阅读说明：本技术 充填工具及完井管柱 (Filling tool and well completion string ) 是由 孔洋 武洪鑫 顾海瑞 苏延龙 张玉涛 梁作愿 侯红意 尹玉超 于 2019-11-01 设计创作，主要内容包括：本发明提供了一种充填工具及完井管柱,涉及油井充填的技术领域,充填工具包括中心管、套设于所述中心管外的返液管以及与所述中心管连接的双通管；所述返液管与所述中心管之间留有环空空间,所述返液管上开设有与所述环空空间连通的返液孔；所述返液管的一端与所述中心管的一端密封连接,所述返液管的另一端与所述双通管外壁密封连接,所述中心管的另一端与所述双通管内壁密封连接；所述双通管上开设有与所述中心管连通的通孔,所述双通管管壁内开设有与所述环空空间连通的返液通道；所述双通管内设置有用于封堵所述双通管的密封部,所述通孔位于所述密封部与所述中心管之间。完井管柱包括充填工具。达到了充填方便的技术效果。(The invention provides a filling tool and a well completion pipe string, and relates to the technical field of oil well filling, wherein the filling tool comprises a central pipe, a liquid return pipe sleeved outside the central pipe and a double-way pipe connected with the central pipe; an annular space is reserved between the liquid return pipe and the central pipe, and a liquid return hole communicated with the annular space is formed in the liquid return pipe; one end of the liquid return pipe is hermetically connected with one end of the central pipe, the other end of the liquid return pipe is hermetically connected with the outer wall of the double-pass pipe, and the other end of the central pipe is hermetically connected with the inner wall of the double-pass pipe; a through hole communicated with the central pipe is formed in the double-way pipe, and a liquid return channel communicated with the annular space is formed in the pipe wall of the double-way pipe; be provided with in the bi-pass pipe and be used for the shutoff the sealing of bi-pass pipe, the through-hole is located the sealing with between the center tube. The completion string includes a packing tool. The technical effect of convenient filling is achieved.)

1. A filling tool, comprising: the liquid return pipe comprises a central pipe (100), a liquid return pipe (200) sleeved outside the central pipe (100) and a double-way pipe (300) connected with the central pipe (100);

an annular space (110) is reserved between the liquid return pipe (200) and the central pipe (100), and a liquid return hole (210) communicated with the annular space (110) is formed in the liquid return pipe (200);

one end of the liquid return pipe (200) is connected with one end of the central pipe (100) in a sealing manner, the other end of the liquid return pipe (200) is connected with the outer wall of the double-way pipe (300) in a sealing manner, and the other end of the central pipe (100) is connected with the inner wall of the double-way pipe (300) in a sealing manner;

a through hole (310) communicated with the central pipe (100) is formed in the double-way pipe (300), and a liquid return channel (320) communicated with the annular space (110) is formed in the pipe wall of the double-way pipe (300);

a sealing part (340) used for sealing the double-way pipe (300) is arranged in the double-way pipe (300), and the through hole (310) is located between the sealing part (340) and the central pipe (100).

2. The filling tool according to claim 1, wherein the number of the through holes (310) is plural, a liquid discharge sleeve (400) is sleeved in the double-way pipe (300), the liquid discharge sleeve (400) is provided with liquid discharge channels with the same number as the through holes (310), and each liquid discharge channel is communicated with the corresponding through hole (310).

3. Filling tool according to claim 2, wherein each drainage channel comprises a plurality of drainage holes (410), the plurality of drainage holes (410) being evenly distributed along the axis of the double pipe (300) and the aperture of the drainage holes (410) decreasing in the direction away from the central pipe (100).

4. The filling tool according to claim 2, wherein a positioning groove (420) is formed in the drainage sleeve (400), a positioning member (330) adapted to the positioning groove (420) is installed on the two-way tube (300), and the drainage channel can correspond to the through hole (310) by positioning the positioning member (330) and the positioning groove (420).

5. Filling tool according to claim 2, wherein a plurality of through holes (310) are evenly distributed circumferentially along the bi-tube (300).

6. The filling tool according to claim 5, wherein the liquid return channel (320) is provided in a plurality, the liquid return channels (320) are evenly distributed along the circumferential direction of the double-way pipe (300), and the through holes (310) and the liquid return channels (320) are arranged in a staggered manner.

