An integrated fracturing and production tubing string for open-hole horizontal wells and its application method
By using an integrated fracturing and production string for open-hole horizontal wells, which combines fracturing and filling with production and mining functions, the problems of sand production risk and high construction costs in the segmented fracturing and filling technology of open-hole horizontal wells are solved. This enables effective segmented sand control and selective mining of the wellbore, and improves the initial production capacity after well completion.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA NAT OFFSHORE OIL CORP
- Filing Date
- 2024-08-05
- Publication Date
- 2026-05-26
AI Technical Summary
In existing technologies, the open-hole horizontal well segmented fracturing and filling technology cannot effectively prevent sand production in segments, which poses a risk of sand production. It also has high construction costs and cannot meet the needs of long horizontal wells and well conditions with low formation fracture pressure, resulting in limited production capacity.
Design an integrated fracturing and production string for open-hole horizontal wells, combining fracturing and production functions. Through the combination of the central string and tool string, effective wellbore segmentation, sand control, and selective production are achieved. The open-hole packer and multi-layer screen structure reduce the risk of sand production and simplify the operation process.
It achieves effective segmented sand control in the wellbore, reduces the risk of sand production, increases initial production capacity after well completion, reduces construction costs, eliminates the need for additional sand control tubing and production tubing, simplifies the operation process, and improves work efficiency.
Smart Images
Figure CN118958936B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of oil and gas extraction technology, specifically relating to an integrated tubing string for fracturing and production in open-hole horizontal wells and its usage method. Background Technology
[0002] As some oilfields enter the mid-to-late stages of production, the water cut, production pressure differential, and fluid production intensity continue to increase, exacerbating sand production problems and making screen blockage increasingly serious. Gravel packing for sand control, as a widely used sand control completion method in recent years, has achieved good results, especially for open-hole horizontal wells, where it can significantly extend well completion life.
[0003] Horizontal well fracturing technology can effectively increase production, but it lacks long-term effective sand control measures, posing a risk of premature sand production in sand-producing reservoirs. Open-hole horizontal well packing sand control technology is currently the most commonly used method. Its principle is that sand-carrying fluid carries gravel into the annulus between the screen and the wellbore. After passing through the screen filter layer, the fluid returns to the surface via flushing, while the gravel remains in the annulus between the screen and the wellbore, providing support and sand control. However, open-hole horizontal well packing sand control has high requirements for the length of the open-hole section and formation fracturing pressure. It carries high construction risks in long horizontal wells or wells with low formation fracturing pressure, cannot meet the needs of layered sand control in horizontal wells, and requires secondary installation of layered production tubing for later refined layered production, resulting in high construction costs.
[0004] Sliding sleeve packer staged fracturing technology employs multi-stage packers for layered fracturing, with fracturing sleeves between the packers. The fracturing channels are provided by opening and closing these sleeves. The fracturing sleeves are typically opened using a ball-drop method. Each sleeve contains a ball seat, with the smallest ball seat installed in the lowest sleeve and the largest in the uppermost. Low-density fracturing balls of different sizes are dropped in and pumped to the corresponding ball seats. Pressure is then applied through the tubing to open the fracturing sleeve, fracturing the corresponding formation. Multiple layers of fracturing with a stationary tubing string can be completed in a single operation. However, sliding sleeve packer staged fracturing is only suitable for fracturing operations in low-to-medium permeability formations. It can only achieve fracturing-enhanced production and cannot effectively control sand in the wellbore. A dedicated sand-control tubing string must be run for sand control operations in the wellbore.
[0005] Therefore, it can be seen that the open-hole horizontal well segmented fracturing and filling technology in related technologies involves indiscriminate filling for sand control in open-hole horizontal wells, which cannot effectively segment the horizontal section. This can lead to premature water breakthrough in edge and bottom water reservoirs. For wells with long horizontal sections and low formation fracture pressure, the filling effect cannot be guaranteed, and there is a risk of premature sand production. Furthermore, the open-hole horizontal well segmented filling technology cannot achieve large-volume fracturing, resulting in limited initial production capacity. It requires a separate production tubing string, has a small wellbore diameter, and is difficult to process later. Additionally, it requires a separate lower completion production tubing string, making the operation complex and costly. Summary of the Invention
[0006] To address all or part of the aforementioned problems, the present invention aims to provide an integrated fracturing and production tubing string for open-hole horizontal wells and its usage method. This integrated fracturing and production functions enable effective segmented, sand-controlling, and selective production, ensuring filling effectiveness, reducing sand production risk, and increasing initial well completion productivity. Furthermore, it eliminates the need for additional sand-control tubing strings and separate production tubing strings, simplifying the operation process and reducing construction costs.
[0007] In a first aspect, the present invention provides an integrated fracturing production string for open-hole horizontal wells, including a central string and a tool string. The central string includes a top packer, a first sealing cylinder, a quick connector, a filling production assembly, a locking sealing assembly, and a float shoe assembly connected sequentially from top to bottom.
[0008] The filling production assembly is provided in multiple ways, and two adjacent filling production assemblies are connected by an open-eye packer. Each filling production assembly includes, from top to bottom, a circulating sliding sleeve, a first double-layer screen tube, a production sliding sleeve, a second double-layer screen tube, a second sealing cylinder, a filling sliding sleeve, and a positioning clamp.
