A method for stabilizing oil and controlling water in a low water cut stage of an oil field

Abstract

The present application relates to the technical field of oilfield oil stabilizing and water controlling, and particularly relates to an oilfield low water content period oil stabilizing and water controlling method, which comprises a plurality of inner connecting pipe sections and a plurality of outer connecting pipe sections, the outer connecting pipe section is in contact with the stratum through the outer peripheral side wall, the adjacent two inner connecting pipe sections are detachably connected through a water control valve, and the outer peripheral side wall middle section of each inner connecting pipe section is sleeved with a positioning inner blocking ring, the outer connecting pipe section is slidably sleeved in the positioning inner blocking ring, and the outer peripheral side wall middle section of each outer connecting pipe section is sleeved with a positioning outer blocking frame. The present application divides the length with small water content change or similar water content into a section by regulating the section length, so that the water content change of the oil-water mixture flowing to the section is small after mixing, and then the viscosity change of the oil-water mixture flowing to the water control valve is small, the water control valve needs to be continuously adjusted to be suitable for the continuously changing oil-water mixture, and the opening adjustment intensity of the water control valve is reduced.

Description

Technical Field

[0001] This invention relates to the field of oilfield stabilization and water control technology, specifically to a method for stabilizing oil and controlling water during the low water-cut period of an oilfield. Background Technology

[0002] With the development of petroleum exploration and development technology, the use of horizontal well technology to develop oil and gas fields has become an effective technical means to improve oilfield recovery rate and single-well production, extract residual oil, and reduce the cost per ton of oil. Horizontal wells increase the contact area between the wellbore and the reservoir. Compared with conventional vertical wells, they can better develop thin oil layers or oil reservoirs with high vertical permeability. The production capacity of horizontal wells depends on the reservoir conditions, the length of the horizontal well section, and the completion method. As oilfields are continuously developed, the water cut continues to rise. When the water cut of an oilfield is greater than 60%, it enters the high water cut period. When it is below 60%, it is generally in the low water cut period. However, even in the low water cut period, it is still necessary to stabilize oil and control water to extract and refine the oil-water mixture with low water cut as much as possible.

[0003] Existing oilfield water stabilization and control technologies during low water cut periods typically employ multiple external connecting pipe sections to divide the oil-bearing formation into different segments. This allows the oil-water mixture in each segment to flow to a corresponding water control valve. The valve automatically adjusts its opening based on the viscosity of the oil-water mixture, enabling continuous real-time regulation of the oil-water mixture flow rate according to changes in reservoir water cut in different segments. This segmented control of the oil-water mixture in different formation segments facilitates the entry of low-water-cut oil-water mixtures into the internal connecting pipe sections, thus achieving water stabilization and control. However, in this structure, the positions of the multiple external connecting pipe sections are generally fixed and cannot be easily determined. The adjustment ensures that the length of different sections of the formation defined by the external connecting pipe section is constant. However, due to the varying water content of the oil-water mixture at different lengths within this section, the water content of the oil-water mixture flowing to the water control valve varies significantly. Consequently, the viscosity of the oil-water mixture flowing to the internal connecting pipe section varies considerably after mixing. This necessitates continuous adjustment of the water control valve's opening based on the viscosity, increasing the adjustment intensity of the water control valve. Over long-term use, the high workload of the water control valve may lead to opening errors, affecting the oil stabilization and water control effect, and potentially reducing the service life of the water control valve.

