CN219299244U

CN219299244U - Well backwashing device and well cleanable packer

Info

Publication number: CN219299244U
Application number: CN202320311520.9U
Authority: CN
Inventors: 石爱华; 王建华; 赵效锋; 李英; 刘华杰; 李树林
Original assignee: China Petroleum and Chemical Corp
Current assignee: China Petroleum and Chemical Corp
Priority date: 2023-02-24
Filing date: 2023-02-24
Publication date: 2023-07-04
Anticipated expiration: 2033-02-24

Abstract

The utility model belongs to the technical field of water injection in oil extraction engineering, and particularly relates to a well backwashing device and a well cleanable packer. The back flushing device comprises a back flushing channel, a liquid inlet of the back flushing channel is hermetically provided with a back flushing piston for opening or closing the liquid inlet, the liquid inlet is radially arranged on the outer wall of the device body along the device body, the back flushing piston is slidably sleeved on the outer wall of the device body and is provided with an upper sealing structure and a lower sealing structure which are respectively positioned on the upper side and the lower side of the liquid inlet, the lower sealing structure is provided with a blocking structure, a set sealing redundancy section is arranged between the upper end face of the lower sealing structure and the lower side of the liquid inlet when the lower sealing structure is blocked, and the minimum value and the maximum value of the length of the sealing redundancy section are the difference value between the distance from the upper end face of the lower sealing structure to the lower end face of the lower sealing structure and the diameter of the liquid inlet. The utility model can still ensure that the backwash piston is reset in place and effectively seal the liquid inlet of the backwash channel when sediment is pushed and accumulated at the liquid inlet.

Description

Well backwashing device and well cleanable packer

Technical Field

The utility model belongs to the technical field of water injection in oil extraction engineering, and particularly relates to a well backwashing device and a well cleanable packer.

Background

In the production working process of a water injection well, separate-layer water injection is often required to be realized by adopting a packer, and in order to ensure that a downhole water injection pipe column can continuously work for a long time, the packer capable of flushing the well is required to be used, and the packer capable of flushing the well has the function of back flushing the well.

Chinese patent publication number CN2858936Y, publication date 2007, 1 month 17, discloses a packer for water flooding in separate layers. The device comprises a backwash valve sleeve, a backwash piston, a piston seat, a piston sleeve, a central pipe and an outer pipe, wherein a strip backwash water outlet is formed in the piston seat, a gap for liquid circulation is reserved between the central pipe and the outer pipe, a backwash water inlet tank is formed in the backwash valve sleeve, and a backwash channel of the packer is formed by the backwash water inlet tank, the backwash water outlet and the gap. An annular cavity is arranged between the backwashing valve sleeve and the piston seat, the lower part of the annular cavity extends downwards, a circle of annular groove is formed below openings of the backwashing water port and the backwashing water inlet groove, the backwashing piston is inserted into the annular groove after being pressed down, and the backwashing channel can be closed by means of sealing fit between a sealing rubber ring arranged on the inner wall of the backwashing piston and the piston seat. However, because the treated groundwater is difficult to fully treat after being pumped out from the bottom layer of the oil field during the back flushing, part of underground sediment is mixed in the water body, so that the sediment can be deposited and deposited in the annular groove at the lower part of the annular groove when the water body or the flushing fluid passes through the annular groove between the back flushing valve sleeve and the piston seat, and the back flushing piston cannot descend in place when the back flushing piston is closed by the upper pressure, so that the sealing rubber ring on the back flushing piston is not tightly closed with the piston seat, effective sealing cannot be formed, and interlayer series flow is easily formed during water injection.

