A reservoir cementing tool and its application method

Abstract

This invention discloses a reservoir-around cementing tool, comprising: an upper double-wall packer and a lower double-wall packer fixedly connected to a double-wall casing assembly, with the upper and lower double-wall packers spaced apart axially along the double-wall casing assembly; the double-wall casing includes an inner casing and an outer casing; the upper double-wall packer includes a first inner sealing tube and a first core tube sleeved outside the first inner sealing tube and concentrically arranged with the first inner sealing tube; a first annular space is formed between the first inner sealing tube and the first core tube; an upper packer rubber sleeve assembly is sleeved on the outer wall of the first core tube, and an expandable second annular space is formed between the upper packer rubber sleeve assembly and the first core tube. This invention also discloses a method of using the reservoir-around cementing tool. The reservoir-around cementing tool and its method of use of this invention combine expandable packer technology and double-wall casing technology, utilizing a packer rubber sleeve to seal the reservoir, while cement slurry circulates through the annular channel of the double-wall casing, preventing contact between the cement slurry and the reservoir.

Description

Technical Field

[0001] This invention relates to cementing tools for oil and gas, and more specifically, to a reservoir-around cementing tool and its method of use. Background Technology

[0002] Cementing in oil and gas wells is the process of running casing into the well and injecting cement into the annular space between the wellbore and the casing. Cementing is a crucial operation in the drilling process. Generally, at least two cementing operations are required (for production wells), and up to four or five cementing operations (for deep exploration wells).

[0003] In the cementing process of oil and gas wells, reservoir contamination by cement slurry has always been a difficult problem to overcome. Currently, most domestic and international methods involve optimizing the performance of cement slurry to reduce the penetration of cement slurry filtrate into the reservoir, thereby achieving the goal of reducing reservoir contamination.

[0004] In existing technologies, specially designed tools can be used to bypass the reservoir, thus preventing contamination of the reservoir by the cement slurry, with more significant effects. However, existing technologies are only suitable for thinner reservoirs, and the tools mostly use single-layer pipes.

[0005] Therefore, researching and designing a cementing tool that is suitable for reservoirs of various thicknesses has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a reservoir cementing tool and its usage method.

[0007] The reservoir cementing tool disclosed in this embodiment of the invention includes: an upper double-wall packer, a double-wall casing assembly, and a lower double-wall packer;

[0008] The upper double-wall packer and the lower double-wall packer are fixedly connected to the double-wall sleeve assembly, and the upper double-wall packer and the lower double-wall packer are spaced apart along the axial direction of the double-wall sleeve assembly;

[0009] One end of the double-walled sleeve assembly is connected to the upper double-walled packer, and the other end is connected to the lower double-walled packer;

[0010] The double-walled sleeve assembly includes at least one double-walled sleeve, the double-walled sleeve including an inner sleeve and an outer sleeve, the inner sleeve being sleeved inside the outer sleeve and the inner sleeve and the outer sleeve being concentrically arranged;

[0011] The upper double-wall packer includes a first inner sealing tube and a first core tube sleeved outside the first inner sealing tube and concentrically arranged with the first inner sealing tube; a first annular space is formed between the first inner sealing tube and the first core tube; an upper packer rubber sleeve assembly is sleeved on the outer wall of the first core tube, and an expandable second annular space is formed between the upper packer rubber sleeve assembly and the first core tube.

[0012] Furthermore, the lower double-wall packer includes a second inner sealing tube and a second core tube sleeved outside the second inner sealing tube and concentrically arranged with the second inner sealing tube; a third annular space is formed between the second inner sealing tube and the second core tube; a lower packer rubber sleeve assembly is sleeved on the outer wall of the second core tube, and an expandable fourth annular space is formed between the lower packer rubber sleeve assembly and the second core tube, the lower packer rubber sleeve assembly including a lower packer rubber sleeve.

