Horizontal well early sand prevention and completion construction method

Abstract

The present disclosure provides a horizontal well early sand prevention and permanent completion construction method, comprising: S1, preparing a wellbore; S2, running a permanent completion pipe string into the wellbore; S3, pressurizing the permanent completion pipe string to expand and seal a middle packer; continuing to pressurize to open a stepped collar, injecting mud into the permanent completion pipe string, and making the mud solidify in the annulus between the casing string and the wellbore; S4, drilling through the stepped collar and the first blind plate, and running an expansion pipe string into the permanent completion pipe string; S5, pressurizing the expansion pipe string, so that the second packer expands and seals in the permanent completion pipe string, and further makes the first packer expand and seal in the wellbore to seal the annulus between the sand prevention casing and the mudstone section. Through the above technical solution, the cementing quality can be improved through cementing operation, and the blocking tool is run into the high-quality reservoir with a mudstone section to block the mudstone section, prevent sand production, and improve oil and gas production rate.

Description

Technical Field

[0001] This disclosure relates to the field of oil and gas cementing and completion technology, and in particular to a method for early sand control and cementing completion of horizontal wells. Background Technology

[0002] Loose sandstone and mudstone reservoirs are prone to sand production, and the amount of sand is large, which affects the later oil production. In addition, the wellbore enlargement rate is large, and conventional packers are difficult to effectively seal the sand. It is also difficult to run the tubing string in horizontal wells. High-quality reservoirs in horizontal sections are mixed with mudstone, which is prone to sand production in the later stages. Therefore, it is necessary to carry out sand control in advance during cementing completion of horizontal wells and optimize the completion method to improve the safety of tubing string running. Summary of the Invention

[0003] One of the technical problems this disclosure aims to solve is that the large amount of sand produced by mudstone near the reservoir affects the production of oil and gas.

[0004] To address the aforementioned technical problems, this disclosure provides a method for pre-sand control and well completion construction of horizontal wells, comprising:

[0005] S1. Prepare the wellbore, which is a horizontal well, and the wellbore includes a vertical section, a build-up section and a horizontal section, and the horizontal section includes a reservoir section and a mudstone section;

[0006] S2. A solidified well completion string is installed into the wellbore. The solidified well completion string includes an upper structure, a middle packer, and a lower structure connected in sequence. The upper structure includes a casing string and a staged collar directly connected to the middle packer. The lower structure includes a first blind plate connected to the middle packer, a screen pipe corresponding to the reservoir section, a sand control casing corresponding to the mudstone section, and a first packer group. The first packer group includes two first packers corresponding to the two ends of the mudstone section.

[0007] S3. Pressurize the solidified well casing string to expand and seal the central packer; continue pressurizing to open the stage collar and inject mud into the solidified well casing string, so that the mud solidifies in the annulus between the casing string and the wellbore;

[0008] S4. Drill through the graded collar and the first blind plate, and run an expansion sealing string into the solidified well string. The expansion sealing string includes tubing and a second packer group corresponding to the first packer group. The second packer group includes two second packers.

[0009] S5. Pressurize the expansion sealing tubing string to cause the second packer to expand and seal in the solidified well tubing string, thereby sealing the annulus between the expansion sealing tubing string and the first packer assembly, and further cause the first packer to expand and seal in the wellbore, thereby sealing the annulus between the sand control casing and the mudstone section.

[0010] In some embodiments, the casing string is provided with a second blind plate located in the build-up section, and there is an air section between the second blind plate and the first blind plate. The area above the second blind plate is filled with mud. In S3, mud is injected into the cemented well completion string to expel the air between the second blind plate and the first blind plate, so that the mud circulates and flows to adjust its performance.

[0011] In some implementations, in S3, after the stage clamp is closed by pressure, the mud in the annulus of the casing string and the wellbore is allowed to solidify.

[0012] In some embodiments, the length of the sand-proof sleeve is greater than the length of the mudstone section.

[0013] In some embodiments, the sieve tube and the first packer are connected by a sleeve.

[0014] In some embodiments, the lower structure is provided with a first guide shoe at its end.

[0015] In some embodiments, the distance between the second packer group is greater than the distance between the first packer group, and the two first packers are disposed between the two second packers.

[0016] In some embodiments, a throttling valve is provided between the two second packers.

[0017] In some embodiments, a second guide shoe is provided at the end of the expansion-sealed tube string.