The Chinese patent with the authorized bulletin number of CN203394396U and the authorized bulletin day of 2014, 1 month and 15 days discloses a device capable of automatically closing a packer for backwashing well, wherein an upper joint is in threaded connection with a piston sleeve, and a lower joint is in threaded connection with a central tube. The central tube is provided with a water hole, the piston sleeve is provided with a backwashing channel, and the backwashing piston is arranged between the central tube and the piston sleeve. Sealing elements are arranged between the backwashing piston and the central tube, between the backwashing piston and the piston sleeve, and between the backwashing piston and the upper joint, and between the lower joint and the piston sleeve, and the sealing elements between the backwashing piston and the upper joint are of T-shaped packing sealing structures, and the backwashing piston is inserted into and seals the backwashing channel along the axial direction of the backwashing piston. The double sealing structure of the backwash channel is formed by the T-shaped seal and the bevel seal formed by the front end bevel of the upper joint and the bevel of the backwash piston, so that the sealing effect of the backwash channel with less sediment is ensured. And a return spring is also arranged on the backwashing piston so as to realize automatic return of the backwashing piston after backwashing. The same is because the backwash piston inserts in the annular groove structure between center tube and piston sleeve, consequently after the backwash well is finished, be difficult to completely get rid of when silt, the impurity in the groundwater that is used for the backwash well are more, have silt impurity to deposit the siltation in backwash passageway and backwash piston's sealed terminal surface department along with backwash piston's reduction equally for backwash piston closes inadequately, backwash passageway is stopped up, and then leads to backwash well device sealed failure, water injection production is seriously hindered. Therefore, a well-flushing device with a washable packer is urgently needed, so that the well-flushing device can still effectively seal a backwash channel after well flushing is finished under the condition of more underground sediment.

Disclosure of Invention

The utility model aims to provide a backwashing well device which solves the technical problem that a backwashing well device of a washable well packer in the prior art is difficult to effectively seal a backwashing channel under the working condition of more underground sediment.

The utility model also aims to provide a washable well packer to solve the same technical problems.

In order to achieve the above object, the present utility model provides a backwash well device, comprising:

the utility model provides a backwash well device, includes backwash passageway, backwash passageway's inlet department seals and is equipped with the backwash piston that is used for opening or closing the inlet, the inlet is radially offered on the outer wall of device body along the device body, backwash piston slip-on is on the outer wall of device body to be equipped with the last seal structure and the lower seal structure that are located the inlet upper and lower both sides respectively, lower seal structure is equipped with keeps off the structure, is equipped with the sealed redundant section of settlement between its up end and the downside of inlet when lower seal structure is kept off, the minimum of sealed redundant section length is 0, maximum is the difference between the distance of the up end of lower seal structure and the inlet diameter of lower seal structure's lower terminal surface.

The beneficial effects are that: the utility model is characterized in that a liquid inlet is formed in the outer wall of the backwashing well device along the radial direction, a backwashing piston is hermetically and slidably sleeved at the liquid inlet on the outer wall of the backwashing well device, and an upper sealing structure and a lower sealing structure of the backwashing piston are arranged on the upper side and the lower side of the liquid inlet, so that the liquid inlet and the backwashing piston are positioned on the outer side of the backwashing well device, and the moving direction of the backwashing piston is vertical to the arrangement direction of the liquid inlet. Therefore, the silt deposited at the liquid inlet during back flushing can be directly scraped and pushed to the annular space of the oil sleeve by utilizing the sealing sliding of the back flushing piston on the outer wall of the back flushing device, and a sealing structure which is positioned at the end part of the liquid inlet and is perpendicular to the arrangement direction of the liquid inlet is formed at the liquid inlet, so that the back flushing piston is prevented from axially moving along the liquid inlet and pushing the silt into a back flushing channel, and the silt deposited at the sealing part of the end part of the back flushing piston can cause the back flushing piston to be closed untight and then be in sealing failure. Meanwhile, a stop structure is arranged on the lower sealing structure, a sealing redundancy section is formed, sufficient redundancy length is provided for resetting of the backwashing piston, and water injection production is blocked by further avoiding that sediment blocks the backwashing channel and then the backwashing well device fails even if sediment is pushed and accumulated at the stop structure.

As a further improvement, an upper sealing surface corresponding to the upper sealing structure and a lower sealing surface corresponding to the lower sealing structure are arranged on the outer wall of the device body, and the diameters of the upper sealing surface and the lower sealing surface are smaller than the whole diameter of the device body.