[0013] Furthermore, in the double-walled sleeve, a fifth annular space is formed between the outer sleeve and the inner sleeve; when the upper packer sleeve assembly and the lower packer sleeve assembly expand outward, the liquid can flow through the first annular space, the fifth annular space and the third annular space.

[0014] Furthermore, the double-wall sleeve assembly includes at least two double-wall sleeves and a coupling for fixing the connection between two adjacent double-wall sleeves.

[0015] Furthermore, one end of the double-walled sleeve assembly is inserted into the lower end of the upper double-walled packer and connected by a coupling, and the upper end of the lower double-walled packer is inserted into the other end of the double-walled sleeve assembly and connected by a coupling.

[0016] Furthermore, the upper double-wall packer also includes a valve system connector;

[0017] The valve system connector has an annular stepped surface inside. The upper end of the first inner sealing tube is sealed and connected to the annular stepped surface. The upper end of the first core tube is inserted into the lower end of the valve system connector and threaded.

[0018] Furthermore, the outer diameter of the lower end of the first core tube is larger than the outer diameter of the upper end of the first core tube, and a sloped transition portion is formed between the lower end and the upper end of the first core tube.

[0019] Furthermore, the lower end of the first inner sealing tube is attached to the inner wall of the lower end of the first core tube by a straightening block provided on the outer wall of the first inner sealing tube, and a C-shaped retaining ring is provided at the lower end of the straightening block to restrict the axial movement of the first inner sealing tube.

[0020] Furthermore, the upper packer rubber sleeve assembly includes an upper protective sleeve, a lower protective sleeve, and an upper packer rubber sleeve disposed between the upper and lower protective sleeves; wherein, the upper protective sleeve is connected to the lower end of the valve system connector, and the lower protective sleeve is connected to the first core tube via a beveled transition portion adjacent to the first core tube.

[0021] This invention also discloses a method for using the reservoir cementing tool as described above, comprising the following steps:

[0022] 1) First install the lower double-wall packer, then connect the double-wall casing assembly, then connect the upper double-wall packer, and finally connect the upper tubing string to the wellhead;

[0023] 2) During use, by pressurizing the wellhead, the liquid enters the second annular space of the upper double-wall packer and the fourth annular space of the lower double-wall packer through the valve system connector, squeezing the upper packer rubber sleeve assembly and the lower packer rubber sleeve assembly to expand towards the well wall, thereby achieving a sealed fit between the upper double-wall packer, the lower double-wall packer and the well wall.

[0024] 3) After the upper packer rubber sleeve assembly and the lower packer rubber sleeve assembly are expanded and sealed, the fluid can only flow from inside the reservoir cementing tool; wherein, when the fluid passes through the reservoir cementing tool, it can only flow into the fifth annulus space of the double-wall casing assembly through the lower double-wall packer, and flow out of the reservoir cementing tool through the upper double-wall packer.

[0025] By adopting the above technical solution, the present invention has at least the following beneficial effects:

[0026] The present invention discloses a reservoir cementing tool and its usage method, which combines expandable packer technology and double-wall casing technology. It uses a packer sleeve to seal the reservoir, and the cement slurry circulates through the annular channel of the double-wall casing to avoid contact between the cement slurry and the reservoir. At the same time, the number and length of the double-wall casing can be adjusted according to the reservoir thickness, making on-site installation convenient and highly operable. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the upper double-walled packer according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the lower double-wall packer according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of the double-walled sleeve according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of the reservoir cementing tool according to an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the cross-section of the straightening block according to an embodiment of the present invention;

[0033] Figure 6 yes Figure 1 A partially enlarged schematic diagram of the installation of the first inner sealing tube and the fixing method of the retaining ring.

