Sand filling temporary plugging packer releasing sub

Abstract

The utility model provides a temporary plugging packer releasing sub for sand filling. The packer releasing sub comprises a sub body, the body is a tubular hollow structure, the body two ends are integrally formed and provided with a first connecting screw thread and a second connecting screw thread, the body is internally provided with a baffle, the body side wall is provided with a pin hole, a pin is arranged in the pin hole, the body side wall is provided with a plurality of pressure balance seams, and the pressure balance seams are arranged along the body axial direction. The device structure simplifies the fishing operation, solves the problem of differential pressure sticking, improves the success rate of unblocking, reduces the dependence of the traditional structure on special tools, and is stable and reliable in structure.

Description

Technical Field

[0001] This utility model belongs to the field of downhole tools technology in petroleum engineering, specifically relating to the release connector of a temporary plug packer for sand filling. Background Technology

[0002] Oilfield operations often encounter ultra-deep, high-temperature pre-salt reservoirs, with salt layers typically buried at depths of 3000-7000 meters. External forces and chemical corrosion can cause casing deformation and damage, resulting in wells with casing damage. This directly impacts oil and gas production, water injection efficiency, and the service life of oil and water wells. With the number of wells with casing damage increasing annually, the inspection, prevention, and repair of casing damage have become key tasks in oilfield development.

[0003] Casing damage refers to the damage to the casing of oil and water wells due to various reasons, resulting in casing deformation, rupture, or breakage. The main causes of casing damage include geological factors, engineering factors, corrosion factors, and other factors. Geological factors mainly involve crustal movement and fault activity, which cause horizontal or vertical displacement and deformation of the formation, generating enormous compressive and shear forces on the casing, leading to bending, deformation, or even breakage. In structurally complex areas, such as fold belts and near faults, the incidence of casing damage is often higher. Formation pressure changes mainly occur during reservoir production. As oil and gas are continuously extracted, formation pressure gradually decreases, changing the stress in the formation framework and causing formation compaction. This results in uneven pressure on the casing, leading to deformation. Furthermore, during water injection development, excessively high or uneven water injection pressure can also cause abnormal formation pressure distribution, increasing the risk of casing damage. Additionally, different rocks have different mechanical properties and deformation characteristics. If the casing passes through formations with alternating layers of hard and soft soil, the varying degrees of deformation in these layers during extraction will create uneven forces on the casing, making it prone to damage at the interface between the hard and soft layers. Besides this, significant factors occur during the engineering construction process, primarily in seven aspects: First, cementing quality issues: Poor cement slurry performance, uneven cement sheath thickness, and weak bonding between cement and the casing or formation during cementing will result in the casing lacking effective support and protection during subsequent production, making it susceptible to damage from formation pressure and other external forces. Second, collisions and scraping between the drill bit and casing during drilling, as well as improper casing installation, can also cause minor damage and cracks to the casing. These damages may gradually expand during subsequent production, eventually leading to casing failure. Third, the high temperature, high pressure, and impact forces generated during perforation can cause damage to the casing, reducing its local strength. Excessive perforation density, excessively large perforation diameter, or unreasonable perforation phase will further exacerbate the damage to the casing. Fourth, improper production enhancement measures: While fracturing, acidizing, and other production enhancement measures can increase oil well production, improper selection of construction parameters, such as excessively high fracturing pressure or corrosion of the casing by acidizing fluid, can damage the casing. Fifth, formation fluid corrosion: Various corrosive substances in the oil, gas, and water in the formation, such as hydrogen sulfide, carbon dioxide, and chlorides, can react chemically with the casing, gradually corroding the casing wall, reducing its strength and toughness, and leading to perforation, rupture, and other damage. Sixth, the inhomogeneity of the casing material and differences in the formation environment can create different potentials on the casing surface, resulting in electrochemical corrosion. In the humid environment downhole, this electrochemical corrosion will continue, accelerating casing damage. Seventh, during the design phase of oil and water wells, insufficient consideration of formation conditions and production requirements, and the selection of unsuitable casing strength, steel grade, and wall thickness, may lead to the casing being unable to withstand various external forces and corrosion during production, resulting in damage.In pursuit of high production, some oil and water wells may operate under conditions exceeding their design loads for extended periods, causing the casing to withstand pressure and tension beyond its ultimate strength, thus accelerating casing damage. During downhole operations, improper handling of the tubing string can cause scratches and collisions to the casing; using unsuitable workover tools or improper workover techniques can also damage the casing.

