Induced drilling method for inertia constrained implicated motion and inertial constraint induced drilling device

Abstract

The invention discloses an induced drilling method for inertial constraint implicated motion, which is characterized by comprising a motion step of separating weight on bit and torque. The induced drilling method of inertial constraint implicating motion comprises the following steps: step 1, model selection of induced drilling; step 2, potential energy storage of induced drilling, wherein step 2 includes: I, uniform cutting induced drilling under a steady condition; II, distribution of induced drilling shock wave propagation under a transient condition; III, potential energy release of torsion spring in induced drilling under the transient condition; IV, constrained buffer for induced drilling under transient conditions; and V, potential energy compensation for induced drilling under transient conditions. The invention also discloses an inertia constraint induced drilling device accompanying the PDC bit.

Claims

1. An induced drilling method of inertial constraint implicating motion comprising: selecting a model of induced drilling, the selecting including determining the connection between an inertia gear ring with a planet carrier through a torsion spring; storing potential energy from the induced drilling, wherein the storing includes: performing uniform cutting induced drilling under a steady condition; distributing induced drilling shock wave propagation under a transient condition; releasing potential energy of the torsion spring in induced drilling under the transient condition; dynamically distributing energy of rock breaking penetration according to a constrained buffer for induced drilling under transient conditions; and compensating for potential energy under transient conditions.

2. A induced drilling method for an inertia constrained implicated motion, characterized by comprising: in a first Step, including selection of a model for an induced drilling: a determined model for the induced drilling connecting an inertia gear ring with a planet carrier via a torsion spring; wherein determined parameters of the determined model for the induced drilling are: a transmission ratio m between a drill string input and a drill bit output in a drilling device induced by a inertia constraint of a PDC bit is more than or equal to m≥1.0, and a rotational inertia I of the inertia gear ring is equal to 0.25-5.4 kgm.sup.2; in a second Step, including storage of a potential energy of the induced drilling: starting a drilling system to enable the drill string to start storing potential energy in the torsion spring at a rotation speed ω.sub.0; when a torque of the drill bit reaches a rock breaking torque T.sub.0, the inertia gear ring twists the torsion spring by θ radian relative to the drill bit, and reverse potential energy-mt.sub.0θ is stored in the torsion spring according to a transmission method of a planetary gear reducer with a transmission ratio m; rotating the drill bit, and a stored reverse potential energy is kept in the torsion spring; the stored reverse potential energy exists as a median value of torque fluctuation change, a storage of the potential energy of the induced drilling is realized based on deformation of the torsion spring connected between a planet carrier output shaft of a planet gear reducer and the inertia ring gear; when the planet carrier output shaft and the inertia ring gear rotate relative to each other and the planet carrier output shaft rotates clockwise, the inertia ring gear rotates counterclockwise relative to the planet carrier output shaft, and the torsion spring between the planet carrier output shaft and the inertia ring gear generates elastic deformation, a storage direction of the potential energy of the induced drilling is opposite to a movement direction of the drilling system to form reverse energy storage; a storage stage of the induced drilling potential energy is a stage before the drill bit of the drilling system starts rock breaking; a storage size of the induced drilling potential energy is a median value of fluctuation change in the drilling process; in a third Step, including a steady and transient induced drilling: the steady and transient induced drilling have different working conditions, specifically: I under a uniform cutting induced drilling under a steady condition, cutting and inducing drilling at a constant speed under the steady condition, rotation speeds of a sun gear, the planet carrier and the inertia gear ring of the inertia constraint inducing drilling device are consistent, the stored potential energy has no relative change and remains in the torsion spring, II under distribution of a induced drilling shock wave propagation under a transient condition, during the induced drilling under the transient condition, generating with the drill bit shear wave S with torsional shear stress amplitude τ.sub.0, and the shear wave S propagates upward at the speed of transverse shear wave; the shear wave S propagates to a planet wheel through the planet carrier, according to conservation principle of momentum and kinetic energy and the transmission ratio m, a shear wave stress amplitude distributed to the inertia ring gear is −mτ.sub.0, and a shear wave stress amplitude distributed to the sun gear is τ.sub.0/m; the shear wave stress amplitude distributed to the inertia ring gear −mτ.sub.0 propagates into the torsion spring, causing circumferential wave motion of the inertia ring gear, effectively guiding and absorbing a impact wave motion of the drill bit; however, the stress amplitude τ.sub.0/m distributed to sun gear shear wave continues to upload along the drill string, weakening the disturbance in a drill string movement, thus improving a movement stability of the overall drilling system, III under potential energy release of the torsion spring in induced drilling under the transient condition, releasing an elastic potential energy stored in the torsion spring when the drill bit cutting at constant speed encounters resistance, which is a blocking energy, during drilling; energy released by a inertial constraint induced drilling system naturally matches the blocking energy to adapt to a blocking resistance during drilling; a resistance of the drill bit during drilling means that a rotation speed of the drill bit when stuck is zero or a rotation speed of the drill bit when stuck is reduced; a released energy naturally matches a blocked energy in accordance with energy conservation and momentum conservation laws; IV under constrained buffer for induced drilling under the transient condition, when the drill bit breaks through a resistance point, rotating the drill bit to accelerate the penetration, and dynamically redistributes an energy of the rock penetration of the drill bit; a dynamic redistribution is a momentum equilibrium distribution that changes with a time of encounter; the energy distributed to the inertia ring gear causes the inertia ring gear to return to forward rotation; energy distributed to the drill bit makes the drill bit continue to drill at a constant speed; V under potential energy compensation for induced drilling under the transient condition, sources of potential energy compensation for the induced drilling under the transient condition are: generating a torque energy input by the drill string during the drilling is supplemented to the potential energy of the torsion spring; and a potential energy generated by a relative displacement change between a forward rotation of the inertia gear ring and the uniform drilling motion of the drill bit is input and supplemented into the torsion spring.

