Magnetic suction type drill rod mud scraper

Abstract

The invention relates to a magnetic suction type (or magnetic) drill rod mud scraper which is adsorbed with a drill rod due to the magnetic suction force of the mud scraper, the mud scraper is fixed, and mud can be automatically and completely scraped by lifting the drill rod. The supporting body can be properly changed and can be placed on the upper portion, the middle portion and the lower portion of the rotating disc according to using conditions. The mud scraper can also be made into a built-in type to scrape mud on the inner wall of the drill rod. The mud scraper can also be used for an oil pipe. The mud scraper is safe, reliable, convenient to operate, simple in structure, low in cost and free of external power, can be attached to the drill rod even if being abraded, and mud including the drill rod body and the connector part can be scraped cleanly.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil drilling equipment and relates to a drill pipe scraper for drilling. Background Art

[0002] During the drilling process, the drill bit needs to be replaced after a period of use. This requires the drill pipes to be lifted from the well one by one. The inner and outer surfaces of the pulled-up drill pipes are covered in mud. Failure to scrape the mud away not only wastes the mud but also pollutes the work environment. The drill pipe scraper is designed to address this problem. The most common and long-standing external scraper is a disc-shaped rubber scraper placed under the inner square tile of the turntable. Installation and removal of this scraper require unloading and connecting the drill pipe and hoisting the large square tile. Furthermore, the outer diameter difference of over 40 mm between the drill pipe body and the drill pipe joint easily causes deformation and wear of the scraper when pulling through the drill pipe joint. Over time, the effective diameter increases, resulting in poor scraping performance and failure to meet the requirements for removing mud from the drill pipe body. For these reasons, this type of scraper is now rarely used, and its use is strictly prohibited in many oil fields. To address this "minor" problem, which has been difficult to solve since the development of drilling rigs, many people, including major companies, have devised numerous solutions and applied for numerous related patents both domestically and internationally. Among the most explored technologies, pneumatic scrapers are those that have been used most frequently. A representative example is the "Composite Drill Pipe Scraper" (CN202022107421.8), jointly filed in 2020 by CNPC National Oil and Gas Drilling Equipment Engineering Technology Research Center Co., Ltd., Baoji Petroleum Machinery Co., Ltd., and China National Petroleum Corporation. This scraper primarily removes mud using a "body" consisting of two cylinder heads located on either side of the drill pipe. This system is complex and, while seemingly impressive, is impractical. First, the two cylinders are aligned with the wellhead center, but the drill pipe shifts during the pull-out process and cannot remain centered. Sometimes, it even oscillates violently. If this oscillation is perpendicular to the cylinder axis, it can damage the entire system. Second, such a complex system inevitably requires metal parts. Any metal parts that fall into the well can cause downhole accidents and significantly disrupt drilling operations. Furthermore, it can only be installed on the surface casing at the wellhead, making it difficult to use if a blowout preventer is installed. Furthermore, its manufacturing and operating costs are prohibitive, making widespread use impossible. In reality, the most commonly used scraping tool on site is still a simple scraper made of rubber strips, which is manually scraped by workers. This operation is highly labor-intensive, creates a harsh working environment for operators, wastes mud, pollutes the work environment, and is ineffective. Besides the outer surface of the drill pipe, the inner surface of the drill pipe is also covered with mud during drilling, which also wastes mud and pollutes the environment. In winter, residual drilling fluid on the inner surface of the drill tool can easily cause freezing of the drill water hole. Research reports and patent applications on this topic have been published both domestically and internationally, but due to poor results, it has not been widely used. Summary of the Invention

[0003] The present invention aims to provide a magnetic (or force) drill pipe scraper that is safe, reliable, easy to operate, simple in structure, and low in cost. As an external scraper, with minor modifications, it can be installed at different locations, above, middle, or below the turntable. It requires no external power and remains firmly attached to the drill pipe even after wear, effectively scraping away mud from both the drill pipe body and joints. All components can be made of lightweight, low-hardness materials such as rubber and plastic. Even if a worker accidentally drops a component into the well, it will return to the surface along with the mud. Used as a drill pipe inner wall scraper, it offers a simpler structure and improved effectiveness.