[0004] Therefore, it is necessary to invent a method for stabilizing oil production and controlling water during the low water-cut period of oilfields to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for stabilizing oil production and controlling water during the low water cut period in oilfields. This method solves the problem that in existing technologies, the positions of multiple external connecting pipe sections are generally fixed and cannot be adjusted. This results in a fixed length for different formation sections defined by the external connecting pipe sections. However, because the water content of the oil-water mixture varies at different lengths within these sections, the water content of the mixture flowing towards the water control valve varies significantly. Consequently, the viscosity of the mixture flowing towards the internal connecting pipe sections varies considerably. This necessitates continuous adjustment of the water control valve's opening based on viscosity, increasing the adjustment intensity of the valve. Over long-term use, the high workload of the water control valve may lead to opening errors, affecting the oil stabilization and water control effect and potentially reducing the service life of the water control valve.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for stabilizing oil production and controlling water during the low water cut period in an oilfield includes multiple internal connecting pipe sections and multiple external connecting pipe sections. The outer peripheral sidewall of the external connecting pipe section is in contact with the formation. Adjacent internal connecting pipe sections are detachably connected by a water control valve. Each internal connecting pipe section has a positioning inner barrier ring fitted in the middle section of its outer peripheral sidewall. The external connecting pipe section is slidably fitted on the positioning inner barrier ring. Each external connecting pipe section has a positioning outer barrier frame fitted in the middle section of its outer peripheral sidewall. Multiple self-extending telescopic components are connected between the sidewalls of two adjacent positioning outer barrier frames that are close to each other. A sleeve is detachably connected to the multiple telescopic components. The two ends of the sleeve are slidably fitted on two adjacent external connecting pipe sections. The sleeve has multiple perforations for the inflow of oil-water mixture.

[0008] The telescopic assembly automatically extends and retracts, changing the lateral distance between two adjacent positioning outer barrier frames, thereby causing two adjacent outer connecting pipe sections to move closer or further apart. In turn, the two adjacent positioning outer barrier frames isolate the formation into different sections. The oil-water mixture in these sections can flow in through the perforations on the corresponding casing, and the viscosity of the oil-water mixture in different sections can be controlled segmentally by adjusting the opening of the water control valve.

[0009] As a preferred embodiment of the present invention, the sleeve is connected to external sealing flanges at both ends, and a sealing ring is embedded in the inner circumferential sidewall of the external sealing flange. The sealing ring is laterally slidably sleeved on the corresponding external connecting pipe section.

[0010] As a preferred embodiment of the present invention, the telescopic assembly includes a horizontal cylinder and a plurality of telescopic rods that slide laterally through both ends of the horizontal cylinder. Fixed blocks are connected to the matching positions on both sides of the outer peripheral sidewall of the sleeve. The telescopic rods slide laterally through the fixed blocks. The end of the telescopic rod away from the horizontal cylinder is detachably connected to the corresponding positioning outer barrier.

[0011] As a preferred embodiment of the present invention, the right end of the rightmost inner connecting pipe section is detachably connected to an inner guide shoe, and the right end of the rightmost outer connecting pipe section is detachably connected to an outer guide shoe, wherein the inner guide shoe is inserted inside the outer guide shoe.

[0012] As a preferred embodiment of the present invention, both ends of the water control valve are detachably connected to the inner connecting pipe sections on both sides via inner sealing flanges.

[0013] As a preferred embodiment of the present invention, the left end of the leftmost inner connecting pipe section is detachably connected to an inner completion straight pipe fitting via an inner bend connecting pipe fitting, and the left end of the leftmost outer connecting pipe section is detachably connected to an outer completion straight pipe fitting via an outer bend connecting pipe fitting. A suspension inner barrier ring is provided between the inner and outer completion straight pipe fittings, and a suspension outer barrier frame is detachably fitted on the outer peripheral sidewall of the outer completion straight pipe fitting.

[0014] In a preferred embodiment of the present invention, the inner guide shoe and a plurality of spaced-apart inner connecting pipe sections together with the water control valve form an inner pipe fitting, and the outer guide shoe and a plurality of spaced-apart slidingly connected outer connecting pipe sections together with the sleeve form an outer pipe fitting.