3. The induced drilling method according to claim 2, characterized in that under the transient working condition, when the potential energy of the torsion spring in induced drilling is released, when the stuck rotation speed of the drill bit is zero, the inertia gear ring stops rotating under the implication of the torsion spring, so that the inertia kinetic energy Iω.sub.0.sup.2/2 existing in the inertia gear ring is superposed with the stored reverse potential energy −mt.sub.0θ, resulting in the instantaneous reduction of the stored reverse potential energy and the instantaneous reduction of the implicating moment to the drill bit; this part of the reduced stored potential energy is instantly released to the drill bit to form an impact on the resistance point of the drill bit, thus breaking through the resistance work of the sticking point.

4. The induced drilling method according to claim 3, characterized in that a period of which the reduced stored potential energy is instantly released is 10-900 milliseconds.

5. The induced drilling method according to claim 2, characterized in that under the transient working condition, when the potential energy of the torsion spring in induced drilling is released, under the condition that the rotation speed of the drill bit is reduced due to resistance, the inertia gear ring is decelerated to ω.sub.i; the forward inertia kinetic energy I(ω.sub.0.sup.2−ω.sub.i.sup.2)/2 of the inertia ring gear is superposed with the stored reverse potential energy −mT.sub.0θ, thus instantly reducing the inertia ring gear kinetic energy and the stored potential energy; the reduced reverse stored potential energy is instantly released to the drill bit, so that the drill bit has enough torsional energy to overcome the blocking moment.

6. The induced drilling method according to claim 2, characterized in that the inertia constraint is a relatively static inertia motion state constraint generated by the inertia gear ring under the condition of resistance change encountered by the drill bit; in order to form this constraint, the inertia gear ring is connected to the drill bit through a torsion spring, and the drilling system meets the revolution condition; on the basis of satisfying the above conditions, when the drill bit encounters resistance, the shear stress wave s has not yet spread to the inertia ring gear, and the inertia ring gear has not generated corresponding dynamic response, and the rotation inertia of the original revolution speed and direction remains unchanged.

7. The induced drilling method according to claim 2, characterized in that an implied motion refers to a circumferential alternating motion generated by the torsion spring to implicate the inertial ring gear relative to the drill bit under a condition of instantaneous differential mechanical imbalance between the inertial ring gear and the drill bit after encountering resistance.

8. The induced drilling method according to claim 2, characterized in that the induced drilling refers to periodic drilling in which sudden resistance during uniform cutting movement causes changes in bit torque and speed, resulting in instantaneous release of stored energy to break resistance and timely recovery and supplement of potential energy.

9. An inertia constraint induced drilling device accompanying a PDC bit, which is used for performing the induced drilling method of inertia constraint implicated motion according to claim 2, and is characterized in that a separation of a weight on bit and torque can be realized, wherein the weight on bit is transmitted to the bit through the sun gear and the planet carrier, the torque is transmitted to the bit through an inertia double gear ring and the torsion spring, and a structure for separation comprises a sun gear input shaft, the inertia double gear ring, the planet gear, an end face pressure bearing, a planet carrier output shaft, the planet carrier, a pinion shaft, a small sliding bush and a multi-head torsion spring; wherein the planet carrier is sleeved on an outer circumferential surface of the sun gear input shaft, and the small sliding bearing bush is sleeved on a circumferential surface of the sun gear input shaft; four planetary gear shafts are evenly distributed on a surface of the planet carrier; eight planetary gears are all divided into two groups, and the two groups of the eight planetary gears are axially arranged and sleeved on each planetary gear shaft, wherein a first group of planetary gears is close to the input shaft of the sun gear and is connected with a drill collar; an end face of the first group of planetary gears is jointed with a inner end face of one end step of the sun gear input shaft through an end face pressure bearing; an output shaft sleeve of the planet carrier is connected with the outer circumferential surface of the sun gear input shaft, and an inner end surface of the output shaft of the planet carrier is jointed with the outer end surface of the planet carrier; one end of the inertia double gear ring is sleeved on an outer circumferential surface of one end of the sun gear input shaft connected with the drill collar, an other end of the inertia double gear ring is sleeved on an outer circumferential surface of the planet carrier output shaft, and an inner surface of the middle part of the inertia double gear ring is meshed with an outer circumferential surface of the planet gear; a large sliding bearing bush is arranged at an inner periphery of the cavity between an inner surface of the inertia double gear ring and an outer surface of the sun gear input shaft; the multi-head torsion spring is constrained by elastic implication, the multi-head torsion spring is sleeved on an outer circumferential surface of the output shaft of the planet carrier, an inner end surface of the multi-head torsion spring is embedded with an outer end surface of the inertial double gear ring, and an end surface of the outer end of the multi-head torsion spring is fixed with an outer end surface of the output shaft of the planet carrier through a fixing bolt.