[0018] In some embodiments, it also includes: S6, depressurizing to cause the second packer to contract and release the expansion seal string.

[0019] In some embodiments, the second packer is a reversible packer, and the first packer and the middle packer are irreversible packers.

[0020] In some embodiments, the cemented well string is equipped with a well-washing valve. In S4, before the expansion sealing string is run in, the well-washing string is run in and the well-washing operation is performed.

[0021] The above technical solutions can improve cementing quality through cementing operations. At the same time, in high-quality reservoirs with mudstone sections, plugging tools can be inserted to seal the mudstone sections, prevent sand production, and increase oil and gas production. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of the cemented well casing string in the wellbore disclosed in this embodiment;

[0024] Figure 2 This is a schematic diagram of the structure of the cemented well string in the wellbore disclosed in this embodiment, wherein the cementing operation has been completed;

[0025] Figure 3 This is a schematic diagram of the structure of the cemented well completion string and the expansion seal string in the wellbore disclosed in this embodiment.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1-Surface casing, 2-Wellbore, 3-Casing string, 4-Second blind flange, 5-Stage clamp, 6-Center packer, 7-First blind flange, 8-Screen pipe, 9-First packer, 10-Wash valve, 11-Second packer, 12-First guide shoe, 13-Tubing, 14-Sand control casing, 15-Choosen valve, 16-Second guide shoe. Detailed Implementation

[0028] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0029] These embodiments are provided to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0030] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] Furthermore, the terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.

[0032] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.

[0033] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0034] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0035] Example 1

[0036] refer to Figures 1-3 As shown, this scheme provides a method for early sand control and cementation completion construction of horizontal wells, which includes:

[0037] S1. Prepare wellbore 2, which is a horizontal well. Wellbore 2 includes a vertical section, a build-up section and a horizontal section. The horizontal section includes a reservoir section and a mudstone section.

[0038] S2. A solidified well completion string is run into the wellbore 2. The solidified well completion string includes an upper structure, a middle packer 6, and a lower structure connected in sequence. The upper structure includes a casing string 3 and a stage collar 5 directly connected to the middle packer 6. The lower structure includes a first blind plate 7 connected to the middle packer 6, a screen pipe 8 corresponding to the reservoir section, a sand control casing 14 corresponding to the mudstone section, and a first packer group. The first packer group includes two first packers 9 corresponding to the two ends of the mudstone section.

[0039] S3. Pressurize the solidified well casing string to expand and seal the middle packer 6; continue pressurizing to open the stage collar 5 and inject mud into the solidified well casing string so that the mud solidifies in the annulus between the casing string 3 and the wellbore 2;

[0040] S4. Drill through the stage clamp 5 and the first blind plate 7, and insert an expansion sealing string into the solidified well string. The expansion sealing string includes tubing 13 and a second packer group corresponding to the first packer group. The second packer group includes two second packers 11.

[0041] S5. Pressurize the expansion sealing tubing string to cause the second packer 11 to expand and seal in the solidified well tubing string, thereby sealing the annulus between the expansion sealing tubing string and the first packer group, and further cause the first packer 9 to expand and seal in the wellbore 2, thereby sealing the annulus between the sand-proof casing 14 and the mudstone section.

[0042] refer to Figure 1 As shown, the wellbore structure can be two-section but is not limited to a two-section structure. Taking a two-section wellbore as an example, the wellbore structure mainly includes the surface casing 1 and the two-section wellbore 2.

[0043] Wellbore 2 includes a vertical section, a build-up section, and a horizontal section. The horizontal section includes a high-quality reservoir section and a mudstone section with a large amount of mud and sand.

[0044] This plan aims to cement the vertical section and part of the directional drilling section, and to seal the mudstone section.

[0045] The cemented well casing string includes a central packer 6 and an upper structure located above it and a lower structure located below it. The upper structure includes a casing string 3 and a stage collar 5. The lower structure includes a screen pipe 8 installed in the reservoir section and a sand-proof casing 14 installed in the mudstone section and a first packer assembly.

[0046] After the cemented casing string is run in, pressure is applied to make the stage collar 5 connected to the annulus. Then, mud is injected from the wellhead into the casing string 3. The mud enters the annulus through the stage collar 5. After the mud solidifies, cementing can be achieved.

