ELECTRIC PULSE DRILLING APPARATUS WITH HOLE CLEANING PASSAGES
An electrical pulse cutting device is disclosed that in one non-limiting embodiment includes a pair of electrodes that generate electrical pulses inside an object to disintegrate a section of the object into cuttings, and at least one flow passage in at least one of the electrodes to provide a passage for a fluid under pressure to move the cuttings away from the at least one of the electrodes.
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1. Field of the Disclosure
The disclosure relates generally to drilling of wellbores and particularly to electrical impulse cutting apparatus for drilling such wellbores.
2. Background Art
Wells or wellbores are formed for the production of hydrocarbons (oil and gas) from subsurface formation zones where such hydrocarbons are trapped. A drill bit at a bottom end of a drill string conveyed from a surface location is rotated to cut through the formation rock to form the wellbores. Commonly used drill bits include mechanical cutters that penetrate the rock due to the weight on the bit to disintegrate the rock into small pieces, referred to as the cuttings or rock cuttings. A drilling fluid is supplied to the drill string that discharges at the bottom of the drill bit, which fluid causes the cuttings to flow through an annulus between the drill sting and wellbore to the surface. Electrical impulse cutting devices have been proposed as an alternative to the conventional mechanical drill bits for forming wellbores. An electrical impulse cutting device utilizes electrodes to impart high voltage pulses into the rock to generate heat and pressure inside the rock to disintegrate the rock into cuttings. Some of the cuttings tend to settle between the electrodes as there is inadequate or no fluid velocity underneath the electrodes to move the cuttings away from the electrodes, inhibiting moving of the cuttings by the drilling fluid to the surface. Therefore, it is desirable to provide electrical impulse cutting devices and system that can effectively move the cuttings away from the electrodes to enable the circulating drilling fluid to move the cuttings to the surface.
The disclosure herein provides an electrical impulse cutting apparatus configured to move to move cuttings away from the electrodes for effective hole cleaning during drilling of wellbores.
SUMMARYIn one aspect, an electrical pulse cutting device is disclosed that in one non-limiting embodiment includes a pair of electrodes that generate electrical pulses inside an object to disintegrate a section of the object into cuttings, and at least one flow passage in at least one of the electrodes to provide a passage for a fluid under pressure to move the cuttings away from the at least one of the electrodes.
In another aspect, a method of forming a wellbore is disclosed that in one embodiment includes: conveying a drill string into a wellbore, wherein the drill string includes an electric pulse cutting device at a bottom end of a drilling assembly, wherein the electric pulse cutting device includes a pair of electrodes and wherein at least one electrode includes a fluid flow passage therethrough to allow a fluid under pressure to pass therethrough to move the cuttings away from the at least one of the electrodes; and disintegrating rock at bottom of the wellbore into cuttings by generating electrical pulses via the pair of electrodes within a selected depth of the rock.
Examples of the certain features of an apparatus and methods have been summarized rather broadly in order that the detailed description thereof that follows may be better understood, and in order that the contributions to the art may be appreciated. There are, of course, additional features that will be described hereinafter and which will form the subject of the claims.
For a detailed understanding of the apparatus and methods disclosed herein, reference should be made to the accompanying drawings and the detailed description thereof, wherein like elements are generally given same numerals and wherein:
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The foregoing disclosure is directed to the certain exemplary non-limiting embodiments. Various modifications will be apparent to those skilled in the art. It is intended that all such modifications within the scope of the appended claims be embraced by the foregoing disclosure. The words “comprising” and “comprises” as used in the claims are to be interpreted to mean “including but not limited to”. Also, the abstract is not to be used to limit the scope of the claims.
Claims
1. An electric pulse cutting device, comprising:
- a pair of electrodes that generates electrical pulses inside an object to disintegrate a section of the object into cuttings; and
- at least one flow passage in at least one of the pair of electrodes to provide a passage for a fluid under pressure to move the cuttings away from the least one of the electrodes.
2. The electric pulse cutting device of claim 1, wherein the pair of electrodes are configured to contact the object to pass electrical energy through a selected depth of the object to disintegrate the object.