[0015] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0016] This invention uses multiple water control valves to detachably connect the internal connecting pipe sections, forming the main components of a horizontal well. During deep formation oilfield extraction, the telescopic components autonomously extend and retract, changing the lateral distance between two adjacent positioning outer barrier frames. During this process, the two adjacent outer connecting pipe sections slide closer or further apart within the same casing, causing them to slide along the corresponding positioning inner barrier rings. This, in turn, divides the formation into different sections using the positioning outer barrier frames. Two adjacent positioning outer barrier frames define one section, which is sealed off by two internal connecting pipe sections on each side, two external connecting pipe sections, and two positioning inner barrier rings in between. This ensures that the oil-water mixture flowing in through the perforations on the casing of that section can only be controlled by adjusting the opening of the water control valves within that section, thereby controlling the flow. Each section's water control valve performs segmented control of the oil-water mixture in different sections. The length of each section can be adjusted via a telescopic component. During actual extraction, by adjusting the section length, sections with small or similar water content variations can be grouped together. This results in a smaller change in the water content of the oil-water mixture flowing into that section after mixing, and consequently, a smaller viscosity change when the mixture flows to the water control valve. This avoids the need for constant valve opening adjustments to accommodate the constantly changing oil-water mixture, reducing the intensity of valve opening adjustments. Over long-term use, this prevents opening errors caused by high workload on the water control valve, thus avoiding impacts on oil and water stability. By extending the service life of the water control valve, oil and water stability control is achieved during the oilfield extraction phase. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 This is a schematic diagram of the planar top view structure of the present invention;

[0019] Figure 3 For the present invention Figure 2 Schematic diagram of the cross-sectional structure at point AA.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1. Inner fittings; 2. Outer fittings; 3. Inner connecting pipe section; 4. Water control valve; 5. Outer connecting pipe section; 6. Positioning inner barrier ring; 7. Positioning outer barrier frame; 8. Casing; 9. Perforation; 10. Outer sealing flange; 11. Sealing ring; 12. Fixing block; 13. Horizontal cylinder; 14. Telescopic rod; 15. Inner sealing flange; 16. Inner guide shoe; 17. Outer guide shoe; 18. Inner bending connecting pipe fitting; 19. Outer bending connecting pipe fitting; 20. Inner completion straight pipe fitting; 21. Suspended inner barrier ring; 22. Suspended outer barrier frame; 23. Outer completion straight pipe fitting. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0023] This invention provides, for example Figure 1-3 The method for stabilizing oil and controlling water during the low water cut period in an oilfield includes multiple internal connecting pipe sections 3 and multiple external connecting pipe sections 5. The outer peripheral sidewall of the external connecting pipe section 5 is in contact with the formation. Adjacent internal connecting pipe sections 3 are detachably connected by a water control valve 4. Each internal connecting pipe section 3 has a positioning inner barrier ring 6 fitted in the middle section of its outer peripheral sidewall. The external connecting pipe section 5 is slidably fitted on the positioning inner barrier ring 6. Each external connecting pipe section 5 has a positioning outer barrier frame 7 fitted in the middle section of its outer peripheral sidewall. Multiple self-extending telescopic components are connected between the sidewalls of two adjacent positioning outer barrier frames 7 that are close to each other. The multiple telescopic components are detachably connected to a sleeve 8. The two ends of the sleeve 8 are slidably fitted on two adjacent external connecting pipe sections 5, and the sleeve 8 has multiple perforations 9 for the inflow of oil-water mixture.

[0024] The telescopic components automatically extend and retract, changing the lateral distance between two adjacent positioning outer barrier frames 7, thereby causing two adjacent outer connecting pipe sections 5 to move closer or further apart. In turn, the two adjacent positioning outer barrier frames 7 isolate the formation into different sections. The oil-water mixture in this section can flow in through the perforation 9 on the corresponding casing 8, and the viscosity of the oil-water mixture in different sections can be controlled segmentally by adjusting the opening of the water control valve 4.

[0025] The sleeve 8 is connected to two external sealing flanges 10. A sealing ring 11 is embedded in the inner circumferential side wall of the external sealing flange 10. The sealing ring 11 is laterally slidably fitted onto the corresponding external connecting pipe section 5. The sealing ring 11 can improve the sealing degree between the external sealing flange 10 and the external connecting pipe section 5 during the lateral sliding process, and prevent oil-water mixture from seeping out from there.

[0026] The telescopic assembly includes a horizontal cylinder 13 and multiple telescopic rods 14 that slide laterally through both ends of the horizontal cylinder 13. Fixing blocks 12 are connected to the matching positions on both sides of the outer peripheral sidewall of the sleeve 8. The telescopic rods 14 slide laterally through the fixing blocks 12. The end of the telescopic rod 14 away from the horizontal cylinder 13 is detachably connected to the corresponding positioning outer barrier 7. The fixing blocks 12 can fix the positional relationship between the horizontal cylinder 13 and the sleeve 8, and the telescopic direction of the telescopic rods 14 can be limited by the limiting of the fixing blocks 12.