[0047] The stage clamp 5 and the first blind plate 7 are opened to ensure that the diameter is not less than 118mm. Then, the expansion sealing string is lowered. The expansion sealing string includes the oil pipe 13 and the second packer group corresponding to the first packer group. Pressurizing the expansion sealing string can cause the second packer 11 to expand and seal in the cemented well completion string to seal the annulus between the expansion sealing string and the first packer group. The first packer 9 continues to expand and seal, thereby blocking the corresponding mudstone section by the first packer 9.

[0048] refer to Figure 3 As shown, two first packer groups are provided, with two first packers 9 in each group sealing the annulus between the sand-proof casing 14 and the mudstone section. The two first packers 9 in each group can be placed in the reservoir section adjacent to the corresponding mudstone section to prevent mud and sand in the mudstone section from flowing into the reservoir section.

[0049] In this scheme, cementing operations can improve cementing quality, while plugging tools are inserted into high-quality reservoirs containing mudstone sections to seal the mudstone sections, prevent sand production, and increase oil and gas production.

[0050] In some embodiments, the casing string 3 is provided with a second blind plate 4 located in the build-up section. An air section exists between the second blind plate 4 and the first blind plate 7. The area above the second blind plate 4 is filled with drilling mud. In step S3, drilling mud is injected into the cemented casing string to expel the air between the second blind plate 4 and the first blind plate 7, allowing the drilling mud to circulate and adjust its properties. The second blind plate 4 can rupture under certain pressure, and its inner diameter after rupture is consistent with the casing diameter; for example, it can be a glass blind plate. The first blind plate 7 can be a conventional aluminum alloy blind plate, used for pressure-sealing the packer 6, pressure-starting stage clamp 5, and isolating the casing string 3 from the screen pipe 8. The area between the first blind plate 7 and the second blind plate 4 can be filled with air, reducing the overall mass and enabling the floating casing string function. The area above the second blind plate 4 is filled with drilling mud; after the second blind plate 4 is broken by pressure, the air in the air section can be expelled, completing the replacement of drilling mud with air.

[0051] In some embodiments, in S3, after the stage collar 5 is closed by pressure, the mud in the annulus between the casing string 3 and the wellbore 2 is allowed to solidify. Closing the stage collar 5 disconnects the casing string 3 from its external annulus, facilitating the solidification of the mud therein and completing the cementing process.

[0052] In S3, after the second blind flange 4 is broken by pressure, the system is statically vented to allow the mud to replace the air. Then, grouting is performed, and the air between the two blind flanges is completely discharged from the wellhead by grouting while venting, and the wellhead is filled with mud. The packer 6 in the middle is expanded by pressure, and the stage collar 5 is opened by pressure to establish a cementing circulation channel. The mud is circulated and its properties are adjusted. The mud flows from the wellhead through the casing string 3 to the stage collar 5, and then returns from the stage collar 5 to the wellhead. The annulus from the stage collar 5 to the wellhead is completely filled with mud. The stage collar 5 is closed by pressure and allowed to solidify. The cementing quality is then tested.

[0053] In some embodiments, the length of the sand-control casing 14 is greater than the length of the mudstone section. The main part of the sand-control casing 14 is disposed in the mudstone section, and its two ends can extend into adjacent reservoir sections, so that the corresponding two first packers 9 are located in the reservoir sections. The spacing between the two first packers 9 can be 15 meters longer than the length of the corresponding mudstone section, and two sets of first packers 9 can be correspondingly set according to the number of mudstone sections in the formation.

[0054] In some embodiments, the screen tube 8 and the first packer 9 are connected by a sleeve. The sleeve, sand-proof sleeve 14, and sleeve string 3 can be made of the same material.

[0055] Additionally, in some embodiments, a first guide shoe 12 is provided at the end of the lower structure. The first guide shoe 12 seals the end of the lower structure, facilitating pressure testing to inflate and seal the first packer 9 therein, and the first guide shoe 12 can guide the tubing string into the wellbore 2.

[0056] In some embodiments, the distance between the second packer groups is greater than the distance between the first packer groups, and the two first packers 9 are disposed between the two second packers 11. (See reference) Figure 3 As shown, along the length of the tubing string, two first packers 9 are located between two second packers 11. After the two second packers 11 expand and seal, they can seal the annulus (the part between the two second packers 11) between the expanded tubing string and the cemented tubing string. They can also pressurize this part of the annulus, increasing the pressure in the annulus, thereby causing the two first packers 9 to expand and seal in the wellbore 2.

