Jet flow combined type reducing auger bit and drilling method thereof

Abstract

The invention discloses a jet flow combined type reducing spiral drill bit and a drilling method thereof, belongs to the technical field of combined drill bits, and solves the problems of fast drill bit loss and low energy utilization rate caused by single rock breaking structure and fixed mechanical and hydraulic energy distribution mode of the existing combined drill bit. The invention relates to a double-spiral variable-wing-piece drilling bit, which comprises a drilling bit main body, the drilling bit main body comprises a rotating shaft, the rotating shaft is provided with a double-spiral variable-wing-piece structure, the double-spiral variable-wing-piece structure comprises a structure main body, the structure main body is spirally provided with a plurality of main spiral wing pieces, a plurality of auxiliary spiral wing pieces and a plurality of nozzles used for spraying pulse jet flow, and the drilling bit main body is provided with a sensor assembly. By means of the double-spiral gradually-changing fin structure, eccentric wear caused by uneven loads on a hard rock section can be reduced, rock debris accumulation on a soft rock section is prevented, the drilling speed is increased, and the service life of the drill bit is prolonged. Meanwhile, data are collected in real time through the sensor assembly, mechanical and hydraulic energy distribution is dynamically adjusted through the controller, and energy waste is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite drill bits, in particular to a jet-flow composite variable-diameter spiral drill bit and a drilling method thereof. BACKGROUND

[0002] The existing composite drill bit includes a single spiral wing piece and a nozzle. In oil drilling, geological exploration or mining, the existing drill bit can usually exhibit high mechanical drilling speed and efficiency when drilling in relatively homogeneous and single lithology strata by virtue of its mature design and stable working mode. However, when the existing composite drill bit encounters complex and variable stratum environment, especially the layer section where hard rock and soft rock frequently appear alternately, the existing composite drill bit is prone to eccentric wear due to uneven wing piece load in the hard rock section, and the drilling speed is reduced due to rock debris accumulation in the soft rock section. At the same time, the existing composite drill bit causes energy waste due to the fixed mechanical and hydraulic energy distribution mode. SUMMARY

[0003] In view of the above problems in the prior art, the present application provides a jet-flow composite variable-diameter spiral drill bit and a drilling method thereof, which solves the problems of fast drill bit wear and low energy utilization rate caused by the single rock breaking structure and the fixed mechanical and hydraulic energy distribution mode of the existing composite drill bit.

[0004] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: On the one hand, a jet-flow composite variable-diameter spiral drill bit is provided, which comprises a drill bit main body, the drill bit main body comprising a rotating shaft, the rotating shaft being provided with a double-spiral gradually changing wing piece structure in the shape of a cone, the double-spiral gradually changing wing piece structure comprising a structure main body, the structure main body being provided with a plurality of main spiral wing pieces, a plurality of auxiliary spiral wing pieces and a plurality of nozzles for spraying pulse jet flow in a spiral manner, the plurality of auxiliary spiral wing pieces and the plurality of nozzles being respectively located between the cutting tooth interval gaps of the plurality of main spiral wing pieces; the drill bit main body is provided with a sensor assembly, and the sensor assembly is signal connected with a controller for regulating and controlling the mechanical and hydraulic energy distribution of the drill bit main body.

[0005] In the present scheme, the main spiral wing piece is used to bear the main rock breaking load, the auxiliary spiral wing piece is used as a secondary rock breaking unit, and the nozzle emits pulse jet flow between the main spiral wing piece teeth, so that the double-spiral gradually changing wing piece structure can reduce eccentric wear caused by uneven load in the hard rock section, prevent rock debris accumulation in the soft rock section, improve the drilling speed and prolong the service life of the drill bit. At the same time, the sensor assembly collects data in real time, the controller dynamically adjusts the mechanical and hydraulic energy distribution, realizes on-demand energy supply, and avoids energy waste.