[0004] The present invention is achieved by forming a scraper in the shape of a thin, frustum-shaped cone. The upper base of the cone, at its smallest diameter, is appropriately lengthened and widened parallel to the drill pipe, with an inner diameter equal to or slightly smaller than the outer diameter of the drill pipe being scraped. This is called the "scraper head." It is made of magnetic rubber or plastic, mixed with magnetic powder. The magnetic powder is added and mixed before vulcanization or injection molding, and then magnetized after processing. Magnetic force can also be achieved by filling adhesive or hollow materials with magnetic powder or other magnetic materials. The remainder of the cone serves as a connecting piece supporting the scraper head. It is also made of rubber or plastic, but without the magnetic powder, and therefore lacks magnetism. The scraper head and connecting piece must be integrally formed (or connected). The inner diameter of the cone's lower base, at its largest diameter, must be larger than the outer diameter of the drill pipe joint. The entire cone can be divided axially into several segments, allowing it to open without excessive force when passing through the drill pipe joint. The thin, frustum-shaped connecting piece can also be replaced by several connecting straps or strips arranged along the cone's surface. In addition to the soft cone formed by the connecting piece and scraper head, the scraper must also have a rigid support to support the cone and apply tension during scraping. The support can be integral with the cone. If not, the bottom of the cone must have a thin edge that allows it to be fixed to the support, or holes must be provided in the support for securing the connecting strap. By changing the shape of the support, the magnetic scraper can be placed at different positions on the turntable, such as the top, middle, or bottom, to meet the requirements of different usage conditions. The scraper can also be split in half, eliminating the need to remove the drill pipe and lifting the square tile during installation, reducing installation complexity. In addition to scraping mud from the outer surface of the drill pipe, magnetic scrapers are also well suited for scraping mud from the inner wall. The internal scraper is also designed as a hollow, thin, frustum-shaped cone. The large vertebral base is a magnetic scraper head, while the smaller vertebral base is connected downward to a weighted float. As the drill pipe rises, the weighted float pulls the scraper downward, where the scraper head removes the mud. Once the weighted float sinks into the mud, it floats above it, preventing it from sinking. To avoid mud that might fall into the inverted cone, the connecting piece between the scraper head and the weighted float must have slurry flow openings. Alternatively, the "connecting piece" can be directly made into a "connecting strip." The size of both internal and external scrapers should be adjusted to the size of the drill pipe being scraped.

[0005] The principle of the magnetic scraper can also be used to scrape oil and mud off the oil pipe pulled out during oil well repair. Its structure can be basically the same as that of the drill pipe scraper. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a front cross-sectional view of a single-piece magnetic scraper placed under the turntable square tile.

[0007] FIG. 2 is a top view of FIG. 1 .

[0008] Fig. 3 is the expanded view of A of Fig. 1. It is for representing the oblique section mode of the mud scraper head.

[0009] FIG4 is a partially enlarged view of FIG1 .

[0010] Figure 5 is a front sectional view of a double-plate magnetic scraper placed under the turntable square tile.

[0011] Figure 6 is a top view of Figure 5.

[0012] Figure 7 is a cross-sectional view of another structure of a double-piece magnetic scraper (two large semicircular scraper heads) placed under the square tile of the turntable.

[0013] FIG8 is a top view of FIG7 .

[0014] Figure 9 is a cross-sectional view of another structure of a double-piece magnetic scraper (two scraping heads of the same diameter) placed under the square tile in the turntable.

[0015] Figure 10 is a top view of Figure 9.

[0016] Figure 11 shows a double-piece magnetic scraper placed on a turntable. The single-piece scraper has a similar structure.

[0017] FIG. 12 is a top view of FIG. 11 .

[0018] Figure 13 is a cross-sectional view of the magnetic scraper placed under the turntable.

[0019] FIG. 14 is a top view of FIG. 13 .

[0020] Figure 15 is a cross-sectional view of the drill pipe built-in scraper.

[0021] FIG. 16 is a top view of FIG. 15 .

