A casing centralizer for cementing in oil extraction

Abstract

This invention relates to the field of cementing equipment technology in oil extraction, specifically a casing centralizer for oil extraction cementing. It includes two identical centralizer mounting bases, a first centralizer mounting base and a second centralizer mounting base. Multiple inner constraint spring plates are distributed between the two bases and combined to form a cylindrical frame. Outer main spring plates are correspondingly located on the outer sides of the inner constraint spring plates. The centralizer also includes a curvature adjustment mechanism and wellbore inner diameter detection and control equipment. The curvature adjustment mechanism drives a sliding column via a hydraulic system, pulling a curvature adjustment rope to adjust the distance between the outer main spring plates and the inner constraint spring plates. This centralizer can dynamically adapt to the outer diameter according to the wellbore inner diameter, providing precise and stable adjustment. It reduces downhole movement friction and component wear, ensuring the casing remains centered, effectively improving cementing construction quality and equipment operational reliability, and adapting to complex and harsh downhole conditions.

Description

Technical Field

[0001] This invention relates to the field of cementing equipment technology for oil extraction, specifically a casing centralizer for cementing in oil extraction. Background Technology

[0002] In cementing operations during oil extraction, the casing centralizer is one of the key pieces of equipment for ensuring cementing quality. Its core function is to keep the casing centered in the wellbore after it has been run into the well, ensuring the formation of a uniform cement sheath between the casing and the wellbore. This achieves formation isolation and protects the casing from formation fluid corrosion and mechanical damage. The downhole environment in oil extraction is characterized by high pressure, high temperature, large temperature fluctuations, and irregular wellbore diameters that may contain corrosive media. The wellbore diameter typically varies over a wide range, requiring the casing centralizer to not only possess sufficient structural strength and corrosion resistance to adapt to harsh working conditions, but also to flexibly adapt to different wellbore diameters, ensuring stable and reliable centralizing support throughout the entire casing running and cementing process.

[0003] Existing casing centralizers for oil well cementing are mostly designed with a fixed outer diameter or have a limited adjustment range, making it difficult to adapt to the changing inner diameter of different wellbore walls under complex well conditions. This results in the centralizer not fitting tightly against the wellbore or getting stuck, affecting the casing centering accuracy. Some adjustable centralizers use mechanical manual adjustment, which has low adjustment accuracy, slow response speed, and cannot dynamically optimize adjustment parameters according to real-time downhole conditions. At the same time, traditional centralizers lack a real-time detection and feedback mechanism for the inner diameter of the wellbore, the status of the hydraulic system, and vibration during the adjustment process. It is difficult to detect and resolve abnormal problems in a timely manner during the adjustment process, resulting in unstable centralization effect and affecting the quality of cementing operations. Therefore, in view of the above situation, there is an urgent need to develop a casing centralizer for oil well cementing to overcome the shortcomings in current practical applications. Summary of the Invention

[0004] The purpose of this invention is to provide a casing centralizer for cementing in oil extraction, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A casing centralizer for cementing in oil extraction includes a centralizer mounting base one and a centralizer mounting base two.

[0007] Multiple inner constraint spring plates are distributed between the first and second fixing bases of the centralizer. The first fixing base, the inner constraint spring plates and the second fixing base of the centralizer are combined to form the cylindrical frame of the sleeve centralizer.

[0008] Each inner constraint spring sheet is provided with an outer main spring sheet on its outer side, and the two ends of the outer main spring sheet are respectively fixedly connected to the first and second stabilizer fixing seats.

[0009] The system also includes a curvature adjustment mechanism, which is connected to the first stabilizer mounting base, the inner constraint spring plate, and the second stabilizer mounting base, and is connected to the outer main spring plate. The mechanism is used to adjust the distance between the outer main spring plate and the inner constraint spring plate according to the size of the wellbore inner diameter, so as to realize the change of the outer diameter of the casing stabilizer.

[0010] As a further aspect of the present invention: the first stabilizer fixing seat and the second stabilizer fixing seat have the same structure;

[0011] Both the first and second fixing bases of the centralizer are provided with multiple reinforcing protrusions.

[0012] As a further aspect of the present invention: multiple anti-collision rollers are rolled on the reinforcing protrusion to reduce the friction between the first and second centralizer mounting seats and the well wall when the casing centralizer moves forward.

[0013] As a further aspect of the present invention: the elastic effect of the outer main spring sheet is greater than the elastic effect of the inner constraint spring sheet;

[0014] During the forward movement of the casing centralizer, the outer main spring plate is bound to the surface of the inner constraint spring plate. After the casing centralizer is in position, the distance between the outer main spring plate and the inner constraint spring plate is adaptively adjusted by the curvature adjustment mechanism according to the size of the inner diameter of the well wall at the position.

[0015] As a further aspect of the present invention: the curvature adjustment mechanism includes:

[0016] The hydraulic system control oil pipe is connected to the centralizer fixing seat and is connected to an external hydraulic system through a pipeline.

[0017] A hydraulic control chamber is provided on the inner constraint spring sheet;

[0018] The hydraulic control chamber is connected to the hydraulic system control oil pipe through an oil inlet hole, which is located on the inner constraint spring sheet.

[0019] And a restraint assembly, which is connected to the outer main spring sheet and the hydraulic control chamber respectively, for binding the outer main spring sheet to the surface of the inner restraint spring sheet during the forward movement of the casing centralizer.

[0020] As a further aspect of the present invention: the restraint state component includes:

[0021] A sliding column, which is slidably mounted within the hydraulic control chamber;

[0022] The number of the threading holes is multiple, and all of the multiple threading holes are opened on the inner layer constraint spring sheet and are connected to the hydraulic control cavity;

[0023] And a curvature adjustment cord, one end of which is fixedly connected to the outer main spring plate, and the other end of which passes through the thread hole and is fixedly connected to the sliding column.