[0009] The tool string includes, from top to bottom, a top setting tool, a test sealing rod, a reconnection rod, a reconnection tool, a filling control tool, a filling slide sleeve closing tool, a positioning tool, a filling slide sleeve switching tool, a circulating slide sleeve single-closing tool, a circulating slide sleeve single-opening tool, a positioning sealing rod, and a shearing slide sleeve;
[0010] The top setting tool is used to control the setting of the top packer. The test sealing rod is used to cooperate with the first sealing cylinder to achieve an annular seal between the central tube and the tool tube. The reconnection tool is used to connect with the reconnection rod, and the reconnection tool can cooperate with the locking sealing assembly to form a temporary lock. The filling control tool is used to control the opening and closing of its own flow channel. The positioning tool is used to cooperate with the positioning clamp to achieve the positioning of the central tube. The shearing sleeve is used to seal the bottom end of the tool tube.
[0011] Optionally, the locking and sealing assembly includes a locking cylinder and a third sealing cylinder. The third sealing cylinder is connected to the bottom of the locking cylinder. The locking cylinder is connected to the lowest positioning clamp. The locking cylinder can cooperate with the reconnection tool to achieve temporary locking.
[0012] Optionally, the floating shoe assembly includes a liquid-proof sealing cylinder and a floating shoe, wherein the liquid-proof sealing cylinder is connected to the bottom of the third sealing cylinder, and the floating shoe is connected to the bottom of the liquid-proof sealing cylinder.
[0013] Secondly, this invention provides a method for using an integrated fracturing production string in an open-hole horizontal well, comprising the following steps:
[0014] S1, connect the center tubing and the tool tubing, lower the center tubing into the wellbore, and lower the tool tubing into the center tubing;
[0015] S2, During the lowering of the tool string, external pressure equipment is used to pressurize the tool string and use liquid to flush out residual mud and sand in the open-hole horizontal section;
[0016] S3 controls the top packer to set;
[0017] S4, top packer seal inspection;
[0018] S5 controls multiple open-hole packers to be set separately, so that the multiple open-hole packers divide the wellbore into multiple zones from bottom to top;
[0019] S6, bottom-layer naked-eye packer seal inspection;
[0020] S7, verification of the closure of the sub-bottom layer filling sliding sleeve;
[0021] S8, fracturing and filling operations are carried out in the bottom area of the wellbore;
[0022] S9, reverse circulation well washing, to clean the residual slurry inside the wellbore;
[0023] S10, verification of bottom filling sliding sleeve closure;
[0024] S11, Raise the tool string to the corresponding layer of the oil well, and repeat steps S6-S10 until each layer of the oil well has completed fracturing and filling, reverse circulation well washing, and filling and sliding sleeve closure verification.
[0025] S12 controls the opening of the production and circulation sleeves at corresponding layers within the well via the tool string, enabling selective production and extraction of the oil well.
[0026] Alternatively, in S1:
[0027] The connection of the central tubing string includes: connecting the top packer to the first sealing cylinder, and connecting the float shoe to the locking cylinder from bottom to top; selecting the appropriate number of filling production assemblies according to the well depth; connecting two adjacent filling production assemblies through the open hole packer; connecting the locking cylinder to the lowest positioning joint collar; and connecting the quick connector to the uppermost circulating sleeve.
[0028] Ensure that the circulating sleeve, production sleeve and filling sleeve in each filling production assembly are in the closed state. Fill each first double-layer screen tube and second double-layer screen tube with liquid to ensure internal and external pressure balance. Perform pressure test on each filling production assembly to ensure connection sealing.
[0029] The connecting tool string includes: connecting the shearing sleeve to the reconnecting tool from bottom to top, and lowering it into the central string until the reconnecting tool and the locking cylinder form a temporary lock; then connecting the test sealing rod to the reconnecting rod and connecting the test sealing rod to the drill pipe; using the drill pipe to carry the test sealing rod and the reconnecting rod into the central string until the reconnecting rod and the reconnecting tool are connected; then lifting the tool string to unlock the reconnecting tool and the locking cylinder.
[0030] After the reconnection tool is unlocked, the tool string is pressure tested, and then the drill pipe is pressurized to the set pressure using an external pressure testing device to cut the shear pins in the shear sleeve, thereby achieving the connection between the tool string and the central string. Subsequently, the first sealing cylinder is connected to the quick connector, and the tool string is lowered.
[0031] Alternatively, in S2:
[0032] During the lowering of the tool string, external pressure equipment pressurizes the drill pipe, causing fluid to flow sequentially from the top setting tool to the shearing sleeve, then through the float shoe, and finally back out through the annulus between the central string and the wellbore to flush out residual mud and sand in the open-hole horizontal section.
[0033] Alternatively, in S3:
[0034] A steel ball of a set size is dropped, and the drill pipe is pressurized by an external pressurizing device until the steel ball shears and fills the ball seat in the filling control tool, so that the channel in the filling control tool is opened. Pressurization continues to the set pressure until the top packer is set. Then, pressurization continues to the set pressure to release the top setting tool from the top packer, thereby releasing the lock between the central tubing and the tool tubing.
[0035] Alternatively, in S4:
[0036] Raise the tool string until the test sealing rod is inside the first sealing cylinder. The test sealing rod and the first sealing cylinder seal the annulus between the tool string and the central string. Pressurize the annulus between the tool string and the central string to the set pressure using an external pressure testing device. Observe whether there is liquid backflow in the annulus to determine whether the top packer is sealed.
[0037] Alternatively, in S5:
[0038] Raise the tool string until the reverse circulation hole of the filling control tool is sealed in the sealing cylinder of the bottom filling sleeve. Pressurize the annulus between the central string and the tool string to the set pressure using an external pressure testing device, so that all open-hole packers can be set.
[0039] Alternatively, in S6:
[0040] Lift the tool string to position the positioning tool and the second-bottom positioning joint clamp, and mark the second-bottom filling positioning position. Continue to lift the tool string so that the filling sliding sleeve switch tool is above the second-bottom filling sliding sleeve, and at the same time, the circulating sliding sleeve single opening tool is above the bottom circulating sliding sleeve.