[0022] In the figure: 1: Mud scraper head 2: Connecting piece (2a: upper connecting piece 2b: lower connecting piece) 3: Mud scraper head 24: Connecting piece 2 5: Support body (5a: upper support body, 5b: lower support body) 6: Locking mechanism 7: Hinge 8: Handle 9: Bracket 10: Weight float 11: Drill rod 12: Tension spring Implementation Method

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. As shown in Figures 1, 5, 7, and 9, they are all magnetic scrapers placed under the square tiles of the turntable. Figure 1 is a single-piece scraper: the scraper is made into a thin-sheet frustum shape, and the upper base of the frustum, that is, the minimum diameter, is appropriately lengthened and thickened parallel to the drill rod, and the inner diameter is equal to or slightly smaller than the outer diameter of the drill rod to be scraped. This is the part (1) marked in the figure: "scraper head". Its material is magnetic rubber or plastic, and is made of rubber or plastic mixed with magnetic powder. The magnetic powder is added and mixed before the rubber is vulcanized or injection-molded, and is magnetized after processing. Magnetic force can also be obtained by filling magnetic materials such as magnetic powder into adhesive or hollow materials. The rest of the frustum is a connecting piece (2) connected to the scraper head (1). Its material is also made of rubber or plastic, but without magnetic powder, so it has no magnetism. The scraper head (1) and the connecting piece (2) must be made (or connected) into one piece. The inner diameter of the bottom of the cone, i.e., the largest diameter, must be larger than the outer diameter of the drill pipe joint. In order to allow the scraper head (1) to pass through the drill pipe joint, the scraper head (1) and the connecting piece (2) need to be split into several pieces (2, 3, 4, 6, etc.). However, the connecting piece (2) does not need to be split all the way to the bottom. The diameter of the connecting piece at the bottom of the split line should be close to and slightly smaller than the diameter of the drill pipe joint, so that the mud on the drill pipe joint can be scraped cleanly at this location. The oblique line of the cone can also be made straight at this location (as shown in Figure 1) to enhance its scraping effect. The split line and the axis of the connecting piece (2) are in the same plane, and the scraper head should be split obliquely as shown in Figure 3 A. The purpose of the oblique split of the scraper head (1) is to allow it to partially overlap. If the interface of the scraper head is a straight line, the scraper head is close to the drill pipe, and the joints of the scraper head must also be close to each other to avoid leaving gaps for mud leakage. However, after a period of use, the scraper head will increase in diameter due to wear, so that the diameter of the scraper head will be larger than the diameter of the drill pipe, resulting in incomplete scraping. In addition to the soft cone formed by the connecting piece (2) and the scraper head (1), the scraper must also have a rigid support body (5) to support the soft cone and apply tension to it when scraping mud. The support body (5) can be made into an integral part with the cone. Alternatively, as shown in Figure (1), it can be made into a combination of an upper support body (5a) and a lower support body (5b). In this case, a thin edge that can be fixed to the support body must be left at the bottom of the cone. With this structure, when the scraper head (1) is damaged, only the scraper head (1) and the connecting piece (2) can be replaced, while the upper and lower support bodies, which are the largest and therefore the most expensive, can continue to be used, thus saving costs to the greatest extent. During the scraping operation, the scraping head (1) is adsorbed on the drill pipe, the upper support body (5a) is supported by the large square tile, and the connection piece (2) is clamped at the connection between the upper support body (5a) and the lower support body (5b). The connection piece (2) pulls the scraping head (1), and the drill pipe rises. The scraping head (1) scrapes away the mud on the surface. When encountering the drill pipe joint, the joint first contacts the connection piece (2), and the connection piece (2) is gradually pushed away with the scraping head (1). The scraping head (1) is then adsorbed on the drill pipe below.Since the drill rod has a slight downward movement when it is supported on the rotary table by the slips, in order to prevent the individual blades of the scraper head from escaping from the magnetic attraction of the drill rod at this time, a thin tension spring (12) can be added to the outside of the scraper head, or one or more upper connecting straps can be added to each section of the scraper head. When the tension of the tension spring (12) is large enough, even if the scraper head has no magnetism, it can still play a certain scraping effect by relying solely on the pressure of the spring. Although its effect is far inferior to that of the magnetic scraper head, it still has a certain scraping effect.

