impulse of depression occurs at the bottom of the well, causing accelerated fluid movement in the near-wellbore zone. After filling the implosion chamber with liquid, the hydrostatic pressure of the liquid column in the annulus creates a repression pressure impulse, which propagates in the bottomhole zone of the well.

The creation of multiple and alternating in time pulses of depression and pressure pulses leads to the destruction of stable emulsions, loosening of paraffin deposits and the formation of microcracks in the rocks of the bottomhole formation zone.

At the same time as pumping out the killing fluid through the tubing, a composition of liquid chemicals is fed into the annulus of the well to remove the paraffin - a Penta-491M hydrocarbon solution at a concentration of 0.1 wt.% In Nefras A-150/200.

After replacing the silencing fluid with the dissolving agents, the ARPD stops swabbing with a depressive and repressive effect on the formation, closes the wellhead, creates the necessary overpressure in the annulus of the well (but not more than the hydraulic fracturing pressure, which approximately corresponds to the rock pressure), and grouts are forced into the PPP kill fluid in a volume of 1.1 m ³ / m perforation interval, after which they carry out technological exposure for 20 hours. Anhydrous oil with the addition of cationic surfactants in an amount of 0.5-1.0 wt.% Is used as a kill fluid at this stage. In this example, 0.5 wt.% Don-52.

After carrying out the technological exposure, the packer is brought into working condition and, using the swabbing unit and the DGI, it is carried out, creating multiple depressive pulses, removing from the BCP the products of the destruction of the paraffin deposits and colmatants. At the last stage, the packer is brought into a transport state and the final depressive-repression-impulse impact on the bottom-hole zone is made with a kill fluid with hydrophobization of the pore space of the bottomhole zone of the producing well.

After the final processing — hydrophobization of the bottomhole formation zone — DGI and packer are removed from the well, the pumping equipment is lowered onto the tubing, and the well is put into operation.

Before the reagent-pulse-implosion treatment of the bottom-hole zone, the production rate of the well was 1.5 tons / day, and after treatment it became 7 tons per day for oil.

The application of the proposed method and installation with DGI for processing the bottomhole formation zone of producing oil, gas condensate and injection wells will allow increasing the productivity of wells at minimal cost.

Information sources

1. Yu.G. Anakovich, R.S. Yaremchuk. Impact on the bottomhole formation zone by multiple depressions. "Oil industry", 1985, No. 4, p. 27-30.

2. Popov A.A. Impact effects on the bottomhole zone of wells. - M: Nedra, 1990, pp. 108-109.

3. RF patent No. 2146329, cl. C1, E21B 42/25. Publ. 2000 year

4. RF patent No. 2177540, cl. C1, E21B 43/25. Publ. 2001 Bull. Number 36.

5. Popov A.A. Impact effects on the bottomhole zone of wells. - M: Nedra, 1990, pp. 78-88.

Claims (3)

1. The method of reagent-pulse-implosion treatment of the bottom-hole zone of the formation — PZP, including the injection of the active reagent liquid medium into the PZP through the annulus with its introduction into the formation, technological shutter speed for dissolving asphalt-resin-paraffin deposits of paraffin and other aggregating formations, and pumping out the formed passive medium, the fact that they carry out the injection as the specified active medium of a hydrocarbon solvent with the addition of 0.05-0.1 wt.% surfactant - surfactant when repeatedly depression - repressionnom influence on the formation, and then - this medium prodavku damping fluid in the amount of at least 1 m ³ / m perforation interval, exposure, removing passive medium and the final depression repressionno--pulsed effect on PPP with pumping into the annulus as said active killing fluid medium with the addition of 0.1-2.0 wt.% hydrophobizing surfactant for the production well or hydrophilizing surfactant for the injection well. 2. Depression pulse generator, comprising a housing provided with a top cover through the sleeve, made with an inlet channel with the possibility of forming a vacuum chamber when connected to the tubing string — CSTP, in which the spool is placed with the possibility of contact through its conical surface with the spring loaded sleeve spring plate mounted on the remote bushing by a disk-shaped spring unit and its end contact with the piston of the back-stroke time delay mechanism of the spool, consisting of a combination of Foot throttle valve with a return to provide a fluid passage formed through the filter and the housing with radial openings and the cavity through the radial passages into the vacuum chamber housing. 3. Installation for reagent-pulse-implosion treatment of the bottom-hole formation zone — PZP, containing CSTP and a swab device, packer and depression pulse generator — DGI sequentially installed on it, characterized in that it contains DGI according to claim 2 with the placement of its radial channels flush with the lower perforations of the formation perforation interval.

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