[0041] The tool string is lowered to the subbottom filling positioning position. The filling sleeve switch tool controls the opening of the subbottom filling sleeve, and the circulating sleeve single-opening tool controls the opening of the bottom circulating sleeve. Pressure is applied to the drill pipe through external pressure equipment, and the fluid flows from the drill pipe to the subbottom filling sleeve in sequence. Then, it enters the annulus between the central string and the wellbore through the filling channel of the subbottom filling sleeve. Observe whether there is fluid backflow in the annulus to determine whether the bottom open hole packer is sealed.
[0042] Alternatively, in S7:
[0043] Raise the tool string so that the filling sleeve closing tool is above the sub-bottom filling sleeve. Then lower the tool string to the sub-bottom filling positioning position so that the filling sleeve closing tool closes the sub-bottom filling sleeve. Pressurize the drill pipe to the set pressure using an external pressure testing device. The fluid flows from the drill pipe to the filling port of the filling control tool, and then enters the annulus between the sub-bottom filling sleeve and the filling control tool. Observe whether there is fluid backflow in the annulus to determine whether the sub-bottom filling sleeve is closed.
[0044] Alternatively, in S8:
[0045] The tool string is lowered until the positioning tool and the bottom positioning joint are properly positioned, and the bottom filling positioning position is marked. At this time, the filling sliding sleeve switch tool opens the bottom filling sliding sleeve, and the slurry is pumped into the drill pipe through the external pressure equipment. The slurry flows through the drill pipe to the filling port of the filling control tool, then enters the bottom filling sliding sleeve, and enters the annulus between the central string and the wellbore through the filling channel of the bottom filling sliding sleeve. As the filling operation continues, the slurry gradually fills upward until the bottom area of the wellbore is completely filled.
[0046] Alternatively, in S9:
[0047] The tool string is raised, and the washing fluid is pumped into the annulus between the central string and the tool string through the external pressure pumping equipment. The washing fluid enters the internal clamping channel of the filling control tool through the reverse circulation hole, then enters the backwash ball valve through the double-walled interlayer of the filling control tool, and enters the annulus between the central string and the tool string through the discharge channel of the filling control tool. Then it enters the inner cavity through the filling port of the filling control tool, flows upward and returns to the wellhead through the drill pipe, thus initially backwashing the excess slurry in the annulus between the filling control tool and the bottom filling sleeve.
[0048] Continue raising the tool string until the reverse circulation hole of the filling control tool is sealed inside the sealing cylinder of the bottom circulation sleeve. At this point, the filling sleeve closing tool closes the bottom filling sleeve, and the circulation sleeve single-closing tool closes the bottom circulation sleeve. A large amount of well-washing fluid is pumped into the annulus between the central string and the tool string through the external pressure pumping equipment. The large volume of well-washing fluid enters the inner cavity of the filling control tool through the filling port, then flows upward and returns to the wellhead through the drill pipe, thoroughly cleaning the residual sand and slurry in the well.
[0049] Alternatively, in S10:
[0050] Lower the tool string to the bottom filling positioning position, pressurize the drill pipe to the set pressure using external pressure equipment, observe whether there is liquid backflow in the annulus, and determine whether the bottom filling sliding sleeve is closed.
[0051] Optionally, in S11:
[0052] Based on the quantity of the filling production assembly, lift the tool string to position the positioning tool and the third-to-last positioning joint clamp, and mark the positioning position of the third-to-last filling layer. Repeat S6-S10 until the second-to-last layer of the wellbore has completed fracturing filling, reverse circulation well washing, and filling sliding sleeve closure verification. Repeat this process until the top layer of the oil well has completed fracturing filling, reverse circulation well washing, and filling sliding sleeve closure verification. Then, proceed to S12.
[0053] As can be seen from the above technical solution, the integrated open-hole horizontal well fracturing production tubing string and its usage method provided by the present invention have the following advantages:
[0054] This device integrates fracturing and production functions, enabling effective wellbore segmentation, sand control, and selective production. It ensures effective filling, reduces sand production risk, and increases initial well productivity. Furthermore, this design eliminates the need for additional sand control and production tubing, reducing construction costs. Moreover, simple external pressurization and tool string operation allow for easy control of packer setting and the opening and closing of components such as the filling sleeve, simplifying operations and improving efficiency.
[0055] Other features and advantages of the present invention will be set forth in the following description. Attached Figure Description
[0056] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.
[0057] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention;
[0058] Figure 2 This is a schematic diagram of the central tubular column in an embodiment of the present invention;
[0059] Figure 3 This is a schematic diagram of the tool column structure in an embodiment of the present invention;
[0060] Figure 4 This is a structural schematic diagram of an embodiment of the present invention, showing the positional relationship between the reconnection tool and the locking cylinder;
[0061] Figure 5 This is a schematic diagram of the structure of an embodiment of the present invention, showing the fracturing and filling state;
[0062] Figure 6 This is a schematic diagram of the structure of an embodiment of the present invention, showing the initial backwashing state;
[0063] Figure 7 This is a schematic diagram of an embodiment of the present invention, showing the large-volume backwashing state.