7. Filling tool according to any of claims 1-6, further comprising a connection pipe (500) for connecting to another working string, wherein the end of the bi-pass tube (300) remote from the central tube (100) is sealingly connected to the connection pipe (500).

8. The filling tool according to claim 7, wherein a plurality of sealing members (600) are fixedly sleeved outside the liquid return pipe (200) and the connecting pipe (500);

the liquid return pipe (200) and the connecting pipe (500) are in sliding seal with the filling sliding sleeve through a sealing element (600).

9. Filling tool according to any of claims 1-6, wherein the sealing portion (340) comprises a sealing ball seat and a sealing ball adapted to the ball seat;

the sealing ball seat is connected with the bottom of the double-way pipe (300) in a sealing way.

10. A completion string comprising a packing tool according to any of claims 1 to 9.

Technical Field

The invention relates to the technical field of oil well filling, in particular to a filling tool and a well completion string.

Background

During the flow of crude oil from the formation into the wellbore, some sand may be carried into the wellbore. In order to prevent sand production of an oil well, on one hand, well cementation and completion modes are selected correctly according to oil layers and oil well conditions, reasonable exploitation measures are made, and the management level is improved; on the other hand, corresponding sand control methods are adopted according to specific conditions of oil layers, oil wells and sand production. The prior sand control method mainly comprises the methods of mechanical process sand control, chemical sand control, liquid return pipe external expansion type packer sand control, gravel packing sand control and the like.

In the existing gravel packing tools, two modes of fracturing packing and circulating packing are generally adopted. The fracturing filling is to extrude gravels into the stratum to enable the stratum to generate fracture channels, can realize the filling with large discharge capacity and high sand ratio, can realize the aim of stratum reconstruction, improves the fluid seepage state of a near wellbore, reduces the oil extraction resistance and realizes the high yield of an oil well. The circulating filling is to fill gravel into the annular space between the sand control screen pipe and the shaft by using sand carrying liquid, so that the gravel filling layer becomes a sand control barrier, and when stratum liquid flows into the shaft, the carried stratum sand can be blocked outside the gravel filling layer, thereby realizing sand control.

For unconsolidated sandstone formations, a two-step method is generally adopted to complete the well in order to achieve the purposes of improving the formation and improving the yield. The two-step method means that the next operation pipe column is firstly subjected to fracturing filling to reform the stratum, and then the next operation pipe column is subjected to gravel circulating filling to realize sand prevention. The 'two-step method' well completion operation needs two running of the pipe column, the working period is long, the cost is high, and two operations need to be performed for mobilization. Particularly for offshore oil and gas fields, the daily cost of the platform is high, the mobilization operation period is long, and the two-step filling is not applicable.

Therefore, it is an important technical problem to be solved by those skilled in the art to provide a filling tool and a completion string which are convenient to fill.

Disclosure of Invention

The invention aims to provide a filling tool and a well completion string so as to relieve the technical problem of inconvenient filling in the prior art.

In a first aspect, an embodiment of the present invention provides a filling tool, including a central tube, a liquid return tube sleeved outside the central tube, and a double-way tube connected to the central tube;

an annular space is reserved between the liquid return pipe and the central pipe, and a liquid return hole communicated with the annular space is formed in the liquid return pipe;

one end of the liquid return pipe is hermetically connected with one end of the central pipe, the other end of the liquid return pipe is hermetically connected with the outer wall of the double-pass pipe, and the other end of the central pipe is hermetically connected with the inner wall of the double-pass pipe;

a through hole communicated with the central pipe is formed in the double-way pipe, and a liquid return channel communicated with the annular space is formed in the pipe wall of the double-way pipe;

be provided with in the bi-pass pipe and be used for the shutoff the sealing of bi-pass pipe, the through-hole is located the sealing with between the center tube.

With reference to the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the number of the through holes is multiple, a liquid discharge sleeve is sleeved in the double-way pipe, liquid discharge channels with the same number as the through holes are formed in the liquid discharge sleeve, and each liquid discharge channel is communicated with a corresponding through hole.

