Free point fracturing cementing float collar

Abstract

The present application relates to the technical field of downhole tools, and particularly relates to a fracturing and cementing floating collar free from perforation to relieve the problem of low success rate of well completion by conventional fracturing tools. The floating collar has a first state and a second state; in the first state, liquid flows into the first liquid injection channel from the upper part of the body and flows out from the lower part of the body; when switching from the first state to the second state, a rubber plug is put into the body, the rubber plug is clamped with the movable valve core, the flow hole of the rubber plug is docked with the liquid discharge hole, the liquid discharge hole is communicated with the outside to form the second liquid injection channel, and in the second state, liquid flows into the first liquid injection channel and the second liquid injection channel from the upper part of the body. In the fracturing operation process, the displacement fluid replaces the cement layer of the original fracturing operation section, which facilitates the pressure transmission to the formation, can effectively improve the success rate of the fracturing operation, and at the same time, the lower part can effectively reduce the pressure at the wellhead through the multi-channel liquid discharge.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of downhole tools, in particular to a fracturing well cementing float collar without perforation. BACKGROUND

[0002] After well cementing, downhole fracturing is needed, which is to inject high-pressure fluid into the oil and gas reservoir to form a pressure at the well bottom that is enough to exceed the rock fracture pressure, so as to make the reservoir rock produce cracks and provide new flow channels for oil and gas, thereby improving the seepage capacity of oil and gas from the reservoir to the wellbore and achieving the purpose of increasing production.

[0003] Horizontal well fracturing often uses pump bridge plug segmented fracturing technology, and the casing completion horizontal well fracturing process mainly includes: the first section uses coiled tubing transmission perforation and casing fracturing, the remaining sections use cable pumping bridge plug, cluster perforation, and segmented fracturing. After fracturing is completed, the bridge plug is drilled and grinded for production. However, during coiled tubing operation, due to the influence of factors such as complex well trajectory, large deviation angle and dogleg, and "upward" type at the end of the horizontal section, problems such as sticking, self-locking, and dropping are prone to occur. In addition, the coiled tubing is prone to flexural deformation, making the operation more and more difficult; and from the installation of the coiled tubing, the perforating gun is put into the well, to the coiled tubing equipment leaving the site, it takes at least 5-8 days, and if the coiled tubing is self-locked, a large amount of expensive metal drag-reducing agent needs to be injected, which not only greatly increases the cost, but also causes damage to the reservoir.

[0004] Among them, the first section of the well cementing fracturing toe sleeve tool is used as the first stage fracturing sleeve, which is put into the well together with the casing to the predetermined position, and the surrounding needs to be filled with cement to solidify, so that this device is not only expensive, but also has a low success rate in field construction, so a tool is needed to replace the toe sleeve. SUMMARY

[0005] To alleviate the above technical problems, the technical solution provided by the present application is as follows:

[0006] The present application provides a fracturing well cementing float collar without perforation, which includes a first state and a second state.

[0007] In the first state, the liquid flows into the first liquid injection channel from the upper part of the body and flows out from the lower part of the body;

[0008] When switching from the first state to the second state, the rubber plug is put into the body, the rubber plug is clamped with the movable valve core, the first liquid injection channel is closed, the movable valve core is moved downward under pressure, the movable valve core is communicated with the liquid discharge hole of the body, and the movable valve core is continuously moved downward under pressure again, so that the overflow hole of the rubber plug is butted with the liquid discharge hole;

[0009] The liquid discharge hole is communicated with the outside to form a second liquid injection channel;

[0010] In the second state, liquid flows from the upper part of the body and is divided into the first liquid injection channel and the second liquid injection channel.

[0011] Further,

[0012] A valve core sleeve is arranged in the body;

[0013] The movable valve core is threadedly connected with the upper part of the valve core sleeve;

[0014] The valve core sleeve is slidingly connected with the body;

[0015] The valve rod is inserted into the valve core sleeve;

[0016] There is a gap between the movable valve core and the valve rod, and between the valve core sleeve and the valve rod;

[0017] The movable valve core and the valve rod communicate to form the first liquid injection channel.

[0018] Further,

[0019] A spring is arranged between the valve rod and the valve core sleeve.

[0020] Further,

[0021] A fixed valve core is arranged at the upper part of the valve core sleeve;

[0022] The outer wall of the fixed valve core is threadedly connected with the body;

[0023] The movable valve core is inserted into the fixed valve core and is fixedly connected through the first shear pin.

[0024] Further,

[0025] The rubber plug comprises a main body, an inner sleeve and an outer sleeve;

[0026] The inner sleeve is slidingly connected with the main body and is fixedly connected through the second shear pin;

[0027] The outer sleeve is clamped with the outer wall of the main body.