[0024] As a further aspect of the present invention, it also includes: a receiving groove, wherein the receiving groove is formed on one side wall of the sliding column;

[0025] During the process of the sliding column pulling the curvature adjustment rope, the curvature adjustment rope is housed in the receiving groove.

[0026] And baffle heads, which are distributed at both ends of the sliding column to ensure the space at both ends of the sliding column is sealed.

[0027] As a further aspect of the present invention, it also includes: a second oil inlet hole, which is located on the inner layer constraint spring sheet at one end away from the first oil inlet hole and is connected to the hydraulic control cavity;

[0028] And a compensation control oil pipe, which is connected to the oil inlet port and connected to an external hydraulic system via a pipeline.

[0029] As a further aspect of the present invention, it also includes multiple wellbore inner diameter detection and control devices, which are respectively fixedly installed on stabilizer mounting base one and stabilizer mounting base two, and are connected to the external hydraulic system signal.

[0030] The wellbore inner diameter detection and control equipment includes:

[0031] The core detection module for the inner diameter of the well wall adopts a high-temperature and high-pressure resistant ultrasonic ranging sensor.

[0032] The hydraulic system oil pressure detection module integrates a high-precision pressure sensor and is connected to the hydraulic control chamber, oil inlet port one, and oil inlet port two.

[0033] The vibration detection module is adjusted by using a miniature piezoelectric vibration sensor, which is fixedly mounted on the outer main spring plate;

[0034] The data preprocessing and filtering module has a built-in IIR low-pass filtering algorithm;

[0035] The data normalization processing module uses the min-max normalization algorithm;

[0036] The logic judgment and instruction generation module is used to generate hydraulic system adjustment instructions based on preset thresholds.

[0037] The signal transmission module adopts the RS485 bus communication protocol;

[0038] The power management module features a wide voltage input design and built-in overvoltage, overcurrent, and short-circuit protection units.

[0039] As a further aspect of the present invention: the working process of the wellbore inner diameter detection and control device includes the following steps in sequence:

[0040] (1) Power-on initialization and parameter calibration: After the equipment is lowered into the well along with the casing centralizer, it completes the self-test of each module and performs zero-point and range calibration of the ultrasonic ranging sensor, pressure sensor and vibration sensor based on the preset calibration parameters.

[0041] (2) Real-time data acquisition: Each detection module collects wellbore distance data, hydraulic control chamber oil pressure data and outer main spring plate vibration acceleration data at regular intervals. All raw data are transmitted to the data preprocessing and filtering module.

[0042] (3) Data filtering and noise reduction: The collected raw data is processed by the IIR low-pass filtering algorithm to obtain the purified detection data;

[0043] (4) Data normalization processing: The min-max normalization algorithm is used to convert the filtered data into standardized data within a set range;

[0044] (5) Logical judgment and instruction generation: Based on the preset adaptation threshold, oil pressure safety threshold and vibration allowable threshold, judgment is made to generate corresponding hydraulic system adjustment instructions related to oil supply, pressure relief or adjustment rate;

[0045] (6) Signal transmission and execution feedback: The adjustment command is sent to the external hydraulic system via RS485 bus, the hydraulic system execution status feedback signal is received and the corresponding subsequent operation is executed;

[0046] (7) Cyclic monitoring and dynamic optimization: The filter coefficient and adjustment rate are automatically optimized based on the fluctuation of historical standardized data by continuously monitoring the cycle period.

[0047] Compared with the prior art, the beneficial effects of the present invention are:

[0048] Through the coordinated action of the curvature adjustment mechanism, the outer main spring plate, and the inner constraint spring plate, combined with the real-time monitoring of the well wall inner diameter detection and control equipment, the distance between the outer main spring plate and the inner constraint spring plate can be flexibly adjusted according to the size of the well wall inner diameter at different locations downhole, so as to realize the dynamic change of the outer diameter of the centralizer within a wide range, effectively adapting to the irregular well wall size under complex well conditions, and ensuring that the casing is always centered.

[0049] The hydraulic system drives the curvature adjustment mechanism, and with the IIR low-pass filtering algorithm, min-max normalization algorithm and RS485 bus communication protocol, it can accurately collect, process and transmit data on well wall inner diameter, hydraulic system oil pressure and adjustment vibration. It can quickly generate and execute appropriate hydraulic adjustment commands, and at the same time, the bidirectional hydraulic circuit ensures the stability of the adjustment process and avoids adjustment lag or abnormal vibration problems.

[0050] The reinforced protrusions on the centralizer mounting base are equipped with anti-collision rollers, which convert the sliding friction between the mounting base and the well wall into rolling friction, significantly reducing the frictional resistance during the centralizer's lowering process and minimizing wear between the equipment and the well wall. Meanwhile, the core components are made of corrosion-resistant and wear-resistant materials such as Q345B low-alloy high-strength steel, 60Si2MnA high-strength spring steel, and 304 stainless steel, combined with anti-corrosion coating treatment, improving the equipment's durability and reliability under harsh downhole conditions.

[0051] The wellbore inner diameter detection and control equipment integrates a variety of high-precision sensors and data processing modules, enabling fully automated operation of the entire process, including power-on self-test calibration, real-time data acquisition, filtering and noise reduction, logical judgment, command generation, and loop optimization. It can automatically optimize the filtering coefficient and adjustment rate based on historical data, promptly avoid risks such as excessive oil pressure and abnormal vibration, ensure the stability and reliability of the straightening process, and effectively improve the quality of cementing construction.

