WO2019117868A1

WO2019117868A1 - Laser beam shot pattern delivery and drilling methods

Info

Publication number: WO2019117868A1
Application number: PCT/US2017/065816
Authority: WO
Inventors: Brian Faircloth; Jason D. FRAZE; Ryan P. Mckay; Greg BRAECKEL; Ryan J. NORTON; Allen Tracy
Original assignee: Foro Energy, Inc.
Priority date: 2017-12-12
Filing date: 2017-12-12
Publication date: 2019-06-20
Also published as: BR112019027409A2

Abstract

Systems and methods for performing laser operations in boreholes. Systems and methods for providing a plurality of laser beams in a laser beam pattern to create holes in the bottom of a borehole surface in a pattern correspond to the laser beam pattern. Mechanically removing the laser weakened rock that is associated with the laser created holes.

Description

LASER BEAM SHOT PATTERN DELIVERY AND DRILLING METHODS

BACKGROUND OF THE INVENTION

[0001] The present inventions relate to high power laser energy tools, methods and systems.

[0002] As used herein, unless specified otherwise“high power laser energy” means a laser beam having at least about 1 kW (kilowatt) of power.

[0003] As used herein, unless specified otherwise, the term“earth” should be given its broadest possible meaning, and includes, the ground, all natural materials, such as rocks, and artificial materials, such as concrete, that are or may be found in the ground, including without limitation rock layer formations, such as, granite, basalt, sandstone, dolomite, sand, salt, limestone, rhyolite, quartzite and shale rock.

[0004] As used herein, unless specified otherwise, the term“borehole” should be given it broadest possible meaning and includes any opening that is created in a material, a work piece, a surface, the earth, a formation, a structure (e.g., building, protected military installation, nuclear plant, offshore platform, or ship), or in a structure in the ground, that is substantially longer than it is wide, such as a well, a well bore, a well hole, a micro hole, slimhole, a perforation and other terms commonly used or known in the arts to define these types of narrow long passages. Wells would further include exploratory, production, abandoned, reentered, reworked, and injection wells. Although boreholes are generally oriented substantially vertically, they may also be oriented on an angle from vertical, to and including horizontal. As used herein unless expressly provided otherwise, the“bottom” of a borehole, the“bottom surface” of the borehole and similar terms refer to the end of the borehole, i.e., that portion of the borehole furthest along the path of the borehole from the borehole’s opening, the surface of the earth, or the borehole’s beginning. The terms“side” and“wall” of a borehole should to be given their broadest possible meaning and include the

longitudinal surfaces of the borehole, whether or not casing or a liner is present, as such, these terms would include the sides of an open borehole or the sides of the casing that has been positioned within a borehole. Boreholes may be formed in the sea floor, under bodies of water, on land, in ice formations, or in other locations and settings.

[0005] Boreholes are generally formed and advanced by using drilling equipment having a rotating drilling tool, e.g., a bit. For example and in general, when creating a borehole in the earth, a drilling bit is extending to and into the earth and rotated to create a hole in the earth. In general, to perform the drilling operation the bit must be forced against the material to be removed with a sufficient force to exceed the shear strength, compressive strength or combinations thereof, of that material.

[0006] As used herein, unless specified otherwise, the term“advancing” a borehole should be given its broadest possible meaning and includes increasing the length of the borehole. Thus, by advancing a borehole, provided the orientation is not horizontal, e.g., less than 90° the depth of the borehole may also be increased. The true vertical depth (“TVD”) of a borehole is the distance from the top or surface of the borehole to the depth at which the bottom of the borehole is located, measured along a straight vertical line. The measured depth (“MD”) of a borehole is the distance as measured along the actual path of the borehole from the top or surface to the bottom.

As used herein unless specified otherwise the term depth of a borehole will refer to MD. In general, a point of reference may be used for the top of the borehole, such as the rotary table, drill floor, well head or initial opening or surface of the structure in which the borehole is placed.

[0007] As used herein, unless specified otherwise, the terms“ream”, “reaming”, a borehole, or similar such terms, should be given their broadest possible meaning and includes any activity performed on the sides of a borehole, such as, e.g., smoothing, increasing the diameter of the borehole, removing materials from the sides of the borehole, such as e.g., waxes or filter cakes, and under-reaming.

[0008] As used herein, unless specified otherwise, the terms“drill bit”,“bit”, “drilling bit” or similar such terms, should be given their broadest possible meaning and include all tools designed or intended to create a borehole.