[0057] In some embodiments, a throttle valve 15 is provided between the two second packers 11. The throttle valve 15 connects the inside and outside of the tubing 13 to pressurize the annulus between the expansion-sealing tubing string and the cemented completion tubing string, causing the first packer 9 to expand and seal. Furthermore, the throttling effect of the throttle valve 15 also allows for a faster and easier increase in pressure within the tubing 13, facilitating the expansion and sealing of the second packer 11.

[0058] In addition, in some embodiments, a second guide shoe 16 is provided at the end of the expansion sealing tubing string. The second guide shoe 16 can guide the expansion sealing tubing string into the cemented well completion tubing string, and can also seal the lower end of the expansion sealing tubing string to facilitate pressurization into the tubing string and realize the expansion sealing of the second packer 11.

[0059] In some embodiments, the pre-sand control and cementing completion method for horizontal wells also includes: S6, depressurization, so that the second packer 11 contracts and the expansion seal string is removed. After depressurization, the second packer 11 contracts, releasing the setting of the expansion seal string in the cemented completion string, and then the expansion seal string can be removed, the wellhead equipment installed, and the data acquisition operation can begin.

[0060] In some embodiments, the second packer 11 is a reversible packer, while the first packer 9 and the middle packer 6 are irreversible packers. The second packer 11 can be a K344 packer, the first packer 9 is a compression-type, self-expanding packer, and the middle packer 6 is a hydraulically expanding packer, specifically a packer with a large expansion ratio greater than 20%.

[0061] In some embodiments, the cemented well string is equipped with a well-washing valve 10. In S4, before the expansion sealing string is run in, the well-washing string is run in and a well-washing operation is performed. The well-washing valve 10 is located on the upper side of the first guide shoe 12. Well-washing fluid can be introduced into the wellbore through the well-washing valve 10 to perform the well-washing operation.

[0062] Example 1

[0063] refer to Figures 1-3 As shown, this scheme provides a method for early sand control and cementation completion construction of horizontal wells, which includes:

[0064] S1. Prepare wellbore 2, which is a horizontal well. Wellbore 2 includes a vertical section, a build-up section and a horizontal section. The horizontal section includes a reservoir section and a mudstone section.

[0065] S2. A solidified well completion string is run into the wellbore 2. The solidified well completion string includes an upper structure, a middle packer 6, and a lower structure connected in sequence. The upper structure includes a casing string 3 and a stage collar 5 directly connected to the middle packer 6. The lower structure includes a first blind plate 7 connected to the middle packer 6, a screen pipe 8 corresponding to the reservoir section, a sand control casing 14 corresponding to the mudstone section, and a first packer group. The first packer group includes two first packers 9 corresponding to the two ends of the mudstone section.

[0066] S3. Pressurize the solidified well casing string to expand and seal the middle packer 6; continue pressurizing to open the stage collar 5 and inject mud into the solidified well casing string so that the mud solidifies in the annulus between the casing string 3 and the wellbore 2;

[0067] S4. Drill through the stage clamp 5 and the first blind plate 7, and insert an expansion sealing string into the solidified well string. The expansion sealing string includes tubing 13 and a second packer group corresponding to the first packer group. The second packer group includes two second packers 11.

[0068] S5. Pressurize the expansion sealing tubing string to cause the second packer 11 to expand and seal in the solidified well tubing string, thereby sealing the annulus between the expansion sealing tubing string and the first packer group, and further cause the first packer 9 to expand and seal in the wellbore 2, thereby sealing the annulus between the sand-proof casing 14 and the mudstone section.

[0069] refer to Figure 1 As shown, the wellbore structure can be two-section but is not limited to a two-section structure. Taking a two-section wellbore as an example, the wellbore structure mainly includes the surface casing 1 and the two-section wellbore 2.

[0070] Wellbore 2 includes a vertical section, a build-up section, and a horizontal section. The horizontal section includes a high-quality reservoir section and a mudstone section with a large amount of mud and sand.

[0071] This plan aims to cement the vertical section and part of the directional drilling section, and to seal the mudstone section.

[0072] The cemented well casing string includes a central packer 6 and an upper structure located above it and a lower structure located below it. The upper structure includes a casing string 3 and a stage collar 5. The lower structure includes a screen pipe 8 installed in the reservoir section and a sand-proof casing 14 installed in the mudstone section and a first packer assembly.