[0052] The centralizer fixing base one and centralizer fixing base two are symmetrical in structure. Together with multiple evenly distributed inner constraint spring plates, they form a stable cylindrical frame. The outer main spring plate is made of high-strength spring steel and has a greater elastic effect than the inner constraint spring plate. While providing flexible adjustment capability, it ensures the overall structural strength and support rigidity of the centralizer and avoids equipment deformation and failure under high pressure conditions downhole. Attached Figure Description

[0053] Figure 1 This is a three-dimensional structural diagram of a casing centralizer for cementing in oil extraction, as described in an embodiment of the present invention.

[0054] Figure 2 This is a three-dimensional structural diagram of the distribution of inner constraint spring sheets in an embodiment of the present invention.

[0055] Figure 3This is a schematic diagram of the main structure of the curvature adjustment rope in an embodiment of the present invention.

[0056] Figure 4 This is a top view of the structure of the centering device fixing seat in an embodiment of the present invention.

[0057] Figure 5 This is a three-dimensional structural diagram of the distribution of the outer main spring sheets in an embodiment of the present invention.

[0058] Figure 6 This is a schematic diagram of the structure of the first and second stabilizer fixing seats in an embodiment of the present invention.

[0059] Figure 7 This is an enlarged structural schematic diagram of the inner constraint spring sheet in an embodiment of the present invention.

[0060] Figure 8 This is a three-dimensional structural diagram of the hydraulic control chamber in an embodiment of the present invention.

[0061] Figure 9 This is a three-dimensional structural diagram of the threading hole in an embodiment of the present invention.

[0062] Figure 10 This is a partial cross-sectional view of the inner constraint spring sheet in an embodiment of the present invention.

[0063] Figure 11 This is a three-dimensional structural diagram of the sliding column in an embodiment of the present invention.

[0064] Figure 12 This is a three-dimensional structural diagram of the receiving groove in an embodiment of the present invention.

[0065] Figure 13 This is a flowchart illustrating the operation of the wellbore inner diameter detection and control device in an embodiment of the present invention.

[0066] In the diagram: 1-Center fixing seat one, 2-Hydraulic system control oil pipe, 3-Well wall inner diameter detection and control equipment, 4-Anti-collision roller, 5-Outer main spring plate, 6-Curvature adjustment rope, 7-Inner constraint spring plate, 8-Center fixing seat two, 9-Compensation control oil pipe, 10-Reinforcing protrusion, 11-Oil inlet hole one, 12-Hydraulic control cavity, 13-Sliding column, 14-Wire hole, 15-Oil inlet hole two, 16-Accommodation groove, 17-Baffle head. Detailed Implementation

[0067] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0068] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0069] Please see Figures 1-13 The present invention provides a casing centralizer for cementing in oil extraction, comprising a centralizer fixing seat 1 and a centralizer fixing seat 2 8.

[0070] Multiple inner constraint spring plates 7 are distributed between the centralizer fixing seat 1 and the centralizer fixing seat 2. The centralizer fixing seat 1, the inner constraint spring plates 7 and the centralizer fixing seat 2 form a cylindrical frame of the casing centralizer. The centralizer fixing seat 1 and the centralizer fixing seat 2 are made of Q345B low alloy high strength steel. The whole structure is a ring structure. The outer diameter is designed to be 200-300mm according to the commonly used casing specifications, the inner diameter is 150-250mm, and the thickness is 30-40mm to ensure stable support under high pressure conditions downhole.

[0071] Each inner constraint spring sheet 7 is provided with an outer main spring sheet 5 on its outer side. The two ends of the outer main spring sheet 5 are respectively fixedly connected to the centralizer fixing seat 1 and the centralizer fixing seat 2. The outer main spring sheet 5, as the core centralizing component, is designed for the high-pressure (0-50MPa), large temperature difference (-20℃~150℃), and corrosive media conditions in oil well cementing. The material is 60Si2MnA high-strength spring steel, with a hardness of HRC42-48 after tempering, an elastic modulus of 2000-2200N / mm, a single sheet width of 40-50mm, a thickness of 8-10mm, and a length determined according to… The spacing between the centralizer fixing seats is designed to be 300-400mm. Both ends are connected to centralizer fixing seat 1 and centralizer fixing seat 2 8 by welding. The weld joint is reinforced with fillet welds, and the weld height is not less than 6mm. It can withstand no less than 1000 elastic deformation cycles without failure. The inner constraint spring plate 7 is made of 304 stainless steel spring strip to avoid corrosion by downhole corrosive media. The elastic coefficient is 800-1000N / mm, the width is 30-35mm, the thickness is 4-6mm, and the length is the same as the outer main spring plate 5. It is connected to the fixing seat by M8×20 stainless steel bolts. Two bolts are symmetrically distributed at each connection point to ensure connection stability.

[0072] The system also includes a curvature adjustment mechanism, which is connected to the centralizer fixing seat 1, the inner constraint spring plate 7, and the centralizer fixing seat 8, and is connected to the outer main spring plate 5. The mechanism is used to adjust the distance between the outer main spring plate 5 and the inner constraint spring plate 7 according to the size of the well wall inner diameter, so as to realize the change of the outer diameter of the casing centralizer.

[0073] With centralizer fixing seat 1 and centralizer fixing seat 2 as the core support components, the multiple inner constraint spring plates 7 distributed between them cooperate with each other to form a stable cylindrical frame for the casing centralizer, providing the structural foundation for the entire device. The outer main spring plate 5 is correspondingly set outside the inner constraint spring plate 7, and its two ends are fixedly connected to the two fixing seats. With its high elastic coefficient of 2000-2200N / mm brought by its 60Si2MnA high-strength spring steel material, it has the initial ability to adapt to the well wall. The curvature adjustment mechanism, through its connection with centralizer fixing seat 1, centralizer fixing seat 2, inner constraint spring plate 7 and outer main spring plate 5, becomes the core actuator for outer diameter adjustment. Addressing the shortcomings of traditional casing centralizers in oil well cementing, which often have fixed outer diameters or limited adjustment ranges and are difficult to adapt to different wellbore inner diameters under complex well conditions, this invention addresses these issues. The curvature adjustment mechanism dynamically adjusts the distance between the outer main spring plate 5 and the inner constraint spring plate 7 according to the actual wellbore inner diameter. This allows for flexible changes in the outer diameter of the casing centralizer, enabling it to adapt to wellbore sizes ranging from 150-500 mm. This effectively avoids the poor centralizing effect or jamming problems caused by the poor adaptability of traditional centralizers, ensuring the casing remains centered throughout the cementing process and guaranteeing the quality of subsequent cementing operations.