With reference to the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein each of the liquid drainage channels includes a plurality of liquid drainage holes, the plurality of liquid drainage holes are uniformly distributed along the double pipe axis, and the aperture of each of the liquid drainage holes gradually decreases in a direction away from the double pipe.

With reference to the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein a positioning groove is formed in the liquid discharge sleeve, a positioning element adapted to the positioning groove is installed on the double-way pipe, and the liquid discharge channel can correspond to the through hole by positioning the positioning element and the positioning groove.

With reference to the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein a plurality of through holes are uniformly distributed along a circumferential direction of the double-way pipe.

With reference to the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, where the number of the liquid return channels is multiple, the multiple liquid return channels are uniformly distributed along the circumferential direction of the double-way pipe, and the through holes and the liquid return channels are arranged in a staggered manner.

With reference to the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein the filling tool further includes a connecting pipe for connecting to other working strings, and an end of the double-pipe, which is away from the central pipe, is in sealed connection with the connecting pipe.

With reference to the first aspect, an embodiment of the present invention provides a possible implementation manner of the first aspect, wherein a plurality of sealing elements are fixedly sleeved outside the liquid return pipe and the connecting pipe;

the liquid return pipe and the connecting pipe are in sliding seal with the filling sliding sleeve through a sealing piece.

With reference to the first aspect, embodiments of the present invention provide a possible implementation manner of the first aspect, wherein the sealing portion includes a sealing ball seat and a sealing ball fitted with the ball seat;

the sealing ball seat is connected with the bottom of the double-way pipe in a sealing mode.

In a second aspect, embodiments of the present invention provide a completion string, the packing tool.

Has the advantages that:

the invention provides a filling tool, which comprises a central pipe, a liquid return pipe sleeved outside the central pipe and a two-way pipe connected with the central pipe, wherein the liquid return pipe is connected with the central pipe; an annular space is reserved between the liquid return pipe and the central pipe, and a liquid return hole communicated with the annular space is formed in the liquid return pipe; one end of the liquid return pipe is hermetically connected with one end of the central pipe, the other end of the liquid return pipe is hermetically connected with the outer wall of the double-pass pipe, and the other end of the central pipe is hermetically connected with the inner wall of the double-pass pipe; a through hole communicated with the central pipe is formed in the double-way pipe, and a liquid return channel communicated with the annular space is formed in the pipe wall of the double-way pipe; be provided with the sealing that is used for the shutoff double-pass pipe in the double-pass pipe, the through-hole is located between sealing and the center tube.

When the oil well fracturing filling tool is used, the filling tool is put into an oil well which is provided with a sieve tube and is sealed, then the water return channel is sealed, so that liquid in the oil well cannot return out of the ground, then filling liquid is injected into the center tube and pressurized, the filling liquid can flow into the double-pass tube from the center tube and then flows out of the through hole in the double-pass tube, the filling liquid can flow into an annular space between the sieve tube and the inner wall of the oil well under the action of pressure, the filling liquid between the sieve tube and the inner wall of the oil well can complete the fracturing work on a stratum where the inner wall of the oil well is located along with the pressurization and the injection of the filling liquid by a worker, and meanwhile, filling materials carried by the filling liquid can be filled in a fractured gap to; after fracturing filling is finished, opening the water return channel to enable the water return channel to be smooth, continuing to inject filling liquid into the central pipe, enabling filling materials in the filling liquid to be left between the sieve pipe and the inner wall of the oil well, enabling the liquid in the filling liquid to penetrate through the sieve pipe, then enter the liquid return channel of the double-way pipe, flow into the annular space from the liquid return channel, and finally flow into the water return channel from the liquid return hole, enabling the liquid to flow out of the oil well, enabling the sieve pipe and the inner wall of the oil well to be filled, and achieving circular filling; through the arrangement, the fracturing filling and circulating filling work can be conveniently carried out by workers.

