Switchable infinite fracturing sliding sleeve for coiled tubing

Abstract

The utility model relates to the field of oil and gas wells, and discloses a continuous oil pipe switchable infinite fracturing sliding sleeve which comprises an outer cylinder, a lower connector and an inner sliding sleeve arranged in the outer cylinder, the lower connector is fixedly connected with the outer cylinder, a plurality of sand blasting holes are formed in the outer cylinder in the circumferential direction, and the sand blasting holes can flow through after the inner sliding sleeve slides. A limiting ring is arranged on the lower connector in the sliding direction of the inner sliding sleeve, a gap is formed between the limiting ring and the initial position of the inner sliding sleeve, and the inner sliding sleeve abuts against the limiting ring after sliding to the limiting position. The fracturing sliding sleeve is convenient to position and can be opened and closed.

Description

TECHNICAL FIELD

[0001] The utility model relates to oil and gas well field, concretely relates to continuous tubing switchable unlimited level fracturing sliding sleeve. BACKGROUND

[0002] Casing sliding sleeve fracturing process technology is a kind of technology using high-pressure pump to inject fracturing liquid into well wall to enhance formation permeability and improve oil well productivity, is widely applied in oilfield exploration and development, has simple operation, obvious effect and other advantages;In addition, horizontal well multistage sliding sleeve staged fracturing technology is an important means for unconventional oil and gas resource exploitation, has simple structure, construction reliability and other characteristics.This fracturing technology is widely applied to the fracturing stimulation of shale gas, low-permeability pay zone and thin oil layer.In the later stage of oil and gas well exploitation, when encountering pay zone water production, selective exploitation and re-fracturing, sliding sleeve switch pipe column needs to be lowered to carry out sliding sleeve switch operation, and the sliding sleeve is selectively closed to achieve the purpose of plugging bottom water, layered plugging test and production. SUMMARY

[0003] The utility model intends to provide continuous tubing switchable unlimited level fracturing sliding sleeve to provide a kind of fracturing sliding sleeve that is convenient to position and switch.

[0004] To achieve the above purpose, the utility model adopts the following technical scheme: continuous tubing switchable unlimited level fracturing sliding sleeve, including outer tube, lower joint and the inner sliding sleeve being arranged in outer tube, lower joint is fixedly connected with outer tube, outer tube is opened with multiple sand blasting holes in circumference, and inner sliding sleeve can make sand blasting hole flow after sliding, lower joint is provided with limit ring along the sliding direction of inner sliding sleeve, there is gap between limit ring and initial position of inner sliding sleeve, and inner sliding sleeve is abutted with limit ring after sliding to limit position.

[0005] The beneficial effects of the present scheme are as follows:

[0006] The fracturing sliding sleeve in the technical solution is placed in the formation in alignment with the oil and gas layer, a certain number of fracturing sliding sleeves are connected according to the corresponding positions (interval distances) according to the number requirement of the oil and gas layer, at this time, the inner sliding sleeve blocks the sandblasting hole, so the fracturing sliding sleeve is in a closed state, the inner diameters of the plurality of fracturing sliding sleeves remain consistent, and the fracturing sliding sleeve is lowered into position and then cementing is performed, when the fracturing sliding sleeve needs to be opened, the switching sliding sleeve tool is brought in through the coiled tubing tool and is lowered into a predetermined position (in general, it is opened or closed step by step from the deepest position), the switching sliding sleeve tool can be repeatedly set and sealed with the inner sliding sleeve, drives the inner sliding sleeve to slide along the outer cylinder, after being lowered into the predetermined position, the tool string is slowly lifted and lowered, the inner diameter of the normal casing is the same, there is no tonnage load change when the switching sliding sleeve tool is lowered, when the tool string is lowered, the tool string will be popped open between the inner sliding sleeve and the limiting ring, whether the positioning unit is in place can be judged according to the lifting and lowering force through the sensing of the popping open and the tonnage load change caused by a certain hanging force when the tool string is lifted and lowered, whether the convex ring part has been clamped into the set position can be judged, after the position is judged, the tool string is lifted a certain distance through the coiled tubing, and the direction of the packer track is changed through the friction force, the setting is completed by continuing to lower, the switching sliding sleeve tool slides downward together with the inner sliding sleeve, and the opening work of the fracturing sliding sleeve is completed, after the sandblasting hole is opened, the ground high-pressure pump enters liquid and proppant from the annulus through the sandblasting hole into the formation, and fracturing is completed, after the fracturing sliding sleeve is opened and the fracturing of the current section is completed, the tool string is lifted, the setting is released, the inner sliding sleeve slides to enable the sandblasting hole to be quickly opened and closed, the timing and range of fracturing can be accurately controlled by the operating personnel, the accuracy of fracturing operation is improved, and the sandblasting hole can be closed by pulling the tool string in the reverse direction.