10. The inertia constraint induced drilling device as claimed in claim 9, characterized in that the outer circumferential surface of one end of the sun gear input shaft is an equal diameter section, and an outer circumferential surface of the other end of the sun gear input shaft is in a multi-stage step shape, wherein an circumferential surface of the first stage step is used as a mating surface of the first group of planetary gears, a circumferential surface of the second stage step is used as a mounting surface of the end face pressure bearing, a circumferential surface of the third stage step is used as the mounting surface of an inertia duplex gear ring, and a radially protruding boss is arranged on the circumferential surface of the third stage step for axial positioning of the inertia duplex gear ring; an outer diameter of an equal diameter section of the sun gear input shaft is the same as an inner diameter of the planet carrier, and an end surface of the step difference between the equal diameter section of the sun gear input shaft and the first step surface is used as an axial positioning surface of the planet carrier; an outer diameter of the third step is the same as a maximum outer diameter of the planet carrier output shaft.

11. The inertial constraint induced drilling device according to claim 9, wherein pin holes for mounting the planet carrier are uniformly distributed on an end surface of an inner end of the planet carrier output shaft; an inner surface of the outer end of the planet carrier output shaft is used as a threaded surface for connecting drill bits; an inner surface of the inner end of the planet carrier output shaft is an equal diameter section, and an inner diameter of the equal diameter section is the same as an outer diameter of the sun gear input shaft, so that the planet carrier output shaft and the sun gear input shaft are in clearance fit; an inner diameter of an middle section of an inner surface of the planet carrier output shaft is the same as an outer diameter of an assembly nut, so that the planet carrier output shaft is in clearance fit with the assembly nut; a diameter of the outer surface of the middle section of the planet carrier is the smallest, and outer surfaces of the middle section and two ends are all transited by inclined planes, and a matching clearance between an outer surface of the output shaft of the planet carrier and an inner surface of the multi-head torsion spring is formed in an middle section as a deformation space of the multi-head torsion spring; an outer circumferential surface of an inner end of the output shaft of the planet carrier is a stepped surface, which is used for installing the inertial double gear ring; the multi-head torsion spring is sleeved on an outer circumferential surface of the planet carrier output shaft.

12. The inertial constraint induced drilling device according to claim 9, wherein a modulus of the planetary gear is 1.0 to 5.0.

13. The inertial constraint induced drilling device according to claim 9, wherein two groups of straight tooth surfaces meshed with planetary gears are axially arranged on an inner circumferential surface of the inertial double gear ring; a inner circumferential surface of one end of the inertia double gear ring is matched with the stepped surface on an outer circumference of one end of the sun gear input shaft, and an inner circumferential surface of other end of the inertia double gear ring is matched with the stepped surface on an outer circumference of the planet carrier output shaft; grooves are evenly distributed on an end surface of one end of the inertia double gear ring which is matched with output shaft of the planet carrier and are used for fitting connection with end surface of the multi-head torsion spring.

14. The inertial constraint induced drilling device according to claim 9, wherein an assembly nut is installed at a tail end of the sun gear input shaft; the assembly nut is sleeved on the outer circumferential surface of the sun gear input shaft and is positioned between the outer circumferential surface of the sun gear input shaft and an inner circumferential surface of the planet carrier output shaft.

15. The inertial constraint induced drilling device according to claim 9, wherein the planet carrier is a hollow rotary body; mounting holes for planet gears are uniformly distributed on the shell of the planet carrier; four shaft holes for installing output shafts of each planet carrier are uniformly distributed on the end surfaces of two ends of the planet carrier; each shaft hole is respectively communicated with two ends of each rectangular through hole, so that the corresponding through holes respectively positioned on the end surfaces of the two ends of the planet carrier are concentric; an axially protruding annular boss is arranged at an inner edge of the end face of one end of the planet carrier, and the boss is a stop.

16. The inertial constraint induced drilling device according to claim 15, wherein the outer diameter of the planet carrier is smaller than the inner diameter of the inertial double gear ring, and the inner diameter of the planet carrier is 3-8 mm larger than the outer diameter of the sun gear input shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a mechanical model diagram of the induced drilling.

(2) FIG. 2 is a schematic diagram of torsional energy storage for induced drilling.

(3) FIG. 3 is a schematic diagram of uniform cutting in induced drilling.

(4) FIG. 4 is a schematic diagram of shear wave distribution in induced drilling.

(5) FIG. 5 is a schematic diagram of potential energy release of the induced drilling.

(6) FIG. 6 is a schematic diagram of inertial constraint buffer for induced drilling.

(7) FIG. 7 is a schematic diagram of potential energy supplement for induced drilling.