The invention provides a completion string, which comprises a filling tool. The completion string has the advantages described above over the prior art and will not be described in further detail herein.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic diagram of a filling tool according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a filling tool showing a fluid return passage according to an embodiment of the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 1 at A;

FIG. 4 is a cross-sectional view of B-B of FIG. 1;

fig. 5 is a schematic structural view of a double-way pipe in the filling tool according to the embodiment of the present invention;

FIG. 6 is a schematic view of a drain bushing of a filling tool according to an embodiment of the present invention;

FIG. 7 is a schematic illustration of a completion string provided in accordance with an embodiment of the present invention when unfilled;

FIG. 8 is a schematic representation of a completion string provided in accordance with an embodiment of the present invention as it is being packed.

Icon:

100-a central tube; 110-an annular space;

200-a liquid return pipe; 210-a liquid return hole;

300-double-way pipe; 310-a through hole; 320-a liquid return channel; 330-a positioning member; 340-a seal; 350-positioning holes;

400-drainage cannula; 410-drain holes; 420-positioning grooves;

500-connecting tube;

600-a seal;

700-setting tool; 710-a packer; 720-filling the sliding sleeve; 730-a sliding sleeve switch;

800-sieve tube; 810-a positioning tool; 820-locating the collar.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "central," "radial," "circumferential," and the like, as used herein, refer to an orientation or positional relationship based on that shown in the drawings, which is for convenience and simplicity of description, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, is not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be a mechanical connection; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The present invention will be described in further detail below with reference to specific embodiments and with reference to the attached drawings.

Referring to fig. 1, 2, 3 and 4, an embodiment of the present invention provides a filling tool, including a central pipe 100, a liquid returning pipe 200 sleeved outside the central pipe 100, and a two-way pipe 300 connected to the central pipe 100; an annular space 110 is reserved between the liquid return pipe 200 and the central pipe 100, and a liquid return hole 210 communicated with the annular space 110 is formed in the liquid return pipe 200; one end of the liquid return pipe 200 is hermetically connected with one end of the central pipe 100, the other end of the liquid return pipe 200 is hermetically connected with the outer wall of the two-way pipe 300, and the other end of the central pipe 100 is hermetically connected with the inner wall of the two-way pipe 300; a through hole 310 communicated with the central pipe 100 is formed in the double-way pipe 300, and a liquid return channel 320 communicated with the annular space 110 is formed in the pipe wall of the double-way pipe 300; a sealing part 340 for sealing the double pipe 300 is provided in the double pipe 300, and the through hole 310 is located between the sealing part 340 and the central pipe 100.

When the fracturing filling tool is used, a filling tool is put into an oil well which is provided with a sieve tube and is sealed, then a water return channel is sealed, so that liquid in the oil well cannot return out of the ground, then filling liquid is injected into the central tube 100 and pressurized, the filling liquid can flow into the double-pass tube 300 from the central tube 100 and then flows out of the through hole 310 on the double-pass tube 300, the filling liquid can flow into an annular space between the sieve tube and the inner wall of the oil well under the action of pressure, along with pressurization and filling liquid injection of workers, the filling liquid between the sieve tube and the inner wall of the oil well can complete fracturing work on a stratum where the inner wall of the oil well is located, and meanwhile, filling materials carried by the filling liquid can be filled in fractured gaps to complete fracturing filling work; after fracturing filling is finished, opening the water return channel to enable the water return channel to be smooth, continuously injecting filling liquid into the central pipe 100 at the moment, enabling filling materials in the filling liquid to be left between the sieve pipe and the inner wall of the oil well, enabling the liquid in the filling liquid to pass through the sieve pipe, then enter the liquid return channel 320 of the double-way pipe 300, flow into the annular space 110 from the liquid return channel 320, and finally flow into the water return channel from the liquid return hole 210, enabling the liquid to flow out of the oil well, enabling the sieve pipe and the inner wall of the oil well to be filled, and achieving circular filling; through the arrangement, the fracturing filling and circulating filling work can be conveniently carried out by workers.

The "water return passage" refers to an annulus between the service string and the oil well, and during circulation filling, liquid in the filling liquid passes through the liquid return passage 320, the annulus space 110 and the liquid return hole 210 of the two-way pipe 300 in sequence, then flows into the water return passage from the liquid return hole 210, and the water return passage is communicated with the ground, so that the liquid of the filling liquid can be discharged out of the oil well.

