Casing running, fracturing, and completion integrated string and method of use

Abstract

The application provides a casing running, fracturing, cementing and well completion integrated pipe column and a use method thereof. The casing running, fracturing, cementing and well completion integrated pipe column comprises a tail pipe string, a casing string and a sealing plug. The tail pipe string comprises a tail pipe hanger, a plurality of full-bore cementing sliding sleeves arranged below the tail pipe hanger and a toe end sliding sleeve arranged above the tail pipe hanger. The casing string is connected to the upper end of the tail pipe string in a plug-in mode, and is separated from the sealing plug by positive rotation of the casing string, so that the casing string is released. The application satisfies cementing construction, fracturing and casing pulling out operation after fracturing, and realizes large-bore production.

Description

Technical Field

[0001] This invention relates to an integrated casing insertion string for fracturing, cementing, and completion, and its application method, belonging to the field of cementing and completion technology for oil and gas wells. Background Technology

[0002] China possesses abundant shale gas resources, with recoverable resources ranging from 11.5 trillion to 36.1 trillion cubic meters. Deep shale gas, buried at depths exceeding 3500 meters, accounts for over 80% of these resources. Increasing exploration and development of deep shale gas is of significant strategic importance for ensuring national energy security. Compared to shallow shale gas, deep shale gas exhibits significant changes in reservoir depth, temperature, pressure, and geostress. To improve reservoir encounter rates, the demand for ultra-long horizontal well sections is constantly increasing, posing a series of technical challenges to cementing engineering.

[0003] After horizontal well completion, if the wellbore conditions do not meet the requirements for open-hole completion string running or construction, full-casing cementing operations suffer from poor wellbore cleanliness, low displacement efficiency, and difficulty in ensuring cementing quality. Furthermore, overlapping casing usage significantly increases development costs. Simultaneously, full-casing cementing teams face significant limitations in subsequent fracturing operations. Secondly, the difficulty in ensuring full-casing cementing quality increases the risk of wellhead pressure during later fracturing operations, threatening safe production. While existing tailpipe cementing followed by fracturing technology can provide a high-pressure, full-bore wellbore for later reservoir stimulation methods such as fracturing, subsequent fracturing operations still require reservoir stimulation processes such as pumping bridge plugs and perforation fracturing. This process is complex, time-consuming, and costly, and issues such as unset bridge plugs can prevent fracturing operations from being completed. Additionally, tailpipe cementing followed by fracturing operations results in complex string structures with numerous and large diameter variations, complex rubber plug systems, and difficulty in guaranteeing isolation and scraping effects, posing a risk of partial formation burial and affecting final production. Furthermore, the fracturing operation following tailpipe cementing requires two sets of tubing strings, resulting in a long construction period and high operating costs. Summary of the Invention

[0004] To address the aforementioned technical problems in the existing technology, this invention proposes an integrated casing insertion string for fracturing, cementing, and completion, and its usage method, which meets the requirements of cementing construction, fracturing, and casing retrieval operations after fracturing, and enables large-diameter production.

[0005] According to one aspect of the present invention, a casing insertion fracturing and cementing completion integrated tubing string is provided, comprising:

[0006] A tailpipe string, comprising a tailpipe hanger, with several full-bore cementing sleeves and a toe sleeve disposed below the tailpipe hanger, and a sealing plug disposed above the tailpipe hanger; and

[0007] A sleeve string is connected to the upper end of the tail tube string. The sleeve string is fixedly connected to the sealing plug by plugging. The sleeve string is separated from the sealing plug by rotating it in the forward direction, so as to release the handle.

[0008] A further improvement of the present invention is that a ball seat is connected below the toe end sleeve, and after the pressure ball is put into the wellhead, the tailpipe string is pressurized so as to sit on the tailpipe hanger.

[0009] A further improvement of the present invention is that different sizes of sliding sleeve keys are provided inside the different full-bore cementing sliding sleeves. After the wellhead transfer device is put in, it is connected to the sliding sleeve key and the full-bore cementing sliding sleeve is opened.

[0010] A further improvement of the present invention is that the sliding key and the layer transfer device are made of soluble materials that dissolve after a period of time in the downhole environment.

[0011] A further improvement of the present invention is that a float band is connected below the ball seat, and a float shoe is connected below the float band.

[0012] A further improvement of the present invention is that the tailpipe hanger hydraulic cylinder adopts a Glyd ring combination sealing form, and the sealing plug adopts a metal skeleton vulcanized rubber sealing form.