[0074] In one embodiment of the present invention, please refer to Figures 1-13 The structure of the first stabilizer fixing seat 1 is the same as that of the second stabilizer fixing seat 8;

[0075] Both the first and second fixing seats of the centralizer are provided with multiple reinforcing protrusions 10. The reinforcing protrusions 10 are integrally formed with the fixing seats. The height of a single protrusion is 50-60mm and the width is 60-70mm. 6-8 protrusions are evenly distributed on each fixing seat. The central angle between two adjacent reinforcing protrusions 10 is 45-60°. After sandblasting and rust removal, the outer surface is coated with an epoxy resin anti-corrosion coating with a thickness of 0.3-0.5mm to improve corrosion resistance.

[0076] Multiple anti-collision rollers 4 are rolled on the reinforced protrusion 10 to reduce the friction between the centralizer fixing seat 1 and centralizer fixing seat 2 and the well wall when the casing centralizer moves forward. The anti-collision rollers 4 are made of polyurethane elastomer with a Shore hardness of 90-95A, an outer diameter of 60-80mm, an inner diameter of 30-40mm, and are fitted with a No. 45 steel bushing. The bushing is clearance-fitted with the 40Cr material rotating shaft on the reinforced protrusion 10 (clearance 0.03-0.06mm). The rotating shaft diameter is 25-30mm to ensure flexible rolling, converting sliding friction into rolling friction, and reducing the coefficient of friction to below 0.1.

[0077] Please see Figure 1 and Figure 2 The elastic effect of the outer main spring sheet 5 is greater than the elastic effect of the inner constraint spring sheet 7;

[0078] During the forward movement of the casing centralizer, the outer main spring plate 5 is bound to the surface of the inner constraint spring plate 7. After the casing centralizer is in place, the distance between the outer main spring plate 5 and the inner constraint spring plate 7 is adaptively adjusted by the curvature adjustment mechanism according to the size of the inner diameter of the well wall at the placement point.

[0079] By adopting the same structural design for both the centralizer mounting base 1 and the centralizer mounting base 2, the symmetry and uniformity of the force on the device are ensured. Multiple reinforcing protrusions 10, with their integrated molding structure and 50-60mm protrusion height, significantly enhance the structural strength and load-bearing capacity of the mounting base, preventing deformation or damage under high pressure and complex working conditions downhole, thus extending the service life of the centralizer. Addressing the issue of high sliding friction and easy wear between the mounting base and the well wall during traditional centralizer movement, the anti-collision rollers 4, rolled on the reinforcing protrusions 10, utilize polyurethane elastomer material and 45# steel bushings to convert sliding friction into rolling friction, reducing the friction coefficient to below 0.1. This significantly reduces frictional resistance during the centralizer's forward movement and minimizes wear between the centralizer mounting base 1 / 2 and the well wall. Simultaneously serving as a guide and anti-collision element, ensuring the smooth descent of the centralizer; the outer main spring plate 5, made of 60Si2MnA high-strength spring steel with an elastic coefficient of 2000-2200 N / mm, is greater than the inner constraint spring plate 7, made of 304 stainless steel spring strip with an elastic coefficient of 800-1000 N / mm. During the forward movement of the centralizer, the outer main spring plate 5 is bound to the surface of the inner constraint spring plate 7, ensuring the stability of the centralizer's outer diameter during movement and preventing jamming caused by arbitrary deformation of the outer spring plate. When the centralizer reaches the designated position, the outer main spring plate 5, under the action of the curvature adjustment mechanism, adaptively adjusts the distance between itself and the anti-collision roller 4 according to the actual size of the well wall's inner diameter at the location. With its stronger elastic recovery force, it tightly adheres to the well wall, providing reliable centralizing support for the casing and improving the casing's centering accuracy during cementing.

[0080] In one embodiment of the present invention, please refer to Figures 1-13 The curvature adjustment mechanism includes:

[0081] The hydraulic system control oil pipe 2 is connected to the centralizer fixing seat 1 and is connected to the external hydraulic system through a pipeline. The hydraulic system control oil pipe 2 is made of 304 stainless steel seamless steel pipe with an outer diameter of 16mm and a wall thickness of 3mm. The pipe fitting adopts GB / T3765-2008 compression fitting and the pressure resistance rating is not less than 35MPa.

[0082] The hydraulic control cavity 12 is formed on the inner constraint spring sheet 7; the cross-section of the hydraulic control cavity 12 is similar to a rectangle, with a length of 200-250mm and an internal surface roughness of Ra0.8μm to ensure smooth sliding.

[0083] The hydraulic control chamber 12 is connected to the hydraulic system control oil pipe 2 through an oil inlet hole 11. The oil inlet hole 11 has a diameter of 10-12mm and a 45° chamfer on the hole wall to avoid hydraulic oil eddies.

[0084] And a restraint assembly, which is connected to the outer main spring plate 5 and the hydraulic control chamber 12 respectively, for restraining the outer main spring plate 5 on the surface of the anti-collision roller 4 during the forward movement of the sleeve centralizer.

