Underground drilling tool combination for coal-bed gas well landing

Abstract

The utility model discloses an underground drilling tool assembly for landing of a coal-bed gas well, which is characterized in that the upper end of a PDC (Polycrystalline Diamond Compact) drill bit is screwed with a single-bent screw, the upper end of the single-bent screw is screwed with a one-way valve, the upper end of the one-way valve is screwed with a sitting key joint, an inner cavity of the sitting key joint is provided with a direction finder, the upper end of the sitting key joint is screwed with a non-magnetic drill collar, and the upper end of the non-magnetic drill collar is provided with a centralizer; a common drill collar is screwed above the non-magnetic drill collar, and a heavy weight drill rod is screwed above the common drill collar; five blades are arranged on the crown portion of the PDC drill bit and comprise three long blades and two short blades, the inner end of the first long blade extends to the axis of the drill bit, and the inner ends of the second long blade and the third long blade are close to the axis of the drill bit. A first short blade is arranged between the first long blade and the second long blade, and a second short blade is arranged between the third long blade and the first long blade. The drilling tool assembly is accurate in deflecting and orientation, the drill bit is high in overall aggressiveness, tooth arrangement is optimized, the service life of the drill bit is prolonged, and the single-trip footage is prolonged.

Description

Technical Field

[0001] The utility model relates to a drilling tool in the oil drilling industry, in particular to a downhole drilling tool assembly for landing a coal bed gas well, belonging to the technical field of downhole drilling tools. Background Art

[0002] At present, the formation conditions of deep coalbed methane wells are relatively complex. Usually, there are abrasive formations above the landing formation of coalbed methane wells. The dense structure of hard sandstone has poor drillability, resulting in poor penetration of the drill bit. It is also possible to drill softer mudstone, resulting in sticky slip or mud packing of the drill bit at the bottom of the well. For example, the Ф215.9mm traditional PDC drill bit used before the landing of the Linxing deep coalbed methane well encountered the following problems during the construction process: 1. In the complex formations such as Liujiagou, Shiqianfeng Formation, Upper and Lower Shihe Formation, Shanxi Formation, and Taiyuan Formation, the drill bit was not effective, the drill bit was worn quickly, and the life was short, and the expected effect was not achieved; 2. The impact resistance of the main teeth is not suitable for the landing formation of the coalbed methane well; 3. The cutting tooth angle is about 30°, which is not conducive to rock breaking; 4. The drill bit is designed in a parabola, the drill bit is not stable enough, and it is not adaptable to the formation characteristics; 5. The arrangement of the drill bit waterway and water hole cannot fully and effectively increase the water horsepower to quickly remove the cuttings from the bottom of the well. Utility Model Content

[0003] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and utility model name of this application to avoid blurring the purpose of this section, specification abstract and utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0004] In view of the above problems and / or the problems existing in the prior art, the present utility model is proposed.

[0005] The purpose of the utility model is to overcome the problems existing in the prior art and provide a downhole drilling tool combination for landing a coalbed methane well, which has accurate inclination and orientation, strong overall aggressiveness of the drill bit, optimized tooth arrangement, increased drill bit life, and extended single-trip footage.

[0006] In order to solve the above technical problems, the utility model provides a downhole drilling tool assembly for landing a coalbed methane well, comprising a PDC drill bit, the upper end of which is screwed with a single-bend screw, the upper end of which is screwed with a one-way valve, the upper end of which is screwed with a key joint, the inner cavity of which is equipped with a directional instrument, the upper end of which is screwed with a non-magnetic drill collar, the upper end of which is provided with a centralizer, the upper end of which is screwed with an ordinary drill collar, and the upper end of which is screwed with a weighted drill pipe;

[0007] The crown of the PDC drill bit is provided with five blades, including three long blades and two short blades. The inner end of the first long blade wing extends to the drill bit axis, and the inner ends of the second long blade wing and the third long blade wing are close to the drill bit axis; the first short blade wing is arranged between the first long blade wing and the second long blade wing, and the second short blade wing is arranged between the third long blade wing and the first long blade wing.