[0034] [List of Labels in the Attached Image]

[0035] A1 Upper double-wall packer, A2 Double-wall bushing, A3 Lower double-wall packer;

[0036] 1 Valve connector, 1-1 Body, 1-2 Valve component, C1 First circulation hole, 1-3 First hydraulic passage, 1-4 Seal, 1-5 Annular stepped surface, 1-6 Second hydraulic passage;

[0037] 2 First inner sealing tube, 3 First core tube, 2-2 straightening block, 2-1 sealing slot, 2-3 C-type retaining ring, 3-1 First annular space, 3-2 Second annular space;

[0038] 4 Upper packer rubber sleeve assembly, 4-1 Upper protective sleeve, 4-2 Upper packer rubber sleeve, 4-3 Lower protective sleeve;

[0039] 5. Sealing end ring; 6. Coupling;

[0040] 7 Second inner sealing tube, 7-1 Plug part, 7-2 Straightening block, 7-3 Second core tube, 7-4 Lower packer rubber sleeve assembly, C2 Second circulation hole, 7-5 Third annular space, 7-6 Fourth annular space;

[0041] 8 Inner sleeve, 9 Outer sleeve, 8-2 Straightening block, 8-3 Elastic retaining ring, 8-4 Sealing slot, 8-5 Plug part, 8-6 Fifth ring space, 10 Coupling;

[0042] T - upper end, B - lower end. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0044] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0045] In the following description of this embodiment, the upper end T (or upper part, above) and the lower end B (or lower part, below) of the component refer to the end of the component that is closer to the wellhead after it is lowered into the well as the upper end, and the end that is closer to the bottom of the well as the lower end (e.g., ...). Figure 4 (As shown).

[0046] In the following description of this embodiment, the same sub-components in different components are referred to by different reference numerals for clarity.

[0047] See Figure 4 As shown, this embodiment provides a reservoir cementing tool, including: an upper double-wall packer A1, a double-wall casing A2 assembly, and a lower double-wall packer A3;

[0048] The upper double-wall packer A1 and the lower double-wall packer A3 are fixedly connected to the double-wall sleeve A2 assembly, and the upper double-wall packer A1 and the lower double-wall packer A3 are spaced apart along the axial direction of the double-wall sleeve A2 assembly;

[0049] One end of the double-walled sleeve A2 assembly is connected to the upper double-walled packer A1, and the other end is connected to the lower double-walled packer A3;

[0050] The double-walled sleeve A2 assembly includes at least one double-walled sleeve A2, which includes an inner sleeve and an outer sleeve, with the inner sleeve fitted inside the outer sleeve and the inner sleeve and the outer sleeve being concentrically arranged.

[0051] The upper double-wall packer A1 includes a first inner sealing tube 2 and a first core tube 3 that is sleeved outside the first inner sealing tube 2 and concentrically arranged with the first inner sealing tube 2; a first annular space 3-1 is formed between the first inner sealing tube 2 and the first core tube 3; an upper packer rubber sleeve assembly 4 is sleeved on the outer wall of the first core tube 3, and an expandable second annular space 3-2 is formed between the upper packer rubber sleeve assembly 4 and the first core tube 3.

[0052] Specifically, such as Figure 4The shown reservoir-around cementing tool includes only one double-walled casing A2. Since the location of the double-walled casing A2 corresponds to the reservoir location, the number and length of each double-walled casing A2 can be adaptively adjusted according to the reservoir thickness. The maximum length of a single double-walled casing A2 can reach 12m. In other preferred embodiments, the reservoir thickness is greater than in this embodiment, and the number of double-walled casing A2s in the assembly can be two, three, four, etc., with adjacent double-walled casing A2s fixedly connected by couplings.

[0053] In an optional embodiment, the upper double-wall packer A1 further includes a valve system connector 1.