[0004] The above reasons must be fully considered in the actual casing damage repair process. In the actual repair of damaged wells, cement grouting repair technology has two major advantages: good sealing effect and relatively low cost. It can effectively seal cracks and pores in the casing, squeezing cement grout into the damaged area and surrounding formation to form a solid cement stone, achieving good sealing and reinforcement, and effectively preventing formation fluid leakage. The main materials required are cement grout, etc., and the material cost is relatively low. Furthermore, the construction equipment and process are relatively simple, and the overall repair cost is lower than other more complex technologies in some cases.

[0005] One commonly used method in the field is the packer-based temporary plugging technique for repairing damaged casing sections. After the packer is lowered to the working depth, sand is filled in its upper part, followed by cementing. Once the cement has solidified, the cement plug in the damaged casing section is drilled out, and the casing inner wall is repaired and pressure tested successfully. Afterward, the packer needs to be retrieved to restore the well's production capacity. The packer retrieval process is crucial. The lowering, setting, unsealing, and removal of the packer must be carried out strictly according to operating procedures, requiring a high level of technical skill and experience from the operators. Improper operation may lead to problems such as insecure packer setting, difficulty in unsealing, or inability to retrieve the packer smoothly, affecting the progress and effectiveness of the entire downhole operation.

[0006] Based on the above problems, there is an urgent need to develop a new type of temporary plugging packer release connector for sand filling, which can be used in mechanical packers and hydraulic packers. The insertion of a retractable slip retrieval cylinder can facilitate effective retrieval. Utility Model Content

[0007] The purpose of this utility model is to provide a release connector for a temporary plug packer used for sand filling, which solves the technical problems of traditional release connectors requiring special retrieval tools, poor tool versatility, high storage costs, and difficulty in releasing the connector in deep well environments due to defects in the snap-fit ​​design.

[0008] The technical solution adopted by this utility model is a temporary plugging packer release connector for sand filling, including a connector body. The body is a tubular hollow structure. The two ends of the body are integrally formed with a first connecting thread and a second connecting thread. A baffle is provided inside the body. A pin hole is provided on the side wall of the body. A pin is inserted through the pin hole. Several pressure balance slots are opened on the side wall of the body. The pressure balance slots extend along the axial direction of the body.

[0009] The features of this utility model also include: There are 6 or 8 pressure balance joints, symmetrically distributed on the upper and lower sides of the pin.

[0010] The pressure balance joints are distributed at equal angles on the outer perimeter wall of the main section.

[0011] The outer periphery of the baffle is provided with several water line grooves. When the baffle is installed on the inner wall of the body, the water line grooves and the inner wall of the body form a passage for liquid to flow through.

[0012] Three waterline channels are set up, distributed at 120° along the outer perimeter of the baffle.

[0013] The diameter of the hole formed by the waterline groove and the inner wall of the main body is φ3mm.

[0014] The first connecting thread is a regular snap, and the second connecting thread is a thick T-shaped reverse snap.

[0015] The pin hole has a stepped hole structure, with the small diameter section fitting with the pin and the large diameter section located on the outside of the body and can be fitted with a sealing component.

[0016] The beneficial effects of this utility model are: ① The temporary packer for sand filling can be released by using a pressure balance joint set in the body to achieve pressure connection between the inside and outside of the tubing during drilling and retrieval, avoiding differential pressure jamming caused by the isolation between the inside and outside of the traditional joint pipe. With the pin design on the upper part of the inner baffle, the pin can be opened by dropping a rod after temporary plugging and sand flushing, forming a "double insurance" differential pressure balance structure, completely eliminating the differential pressure resistance when the packer is released, greatly reducing the risk of release failure, and avoiding complex operations such as subsequent milling and overhaul; ② The second connecting thread with the coarse T-shaped reverse thread design has a smaller torque requirement than the traditional fine thread structure, and can be easily reversed to release the packer in deep well environments. Compared to traditional hydraulic packer setting processes, this method eliminates the need for specialized retrieval tools. A standard 114-116mm retractable slip retrieval tube is sufficient, reducing tool inventory costs. Furthermore, the retrieval tools are highly versatile and reliable, minimizing reliance on operator skill levels. Secondly, it eliminates the need for expensive hydraulic packers, allowing for use with mechanical packers, significantly reducing tool procurement and usage costs. The simple structural design, using a one-piece molding process, minimizes component count and reduces failure rates, minimizing maintenance and replacement costs. It also avoids the additional expenses associated with the wear and tear of specialized tools in traditional processes. Thirdly, the three waterline grooves on the outer periphery of the inner baffle ensure smooth fluid flow during drilling and precise temporary plugging during sand filling, greatly facilitating sand flushing and cleaning of the packer head when retrieval is required, simplifying the operational process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the release joint of the temporary plugging packer for sand filling according to this utility model; Figure 2 This is a schematic diagram of the pressure balance joint distribution of the release joint of the temporary plugging packer for sand filling according to this utility model; Figure 3 This is a schematic diagram of the baffle structure of the release joint of the temporary plugging packer for sand filling according to this utility model.