[0008] As an improvement of the present invention, the phase angle between the first long blade wing cutting surface and the second long blade wing cutting surface is 125°, the phase angle between the second long blade wing cutting surface and the third long blade wing cutting surface is 93°, and the phase angle between the third long blade wing cutting surface and the first long blade wing cutting surface is 142°.

[0009] As a further improvement of the present invention, the phase angle between the first long blade wing cutting surface and the first short blade wing cutting surface is 57°, and the phase angle between the third long blade wing cutting surface and the second short blade wing cutting surface is 69°.

[0010] As a further improvement of the utility model, a plurality of main-row cutting teeth are respectively distributed on the cutting surface of each blade, and a secondary-row cutting teeth are arranged at the rear side of the main-row cutting teeth close to the outer edge of the circumference.

[0011] As a further improvement of the present invention, the main row of cutting teeth are PDC cutting teeth, and the auxiliary row of cutting teeth are alloy teeth.

[0012] As a further improvement of the present invention, the main row of cutting teeth are 1613 flat teeth, and the secondary row of cutting teeth are 1312 bread teeth.

[0013] As a further improvement of the present invention, the cutting angle of the main row of cutting teeth is 16°-19°.

[0014] As a further improvement of the utility model, a water eye is arranged between the inner ends of the first long blade wing, the second long blade wing and the third long blade wing, respectively, a fourth water eye is arranged between the first short blade wing and the second long blade wing, and a fifth water eye is arranged between the second short blade wing and the first long blade wing.

[0015] As a further improvement of the utility model, the angle between the axis of each water hole and the axis of the drill bit is 30-32°.

[0016] As a further improvement of the utility model, the inner wall of each water hole is provided with a shock-resistant pipe, and the inner cavity of each shock-resistant pipe is installed with a pulse nozzle.

[0017] As a further improvement of the utility model, the PDC drill bit includes an upper drill bit body and a lower drill bit body that are embedded in each other, the center holes of the upper drill bit body and the lower drill bit body are coaxial and intersecting, a pulse generator is embedded in the middle of the center hole of the drill bit, and the lower end of the center hole of the drill bit is provided with a diversion area communicated with each water hole.

[0018] Compared with the prior art, the utility model has achieved the following beneficial effects: it is used for efficient exploration and development of deep coalbed methane horizontal wells, improves the construction efficiency of abrasive strata above coal seams, and is suitable for drilling before landing in deep coal seam horizontal wells. The drilling speed is fast, which can reduce the number of trips and drills, and realizes a drill bit from the second opening to drill through complex strata until it reaches the landing point close to the coal seam. The drill bit has a long service life and shortens the drilling cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. The drawings are only provided for reference and explanation, not for limiting the present utility model. Among them:

[0020] Figure 1 This is a schematic diagram of the structure of a downhole drilling tool assembly for landing a coalbed methane well according to the utility model;

[0021] Figure 2 This is a front view of the PDC drill bit in the utility model;

[0022] Figure 3 It is a cross-sectional view of the PDC drill bit in the utility model;

[0023] Figure 4 for Figure 2 Bottom view of

[0024] In the figure: A. PDC drill bit; B. Single-bend screw; C. Check valve; D. Seat key joint; E. Non-magnetic drill collar; F. Stabilizer; G. Ordinary drill collar; H. Weighted drill pipe;

[0025] PDC drill bit: 1. Upper body of drill bit; 2. Lower body of drill bit; 2a. Diversion area; 3. Pulse generator; 3a. Bell mouth; 3b. Water inlet hole of resonance cavity; 3c. Disturbance area of ​​resonance cavity; 3d. Conical reduction area; 3e. Separation area of ​​resonance cavity; 4. Pulse nozzle; 5. Blade; 5a. First long blade; 5b. Second long blade; 5c. Third long blade; 5d. First short blade; 5e. Second short blade; 6. Main row of cutting teeth; 7. Secondary row of cutting teeth; 8. Water eye. DETAILED DESCRIPTION

[0026] In the following description of the utility model, the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not mean that the device must have a specific direction.