[0009] In types of mechanical drilling the state of the art, and the teachings and direction of the art, provide that to advance a borehole great force should be used to push the bit against the bottom of the borehole as the bit is rotated. This force is referred to as weight-on-bit ("WOB"). Typically, tens of thousands of pounds WOB are used to advance a borehole using a mechanical drilling process. Mechanical bits cut rock by applying crushing (compressive) and/or shear stresses created by rotating a cutting surface against the rock and placing a large amount of WOB. For example, the WOB applied to an 8 3/4" PDC bit may be up to 15,000 lbs, and the WOB applied to an 8 3/4" roller cone bit may be up to 60,000 lbs. When mechanical bits are used for drilling hard and ultra-hard rock excessive WOB, rapid bit wear, and long tripping times result in an effective drilling rate that is essentially economically unviable. The effective drilling rate is based upon the total time necessary to complete the borehole and, for example, would include time spent tripping in and out of the borehole, as well as, the time for repairing or replacing damaged and worn bits.

[0010] As used herein, unless specified otherwise "offshore" and "offshore drilling activities" and similar such terms are used in their broadest sense and would include drilling activities on, or in, any body of water, whether fresh or salt water, whether manmade or naturally occurring, such as for example rivers, lakes, canals, inland seas, oceans, seas, bays and gulfs, such as the Gulf of Mexico. As used herein, unless specified otherwise the term "offshore drilling rig" is to be given its broadest possible meaning and would include fixed towers, tenders, platforms, barges, jack-ups, floating platforms, drill ships, dynamically positioned drill ships, semi-submersibles and dynamically positioned semi-submersibles. As used herein, unless specified otherwise the term "seafloor" is to be given its broadest possible meaning and would include any surface of the earth that lies under, or is at the bottom of, any body of water, whether fresh or salt water, whether manmade or naturally occurring. As used herein, unless specified otherwise the terms "well" and "borehole" are to be given their broadest possible meaning and include any hole that is bored or otherwise made into the earth's surface, e.g., the seafloor or sea bed, and would further include exploratory, production, abandoned, reentered, reworked, and injection wells.. [0011] Generally, the term“about” as used herein, unless specified otherwise, is meant to encompass a variance or range of ±10%, the experimental or instrument error associated with obtaining the stated value, and preferably the larger of these.

[0012] As used herein, unless specified otherwise, the terms“at least _” or

“greater than _” means the same thing as“not having lower than _” or“excluding lower than _” or“not having less than _” or“excluding less than _ Thus, the term“at least 10kW” is the same as, and means the same thing as, the terms“not having a power lower than 10kW” or“not having a power less than 10 kW”. Similarly, the term“greater than 10kW” means the same thing as the terms“excluding a power lower than 10 kW” or excluding a power less than 10 kW.”

[0013] This Background of the Invention section is intended to introduce various aspects of the art, which may be associated with embodiments of the present inventions. Thus, the forgoing discussion in this section provides a framework for better understanding the present inventions, and is not to be viewed as an admission of prior art.

SUMMARY

[0014] It is desirable to develop systems and methods that provide for the delivery of high power laser energy to the bottom of a deep borehole to advance that borehole at a cost effective rate, and in particular, to be able to deliver such high power laser energy to drill through rock layer formations including granite, basalt, sandstone, dolomite, sand, salt, limestone, rhyolite, quartzite and shale rock at a cost effective rate. More particularly, it is desirable to develop systems and methods that provide for the ability to deliver such high power laser energy to drill through hard rock layer formations, such as granite and basalt, at a rate that is superior to prior conventional mechanical drilling operations. The present invention, among other things, solves these needs by providing the system, apparatus and methods taught herein.

[0015] A high power laser system having a high power laser in optical communication with a down hole laser tool for providing a laser beam pattern to a surface of a borehole in a formation in the earth, wherein the improvement is: the down hole laser tool for delivering a laser beam pattern to the surface of the borehole, wherein the surface of the borehole is formed by the formation; the laser beam pattern having a plurality of laser beam shots; wherein upon delivery of the laser beam in the laser beam pattern to the surface of the borehole, the laser beam removes material from the formation in a removal pattern that matches the laser beam pattern, thereby leaving a remaining material pattern of remaining formation material that is a negative of the laser beam pattern; and, a mechanical device capable of removing the remaining formation material in the remaining material pattern.

[0016] Moreover, there is provide these systems, methods and apparatus having one or more of the following features: wherein the laser beam pattern is a plurality of linear shots; wherein the laser beam pattern defines a grid pattern of intersecting linear laser beam shots; wherein the laser beam pattern is a plurality of spaced apart shots; wherein the shots have a cross section of from about 0.5 mm to about 3 mm; wherein the majority of the shots in the laser beam pattern are circular and have a diameter of about 0.9 mm to about 3.0 mm; wherein the majority of the shots in the laser beam pattern have a shot spacing of about 5 mm to about 40 mm; wherein the majority of the shots in the laser beam pattern have a shot spacing of about 8 mm to about 25 mm; wherein the shot pattern fills the bottom surface of a borehole and is adjacent a side wall of the borehole; wherein an outer diameter of the laser beam shot pattern is from about 100 mm to about 250 mm; wherein an outer diameter of the laser beam shot pattern is from about 140 mm to about 180 mm; wherein an outer diameter of the laser beam shot pattern is from about 180 mm to about 250 mm; wherein the laser shots fill about 10% to about 50% of the area of the laser beam pattern; wherein the laser shots fill less than about 30% of the area of the laser beam pattern; wherein the laser shots fill less than about 10% of the area of the laser beam pattern; and, wherein the laser shots fill less than about 2% of the area of the laser beam pattern.