[0054] Specifically, such as Figure 1 As shown, the upper double-wall packer A1 mainly includes a valve system connector 1, a first inner sealing tube 2, a first core tube 33, an upper packer rubber sleeve assembly 4, a sealing end ring 5, and a coupling 6. The valve system connector 1 mainly consists of a body 1-1, valve components 1-2, a first circulation hole C1, a first hydraulic channel 1-3, and a second hydraulic channel 1-6. The first circulation hole C1 consists of multiple circular through holes evenly distributed around the circumference of the valve system connector 1. The first circulation hole C1 communicates with the first annular space 3-1 between the first circulation hole C1 and the first inner sealing tube 2 and the first core tube 3, and with the annular space between the upper double-wall packer A1 and the well wall. The valve system connector 1 has pressure transmission holes drilled in it, and valve components 1-2 are installed inside these holes. Specifically, these can be filters, pressure relief valves, check valves, and locking valves. The first circulation hole C1 must avoid the location of the pressure transmission holes to prevent cross-contamination. The packer valve system inlet is open, with one end connected to the interior of the upper double-walled packer A1 and the other end perpendicularly connected to the pressure transmission channel of valve 1-2. The pressure transmission channel of valve 1-2 is connected to the expandable second annular space 3-2 between the upper packer rubber sleeve assembly 4 and the first core tube 3. After wellhead pressurization, cement enters the second annular space 3-2, and under the pressure of the cement, the upper packer rubber sleeve of the upper packer rubber sleeve assembly 4 expands towards the well wall. The installation position and angle of valve 1-2 are related to the size of valve system connector 1. The expansion process of the upper packer rubber sleeve in this embodiment is a method and structure conventionally used in the art, and will not be described in detail here.

[0055] In an optional embodiment, the valve system connector 1 has an annular stepped surface 1-5 inside, the upper end of the first inner sealing tube 2 is sealed and connected to the annular stepped surface, and the upper end of the first core tube 3 is inserted into the lower end of the valve system connector 1 and threaded.

[0056] In an optional embodiment, the outer diameter of the lower end of the first core tube 3 is larger than the outer diameter of the upper end of the first core tube 3, and a sloped transition portion is formed between the lower and upper ends of the first core tube 3. The lower end of the first core tube 3 is connected to the coupling via a sleeve thread. The lower end of the first core tube 3 is referred to as the wide-diameter portion, and the upper end of the first core tube 3 is referred to as the narrow-diameter portion.

[0057] Specifically, such as Figure 1 As shown, the valve system connector 1 is a cylindrical hollow component. The inner diameter of the middle part of the valve system connector 1 is larger than the inner diameter of the lower end of the valve system connector 1. Therefore, a continuous annular stepped surface 1-5 is formed between the middle part and the lower end of the valve system connector 1. The upper end of the first inner sealing tube 2 rests on the annular stepped surface, and this annular stepped surface has two sealing grooves. The sealing element 1-4 is disposed in the sealing groove, so that the upper end of the first inner sealing tube 2 is sealed and connected to the annular stepped surface. The upper end of the first core tube 3 is inserted into the lower end of the valve system connector 1 and threaded. In order to achieve a tight seal, two sealing grooves are also provided at the contact position between the lower end of the valve system connector 1 and the upper end of the first core tube 3. The sealing element 1-4 is disposed in the sealing groove.

[0058] In an optional embodiment, the lower end of the first inner sealing tube 2 is fitted with the inner wall of the lower end of the first core tube 3 by a straightening block 2-2 disposed on the outer wall of the first inner sealing tube 2, and a C-shaped retaining ring 2-3 is disposed at the lower end of the straightening block 2-2 to restrict the axial movement of the first inner sealing tube 2.

[0059] Specifically, such as Figure 1 As shown, one end of the first inner sealing tube 2 is installed in a sealing fit with the stepped surface of the valve system connector 1 through the sealing element 1-4, and its axial movement is restricted by the step. The other end of the first inner sealing tube 2 is attached to the inner wall of the first core tube 3 through the straightening block 2-2, and its axial movement is restricted by the C-type retaining ring 2-3 (e.g., Figure 6 (As shown). The first inner sealing tube 2 is also provided with a sealing slot 2-1 for installing a sealing ring. After the sealing ring is installed, the sealing slot 2-1 can be sealed to the upper end of the inserted double-wall sleeve A2.