Specifically, the main flow channel of the double-pass tube 300 is communicated with the central tube 100, and the main flow channel of the double-pass tube 300 is communicated with the through hole 310, when the sealing part 340 blocks the main flow channel of the double-pass tube 300, the filling liquid in the central tube 100 can be discharged from the through hole 310, thereby implementing the fracturing filling work.

Moreover, when the sealing part 340 seals the main flow passage of the double-pipe 300, the liquid flowing from the sieve tube in the oil well does not flow back into the main flow passage of the double-pipe 300, but flows into the liquid return passage 320, flows into the annular space 110 through the liquid return passage 320, and then flows out from the liquid return hole 210, so that the liquid can flow out of the well, thereby realizing the circulating filling work.

Referring to fig. 1, 4, 5 and 6, in the alternative of this embodiment, the number of the through holes 310 is plural, the two-way pipe 300 is sleeved with the liquid discharge sleeve 400, the liquid discharge sleeve 400 is provided with liquid discharge channels having the same number as the through holes 310, and each liquid discharge channel is communicated with the corresponding through hole 310.

Specifically, the number of the through holes 310 of the double-pass tube 300 is the same as the number of the liquid discharge channels of the liquid discharge sleeve 400, and the filling liquid in the central tube 100 can flow into the liquid discharge sleeve 400, flow into the through holes 310 from the liquid discharge channels of the liquid discharge sleeve 400, and flow out from the through holes 310.

Wherein, through the setting of flowing back sleeve 400, can reduce the wearing and tearing of filling liquid to two pass tube 300, reduce cost of maintenance.

Referring to fig. 6, in an alternative of the present embodiment, each drainage channel includes a plurality of drainage holes 410, the plurality of drainage holes 410 are uniformly distributed along the axis of the double pipe 300, and the diameters of the drainage holes 410 are gradually reduced in a direction away from the center pipe 100.

Specifically, the plurality of drain holes 410 form one drain passage, that is, the plurality of drain holes 410 correspond to one through hole 310.

Moreover, the aperture of the liquid discharge holes 410 is gradually reduced in the direction away from the central tube 100, so that the erosion of the filling liquid to each liquid discharge hole 410 is basically kept consistent, the service life of the liquid discharge sleeve 400 is prolonged, and the situation that a single liquid discharge hole 410 is eroded and damaged and other liquid discharge holes 410 are intact is avoided.

Referring to fig. 3, 5 and 6, in an alternative of this embodiment, a positioning groove 420 is formed on the liquid discharge sleeve 400, a positioning member 330 adapted to the positioning groove 420 is installed on the double-pass tube 300, and the liquid discharge channel can correspond to the through hole 310 by positioning the positioning member 330 and the positioning groove 420.

Specifically, through the cooperation of setting element 330 and constant head tank 420, can simplify staff's assembly work, after setting element 330 is connected with constant head tank 420, the drainage channel of flowing back sleeve pipe 400 can correspond with through-hole 310 on the bi-pass pipe 300, need not the staff and adjust the work again, can not appear rotating at filling in-process drainage sleeve pipe 400 moreover.

Wherein, the double-pass tube 300 is provided with a positioning hole 350 for installing the positioning member 330.

Referring to fig. 4, in an alternative of the present embodiment, a plurality of through-holes 310 are uniformly distributed along the circumference of the double-pass pipe 300.

Specifically, the through holes 310 are uniformly distributed along the circumferential direction of the double-way pipe 300, so that the circumferential water yield of the double-way pipe 300 can be balanced, and the radial runout of the double-way pipe 300 is avoided.

Moreover, the impact of the spraying of the filling liquid from the uniformly distributed through holes 310 on the filling sliding sleeve 720 is reduced, and the local erosion of the filling sliding sleeve 720 by the filling liquid is avoided.

It should be noted that the filling sliding sleeve 720 is located in the oil well, and cooperates with the filling tool to complete the filling operation, and the filling sliding sleeve 720 is prior art and will not be described herein.

Referring to fig. 4, in an alternative of this embodiment, the number of the liquid return channels 320 is multiple, the multiple liquid return channels 320 are uniformly distributed along the circumferential direction of the double-pass pipe 300, and the through holes 310 and the liquid return channels 320 are arranged in a staggered manner.