[0017] Still further there is provided a high power laser system having a high power laser in optical communication with a high power optical fiber, the high power optical fiber in optical communication with a down hole laser tool for providing a laser beam pattern to a surface of a borehole in a formation in the earth, wherein the improvement is:the down hole laser tool for delivering a laser beam pattern to the surface of the borehole; the laser beam pattern having an outer diameter that

corresponds to a predetermined outer diameter of the borehole and defines a laser beam pattern area, wherein in the laser pattern covers a bottom surface of the borehole, wherein the bottom surface of the borehole is defined by initial formation material; the laser pattern having a plurality of individual laser beam shots, each shot having a shot area, wherein the shot area for each shot is from about 1 .00 mm² to about 30 mm²; and, the laser shots defining a total laser shot area, whereby the total laser shot area is less than about 50% of the laser pattern area.

[0018] Yet additionally, there is provided these systems, methods and apparatus having one or more of the following features: wherein upon delivery of the laser beam in the laser beam pattern to the surface of the borehole, the laser beam removes initial formation material from the formation in a removal pattern that matches the laser beam pattern, leaving a remaining material pattern of remaining formation material that is a negative of the laser beam pattern and that is about 50% or more of the initial formation material; having a mechanical device capable of removing the remaining formation material in the remaining material pattern; wherein the laser shot pattern is stationary and does not rotate; wherein an the area of the laser beam shot pattern is from about 30 mm² to about 320 mm²; wherein the total laser shot area is less than about 10% of the laser pattern area and whereby the remaining formation material is about 90% or more of the initial formation material; wherein the total laser shot area is less than about 5% of the laser pattern area and whereby the remaining formation material is about 95% or more of the initial formation material; wherein the total laser shot area is less than about 2% of the laser pattern area and whereby the remaining formation material is about 98% or more of the initial formation material; wherein the total laser shot area is less than about 1 % of the laser pattern area and whereby the remaining formation material is about 99% or more of the initial formation material; and wherein the laser beam pattern comprise gauge cutting laser beam shots.

[0019] Furthermore there is provided a high power laser system having a high power laser in optical communication with a high power optical fiber, the high power optical fiber in optical communication with a down hole laser tool for providing a laser beam pattern to a surface of a borehole in a formation in the earth, wherein the improvement is: the down hole laser tool having an optics assembly for delivering a laser beam pattern to the surface of the borehole; the laser beam pattern having an outer diameter that corresponds to a predetermined outer diameter of the borehole and defines a laser beam pattern area, wherein in the laser pattern covers a bottom surface of the borehole, wherein the bottom surface of the borehole is defined by initial formation material; the laser pattern having a from 10 to 100 individual laser beam shots, each shot having a shot area, wherein the shot area for each shot is from about 0.8 mm² to about 30 mm²; wherein the laser system is capable of provident from about 2 kW to about 20 kW of power for each shot in the shot pattern; the laser shots defining a total laser shot area, whereby the total laser shot area is less than about 30% of the laser pattern area; wherein upon delivery of the laser beam in the laser beam pattern to the surface of the borehole, the laser beam removes initial formation material from the formation in a removal pattern that matches the laser beam pattern, leaving a remaining material pattern of remaining formation material that is a negative of the laser beam pattern; and, having a mechanical device capable of removing the remaining formation material in the remaining material pattern.

[0020] Still further there is provide a method of removing material from the earth to advance a borehole in the earth using a high power laser system having a high power laser in optical communication with a down hole laser tool for providing a laser beam pattern to a surface of a borehole in a formation in the earth, the method being:

(a) delivering a laser beam pattern to the bottom surface of the borehole; (b) the laser beam pattern comprising a plurality of laser beam shots; (c) the laser beam shots removing material from the formation creating holes in the bottom surface of the borehole and creating laser affected material between the holes; wherein the holes form a removal pattern that matches the laser beam pattern; and, (d) removing the laser effect material by applying a mechanical force; (e) wherein the borehole is advance into the earth.. [0021] There is provided these methods wherein (i) the laser beams are delivered for a duration of about 1 second to about 30 seconds, (ii) the mechanical force is applied while the laser beam is not being delivered; and steps (i) and (ii) are repeated, thereby advancing the borehole.