The beneficial effects are that: the device body is provided with the upper sealing surface corresponding to the upper sealing structure and the lower sealing surface corresponding to the lower sealing structure, so that the structure of the device body is more compact, the sealing structure of the backwashing piston is convenient to be assembled with the sealing sleeve between the device body, and meanwhile, the external dimension of the backwashing piston can be reasonably designed, so that the overall dimension of the backwashing well device is more compact and consistent with that of the whole washable well packer.

As a further improvement, the diameter of the upper sealing surface is not smaller than that of the lower sealing surface, and the liquid inlet is positioned on the lower sealing surface.

The beneficial effects are that: the diameter of the upper sealing surface is larger than or equal to that of the lower sealing surface, and the liquid inlet is arranged on the lower sealing surface, so that a hydraulic chamber can be formed between the backwashing piston and the outer wall of the device body, and the sealing and retaining capacity of the backwashing piston is improved by utilizing hydraulic pressure.

As a further improvement, at least two circumferential sealing grooves facing the outer wall of the device body are respectively arranged on the upper sealing structure and the lower sealing structure, and the sealing grooves are used for installing sealing rings.

The beneficial effects are that: at least two sealing grooves are arranged and a sealing ring is arranged, so that effective circumferential sealing can be further provided between the backwashing piston and the outer wall of the device body.

As a further improvement, an elastic return spring is arranged between the upper sealing structure and the outer wall of the device body, and the elastic return spring is used for pushing the backwash piston from the opening position of the liquid inlet to the closing position.

The beneficial effects are that: the elastic reset spring is arranged on the backwashing piston, so that automatic reset of the backwashing piston after the backwashing is finished can be realized, the working efficiency of the backwashing well device is improved, a certain closing and retaining capacity is provided for the backwashing piston, and the sealing performance is better.

As a further improvement, the sealing redundant section takes a value of 10mm.

The beneficial effects are that: the length of the sealing redundant section is set to be 10mm, so that the opening and closing strokes of the backwashing pistons can be shortened on the premise of ensuring that the liquid inlet is effectively sealed, and the working efficiency of the backwashing pistons is improved.

As a further improvement, the stop structure is a radially protruding step surface provided on the outer wall of the device body, the step surface being located below the lower sealing structure.

The beneficial effects are that: the radial protruding step surface is used as a stop structure, so that the processing is convenient, and other original step surfaces on the cleanable well packer can be used as a limit structure, so that the integral back flushing device structure is simplified and compact.

As a further improvement, the step surface is an inclined step surface of which the outer side is far away from the lower sealing structure.

The beneficial effects are that: the inclined step surface is arranged on the outer side of the step surface, which is far away from the end surface of the backwashing piston, so that the backwashing piston is convenient to reset, the backwashing piston is assisted to discharge deposited sediment, sediment accumulation is avoided, and on the other hand, a hydraulic surface is formed at the position, which is better when the backwashing piston is started, so that the starting efficiency is improved.

As a further improvement, the lower end surface area of the lower sealing structure is larger than the upper end surface area of the upper sealing structure.

The beneficial effects are that: the lower end surface area of the lower sealing structure of the backwashing piston is larger than the upper end surface area of the upper sealing structure, so that the backwashing piston can slide from the closing position to the opening position by utilizing the pressure difference between the two ends of the outer part of the backwashing piston, and the switching between the opening position and the closing position of the backwashing piston is simpler and more convenient.

In order to achieve the above purpose, the technical scheme of the washable well packer provided by the utility model is as follows:

the utility model provides a but well flushing packer, includes backwash well device, backwash well device includes backwash passageway, backwash passageway's inlet department seal assembly is used for opening or closing the backwash piston of inlet, the inlet is along radially seting up on the outer wall of device body, backwash piston slip sheet is on the outer wall of device body to be equipped with the upper seal structure and the lower seal structure that are located the inlet upper and lower both sides respectively, lower seal structure is equipped with keeps off the structure, is equipped with the sealed redundant section of settlement between its up end and the downside of inlet when lower seal structure is kept off, the minimum of sealed redundant section length is 0, maximum is the difference between the distance of the up end of lower seal structure and the inlet diameter of the up end of lower seal structure.