[0018] In the diagram, 1. Body, 2. First connecting thread, 3. Second connecting thread, 4. Baffle, 5. Pin, 6. Pressure balance joint, 7. Water groove. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] This utility model provides a release connector for a temporary plugging packer used for sand filling, such as... Figures 1-3 As shown, the connector includes a connector body 1, which is a cylindrical hollow tubular structure. Both ends of the body 1 are integrally formed with a first connecting thread 2 and a second connecting thread 3. The connector body 1 is made of 42CrMo alloy structural steel and is a tubular structure with connecting threads at both ends. It possesses high strength and corrosion resistance, adapting to the high-pressure, high-mineralization environment of oil and water wells. Its outer diameter can be φ80mm, and the effective length is generally 0.52m. To adapt to downhole equipment design, the two connecting sections are integrally forged and then machined to avoid weak points caused by welding between the connecting threads and the body, meeting the requirements for tubing string lifting and pressure bearing. A baffle 4 is installed inside the body 1. The internal pipe diameter of the body 1 can be a stepped structure with an upper section of φ52mm and a lower section of φ48mm. The baffle 4 is set on the flange of the stepped inner wall to support the baffle and limit its axial displacement. No additional fasteners are required, facilitating installation and subsequent replacement. The wall thickness can be uniformly set to φ52mm. The baffle 4 is fixed by two parallel steel bars passing through the outer wall inward. The baffle 4 serves to block sand filling and prevent sand from entering the equipment below the packer. The side wall of the main body 1 is provided with pin holes. The pin holes penetrate the pipe wall radially along the main body 1. The pins 5 are inserted through the pin holes. The pins are made of high-strength alloy material, with a diameter of φ8mm and a length that matches the wall thickness of the main body. In the initial state, they seal the internal channel of the main body and the external annulus to maintain the pressure difference between the inside and outside of the tubing string. Several pressure balancing slots 6 are opened on the side wall of the main body. The pressure balancing slots 6 extend along the axial direction of the main body 1. The balancing slots are long strip-shaped through holes used to balance the internal and external pressure of the main body during drop-out operations and drilling, so as to avoid excessive pressure difference that could cause the tubing string to jam. The axial extension design allows the balancing slots to cover a larger area in the length direction of the main body, ensuring that the pressure at different depths can be effectively balanced. The slot length can be 29mm to adapt to the conventional downhole pressure fluctuation range.

[0021] Based on the above structure, there are 6 or 8 pressure balancing seams 6, the number of which is selected according to the wellbore size. 6 seams are used for wells with thinner casing and 8 seams are used for wells with thicker casing, ensuring a balance between pressure balancing efficiency and the strength of the main body structure. They are symmetrically distributed on the upper and lower sides of the pin 5. The symmetrical distribution ensures uniform pressure on both sides of the pin, avoiding pin breakage due to unilateral stress. There are 3 or 4 seams on each side with equal spacing. The pressure balancing seams 6 are distributed at equal angles on the outer peripheral wall of the main body section. When there are 6 balancing seams, the adjacent spacing is 120°, and when there are 8 seams, the adjacent spacing is 90°. The equal angle distribution ensures uniform stress on the main body, avoiding deformation or breakage of the main body due to local stress concentration, while ensuring that the annular fluid can enter the interior of the main body uniformly from all directions.