[0024] FIG5 is a double-piece scraper. In the figure, parts (1) and (3) are magnetic scraper heads, parts (2) and (4) are connecting pieces of the scraper heads, and part (5) is a support body that fixes and protects the scraper heads and connecting pieces. The double-piece scraper is actually a combination of two single-piece scrapers. One of the scrapers with a smaller diameter is mainly used to scrape the drill rod, and the larger one is used to scrape the drill rod joint. The scraper head (1), scraper head (3), connecting piece (2), and connecting piece (4) of the double-piece scraper are also divided into several parts. The rest of the parts are the same as those of the single-piece scraper. During the scraping operation, the scraper head (3) is adsorbed on the drill rod, the upper part of the support body (5) supports the large square tile, and the lower part pulls the connecting piece (2) and connecting piece (4). The connecting piece (4) pulls the scraper head (3), and the drill rod rises, and the scraper head (3) scrapes away the mud on the surface. When encountering a drill pipe joint, the joint first contacts the connecting piece (4), and the connecting piece (4) is gradually pushed open with the scraper head (3). However, due to magnetic attraction, the scraper head (3) will be adsorbed on the surface of the joint again, but there may be a gap at the disconnection point where mud is not scraped. At this time, the scraper strip (1) with an inner diameter similar to that of the drill pipe joint is adsorbed on the drill pipe joint. Therefore, the drill pipe joint can also be scraped very cleanly. After the joint travel is completed, the scraper head (3) will be adsorbed on the drill pipe below. A tension spring can also be placed on the outside of the scraper head (3) like a single-piece scraper. The scraper head (1) can be the same as the scraper head (3), but it can also be non-magnetic. It can be slightly smaller in inner diameter than the drill pipe joint. It and the connecting piece (2) are integrated as a whole and are not split into several pieces. In this way, the drill pipe joint can also be scraped cleanly.

[0025] Figure 7 shows two large semicircular scraper heads. They are composed of two magnetic scraper heads (1) that surround half the diameter of the drill pipe (their lengths still slightly overlap when they transition to the drill pipe joint) and an upper connecting belt (2a) and a lower connecting belt group (2b) fixed to the support body (5). When the drill pipe is moved upward, the support body (5) pulls the scraper head (1) adsorbed on the drill pipe through the lower connecting belt (2b) to scrape away the mud. When the joint is reached, due to the length of the scraper head (1), the two scraper heads still partially overlap at the opening, so that the mud will not be scraped away. When the drill pipe is lowered, the upper connecting belt (2a) will pull the scraper head (1) again to prevent it from detaching from the drill pipe.

[0026] Fig. 9 is that two upper and lower scraping mud heads are all the same as the drill pipe external diameter, but the another kind of scheme of its dissecting orientation staggered. This scheme also can use upper and lower connecting band without connecting piece.

[0027] The double-piece scraper can also be made into other forms such as two pieces arranged opposite to each other on the upper and lower sides or three pieces arranged evenly on the upper and lower sides.

[0028] The scraper is made into a single piece, a one-piece type; it can also be made into a split type, split into two halves. The one-piece type has a simple structure and is safer to use, but when loading and unloading, not only does the large square tile need to be lifted, but the drill pipe must also be removed. The split type has a hinge (7) at one opening, and the two separated halves can rotate around the hinge (7), while the other opening has a locking device (6). Therefore, when loading and unloading the split type, it only needs to be put on the drill pipe and then locked with the locking device. Although it does not require lifting the large square tile, the structure is more complicated.

[0029] The magnetic scraper can be placed at different positions, such as the upper, middle or lower position of the turntable, by changing the shape of the support body 5 to meet the requirements of different use conditions.

[0030] Mud scrapers placed above and below the turntable are similar to those placed inside the turntable. The scraper head and connecting piece are essentially the same and can be made of either a single or double piece. Only the supporting structure changes. First, the supporting structure must be split. Second, it must prevent the scraper from falling into the wellbore and from moving up with the drill pipe. For scrapers placed above the surface casing at the wellhead and below the turntable, the supporting structure must be larger than the diameter of the surface casing to prevent it from falling into the wellbore. At the same time, it must be prevented from moving up by the turntable support bars, turntable, or square tiles on the drill floor. For scrapers placed on the turntable, the supporting structure must be larger than the hole in the large square tile to prevent it from falling. It must also be attached to the turntable using its own weight or other methods, such as magnetic attraction, to prevent it from rising with the drill pipe. Furthermore, scrapers placed on the turntable require a manually operated handle or a mechanical push mechanism. Figure 11 shows a magnetic scraper placed on the turntable. Component (6) is a locking mechanism, component (7) is a hinge, and component (8) is an operating handle (which can also be a mechanical pushing device). The operating handle (or mechanical pushing device) can be designed into different shapes. Figure 13 shows a magnetic scraper placed on the surface conduit under the turntable. Component (9) is a bracket. To prevent the scraper from falling into the wellhead and entering the turntable, a bracket (9) larger than the bell mouth and the inner cavity of the turntable is made. The bracket (9) can be connected to the support body (5) and the connecting piece (3) by welding, bonding or other connecting methods.