[0027] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific figures. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0029] like Figures 1 to 4 As shown, the utility model of the downhole drilling tool assembly for landing a coalbed methane well includes a PDC drill bit A, the upper end of the PDC drill bit A is screwed with a single-bend screw rod B, the bending angle of the single-bend screw rod B is 1.25-3°, which is used for inclination of the drill bit, and converts the hydraulic energy of the drilling fluid into mechanical energy, and transmits the torque to the lower PDC drill bit A. The upper end of the single-bend screw rod B is screwed with a one-way valve C, the upper end of the one-way valve C is screwed with a key joint D, the inner cavity of the key joint D is installed with a directional instrument, the upper end of the key joint D is screwed with a non-magnetic drill collar E, the upper end of the non-magnetic drill collar E is provided with a centralizer F, the upper end of the non-magnetic drill collar E is screwed with an ordinary drill collar G, and the upper end of the ordinary drill collar G is screwed with a weighted drill pipe H.

[0030] Taking Liujiagou in Linxing block as an example, the drill tool assembly from bottom to top is: Φ311.2PDC drill bit + Φ244mm single-bend screw (1.25° bend angle with spiral stabilizer) + φ203mm one-way valve + key joint + Φ203mm non-magnetic drill collar + φ308mm stabilizer + matching joint + Φ165mm non-magnetic drill collar + Φ177.8mm ordinary drill collar*9 pieces + φ127mm heavy drill pipe*36 pieces + φ127mm drill pipe*105 pieces + DS550*411 variable buckle joint + Φ139.7mm drill pipe.

[0031] The PDC drill bit A comprises an upper drill body 1 and a lower drill body 2 which are fitted together. The center holes of the upper drill body 1 and the lower drill body 2 are coaxial and intersecting. A tapered male thread is provided on the upper end of the upper drill body 1, and a lower drill body boss is provided on the upper part of the lower drill body 2. The boss of the lower drill body is embedded in the countersunk hole of the upper drill body 1. A pulse generator 3 is embedded in the center hole of the upper drill body. An outer boss of the pulse generator is provided in the middle section of the pulse generator 3. The upper shoulder of the outer boss of the pulse generator abuts against the lower inner step of the center hole of the upper drill body, and the lower shoulder of the outer boss of the pulse generator abuts against the top of the boss of the lower drill body. The lower part of the pulse generator 3 is inserted into the center hole of the lower drill body, and the lower drill body 2 is welded to the upper drill body 1 after being plugged in.

[0032] The split structure facilitates the installation of the pulse generator 3 and automatically ensures the accurate positioning of the pulse generator 3. The pulse generator 3 is embedded between the drill upper body 1 and the drill lower body 2 to achieve axial positioning and ensure that the pulse generator 3 is coaxial with the drill. When the size of the pulse oscillation cavity needs to be changed, it is only necessary to replace the pulse generator 3 before the drill upper body 1 and the drill lower body 2 are assembled, and there is no need to replace the drill upper body 1 and the drill lower body 2 as a whole, thereby reducing production costs.

[0033] The bottom of the drill lower body 2 is a medium parabolic crown structure, and is provided with five blades 5, including three long blades and two short blades. The inner end of the first long blade wing 5a extends to the drill axis, the inner ends of the second long blade wing 5b and the third long blade wing 5c ​​are close to the drill axis, the phase angle between the cutting surface of the first long blade wing 5a and the cutting surface of the second long blade wing 5b is 125°, the phase angle between the cutting surface of the second long blade wing 5b and the cutting surface of the third long blade wing 5c ​​is 93°, and the phase angle between the cutting surface of the third long blade wing 5c ​​and the cutting surface of the first long blade wing 5a is 142°.

[0034] A first short blade wing 5d is arranged between the first long blade wing 5a and the second long blade wing 5b, and the phase angle between the cutting surface of the first long blade wing 5a and the cutting surface of the first short blade wing 5d is 57°; a second short blade wing 5e is arranged between the third long blade wing 5c ​​and the first long blade wing 5a, and the phase angle between the cutting surface of the third long blade wing 5c ​​and the cutting surface of the second short blade wing 5e is 69°. The five blade wings are arranged asymmetrically, which can not only maintain the balance of cutting force, but also prevent the drill bit from rotating at the bottom of the well and causing premature failure of the drill bit.