[0064] Explanation of reference numerals in the attached figures:
[0065] 1. Top packer; 2. First sealing cylinder; 3. Quick coupling; 4. Filling production assembly; 41. Circulating sleeve; 411. Filling channel; 42. First double-layer screen tube; 43. Production sleeve; 44. Second double-layer screen tube; 45. Second sealing cylinder; 46. Filling sleeve; 47. Positioning clamp; 5. Locking seal assembly; 51. Locking cylinder; 52. Third sealing cylinder; 6. Floating shoe assembly; 61. Liquid-proof lock sealing cylinder; 62. Floating shoe; 7. Open-eye packer; 8. Top setting tool; 9. Test sealing rod; 10. Reconnection rod ; 11. Reconnection tool; 111. Shear pin; 112. Elastic sleeve; 12. Filling control tool; 121. Filling port; 122. Reverse circulation hole; 123. Clamping channel; 124. Double-walled interlayer; 125. Backwash ball valve; 126. Drainage channel; 13. Filling slide sleeve closing tool; 14. Positioning tool; 15. Filling slide sleeve switching tool; 16. Circulation slide sleeve single-closing tool; 17. Circulation slide sleeve single-opening tool; 18. Positioning sealing rod; 19. Shearing slide sleeve; 100. Central tubing; 200. Tool tubing. Detailed Implementation
[0066] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be arbitrarily combined with each other.
[0067] like Figures 1-7The illustration shows an embodiment of the present invention, which discloses an integrated fracturing and production tubing string for open-hole horizontal wells, including a central tubing string 100 and a tool tubing string 200. The central tubing string 100 is run into the wellbore, and the tool tubing string 200 is run into the central tubing string 100 and serves as a service tool for the central tubing string 100. In this embodiment, to more clearly illustrate the direction of fluid flow in the annulus between the central tubing string 100 and the tool tubing string 200, the dimensions of the tool tubing string 200 in the accompanying drawings are appropriately reduced.
[0068] In one embodiment, such as Figure 1 , Figure 2 As shown, the central tubing string 100 includes, from top to bottom, a top packer 1, a first sealing cylinder 2, a quick connector 3, a filling production assembly 4, a locking sealing assembly 5, and a float shoe assembly 6. Multiple filling production assemblies 4 are provided, and adjacent filling production assemblies 4 are connected via an open-hole packer 7. The number of filling production assemblies 4 can be selected according to the actual wellbore depth; this embodiment only shows the state of two filling production assemblies 4.
[0069] In one embodiment, such as Figure 1 , Figure 2 As shown, each filling production assembly 4 includes, from top to bottom, a circulating sleeve 41, a first double-layer screen tube 42, a production sleeve 43, a second double-layer screen tube 44, a second sealing cylinder 45, a filling sleeve 46, and a positioning clamp 47. The quick connector 3 is connected to the uppermost circulating sleeve 41, and the locking sealing assembly 5 is connected to the lowermost positioning clamp 47.
[0070] In one embodiment, such as Figure 1 , Figure 3 As shown, the tool string 200 includes, from top to bottom, a top setting tool 8, a test sealing rod 9, a reconnection rod 10, a reconnection tool 11, a filling control tool 12, a filling slide closing tool 13, a positioning tool 14, a filling slide opening tool 15, a circulating slide single closing tool 16, a circulating slide single opening tool 17, a positioning sealing rod 18, and a shearing slide 19.
[0071] In one embodiment, such as Figure 1 , Figure 2 , Figure 3As shown, the top setting tool 8 is used to control the setting of the top packer 1, and the test sealing rod 9 is used to cooperate with the first sealing cylinder 2 to achieve an annular seal between the central tube 100 and the tool tube 200, so as to facilitate the subsequent sealing verification operation of the top packer 1. The reconnection tool 11 is used to connect with the reconnection rod 10, and the reconnection tool 11 can cooperate with the locking sealing assembly 5 to form a temporary lock. The filling control tool 12 is used to control the opening and closing of its own flow channel. The positioning tool 14 is used to cooperate with the positioning clamp 47 to achieve the positioning of the central tube 100. The shearing sleeve 19 is used to seal the bottom end of the tool tube 200 to facilitate the pressure test operation of the tool tube 200.
[0072] The open-hole horizontal well fracturing and production integrated tubing in this embodiment integrates fracturing and filling functions with production and mining. By setting the open-hole packer 7, the wellbore can be effectively segmented and selectively mined. At the same time, effective segmentation of the wellbore can improve sand control, ensure filling effect, reduce the risk of sand production in the oil well, and increase the initial production capacity after well completion.
[0073] In one embodiment, such as Figure 1 , Figure 2 As shown, the locking and sealing assembly 5 includes a locking cylinder 51 and a third sealing cylinder 52. The third sealing cylinder 52 is connected to the bottom of the locking cylinder 51. The locking cylinder 51 is connected to the lowest positioning clamp 47, and the locking cylinder 51 can cooperate with the reconnection tool 11 to achieve temporary locking.
[0074] In one embodiment, such as Figure 1 , Figure 2 As shown, the float shoe assembly 6 includes a liquid-lock-proof sealing cylinder 61 and a float shoe 62. The liquid-lock-proof sealing cylinder 61 is connected to the bottom of the third sealing cylinder 52, and the float shoe 62 is connected to the bottom of the liquid-lock-proof sealing cylinder 61. The liquid-lock-proof sealing cylinder 61 can effectively prevent liquid from forming a liquid lock inside the sealing cylinder, thereby avoiding equipment failure or operation failure caused by liquid lock, and enabling the tool column 200 to be flushed and lowered simultaneously (see the usage method section for details of the flushing and lowering operation).
[0075] This embodiment also discloses a method for using an integrated fracturing and production tubing string in an open-hole horizontal well, including the following steps:
[0076] S1, connect the center tubing 100 and the tool tubing 200, lower the center tubing 100 into the wellbore, and lower the tool tubing 200 into the center tubing 100.
[0077] The connection of the central tubing string 100 includes: connecting the top packer 1 to the first sealing cylinder 2, and connecting the float shoe 62 to the locking cylinder 51 from bottom to top; selecting the appropriate number of filling production assemblies 4 according to the well depth; connecting two adjacent filling production assemblies 4 through the open hole packer 7; then connecting the locking cylinder 51 to the lowest positioning joint 47; and connecting the quick connector 3 to the uppermost circulating sleeve 41.