[0022] The outer periphery of the baffle 4 is provided with several water grooves 7. When the baffle 4 is set on the inner wall of the body 1, the water grooves 7 and the inner wall of the body 1 form a passage for liquid to flow through. Three water grooves 7 are provided, distributed at 120° along the outer periphery of the baffle 4. The aperture formed by the water grooves 7 and the inner wall of the body 1 is φ3mm. The water grooves are notched structures on the edge of the baffle, used to enable liquid flow when the baffle is set inside, avoiding liquid stagnation caused by complete blockage of the baffle. The cross-section of the passage is arc-shaped to ensure liquid flow. It can flow smoothly through the baffle while blocking sand from passing through. During drilling, the well fluid can flow easily. When filling sand after the packer is released, the fine sand flows through the water channel and is temporarily blocked at the baffle position. The design of 3 water channels ensures the flow rate while maximizing the structural strength of the baffle. The φ3mm orifice design can ensure the smooth flow of well washing fluid, well killing fluid and other fluids, while effectively blocking large sand particles from passing through, achieving precise sand blocking. It is compatible with the particle size range of quartz sand used for conventional sand filling.

[0023] Based on the above, the first connecting thread 2 is a positive thread, and the second connecting thread 3 is a coarse T-type reverse thread. The positive thread is a standard thread type, which is tightened by rotating clockwise and matches the female thread of the inserted tubing, facilitating quick connection on site. The thread length is 7cm to ensure sufficient connection strength. The coarse T-type reverse thread is a specially customized thread type with a thread profile angle of 60°. It is tightened by rotating counterclockwise and matches the male thread of the packer. When released, it is separated from the packer by reversing the tubing. The reverse thread design can avoid accidental disengagement caused by downhole vibration of conventional positive threads.

[0024] Based on the above structure, the pin hole is a stepped hole structure. Its small diameter section mates with the pin 5, and the large diameter section is located on the outside of the body 1 and can be fitted with a sealing component. The stepped hole is divided into two sections from the inside to the outside and is formed in one step using a stepped drill. The diameter of the small diameter section is a transition fit with the pin to ensure that the pin is installed firmly and is easy to knock off. The large diameter section can be sealed with a sealing component to prevent mud and sand particles in the well from entering the pin hole and causing the pin to get stuck.

[0025] Example 1 The temporary plugging packer connector for sand filling provided in this embodiment 1 includes a connector body 1, which is a tubular hollow structure. The two ends of the body 1 are respectively integrally formed with a first connecting thread 2 and a second connecting thread 3. A baffle 4 is provided inside the body 1. A pin hole is provided on the side wall of the body 1, and a pin 5 is inserted through the pin hole. Several pressure balance slots 6 are opened on the side wall of the body, and the pressure balance slots 6 extend along the axial direction of the body 1.

[0026] Example 2 The temporary plugging packer connector for sand filling provided in this embodiment 2 includes a connector body 1, which is a tubular hollow structure. The two ends of the body 1 are integrally formed with a first connecting thread 2 and a second connecting thread 3. A baffle 4 is provided inside the body 1. A pin hole is provided on the side wall of the body 1, and a pin 5 is inserted through the pin hole. Several pressure balance slots 6 are opened on the side wall of the body. The pressure balance slots 6 extend along the axial direction of the body 1. There are 6 pressure balance slots 6, which are symmetrically distributed on the upper and lower sides of the pin 5 and distributed at 120° on the outer peripheral wall of the main body section.

[0027] Example 3 The temporary plugging packer connector for sand filling provided in this embodiment 3 includes a connector body 1, which is a tubular hollow structure. The two ends of the body 1 are integrally formed with a first connecting thread 2 and a second connecting thread 3. A baffle 4 is provided inside the body 1. A pin hole is provided on the side wall of the body 1, and a pin 5 is inserted through the pin hole. Several pressure balance slots 6 are opened on the side wall of the body. The pressure balance slots 6 extend along the axial direction of the body 1. There are 8 pressure balance slots 6, which are symmetrically distributed on the upper and lower sides of the pin 5 and distributed at 90° on the outer peripheral wall of the main body section.

[0028] Several water grooves 7 are provided on the outer periphery of the baffle 4. When the baffle 4 is set on the inner wall of the body 1, the water grooves 7 and the inner wall of the body 1 form a passage for liquid to flow through. Three water grooves 7 are provided and distributed at 120° along the outer periphery of the baffle 4.