(8) FIG. 8 is a schematic diagram comparing torque speed fluctuation between a drill bit and an induced drilling model; Wherein: FIG. 8a is a schematic diagram of fluctuation torque of a drill bit, FIG. 8b is a schematic diagram of fluctuation rotation speed of the drill bit, FIG. 8c is a schematic diagram of fluctuation torque of a model, and FIG. 8d is a schematic diagram of fluctuation rotation speed of the model.

(9) FIG. 9 is a flowchart of the present invention.

(10) FIGS. 10A and 10B are structural diagrams of an inertial constraint drilling device accompanying a PDC bit, wherein FIG. 10A is a front view and FIG. 10B is a view taken along line A-A of FIG. 1A.

(11) FIGS. 11A and 11B are schematic structural views of the sun gear input shaft, wherein FIG. 11A is a front view and FIG. 11B is a right view.

(12) FIGS. 12A and 12B are schematic structural views of the planet carrier output shaft, wherein FIG. 12A is a left view and FIG. 12B is a front view.

(13) FIGS. 13A, 13B and 13C are schematic structural views of planetary gears, wherein FIG. 13A is a left view. FIG. 13B is a front view, and FIG. 13C is an isometric view.

(14) FIGS. 14A and 14B are schematic structural views of a planetary gear shaft, wherein FIG. 14A is a left view and FIG. 14B is a front view.

(15) FIGS. 15A, 15B and 15C are schematic structural views of an inertial double ring gear, wherein FIG. 15A is a front view, FIG. 15B is a right view, and FIG. 15C is an isometric view.

(16) FIGS. 16A, 16B and 16C are schematic structural views of a planet carrier, wherein FIG. 16A is a front view. FIG. 16B is a right view, and FIG. 16C is an isometric view.

(17) FIGS. 17A and 17B are schematic structural views of a multi-head torsion spring, wherein FIG. 17A is a front view and FIG. 17B is a sectional view of FIG. 17A.

DETAILED DESCRIPTION OF EMBODIMENT(S)

(18) In the various drawings, the same reference numerals represent the same or corresponding elements or components.

(19) Step 1: Model Selection for the Induced Drilling.

(20) The geological structure of oil drilling is granite formation. PDC is used for drilling, 654 m to 760 m is drilled, the diameter of the drilling hole is 8½ inch, the drill bit is 5-blade PDC, and the wellhead is equipped with 20 drilling rigs. After the parameters of the model for the induced drilling are determined, an 8½ inch inertial constraint induced drilling device with PDC bit is used to implement the application case. The specific structural type and design parameters of the determined model refer to “AN INERTIA CONSTRAINT INDUCED DRILLING DEVICE WITH PDC BIT” disclosed in the invention with application number 201710558964.1, wherein the transmission ratio m of drill string input and bit output is m=2.75, the torsional rigidity K.sub.t of torsion spring is 1200 kNm/rad, and the rotational inertia I of inertia ring gear is 1.25 kgm.sup.2.

(21) The inertia constraint induced drilling device accompanying the PDC bit comprises a sun gear input shaft, an inertia double gear ring, planetary gears, an end face pressure bearing, a planet carrier output shaft, a planet carrier, a planet gear shaft, a small sliding bearing bush and a multi-head torsion spring. The planet carrier is sleeved on the outer circumferential surface of the sun gear input shaft, and the small sliding bearing bush is sleeved on the circumferential surface of the sun gear input shaft. The four planetary gear shafts are evenly distributed on the surface of the planet carrier. Eight planetary gears are divided into two groups, and the two groups of planetary gears are sleeved on each planetary gear shaft in an axial arrangement, wherein the first group of planetary gears is close to the end of the drill collar connected with the sun gear input shaft. The end face of the first group of planetary gears is jointed with the inner end face of the step at one end of the sun gear input shaft through an end face pressure bearing.

(22) The output shaft sleeve of the planet carrier is connected with the outer circumferential surface of the input shaft of the sun gear, and the inner end surface of the output shaft of the planet carrier is jointed with the outer end surface of the planet carrier.

(23) One end of the inertia double gear ring is sleeved on the outer circumferential surface of the end of the sun gear input shaft connected with the drill collar, and the other end of the inertia double gear ring is sleeved on the outer circumferential surface of the planet carrier output shaft, and the inner surface of the middle part of the inertia double gear ring is meshed with the outer circumferential surface of the planet gear. A large sliding bearing bush is arranged on the inner periphery of the cavity between the inner surface of the inertia double gear ring and the outer surface of the sun gear input shaft.

(24) The multi-head torsion spring is a multi-head torsion spring constrained by elastic implication, the multi-head torsion spring is sleeved on the outer circumferential surface of the planet carrier output shaft, the inner end surface of the multi-head torsion spring is embedded with the outer end surface of the inertial double gear ring, and the end surface of the outer end of the multi-head torsion spring is fastened to the outer end surface of the planet carrier output shaft through a fixing bolt.