[0022] There is provided these methods, apparatus and systems having one or more of the following features: wherein the mechanical force is applied from a device selected from the group consisting of a cutter, a scraper, a bit, a roller, a water jet, and a particle jet; wherein the laser beam pattern comprises from 10 to 100 evenly spaced laser beam shots; wherein the shots in the laser beam pattern are the same power; wherein the shots in the laser beam pattern are from about 1 kW to about 15 kW;

wherein the laser beam pattern comprises a plurality of spots; wherein the laser beam pattern comprises kerfing shots; wherein the laser beam pattern comprises unevenly spaced spots; and wherein the laser beam pattern comprises from 10 to 100 evenly spaced laser beam shots and comprises unevenly spaced spots.

[0023] Yet additionally there is provided a method of forming a plurality of holes in the bottom surface of a borehole in the earth using a high power laser system having a high power laser in optical communication with a high power optical fiber, the high power optical fiber in optical communication with a down hole laser tool for providing a laser beam pattern to a surface of a borehole in a formation in the earth, the method including: delivering a laser beam pattern comprising a plurality of laser beams shots to the surface of the borehole; the laser beam pattern having an outer diameter that corresponds to a predetermined outer diameter of the borehole and defines a laser beam pattern area, wherein in the laser pattern covers the bottom surface of the borehole; the laser pattern comprising a plurality of individual laser beam shots, each shot having a shot area, wherein the shot area for each shot is from about 1.00 mm² to about 30 mm²; and, the laser shots defining a total laser shot area, whereby the total laser shot area is less than about 50% of the laser pattern area; whereby the laser beam shots removes borehole material forming a holes in the borehole surface corresponding to the laser beam pattern. [0024] Further there is provided these methods, apparatus and systems having one or more of the following features: wherein laser affected remaining material is formed between the holes, and wherein the remaining laser affected material is mechanically removed; wherein laser affected remaining material is formed between the holes, and wherein after delivery of the laser beams the remaining laser affected material is mechanically removed; wherein the mechanical force is applied from a device selected from the group consisting of a cutter, a scraper, a bit, a roller, a water jet, and a particle jet; wherein the mechanical force applied is perpendicular to the surface of the borehole; wherein the laser shot pattern is stationary and does not rotate; wherein the shots in the laser shot pattern are fixed and do not move with respect to each other; wherein an area of the laser beam shot pattern is from about 30 mm² to about 320 mm²; wherein a total laser shot area is less than about 10% of the laser pattern area and whereby the remaining laser affect material is about 90% or more of the initial formation material; wherein the total laser shot area is less than about 5% of the laser pattern area and whereby the remaining laser affected formation material is about 95% or more of the initial formation material; and, wherein the laser beam pattern comprise gauge cutting laser beam shots.

[0025] In addition there is provided a method of advancing a borehole, using a high power laser system having a high power laser in optical communication with a high power optical fiber, the high power optical fiber in optical communication with a down hole laser tool for providing a laser beam pattern to a surface of a borehole in a formation in the earth, the method including: delivering a laser beam pattern to the bottom surface of the borehole; the laser beam pattern comprising a from 10 to 200 individual laser beam shots, each shot defining an area, wherein the area for each shot is from about 0.8 mm² to about 30 mm²; wherein each shot in the pattern has a power from about 2 kW to about 20 kW; the laser shots defining a total laser shot area, whereby the total laser shot area is less than about 20% of the laser pattern area;

whereby less than 80% of the surface of the borehole is directly contacted by the laser beam; the laser beams removing initial formation material from the formation in a removal pattern forming holes in the bottom surface of the borehole in a pattern that matches the laser beam pattern; and, mechanically removing the material located in the area between the holes in the pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a plan view of an embodiment of a laser beam pattern on the bottom surface of a borehole in accordance with the present inventions.

[0027] FIG. 2 is a cross sectional view of an embodiment of holes from by delivery of the laser beam pattern of FIG. 1 , in accordance with the present inventions.

[0028] FIG. 2A is a cross sectional view of embodiments of the mechanical forces used in conjunction with the laser beam patterns in accordance with the present inventions.

[0029] FIGS. 3A to 3I are plan views of embodiments of a laser beam patterns on the bottom surface of a borehole in accordance with the present inventions.

[0030] FIG. 4 is cross-sectional view of an embodiment of a deployed laser system in accordance with the present inventions.

DESCRIPTION OF THE DRAWINGS AND THE PREFERRED EMBODIMENTS

[0031] In general, embodiments of the present inventions relate to, methods, apparatus and systems for use in laser drilling of a borehole in the earth, and further, relate to equipment, methods and systems for the laser advancing of such boreholes deep into the earth and at highly efficient advancement rates.

[0032] In general, the present inventions relate to methods, apparatus and systems for use in laser drilling of a borehole in the earth, and further, relate to equipment, methods and systems for the laser advancing of such boreholes deep into the earth and at highly efficient advancement rates. These highly efficient advancement rates are obtainable because the present invention utilize unique laser beam patterns and delivery methods and laser mechanical drilling methods.