[0013] According to another aspect of the present invention, a method for reconnecting a fracturing, cementing, and completion integrated tubing string after cementing using a tailpipe is also provided, comprising:

[0014] Assemble the tailpipe string, lower the lower part of the tailpipe string downhole, and connect the upper part to the casing string;

[0015] The tailpipe string is lowered to the design position using the casing string, the tailpipe hanger is set up, and then cementing operations are carried out.

[0016] To carry out fracturing operations, the toe sleeve and the full-bore cementing sleeve are opened to perform fracturing operations in stages.

[0017] The forward rotation of the bushing string enables both dropping and retrieval.

[0018] A further improvement of the present invention is that the tailpipe hanger setting process includes: placing a setting pressure ball at the wellhead, the pressure ball being engaged with a ball seat to pressurize the tailpipe string, thereby setting the tailpipe hanger under pressure.

[0019] A further improvement of the present invention is that, during cementing operations, a cementing plug is thrown at the wellhead to carry out cementing operations. After the cement slurry returns to the vicinity of the tailpipe hanger, the casing string is rotated clockwise to complete the release operation, and excess cement slurry is circulated out. Then, the casing string is inserted back to its original position.

[0020] A further improvement of the present invention is that, during the fracturing operation, pressure is first applied inside the tubing string, the toe sleeve is opened, and the first stage of fracturing begins.

[0021] Then, different sized transfer devices were deployed from the wellhead to open different full-bore cementing sleeves, completing the fracturing operation of each section.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] This invention discloses an integrated casing-driven fracturing, cementing, and completion string that combines tailpipe suspension cementing, casing cementing, and reservoir stimulation fracturing and completion processes. A single string run can meet the needs of cementing and completion operations. Fracturing is performed by directly pumping the switch key from the wellhead and applying pressure in stages to open the toe sleeve and pre-installed cementing sleeve, eliminating the need for pumping bridge plugs or perforation, thus saving time and costs. After fracturing, the return string can be easily removed by rotating the string forward, allowing for reuse and improving resource utilization, significantly reducing costs and providing excellent economic and social benefits. Simultaneously, production operations can be carried out within the upper casing, completely eliminating the technical challenges of annular pressure in oil and casing production while meeting the large-diameter requirements for subsequent production stimulation.

[0024] All tools in this invention adopt an ultra-high pressure sealing structure design, and the sealing capacity of the integrated cementing and completion tubing string reaches 105MPa, which meets the high pressure requirements of fracturing operations; the casing string has a full bore, which is conducive to cementing plug isolation and scraping, the plug system is simple, and the cementing quality can be guaranteed.

[0025] In this invention, the casing string can be anchored and sealed simply by pressing it down, and the casing string can be released by rotating it forward. This reduces the probability of risk and allows for the recycling and reuse of the tailstock. The tailstock has a pre-installed toe sleeve and cementing sleeve, eliminating the need for bridge plug insertion and perforation operations, effectively reducing construction time and making construction safe and convenient.

[0026] In this invention, the sliding sleeve key switch and other components are made of soluble materials that can dissolve within a certain time, ensuring the full bore of the tailpipe string after fracturing operations, eliminating the need for subsequent squeezing and plugging operations. Attached Figure Description

[0027] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which:

[0028] Figure 1 The diagram shown is a schematic diagram of the casing insertion and fracturing / solidification well completion integrated tubing string according to an embodiment of the present invention.

[0029] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not drawn to scale.

[0030] The meanings of the reference numerals in the attached figures are as follows:

[0031] 1. Tailpipe string, 2. Casing string, 11. Tailpipe hanger, 12. Toe sleeve, 13. Full-bore cementing sleeve, 14. Ball seat, 15. Float collar, 16. Float shoe, 17. Sealing plug. Detailed Implementation

[0032] To make the technical solutions and advantages of the present invention clearer, exemplary embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not an exhaustive list of all embodiments. Furthermore, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0033] Figure 1 The diagram schematically illustrates an integrated casing-feeding fracturing, cementing, and completion string according to the present invention, comprising a tailpipe string 1, a tailpipe hanger 11, a plurality of full-bore cementing sleeves 13 disposed below the tailpipe hanger 11, a toe sleeve 12 disposed below the plurality of full-bore cementing sleeves 13, and a sealing plug 17 disposed above the tailpipe hanger 11. A casing string 2 is disposed at the upper end of the tailpipe string 1, the casing string 2 being fixedly connected to the sealing plug 17 by a plug-in connection, and being released by rotating the casing string 2 forward to separate it from the sealing plug 17.