[0078] During the connection of the central tubing 100, the circulating sleeve 41, production sleeve 43 and filling sleeve 46 in each filling production assembly 4 are kept in the closed state. At the same time, liquid is injected into each first double-layer screen tube 42 and second double-layer screen tube 44 to ensure internal and external pressure balance. Each filling production assembly 4 is pressure tested to ensure connection sealing.
[0079] The connecting tool string 200 includes: connecting the shearing sleeve 19 to the reconnecting tool 11 from bottom to top, and lowering it into the central string 100 until the reconnecting tool 11 and the locking cylinder 51 form a temporary lock, then connecting the test sealing rod 9 to the reconnecting rod 10, and connecting the test sealing rod 9 to the drill pipe.
[0080] like Figure 4 As shown, the test sealing rod 9 and the reconnection rod 10 are lowered into the central tubing 100 using a drill pipe until the reconnection rod 10 is connected to the reconnection tool 11. Then the tool tubing 200 is lifted up, causing the shearing pin 111 inside the reconnection tool 11 to be cut off, and the elastic sleeve 112 inside the reconnection tool 11 to move down, thereby unlocking the reconnection tool 11.
[0081] After the reconnection tool 11 is unlocked, the tool string 200 is pressure tested using an external pressure testing device. During the pressure testing, the shear pins cut off the bottom port of the tool string 200. After the pressure test, the drill pipe is pressurized to the set pressure using an external pressure testing device, causing the shear pins inside the shear sleeve 19 to cut off, thereby enabling the tool string 200 to connect with the central string 100. Subsequently, the first sealing cylinder 2 is connected to the quick connector 3, and the tool string 200 is lowered.
[0082] S2, During the lowering of tool string 200, pressure is applied to tool string 200 through external pressure equipment to flush out residual mud and sand in the open hole horizontal section using liquid.
[0083] During the lowering of the tool string, external pressure is applied to the drill pipe, causing the fluid to flow from the top setting tool 8 down to the shearing sleeve 19, then through the float shoe 62, and finally back out through the annulus between the central string 100 and the wellbore to flush out residual mud and sand in the open-hole horizontal section.
[0084] S3, control the top packer 1 to set.
[0085] A steel ball of a predetermined size is dropped into the drill pipe, and external pressure is applied to pressurize it until the steel ball shears through the ball seat inside the filling control tool 12, thereby opening the channel within the filling control tool 12. Then, pressure is increased to the predetermined pressure until the top packer 1 is set. Immediately afterwards, pressure is increased to the predetermined pressure, causing the top setting tool 8 to disengage from the top packer 1, thus releasing the lock between the central tubing 100 and the tool tubing 200.
[0086] S4, top packer 1 seal verification.
[0087] Raise the tool string 200 until the test sealing rod 9 is inside the first sealing cylinder 2. At this point, the test sealing rod 9 and the first sealing cylinder 2 seal the annulus between the tool string 200 and the central string 100. Subsequently, pressurize the annulus between the tool string 200 and the central string 100 to the set pressure using an external pressure testing device. Observe whether there is liquid backflow in the annulus. If there is no liquid backflow in the annulus, it proves that the top packer 1 is well set; otherwise, it proves that the top packer 1 has not achieved a complete seal and the top packer 1 setting operation needs to be repeated.
[0088] S5 controls multiple open-hole packers 7 to be set and sealed respectively, so that the multiple open-hole packers 7 divide the wellbore into multiple layers from bottom to top.
[0089] Raise the tool string 200 until the reverse circulation hole 122 of the filling control tool 12 is sealed in the sealing cylinder of the bottom filling sleeve 46. Pressurize the annulus between the central string 100 and the tool string 200 to the set pressure using an external pressure testing device. At this time, all open-hole packers 7 can be set under pressure.
[0090] S6, bottom naked-eye occluder 7-test seal.
[0091] Raise the tool string 200 to position the positioning tool 14 and the second-bottom positioning clamp 47, and mark the second-bottom filling positioning position. Continue to raise the tool string 200 so that the filling slide switch tool 15 is above the second-bottom filling slide 46, and at the same time, the circulating slide single opening tool 17 is above the bottom circulating slide 41.
[0092] The tool string 200 is lowered to the subbottom filling positioning position. During this process, the filling sleeve switch tool 15 controls the opening of the subbottom filling sleeve 46, and the circulating sleeve single-opening tool 17 controls the opening of the bottom circulating sleeve 41. Next, pressure is applied to the drill pipe using external pressure equipment. Fluid flows sequentially from the drill pipe to the subbottom filling sleeve 46, and then enters the annulus between the central tubing 100 and the wellbore through the filling channel 411 of the subbottom filling sleeve 46. The annulus is observed for any fluid return. If no fluid returns, it indicates that the bottom open-hole packer 7 is properly set; otherwise, it indicates that the bottom open-hole packer 7 has not achieved a complete seal, and the open-hole packer 7 setting operation needs to be repeated.
[0093] S7, the second-bottom filling sleeve 46 is closed for verification.
[0094] Raise the tool string 200 so that the filling sleeve closing tool 13 is above the sub-bottom filling sleeve 46. Then lower the tool string 200 to the sub-bottom filling positioning position so that the filling sleeve closing tool 13 closes the sub-bottom filling sleeve 46. Subsequently, pressurize the drill pipe to the set pressure using an external pressurizing device. The fluid flows from the drill pipe to the filling port 121 of the filling control tool 12, and then enters the annulus between the sub-bottom filling sleeve 46 and the filling control tool 12. Observe whether there is fluid backflow in the annulus. If there is no fluid backflow in the annulus, the sub-bottom filling sleeve 46 is closed. Otherwise, it proves that the sub-bottom filling sleeve 46 is not closed. The tool string 200 needs to be raised and lowered again to close the sub-bottom filling sleeve 46.
