Low-torque reamer while drilling

Abstract

The invention discloses a low-torque reamer while drilling, and belongs to the technical field of well drilling. The low-torque reamer while drilling comprises a body, a plurality of convex body structures are symmetrically formed in the middle of the periphery of the body, a peripheral groove is formed in each convex body, a blade is embedded in each peripheral groove, and wear-resistant rings, limiting blocks and wedge-shaped blocks are sequentially and symmetrically arranged at the two ends of each blade; gauge protection teeth are further distributed on the convex body around the peripheral groove. Friction torque caused by borehole profile changes, borehole spirals and dogleg degrees is reduced through the design of the rotatable blades, the stick-slip phenomenon and downhole vibration are effectively restrained, the mechanical drilling speed is increased, the borehole quality is effectively improved, and the stability of the drilling environment is enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of drilling technology, and particularly relates to a low-torque while-drilling reamer. BACKGROUND

[0002] With the extension of oil and gas exploration and development to deep formations and complex structure regions, the operation demand of extended reach drilling and complex well trajectory (such as horizontal well, multi-lateral well) has significantly increased. Such drilling engineering faces technical challenges such as high precision requirement of well trajectory control, sharp increase of downhole friction torque, and intensified risk of wellbore instability. Especially under the adverse working conditions of wellbore diameter reduction and extremely hard abrasive formation, the conventional reamer generally has problems such as large torque fluctuation, fast tool wear, and difficult maintenance of wellbore quality, which seriously restricts the drilling efficiency and operation safety.

[0003] In the prior art, the conventional reamer mainly adopts a fixed blade wing structure or a mechanical diameter expansion device, and the design has the following technical bottlenecks: first, in the extended reach well and complex well trajectory, the traditional reamer is prone to nonlinear growth of friction torque due to the large contact area between the drilling tool and the well wall. For example, irregular profiles such as wellbore helix and dogleg angle can cause stick-slip vibration of the drilling tool system, further aggravate torque fluctuation, and affect the stability of the while-drilling measurement tool. Second, for the severely reduced diameter well section, the existing reamer lacks an active torque regulation mechanism, and the strong friction between the reduced diameter well wall and the drilling tool often causes a sudden increase in torque, and even causes a stuck pipe accident. In addition, in the extremely hard abrasive formation (such as granite, quartz sandstone), the fixed system of the blade wing of the conventional reamer is prone to structural failure due to high-frequency vibration, and the wear rate of the sealed bearing assembly is fast, which makes it difficult to meet the demand of continuous operation in long well sections, and frequent tripping to replace the tool significantly increases the operation time.

[0004] In terms of wellbore quality control, the conventional reamer has insufficient adaptability to stepped cuttings of the formation, and is prone to generate asymmetric load during cutting, which causes the wellbore trajectory to deviate from the designed size, especially in the intersection section of the multi-lateral well, which is prone to form local diameter reduction or abnormal diameter expansion. In addition, the gauge protection tooth layout and tool fixing method of the existing reamer are difficult to maintain a stable full-size cutting section under abrasive conditions, and the continuous attenuation of the wellbore size causes serious hidden dangers to subsequent well completion operations. SUMMARY

[0005] The present application relates to the field of drilling technology, and particularly relates to a low-torque while-drilling reamer.

[0006] The present application is implemented by adopting the following technical solutions.

[0007] The application discloses a low-torque while-drilling reamer, which comprises a body, a plurality of convex structures are symmetrically formed in the middle part of the outer periphery of the body, an outer periphery groove is formed on each convex structure, a blade wing is embedded in the outer periphery groove, and a wear-resistant ring, a limiting block and a wedge-shaped block are symmetrically arranged at two ends of the blade wing in sequence; and a gauge protection tooth is distributed on the convex structure around the outer periphery groove.

[0008] Further, a thread for connecting other tools is arranged at the upper end and the lower end of the body.

[0009] Further, a semicylindrical groove matched with the outer periphery of the blade wing is formed in the middle part of the outer periphery groove of the body downwards; and a convex platform matched with the wedge-shaped block is arranged at two ends in the outer periphery groove.