[0085] The restraint state component includes:

[0086] The sliding column 13 is slidably installed in the hydraulic control cavity 12; the sliding column 13 is made of 45 steel, with chrome plating on the surface (thickness 0.05-0.1mm), and its outer diameter is clearance-fitted with the hydraulic control cavity 12 (clearance 0.02-0.05mm), and its length is 180-220mm;

[0087] Multiple wire-passing holes 14 are provided, each located on the inner constraint spring sheet 7 and connected to the hydraulic control cavity 12. Each inner constraint spring sheet 7 has 3-4 wire-passing holes 14 with a diameter of 12-14 mm. The inner wall of the hole is inlaid with a brass bushing (inner diameter 10-12 mm) with an interference fit of 0.05-0.1 mm to reduce wear on the pull rope.

[0088] And a curvature adjustment pull rope 6, one end of which is fixedly connected to the outer main spring plate 5, and the other end of which passes through the thread hole 14 and is fixedly connected to the sliding post 13; the curvature adjustment pull rope 6 is made of ultra-high molecular weight polyethylene fiber braided rope with a diameter of 6-8mm, a breaking strength ≥50kN, and a surface coated with polytetrafluoroethylene (friction coefficient ≤0.15). It is wedge-shaped and fixed to the outer main spring plate 5, and connected to the sliding post 13 by a 10mm diameter 40Cr pin.

[0089] Please see Figures 7-12 It also includes: a receiving groove 16, which is formed on one side wall of the sliding column 13; the receiving groove 16 has a width of 10-12mm, a depth of 8-10mm, and a length of 150-180mm, and is used to store the pull rope when tightening.

[0090] During the process of the sliding column 13 pulling the curvature adjustment rope 6 to move, the curvature adjustment rope 6 is housed in the receiving groove 16.

[0091] And baffle heads 17, which are distributed at both ends of the sliding column 13 to ensure the space at both ends of the sliding column 13 is sealed; the baffle heads 17 are made of nitrile rubber (Shore hardness 70-80A) and are connected to the sliding column 13 by an interference fit of 0.1-0.2mm to seal both ends of the hydraulic control chamber 12.

[0092] The hydraulic system control oil pipe 2 is made of 304 stainless steel seamless steel pipe, which connects the centralizer fixing seat 1 to the external hydraulic system, providing a stable power source for the entire curvature adjustment mechanism. The hydraulic control chamber 12 is opened on the inner constraint spring plate 7, with a rectangular cross section of 25mm×15mm and an inner surface roughness of Ra0.8μm, forming a high-quality execution space for hydraulic drive. The oil inlet hole 11 is designed with a diameter of 10-12mm and a 45° chamfer to avoid hydraulic oil eddies, together forming a high-efficiency hydraulic control basic circuit; combined with existing technology The manual adjustment of the centralizer's outer diameter during surgery suffers from complex operation, low precision, and inability to be adjusted in real time. The restraint assembly, through the cooperation of the sliding post 13, the threading hole 14, and the curvature adjustment rope 6, achieves precise restraint and release of the outer main spring plate 5. The sliding post 13 is made of chrome-plated 45# steel and maintains a 0.02-0.05mm gap with the hydraulic control chamber 12 to ensure smooth sliding. The threading hole 14 is inlaid with a brass bushing to reduce rope wear. The curvature adjustment rope 6 is made of ultra-high molecular weight polyethylene fiber braided rope, with a ≥5% curvature adjustment capability. A fracture strength of 0 kN and a friction coefficient of ≤0.15 ensure reliable transmission. When the casing centralizer moves forward, the external hydraulic system supplies oil to the hydraulic control chamber 12 via the hydraulic system control oil pipe 2, pushing the sliding column 13 along the hydraulic control chamber 12. This, in turn, pulls the curvature adjustment rope 6 to tighten, firmly binding the outer main spring plate 5 to the surface of the inner constraint spring plate 7, preventing unnecessary deformation and jamming of the outer main spring plate 5 due to irregular well walls during forward movement. Simultaneously, the receiving groove 16 on the sliding column 13 has a groove width of 10-12 mm. With a length of 150-180mm, the curvature adjustment pull rope 6 can be neatly stored during the tightening process, preventing the pull rope from getting tangled or interfering with other components, ensuring the smoothness of the adjustment process. The baffle heads 17 at both ends of the sliding column 13 are made of nitrile rubber, which effectively seals the space at both ends of the hydraulic control chamber 12 through interference fit, avoiding hydraulic oil leakage, ensuring stable hydraulic system pressure, and thus ensuring constant tension of the curvature adjustment pull rope 6. This achieves reliable control over the binding state of the outer main spring plate 5, improving the accuracy and stability of the outer diameter adjustment.

[0093] In one embodiment of the present invention, please refer to Figures 1-12 It also includes: oil inlet hole 2 15, which is opened on the inner constraint spring sheet 7 at one end away from oil inlet hole 1 11 and is connected to the hydraulic control cavity 12; the specifications of oil inlet hole 2 15 are the same as those of oil inlet hole 1 11, with a hole diameter of 10-12mm and a 45° chamfer.

[0094] And a compensation control oil pipe 9, which is connected to the oil inlet hole 15 and connected to the external hydraulic system through a pipeline; the compensation control oil pipe 9 and the hydraulic system control oil pipe 2 have the same specifications, both being 304 stainless steel seamless steel pipes, to ensure the consistency and reliability of the bidirectional hydraulic circuit.