(25) In this embodiment, the planet carrier output shaft at the bottom of the model is butted with 8½ inch PDC bit through API 4-1/2REG thread interface, and the sun gear at the top of the model is butted with drill collar through API NC46 thread interface. PDC bits, matching models and drill collars are led down into the wellbore, and twelve drill collars and several drill pipes are continuously butted up, with the depth of 654 m leading down to the bottom of the well. The drilling height of the wellhead is butted against the square drill stem, and the drilling mud circulation system is connected. The input idle torque of the wellhead rotary table is 270 Nm. The release weight of the hook of the drilling machine is set to 50 KN. The set rotation speed of the rotary table of the drilling machine is ω.sub.0=45 r/min=4.70 rad/s, and mud circulation and drilling are started.

(26) After the drilling torque reaches the cutting rock breaking torque of the drill bit, the drill bit starts to start. At this time, the input torque of the wellhead rotary table has reached 1090 Nm, so the rough calculation of the drill bit torque parameter is T.sub.0=1090 Nm−270 Nm=820 Nm.

(27) Step 2: Storage of the Potential Energy for the Induced Drilling.

(28) Start the drilling system so that the drill string starts to store potential energy in the torsion spring at the rotation speed ω.sub.0. When the torque of the drill bit reaches the rock breaking torque T.sub.0, the inertia gear ring will twist the torsion spring to rotate θ radians relative to the drill bit. According to the transmission method of the planetary gear reducer with the transmission ratio of in, the reverse potential energy stored in the torsion spring is −mT.sub.0θ. The drill bit starts rotating and cutting, and the stored reverse potential energy is retained in the torsion spring. The stored reverse potential energy exists in the whole drilling process as the median of torque fluctuation.

(29) The storage of the induced drilling potential energy is realized based on the deformation of the torsion spring connected between the planet carrier output shaft of the planet gear reducer and the inertia ring gear. When the output shaft of the planet carrier rotates relative to the inertia ring gear, the inertia ring gear rotates counterclockwise relative to the output shaft of the planet carrier during clockwise rotation of the output shaft of the planet carrier. The torsion spring between the output shaft of the planet carrier and the inertia ring gear generates elastic deformation.

(30) The storage direction of the induced drilling potential energy is opposite to the movement direction of the drilling system to form reverse energy storage.

(31) The storage stage of the induced drilling potential energy is the stage before the drill bit of the drilling system starts to break rock.

(32) The storage size of the induced drilling potential energy is the median value of fluctuation during drilling.

(33) According to the invention, when the drill string starts to input torque, since the starting torque of the drill bit has not yet reached the rock breaking torque T.sub.0 of drilling and the drill bit has not yet started, the dynamic model of inertia constraint drag induced drilling is in the static motion condition of the planetary gear reducer fixed with the planet carrier input by the sun gear, and is suitable for calculation of the kinematic model.

(34) As shown in FIG. 2, the rotational speed of the input shaft before starting is ω.sub.0=4.7 rad/s, according to the transmission method of the planetary gear reducer with the transmission ratio m=2.75, the obtained reverse rotation speed of the inertia ring gear is −ω.sub.0/m=−1.71 rad/s. Once the accumulated torque of the drill bit reaches to the drilling rock breaking torque T.sub.0=820 Nm, the induced drilling of the inertia constrained implicative motion starts to enter the drilling cutting state. At this time, the radian angle that the torsion spring has rotated through the inversion implicative of the inertia gear ring is −θ=−t.sub.0/K.sub.t=−0.683 rad, the implicative torsion spring torque mT.sub.0 is 2255 N, and the stored torsion potential energy of the induced torsion spring is −mT.sub.0θ=−1540 J.

(35) Step 3: Steady and Transient Induced Drilling.

(36) I Uniform Speed Cutting Induced Drilling Under the Steady Condition.

(37) After the induction drilling bit is started, if the drilling material is homogeneous and the torque of the bit is stable, the drilling system is balanced and the operation is uniform and stable, and continuous cutting can meet the technical requirements of stable drilling. The inertial constrained induced drilling system has no dynamic response of vibration shock. At this time, the rotational speeds of the sun gear, the planet carrier and the inertia ring gear are the same, there is no relative movement between the transmission element, the inertia element and the energy storage torsion spring, no impact vibration of inertia dynamics occurs, and the stored potential energy exists in the form of internal force.

(38) As shown in FIG. 3, the rotation speeds of the drill string, sun gear, planet carrier, inertia ring gear and drill bit are consistent, all being ω.sub.0=4.70 rad/s, the input torque of the drill string and the output torque of the drill bit are equal to T.sub.0=820 Nm, the torque of the torsion spring is mT.sub.0=2255 N, and the potential energy stored by the torsion spring −mT.sub.0θ=−1540 J, which maintains the initial state of the drill bit starting cutting and has no dynamic response inducing motion.

(39) II Shock Wave Propagation Distribution of the Induced Drilling Under Transient Conditions.

(40) After the start-up of the induced drilling bit, when the bit encounters non-uniform anisotropic material or unstable drilling pressure, the drill bit will inevitably experience circumferential fluctuation. At this time, the induced drilling system constrained by inertia and implicated motion will begin to generate dynamic response of vibration impact.