[0095] S8, fracturing and filling operations are carried out in the bottom area of the wellbore.
[0096] like Figure 5 As shown, the tool string 200 is lowered until the positioning tool 14 and the bottom positioning joint 47 are engaged and positioned, marking the bottom filling positioning position. During this process, the filling sliding sleeve switch tool 15 opens the bottom filling sliding sleeve 46. Subsequently, slurry is pumped into the drill pipe through external pressure equipment. The slurry flows through the drill pipe to the filling port 121 of the filling control tool 12, then enters the bottom filling sliding sleeve 46, and enters the annulus between the central string 100 and the wellbore through the filling channel 411 of the bottom filling sliding sleeve 46. As the filling operation continues, the slurry gradually fills upwards until the bottom area of the wellbore is completely filled, completing the fracturing and filling operation.
[0097] S9, reverse circulation well washing, cleans the residual slurry inside the well.
[0098] like Figure 6As shown, the tool string 200 is raised to ensure that the filling sleeve closing tool 13 is located below the bottom filling sleeve 46. Then, the washing fluid is pumped into the annulus between the central string 100 and the tool string 200 through an external pressure pump. The washing fluid enters the internal clamping channel 123 of the filling control tool 12 through the reverse circulation hole 122, and then enters the backwash ball valve 125 through the double-walled interlayer 124 of the filling control tool 12. Subsequently, the washing fluid enters the annulus between the central string 100 and the tool string 200 through the discharge channel 126 of the filling control tool 12, and then enters its inner cavity through the filling port 121 of the filling control tool 12. It then flows upward and returns to the wellhead through the drill pipe, thus initially backwashing the excess slurry in the annulus between the filling control tool 12 and the bottom filling sleeve 46.
[0099] like Figure 7 As shown, the tool string 200 continues to be raised until the reverse circulation hole 122 of the filling control tool 12 is sealed inside the sealing cylinder of the bottom circulation sleeve 41. During this process, the filling sleeve closing tool 13 closes the bottom filling sleeve 46, and the circulation sleeve single-closing tool 16 closes the bottom circulation sleeve 41. Immediately afterwards, a large amount of well-washing fluid is pumped into the annulus between the central string 100 and the tool string 200 through an external pressure pump. The large volume of well-washing fluid enters the inner cavity of the filling control tool 12 through the filling port 121, then flows upward and returns to the wellhead through the drill pipe, thoroughly cleaning the residual sand and slurry in the well.
[0100] S10, bottom layer filling sleeve 46 closed verification.
[0101] Lower the tool string 200 to the bottom filling positioning position, pressurize the drill pipe to the set pressure using external pressure equipment, and observe whether there is liquid backflow in the annulus. The method for determining whether the bottom filling sliding sleeve 46 is closed is the same as that for the second bottom filling sliding sleeve 46.
[0102] S11, raise the tool string 200 to the corresponding layer of the oil well, and repeat steps S6-S10 until each layer of the oil well has completed fracturing and filling, reverse circulation well washing, and filling of the sliding sleeve 46 for verification.
[0103] Based on the quantity of the filling production assembly 4, raise the tool string 200 to position the positioning tool 14 and the third-to-last positioning joint 47, and mark the positioning position of the third-to-last filling layer. Then, repeat S6-S10 until the second-to-last layer of the wellbore has completed fracturing and filling, reverse circulation well washing, and filling sleeve 46 closure verification. Repeat this process until the top layer of the wellbore has completed fracturing and filling, reverse circulation well washing, and filling sleeve 46 closure verification.
[0104] S12, by controlling the opening of the production sleeve 43 and circulation sleeve 41 of the corresponding layer in the well through the tool string 200, selective production and exploitation of the oil well can be achieved.
[0105] As described above, this tubing string integrates fracturing and production functions, enabling effective wellbore segmentation, sand control, and selective production, ensuring filling effectiveness, reducing sand production risk, and increasing initial well completion productivity. Furthermore, this design eliminates the need for additional sand control and production tubing strings, reducing construction costs. Moreover, the simple operation of external pressurization and raising / lowering the tool tubing string 200 allows for easy setting of the packer and control of the opening and closing of components such as the filling sleeve 46, simplifying the operation process and improving work efficiency.
[0106] Compared with existing technologies, this method can improve formation conductivity and reduce near-wellbore friction in low-to-medium permeability sandstone reservoirs, and effectively prevent sand blockage. For wells with near-wellbore formation blockage, it can perform extrusion unblocking and improve initial production capacity after well completion. Furthermore, it can optimize sand control construction parameters in stages based on the differences in physical properties of horizontal sections, achieving balanced horizontal section stimulation and effectively extending the lifespan of sand control systems.
[0107] Furthermore, the open-hole packer 7 allows for effective segmentation of the horizontal section, enabling selective production. For reservoirs with edge and bottom water, it prevents premature water flooding, which can lead to reduced production capacity and shortened sand control life. This design allows for stratified production of the well. Depending on the water production during later stages of horizontal well production, the production sleeve 43 can be selectively opened or closed using the production sleeve 43 switching tool, achieving segmented water control of the horizontal well's producing layers.
[0108] It should be noted that, unless otherwise stated, the technical or scientific terms used in this invention should have the ordinary meaning as understood by one of ordinary skill in the art.
[0109] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.