[0095] An oil inlet hole 2 15 is opened at the end of the inner constraint spring plate 7 away from the oil inlet hole 11. This hole has the same 10-12mm diameter and 45° chamfer design as the oil inlet hole 11, and is connected to the compensation control oil pipe 9 and the external hydraulic system. The compensation control oil pipe 9 is made of the same 304 stainless steel seamless pipe as the hydraulic system control oil pipe 2, forming a symmetrical and stable bidirectional hydraulic oil supply circuit. This bidirectional circuit can effectively improve the stability and response speed of the hydraulic system (and can control the deformation degree of the outer main spring plate 5 to adapt to different wells). The inner diameter of the wall ensures the best support effect for the casing. In actual operation, when the hydraulic system control oil pipe 2 supplies oil to the hydraulic control chamber 12 through the oil inlet 11 to push the sliding column 13 to move, the compensation control oil pipe 9 can provide auxiliary oil supply through the oil inlet 15 to ensure the pressure balance at both ends of the sliding column 13, avoid pressure fluctuations caused by unilateral oil supply, and make the adjustment response of the outer main spring plate 5 more rapid and accurate. It effectively avoids the adjustment lag problem that may occur in a single oil circuit, and improves the adaptability and centralization reliability of the casing centralizer under complex well conditions.

[0096] In one embodiment of the present invention, please refer to Figures 1-13 It also includes: well wall inner diameter detection and control device 3, the number of well wall inner diameter detection and control devices 3 is multiple, the multiple well wall inner diameter detection and control devices 3 are respectively fixedly installed on the centralizer fixing seat 1 and the centralizer fixing seat 2 8, and the well wall inner diameter detection and control device 3 is also connected to the external hydraulic system signal;

[0097] The specific components of the wellbore inner diameter detection and control device 3 are as follows:

[0098] The core detection module for the wellbore inner diameter uses high-temperature and high-pressure resistant ultrasonic ranging sensors (compatible with downhole temperatures ranging from -20℃ to 150℃ and pressure environments of 0-50MPa). These sensors are evenly distributed on centralizer mounting base 1 and centralizer mounting base 2, with at least 3 sensors installed on each mounting base (symmetrically distributed at 120°). By emitting ultrasonic signals and receiving reflected signals from the wellbore, the distance data between the wellbore and the sensors is collected in real time, providing the original basis for calculating the wellbore inner diameter.

[0099] Hydraulic system oil pressure detection module: integrates a high-precision pressure sensor, which is connected to the hydraulic control chamber 12, oil inlet 11, and oil inlet 15 through an interface. It collects oil pressure data in the hydraulic control chamber 12 in real time (measurement range 0-60MPa, accuracy ±0.5%FS), and simultaneously monitors the oil pressure fluctuations of the hydraulic system control oil pipe 2 and compensation control oil pipe 9 to ensure the pressure stability of the hydraulic adjustment process and control the curvature change of the outer main spring plate 5.

[0100] The vibration detection module is adjusted by using a miniature piezoelectric vibration sensor, which is fixedly installed in the middle of the outer main spring plate 5 (one sensor for each outer main spring plate 5). It collects the vibration acceleration data of the outer main spring plate 5 in real time during the deformation adjustment process (measurement range 0-50g, frequency response 10-1000Hz) to judge the smoothness of the adjustment action and whether there are problems such as jamming or abnormal deformation, so as to ensure the straightening effect.

[0101] Data preprocessing and filtering module: Built-in IIR low-pass filtering algorithm to filter the acquired raw wellbore inner diameter data, oil pressure data and vibration acceleration data, remove electromagnetic interference and mechanical noise and other clutter signals in the downhole environment, retain effective data characteristics, and provide a clean data source for subsequent processing.

[0102] Data normalization processing module: used to convert detection data of different dimensions and scales (well inner diameter: 150-500mm; oil pressure: 0-60MPa; vibration acceleration: 0-50g) into standardized data of the same scale, which is convenient for subsequent logical judgment and command output.

[0103] Logic judgment and instruction generation module: Based on the normalized detection data, combined with the preset well wall inner diameter adaptation threshold, oil pressure safety threshold and vibration allowable threshold, it judges the current adaptation status between the outer diameter of the centralizer and the inner diameter of the well wall, and generates the corresponding hydraulic system adjustment instructions (oil supply / pressure relief, oil supply amount and adjustment rate, etc.).

[0104] Signal transmission module: Adopts industrial-grade RS485 bus communication protocol (adapted to long-distance transmission in underground wells, with strong anti-interference ability) to realize bidirectional signal interaction with external hydraulic system. On the one hand, it uploads detection data to hydraulic system controller, and on the other hand, it receives status feedback signals from hydraulic system.

[0105] Power management module: Adapted to the underground power supply environment, it adopts a wide voltage input (12-24VDC) design and has built-in overvoltage, overcurrent and short circuit protection units to provide stable power supply for each detection module, processing module and transmission module, ensuring that the equipment can work continuously under harsh conditions.

[0106] The working process of the wellbore inner diameter detection and control device 3 is as follows:

[0107] Step 1: Equipment Initialization and Parameter Calibration

[0108] After the wellbore inner diameter detection and control device 3 is lowered into the well along with the casing centralizer, it first performs power-on initialization, and each module completes self-test (sensor, communication and power status detection).

[0109] Based on preset calibration parameters (standard range of well inner diameter 150-500mm, standard working range of oil pressure 0-35MPa, and allowable vibration ≤10g), zero-point calibration and range calibration are performed on the ultrasonic ranging sensor, pressure sensor, and vibration sensor to ensure detection accuracy.

[0110] Step 2: Real-time data acquisition

[0111] Each detection module is activated. The core detection module for well wall inner diameter uses ultrasonic sensors to collect well wall distance data every 50ms. The average value of the data collected by the three sensors simultaneously is taken as the raw data of the current well wall radius (R). raw ), and calculate the original data of the wellbore inner diameter (D) raw =2×R raw );

[0112] The hydraulic system oil pressure detection module collects raw oil pressure data (P) from the hydraulic control chamber 12 every 30ms. raw );

[0113] The vibration detection module is adjusted to collect raw vibration acceleration data (A) of the outer main spring plate 5 every 40ms. raw );

[0114] All the raw data collected is transmitted to the data preprocessing and filtering module in real time.