[0029] Example 4 The temporary plugging packer connector for sand filling provided in this embodiment 4 includes a connector body 1, which is a tubular hollow structure. The two ends of the body 1 are integrally formed with a first connecting thread 2 and a second connecting thread 3. A baffle 4 is provided inside the body 1. A pin hole is provided on the side wall of the body 1, and a pin 5 is inserted through the pin hole. Several pressure balance slots 6 are opened on the side wall of the body. The pressure balance slots 6 extend along the axial direction of the body 1. There are 6 pressure balance slots 6, which are symmetrically distributed on the upper and lower sides of the pin 5 and distributed at 120° on the outer peripheral wall of the main body section.

[0030] Several water grooves 7 are provided on the outer periphery of the baffle 4. When the baffle 4 is set on the inner wall of the body 1, the water grooves 7 and the inner wall of the body 1 form a passage for liquid to flow through. Three water grooves 7 are provided and distributed at 120° along the outer periphery of the baffle 4. The diameter of the hole formed by the water grooves 7 and the inner wall of the body 1 is φ3mm.

[0031] Example 5 The temporary plugging packer connector for sand filling provided in this embodiment 5 includes a connector body 1, which is a tubular hollow structure. The two ends of the body 1 are integrally formed with a first connecting thread 2 and a second connecting thread 3. The first connecting thread 2 is a positive thread, and the second connecting thread 3 is a thick T-shaped reverse thread. A baffle 4 is provided inside the body 1. A pin hole is provided on the side wall of the body 1, and a pin 5 is inserted through the pin hole. Several pressure balance slots 6 are opened on the side wall of the body. The pressure balance slots 6 extend along the axial direction of the body 1. There are 6 pressure balance slots 6, which are symmetrically distributed on the upper and lower sides of the pin 5 and distributed at 120° on the outer peripheral wall of the main body section.

[0032] Several water grooves 7 are provided on the outer periphery of the baffle 4. When the baffle 4 is set on the inner wall of the body 1, the water grooves 7 and the inner wall of the body 1 form a passage for liquid to flow through. Three water grooves 7 are provided and distributed at 120° along the outer periphery of the baffle 4. The diameter of the hole formed by the water grooves 7 and the inner wall of the body 1 is φ3mm.

[0033] Example 6 The temporary plugging packer connector for sand filling provided in this embodiment 6 is based on the above embodiment 5. The pin hole is a stepped hole structure. Its small diameter section is matched with the pin 5, and the large diameter section is located on the outside of the body 1 and is matched with a copper plugging part.

Claims

1. A release connector for a temporary plugging packer used for sand filling, characterized in that, The connector includes a connector body (1), which is a tubular hollow structure. The two ends of the connector body (1) are integrally formed with a first connecting thread (2) and a second connecting thread (3). A baffle (4) is provided inside the connector body (1). A pin hole is provided on the side wall of the connector body (1), and a pin (5) is inserted through the pin hole. Several pressure balance slots (6) are provided on the side wall of the connector body, and the pressure balance slots (6) extend along the axial direction of the connector body (1).

2. The release connector for the temporary plugging packer for sand filling according to claim 1, characterized in that, There are 6 or 8 pressure balance seams (6), which are symmetrically distributed on the upper and lower sides of the pin (5).

3. The release connector for the temporary plugging packer for sand filling according to claim 2, characterized in that, The pressure balance joints (6) are distributed at equal angles on the outer peripheral wall of the main body section.

4. The release connector for the temporary plugging packer for sand filling according to claim 3, characterized in that, The outer periphery of the baffle (4) is provided with several water line grooves (7). When the baffle (4) is set on the inner wall of the body (1), the water line grooves (7) and the inner wall of the body (1) form a passage for liquid to flow through.

5. The release connector for the temporary plugging packer for sand filling according to claim 4, characterized in that, Three waterline channels (7) are provided, which are distributed at 120° along the outer perimeter of the baffle (4).

6. The release connector for a temporary plugging packer for sand filling according to claim 5, characterized in that, The diameter of the hole formed by the waterline groove (7) and the inner wall of the body (1) is φ3mm.

7. The release connector for a temporary plugging packer for sand filling according to claim 6, characterized in that, The first connecting thread (2) is a front thread, and the second connecting thread (3) is a thick T-shaped back thread.

8. The release connector for a temporary plugging packer for sand filling according to claim 1, characterized in that, The pin hole is a stepped hole structure, with its small diameter section cooperating with the pin (5) and its large diameter section located outside the body (1) and can be fitted with a sealing component.

Images