[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A method for using an integrated fracturing and production tubing string in an open-hole horizontal well, characterized in that, The open-hole horizontal well fracturing production integrated tubing string includes a central tubing string (100) and a tool tubing string (200). The central tubing string (100) includes a top packer (1), a first sealing cylinder (2), a quick connector (3), a filling production assembly (4), a locking sealing assembly (5), and a float shoe assembly (6) connected sequentially from top to bottom. Multiple filling production assemblies (4) are provided, and two adjacent filling production assemblies (4) are connected by an open-eye packer (7). Each filling production assembly (4) includes, from top to bottom, a circulating sliding sleeve (41), a first double-layer screen tube (42), a production sliding sleeve (43), a second double-layer screen tube (44), a second sealing cylinder (45), a filling sliding sleeve (46), and a positioning clamp (47). The tool string (200) includes, from top to bottom, a top setting tool (8), a test sealing rod (9), a reconnection rod (10), a reconnection tool (11), a filling control tool (12), a filling slide closing tool (13), a positioning tool (14), a filling slide switching tool (15), a circulating slide single closing tool (16), a circulating slide single opening tool (17), a positioning sealing rod (18), and a shearing slide (19). The top setting tool (8) is used to control the setting of the top packer (1), the test sealing rod (9) is used to cooperate with the first sealing cylinder (2) to achieve an annular seal between the central tube (100) and the tool tube (200), the reconnection tool (11) is used to connect with the reconnection rod (10), and the reconnection tool (11) can cooperate with the locking sealing assembly (5) to form a temporary lock, the filling control tool (12) is used to control the opening and closing of its own flow channel, the positioning tool (14) is used to cooperate with the positioning clamp (47) to achieve the positioning of the central tube (100), and the shearing sleeve (19) is used to seal the bottom end of the tool tube (200); The locking and sealing assembly (5) includes a locking cylinder (51) and a third sealing cylinder (52). The third sealing cylinder (52) is connected to the bottom of the locking cylinder (51). The locking cylinder (51) is connected to the lowest positioning clamp (47). The locking cylinder (51) can cooperate with the reconnection tool (11) to achieve temporary locking. The floating shoe assembly (6) includes a liquid-proof sealing cylinder (61) and a floating shoe (62). The liquid-proof sealing cylinder (61) is connected to the bottom of the third sealing cylinder (52), and the floating shoe (62) is connected to the bottom of the liquid-proof sealing cylinder (61). The method for using an integrated fracturing and production tubing string in an open-hole horizontal well includes the following steps: S1, connect the center tubing (100) and the tool tubing (200), lower the center tubing (100) into the wellbore, and lower the tool tubing (200) into the center tubing (100); S2, During the lowering of the tool string (200), pressure is applied to the tool string (200) by external pressure equipment to flush out residual mud and sand in the open hole horizontal section using liquid; S3, control the top packer (1) to set; S4, Top packer (1) seal inspection; S5, control multiple open-hole packers (7) to be set separately so that the multiple open-hole packers (7) divide the wellbore into multiple layers from bottom to top; S6, bottom naked eye occluder (7) seal inspection; S7, the verification of closing the sub-bottom filling sleeve (46) is completed; S8, fracturing and filling operations are carried out in the bottom area of the wellbore; S9, reverse circulation well washing, to clean the residual slurry inside the wellbore; S10, bottom filling sleeve (46) closed verification; S11, lift the tool string (200) to the corresponding layer of the oil well, and repeat steps S6-S10 until each layer of the oil well has completed fracturing and filling, reverse circulation well washing and filling of the sliding sleeve (46) for verification. S12, by controlling the opening of the production sleeve (43) and circulation sleeve (41) of the corresponding layer in the well through the tool string (200), selective production and exploitation of the oil well can be achieved; In S7: Raise the tool string (200) so that the filling sleeve closing tool (13) is above the bottom filling sleeve (46). Then lower the tool string (200) to the bottom filling positioning position so that the filling sleeve closing tool (13) closes the bottom filling sleeve (46). Pressurize the drill pipe to the set pressure through the external pressure equipment. The liquid flows from the drill pipe to the filling port (121) of the filling control tool (12) and then enters the annulus between the bottom filling sleeve (46) and the filling control tool (12). Observe whether there is liquid back out in the annulus to determine whether the bottom filling sleeve (46) is closed. In S8: The tool string (200) is lowered until the positioning tool (14) and the bottom positioning joint (47) are positioned together and the bottom filling positioning position is marked. At this time, the filling sliding sleeve switch tool (15) opens the bottom filling sliding sleeve (46) and pumps the slurry into the drill pipe through the external pressure equipment. The slurry flows through the drill pipe to the filling port (121) of the filling control tool (12) and then enters the bottom filling sliding sleeve (46). It enters the annulus between the central string (100) and the wellbore through the filling channel (411) of the bottom filling sliding sleeve (46). As the filling operation continues, the slurry gradually fills upward until the slurry completely fills the bottom area of the wellbore. In S9: The tool string (200) is lifted, and the washing fluid is pumped into the annulus between the central string (100) and the tool string (200) through the external pressure pumping equipment. The washing fluid enters the internal clamping channel (123) of the filling control tool (12) through the reverse circulation hole (122), then enters the backwash ball valve (125) through the double-walled interlayer (124) of the filling control tool (12), and enters the annulus between the central string (100) and the tool string (200) through the discharge channel (126) of the filling control tool (12). Then it enters the inner cavity through the filling port (121) of the filling control tool (12), flows upward and returns to the wellhead through the drill pipe, thus initially backwashing the excess slurry in the annulus between the filling control tool (12) and the bottom filling sleeve (46). Continue to raise the tool string (200) until the reverse circulation hole (122) of the filling control tool (12) is sealed in the sealing cylinder of the bottom circulation sleeve (41). At this time, the filling sleeve closing tool (13) closes the bottom filling sleeve (46), and the circulation sleeve single-closing tool (16) closes the bottom circulation sleeve (41). A large amount of well-washing fluid is pumped into the annulus between the central string (100) and the tool string (200) through the external pressure pumping equipment. The large volume of well-washing fluid enters its inner cavity through the filling port (121) of the filling control tool (12), then flows upward and returns to the wellhead through the drill pipe, thoroughly cleaning the residual sand and slurry in the well.