(41) As shown in FIG. 4, the drill bit moving at a uniform speed and restrained by inertia suddenly encounters resistance, for example, the drill bit suddenly encounters resistance of gravel or anisotropic material during cutting, resulting in the shear wave S with torsional shear stress amplitude to, which propagates upward at the speed of transverse shear wave. The amplitude of torsional shear stress τ.sub.0=70 MPa. First, the shear wave S propagates to the planet wheel through the planet carrier. Secondly, according to the principle of conservation of momentum and kinetic energy and transmission ratio, the amplitudes of shear wave stress distributed by the shear wave S of planetary gear to inertial ring gear and sun gear are −mT.sub.0=−193 MPa and to/m=25 MPa respectively. Finally, the amplified inertia ring gear shear wave −mτ.sub.0=−193 MPa is propagated into the torsion spring to cause inertia-constrained circumferential wave motion, effectively guiding and absorbing the impact wave motion of the drill bit.

(42) However, the weakened sun gear shear wave τ.sub.0/m=25 MPa continues to upload along the drill string, which weakens the disturbance to the overall drilling motion system and improves the stability of the overall drilling system.

(43) In other words, most of the torsional fluctuation amplitude of the drill bit is transmitted to the independently induced inertial ring gear element system, which basically does not affect the drill string motion system with continuous torque input.

(44) III Under transient conditions, induce the release of potential energy of torsion spring during drilling.

(45) The moment when the inertia constraint drag drilling running at uniform speed encounters resistance is also the moment when the energy stored in the structure of this embodiment is released.

(46) As shown in FIG. 5, when the rotation speed of the drill bit is zero due to sticking, the inertia ring gear will be stopped and then reversed, however, the inertia ring gear with the rotation inertia moment of 1=1.25 kgm.sup.2 still has positive inertia kinetic energy Iω.sub.0.sup.2/2=14 J, and its inertia kinetic energy is superposed with the stored reverse potential energy −mT.sub.0θ=−1540 J, which instantly causes the inertia ring gear kinetic energy to disappear into 0, the stored reverse potential energy to instantly reduce to −1526 J, and the reduced reverse potential energy reduces the implicating torque on the drill bit. The reverse potential energy is instantly released to the drill bit to form an impact on the resistance point of the drill bit, so as to obtain resistance work that breaks through the point where the drill bit is stuck.

(47) When the rotation speed of the drill bit is reduced due to resistance, the inertia ring gear will also be induced and decelerated to ωI, the forward inertia kinetic energy I(ω.sub.0.sup.2−ω.sub.i.sup.2)/2<14 J of the inertia ring gear is superposed with the stored reverse potential energy −mT.sub.0θ=−1540 J, thus instantly reducing the kinetic energy of the inertia ring gear and the stored potential energy. The reduced stored potential energy is instantly released to the drill bit, so that the drill bit has enough torsional energy to overcome the blocking torque. According to the conservation theorem of momentum and energy, the magnitude of energy released by the inertial constraint implicating drilling system naturally matches the blocking energy and automatically adapts to the drilling resistance.

(48) The instants described in this embodiment are 10-900 milliseconds.

(49) IV Constrained Buffer for Induced Drilling Under Transient Conditions.

(50) Usually, when the drill bit breaks through the resistance point, the rotation will accelerate and dash forward, thus causing greater impact vibration, resulting in tooth collapse damage of the drill bit. The constraint buffer of the inertia constraint implicating drilling system in this embodiment refers to the working condition that the inertia gear ring stops or reverses under the condition of large resistance moment such as sticking.

(51) As shown in FIG. 6, when the drill bit breaks through the sticking resistance, the breaking resistance energy matched with the drill bit will not disappear. Once the rock breaks, the energy of the drill bit will be released suddenly, making the drill bit have the condition to penetrate into the non-high resistance area. At the moment, the torque of the inertial drilling system is not balanced: the torsion spring reserves energy deficit after releasing potential energy, the torque of the drill bit is too large, and the inertial ring gear is basically in a 0 or reverse ω.sub.j state of deceleration and stop, which determines that the thrust energy of the drill bit needs to be dynamically redistributed. On the one hand, the dynamically redistributed energy is distributed to the inertia gear ring to make it rotate back to the forward direction, and on the other hand, it is distributed to the drill bit to make it continue its drilling movement. The trend of dynamic energy redistribution is to distribute the energy to the inertia ring gear I(ω.sub.j.sup.2−ω.sub.i.sup.2)/2−mT.sub.0θ, and the energy to the drill bit is zero, thus forming the effect of restraining and buffering the drill bit's penetration and avoiding the drill bit's penetration impact.

(52) V Potential Energy Compensation for Induced Drilling Under Transient Conditions.

(53) This embodiment is aimed at that after the drill bit of inertia constrained drag drilling encounters resistance or sticking and the stored energy is released, each moving part is in a relatively differential state. The rotation speed of the bit planet carrier lags behind the input rotation speed of the drill string sun gear. The rotational speed of the inertia ring gear lags behind the rotational speed of the bit planet carrier. In this differential state, the most drastic change is the rotational speed of the inertia ring gear, the more drastic change is the rotational speed of the bit planet carrier, and the basic constant is always the input rotational speed of the drill string sun gear. The stored energy also needs to be replenished in time after it is released, otherwise inertial constraint implicating drilling cannot ensure the continuous drilling movement of the system.