The beneficial effects are that: the diameter of the upper sealing surface is larger than or equal to that of the lower sealing surface, and the liquid inlet is arranged on the lower sealing surface, so that a hydraulic chamber can be formed between the backwashing piston and the outer wall of the device body, the sealing and retaining capacity of the backwashing piston is improved by utilizing hydraulic pressure, and limiting and stopping can be performed through a transition stage between the two sealing surfaces when the backwashing piston is in an opening position.

As a further improvement, the sealing redundant section takes a value of 10mm.

Drawings

FIG. 1 is a schematic view of the overall structure of a washable well packer of the present utility model with a backwash piston in a closed position;

FIG. 2 is a schematic view of a partially enlarged backwash well device at the washable well packer A shown in FIG. 1.

Reference numerals illustrate:

1. a backwashing well device; 11. an upper joint; 12. an inner center tube; 13. a well washing sleeve; 131. a first reduced diameter section; 132. a second reduced diameter section; 133. a liquid inlet; 14. a cylindrical spring; 15. backwashing the piston; 16. an outer center tube; 161. deblocking the shear pins; 162. a liquid outlet; 2. a rubber cylinder and a spacing ring; 3. a locking mechanism; 4. and a setting mechanism.

Detailed Description

The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the particular embodiments described herein are illustrative only and are not intended to limit the utility model, i.e., the embodiments described are merely some, but not all, of the embodiments of the utility model. The components of the embodiments of the present utility model generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

The present utility model is described in further detail below with reference to examples.

Specific example 1 of a backwash well device provided by the present utility model:

the washable well packer using the backwashing well device provided by the embodiment is shown in fig. 1, and is composed of a backwashing well device 1, a rubber barrel and a spacer ring 2, a locking mechanism 3 and a setting mechanism 4 which are sequentially connected, wherein the corresponding structures of the rubber barrel and the spacer ring 2, the locking mechanism 3 and the setting mechanism 4 are the same as those of the existing packer at present, and the specific description is omitted here.

As shown in fig. 2, the backwashing well device 1 provided in this embodiment includes an upper joint 11, wherein an inner central pipe 12 is screwed on the inner side of the upper joint 11, and the outer side of the upper joint is screwed on the upper end of a well washing sleeve 13. The well casing 13 adopts a stepped structure with a diameter reduced from top to bottom, and the stepped structure is provided with a first diameter reduced section 131 forming an upper sealing surface and a second diameter reduced section 132 which is smaller than the first diameter reduced section 131 and forms a second sealing surface. A liquid inlet 133 is further formed on the lower sealing surface of the second reducing section 132 along the radial direction of the washable well packer, the liquid inlet 133 is further communicated with the upper half part of a well-flushing channel formed by an overflow annular gap between the inner central tube 12 and the well-flushing sleeve 13, the lower half part of the well-flushing channel is formed by the overflow annular gap between the outer central tube 16 and the inner central tube 12 fixedly connected with the well-flushing sleeve 13 through the unsealing shear pins 161, and the lower end of the well-flushing channel is communicated with the outside through a liquid outlet 162.

In this embodiment, the outer side of the well washing sleeve 13 is sealed and slidably sleeved with a backwash piston 15, the structure of the backwash piston 15 is matched with the first reducing section 131 and the second reducing section 132 of the well washing sleeve 13, an upper sealing structure matched with the upper sealing surface and a lower sealing structure matched with the lower sealing surface are provided, and the backwash piston 15 can slide up and down along the axial direction of the well washing sleeve 13 on the liquid inlet 133, so that the liquid inlet 133 and a well washing channel are closed and opened, wherein the backwash piston 15 moves upwards to avoid the liquid inlet 133 until reaching an opening position when stopping with the second reducing section 132, and therefore the backwash piston 15 can be stopped up by a step on the second reducing section 132. The backwash piston 15 moves down to close the liquid inlet 133 until reaching the closing position when stopping with the step surface of the outer central tube 16, so the step surface at the upper end of the outer central tube 16 can stop the backwash piston 15, the step surface is used as a stopping structure of the backwash piston 15, a sealing redundancy section can be formed between the upper end surface of the lower sealing structure at the lower part of the backwash piston 15 and the lower side of the liquid inlet 133 by arranging the step surface, the value of the sealing redundancy section length is minimum 0, the maximum value is the difference between the distance from the upper end surface of the lower sealing structure to the lower end surface of the upper sealing structure and the diameter of the liquid inlet 133, and the difference is preferably 10mm in the embodiment, thereby effectively ensuring the sealing effect on the liquid inlet after the backwash piston 15 is reset, shortening the opening and closing stroke of the backwash piston 15 and improving the working efficiency.