[0034] In the integrated fracturing, cementing, and completion string described in this embodiment, a single run of the string consisting of the tailpipe string 1 and the casing string 2 can meet the cementing and completion operations, effectively reducing tripping time and significantly lowering construction costs.

[0035] Preferably, the casing string 2 and the sealing plug 17 are connected by a toothed threaded hole and a screw or threaded plate with a certain elasticity. During insertion, the screw or threaded plate undergoes elastic deformation under pressure, thereby locking into the threaded hole. Due to the toothed thread, it cannot slip out. This satisfies the function of running the casing string and overcoming the upward push of the casing string during fracturing. When separation is required, rotating the casing string 2 in the forward direction allows it to separate along the thread, achieving a release. After fracturing, rotating the casing string in the forward direction allows for the recycling and reuse of the casing string, reducing well construction costs.

[0036] In one embodiment, a ball seat 14 is connected below the toe sleeve 12. When the tailpipe string 1 is sent to the predetermined position downhole, a pressure ball is put into the wellhead. The pressure ball moves to the position of the ball seat 14 and is locked on the ball seat 14, so that the tailpipe string 1 above the ball seat 14 is pressured and thus the tailpipe hanger 11 is seated.

[0037] In one embodiment, different sizes of sliding sleeve keys are provided inside different full-bore cementing sliding sleeves 13. After the wellhead transfer device is inserted, it is connected to the sliding sleeve key and the full-bore cementing sliding sleeve 13 is opened.

[0038] According to this embodiment, the casing is sent into the integrated fracturing, cementing, and completion string. The sliding key is inside the outer shell of the full-bore cementing sliding sleeve 13. In the initial state, it blocks the fracturing hole of the outer shell of the full-bore cementing sliding sleeve 13. When the layer transfer device is put in, the layer transfer device is connected to the sliding key, and the sliding key slides under the pushing action of pressure. At this time, the fracturing hole is exposed, so that fracturing operations can be carried out.

[0039] The sliding key sizes of the full-bore cementing sliding sleeve 13 are different for different sections. Preferably, the sliding key size of the upper full-bore cementing sliding sleeve 13 is larger, and the sliding key size of the lower full-bore cementing sliding sleeve 13 is smaller. When the layer changer is inserted, the layer changer will pass smoothly above the matching sliding key and finally snap into the matching sliding key, thereby opening the full-bore cementing sliding sleeve 13.

[0040] In one embodiment, the sliding sleeve key and the transfer device are made of soluble materials that dissolve after a period of time in the downhole environment. Preferably, the ball seat 14 and the pressure ball are also made of soluble materials. After a period of time following the completion of the fracturing operation, the sliding sleeve key and the transfer device melt, ensuring the full bore of the tailpipe string 1, after which the production tubing is lowered in to begin production operations, eliminating the need for subsequent plugging operations.

[0041] In one embodiment, the lower end of the ball seat 14 is connected to a float hoop 15 via a sleeve, and the lower end of the float hoop 15 is connected to a float shoe 16 via a sleeve.

[0042] In one embodiment, the tailpipe hanger 11 uses a Glyd ring combination seal at the hydraulic cylinder, and the sealing plug 17 uses a metal-reinforced vulcanized rubber seal. The overall tubing string sealing capacity reaches 105 MPa, meeting the requirements of high-pressure fracturing.

[0043] According to another aspect of the present invention, a method for reconnecting a fracturing, cementing, and completion integrated tubing string after cementing using the tailpipe described in the above embodiments is also proposed, the method comprising:

[0044] Assemble tailpipe string 1, lower the tailpipe string 1 downhole, and connect the upper part to casing string 2;

[0045] The tailpipe string 1 is lowered to the design position through the casing string 2, the tailpipe hanger 11 is set up, and then cementing operation is carried out.

[0046] To carry out fracturing operations, the toe sleeve 12 and the full-bore cementing sleeve 13 are opened to carry out segmented fracturing operations.

[0047] The forward-rotating bushing string 2 enables the release and retrieval of the sleeve.

[0048] In a preferred embodiment, the process of setting up the tailpipe hanger 11 includes: placing a pressure-retaining ball at the wellhead, the pressure-retaining ball being engaged with the ball seat 14 to pressurize the tailpipe string 1, thereby setting up the tailpipe hanger 11 under pressure.