[0028] Further,

[0029] After the rubber plug is put into the body, the lower part of the rubber plug abuts against the movable valve core, and after the first shear pin is broken by the first pressurization, the rubber plug moves downward with the movable valve core;

[0030] After the outer wall of the rubber plug abuts against the fixed valve core, the rubber plug stops moving, so that the circulation hole on the movable valve core communicates with the liquid discharge hole.

[0031] Further,

[0032] After the second pressurization, the second shear pin is broken, the inner sleeve pushes the movable valve core to move downward, so that the overflow hole is opposite to the liquid discharge hole, and the overflow hole communicates with the liquid discharge hole and the circulation hole, respectively.

[0033] Further,

[0034] The overflow hole is an elongated hole and has a size greater than the drainage hole.

[0035] Further,

[0036] The first shear nail is broken after bearing a shear force of 30 MPa.

[0037] Further,

[0038] The second shear nail is broken after bearing a shear force of 35 MPa.

[0039] The beneficial effects of the non-perforation fracturing and cementing floating collar in the present application are analyzed as follows:

[0040] The present application provides a non-perforation fracturing and cementing floating collar, comprising a first state and a second state; in the first state, liquid flows into the first liquid injection channel from the upper part of the body and flows out from the lower part of the body; when switching from the first state to the second state, a rubber plug is put into the body, the rubber plug is clamped with the movable valve core, the first liquid injection channel is closed, the movable valve core is moved downward after being pressurized, the movable valve core is communicated with the drainage hole of the body, and the movable valve core is continuously moved downward again, so that the overflow hole of the rubber plug is butted with the drainage hole; the drainage hole is communicated with the outside to form a second liquid injection channel; in the second state, liquid flows into the first liquid injection channel and the second liquid injection channel from the upper part of the body.

[0041] In the first state, the device has the effect of one-way valve and packer, which can avoid the reverse flow of well bottom liquid, facilitate the completion of cementing work, and after the completion of cementing operation, the device can be used for fracturing operation by putting in the rubber plug, in the fracturing operation process, the cement layer of the original fracturing operation section is replaced by the displacement fluid, which facilitates the pressure transmission to the formation, can effectively improve the success rate of fracturing operation, and the lower part can effectively reduce the pressure of the wellhead through the multi-channel drainage. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the specific embodiments or the related art, the drawings needed to be used in the specific embodiments or the related art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0043] Figure 1 The structure schematic diagram of the non-perforation fracturing and cementing floating collar in the first state is provided for the embodiments of the present application.

[0044] Figure 2 The structure schematic diagram of the rubber plug is provided.

[0045] Figure 3 Structure diagram of the floating collar for the fracturing and cementing without perforation after the rubber plug is put in;

[0046] Figure 4 Structure diagram of the floating collar for the fracturing and cementing without perforation after the first shear pin is broken;

[0047] Figure 5 Structure diagram of the floating collar for the fracturing and cementing without perforation provided by the embodiment of the present application in the second state.

[0048] Icon:

[0049] 100 - body; 110 - drainage hole;

[0050] 200 - rubber plug; 210 - flow hole; 220 - main body; 230 - inner sleeve; 240 - outer sleeve; 250 - second shear pin;

[0051] 300 - movable valve core; 310 - first shear pin; 320 - circulation hole;

[0052] 400 - valve core sleeve;

[0053] 500 - valve rod;

[0054] 600 - spring;

[0055] 700 - fixed valve core. DETAILED DESCRIPTION

[0056] Since the existing toe sliding sleeve tool is used as the first-stage fracturing sliding sleeve, the cost is high and the success rate of construction is low, and it is difficult to meet the conventional requirements.

[0057] Therefore, as shown in the present application, a floating collar for the fracturing and cementing without perforation is provided to alleviate the above problems. Figures 1 to 5

[0058] The device includes a first state and a second state;

[0059] In the first state, the liquid flows into the first liquid injection channel from the upper part of the body 100 and flows out from the lower part of the body 100;

[0060] When switching from the first state to the second state, the rubber plug 200 is put into the body 100, the rubber plug 200 is clamped with the movable valve core 300, the first liquid injection channel is closed, the movable valve core 300 is moved downward under pressure, the movable valve core 300 is communicated with the drainage hole 110 of the body 100, and the movable valve core 300 is continuously moved downward under pressure again, so that the flow hole 210 of the rubber plug 200 is butted with the drainage hole 110;

[0061] ​The drainage hole 110 is in communication with the outside to form a second liquid injection channel;

[0062] In the second state, liquid flows into the upper part of the body 100 and is divided into the first liquid injection channel and the second liquid injection channel.