[0035] A water hole 8 is arranged between the inner ends of the first long blade wing 5a, the second long blade wing 5b and the third long blade wing 5c, respectively; a fourth water hole 8 is arranged between the first short blade wing 5d and the second long blade wing 5b; and a fifth water hole 8 is arranged between the second short blade wing 5e and the first long blade wing 5a. The angle between the axis of each water hole 8 and the axis of the drill bit is 30-32°. The chip removal grooves between the five water holes and the blades can ensure the chip removal efficiency of the drill bit. The characteristic structure of the five blades and double rows of teeth can maintain both rapid drilling and stability of the directional instrument tool face under the condition of increasing inclination.

[0036] A pulse oscillation cavity is provided along the axis of the pulse generator 3, and the pulse oscillation cavity is provided with a bell mouth 3a, a resonance cavity water inlet hole 3b, a resonance cavity disturbance zone 3c, a conical diameter reduction zone 3d and a resonance cavity separation zone 3e in order from top to bottom, the inner diameter of the resonance cavity disturbance zone 3c is larger than the aperture of the resonance cavity water inlet hole 3b, the upper end of the conical diameter reduction zone 3d is connected to the lower end of the resonance cavity disturbance zone 3c, the upper end of the resonance cavity separation zone 3e is connected to the lower end of the conical diameter reduction zone 3d, and the water outlet at the lower end of the resonance cavity separation zone 3e is connected to the center of the diversion zone 2a. A pulse nozzle 4 is installed in each water eye 8, and the inner end of each water eye is connected to the diversion zone 2a.

[0037] When a jet flows from the water inlet 3b of the resonance cavity to the downstream resonance cavity disturbance zone 3c, the vorticity disturbance within a certain frequency range in the jet is amplified, forming a series of discrete vortex rings in the jet layer. When it reaches the conical inner wall of the conical reduction zone 3d and interacts with it, a pressure oscillation wave is generated in the conical reduction zone 3d. The wave propagates upstream at the speed of sound and induces new vortex pulsation. If the pressure pulsations in the resonance cavity separation zone 3e and the conical reduction zone 3d are in antiphase with each other, a cycle of "vortex disturbance-amplification-generation of new vortex pulsation" will be formed. If this process is repeated continuously, a strong self-excited oscillation pulse jet will be formed.

[0038] A plurality of main row cutting teeth 6 are respectively distributed on the cutting surface of each blade 5, and a secondary row cutting teeth 7 are arranged on the rear side of the main row cutting teeth 6 with a larger turning radius near the outer edge of the circumference. Each main row cutting tooth 6 is a PDC cutting tooth with strong impact resistance and high wear ratio.

[0039] In order to improve the lateral attack force of the drill bit, 1613 flat tooth attack type diameter protection is used to improve the deflection rate of the drill bit. The auxiliary row cutting teeth 7 are alloy teeth, using 1312 bread teeth, with good structural comprehensive performance and stronger attack. The medium and low density teeth are suitable for use in medium hardness formations and are conducive to protecting the 1613 flat teeth on the front side.

[0040] In order to improve the impact resistance of the drill bit, ensure effective penetration into the formation, and increase the mechanical drilling speed in hard formations, the PDC tooth cutting angle is adjusted from 30° to 16°-19°.

[0041] 1613 flat teeth and 1312 bread teeth form a double-row tooth hybrid inlay, which prolongs the service life of the drill bit while maintaining a high mechanical drilling speed. Brazing, assembly welding, steel body drill bit surface welding, UT non-destructive testing and upper body heat treatment are carried out according to the "Manufacturing Process Specifications".

[0042] This drill bit combination is used for efficient exploration and development of deep coalbed methane horizontal wells in the Linxing block and its surrounding areas. During the construction of deep coal seam horizontal wells in the Linxing block, this drill bit combination was able to drill through complex formations from the second opening until it reached a landing point close to the coal seam in complex formations such as the Liujiagou, Shiqianfeng Formation, Upper and Lower Shihe Formations, Shanxi Formation, and Taiyuan Formation.