[0049] In a preferred embodiment, during cementing operations, a cementing plug is dropped at the wellhead (since the casing string 2 is used for installation, all tools have the same diameter, so a uniform cementing plug can be used, eliminating the need for other plug combinations, which can effectively improve the scraping and isolation effect), and cementing operations are carried out. After the cement slurry returns to the vicinity of the tailpipe hanger 11, the casing string 2 is rotated clockwise to complete the release operation, and excess cement slurry is circulated out. Then, the casing string 2 is inserted back to its original position.

[0050] In a preferred embodiment, during fracturing operations, pressure is first applied inside the tubing string, the toe sleeve 12 is opened, and the first stage of fracturing begins.

[0051] Then, different sizes of transfer devices were deployed from the wellhead, and different full-bore cementing sleeves 13 were opened to complete the fracturing construction of each section.

[0052] In this invention, the upper part is the direction closer to the wellhead, and the lower part is the direction farther away from the wellhead.

[0053] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and / or modifications falling within the scope of the invention, and all changes and / or modifications made according to embodiments of the invention should be covered within the protection scope of the invention.

Claims

1. A casing insertion, fracturing, cementing, and completion integrated tubing string, characterized in that, include: A tailpipe string (1) includes a tailpipe hanger (11), below which are several full-bore cementing sleeves (13) and a toe sleeve (12); above the tailpipe hanger (11) is a sealing plug (17); below the toe sleeve (12) is a ball seat (14); after a pressure-absorbing ball is inserted into the wellhead, the tailpipe string (1) is pressurized, thereby suspending the tailpipe hanger (11); and The casing string (2) is connected to the upper end of the tail pipe string (1). The casing string (2) is fixedly connected to the sealing plug (17) by plugging. The casing string (2) is separated from the sealing plug (17) by rotating it forward to release the casing. After cementing, the casing string is rotated forward to complete the release operation, and excess cement slurry is circulated out. Then the casing string is inserted back to its original position. After the fracturing operation is completed, the return pipe string is released by rotating it forward and the return pipe string is taken out. Different sizes of sliding sleeve keys are provided in the different full-bore cementing sliding sleeves (13); during fracturing operations, pressure is first applied in the tubing string, the toe sliding sleeve (12) is opened, the first stage of fracturing begins, and then the wellhead is put into the layer transfer device and connected to the sliding sleeve key to open the full-bore cementing sliding sleeve (13). The sliding key and the layer transfer device are made of soluble materials that dissolve after a period of time in the downhole environment.

2. The integrated casing insertion, fracturing, cementing, and completion string according to claim 1, characterized in that, A float band (15) is connected below the ball seat (14), and a float shoe (16) is connected below the float band (15).

3. The casing insertion fracturing and cementing completion integrated tubing string according to claim 1 or 2, characterized in that, The tailpipe hanger (11) uses a Glyd ring combination sealing method at the hydraulic cylinder, and the sealing plug (17) uses a metal skeleton vulcanized rubber sealing method.

4. A method for using a casing insertion and fracturing / soldering completion integrated tubing string according to any one of claims 1 to 3, characterized in that, include: Assemble the tailpipe string (1), put the lower part of the tailpipe string (1) down into the well, and connect the upper part to the casing string (2). The tailpipe string (1) is lowered to the design position through the casing string (2), the tailpipe hanger (11) is set up, and then cementing operation is carried out. To carry out fracturing operations, open the toe sleeve (12) and the full-bore cementing sleeve (13) to carry out segmented fracturing operations; The forward-rotating bushing string (2) enables the release and recycling of the sleeve.

5. The method of use according to claim 4, characterized in that, The process of setting up the tailpipe hanger (11) includes: placing a pressure-absorbing ball at the wellhead, and attaching the pressure-absorbing ball to the ball seat (14) to pressurize the tailpipe string (1) so that the tailpipe hanger (11) is set up under pressure.

6. The method of use according to claim 4, characterized in that, During cementing operations, cementing plugs are dropped at the wellhead to carry out cementing operations. After the cement slurry returns to the vicinity of the tailpipe hanger (11), the casing string (2) is rotated forward to complete the release operation. Excess cement slurry is circulated out, and then the casing string (2) is inserted back to its original position.

7. The method of use according to claim 4, characterized in that, During fracturing operations, pressure is first applied inside the tubing string, and the toe sleeve (12) is opened to begin the first stage of fracturing. Then, different sizes of transfer devices were deployed from the wellhead, and different full-bore cementing sleeves (13) were opened to complete the fracturing construction of each section.

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