Drilling at a resonant frequency
View Patent ↗In one aspect of the invention, a method for drilling a bore hole includes the steps of deploying a drill bit attached to a drill string in a well bore, the drill bit having an axial jack element with a distal end protruding beyond a working face of the drill bit; engaging the distal end of the jack element against the formation such that the formation applies a reaction force on the jack element while the drill string rotates; and applying a force on the jack element that opposes the reaction force such that the jack element vibrates and imposes a resonant frequency into the formation.
1. A method for drilling a bore hole, comprising the steps of:
deploying a drill bit attached to a drill string in a well bore, the drill bit comprising an axial jack element with an asymmetric distal end protruding beyond a working face of the drill bit;
engaging the distal end of the jack element against a formation such that the formation applies a reaction force on the jack element while the drill string rotates; and
applying a force on the jack element that opposes the reaction force such that the jack element vibrates and causes the formation to vibrate and degrade that formation;
wherein the jack element is rotationally isolated from the drill bit.
2. The method of claim 1 , wherein the force is a spring force or a hydraulic force.
3. The method of claim 2 , wherein the spring force is adjusted by a spring mechanism comprising a compression spring, a tension spring, a coil spring, a Belleville spring, a gas spring, a wave spring, or combinations thereof.
4. The method of claim 3 , wherein the spring mechanism comprises at least two springs engaged with the jack element.
5. The method of claim 2 , wherein the spring force applies the force opposing the reactive force on the jack element.
6. The method of claim 2 , wherein a motor or a piston adjusts the spring force on the jack element.
7. The method of claim 2 , wherein the spring force is controlled hydraulically.
8. The method of claim 1 , wherein approximately 15,000 lbs is loaded to the jack element.
9. The method of claim 1 , wherein a sensor proximate the jack element senses downhole vibrations.
10. The method of claim 1 , wherein a stop disposed in the bore of the drill string restricts the oscillations of the jack element.
11. The method of claim 1 , wherein a portion of the jack element is disposed in a wear sleeve comprising a hardness greater than 58 HRc.
12. The method of claim 1 , wherein a portion of a nozzle is disposed around the jack element.
13. The method of claim 1 , wherein the distal end comprises a pointed geometry.
14. The method of claim 1 , wherein the distal end comprises a blunt geometry.
15. The method of claim 1 , wherein the distal end is brazed to a carbide segment.
16. The method of claim 1 , wherein the distal end comprises a material selected from the group consisting of chromium, tungsten, tantalum, niobium, titanium, molybdenum, carbide, natural diamond, polycrystalline diamond, vapor deposited diamond, cubic boron nitride, TiN, AlNi, AlTiNi, TiAlN, CrN/CrC/(Mo, W)S2, TiN/TiCN, AlTiN/MoS2, TiAlN, ZrN, diamond impregnated carbide, diamond impregnated matrix, silicon bounded diamond, and/or combinations thereof.
17. The method of claim 1 , wherein cutting elements disposed on the working face of the drill bit contact the formation at negative or positive rake angles.
18. The method of claim 1 , wherein the drill string comprises a dampening system disposed on the drill string adapted to restrict vibrations from reaching a drill rig.
19. The method of claim 1 , wherein the jack element protrudes out of a recess formed in a working portion of the drill bit.
20. The method of claim 1 , wherein the formation vibrates at a natural or resonant frequency.