[0033] In laser mechanical drilling of a borehole into and through the earth, e.g., a formation in the earth, several small laser beams can be used to form small holes in the borehole in a pattern. The small holes can be spaced apart from each other in a predetermined pattern. The laser beam that creates the small holes in the formation has the effect of damaging or wreaking the surround rock (e.g., earth, formation). Thus, even though the laser beam does not directly strike the rock, it has the affect of damaging or weakening it in the area surround the small laser created hole. The laser affected material (e.g., rock, formation, earth) can them be removed by mechanical means, hydraulic means, and combinations and variation of these. These removal means can be for example a hammer bit, a cutter, a scrapper, a drill bit, a rotary bit, a fluid jet, a particle jet, and other known and later developed devices for cutting or removing earth. Substantially, less force is required to remove the laser affected material that would be needed to remove this material prior to being damaged by the laser. The force can be 10%, 20%, 50% and 60% less to remove the laser affected material than to remove the unaffected (prior to laser damage) material.

[0034] In an embodiment the small holes are created in the bottom of the borehole. The laser beams are directed to the bottom surface of the borehole and remove earth from the bottom to create a number of small holes in the bottom of the borehole surface. The laser beams to create the holes can be delivered simultaneously or at different times, e.g., staggered. In an embodiment they are delivered in a predetermined timing sequence, e.g., a particular shot in the laser beam pattern at a particular time.

[0035] The laser beams forming the shots in the laser beam pattern can be the same or different wavelengths. The laser beams can have beam diameters, at the point where they form the laser spot on the surface of the bottom of the borehole that are from about 0.2 mm to about 40 mm in cross section, the cross sections can be from about 0.5 mm to about 2.5 mm, from about 1 mm to about 5 mm, about 1 mm, about 2 mm and about 2.5 mm.

[0036] The spots, (e.g., laser spots, or spots formed by laser beam shots, or shots) that form the laser beam pattern can be circular, elliptical, linear, square, rectangular or other shapes. The spots can be over lapping, partially overlapping, or separated by predetermined distances and spacing. The spots can be staggered or in line. [0037] The laser beam spots each have their own area, the sum of these area provides a total area of the surface of the borehole that is directly contacted by the laser. This area of direct laser contact is substantially smaller than the total area of the surface of the borehole. The area of direct laser contact, e.g., the total laser spot area, can be 50% or more smaller, 60% or more smaller, 80% or more smaller, 90% or more smaller, 95% or more smaller, than the area of the bottom surface of the borehole, or a cross sectional area of the borehole based upon the borehole diameter.

[0038] The laser spots are configured to form a laser beam pattern. In embodiments the laser beam pattern is the same size, the outer ends of the pattern, are about same diameter and shape of the borehole and borehole diameter. In this manner the total spot area can be 50% or more smaller, 60% or more smaller, 80% or more smaller, 90% or more smaller, 95% or more smaller, 99% or more smaller than the area of the laser pattern.

[0039] The laser pattern can have 2, 3, 5, tens, and hundreds of spots, and all numbers within these ranges. In an embodiment the laser beam pattern and the laser beam spots do not rotate with respect to the borehole and the borehole surface.

In embodiments the laser beam spot location is fixed and does not move within the pattern.

[0040] The laser beam spots can have the same or different powers, and can have the same or different wavelengths. The power of the individual spots in a pattern can be 1 kW or greater, 2 kW or greater, 5 kW or greater, 15 kW or greater, 20 kW or greater, from about 2 kW to about 15 kW, from about 1 kW to about 10 kW, as well as greater and lower powers and powers within these ranges.

[0041] Turning to FIG. 1 , there is shown a schematic of a laser shot pattern 1 on the bottom surface 2 of a borehole in the earth 10. The laser shot pattern 1 is made up of a plurality of individual laser shots 3, 4, 5, 6, 7, etc. In this embodiment the laser shot pattern 1 has a periphery, or outer boundary, defined by the outer most shots 20,

21 , 22, 23, etc. that is near or adjacent the borehole side wall 11.

[0042] The shots 20, 21 , 22, 23, etc. that form the outside of the laser pattern are at or near the borehole sidewall 11. These shots form a kerf rings along the outer end of the pattern and adjacent to the side wall 11. In embodiments the power, duration or both of the laser beams forming these shots, can be different from the power and duration of the other shots (the inner shots, e.g., 3) in the pattern to provide a more or less pronounced kerf.

[0043] Turning to FIG. 2, there is shown an enlarged cross section of a portion of the bottom of the borehole of FIG. 1. The delivery of the laser beam pattern 1 , to the bottom surface 2 of the borehole, forms holes (e.g., laser beam holes, small holes) in the bottom surface 2 of the borehole into the earth 10. Thus, for example laser beam shot 5 will form hole 5a, and laser beam shot 4 would form hole 4a. The area 30 between the holes 5a, 4a, is an area of laser affected material. Preferably the spacing between the holes, in conjunction with the power of the laser beam and duration of the laser beam spot, is such that the laser damage extends from one hole to the next, across the entirety of area 30.