Specifically, the plurality of liquid return channels 320 and the plurality of through holes 310 are arranged on the double-pass pipe 300 in a staggered manner, so that the through holes 310 are prevented from being communicated with the liquid return channels 320.

Referring to fig. 1 and 2, in an alternative of the present embodiment, the filling tool further includes a connection pipe 500 for connecting other working strings, and one end of the two-way pipe 300, which is away from the center pipe 100, is sealingly connected to the connection pipe 500.

Specifically, the base pipe 100 may be coupled to other work strings via a coupling tube 500.

Referring to fig. 1 and 2, in an alternative of this embodiment, a plurality of sealing members 600 are fixedly sleeved outside both the liquid return pipe 200 and the connecting pipe 500; the liquid return pipe 200 and the connecting pipe 500 are both slidably sealed with the filling sliding sleeve 720 through a sealing member 600.

Specifically, the outer walls of both the return pipe 200 and the connection pipe 500 are provided with the sealing member 600, and the filling liquid discharged from the through hole 310 can be discharged from the liquid discharge port of the filling slide sleeve 720 by the arrangement of the sealing member 600 to perform the filling operation.

Referring to fig. 1 and 2, in an alternative of the present embodiment, the sealing portion 340 includes a sealing ball seat and a sealing ball fitted with the ball seat; the sealing ball seat is sealingly connected to the bottom of the two-way pipe 300.

Wherein, carry out the shutoff to two-way pipe 300 through sealed ball seat and ball sealer, when needs seal work, to throwing into the ball sealer in the center tube 100 and can accomplish seal work.

Wherein, the sealing ball can adopt a steel ball.

Referring to fig. 7 and 8, an embodiment of the present invention provides a completion string including a packing tool. The completion string has the advantages described above over the prior art and will not be described in further detail herein.

When the sealing device is used, the filling tool is sent to a set position in the well, and then a sealing ball is thrown from the well mouth to perform pressing and setting. At this time, the upper and lower ends of the through hole 310 on the setting tool 700 are provided with the sealing element 600, the sealing element 600 is sealed with the filling sliding sleeve 720 on the well-reserved string, and the pressing setting in the oil pipe can be realized to set the packer 710. After setting, the packer 710 is secured to the casing and seals with the casing.

And lifting the service string, lifting the positioning tool 810 above the positioning collar 820, lowering and pressurizing, and positioning the positioning tool 810 on the positioning collar 820. The through hole 310 can correspond to a filling opening of the filling slide sleeve 720, which is a filling operation position. During the filling operation, the sealing element 600 above the through hole 310 moves into the packer 710 to form a seal, and the sealing element 600 below the through hole 310 still seals with the filling shoe 720. After the filling liquid conveyed by the central pipe 100 comes out from the through hole 310, the filling liquid can only enter the filling sliding sleeve 720, and then is discharged from the filling port of the filling sliding sleeve 720 into the annular space between the outside of the screen pipe 800 and the casing pipe, so that the filling operation is completed.

When the service string is lifted, the sliding sleeve switch 730 can open the filling port on the filling sliding sleeve 720, so that the filling liquid can be discharged from the filling port.

In practical application, the fracturing filling is firstly carried out. At this time, the oil sleeve annulus is closed, i.e., the water return channel is closed, so that the filling liquid can only continue to move to the perforation hole after moving out of the filling sliding sleeve 720. At the moment, when the filling discharge capacity and the filling sand ratio reach a certain amount, the gravel can enter the stratum to be filled, the stratum is pressed open to form a crack, and the crack is filled with the filling sand to form an oil extraction channel, so that the aim of modifying the stratum is fulfilled.

After fracturing filling is finished, opening the annular space of the oil sleeve, carrying out small-displacement circulating filling operation at the moment, changing the flow sequence of filling liquid into moving out of the filling sliding sleeve 720, continuously moving downwards to the annular space of the sieve tube 800 and the sleeve, blocking gravel outside the sieve tube 800 by the sieve tube 800, continuously entering liquid return channel 320 of the two-way tube 300 through the sieve tube 800, and further circulating between the oil tube and the sleeve through the annular space 110 and the liquid return hole 210 to return to the ground.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.