[0073] After the cemented casing string is run in, pressure is applied to make the stage collar 5 connected to the annulus. Then, mud is injected from the wellhead into the casing string 3. The mud enters the annulus through the stage collar 5. After the mud solidifies, cementing can be achieved.

[0074] The stage clamp 5 and the first blind plate 7 are opened to ensure that the diameter is not less than 118mm. Then, the expansion sealing string is lowered. The expansion sealing string includes the oil pipe 13 and the second packer group corresponding to the first packer group. Pressurizing the expansion sealing string can cause the second packer 11 to expand and seal in the cemented well completion string to seal the annulus between the expansion sealing string and the first packer group. The first packer 9 continues to expand and seal, thereby blocking the corresponding mudstone section by the first packer 9.

[0075] refer to Figure 3 As shown, two first packer groups are provided, with two first packers 9 in each group sealing the annulus between the sand-proof casing 14 and the mudstone section. The two first packers 9 in each group can be placed in the reservoir section adjacent to the corresponding mudstone section to prevent mud and sand in the mudstone section from flowing into the reservoir section.

[0076] In this scheme, cementing operations can improve cementing quality, while plugging tools are inserted into high-quality reservoirs containing mudstone sections to seal the mudstone sections, prevent sand production, and increase oil and gas production.

[0077] In some embodiments, the casing string 3 is provided with a second blind plate 4 located in the build-up section. An air section exists between the second blind plate 4 and the first blind plate 7. The area above the second blind plate 4 is filled with drilling mud. In step S3, drilling mud is injected into the cemented casing string to expel the air between the second blind plate 4 and the first blind plate 7, allowing the drilling mud to circulate and adjust its properties. The second blind plate 4 can rupture under certain pressure, and its inner diameter after rupture is consistent with the casing diameter; for example, it can be a glass blind plate. The first blind plate 7 can be a conventional aluminum alloy blind plate, used for pressure-sealing the packer 6, pressure-starting stage clamp 5, and isolating the casing string 3 from the screen pipe 8. The area between the first blind plate 7 and the second blind plate 4 can be filled with air, reducing the overall mass and enabling the floating casing string function. The area above the second blind plate 4 is filled with drilling mud; after the second blind plate 4 is broken by pressure, the air in the air section can be expelled, completing the replacement of drilling mud with air.

[0078] In some embodiments, in S3, after the stage collar 5 is closed by pressure, the mud in the annulus between the casing string 3 and the wellbore 2 is allowed to solidify. Closing the stage collar 5 disconnects the casing string 3 from its external annulus, facilitating the solidification of the mud therein and completing the cementing process.

[0079] In S3, after the second blind flange 4 is broken by pressure, the system is statically vented to allow the mud to replace the air. Then, grouting is performed, and the air between the two blind flanges is completely discharged from the wellhead by grouting while venting, and the wellhead is filled with mud. The packer 6 in the middle is expanded by pressure, and the stage collar 5 is opened by pressure to establish a cementing circulation channel. The mud is circulated and its properties are adjusted. The mud flows from the wellhead through the casing string 3 to the stage collar 5, and then returns from the stage collar 5 to the wellhead. The annulus from the stage collar 5 to the wellhead is completely filled with mud. The stage collar 5 is closed by pressure and allowed to solidify. The cementing quality is then tested.

[0080] In some embodiments, the length of the sand-control casing 14 is greater than the length of the mudstone section. The main part of the sand-control casing 14 is disposed in the mudstone section, and its two ends can extend into adjacent reservoir sections, so that the corresponding two first packers 9 are located in the reservoir sections. The spacing between the two first packers 9 can be 20 meters longer than the length of the corresponding mudstone section, and three sets of first packers 9 can be correspondingly set according to the number of mudstone sections in the formation.

[0081] In some embodiments, the screen tube 8 and the first packer 9 are connected by a sleeve. The sleeve, sand-proof sleeve 14, and sleeve string 3 can be made of the same material.

[0082] Additionally, in some embodiments, a first guide shoe 12 is provided at the end of the lower structure. The first guide shoe 12 seals the end of the lower structure, facilitating pressure testing to inflate and seal the first packer 9 therein, and the first guide shoe 12 can guide the tubing string into the wellbore 2.