[0010] Further, the blade wing comprises a mandrel, a blade wing body is sleeved on the mandrel, a bearing sleeve is arranged between the mandrel and the blade wing body, a certain number of spiral grooves are arranged on the outer periphery of the blade wing body, and a cutting tooth is arranged between the spiral grooves.

[0011] Still further, a mud ring and a sealing ring are further arranged between the mandrel and the blade wing body, and the mud ring is located outside the sealing ring.

[0012] Still further, the outer periphery of the mandrel is smaller in the middle part than at two ends, a circular hole communicating with an inner hole is arranged in the middle part of the outer periphery of the mandrel, the inner hole of the mandrel is filled with lubricating oil, and a pin is arranged at two ends of the mandrel.

[0013] Further, the limiting block is an irregular hexagonal table body structure matched with the outer periphery groove of the body, is connected with the body through a fixed pin, and the lower part of the limiting block is a conical structure and is provided with a circular hole matched with the mandrel; and the outer periphery of the limiting block is provided with a cutting tooth.

[0014] Further, the wedge-shaped block is a slanting quadrilateral table body structure and is connected with the body through a fixed bolt; and the lower part of the wedge-shaped block is provided with a groove matched with the convex platform in the outer periphery groove of the body.

[0015] The application has the following beneficial effects.

[0016] The application adopts a blade wing rotatable bearing design, three rotatable blade wings provide a stable point for reducing the torque of a drill string, and the influence of the downhole torque is reduced to the maximum extent, and the advantages mainly include the following five points.

[0017] (1) The downhole torque is significantly reduced, the friction torque caused by the change of the borehole profile, the borehole spiral and the dogleg degree is reduced through the rotatable blade wing design, the drilling power transmission is optimized, and the operation stability is improved.

[0018] (2) The drilling environment stability is enhanced, the stick-slip phenomenon and the downhole vibration are effectively inhibited through the reduction of the torque, the rate of penetration is improved, the service life of the while-drilling measurement tool is prolonged, and the overall operation efficiency is improved.

[0019] (3) Effective improvement of wellbore quality, low-torque while-drilling reamer can effectively deal with formation step-shaped cuttings, maintain regular shape of wellbore, reduce irregular problems of well wall, and ensure wellbore quality.

[0020] (4) Strong adaptability to abrasive conditions, longer full-size cutting section and reliable cutter wing fixing system are adopted, the low-torque while-drilling reamer can work normally under such harsh conditions when encountering extremely hard abrasive formations, thereby reducing tool replacement frequency and improving drilling efficiency.

[0021] (5) The wedge block cooperates with the limiting block to ensure that the cutter will not fall in the wellbore during long-stroke drilling. The tapered geometry of the fixed wedge composed of the wedge block and the limiting block presses the cutter wing block into the body, providing a reliable anchoring point for cutter wing fixation. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic diagram of the present application; Figure 2 is a top view of the present application; Figure 3 is a sectional view of the cutter wing of the present application; Figure 4 is a structural schematic diagram of the cutter wing of the present application; Figure 5 is a structural schematic diagram of the body of the present application; Figure 6 is a three-dimensional structural schematic diagram of the body of the present application; Figure 7 is a structural schematic diagram of the limiting block of the present application; Figure 8 is a structural schematic diagram of the wedge block of the present application; Figure 9 is a schematic diagram of the while-drilling tool combination rotating when contacting the well wall in the downhole.

[0023] Wherein, 1. body, 2. wedge block, 3. limiting block, 4. wear-resistant ring, 5. cutter wing, 6. fixed pin, 7. fixed bolt, 8. gauge stabilizer, 9. mandrel, 10. mud baffle, 11. sealing ring, 12. cutter wing body, 13. bearing sleeve, 14. cutting tooth, 15. pin. DETAILED DESCRIPTION

[0024] The present patent application is further described below in conjunction with the drawings and examples.

[0025] As shown in Figures 1-9 , a low-torque while-drilling reamer includes a body 1, a cutter wing 5, a wear-resistant ring 4, a limiting block 3, a wedge block 2, a fixed pin 6, a fixed bolt 7, and a gauge stabilizer 8.