[0044] The laser beam spots can be delivered in short durations, or pulses. The pulses can last for 0.5 seconds, 1 second, 5 seconds, 10 seconds, 60 second, as well as all times within these ranges and longer and shorter times. The pulse or laser beam duration for forming each hole can be the same or different in the laser beam pattern.

[0045] Turning to FIG. 2A there is shown a cross section schematic of the mechanical forces that are applied to remove the laser affected material 50. The mechanical removal means 60 (which can be cutters, pin point probes, drill bits, water jets, particle jets, combinations of these, etc.) engages the surface 2 of the borehole and applies force to the remaining material 50, e.g., the laser effect material 30. The force can be applied in a manner that is perpendicular to the borehole surface 2, or at an angle to the borehole surface 2.

[0046] Turning to FIGS. 3A to 3I there are shown embodiments of laser shot patterns, having laser shots, placed on the bottom surface of borehole. In FIG. 3A there is shown a laser shot pattern 301 a, having laser shots 302a in a staggered pattern where all shots in the pattern maintain even spacing, within a borehole having a side wall 303a. In FIG. 3B there is shown a laser shot pattern 301 b, having laser shots 302a that are parallel spaced lines where all shots in the pattern maintain even spacing and the pattern does not extend to the borehole wall 303b, within the borehole. In FIG. 3C there is shown a laser shot pattern 301c, having laser shots 302c in a grid pattern that extends to the borehole sidewall 303c, within a borehole. In FIG. 3D there is shown a laser shot pattern 301 d, having laser shots 302d in a series of concentric coaxial circular rings, within a borehole having a side wall 303d. In FIG. 3E there is shown a laser shot pattern 301 e, having linear laser shots 302e and arcuate kerfing shots 304e, within a borehole having a side wall 303a. In FIG. 3F there is shown a laser shot pattern 301 f, having laser shots 302a that are elliptical and in a staggered pattern, within a borehole having a side wall 303a. In FIG. 3G there is shown a laser shot pattern 301 g, having laser shots 302g in a random central pattern surround by arcuate kerfing shots 304g, within a borehole having a sidewall 303g. In FIG. 3h there is shown a laser shot pattern 301 h, having laser shots 302h in pattern of concentric circular rings, within a borehole having a sidewall 303h. In FIG. 3I there is shown a laser shot pattern 301 i, having laser shots 302i in a pattern of disconnected arcuate rings, within a borehole having a sidewall 303i. .

[0047] In an embodiment the laser beam pattern is a line of shots that form circular spots on the bottom surface of the borehole. The laser shots and circular spots have a diameter from about 0.4 mm to about 4.5 mm, about 0.9 mm to about 2.5 mm and about 1.5 mm to about 2 mm. During drilling the laser beam pattern is rotated around the bottom surface of the borehole. In this manner the laser beam creates a series of arcuate holes that form a removal pattern of concentric rings, leaving a pattern of remaining borehole surface and the formation material that forms the borehole bottom surface, which remaining material is in between and adjacent the rings and forms a pattern that is a negative of the laser beam delivery pattern. If the laser beams are pulsed the rings will be a series of disconnected arcuate rings as shown in FIG. 3I.

If the laser beams are continuous the rings will be circular holes as shown in FIG. 3H. Combinations of pulsed and continuous are contemplated, thus for example a continuous circular hole can be located at or closest to the borehole sidewall, and the disconnected arcuate rings are located inside of the outer circular ring. The spacing between the rings can be uniform, it can be staggered; and it can be staggered so that the shot paths, (e.g., the circular holes) do not coincide with a cutter path. In this manner the bottom surface of the borehole has two discrete areas, one area that is directly contacted by the laser beam, the“laser removal area”; and another that is directly contacted by the mechanical removal device (e.g., cutters, water jets, etc.), the “mechanical removal area”. In preferred embodiment the laser beam does not directly contact the mechanical removal area; and the cutters do not directly contact the laser removal area.

[0048] Thus, in general, and by way of example, there is provided in FIG. 4 a high efficiency laser drilling system 1000 for creating a borehole 1001 in the earth 1002. As used herein the term“earth” should be given its broadest possible meaning, including without limitation rock layer formations, such as, granite, basalt, sandstone, dolomite, sand, salt, limestone, rhyolite, quartzite and shale rock.