[0060] In an optional embodiment, the upper packer rubber sleeve assembly 4 includes an upper protective sleeve 4-1, a lower protective sleeve 4-3, and an upper packer rubber sleeve 4-2 disposed between the upper protective sleeve 4-1 and the lower protective sleeve 4-3; wherein, the upper protective sleeve 4-1 is connected to the lower end of the valve system connector 1, and the lower protective sleeve 4-3 is connected to the first core tube 33 via a sloped transition portion adjacent to the first core tube 3.

[0061] Specifically, such as Figure 1 As shown, the lower protective sleeve 4-3 of the upper packer sleeve assembly 4 is connected to the first core tube 3 via a sealing end ring 5. The sealing end ring 5 is installed on the smooth cylindrical surface of the inclined transition section adjacent to the first core tube 3 by welding, with the welding point closer to the lower end of the first core tube 3. The upper packer sleeve assembly 4 is installed on the outside of the narrow diameter section of the first core tube 3.

[0062] In an optional embodiment, the lower double-wall packer A3 includes a second inner sealing tube 7 and a second core tube 7-3 sleeved outside the second inner sealing tube 7 and concentrically arranged with the second inner sealing tube 7; a third annular space 7-5 is formed between the second inner sealing tube 7 and the second core tube 7-3; a lower packer rubber sleeve assembly 7-4 is sleeved on the outer wall of the second core tube 7-3, and an expandable fourth annular space is formed between the lower packer rubber sleeve assembly 7-4 and the second core tube 7-3.

[0063] The lower packer rubber sleeve assembly includes an upper protective sleeve, a lower protective sleeve, and a lower packer rubber sleeve disposed between the upper and lower protective sleeves; wherein, the upper protective sleeve is connected to the lower end of the valve system connector, and the inclined transition portion of the lower protective sleeve adjacent to the second core tube is connected to the second core tube.

[0064] The lower end of the second inner sealing tube 7 is attached to the inner wall of the lower end of the second core tube 7-3 by a straightening block 7-2 set on the outer wall of the second inner sealing tube 7.

[0065] Specifically, Figure 2 The lower double-walled packer A3 is shown. (By...) Figure 1 and Figure 2 As can be seen, the upper double-wall packer A1 and the lower double-wall packer A3 share most of the same structure. The difference between them lies in the structure of their inner sealing tubes. The lower end of the first inner sealing tube 2 in the upper double-wall packer A1 is a slot, while the upper end of the second inner sealing tube in the lower double-wall packer A3 is a plug 7-1. Therefore, the components identical to those in the lower double-wall packer A3 and the upper double-wall packer A1 will not be described here, and their expansion sealing process is also the same. The upper double-wall packer A1 and the lower double-wall packer A3 are installed axially symmetrically.

[0066] In an optional embodiment, a fifth annular space 8-6 is formed between the outer sleeve 9 and the inner sleeve 8 in the double-walled sleeve A2. When the upper packer sleeve assembly 4 and the lower packer sleeve assembly expand outward, the liquid can enter the fifth annular space 8-6 through the first annular space 3-1, and then enter the third annular space 7-5 through the fifth annular space 8-6. The liquid in this embodiment is cement slurry.

[0067] In an optional embodiment, one end of the double-walled sleeve A2 assembly is inserted into the lower end of the upper double-walled packer A1 and connected by a coupling 6, while the upper end of the lower double-walled packer A3 is inserted into the other end of the double-walled sleeve A2 assembly and connected by a coupling 10.

[0068] Specifically, such as Figure 3As shown, the double-walled sleeve A2 mainly includes an inner sleeve 8 and an outer sleeve 9. The inner sleeve 8 and the outer sleeve 9 are installed coaxially, and both ends of the inner sleeve 8 are attached to the steps of the outer sleeve 9 by straightening blocks 8-2, and the straightening blocks 8-2 are limited by elastic retaining rings 8-3 to limit the axial direction of the inner sleeve 8. One end of the double-walled sleeve A2 is a plug part 8-5 that mates with the sealing slot 2-1 of the upper double-walled sleeve A2, and the other end of the double-walled sleeve A2 is a sealing slot 8-4 that mates with the plug part 7-1 of the lower double-walled sleeve A2. The plug parts 7-1 and 8-5 are cylindrical bosses with a high degree of smoothness. The slots 2-2 and 8-4 are cylindrical grooves with a high degree of smoothness.