[0006] Further, the height of each main helical wing gradually decreases along the helical extension direction thereof, and the pitch of each auxiliary helical wing gradually increases along the helical extension direction thereof. The gradually decreasing height of the main helical wing enhances the structural strength of the wing at the root of the drill bit, reduces stress concentration and eccentric wear in the hard rock section, and reduces the sliding friction between the main helical wing and the hole wall. The gradually increasing pitch of the auxiliary helical wing expands the rock debris flow channel, effectively preventing rock debris accumulation in the soft rock section.

[0007] Further, the sensor assembly includes a micro-pressure sensor structure and a vibration acceleration sensing structure; the micro-pressure sensor structure includes a first micro-pressure sensor and two second micro-pressure sensors; the first micro-pressure sensor is located in the root blind hole on the main helical wing; the two second micro-pressure sensors are symmetrically arranged on the side surface of the structural body; the vibration acceleration sensing structure includes a first vibration acceleration sensor, a second vibration acceleration sensor and a third vibration acceleration sensor; the first vibration acceleration sensor and the second vibration acceleration sensor are respectively located in the middle and upper parts of the main helical wing and the auxiliary helical wing; the third vibration acceleration sensor is located on the shaft. The first micro-pressure sensor is used to collect pressure fluctuations and pressure changes of the pulsed jet caused by mechanical rock breaking, and the two second micro-pressure sensors are used to monitor the mud pressure and compare with the data of the main monitoring point to eliminate the pressure measurement deviation caused by mud flow. The first vibration acceleration sensor and the second vibration acceleration sensor are respectively located in the high-frequency area of the main helical wing and the auxiliary helical wing which are impacted by rock debris and mechanical impact, which can capture the acceleration peak of the "bounce effect" of the wing, and the third vibration acceleration sensor is used to monitor the torsional vibration and axial vibration transmitted by the drill pipe, and the position of the shaft is less affected by local impact, so that the basic signal of the overall vibration of the drill bit body can be obtained.

[0008] Further, the inclination angle between the axis of each nozzle and the surface of the structural body is 90°. The vertical nozzle design ensures that the pulsed jet directly impacts the rock surface vertically, enhancing the penetration and crushing effect of the jet.

[0009] In another aspect, a drilling method of the jet-combined variable-diameter spiral drill bit is provided, including the steps of: S1, collecting drilling data in real time through the sensor assembly; S2, establishing a linear inversion model of DRI, wherein DRI is the drillability rock index; S3, assigning the mechanical energy ratio according to the DRI value , and setting the distribution ratio of the mechanical and hydraulic energy of the drill bit body as .

[0010] In this scheme, DRI is used to measure the drillability of rock, and the drillability rock index model is established by collecting data in real time, and the mechanical energy ratio is dynamically calculated according to the hardness of the rock and the mechanical and hydraulic energy distribution ratio is set as ). This enables the drill bit body to increase the mechanical energy ratio in hard rock sections and reduce the hydraulic dependence, increase the hydraulic energy ratio in soft rock sections, promote chip removal, dynamically adjust energy distribution, and avoid energy waste.

[0011] Further, the drilling data includes mechanical rock breaking pressure , jet flow pressure , annular mud pressure , axial vibration acceleration , radial vibration acceleration , and torsional vibration acceleration .

[0012] Further, the calculation expression of the DRI linear inversion model is: wherein, and are calibration coefficients, which can be determined by experiments, are easy to implement in drilling equipment, and improve the practicability and popularization of the method; , , are the energy characteristic values of the axial, radial, and torsional vibration of the drill bit body, and the root mean square (RMS) calculation of the sliding window is performed on the vibration acceleration signal to eliminate high-frequency noise and extract effective features; is the sampling frequency, is the window length; is the radius of the cutting tooth of the main helical blade to the center line of the shaft; is the cutting torque of the drill bit body; is a constant term.

[0013] Further, the distribution expression of the mechanical energy ratio is: In this scheme, DRI>80, 40 DRI 80, and DRI<40 correspond to hard rock, alternating layers, and soft rock, respectively. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a structural schematic diagram of a jet flow composite variable-diameter helical drill bit; Figure 2 is a structural schematic diagram of a jet flow composite variable-diameter helical drill bit; Wherein: 1, main spiral wing; 2, auxiliary spiral wing; 3, rotating shaft; 4, nozzle; 51, first micro pressure sensor; 52, second micro pressure sensor; 61, first vibration acceleration sensor; 62, second vibration acceleration sensor; 63, third vibration acceleration sensor. DETAILED DESCRIPTION

[0015] The specific embodiments of the present application are described below to facilitate the understanding of the present application for those skilled in the art, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the present application defined and determined by the appended claims, and all the inventions utilizing the concept of the present application are within the scope of protection.