[0083] In some embodiments, the distance between the second packer groups is greater than the distance between the first packer groups, and the two first packers 9 are disposed between the two second packers 11. (See reference) Figure 3 As shown, along the length of the tubing string, two first packers 9 are located between two second packers 11. After the two second packers 11 expand and seal, they can seal the annulus (the part between the two second packers 11) between the expanded tubing string and the cemented tubing string. They can also pressurize this part of the annulus, increasing the pressure in the annulus, thereby causing the two first packers 9 to expand and seal in the wellbore 2.

[0084] In some embodiments, a throttle valve 15 is provided between the two second packers 11. The throttle valve 15 connects the inside and outside of the tubing 13 to pressurize the annulus between the expansion-sealing tubing string and the cemented completion tubing string, causing the first packer 9 to expand and seal. Furthermore, the throttling effect of the throttle valve 15 also allows for a faster and easier increase in pressure within the tubing 13, facilitating the expansion and sealing of the second packer 11.

[0085] In addition, in some embodiments, a second guide shoe 16 is provided at the end of the expansion sealing tubing string. The second guide shoe 16 can guide the expansion sealing tubing string into the cemented well completion tubing string, and can also seal the lower end of the expansion sealing tubing string to facilitate pressurization into the tubing string and realize the expansion sealing of the second packer 11.

[0086] In some embodiments, the pre-sand control and cementing completion method for horizontal wells also includes: S6, depressurization, so that the second packer 11 contracts and the expansion seal string is removed. After depressurization, the second packer 11 contracts, releasing the setting of the expansion seal string in the cemented completion string, and then the expansion seal string can be removed, the wellhead equipment installed, and the data acquisition operation can begin.

[0087] In some embodiments, the second packer 11 is a reversible packer, while the first packer 9 and the middle packer 6 are irreversible packers. The second packer 11 can be a K344 packer, the first packer 9 is a compression-type, self-expanding packer, and the middle packer 6 is a hydraulically expanding packer, specifically a packer with a large expansion ratio greater than 20%.

[0088] In some embodiments, the cemented well string is equipped with a well-washing valve 10. In S4, before the expansion sealing string is run in, the well-washing string is run in and a well-washing operation is performed. The well-washing valve 10 is located on the upper side of the first guide shoe 12. Well-washing fluid can be introduced into the wellbore through the well-washing valve 10 to perform the well-washing operation.

[0089] The following describes the construction method of the preferred implementation method of this scheme:

[0090] 1. Wellbore preparation: Based on the requirements of the tubing string, perform well cleaning, electrical logging, and well circulation flushing to ensure unobstructed wellbore flow;

[0091] 2. Prepare tools and tubing based on electrical testing results. For high-quality reservoirs, the length of the mudstone section to be plugged should be more than 15 meters longer than the length of the mudstone section. The upper and lower connecting casings of the two plugs should be at least 10 meters long.

[0092] 3. Set up the completion string, tubing assembly: guide shoe + well wash valve + casing + first packer 9 + casing + first packer 9 + casing + screen pipe + first packer 9 + casing + first packer 9 + casing + screen pipe + aluminum alloy blind flange + casing + middle packer + staged clamp + casing string + glass blind flange + casing to wellhead; the section between the aluminum alloy blind flange and the glass blind flange is an air section, without mud filling;

[0093] 4. The glass blind plate is broken by pressure.

[0094] 5. Static venting, static venting, mud and air replacement;

[0095] 6. Grouting: Grouting and venting are carried out simultaneously to remove all air from the wellhead and fill it with mud.

[0096] 7. Pressure-expanding packer;

[0097] 8. Continue pressing to open the graded clamp.

[0098] 9. Circulate the mud and adjust its properties;

[0099] 10. In the half-cycle cementing process, the mud flows from the wellhead through the casing to the stage collar, and then returns from the stage collar to the wellhead. The annulus from the stage collar to the wellhead is completely filled with cement sheath.

[0100] 11. Press and close the graded clamps, then wait for the mixture to solidify;

[0101] 12. Measuring cementing quality;

[0102] 13. Drill out residual cement plugs, staged hoop accessories, aluminum alloy blind flanges, etc. in the wellbore, and ensure that the borehole diameter is not less than 118mm;

[0103] 14. Connect the well-washing pipe string according to the location and depth of the well-washing valve. The well-washing pipe string is a conventional well-washing pipe string.