3. The electric pulse cutting device of claim 1 further comprising a pulse generator that provides electrical energy to the pair of electrodes at a selected frequency.
4. The electric pulse cutting device of claim 2, wherein the frequency is less 500 hertz.
5. The electric pulse cutting device of claim 1, wherein the pair of electrodes includes a ground electrode that is at least partially outside one of an anode electrode and a cathode electrode and wherein the at least one fluid passage runs through the ground electrode.
6. The electric pulse cutting device of claim 5 further comprising at least one fluid passage through the anode electrode.
7. A drilling apparatus for drilling wellbores, comprising:
- an electric pulse cutting device at a bottom end thereof, wherein the electric pulse device includes:
- a ground electrode and an anode electrode for generating electrical pulses inside a rock formation in a wellbore to disintegrate the rock formation into cuttings; and
- at least one fluid flow passage in one of the ground electrode and the anode electrode to provide a passage for a fluid under pressure to move the cuttings away from at least one of the ground electrode and the anode electrode;
8. The drilling apparatus of claim 7 further comprising: a sensor that provides measurements relating to a downhole parameter of interest and a controller that adjusts a parameter relating to an operation of the electric pulse cutting device in response to the downhole parameter of interest.
9. The drilling apparatus of claim 8, wherein the downhole parameter of interest is selected from a group consisting of: rate of penetration of the electric pulse cutting device; vibration relating to the drilling apparatus; whirl relating to the electric pulse cutting device; and stick-slip of the electric pulse cutting device.
10. The drilling apparatus of claim 7, wherein the ground electrode and the anode electrode are configured to contact the rock formation to pass electrical energy through a selected depth of the rock formation to disintegrate the rock formation into cuttings.
11. The drilling apparatus of claim 7 further comprising a pulse generator that provides electrical energy to the anode electrode and the ground electrode at a selected frequency.
12. The drilling apparatus of claim 7, wherein the at least a portion of the ground electrode is at least partially outside a portion of the anode electrode and wherein the at least one fluid flow passage runs through the ground electrode.
13. The drilling apparatus of claim 8, wherein the controller is located at one of: in a drilling assembly carrying the electric pulse bit; and at a surface location; and partially in a drilling assembly carrying the electric pulse bit and partially at a surface location.
14. The drilling apparatus of claim 7 further comprising a logging while drilling tool that determines a parameter of interest relating to formation surrounding the electrical pulse cutting device.
15. A method of drilling a wellbore, the method comprising:
- conveying a drill string into a wellbore that includes an electric pulse cutting device at a bottom end of a drilling assembly, wherein the electric pulse cutting device includes a pair of electrodes and wherein at least one electrode includes a fluid flow passage therethrough to allow a fluid under pressure to pass therethrough to move the cuttings away from the at least one electrodes;
- disintegrating rock at bottom of the wellbore into cuttings by generating electrical pulses via the pair of electrodes inside a selected depth of the rock; and
- passing the fluid under pressure through the at least one fluid passage to move the cuttings away from the at least one of the electrodes during drilling of the wellbore.
16. The method of claim 15 further comprising determining a parameter of interest relating to the drill string during drilling and adjusting a drilling parameter in response to the determined parameter relating to the drill string.
17. The method of claim 16, wherein the parameter of interest relating to the drill string is selected from a group consisting of: vibration; whirl; and stick-slip.
18. The method of claim 16, wherein the drilling parameter is selected from a group consisting of: rate of penetration; weight on the electrical pulse cutting device; fluid flow rate; pulse frequency; temperature; and pressure.
19. The method of claim 15, wherein the pair of electrodes includes a ground electrode that is at least partially outside one of an anode electrode and a cathode electrode.
20. The method of claim 19, wherein the fluid flow passage runs through the ground electrode.
Type: Application
Filed: Jan 20, 2016
Publication Date: Jul 20, 2017
Applicant: BAKER HUGHES INCORPORATED (HOUSTON, TX)
Inventor: JOERG LEHR (CELLE)
Application Number: 15/001,715