[0027] according to Figure 1As shown, the right end of the rightmost inner connecting pipe section 3 is detachably connected to an inner guide shoe 16, and the right end of the rightmost outer connecting pipe section 5 is detachably connected to an outer guide shoe 17. The inner guide shoe 16 is inserted inside the outer guide shoe 17. The inner guide shoe 16 and the outer guide shoe 17 facilitate the horizontal advancement of the entire mining operation while preventing end leakage.

[0028] Both ends of the water control valve 4 are detachably connected to the inner connecting pipe sections 3 on both sides via inner sealing flanges 15. The inner sealing flanges 15 can improve the sealing performance of the connection between the water control valve 4 and the inner connecting pipe sections 3 on both sides.

[0029] according to Figure 1 As shown, the left end of the leftmost inner connecting pipe section 3 is detachably connected to the inner completion straight pipe section 20 via the inner bend connecting pipe fitting 18. The left end of the leftmost outer connecting pipe section 5 is detachably connected to the outer completion straight pipe section 23 via the outer bend connecting pipe fitting 19. A suspension inner barrier ring 21 is provided between the inner completion straight pipe section 20 and the outer completion straight pipe section 23. A suspension outer barrier frame 22 is detachably fitted on the outer peripheral side wall of the outer completion straight pipe section 23. The inner completion straight pipe section 20 and the outer completion straight pipe section 23 can extend to the ground, so that the inner connecting pipe section 3 and the outer connecting pipe section 5 can communicate with the ground.

[0030] The inner guide shoe 16 and multiple intermittently connected inner connecting pipe sections 3 and water control valve 4 together form the inner pipe fitting 1, and the outer guide shoe 17 and multiple intermittently slidingly connected outer connecting pipe sections 5 and sleeve 8 together form the outer pipe fitting 2.

[0031] This invention uses multiple water control valves 4 to detachably connect the internal connecting pipe sections 3, thus forming the main components of a horizontal well. During deep formation oilfield extraction, the telescopic components autonomously extend and retract, changing the lateral distance between two adjacent positioning outer barrier frames 7. During this process, two adjacent outer connecting pipe sections 5 slide closer or further apart within the same casing 8, causing them to slide along the corresponding positioning inner barrier rings 6. This, in turn, divides the formation into different sections using the positioning outer barrier frames 7. Two adjacent positioning outer barrier frames 7 define one section, which is sealed off by the two internal connecting pipe sections 3 on either side, the two external connecting pipe sections 5, and the two positioning inner barrier rings 6 in between. This ensures that the oil-water mixture flowing into the casing 8 through the perforation 9 in that section can only be adjusted for opening via the water control valves 4 in that section. Furthermore, the water control valves 4 in each section are used to achieve segmented control of the oil-water mixture in different sections. The length of each section can be adjusted by the telescopic component. In actual mining, by adjusting the section length, sections with small or similar water content changes can be divided into sections, resulting in smaller changes in water content after mixing of the oil-water mixture flowing into that section. This also reduces the viscosity change of the oil-water mixture flowing into the water control valves 4, avoiding the need for the water control valves 4 to constantly adjust their opening to handle the constantly changing oil-water mixture. This reduces the intensity of opening adjustment for the water control valves 4 and prevents opening errors due to high workload during long-term use, thus avoiding affecting the oil stabilization and water control effect. Under the premise of improving the service life of the water control valves 4, the oil stabilization and water control in the oilfield mining stage is achieved.