[0063] Specifically, the device is connected to the lower part of the casing string. During the cementing operation, preflush, cement slurry and displacement drilling fluid are sequentially injected. During this process, liquid flows into the body 100 from the casing string and flows out from the lower part of the body 100 along the first liquid injection channel, so that the cement slurry and the displacement drilling fluid enter the annular space between the casing and the well wall. After confirming that the annular space is filled with cement slurry and displacement drilling fluid, the rubber plug 200 is put into the casing string, and the rubber plug 200 is sent into the body 100 by a pressure less than 25 MPa, so that the rubber plug 200 abuts against the movable valve core 300, and the snap spring at the lower part of the rubber plug 200 is clamped to prevent the rubber plug 200 from returning due to changes in bottom hole pressure. When the cement slurry is solidified after the cementing is completed and the fracturing operation is prepared, the wellhead is gradually pressurized, and finally the movable valve core 300 is lowered to a predetermined position, so that the first liquid injection channel and the second liquid injection channel are respectively in communication with the casing string, so that the liquid in the casing string entering the body 100 flows out along the first liquid injection channel or the second liquid injection channel.

[0064] In the present scheme, the valve core sleeve 400 is arranged in the body 100;

[0065] The movable valve core 300 is threadedly connected to the upper part of the valve core sleeve 400;

[0066] The valve core sleeve 400 is slidably connected to the body 100;

[0067] The valve rod 500 is inserted into the valve core sleeve 400;

[0068] The movable valve core 300 and the valve rod 500, and the valve core sleeve 400 and the valve rod 500 have gaps therebetween;

[0069] The movable valve core 300 and the valve rod 500 form the first liquid injection channel in communication;

[0070] The spring 600 is arranged between the valve rod 500 and the valve core sleeve 400;

[0071] The fixed valve core 700 is arranged at the upper part of the valve core sleeve 400;

[0072] The outer wall of the fixed valve core 700 is threadedly connected to the body 100;

[0073] The movable valve core 300 is inserted into the fixed valve core 700 and is fixedly connected by the first shear pin 310.

[0074] Specifically, the top of the valve stem 500 is in the shape of an umbrella, the lower part of the movable valve core 300 has a slope matched with the umbrella surface of the valve stem 500, and there is always a gap between the umbrella surface and the slope. The lower part of the valve stem 500 is inserted into the valve core sleeve 400, and there is a gap between them for liquid to pass through. The spring 600 is a compression spring that always has the ability to drive the valve stem 500 to move upward. When the amount of liquid entering the movable valve core 300 is large, the spring 600 is compressed and shrinks, so that the gap between the movable valve core 300 and the valve stem 500 increases. When the amount of liquid is small, the spring 600 resets, so that the gap between the movable valve core 300 and the valve stem 500 resets.

[0075] In the present scheme, the rubber plug 200 comprises a main body 220, an inner sleeve 230 and an outer sleeve 240;

[0076] The inner sleeve 230 is in sliding connection with the main body 220 and is fixedly connected through the second shear pin 250;

[0077] The outer sleeve 240 is in clamping connection with the outer wall of the main body 220;

[0078] After the rubber plug 200 is put into the body 100, the lower part of the rubber plug 200 abuts against the movable valve core 300. After the first shear pin 310 is broken by the first pressurization, the rubber plug 200 moves downward with the movable valve core 300;

[0079] After the outer wall of the rubber plug 200 abuts against the fixed valve core 700, the rubber plug 200 stops moving, so that the circulation hole 320 on the movable valve core 300 is in communication with the liquid discharge hole 110;

[0080] After the second pressurization, the second shear pin 250 is broken, the inner sleeve 230 pushes the movable valve core 300 to move downward, so that the overflow hole 210 is directly opposite to the liquid discharge hole 110, and the overflow hole 210 is in communication with the liquid discharge hole 110 and the circulation hole 320 respectively;

[0081] The first shear pin 310 is broken after bearing a shear force of 30 MPa;

[0082] The second shear pin 250 is broken after bearing a shear force of 35 MPa.