According to the utility model, the liquid inlet 133 is formed on the outer wall of the well flushing sleeve 13 along the radial direction of the well flushing device 1, and the backwashing piston 15 is hermetically and slidably sleeved at the liquid inlet 133, so that the liquid inlet 133 and the backwashing piston 15 form an open structure positioned at the outer side of the well flushing device 1, and meanwhile, the moving direction of the backwashing piston 15 is perpendicular to the arrangement direction of the liquid inlet 133 and positioned at the outer side of the liquid inlet, so that sediment deposited at the liquid inlet 133 can be directly scraped and pushed to the annular space of the oil sleeve when the backwashing piston 15 slides, the sediment is prevented from being pushed into a backwashing channel by the backwashing piston 15, and the phenomenon that the backwashing piston 15 is not tightly closed due to the deposition of the sediment at the end sealing position of the backwashing piston 15 is avoided.

In this embodiment, a cylindrical spring 14 is sleeved between the upper end of the backwash piston 15 and the first reducing section 131, and the backwash piston 15 can be automatically reset to the closing position from the opening position by using the cylindrical spring 14, and a certain closing holding capacity is provided for the backwash piston 15 in the closing position, meanwhile, a hydraulic chamber is formed between the backwash piston 15 and the liquid inlet 133 through respective avoiding structures, and the hydraulic chamber can further ensure the holding effect of the backwash piston 15 in the closing position. Two sealing grooves for installing sealing rings are respectively arranged at the upper end and the lower end of the backwashing piston 15, so that effective circumferential sealing can be further provided between the backwashing piston and the outer wall of the device body.

In this embodiment, the area of the lower end surface of the lower sealing structure of the backwash piston 15 is set to be larger than the area of the upper end surface of the upper sealing structure of the backwash piston, so that the backwash piston 15 can be pushed to the opening position by better utilizing the pressure difference between the hydraulic environment outside the backwash well device 1 and the upper end and the lower end of the backwash piston 15. Meanwhile, the upper end step surface of the outer central tube 16 which is limited by blocking the lower end surface of the backwashing piston 15 is set to be an inclined step surface of which the outer side is far away from the backwashing piston 15, so that on one hand, the backwashing piston 15 is convenient to discharge deposited sediment when the backwashing piston 15 is reset, sediment accumulation is avoided, and on the other hand, the hydraulic environment outside the backwashing well device 1 can be better enabled to form a hydraulic contact surface at the position when the backwashing piston 15 is started, and therefore the starting efficiency of the backwashing piston 15 is improved.

When the washable well packer specifically works, the washable well packer is connected in an oil pipe according to design requirements and is lowered to a downhole setting position along with a water injection string.

When the washable well packer is set, the oil pipe can be pressed, so that the packer can be compressed and expanded through the setting mechanism 4 to be set with the packing element and the spacer ring 2, and then the synchronous locking mechanism 3 is used for realizing synchronous locking, at the moment, the lower end face of the backwashing piston 15 is abutted against the step face of the upper end face of the outer central pipe 16 under the action of the cylindrical spring 14, the liquid inlet 133 of the backwashing channel is sealed and closed, and the closing and retaining effects are provided by the hydraulic chamber between the backwashing piston 15 and the liquid inlet 133.