[0032] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for stabilizing oil production and controlling water during the low water-cut period in oilfields, characterized in that: It includes multiple internal connecting pipe sections (3) and multiple external connecting pipe sections (5). The outer peripheral sidewall of the external connecting pipe section (5) is in contact with the formation. The two adjacent internal connecting pipe sections (3) are detachably connected by a water control valve (4). The middle section of the outer peripheral sidewall of each internal connecting pipe section (3) is fitted with a positioning inner barrier ring (6). The external connecting pipe section (5) is slidably fitted on the positioning inner barrier ring (6). The middle section of the outer peripheral sidewall of each external connecting pipe section (5) is fitted with a positioning outer barrier frame (7). Multiple self-extending telescopic components are connected between the sidewalls of two adjacent positioning outer barrier frames (7). The multiple telescopic components are detachably connected to a sleeve (8). The two ends of the sleeve (8) are slidably fitted on two adjacent external connecting pipe sections (5). The sleeve (8) has multiple perforations (9) for the inflow of oil-water mixture. The telescopic assembly automatically extends and retracts, changing the lateral distance between two adjacent positioning outer barrier frames (7), thereby causing two adjacent outer connecting pipe sections (5) to move closer or further apart. In turn, the two adjacent positioning outer barrier frames (7) isolate the formation into different sections. The oil-water mixture in this section can flow in through the perforation (9) on the corresponding casing (8), and the viscosity of the oil-water mixture in different sections can be segmented by adjusting the opening of the water control valve (4). By adjusting the length of the section, the length with small or similar water content changes can be divided into a section, so that the water content of the oil-water mixture flowing into the section changes less after mixing, and the viscosity of the oil-water mixture flowing into the water control valve (4) changes less, thus avoiding the need for the water control valve (4) to constantly adjust its opening to deal with the constantly changing oil-water mixture, and reducing the intensity of the opening adjustment of the water control valve (4).

2. The method for stabilizing oil production and controlling water during the low water-cut period in oilfields according to claim 1, characterized in that: The sleeve (8) is connected to an outer sealing flange (10) at both ends. A sealing ring (11) is embedded in the inner circumferential side wall of the outer sealing flange (10). The sealing ring (11) is laterally slidably sleeved on the corresponding outer connecting pipe section (5).

3. The method for stabilizing oil production and controlling water during the low water-cut period in oilfields according to claim 1, characterized in that: The telescopic assembly includes a horizontal cylinder (13) and multiple telescopic rods (14) that slide laterally through both ends of the horizontal cylinder (13). The sleeve (8) has a fixed block (12) connected to both sides of the outer peripheral sidewall. The telescopic rod (14) slides laterally through the fixed block (12). The end of the telescopic rod (14) away from the horizontal cylinder (13) is detachably connected to the corresponding positioning outer barrier (7).

4. The method for stabilizing oil production and controlling water during the low water-cut period in oilfields according to claim 1, characterized in that: The right end of the rightmost inner connecting pipe section (3) is detachably connected to an inner guide shoe (16), and the right end of the rightmost outer connecting pipe section (5) is detachably connected to an outer guide shoe (17), and the inner guide shoe (16) is inserted inside the outer guide shoe (17).

5. The method for stabilizing oil production and controlling water during the low water-cut period in an oilfield according to claim 1, characterized in that: The water control valve (4) is detachably connected to the inner connecting pipe sections (3) on both sides via inner sealing flanges (15).

6. The method for stabilizing oil production and controlling water during the low water-cut period in an oilfield according to claim 1, characterized in that: The left end of the leftmost inner connecting pipe section (3) is detachably connected to an inner well completion straight pipe section (20) via an inner bend connecting pipe section (18). The left end of the leftmost outer connecting pipe section (5) is detachably connected to an outer well completion straight pipe section (23) via an outer bend connecting pipe section (19). A suspension inner barrier ring (21) is provided between the inner well completion straight pipe section (20) and the outer well completion straight pipe section (23). A suspension outer barrier frame (22) is detachably fitted on the outer peripheral side wall of the outer well completion straight pipe section (23).

7. The method for stabilizing oil production and controlling water during the low water-cut period of an oilfield according to claim 4, characterized in that: The inner guide shoe (16) and the multiple inner connecting pipe sections (3) connected at intervals together with the water control valve (4) form an inner pipe (1), and the outer guide shoe (17) and the multiple outer connecting pipe sections (5) connected at intervals together with the sleeve (8) form an outer pipe (2).

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