[0026] The blade wing 5, the wear ring 4, the limiting block 3 and the wedge block 2 are arranged in the outer circumferential groove of the body 1, the wear ring 4, the limiting block 3 and the wedge block 2 are symmetrically arranged on the upper and lower ends of the blade wing 5 in sequence and are in contact with the inner wall of the outer circumferential groove of the body 1, and the gage teeth 8 are distributed in the middle part of the outer circumference of the body 1.

[0027] Specifically, the body 1 is a hollow cylindrical structure, the outer diameter of the middle part is greater than that of the upper part and the lower part, the upper end and the lower end of the body 1 are respectively provided with threads for connecting other tools. The middle part of the outer circumference of the body 1 is provided with three V-shaped grooves to divide the middle part of the body 1 into three equal convex structures, each convex structure is provided with an outer circumferential groove, the outer circumferential groove is in the shape of a long dumbbell with rounded ends and a narrowed middle part, and the middle part of the outer circumferential groove forms a semicylindrical groove in contact with the outer circumference of the blade wing 5 downward, for placing the blade wing 5. The two ends of the outer circumferential groove of the body 1 are provided with bosses matched with the wedge block 2, the bosses and the groove bottom of the outer circumferential groove near the middle side of the bosses are respectively provided with threaded holes, the threaded holes are respectively used for penetrating the fixing bolts 7 and the fixing pins 6, so as to fix the wedge block 2 and the limiting block 3. A plurality of round holes for installing the gage teeth 8 are arranged on the outer part of the outer circumferential groove of the convex structure.

[0028] The blade wing 5 is arranged in the semicylindrical groove in the outer circumferential groove of the body 1, and the outer circumference of the blade wing 5 slightly protrudes the outer diameter of the body 1. The blade wing 5 comprises a blade wing body 12, a cutting tooth 14, a mud ring 10, a sealing ring 11, a bearing sleeve 13, a mandrel 9 and a pin 15. The mandrel 9 and the bearing sleeve 13 are arranged in the blade wing body 12, the blade wing body 12 can rotate around the mandrel 9, the cutting tooth 14 is arranged on the outer circumference of the blade wing body 12, and the pin 15 is arranged on the inner circumference of the mandrel 9; the mud ring 10 and the sealing ring 11 are arranged between the mandrel 9 and the blade wing body 12, the mud ring 10 is installed in the front groove in the inner circumference of the blade wing body 12, and the sealing ring 11 is installed behind the groove of the mud ring 10.

[0029] Specifically, the blade wing body 12 is a hollow cylindrical structure, a certain number of spiral grooves are arranged on the outer circumference, round holes for installing the cutting tooth 14 are arranged between the spiral grooves, the inner circumference of the blade wing body 12 has a symmetric feature, grooves for installing the mud ring 10 and the sealing ring 11 are respectively arranged on the upper part of the inner circumference, the inner diameter of the middle upper part is greater than that of the upper part and the middle part, and the bearing sleeve 13 is installed.

[0030] The mandrel 9 is a hollow cylindrical structure, the outer diameter of the middle part is smaller than that of the two ends, a round hole communicating with the inner hole is arranged on the middle part of the outer circumference, and threads for installing the pin 15 are arranged on the two ends of the inner circumference; the inner hole of the mandrel 9 is filled with lubricating oil, the two ends are sealed by the pin 15, and the lubricating oil is beneficial to the rotation of the blade wing body 12 around the mandrel 9.

[0031] The limiting block 3 is an irregular hexagonal table body structure matched with the outer circumferential groove of the body 1. The lower part of the limiting block 3 is a conical structure and is provided with a circular hole matched with the mandrel 9. The outer circumference of the limiting block 3 is provided with a circular hole for mounting the cutting tooth 14. The upper part of the outer circumference is provided with a stepped hole for mounting the fixing pin 6 to fix the limiting block 3 to the body 1.