[0007] By arranging the limiting ring, on the one hand, the tool string can be matched with the inner sliding sleeve at an accurate position during setting, and on the other hand, the sliding distance of the inner sliding sleeve can be limited, so that the inner sliding sleeve can be pushed back if it is desired to close the fracturing sliding sleeve in the subsequent operation, the subsequent downhole operation (such as secondary fracturing or production testing) is facilitated, the utilization efficiency of the downhole tool is improved, and the controllability of the fracturing operation is ensured.

[0008] Preferably, as an improvement, alloy rings are arranged at the sandblasting holes.

[0009] The alloy ring is usually made of high-hardness and high-wear-resistant material, can effectively resist the cutting and wear of high-speed flowing fracturing fluid and sand particles, prolongs the service life of the sandblasting hole, and greatly reduces the wear degree of the hole wall caused by the erosion of liquid and sand particles, avoids deformation or expansion of the sandblasting hole, and ensures long-term stable use.

[0010] Preferably, as an improvement, a lock ring is further arranged on the outer surface of the inner and outer sleeves.

[0011] The beneficial effect is that: by setting the locking ring, a certain pushing force is needed to push open or close the sandblasting hole, when closing the sandblasting hole, the tool string is stuck in the positioning groove, and by lifting a certain force, the locking ring can be opened to achieve closing, which prevents ordinary friction from driving the inner sleeve to close the sandblasting hole.

[0012] Preferably, as an improvement, the inner sleeve and the outer cylinder are circumferentially arrayed with connecting holes, and fixed pins for connecting the inner sleeve and the outer cylinder are embedded in the connecting holes.

[0013] The beneficial effect is that: the shear force of the fixed pin is accurately calculated, which can withstand the impact force of the sleeve in normal operation, and can be sheared off when the set shear force is reached, realizing the sliding of the inner sleeve; under the action of external force, the inner sleeve slides smoothly after the pin is sheared off, avoiding the phenomenon of jamming during sliding, improving the reliability of the sleeve opening, and the fixed pin ensures that the inner sleeve remains stable when subjected to unexpected external force, preventing the sleeve from opening or closing in the non-scheduled position, and avoiding downhole operation accidents.

[0014] Preferably, as an improvement, the number of sandblasting holes is 18.

[0015] The beneficial effect is that: the 18 sandblasting holes are evenly distributed circumferentially, ensuring that the fracturing fluid and proppant can be uniformly sprayed to the formation, improving the fracturing effect, reducing the risk of uneven damage to the formation caused by local high pressure, and the multi-hole design allows fluid to act on a larger area of the formation at the same time, improving the coverage of the fracturing operation, thereby optimizing the oil and gas production efficiency.

[0016] Preferably, as an improvement, it further comprises an upper joint fixedly connected with the outer cylinder. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an embodiment of the present utility model;

[0018] Figure 2 It is a sandblasting hole closing sectional view of an embodiment of the present utility model;

[0019] Figure 3 It is a sandblasting hole opening sectional view of an embodiment of the present utility model. DETAILED DESCRIPTION

[0020] The following will be further described in detail through specific embodiments:

[0021] The reference signs in the drawings of the specification include: outer cylinder 1, inner sleeve 2, sandblasting hole 3, limiting ring 4, alloy ring 5, locking ring 6, connecting hole 7, upper joint 8, lower joint 9.

[0022] EMBODIMENT

[0023] The embodiment is substantially as Figures 1-3 As shown in Figure 1 and Figure 2 The coiled tubing switchable infinite-stage fracturing sliding sleeve includes an outer cylinder 1, a lower joint 9 fixedly connected with the outer cylinder 1, and an inner sliding sleeve 2 arranged in the outer cylinder 1. The outer cylinder 1 is provided with a plurality of sand blasting holes 3 in the circumferential direction. In the embodiment, the number of the sand blasting holes 3 is 18. The sand blasting holes 3 are uniformly distributed in the circumferential direction and can be flowed through after the sliding of the inner sliding sleeve 2, ensuring that the fracturing fluid and proppant can be uniformly sprayed to the formation to improve the fracturing effect. The lower joint 9 is provided with a limiting ring 4 along the sliding direction of the inner sliding sleeve 2, and there is a gap between the limiting ring 4 and the initial position of the inner sliding sleeve 2. The inner sliding sleeve 2 abuts against the limiting ring 4 after sliding to the limit position. An alloy ring 5 is embedded at each of the sand blasting holes 3. The alloy ring 5 is usually made of high-hardness and high-wear-resistant material, can effectively resist the cutting and wear of the high-speed flowing fracturing fluid and sand particles, prolongs the service life of the sand blasting hole 3, and serves as a protective layer of the sand blasting hole 3, greatly reducing the wear degree of the hole wall caused by the erosion of the liquid and sand particles, avoiding the deformation or expansion of the sand blasting hole 3, and ensuring long-term stable use. A lock ring 6 is further sleeved on the outer surface of the inner and outer sleeves. By arranging the lock ring 6, a certain pushing force is required to push the sand blasting hole 3 open or closed. When the sand blasting hole 3 is closed, the tool string is clamped in the positioning groove, and a certain force is applied to pop open the lock ring 6, realizing the closing and preventing ordinary friction from driving the inner sliding sleeve to close or open the sand blasting hole. The inner sliding sleeve 2 and the outer cylinder 1 are provided with connecting holes 7 in the circumferential direction. A fixed pin for connecting the inner sliding sleeve 2 and the outer cylinder 1 is embedded in the connecting hole 7. The shearing force of the fixed pin is accurately calculated, which can not only withstand the impact force of the sliding sleeve in normal operation, but also be sheared off when the set shearing force is reached, realizing the sliding of the inner sliding sleeve 2. Under the action of external force, the inner sliding sleeve 2 slides smoothly after the pin is sheared off, avoiding the jamming phenomenon during sliding, improving the reliability of the opening or closing of the sliding sleeve, ensuring that the inner sliding sleeve 2 remains stable when subjected to unexpected external force, preventing the sliding sleeve from being opened or closed in the non-scheduled position in advance, and avoiding downhole operation accidents.