[0016] Example 1 The present embodiment provides a jet compound variable diameter spiral drill bit, comprising a drill bit body.

[0017] Reference Figure 1 The drill bit body comprises a rotating shaft 3, and a double spiral gradually changing wing structure in the shape of a cone is arranged on the rotating shaft 3. The double spiral gradually changing wing structure comprises a structure body, and a plurality of main spiral wings 1, a plurality of auxiliary spiral wings 2 and a plurality of nozzles 4 for jetting pulsed jet flow are spirally arranged on the structure body. The plurality of auxiliary spiral wings 2 and the plurality of nozzles 4 are respectively located between the inter-tooth gaps of the plurality of main spiral wings 1, and the nozzles 4 emit pulsed jet flow between the teeth of the main spiral wings 1, so that the double spiral gradually changing wing structure can reduce the eccentric wear caused by uneven load in hard rock section, prevent rock debris accumulation in soft rock section, improve the drilling speed and prolong the service life of the drill bit.

[0018] In the present embodiment, the inclination angle between the axis of each nozzle 4 and the surface of the structure body is 90°, which ensures that the jet flow directly acts on the rock surface to be broken in front of the cutting tooth. At the same time, the nozzle 4 converts the continuous jet flow into high-frequency pulsed jet flow, which enhances the breaking efficiency of soft soil through jet flow pressure.

[0019] Specifically, the material of the main spiral wing 1 is high-strength alloy, which is used to bear the main rock breaking load. The height of each main spiral wing 1 gradually decreases along the spiral extension direction, and the height of the main spiral wing 1 gradually decreases, which enhances the structural strength of the wing at the root of the drill bit, reduces the stress concentration and eccentric wear in the hard rock section, and reduces the sliding friction between the main spiral wing 1 and the hole wall.

[0020] Specifically, the auxiliary spiral wing 2 is made of high-toughness steel, which is used as a secondary rock breaking unit. The pitch of each auxiliary spiral wing 2 gradually increases along the spiral extension direction. The gradually increasing pitch of the auxiliary spiral wing 2 expands the rock debris flow channel, effectively preventing the accumulation of rock debris in the soft rock section.

[0021] The drill bit body is provided with a sensor assembly, and the sensor assembly is signal-connected with a controller for regulating and controlling mechanical and hydraulic energy distribution of the drill bit body. The sensor assembly is used to collect data in real time, and the controller controls the jet flow pressure by dynamically controlling the micro valve on the nozzle 4, so as to dynamically adjust the mechanical and hydraulic energy distribution of the drill bit body.

[0022] Specifically, the sensor assembly comprises a micro-pressure sensor structure and a vibration acceleration sensing structure.

[0023] Reference Figure 2 The micro-pressure sensor structure comprises a first micro-pressure sensor 51 and two second micro-pressure sensors 52. The first micro-pressure sensor 51 is located in the root blind hole on the main helical fin 1, and the two second micro-pressure sensors 52 are symmetrically arranged on the side surface of the structural body.

[0024] The vibration acceleration sensing structure comprises a first vibration acceleration sensor 61, a second vibration acceleration sensor 62 and a third vibration acceleration sensor 63. The first vibration acceleration sensor 61 and the second vibration acceleration sensor 62 are respectively located in the middle upper part of the main helical fin 1 and the auxiliary helical fin 2, and the third vibration acceleration sensor 63 is located on the rotating shaft 3. The first vibration acceleration sensor 61 and the second vibration acceleration sensor 62 are respectively located in the high-frequency area of the main helical fin 1 and the auxiliary helical fin 2 which are subjected to rock collision and mechanical impact, so as to capture the acceleration peak value of the “springback effect” of the fin. The third vibration acceleration sensor 63 is used for monitoring the torsional vibration and axial vibration transmitted by the drill rod, and the position of the rotating shaft 3 is less affected by local impact, so as to obtain the basic signal of the overall vibration of the drill bit body.