[0083] Specifically, the bottom of the inner sleeve 230 is a closed structure. After the first shear pin 310 is broken, the rubber plug 200 and the movable valve core 300 move downward synchronously. When the protrusion of the main body 220 is clamped with the fixed valve core 700, the movement stops, and at this time, the circulation hole 320 is opposite to the drainage hole 110. At the same time, after being pressurized again, the second shear pin 250 is broken, and the inner sleeve 230 and the movable valve core 300 move downward synchronously. After moving to the predetermined position, the overflow hole 210 is opposite to the drainage hole 110. Because the overflow hole 210 is a long hole and its size is larger than that of the drainage hole 110, the injected liquid can fully enter the cavity formed by the body 100, the inner sleeve 230 and the movable valve core 300, thereby causing the liquid to be divided into two parts. One part is discharged to the outside through the drainage hole 110, and the other part flows into the movable valve core 300 through the circulation hole 320, and then flows downward through the gap between the valve rod 500 and the valve core sleeve 400, thereby increasing the liquid flow through the enlarged drainage outlet, and then reducing the wellhead pressure to facilitate subsequent fracturing operation.

[0084] The present scheme has at least the following beneficial effects:

[0085] When the toe sleeve is used conventionally, there is cement filling between the toe sleeve and the formation. During fracturing operation, the cement needs to be expanded and cracked before the formation is fractured, which results in poor pressure efficiency and low success rate. The present scheme provides a floating collar for well cementing and fracturing without perforation, which is used to replace the toe sleeve in fracturing operation. During well cementing operation, liquid flows from top to bottom, and the tool can avoid the reverse flow of liquid at the bottom of the well. During fracturing operation, the bottom cement slurry is lifted by displacing the drilling fluid, so that the well section to be fractured is not disturbed by the solidified cement, and the formation is fractured by the expansion of liquid, which effectively reduces the wellhead pressure and greatly improves the success rate of operation.

[0086] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A floating collar for cementing well without perforation and fracturing, characterized in that: it comprises a first state and a second state; in the first state, liquid flows into a first liquid injection channel from the upper part of the body (100) and flows out from the lower part of the body (100); when switching from the first state to the second state, a rubber plug (200) is put into the body (100), the rubber plug (200) is clamped with a movable valve core (300), the first liquid injection channel is closed, the movable valve core (300) is moved downward under pressure, the movable valve core (300) is communicated with the liquid discharge hole (110) of the body (100), and the movable valve core (300) is continuously moved downward under pressure again, so that the overflow hole (210) of the rubber plug (200) is butt jointed with the liquid discharge hole (110); the liquid discharge hole (110) is communicated with the outside to form a second liquid injection channel; in the second state, the liquid flows into the first liquid injection channel and the second liquid injection channel from the upper part of the body (100); a valve core sleeve (400) is arranged in the body (100); the movable valve core (300) is threadedly connected with the upper part of the valve core sleeve (400); the valve core sleeve (400) is slidingly connected with the body (100); a valve rod (500) is inserted into the valve core sleeve (400); there is a gap between the movable valve core (300) and the valve rod (500), and between the valve core sleeve (400) and the valve rod (500); the movable valve core (300) and the valve rod (500) form a first liquid injection channel in communication; a fixed valve core (700) is arranged at the upper part of the valve core sleeve (400); the outer wall of the fixed valve core (700) is threadedly connected with the body (100); the movable valve core (300) is inserted with the fixed valve core (700) and is fixedly connected through a first shear pin (310).

2. The floating collar for cementing well without perforation and fracturing according to claim 1, characterized in that: a spring (600) is arranged between the valve rod (500) and the valve core sleeve (400).

3. The floating collar for cementing well without perforation and fracturing according to claim 2, characterized in that: the rubber plug (200) comprises a main body (220), an inner sleeve (230) and an outer sleeve (240); the inner sleeve (230) is slidingly connected with the main body (220) and is fixedly connected through a second shear pin (250); and the outer sleeve (240) is clamped with the outer wall of the main body (220).

4. The floating collar for cementing well without perforation and fracturing according to claim 3, characterized in that: after the rubber plug (200) is put into the body (100), the lower part of the rubber plug (200) abuts against the movable valve core (300), the first shear pin (310) is broken after the first pressure, and the rubber plug (200) moves downward with the movable valve core (300). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The outer wall of the rubber plug (200) abuts against the fixed valve core (700), and the rubber plug (200) stops moving, so that the circulation hole (320) on the movable valve core (300) communicates with the drainage hole (110).

5. The floating collar of claim 4, wherein: After the second pressure is applied, the second shear pin (250) breaks, the inner sleeve (230) pushes the movable valve core (300) to move downward, so that the flow passage (210) is opposite to the drainage hole (110), and the flow passage (210) communicates with the drainage hole (110) and the circulation hole (320) respectively.

6. The floating collar of claim 5, wherein: The flow passage (210) is a long hole, and the size is greater than that of the drainage hole (110).

7. The floating collar of claim 6, wherein: The first shear pin (310) breaks after bearing a shear force of 30 MPa.

8. The floating collar of claim 7, wherein: The second shear pin (250) breaks after bearing a shear force of 35 MPa.

Images