2. The method of use according to claim 1, characterized in that, In S1: The connection of the central tubing string (100) includes: connecting the top packer (1) to the first sealing cylinder (2), and connecting the float shoe (62) to the locking cylinder (51) from bottom to top; selecting the appropriate number of filling production assemblies (4) according to the well depth; connecting two adjacent filling production assemblies (4) through the open hole packer (7); connecting the locking cylinder (51) to the lowest positioning joint (47); and connecting the quick connector (3) to the uppermost circulating sleeve (41). Ensure that the circulating sleeve (41), production sleeve (43) and filling sleeve (46) in each filling production assembly (4) are in the closed state. Fill each first double-layer screen tube (42) and second double-layer screen tube (44) with liquid to ensure internal and external pressure balance. Perform pressure test on each filling production assembly (4) to ensure connection sealing. The connecting tool string (200) includes: connecting the shearing sleeve (19) to the reconnecting tool (11) from bottom to top, and lowering it into the central string (100) until the reconnecting tool (11) and the locking cylinder (51) form a temporary lock. Then, the test sealing rod (9) is connected to the reconnecting rod (10), and the test sealing rod (9) is connected to the drill pipe. The drill pipe carries the test sealing rod (9) and the reconnecting rod (10) into the central string (100) until the reconnecting rod (10) and the reconnecting tool (11) are connected. Then, the tool string (200) is lifted up to unlock the reconnecting tool (11) and the locking cylinder (51). After the reconnection tool (11) is unlocked, the tool string (200) is pressure tested, and then the drill pipe is pressurized to the set pressure by an external pressure testing device to cut the shear pin in the shear sleeve (19) so as to realize the connection between the tool string (200) and the central string (100). Then, the first sealing cylinder (2) is connected to the quick connector (3), and the tool string (200) is lowered.
3. The method of use according to claim 1, characterized in that, In S2: During the lowering of the tool string, external pressure equipment pressurizes the drill pipe, causing the fluid to flow from the top setting tool (8) to the shearing sleeve (19), then through the float shoe (62), and back out through the annulus between the central string (100) and the wellbore to flush out residual mud and sand in the open-hole horizontal section.
4. The method of use according to claim 1, characterized in that, In S3: A steel ball of a set size is placed and the drill pipe is pressurized by an external pressurizing device until the steel ball shears and fills the ball seat in the filling control tool (12) to open the channel in the filling control tool (12). Pressurization continues until the top packer (1) is set. Then, pressurization continues until the top setting tool (8) is released from the top packer (1) to release the lock between the central string (100) and the tool string (200).
5. The method of use according to claim 1, characterized in that, In S4: Raise the tool string (200) until the test sealing rod (9) is inside the first sealing cylinder (2). The test sealing rod (9) and the first sealing cylinder (2) seal the annulus between the tool string (200) and the central string (100). Pressurize the annulus between the tool string (200) and the central string (100) to the set pressure using an external pressure testing device. Observe whether there is liquid backflow in the annulus to determine whether the top packer (1) is sealed.
6. The method of use according to claim 1, characterized in that, In S5: Raise the tool string (200) until the anti-circulation hole (122) of the filling control tool (12) is sealed in the sealing cylinder of the bottom filling sleeve (46). Pressurize the annulus between the central string (100) and the tool string (200) to the set pressure through the external pressure equipment so that all open-eye packers (7) can be set.
7. The method of use according to claim 1, characterized in that, In S6: Raise the tool string (200) to position the positioning tool (14) and the second bottom positioning clamp (47) together, and mark the second bottom filling positioning position. Continue to raise the tool string (200) so that the filling slide switch tool (15) is above the second bottom filling slide (46), and at the same time, the circulating slide single opening tool (17) is above the bottom circulating slide (41). The tool string (200) is lowered to the subbottom filling positioning position. The filling sleeve switch tool (15) controls the opening of the subbottom filling sleeve (46). The circulating sleeve single opening tool (17) controls the opening of the bottom circulating sleeve (41). The external pressure equipment pressurizes the drill pipe, and the liquid flows from the drill pipe to the subbottom filling sleeve (46) in sequence. Then, it enters the annulus between the central string (100) and the wellbore through the filling channel (411) of the subbottom filling sleeve (46). Observe whether there is liquid backflow in the annulus to determine whether the bottom open hole packer (7) is sealed.
8. The method of use according to claim 1, characterized in that, In S10: Lower the tool string (200) to the bottom filling positioning position, pressurize the drill pipe to the set pressure through the external pressure equipment, observe whether there is liquid back out in the annulus, and determine whether the bottom filling sliding sleeve (46) is closed.
9. The method of use according to claim 1, characterized in that, In S11: Based on the quantity of the filling production assembly (4), lift the tool string (200) to position the positioning tool (14) and the third-to-last positioning joint (47) and mark the third-to-last filling positioning position. Repeat S6-S10 until the second-to-last area of the wellbore has completed fracturing filling, reverse circulation well washing, and filling sleeve (46) closure verification. Repeat this process until the top area of the oil well has completed fracturing filling, reverse circulation well washing, and filling sleeve (46) closure verification. Then, proceed to S12.