When the washable well packer is filled with water, the backwash piston 15 is pressed against the upper end step surface of the outer central tube 16 by the hydraulic pressure in the backwash channel, so that the sealing effect of the liquid inlet 133 of the backwash channel is always maintained.

When the washable well packer is used for back flushing, as the liquid pressure of the casing is continuously increased until the liquid pressure is higher than the internal pressure of the oil pipe by 3-5MPa, the pressure of the lower end face of the back flushing piston 15 is enough to push the back flushing piston 15 to slide upwards, at the moment, the back flushing piston 15 moves upwards until the back flushing piston is blocked by the second reducing section 132 and opens the liquid inlet 133, so that the well flushing liquid enters a back flushing channel from the liquid inlet 133 and then flows out from the liquid outlet 162 to enter an oil sleeve annulus, and enters the oil pipe again through a sieve tube, a ball seat and the like at the bottom of the pipe column and then is discharged, and the back flushing is realized.

After the backwashing is finished, the sleeve pressure is smaller than the oil pipe pressure, the upper end face of the backwashing piston 15 is reset downwards under the action of the elastic force of the cylindrical spring 14, and in the resetting process, the backwashing piston 15 scrapes and pushes sediment deposited on the outer side face of the well washing sleeve 13 into an oil sleeve annulus until the lower end face of the backwashing piston 15 is blocked with the upper end step face of the outer central pipe 16. Because the sealing direction of the backwash piston 15 and the moving scraping direction are perpendicular to the arrangement direction of the liquid inlet 133, sediment is not pushed into the backwash channel, even if part of sediment is pushed to the upper end face of the outer central tube 16, the sealing effect of the backwash piston 15 on the liquid inlet 133 is not influenced by the part of sediment, so that the backwash piston 15 can be effectively closed on the backwash channel after well flushing is finished, and the condition that the sediment is not tightly closed due to the accumulation of the sediment at the sealing position of the end part of the backwash piston 15 is avoided, and then the packer is invalid.

When the washable well packer is unpacked, the upper joint 11 is required to be lifted, when the lifting force tonnage reaches 40KN, the packing element and the spacer ring 2 are set, and the friction force between the packing element and the casing is large, so that the unpacking shear pin 161 between the well washing sleeve 13 and the outer central pipe 16 is sheared off, and then the upper joint 11 can be integrally lifted up through the well washing sleeve 13, the inner central pipe 12 and the like, so that the packer is unpacked, and finally a tubular column is pulled out.

Specific example 2 of a backwash well device provided by the present utility model:

in embodiment 1 of the back flushing device of the present utility model, an upper sealing surface corresponding to the upper sealing structure and a lower sealing surface corresponding to the lower sealing structure are provided on the outer wall of the device body, and the diameters of the upper sealing surface and the lower sealing surface are smaller than the overall diameter of the device body. In this embodiment, only one sealing surface may be provided to cooperate with the backwash piston.

Specific example 3 of the backwashing well device provided by the utility model:

in example 1 of the backflushing apparatus of the present utility model, the upper seal surface diameter is smaller than the lower seal surface diameter, and the fluid inlet 133 is located on the lower seal surface. In this embodiment, the upper sealing surface may have a smaller diameter than the lower sealing surface, and the liquid inlet 133 may be provided on the upper sealing surface.

Specific example 4 of the backwashing well device provided by the utility model:

in embodiment 1 of the back flushing device of the present utility model, at least two circumferential sealing grooves facing the outer wall of the device body are respectively provided on the upper sealing structure and the lower sealing structure, and the sealing grooves are used for installing sealing rings. In this embodiment, only one seal groove may be provided, or two or more seal grooves may be provided to enhance the sealing effect, if the sealing conditions allow.

Specific example 5 of the backwashing well device provided by the utility model:

in embodiment 1 of the back flushing device of the present utility model, an elastic return spring is installed between the upper sealing structure and the outer wall of the device body, and the elastic return spring is used for pushing the backwash piston 15 from the open position to the closed position of the liquid inlet 133. In this embodiment, an elastic return spring may be additionally installed in the sealing chamber between the lower sealing structure and the device body.