(54) As shown in FIG. 7, the potential energy compensation source of inertia constrained drag drilling in this embodiment is the continuous input of drill string torque. At this time, the rotation speed has not kept up with the bit's resistance. This speed differential between input and output compensates the stored potential energy released by the torsion spring, forming an incremental energy −mT.sub.0Δθ. In addition, there are also parts I(ω.sub.k.sup.2−ω.sub.j.sup.2)/2−mT.sub.0θ recovered by dynamic redistribution after the rock breaking energy is released, which implicates the inertial ring gear back to the forward rotation speed.

(55) The practical application effect of the invention is that the weight on bit is 50 KN, the rotating speed is 45 r/min, and the returned slurry cuttings are uniform gravel. The wellhead drill string is stable and smooth, and the drilling footage speed range is 6.0 to 10.3 m/h. After reaching the preset depth of 705 m in about 6.4 hours, trip out and drill for coring. After coring, continue drilling with a weight on bit of 50 KN, a rotating speed of 45 r/min and a drilling footage speed of 4.2 to 9.5 m/h. The wellhead drill string is stable and smooth. After reaching a depth of 760 m in about 7.2 hours, the drilling process is completed.

(56) Process Parameters of Various Embodiments

(57) TABLE-US-00001 Application parameter Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Diameter of the well 8½ inch 8½ inch 12¼ inch 9½ inch 6½ inch Bottom of the well 654 m 468 m 2842 m 2452 m 4354 m Drilling machine 20 Drilling machine 20 Drilling machine 50 Drilling machine 50 Drilling machine 70 Drilling machine Geology Granite Denatured granite Petrosilex Tuff Andesite Transmission ratio m 2.75 2.75 1.80 2.05 3.05 Torsional rigidity K.sub.t 1200 kNm/rad 1200 kNm/rad 2500 kNm/rad 1500 kNm/rad 800 kNm/rad Inertia I 1.25 kgm.sup.2 1.25 kgm.sup.2 5.54 kgm.sup.2 2.35 kgm.sup.2 0.85 kgm.sup.2 Drilling weight on bit 50 KN 55 KN 80 KN 60 KN 35 KN Rotary speed ω.sub.0 45 r/min 40 r/min 30 r/min 40 r/min 45 r/min Rock breaking torque T.sub.0 820 Nm 1250 Nm 1780 Nm 720 Nm 540 Nm Torsion angle θ −0.683 rad −0.755 rad −1.05 rad −0.623 rad −0.513 rad Stored potential energy −1540 J −2595 J −3364 J −1440 J −1540 J Blocked stress wave 70 MPa 83 MPa 64 MPa 50 MPa 46 MPa Shock wave distribution −193 & 25 MPa −295 & 39 MPa −115 & 34 MPa −101 & 25 MPa −138 & 15 MPa Released energy 14 J or ≤14 J 17 J or ≤17 J 21 J or ≤21 J 12 J or ≤12 J 9 J or ≤9 J Drilling speed 4 to 10 m/H 3 to 6 m/H 5 to 8 m/H 30 to 50 m/H 1.4 to 1.6 m/H Drilling time 13.6 H 4.5 H 6.5 H 0.2 H 3.5 H Total drilling length 98 m 17 m 46 m 8 m 5 m

(58) As shown in FIGS. 10A-17B, this embodiment is an inertia constrained drilling device with PDC bits, which includes a sun gear input shaft 1, an inertia double ring gear 4, a planet gear 5, an end face pressure bearing 3, a planet carrier output shaft 6, a planet gear shaft 7, a small sliding bush 8 and a multi-head torsion spring 12.

(59) The planet carrier 6 is sleeved on the outer circumferential surface of the sun gear input shaft 1. The four planetary gear shafts 7 are evenly distributed on the surface of the planet carrier. The eight planetary gears 5 are divided into two groups, and the two groups of planetary gears are sleeved on each planetary gear shaft in axial arrangement, wherein the first group of planetary gears is close to the input shaft of the sun gear and connected with the drill collar end. The end face of the first group of planetary gears is jointed with the inner end face of one end step of the sun gear input shaft through an end face pressure bearing 3.

(60) The planet carrier output shaft 9 is sleeved on the outer circumferential surface of the sun gear input shaft 1, and the inner end surface of the planet carrier output shaft is jointed with the outer end surface of the planet carrier. The small sliding bearing bush 1 is sleeved on the circumferential surface of the sun gear input shaft 1. The assembly nut 10 is located at the tail end of the sun gear input shaft, sleeved on the outer circumferential surface of the sun gear input shaft, and located between the outer circumferential surface of the sun gear input shaft and the inner circumferential surface of the planet carrier output shaft 9. The end face of the assembly nut and the sun gear input shaft 1 is equipped with an anti-back bolt 11.