[0025] Embodiment 2 This embodiment is a further limitation based on embodiment 1, and the purpose is to specifically provide a drilling method of the jet flow composite variable-diameter spiral drill bit. Other parts not mentioned refer to embodiment 1 or the prior art.

[0026] This embodiment provides a drilling method of the jet flow composite variable-diameter spiral drill bit, comprising the following steps: S1, collecting drilling data in real time through the sensor assembly; the drilling data comprises mechanical rock breaking pressure , jet flow pressure , annular mud pressure , axial vibration acceleration , radial vibration acceleration and torsional vibration acceleration .

[0027] Specifically, the root blind hole position of the first micro-pressure sensor 51 can directly contact the rock being cut, mainly capturing low-frequency pressure fluctuation generated by mechanical cutting, and collecting mechanical rock breaking pressure .

[0028] The original signals collected by the two second micro-pressure sensors 52 arranged symmetrically are , wherein ; is the annular mud pressure, The pulse frequency is less than 10 Hz; is the jet pressure, The pulse frequency is 1-10 kHz, focusing on capturing the high-frequency pulse pressure generated by the jet impact; by extracting the high-frequency component through a band-pass filter, the and can be separated.

[0029] The total energy of the jet composite variable-diameter spiral drill bit is provided by the drill bit driving system (mechanical energy) and the hydraulic system (jet energy), satisfying the expression: wherein, is the total energy; is the mechanical rock breaking energy, calculated by ; is the jet energy, obtained by , that is, , is proportional to the symbol, is the flow rate; is the action time. By controlling and , the proportion of mechanical energy can be adjusted.

[0030] S2, a linear inversion model of DRI is established, DRI is a drillability rock index, used to measure the drillability of rock.

[0031] The calculation expression of the DRI linear inversion model is: wherein, and are both calibration coefficients, which can be determined by experiments, easy to implement in drilling equipment, improving the practicability and popularization of the method; , , are the energy eigenvalues of the axial, radial and torsional vibrations of the drill bit body, respectively, through the root mean square (RMS) calculation of the sliding window of the vibration acceleration signal, the high-frequency noise is eliminated and the effective features are extracted; is the sampling frequency, is the window length; is the radius of the main helical blade cutting tooth to the centerline of the rotating shaft; is the cutting torque of the drill bit body; is a constant term.

[0032] S3, according to the DRI value, the mechanical energy ratio is allocated , and the mechanical and hydraulic energy allocation ratio of the drill bit body is set to ).

[0033] The mechanical energy ratio is The allocation expression is: In this embodiment, DRI>80, 40 DRI 80, DRI<40 respectively correspond to hard rock, alternating layer, soft rock.

[0034] In summary, the beneficial effects of the present scheme are: 1. The existing composite drill bit has only a single helical blade and a fixed nozzle, which leads to uneven blade load in hard rock section, causing eccentric wear, and rock debris accumulation in soft rock section, reducing drilling speed. The present scheme uses a double helical progressive blade structure to reduce uneven load in hard rock section, prevent rock debris accumulation in soft rock section, improve drilling speed and prolong drill bit life, and cooperates with the nozzle 4 to achieve efficient rock breaking in all strata.

[0035] 2. The existing drill bit has fixed mechanical and hydraulic energy allocation, resulting in energy waste. By collecting data in real time and establishing a drillability rock index model, and dynamically calculating the mechanical energy ratio according to the rock hardness , and setting the mechanical and hydraulic energy allocation ratio to ). This allows the drill bit body to increase the mechanical energy ratio in hard rock section and reduce the hydraulic dependence, increase the hydraulic energy ratio in soft rock section to promote debris removal, dynamically adjust the energy allocation, and avoid energy waste.