[0043] The above description is only the preferred feasible embodiment of the utility model, which shows and describes the basic principle, main features and advantages of the utility model, but does not limit the scope of patent protection of the utility model. The technicians in this industry should understand that the utility model is not limited by the above embodiments. In addition to the above embodiments, the utility model can also have other implementation modes without departing from the spirit and scope of the utility model. The utility model will also have various changes and improvements. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the utility model. The scope of protection required by the utility model is defined by the attached claims and their equivalents. The technical features not described in the utility model can be achieved by or using existing technologies, which will not be repeated here.

Claims

1. A downhole drilling tool assembly for landing a coalbed methane well, comprising a PDC drill bit, characterized in that: The upper end of the PDC drill bit is screwed with a single-bend screw, the upper end of the single-bend screw is screwed with a one-way valve, the upper end of the one-way valve is screwed with a key joint, the inner cavity of the key joint is equipped with a directional instrument, the upper end of the key joint is screwed with a non-magnetic drill collar, the upper end of the non-magnetic drill collar is provided with a centralizer, the upper part of the non-magnetic drill collar is screwed with an ordinary drill collar, and the upper part of the ordinary drill collar is screwed with a weighted drill pipe; The crown of the PDC drill bit is provided with five blades, including three long blades and two short blades, the inner end of the first long blade extends to the drill bit axis, and the inner ends of the second long blade and the third long blade are close to the drill bit axis; The first short blade wing is arranged between the first long blade wing and the second long blade wing, and the second short blade wing is arranged between the third long blade wing and the first long blade wing.

2. The downhole drilling tool assembly for landing a coalbed methane well according to claim 1, characterized in that: The phase angle between the first long blade wing cutting surface and the second long blade wing cutting surface is 125°, the phase angle between the second long blade wing cutting surface and the third long blade wing cutting surface is 93°, and the phase angle between the third long blade wing cutting surface and the first long blade wing cutting surface is 142°.

3. The downhole drilling tool assembly for landing a coalbed methane well according to claim 1, characterized in that: The phase angle between the first long blade wing cutting surface and the first short blade wing cutting surface is 57°, and the phase angle between the third long blade wing cutting surface and the second short blade wing cutting surface is 69°.

4. The downhole drilling tool assembly for landing a coalbed methane well according to claim 1, characterized in that: A plurality of main-row cutting teeth are respectively distributed on the cutting surface of each blade, and a secondary-row cutting teeth are arranged at the rear side of the main-row cutting teeth close to the outer edge of the circumference.

5. The downhole drilling tool assembly for landing a coalbed methane well according to claim 4, characterized in that: The main row of cutting teeth are PDC cutting teeth, and the auxiliary row of cutting teeth are alloy teeth.

6. The downhole drilling tool assembly for landing a coalbed methane well according to claim 4, characterized in that: The main row of cutting teeth are 1613 flat teeth, and the secondary row of cutting teeth are 1312 bread teeth.

7. The downhole drilling tool assembly for landing a coalbed methane well according to claim 4, characterized in that: The cutting angle of the main row of cutting teeth is 16°-19°.

8. The downhole drilling tool assembly for landing a coalbed methane well according to claim 1, characterized in that: A water eye is arranged between the inner ends of the first long blade wing, the second long blade wing and the third long blade wing, respectively; a fourth water eye is arranged between the first short blade wing and the second long blade wing; and a fifth water eye is arranged between the second short blade wing and the first long blade wing.

9. The downhole drilling tool assembly for landing a coalbed methane well according to claim 8, characterized in that: The angle between the axis of each water hole and the axis of the drill bit is 30-32°.

10. The downhole drilling tool assembly for landing a coalbed methane well according to claim 8, characterized in that: The inner wall of each water hole is provided with a shock-resistant pipe, and the inner cavity of each shock-resistant pipe is provided with a pulse nozzle.

11. The downhole drilling tool assembly for landing a coalbed methane well according to claim 8, characterized in that: The PDC drill bit comprises an upper drill bit body and a lower drill bit body which are embedded in each other. The center holes of the upper drill bit body and the lower drill bit body are coaxial and interpenetrating. A pulse generator is embedded in the middle of the center hole of the drill bit. The lower end of the center hole of the drill bit is provided with a diversion area which is communicated with each water hole.

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