[0024] In this technical solution, the fracturing sleeves are placed in the formation aligned with the oil and gas layers. Based on the required number of oil and gas layers, a certain number of fracturing sleeves are connected at corresponding positions (intervals). At this time, the inner sleeve 2 seals the blasting hole 3, thus the fracturing sleeves are in a closed state. The inner diameters of multiple fracturing sleeves are consistent. After being lowered into place, cementing is performed. When it is necessary to open the fracturing sleeves, a switch sleeve tool is lowered in using a coiled tubing tool to the predetermined position (generally, opening or closing is done step by step from the deepest level upwards). The switch sleeve tool can be repeatedly set and integrated with the inner sleeve 2, moving the inner sleeve 2 along the outer cylinder. 1. Sliding: After reaching the predetermined position, the tool string is slowly lifted and lowered. The inner diameter of the normal casing is consistent. There is no tonnage load change indicator when the sliding sleeve tool is lowered. When the tool string is lowered, it slides between the inner sliding sleeve 2 and the limit ring 4, causing it to spring open. The position is determined by sensing this spring-opening action and by the lifting and lowering force. The lifting and lowering action generates a certain clamping force, causing a change in tonnage load. This indicates that the convex ring has been engaged in the set position. After determining that it is in place, the sealing is performed. The sliding sleeve tool and the inner sliding sleeve 2 slide downwards together, completing the opening of the fracturing sleeve. Figure 3 As shown, after the blasting hole 3 is opened, the high-volume, high-pressure pumped liquid and proppant enter the formation through the annulus via the blasting hole 3, completing the fracturing. Once the fracturing sleeve opens and completes this stage of fracturing, the tool string is lifted to release the setting seal. The inner sleeve 2 slides, allowing the blasting hole 3 to open and close quickly, facilitating precise control of the timing and extent of fracturing by the operators and improving the accuracy of the fracturing operation. Pulling the tool string in the reverse direction closes the blasting hole 3. By setting a limiting ring 4, it ensures that the tool string is in the correct position and engages with the inner sleeve 2 during setting, and also limits the sliding distance of the inner sleeve 2. This allows the inner sleeve 2 to be pushed back if the fracturing sleeve needs to be closed later, facilitating subsequent downhole operations (such as secondary fracturing or production testing), improving the utilization efficiency of downhole tools, and ensuring the controllability of the fracturing operation.

[0025] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A coiled tubing switchable infinite fracture sleeve, characterized by: The sandblasting device comprises an outer cylinder, a lower joint, and an inner sliding sleeve arranged in the outer cylinder, the lower joint is fixedly connected with the outer cylinder, a plurality of sandblasting holes are formed in the outer cylinder in the circumferential direction, the inner sliding sleeve can make the sandblasting holes flow after sliding, the lower joint is provided with a limiting ring along the sliding direction of the inner sliding sleeve, there is a gap between the limiting ring and the initial position of the inner sliding sleeve, and the inner sliding sleeve abuts against the limiting ring after sliding to the limit position.

2. The coiled tubing switchable infinite fracture sleeve of claim 1, wherein: An alloy ring is embedded at the sandblasting hole.

3. The coiled tubing switchable infinite fracture sleeve of claim 2, wherein: A lock ring is further sleeved on the outer surface of the inner and outer sleeves.

4. The coiled tubing switchable infinite fracture sleeve of claim 3, wherein: The inner sliding sleeve and the outer cylinder are provided with connecting holes in the circumferential direction, and a fixing pin for connecting the inner sliding sleeve and the outer cylinder is embedded in the connecting hole.

5. The coiled tubing switchable infinite fracture sleeve of claim 4, wherein: The number of the sandblasting holes is 18.

6. The coiled tubing switchable infinite fracture sleeve of claim 5, wherein: An upper joint fixedly connected with the outer cylinder is further included.

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