[0036] 3. The fixed nozzle of the existing composite drill bit has limited jet coverage, which easily leads to rock debris accumulation, causing problems such as sticking and hole wall wear. The nozzle 4 of the present scheme converts continuous jet into high-frequency pulse jet, enhances the breaking efficiency of soft soil through jet pressure, and is located between the cutting teeth of the main helical blade 1, so that the main helical blade has a flow guiding effect, achieving dynamic removal of rock debris.

[0037] 4. The average life of the existing composite drill bit is only 50-80 hours due to problems such as blade eccentric wear and fixed nozzle blockage. The present scheme prolongs the life through structural optimization of the helical progressive blade structure and nozzle position.

[0038] Although the specific embodiments of the application have been described in some detail, by way of example and for clarity of understanding, it should be understood that certain characteristics described herein can be used in various combinations and that other embodiments can be utilized without departing from the spirit of the present application. The description is thus to be considered as given by way of example only and is not intended to limit the scope of the application as defined in the appended claims.

Claims

1. A jet composite variable diameter spiral drill bit, characterized in that: The drill bit comprises a main body, the main body comprises a rotating shaft (3), a conical double-helix gradient wing structure is provided on the rotating shaft (3), the double-helix gradient wing structure comprises a structural body, a plurality of main spiral winglets (1), a plurality of auxiliary spiral winglets (2) and a plurality of nozzles (4) for ejecting pulse jets are spirally provided on the structural body, the plurality of auxiliary spiral winglets (2) and the plurality of nozzles (4) are respectively located between the gaps between the cutting teeth of the plurality of main spiral winglets 1; The drill bit body is provided with a sensor assembly, and the sensor assembly is connected to a controller signal for regulating the mechanical and hydraulic energy distribution of the drill bit body.

2. The jet composite variable diameter spiral drill bit according to claim 1, characterized in that: The wing height of each main spiral wing (1) gradually decreases along the spiral extension direction thereof, and the pitch of each auxiliary spiral wing (2) gradually increases along the spiral extension direction thereof.

3. The jet composite variable diameter spiral drill bit according to claim 1, characterized in that: The sensor assembly includes a micro-pressure sensor structure and a vibration acceleration sensor structure; The micro-pressure sensor structure comprises a first micro-pressure sensor (51) and two second micro-pressure sensors (52); the first micro-pressure sensor (51) is located in a root blind hole on the main spiral wing (1); and the two second micro-pressure sensors (52) are symmetrically arranged on the side surfaces of the structural body; The vibration acceleration sensing structure comprises a first vibration acceleration sensor (61), a second vibration acceleration sensor (62) and a third vibration acceleration sensor (63); the first vibration acceleration sensor (61) and the second vibration acceleration sensor (62) are respectively located at the middle and upper parts of the main spiral wing (1) and the auxiliary spiral wing (2); and the third vibration acceleration sensor (63) is located on the rotating shaft (3).

4. The jet composite variable diameter spiral drill bit according to claim 1, characterized in that: The inclination angle between the axis of each nozzle (4) and the surface of the structural body is 90°.

5. The drilling method of the jet composite variable diameter spiral drill bit according to any one of claims 1 to 4, characterized in that: Including steps: S1, real-time collection of drilling data through sensor components; S2. Establish a linear inversion model of DRI, where DRI is the drillability rock index; S3. Allocate mechanical energy proportion according to DRI value and set the distribution ratio of the drill body mechanical and hydraulic energy to ).

6. The drilling method of the jet composite variable diameter spiral drill bit according to claim 5, characterized in that: The drilling data includes mechanical rock breaking pressure , jet pressure , annular mud pressure , axial vibration acceleration , radial vibration acceleration and torsional vibration acceleration .

7. The drilling method of the jet composite variable diameter spiral drill bit according to claim 6, characterized in that: The calculation expression of the DRI linear inversion model is: in, and All are calibration coefficients; 、 、 are the energy characteristic values ​​of the axial, radial and torsional vibrations of the drill body respectively; is the sampling frequency, is the window length; The radius from the main helical blade cutting teeth to the centerline of the shaft; is the cutting torque of the drill body; is a constant term.

8. The drilling method of the jet composite variable diameter spiral drill bit according to claim 7, characterized in that: Mechanical energy ratio The assignment expression is: .

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