[0031] Figure 15 shows a magnetic scraper for scraping mud from the inner wall of a drill pipe. The inner scraper is also made into a hollow, thin cone shape, but the large cone bottom is on the top, and the edge of the cone bottom is a magnetic scraper head (1). The small cone bottom is facing downward and connected to the weight float (10). The parts (1) and (10) are connected by a connecting piece (2). Mud may also fall into the cone formed by the scraper head (1) and the connecting piece (10), so some necessary slurry flow ports should be opened. The connecting piece can also be directly converted into a connecting strip, which makes it easier to flow slurry. When the drill pipe rises, the weight float (10) pulls the scraper downward, and the scraper head (1) scrapes away the mud. After the weight float (10) partially sinks into the mud, it floats on the mud and no longer sinks.

[0032] The principle of magnetic scraper can also be used to scrape oil and mud off the tubing during well repair.

[0033] The magnetic scraper has a novel principle, simple structure, and cleanly scrapes mud. Since it is not fixed, changes in the position of the drill pipe, or even its swing, have little effect on it. Due to its simple structure, it can be made entirely of lightweight materials such as rubber or plastic. Due to its light weight, even if it is damaged by misoperation and some fragments fall into the well, they will not fall to the bottom of the well, but will return to the surface with the mud. Depending on the conditions of use, it can be placed in different positions at the top, middle, and bottom of the turntable, which is convenient and practical. Its manufacturing and use costs are very low. Compared with the patent (CN202022107421.8), its manufacturing cost is only a few tens of times that of the patent, and there is no other use cost other than the scraper itself! Human drilling has a nearly 3,000-year history, and modern industrial drilling dates back hundreds of years, but the simple problem of scraping mud from drill pipes has remained largely unsolved. When I first started working in the 1960s, two people each held two sticks and supported a discarded V-belt to scrape mud. Over 50 years later, the world has changed dramatically, but something as simple as scraping mud is still done manually! It's not that the problem is difficult to solve, but that such a simple problem is overly complicated and unworthy! And even complex tools aren't necessarily easy to use! The advent of magnetic scrapers has effectively solved this problem.

Claims

1. A magnetic drill pipe scraper mainly consists of a scraper head, a connecting piece (belt, strip) and a support body, and is characterized by: The scraper head for scraping away mud is magnetic, and the contact pressure required between the scraper head and the drill pipe when scraping away mud on the drill pipe comes from the magnetic attraction between the two.

2. The magnetic drill pipe scraper according to claim 1, characterized in that: The magnetic properties of the scraper head for scraping away mud can be obtained by adding magnetic materials such as magnetic powder to raw materials such as rubber and plastic, or by filling magnetic materials such as magnetic powder into adhesive or hollow materials.

3. The magnetic drill pipe scraper according to claim 1, characterized in that: The main part can be made into a thin-walled frustum shape, a tension spring can be added to the outside of the scraper head, the scraper head and the connecting piece can be cut into several petals, but the diameter of the connecting piece at the bottom of the cutting line should be close to and slightly smaller than the diameter of the drill pipe joint, and the frustum oblique line here can also be partially made into a straight line parallel to the drill pipe.

4. The magnetic drill pipe scraper according to claim 1, characterized in that It can also be made into a two-piece type, one large and one small: the smaller diameter is used to scrape the drill rod, and the larger diameter is used to scrape the drill rod joint. The smaller diameter scraper head can also be split into several pieces, and there can also be a tension spring on its outer side.

5. The magnetic drill pipe scraper according to claim 1, characterized in that: It can be made into a combination of two pieces of the same size arranged up and down: the two scraping heads are basically the same as claim 3, except that the opening direction of each petal is different.

6. The magnetic drill pipe scraper according to claim 1, characterized in that: It can be composed of two magnetic scraper heads which surround most of the drill pipe (their lengths still slightly overlap when they transition to the drill pipe joint) and upper and lower connecting pieces fixed on a support body.

7. The magnetic drill pipe scraper according to claim 1, characterized in that: It can be made into a split type divided into two halves according to the conditions of use and placed on the turntable or on the surface duct opening below the turntable.

8. The magnetic drill pipe scraper according to claim 1, characterized in that: It can also be made into a built-in scraper for the drill pipe to scrape the mud on the inner surface of the drill pipe.

9. The magnetic drill pipe scraper according to claim 1, characterized in that: It can also be used to scrape off oil and mud on the oil pipe during well repair.

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