[0069] like Figure 5 The straightening block 2-2 shown is a series of milled cylindrical bosses evenly distributed around its circumference. Similarly, straightening blocks 7-2, 8-1, and 8-2 have the same structure.

[0070] This embodiment also discloses a method for using the above-mentioned reservoir cementing tool, including the following steps:

[0071] 1) First install the lower double-wall packer A3, then connect the double-wall casing A2 assembly, then connect the upper double-wall packer A1, and finally connect the upper tubing string to the wellhead;

[0072] 2) During use, by pressurizing the wellhead, the liquid enters the second annular space 3-2 of the upper double-wall packer A1 and the fourth annular space of the lower double-wall packer A3 through the valve system connector 1, which squeezes the rubber sleeves of the upper packer 4-2 and the lower packer to expand into the formation, thereby achieving a sealed fit between the rubber sleeves of the upper double-wall packer A1 and the lower packer and the well wall.

[0073] 3) After the upper packer rubber sleeve assembly 4 and the lower packer rubber sleeve assembly are expanded and sealed, the liquid can only flow from inside the reservoir cementing tool; wherein, when the liquid passes through the reservoir cementing tool, it can only flow into the fifth annulus space of the double-wall casing A2 assembly through the lower double-wall packer A3, and flow out of the reservoir cementing tool through the upper double-wall packer A1.

[0074] Specifically, the method for using cementing tools around the reservoir is as follows: First, install the lower double-wall packer A3 according to the tubing string design. Then, connect a certain number of double-wall casings A2 according to the reservoir thickness. Next, connect the upper double-wall packer A1, and finally connect the upper tubing string to the wellhead. When the tool needs to function, through wellhead pressure, fluid flows through hydraulic channel 1-3, through valve system 1-1 and valve system channels, and enters the gap between the upper packer rubber sleeve assembly 4 and the first core tube 33, squeezing the upper packer rubber sleeve 4-2 outward to achieve a sealed fit between the upper packer rubber sleeve 4-2 and the well wall.

[0075] Before the upper packer sleeve assembly 4 and the lower packer sleeve assembly are expanded and sealed, the fluid circulation channels include the annular space between the upper double-walled packer A1 and the lower double-walled packer A3 and the wellbore, the first annular space 3-1 of the upper double-walled packer A1, and the fourth annular space of the lower packer sleeve assembly. After the upper packer sleeve assembly 4 and the lower packer sleeve assembly are expanded and sealed, the annular space between the upper double-walled packer A1 and the lower double-walled packer A3 and the wellbore is sealed and isolated. When the fluid passes through the cementing tool around the reservoir, it can only flow into the fifth annular space between the inner and outer sleeves 9 through the second circulation hole C2 of the lower double-walled packer A3, and flow out from the first circulation hole C1 of the upper double-walled packer A1 and enter the upper wellbore annulus. It cannot flow into the annulus between the upper double-walled packer A1 and the lower double-walled packer A3 and the wellbore, thus achieving the purpose of protecting the reservoir.

[0076] The upper double-wall packer A1 and the lower double-wall packer A3 adopt a split structure, which is convenient for on-site installation. The number of double-wall casings A2 can be selected according to the reservoir thickness, and the number of cementing tools around the reservoir can be selected according to the number of reservoirs. An annular space or annular channel refers to the annular channel for fluid flow between two tubing strings or between the tubing string and the wellbore.

[0077] The equivalent diameter of the annular gaps in the first annular space 3-1, the third annular space, and the fifth annular space is not less than 70 mm. The inner and outer sleeves 9 are coaxially installed using an intermittent fit, and are sealed together by seals after assembly. The centering block improves the centering of the inner tube. The thickness of the upper packer rubber sleeve 4-2 and the lower packer rubber sleeve is greater than 18 mm, and their length is greater than 1.5 m. The first circulation hole C1 and the second circulation hole are multiple circumferentially distributed circular through holes, communicating with the annulus between the inner and outer tubes and the annulus between the tool and the wellbore. The equivalent diameter of the first circulation hole C1 and the second circulation hole is not less than 70 mm.