[0115] Step 3: Data preprocessing (filtering and noise reduction)

[0116] IIR low-pass filtering algorithm is used for D raw P raw A raw The filtering process is performed, and the filtering formula is as follows:

[0117] y(n)=a0×x(n)+a1×x(n-1)+a2×x(n-2)-b1×y(n-1)-b2×y(n-2);

[0118] Where x(n) is the original data at the current moment, and x(n-1) and x(n-2) are the original data at the previous two moments; y(n) is the filtered data at the current moment, and y(n-1) and y(n-2) are the filtered data at the previous two moments; a0=0.25, a1=0.5, a2=0.25, b1=0.5, b2=0.25 (the optimal filtering coefficients verified under downhole working conditions);

[0119] After filtering, the purified wellbore inner diameter data D, oil pressure data P, and vibration acceleration data A are obtained.

[0120] Step 4: Data normalization processing

[0121] The min-max normalization algorithm is used to convert the filtered D, P, and A into standardized data in the 0-1 interval. The specific formula is as follows:

[0122]

[0123] Where x' is the normalized data (range 0-1); x is the filtered original detection data (corresponding to D, P, and A respectively); x min The preset minimum value of this parameter (D) min =150mm, P min =0MPa, A min =0g); x max The default maximum value for this parameter (D) max =500mm, P max =60MPa, A max =50g);

[0124] The wellbore inner diameter standardized data D', oil pressure standardized data P', and vibration standardized data A' were calculated respectively.

[0125] Step 5: Logic Judgment and Adjustment Instruction Generation

[0126] Preset judgment threshold: Adaptation threshold T D =0.8 (corresponding to a wellbore inner diameter of 430mm; when D'>0.8, the outer diameter of the centralizer needs to be increased; when D'<0.2, the outer diameter needs to be decreased), oil pressure safety threshold T P =0.58 (corresponds to an oil pressure of 35MPa; pressure relief is required when P' > 0.58), vibration allowable threshold T A =0.2 (corresponds to a vibration acceleration of 10g; when A'>0.2, the adjustment rate needs to be reduced);

[0127] Logical Judgment 1 (Inner Diameter Adaptation Judgment): If D'∈[0.2,0.8], it is determined that the current outer diameter of the centralizer is adapted and no adjustment is needed; if D'>0.8, it is determined that the outer diameter needs to be increased, and the command "hydraulic system control oil pipe 2 depressurizes + compensation control oil pipe 9 supplies oil" is generated, with the oil supply amount being proportional to (D'-0.8); if D'<0.2, it is determined that the outer diameter needs to be decreased, and the command "hydraulic system control oil pipe 2 supplies oil + compensation control oil pipe 9 depressurizes" is generated, with the oil supply amount being proportional to (0.2-D').

[0128] Logic judgment 2 (oil pressure safety judgment): If P' > 0.58, the "bidirectional oil pipe pressure relief" command is generated first, and the inner diameter adaptation adjustment command is executed after P' ≤ 0.58.

[0129] Logic judgment 3 (vibration stability judgment): If A'>0.2, generate the instruction "reduce adjustment rate by 50%", and simultaneously maintain the current oil pressure stability. After A'≤0.2, restore the normal adjustment rate.

[0130] Step 6: Signal Transmission and Execution Feedback

[0131] The adjustment command generated by the logic judgment module is sent to the external hydraulic system through the signal transmission module (RS485 bus), and the hydraulic system performs oil supply, pressure relief or rate adjustment actions according to the command;

[0132] After the hydraulic system performs the action, it sends the execution status signal (success / failure / execution) back to the well wall inner diameter detection and control device 3 through the signal transmission module;

[0133] If a "successful execution" signal is received, return to step 2 to continue collecting data in real time; if a "failed execution" signal is received, the device will issue an alarm signal and repeatedly send the adjustment command 3 times. If it still fails, the adjustment will stop and the current state will be locked; if a "in progress" signal is received, wait 500ms and then return to step 2 to collect data and monitor parameter changes during the adjustment process.

[0134] Step 7: Loop Monitoring and Dynamic Optimization

[0135] The entire workflow follows a cycle of "acquisition-preprocessing-normalization-judgment-execution-feedback" (single cycle ≤ 300ms), enabling real-time dynamic monitoring of the wellbore inner diameter, hydraulic system status, and vibration regulation.

[0136] After every 10 iterations, the variance of the fluctuation of each parameter is calculated based on historical normalized data:

[0137]

[0138] in, The average of 10 data points is used. If the variance is ≤0.01, the current operating condition is considered stable, and the adjustment parameters are maintained. If the variance is >0.01, the filter coefficient and adjustment rate are automatically optimized to improve the adaptation accuracy and stability.

[0139] Through the above-mentioned software modules and workflow, the wellbore inner diameter detection and control device 3 can achieve accurate perception, data processing and dynamic adjustment of complex downhole working conditions. It works in conjunction with the mechanical structures (centralizer fixing seat, spring plate and hydraulic control chamber, etc.) recorded in the document to ensure that the outer diameter of the casing centralizer is adapted to the inner diameter of the wellbore in real time, thereby improving the reliability and quality of cementing operations.