[0049] FIG. 4 provides a cut away perspective view showing the surface of the earth 1030 and a cut away of the earth below the surface 1002. In general and by way of example, there is provided a source of electrical power 1003, which provides electrical power by cables 1004 and 1005 to a laser 1006 and a chiller 1007 for the laser 1006. The laser provides a laser beam, i.e. , laser energy, that can be conveyed by a laser beam transmission means 1008 to a spool of coiled tubing 1009. A source of fluid 1010 is provided. The fluid is conveyed by fluid conveyance means 1011 to the spool of coiled tubing 1009.

[0050] The spool of coiled tubing 1009 is rotated to advance and retract the coiled tubing 1012. Thus, the laser beam transmission means 1008 and the fluid conveyance means 1011 are attached to the spool of coiled tubing 1009 by means of rotating coupling means 1013. The coiled tubing 1012 contains a means to transmit the laser beam along the entire length of the coiled tubing, i.e.,“long distance high power laser beam transmission means,” to the bottom hole assembly, 1014. The coiled tubing 1012 also contains a means to convey the fluid along the entire length of the coiled tubing 1012 to the bottom hole assembly 1014. [0051] Additionally, there is provided a support structure 1015, which holds an injector 1016, to facilitate movement of the coiled tubing 1012 in the borehole 1001. Further other support structures may be employed for example such structures could be derrick, crane, mast, tripod, or other similar type of structure or hybrid and combinations of these. As the borehole is advance to greater depths from the surface 1030, the use of a diverter 1017, a blow out preventer (BOP) 1018, and a fluid and/or cutting handling system 1019 may become necessary. The coiled tubing 1012 is passed from the injector 1016 through the diverter 1017, the BOP 1018, a wellhead 1020 and into the borehole 1001.

[0052] The fluid, which can be water, brine, drilling mud, or gas, is conveyed to the bottom 1021 of the borehole 1001. At that point the fluid exits at or near the bottom hole assembly 1014 and is used, among other things, to carry the cuttings, which are created from advancing a borehole, back up and out of the borehole. Thus, the diverter 1017 directs the fluid as it returns carrying the cuttings to the fluid and/or cuttings handling system 1019 through connector 1022. This handling system 1019 is intended to prevent waste products from escaping into the environment and separates and cleans waste products and either vents the cleaned fluid to the air, if permissible environmentally and economically, as would be the case if the fluid was nitrogen, or returns the cleaned fluid to the source of fluid 1010, or otherwise contains the used fluid for later treatment and/or disposal.

[0053] The BOP 1018 serves to provide multiple levels of emergency shut off and/or containment of the borehole should a high-pressure event occur in the borehole, such as a potential blow-out of the well. The BOP is affixed to the wellhead 1020. The wellhead in turn may be attached to casing. For the purposes of simplification the structural components of a borehole such as casing, hangers, and cement are not shown. It is understood that these components may be used and will vary based upon the depth, type, and geology of the borehole, as well as, other factors.

[0054] The downhole end 1023 of the coiled tubing 1012 is connected to the bottom hole assembly 1014. The bottom hole assembly 1014 contains optics for delivering the laser beam 1024 in a laser beam pattern having a plurality of laser beam shots to its intended target, in the case of FIG. 1 , the bottom 1021 of the borehole 1001. The bottom hole assembly 1014, for example, also contains means for delivering the fluid.

[0055] Thus, in general this system operates to create and/or advance a borehole by having the laser create laser energy in the form of a laser beam. The laser beam is then transmitted from the laser through the spool and into the coiled tubing. At which point, the laser beam is then transmitted to the bottom hole assembly where it is directed toward the surfaces of the earth and/or borehole as a plurality from about 10 to 50 to 100 to more, of individual laser shots that form a laser beam delivery pattern on, e.g., the bottom of the surface of the borehole. Upon contacting the surface of the earth and/or borehole the laser beam spots have sufficient power (from about 2 kW to about 20 kW or more) to cut, or otherwise effect, the rock and earth creating areas of laser removed material, that mirrors the laser beam pattern and an area of the earth that remains in a pattern that is the mirror image of the laser beam pattern, the remaining material is also weekend by the thermal and other effects of the laser beam spots.

[0056] The remaining material can them be removed by a mechanical device, requiring significantly less force then would be needed to remove unaffected material, i.e. , the material before it was weakened by the laser. In a preferred embodiment the laser weakened material, the formation or the earth, is not directly contacted with the laser beam. Thus, in embodiments the remaining formation material has not been struck, and preferably not struck directly by the laser beam or the laser beam pattern. The weakened material is then mechanically removed by for example a cutter, hammer, bit, a probe, or drill bit. Fluid jets, and particle jets, may also be used in conjunction with mechanical cutting devices. The laser beam at the point of contact has sufficient power and is directed to the rock and earth in such a manner that it is capable of borehole creation that is comparable to or superior to a conventional mechanical drilling operation. Depending upon the type of earth and rock and the properties of the laser beam this cutting occurs through spalling, thermal dissociation, melting, vaporization and combinations of these phenomena. [0057] The fluid then carries the cuttings up and out of the borehole. As the borehole is advanced the coiled tubing is unspooled and lowered further into the borehole. In this way the appropriate distance between the bottom hole assembly and the bottom of the borehole can be maintained. If the bottom hole assembly needs to be removed from the borehole, for example to case the well, the spool is wound up, resulting in the coiled tubing being pulled from the borehole. Additionally, the laser beam may be directed by the bottom hole assembly or other laser directing tool that is placed down the borehole to perform operations such as perforating, controlled perforating, cutting of casing, and removal of plugs. This system may be mounted on readily mobile trailers or trucks, because its size and weight are substantially less than conventional mechanical rigs.