[0078] The sealing element used in this embodiment is preferably a sealing ring commonly used in the art, such as an NBR nitrile rubber sealing ring.

[0079] Specifically, a more detailed explanation of the application method for the cementing process around the reservoir:

[0080] (1) Install the lower double-wall packer A3 according to the pipe string design;

[0081] (2) Then connect a certain number of double-walled casings A2 according to the reservoir thickness;

[0082] (3) Further connect the upper double-walled packer A1;

[0083] (4) Connect the upper pipe string to the wellhead;

[0084] (5) Start the pump to circulate and record the circulation pressure P1;

[0085] (6) When cementing tools around the reservoir are needed to function, a pressure-binding tool is deployed at the wellhead. The pressure-binding tool can be a ball or a rubber plug.

[0086] (7) Pressurize to the design pressure and stabilize for 15-20 minutes;

[0087] (8) Liquid flows through the hydraulic channel through the valve system and valve system channel, enters the gap between the upper packer rubber sleeve assembly 4 and the first core tube 3 and the lower packer rubber sleeve assembly and the second core tube, squeezes the rubber sleeve to expand outward, and achieves a sealed fit with the well wall.

[0088] (9) Continue pressing until the pressing device falls off, open the circulation channel, and record the circulation pressure P2. The pressing device can be a ball seat or a rubber stopper seat.

[0089] (10) If P2-P1 = 1MPa, then it is determined that the upper double-wall packer A1 and the lower double-wall packer A3 are expanded and sealed, and the annular space between the upper double-wall packer A1 and the lower double-wall packer A3 and the well wall is closed; otherwise, the setting fails and other remedial measures are taken.

[0090] The packer valve system inlet is open, with one end connected to the interior of the tool and the other end having a vertically penetrating pressure transmission channel for the valve system. The flow diameter of the hydraulic channel is not less than 6 mm.

[0091] The packer rubber sleeve assembly consists of upper and lower protective sleeves 4-3 and a rubber sleeve. The protective sleeve is a metal support ring, and the rubber sleeve contains an inner sealing cylinder, a steel sheet, and an outer rubber sleeve.

[0092] The minimum distance between the mounting hole of valve 1-2 and body 1-1 shall not be less than 5mm.

[0093] When there are multiple reservoirs, multiple reservoir cementing tools need to be used, and the same pressure is used for their sealing and expansion.

[0094] It should be noted that the components or steps in the above embodiments can be interchanged, substituted, added, or deleted. Therefore, the combinations formed by these reasonable permutations and transformations should also fall within the protection scope of this invention, and the protection scope of this invention should not be limited to the above embodiments.

[0095] The above are exemplary embodiments disclosed in this invention. The order of the disclosed embodiments is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. However, it should be noted that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of this invention (including the claims) is limited to these examples. Various changes and modifications can be made without departing from the scope defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular.