[0140] It should be noted that, in this invention, unless otherwise explicitly specified and limited, the terms "sliding," "rotating," "fixed," and "equipped" should be interpreted broadly. For example, they can refer to welded connections, bolted connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0141] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A casing centralizer for oil well cementing, comprising a centralizer mounting base one and a centralizer mounting base two, characterized in that: Multiple inner constraint spring plates are distributed between the first and second fixing bases of the centralizer. The first fixing base, the inner constraint spring plates and the second fixing base of the centralizer are combined to form the cylindrical frame of the sleeve centralizer. Each inner constraint spring sheet is provided with an outer main spring sheet on its outer side, and the two ends of the outer main spring sheet are respectively fixedly connected to the first and second stabilizer fixing seats. The system includes a curvature adjustment mechanism, which is connected to the first stabilizer mounting base, the inner constraint spring plate, and the second stabilizer mounting base, and is also connected to the outer main spring plate. The mechanism is used to adjust the distance between the outer main spring plate and the inner constraint spring plate according to the size of the wellbore inner diameter, so as to realize the change of the outer diameter of the casing stabilizer. The curvature adjustment mechanism includes: a hydraulic system control oil pipe, which is connected to the centralizer fixing seat and connected to an external hydraulic system through a pipeline; A hydraulic control chamber is provided on the inner constraint spring sheet; The hydraulic control chamber is connected to the hydraulic system control oil pipe through an oil inlet hole, which is located on the inner constraint spring sheet. And a restraint state assembly, which is connected to the outer main spring sheet and the hydraulic control chamber respectively, and is used to restrain the outer main spring sheet on the surface of the inner restraint spring sheet during the forward movement of the casing centralizer; The restraint assembly includes a sliding column, which is slidably mounted within the hydraulic control chamber. The number of the threading holes is multiple, and all of the multiple threading holes are opened on the inner layer constraint spring sheet and are connected to the hydraulic control cavity; And a curvature adjustment cord, one end of which is fixedly connected to the outer main spring plate, and the other end of which passes through the thread hole and is fixedly connected to the sliding column.

2. The casing centralizer for oil well cementing according to claim 1, characterized in that, The structure of the first stabilizer fixing seat is the same as that of the second stabilizer fixing seat; Both the first and second fixing bases of the centralizer are provided with multiple reinforcing protrusions.

3. The casing centralizer for oil well cementing according to claim 2, characterized in that, Multiple anti-collision rollers are rolled on the reinforcing protrusion to reduce the friction between the first and second centralizer mounting seats and the well wall when the casing centralizer moves forward.

4. The casing centralizer for oil well cementing according to any one of claims 1-3, characterized in that, The elastic effect of the outer main spring sheet is greater than that of the inner constraint spring sheet; During the forward movement of the casing centralizer, the outer main spring plate is bound to the surface of the inner constraint spring plate. After the casing centralizer is in position, the distance between the outer main spring plate and the inner constraint spring plate is adaptively adjusted by the curvature adjustment mechanism according to the size of the inner diameter of the well wall at the position.

5. The casing centralizer for oil well cementing according to claim 1, characterized in that, Also includes: A receiving groove is formed on one side wall of the sliding column; During the process of the sliding column pulling the curvature adjustment rope, the curvature adjustment rope is housed in the receiving groove. And baffle heads, which are distributed at both ends of the sliding column to ensure the space at both ends of the sliding column is sealed.

6. The casing centralizer for oil well cementing according to claim 5, characterized in that, Also includes: Oil inlet hole two is located on the inner layer constraint spring sheet at one end away from oil inlet hole one and is connected to the hydraulic control cavity; And a compensation control oil pipe, which is connected to the oil inlet port and connected to an external hydraulic system via a pipeline.

7. The casing centralizer for oil well cementing according to claim 6, characterized in that, It also includes multiple wellbore inner diameter detection and control devices, which are respectively fixedly installed on stabilizer mounting base one and stabilizer mounting base two, and are connected to the external hydraulic system signal; The wellbore inner diameter detection and control equipment includes: The core detection module for the inner diameter of the well wall adopts a high-temperature and high-pressure resistant ultrasonic ranging sensor. The hydraulic system oil pressure detection module integrates a high-precision pressure sensor and is connected to the hydraulic control chamber, oil inlet port one, and oil inlet port two. The vibration detection module is adjusted by using a miniature piezoelectric vibration sensor, which is fixedly mounted on the outer main spring plate; The data preprocessing and filtering module has a built-in IIR low-pass filtering algorithm; The data normalization processing module uses the min-max normalization algorithm; The logic judgment and instruction generation module is used to generate hydraulic system adjustment instructions based on preset thresholds. The signal transmission module adopts the RS485 bus communication protocol; The power management module features a wide voltage input design and built-in overvoltage, overcurrent, and short-circuit protection units.

8. The casing centralizer for oil well cementing according to claim 7, characterized in that, The workflow of the wellbore inner diameter detection and control equipment includes the following steps: (1) Power-on initialization and parameter calibration: After the equipment is lowered into the well along with the casing centralizer, it completes the self-test of each module and performs zero-point and range calibration of the ultrasonic ranging sensor, pressure sensor and vibration sensor based on the preset calibration parameters. (2) Real-time data acquisition: Each detection module collects wellbore distance data, hydraulic control chamber oil pressure data and outer main spring plate vibration acceleration data at regular intervals. All raw data are transmitted to the data preprocessing and filtering module. (3) Data filtering and noise reduction: The collected raw data is processed by the IIR low-pass filtering algorithm to obtain the purified detection data; (4) Data normalization processing: The min-max normalization algorithm is used to convert the filtered data into standardized data within a set range; (5) Logical judgment and instruction generation: Based on the preset adaptation threshold, oil pressure safety threshold and vibration allowable threshold, judgment is made to generate corresponding hydraulic system adjustment instructions related to oil supply, pressure relief or adjustment rate; (6) Signal transmission and execution feedback: The adjustment command is sent to the external hydraulic system via RS485 bus, the hydraulic system execution status feedback signal is received and the corresponding subsequent operation is executed; (7) Cyclic monitoring and dynamic optimization: The filter coefficient and adjustment rate are automatically optimized based on the fluctuation of historical standardized data by continuously monitoring the cycle period.

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