(61) One end of the inertia double gear ring 4 is sleeved on the outer circumferential surface of one end of the connecting drill collar of the sun gear input shaft. The other end of the inertia double gear ring is sleeved on the outer circumferential surface of the planet carrier output shaft 9, and the inner surface of the middle part of the inertia double gear ring is meshed with the outer circumferential surface of the planet gear 5. A large sliding bearing bush 2 is arranged at the inner periphery of the cavity between the inner surface of the inertia double gear ring and the outer surface of the sun gear input shaft 1.

(62) The multi-head torsion spring 12 is a multi-head torsion spring constrained by elastic implications. The multi-head torsion spring 12 is sleeved on the outer circumferential surface of the planet carrier output shaft 9, and the inner end surface of the multi-head torsion spring is embedded with the outer end surface of the inertia double ring gear 4. The end surface of the outer end of the multi-head torsion spring is fixed with the end surface of the outer end of the planet carrier output shaft 9 through a fixing bolt 13.

(63) The sun gear input shaft 1 is a hollow shaft. The outer circumferential surface of one end of the sun gear input shaft is of an equal diameter section, and the outer circumferential surface of the other end is of a multi-stage step shape, wherein the circumferential surface of the first stage step is the mating surface of the first group of planetary gears, the circumferential surface of the second stage step is the mounting surface of the end face pressure bearing, the circumferential surface of the third stage step is the mounting surface of the inertial double gear ring 4, and the circumferential surface of the third stage step is provided with radially protruding bosses for axial positioning of the inertial double gear ring. The outer diameter of the equal diameter section of the sun gear input shaft is the same as the inner diameter of the planet carrier 6, so that the end surface of the step difference between the equal diameter section of the sun gear input shaft and the first step surface becomes the axial positioning surface of the planet carrier 6. The outer diameter of the third step is the same as the maximum outer diameter of the planet carrier output shaft 9.

(64) The planet carrier output shaft 9 is a hollow rotary body. Pinholes are evenly distributed on the end surface of the inner end of the planet carrier output shaft for mounting the planet carrier 6. The inner surface of the outer end of the planet carrier output shaft is a threaded surface for connecting the drill bit. The inner surface of the inner end of the planet carrier output shaft is an equal diameter section, and the inner diameter of the equal diameter section is the same as the outer diameter of the sun gear input shaft 1, so that the planet carrier output shaft is in clearance fit with the sun gear input shaft. The inner diameter of the middle section of the inner surface of the planet carrier output shaft 9 is the same as the outer diameter of the assembly nut 10, so that the planet carrier output shaft is in clearance fit with the assembly nut. The diameter of the outer surface of the middle section of the planet carrier is the smallest, and the outer surfaces of the middle section and both ends transition with inclined planes, and a fitting clearance between the outer surface of the planet carrier output shaft and the inner surface of the multi-head torsion spring 12 is formed at the middle section as a deformation space of the multi-head torsion spring. The outer circumferential surface of the inner end of the output shaft of the planet carrier is a stepped surface for installing the inertial double ring gear 4. The multi-head torsion spring is sleeved on the outer circumferential surface of the planet carrier output shaft.

(65) Planetary gear 5 is a standard spur gear. The modulus of planetary gears is 1.0 to 5.0. In this embodiment, the modulus of the planetary gear is 2.0.

(66) The inertia double gear ring 4 is a hollow revolving body. Two groups of straight tooth surfaces meshed with planetary gears are axially arranged on the inner circumferential surface of the inertial double gear ring. The inner circumferential surface of one end of the inertia double gear ring is matched with a stepped surface on the outer circumference of one end of the sun gear input shaft 1. The inner circumferential surface of the other end of the inertia double gear ring is matched with the stepped surface on the outer circumference of the planet carrier output shaft 9. Grooves are uniformly distributed on the end surface of one end of the inertia double gear ring which is matched with the output shaft of the planet carrier and are used for fitting connection with the end surface of the multi-head torsion spring 12.

(67) The planet carrier 6 is a hollow rotating body. Four rectangular through holes are evenly distributed on the shell of the planet carrier, and the rectangular through holes are mounting holes for planet gears. Four shaft holes are evenly distributed on the end faces of the two ends of the planet carrier for installing the output shafts 9 of each planet carrier. Each shaft hole is respectively communicated with the two ends of each rectangular through hole, so that the corresponding through holes respectively positioned on the end surfaces of the two ends of the planet carrier are concentric. An axially protruding annular boss is arranged at the inner edge of one end face of the planet carrier, and the boss is a stop.

(68) The outer diameter of the planet carrier is smaller than the inner diameter of the inertia double ring gear 4, and the inner diameter of the planet carrier is 3-8 mm larger than the outer diameter of the sun gear input shaft 1.

LIST OF REFERENCE NUMBERS

(69) 1 Drill string 2 Thrust bearing 3 Inertia ring gear 4 Planetary wheels 5 Sun gear 6 Torsion spring 7 Planet carrier 8 Small sliding bearing bush 9 Planet carrier output shaft 10 Assembly nut 11 Anti-backing bolt 12 Multi-headed torsion spring 13 Fixing bolt 18 PDC bit 19 Fluctuating torque of the drill bit 20 Fluctuation speed of the drill bit 21 Fluctuation torque of the model 22 Fluctuation speed of the model