[0096] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of the different aspects of the invention as described above exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A reservoir cementing tool, characterized in that, include: Upper double-wall packer, double-wall sleeve assembly and lower double-wall packer; The upper double-wall packer and the lower double-wall packer are fixedly connected to the double-wall sleeve assembly, and the upper double-wall packer and the lower double-wall packer are spaced apart along the axial direction of the double-wall sleeve assembly; One end of the double-walled sleeve assembly is connected to the upper double-walled packer, and the other end is connected to the lower double-walled packer; The double-walled sleeve assembly includes at least one double-walled sleeve, which includes an inner sleeve and an outer sleeve. The inner sleeve is fitted inside the outer sleeve and the inner sleeve and the outer sleeve are concentrically arranged. The two ends of the inner sleeve are attached to the steps of the outer sleeve by straightening blocks and the straightening blocks are limited by elastic retaining rings to realize the axial positioning of the inner sleeve. A fifth annular space is formed between the outer sleeve and the inner sleeve, and the equivalent diameter of the annular gap of the fifth annular space is not less than 70 mm. The upper double-wall packer includes a first inner sealing tube, a first core tube sleeved outside the first inner sealing tube and concentrically arranged with the first inner sealing tube, and a valve system connector. A first annular space is formed between the first inner sealing tube and the first core tube; the lower end of the first inner sealing tube is attached to the inner wall of the lower end of the first core tube by a straightening block provided on the outer wall of the first inner sealing tube, and a C-shaped retaining ring is provided at the lower end of the straightening block to restrict the axial movement of the first inner sealing tube. An upper packer rubber sleeve assembly is fitted onto the outer wall of the first core tube, forming an expandable second annular space between the upper packer rubber sleeve assembly and the first core tube; the upper packer rubber sleeve assembly includes an upper protective sleeve, a lower protective sleeve, and an upper packer rubber sleeve disposed between the upper and lower protective sleeves; the outer diameter of the lower end of the first core tube is larger than the outer diameter of the upper end of the first core tube, and a sloped transition portion is formed between the lower and upper ends of the first core tube; wherein, the upper protective sleeve is connected to the lower end of the valve system connector, and the lower protective sleeve is connected to the first core tube near the sloped transition portion of the first core tube; The thickness of the upper packer rubber cylinder is greater than 18mm and the length is greater than 1.5m.

2. The reservoir-around cementing tool according to claim 1, characterized in that, The lower double-wall packer includes a second inner sealing tube and a second core tube sleeved outside the second inner sealing tube and concentrically arranged with the second inner sealing tube; a third annular space is formed between the second inner sealing tube and the second core tube; a lower packer rubber sleeve assembly is sleeved on the outer wall of the second core tube, and an expandable fourth annular space is formed between the lower packer rubber sleeve assembly and the second core tube.

3. The reservoir-around cementing tool according to claim 2, characterized in that, When the upper packer sleeve assembly and the lower packer sleeve assembly expand outward, the liquid can flow through the first annular space, the fifth annular space and the third annular space.

4. The reservoir-around cementing tool according to claim 1, characterized in that, The double-wall sleeve assembly includes at least two double-wall sleeves and a coupling for fixing the connection between two adjacent double-wall sleeves.

5. The reservoir-around cementing tool according to claim 1, characterized in that, One end of the double-walled sleeve assembly is inserted into the lower end of the upper double-walled packer and connected by a coupling, and the upper end of the lower double-walled packer is inserted into the other end of the double-walled sleeve assembly and connected by a coupling.

6. The reservoir-around cementing tool according to claim 1, characterized in that, The valve system connector has an annular stepped surface inside. The upper end of the first inner sealing tube is sealed and connected to the annular stepped surface. The upper end of the first core tube is inserted into the lower end of the valve system connector and threaded.

7. A method of using a reservoir cementing tool as described in any one of claims 1-6, characterized in that, Includes the following steps: 1) First install the lower double-wall packer, then connect the double-wall casing assembly, then connect the upper double-wall packer, and finally connect the upper tubing string to the wellhead; 2) During use, by pressurizing the wellhead, the liquid enters the second annular space of the upper double-wall packer and the fourth annular space of the lower double-wall packer through the valve system connector, squeezing the upper packer rubber sleeve assembly and the lower packer rubber sleeve assembly to expand towards the well wall, thereby achieving a sealed fit between the upper double-wall packer, the lower double-wall packer and the well wall. 3) After the upper packer rubber sleeve assembly and the lower packer rubber sleeve assembly are expanded and sealed, the fluid can only flow from inside the reservoir cementing tool; wherein, when the fluid passes through the reservoir cementing tool, it can only flow into the fifth annulus space of the double-wall casing assembly through the lower double-wall packer, and flow out of the reservoir cementing tool through the upper double-wall packer.

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