Specific example 6 of the backwashing well device provided by the utility model:

in example 1 of the backflushing apparatus of the present utility model, the seal redundant segment takes a value of 10mm. In the present embodiment, the value of the seal redundant segment may be set to 15mm or any other value within a set range.

Specific example 7 of a backwash well device provided by the present utility model:

in embodiment 1 of the back flushing device of the present utility model, the stop structure is a radially protruding step surface provided on the outer wall of the device body, the step surface being located below the lower seal structure. In this embodiment, other structures may be provided, such as a blocking structure for the closed position of the backwash piston 15, a radial convex ring for the closed position, or an inclined conical surface.

Specific example 8 of a backwash well device provided by the present utility model:

in example 1 of the back flushing device of the present utility model, the step surface is an inclined step surface having an outer side remote from the lower seal structure. In this embodiment, the step surface is not an inclined step surface, but the radial dimension of the step surface is correspondingly reduced, so that the step surface can be stopped with the backwash piston 15, and the hydraulic contact area of the backwash piston 15 is reserved to facilitate the backwash piston 15 to move upwards.

Specific example 9 of a backwash well device provided by the present utility model:

in example 1 of the backflushing apparatus of the present utility model, the lower end surface area of the lower seal structure is greater than the upper end surface area of the upper seal structure. In this embodiment, the outer surface shape of the backwash piston 15 may be appropriately adjusted so that the total area of the side facing the closed position is larger than the total area of the side facing the open position.

Embodiments of washable well packers in the present utility model:

examples of the washable well packer include those described in any one of examples 1 to 9 of the above-described backwashing well device, and will not be described in detail herein.

It should be noted that the above-mentioned embodiments are merely preferred embodiments of the present utility model, and the present utility model is not limited to the above-mentioned embodiments, but may be modified without inventive effort or equivalent substitution of some of the technical features thereof by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims

1. The utility model provides a backwash well device, includes backwash passageway, backwash passageway's inlet department seals and is equipped with the backwash piston that is used for opening or closing the inlet, characterized by, the inlet is radially seted up on the outer wall of device body along the device body, backwash piston slip-on is on the outer wall of device body to be equipped with the upper seal structure and the lower seal structure that are located the inlet upper and lower both sides respectively, lower seal structure is equipped with the structure that keeps off, is equipped with the sealed redundant section of settlement between its up end and the downside of inlet when lower seal structure is kept off, the minimum of sealed redundant section length is 0, maximum value is the difference between the distance of the up end of lower seal structure and the inlet diameter of lower seal structure's up end.

2. The apparatus according to claim 1, wherein an upper sealing surface corresponding to the upper sealing structure and a lower sealing surface corresponding to the lower sealing structure are provided on an outer wall of the apparatus body, and diameters of the upper sealing surface and the lower sealing surface are smaller than an overall diameter of the apparatus body.

3. The apparatus of claim 2 wherein the upper sealing surface has a diameter not less than the diameter of the lower sealing surface and the inlet is located on the lower sealing surface.

4. The apparatus of claim 3, wherein the upper and lower sealing structures are respectively provided with at least two circumferential sealing grooves facing the outer wall of the apparatus body, and the sealing grooves are used for installing sealing rings.

5. The apparatus of claim 1, wherein an elastic return spring is installed between the upper sealing structure and the outer wall of the apparatus body, and the elastic return spring is used for pushing the backwash piston from the open position to the closed position of the liquid inlet.

6. The apparatus of any one of claims 1 to 5 wherein the seal redundant segment has a value of 10mm.

7. The apparatus of claim 6, wherein the stop structure is a radially protruding step surface provided on an outer wall of the apparatus body, the step surface being located below the lower seal structure.

8. The apparatus of claim 7, wherein the step surface is an inclined step surface that is outwardly remote from the lower seal structure.

9. The apparatus of claim 8, wherein the lower seal has a lower face area that is larger than an upper face area of the upper seal.

10. A washable well packer comprising a well backwash device, wherein the well backwash device is a well backwash device according to any one of claims 1 to 9.