[0104] 15. Run the well tubing string down and complete the acid washing;

[0105] 16. After acid washing, the packer expansion tube string is connected according to the number and location of the packers. The tube string combination is as follows: guide shoe + tubing + K344 packer + tubing + throttle valve + tubing + K344 packer + tubing + K344 packer + tubing + throttle valve + tubing + K344 packer + tubing to the wellhead;

[0106] 17. Start the pump and activate the throttle valve at the wellhead;

[0107] 18. Using the throttle valve to cut off the pressure difference, start the K344 packer to close the annulus between the oil pipe and the packer;

[0108] 19. Pressure-sealed packer;

[0109] 20. Depressurize, reset K344 packer, and remove the expansion seal string;

[0110] 21. Install the wellhead and begin trial production.

[0111] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0112] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.

Claims

1. A method for early sand control and well completion construction of horizontal wells, characterized in that, include: S1. Prepare wellbore (2), wherein wellbore (2) is a horizontal well, and wellbore (2) includes a vertical section, a directional section and a horizontal section, wherein the horizontal section includes a reservoir section and a mudstone section; S2. A solidified well casing string is run into the wellbore (2). The solidified well casing string includes an upper structure, a middle packer (6) and a lower structure connected in sequence. The upper structure includes a casing string (3) and a graded collar (5) directly connected to the middle packer (6). The lower structure includes a first blind plate (7) connected to the middle packer (6), a screen pipe (8) corresponding to the reservoir section and a sand-proof casing (14) corresponding to the mudstone section, and a first packer group. The first packer group includes two first packers (9) corresponding to the two ends of the mudstone section. S3. Pressurize the solidified well casing string to expand and seal the middle packer (6); continue pressurizing to open the stage collar (5) and inject mud into the solidified well casing string so that the mud solidifies in the annulus between the casing string (3) and the wellbore (2); S4. Drill through the graded clamp (5) and the first blind plate (7), and insert an expansion sealing string into the solidified well string. The expansion sealing string includes an oil pipe (13) and a second packer group corresponding to the first packer group. The second packer group includes two second packers (11). S5. Pressurize the expansion sealing string so that the second packer (11) expands and seals in the solidified well string to seal the annulus between the expansion sealing string and the first packer group, and further cause the first packer (9) to expand and seal in the wellbore (2) to seal the annulus between the sand-proof casing (14) and the mudstone section.

2. The method for early sand control and well completion construction of horizontal wells according to claim 1, characterized in that, The casing string (3) is provided with a second blind plate (4) located in the directional section. There is an air section between the second blind plate (4) and the first blind plate (7). The area above the second blind plate (4) is filled with mud. In S3, mud is injected into the solidified well string to expel the air between the second blind plate (4) and the first blind plate (7), so that the mud circulates and flows to adjust its performance.

3. The method for early sand control and well completion construction of horizontal wells according to claim 2, characterized in that, In S3, after the stage clamp (5) is closed by pressure, wait for the mud in the annulus of the casing string (3) and the wellbore (2) to solidify.

4. The method for early sand control and well completion construction of horizontal wells according to claim 1, characterized in that, The length of the sand-proof sleeve (14) is greater than the length of the mudstone section.

5. The method for early sand control and well completion construction of horizontal wells according to claim 1, characterized in that, The screen tube (8) and the first packer (9) are connected by a sleeve.

6. The method for early sand control and well completion construction of horizontal wells according to claim 1, characterized in that, The lower structure is provided with a first guide shoe (12) at its end.

7. The method for early sand control and well completion construction of horizontal wells according to claim 1, characterized in that, The distance between the second packer group is greater than the distance between the first packer group, and the two first packers (9) are disposed between the two second packers (11).

8. The method for early sand control and well completion construction of horizontal wells according to claim 1, characterized in that, A throttle valve (15) is provided between the two second packers (11).

9. The method for early sand control and well completion construction of horizontal wells according to claim 1, characterized in that, The end of the expansion-sealing tube string is provided with a second guide shoe (16).

10. The method for early sand control and well completion construction of horizontal wells according to claim 1, characterized in that, Also includes: S6, depressurize to allow the second packer (11) to contract and release the expansion seal string.

11. The method for early sand control and well completion construction of horizontal wells according to claim 10, characterized in that, The second packer (11) is a reversible packer, while the first packer (9) and the middle packer (6) are irreversible packers.

12. The method for early sand control and well completion construction of horizontal wells according to claim 1, characterized in that, The solidified well string is equipped with a well-washing valve (10). In S4, before the expansion sealing string is lowered, the well-washing string is lowered and the well-washing operation is performed.

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