[0032] The wedge block 2 is a slanting quadrilateral table body structure. The lower part is provided with a groove matched with the inner boss of the outer circumferential groove of the body 1. The upper part is a cylindrical surface and is provided with a stepped hole penetrating to the groove for mounting the fixing bolt 7 to fix the wedge block 2 to the body 1.

[0033] The wedge block 2 presses the blade 5 into the groove of the body 1 in cooperation with the limiting block 3. The fixing bolt 7 and the fixing pin 6 are respectively mounted in the circular hole of the wedge block 2 and the circular hole of the limiting block 3 to be fixed to the body 1.

[0034] When drilling operation is performed, the low-torque while-drilling reamer is lowered into the preset position together with the drill bit to start the drilling operation. In the face of complex well conditions caused by wellbore profile, wellbore helix and dogleg, when the drilling tool rotates clockwise, the three blades 5 of the while-drilling reamer can rotate counterclockwise around the mandrel 9, which maximally reduces the surface area of friction and thus reduces the torque caused by the bottom hole assembly. The three rotating blades 5 can provide a stable point for the drill string to reduce the torque, so that the drilling process can be prolonged and the transmission of the drilling pressure to the drill bit can be improved in the complex wellbore geometry of the extended reach drilling. The gauge teeth 8 of the body 1 rotate clockwise with the drilling tool, and the cutting teeth 14 of the blade 5 rotate counterclockwise with the blade 5. During the rotation, the gauge teeth 8 and the cutting teeth 14 can grind the wellbore to process the small dogleg, wellbore helix and stratigraphic stepped cuttings, so as to realize the mechanical wellbore trimming.

[0035] The embodiments of the specific embodiment are the preferred embodiments of the present application, but do not limit the protection scope of the present application. Therefore, any equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A low-torque reamer while drilling, characterized in that: The body (1) is characterized in that: a number of convex structures are symmetrically formed in the middle of the outer periphery of the body (1), and an outer periphery groove is formed on each convex structure. A blade (5) is embedded in the outer periphery groove. A wear-resistant ring (4), a limiting block (3) and a wedge block (2) are symmetrically arranged at both ends of the blade (5). A diameter-protecting tooth (8) is also distributed on the convex structure around the outer periphery groove.

2. The low-torque reamer as described in claim 1, characterized in that: The upper and lower ends of the body (1) are respectively provided with threads for connecting other tools.

3. The low-torque reamer as described in claim 1, characterized in that: The outer periphery groove of the body (1) forms a semi-cylindrical groove that matches the outer periphery of the blade (5) in the middle; and the two ends of the outer periphery groove are provided with protrusions that cooperate with the wedge block (2).

4. A low-torque reamer as described in claim 1, characterized in that: The blade (5) includes a spindle (9), the spindle (9) is fitted with a blade body (12), and a bearing sleeve (13) is provided between the spindle (9) and the blade body (12); a certain number of spiral grooves are provided on the outer periphery of the blade body (12), and cutting teeth (14) are provided between the spiral grooves.

5. A low-torque reamer as described in claim 4, characterized in that: A mudguard ring (10) and a sealing ring (11) are also provided between the spindle (9) and the blade body (12), with the mudguard ring (10) located outside the sealing ring (11).

6. A low-torque reamer as described in claim 4, characterized in that: The outer diameter of the mandrel (9) is smaller than that of its two ends in the middle of its outer periphery. A circular hole is provided in the middle of the outer periphery to connect with the inner hole. The inner hole of the mandrel (9) is filled with lubricating oil. Pins (15) are provided at both ends of the mandrel (9).

7. A low-torque reamer as described in claim 1, characterized in that: The limiting block (3) is an irregular hexagonal platform structure that matches the outer circumferential groove of the body (1) and is connected to the body (1) by a fixing pin (6); the lower part of the limiting block (3) is a conical structure and is provided with a round hole that cooperates with the spindle (9); the outer circumference of the limiting block (3) is provided with cutting teeth (14).

8. A low-torque reamer as described in claim 1, characterized in that: The wedge block (2) is a slanted quadrilateral platform structure, which is connected to the body (1) by fixing bolts (7); the lower part of the wedge block (2) is provided with a groove that matches the inner boss of the outer circumference groove of the body (1).

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