[0058] In addition to coiled tubing drill strings may be used, a wire line and down hole tractor may be used, as well as other conveyance systems known in the art.

[0059] In an embodiment, the lasers are located down hole, at or near, or as a part of the laser bottom hole assembly. In this manner the laser beam(s) that from the laser beam spots can be generated down hole. Down hole lasers and laser beam generation is taught and disclosed in US Patent Publication No. 2016/0084008, the entire disclosure of which is incorporated herein by reference.

[0060] Embodiments of laser drilling systems, laser down hole assemblies, optical assemblies and other laser drilling systems are components are disclosed and taught in US Patent Nos. 8,511 ,401 , 8,826,973, 9,244,235, 9,074,422, 8,571 ,368, 9,027,668, and 8,661 ,160, the entire disclosures of each of which are incorporated herein by reference.

[0061] The laser can generate laser beams from about greater than about 1 kW, greater than about 5 kW, greater than about 20 kW, greater than about 40 kW, from about 20 kW to about 40 kW, from about 1 kW to about 80 kW or more. The laser beams that from each laser beam spot can be from about 1 kW, about 2 kW, about 5 kW, about 10 kW, about 15 kW, about 20 kW, from about 1 kW to about 20 kW, and greater. [0062] The laser beam can have a wavelength from about 400 nm to about 1 ,550 nm, about 400 nm to about 600 nm, less than about 800 nm, from about 450 nm to about 900 nm, about 400 to about 500 nm, about 500 nm to about 600 nm, about 600 nm to about 700 nm, and about 900 nm to about 1 ,200 nm, high and lower wavelengths may also be used.

[0063] The present systems, may include one or more optical manipulators.

An optical manipulator may generally control a laser beam, such as by directing or positioning the laser beam to spall material, such as rock. In some configurations, an optical manipulator may strategically guide a laser beam to spall material, such as rock. For example, spatial distance from a borehole wall or rock may be controlled, as well as the impact angle. In some configurations, one or more steerable optical manipulators may control the direction and spatial width of the one or more laser beams by one or more reflective mirrors or crystal reflectors. In other configurations, the optical manipulator can be steered by an electro-optic switch, electroactive polymers, galvonometers, piezoelectrics, and/or rotary/linear motors. In at least one configuration, a diode laser or fiber laser optical head may generally rotate about a vertical axis to increase aperture contact length. Various programmable values such as specific energy, specific power, pulse rate, duration and the like maybe implemented as a function of time. Thus, where to apply energy may be strategically determined, programmed and executed so as to enhance a rate of penetration and/or laser/rock interaction, to enhance the overall efficiency of borehole advancement, and to enhance the overall efficiency of borehole completion, including reducing the number of steps on the critical path for borehole completion. One or more algorithms may be used to control the optical manipulator.

[0064] In general, embodiments of the down hole assembly, laser bottom hole assembly (LBHA) or bottom hole assembly (BHA) which terms are to be used

interchangeable, unless specifically provided otherwise, may contain an outer housing that is capable of withstanding the conditions of a downhole environment and optics for the shaping and directing a laser beam on the desired surfaces of the borehole, casing, or formation. The assembly may further contain or be associated with a system for delivering and directing fluid to the desired location in the borehole, a system for reducing or controlling or managing debris in the laser beam path to the material surface, a means to control or manage the temperature of the optics, a means to control or manage the pressure surrounding the optics, and other components of the assembly, and monitoring and measuring equipment and apparatus, as well as, other types of downhole equipment that are used in conventional mechanical drilling operations.

[0065] The LBHA and optics, in at least one aspect, can provide that a beam spot pattern and continuous beam shape may be formed by a refractive, reflective, diffractive or transmissive grating optical element. Refractive, reflective, diffractive or transmissive grating optical elements may be made, but are not limited to being made, of fused silica, quartz, ZnSe, Si, GaAs, YAG, polished metal, sapphire, and/or diamond. These may be, but are not limited to being, optically coated with the said materials to reduce or enhance the reflectivity.

[0066] In accordance with one or more aspects, one or more refractive lenses, diffractive elements, transmissive gratings, and/or reflective lenses may be added to focus, scan, and/or change the beam spot pattern from the beam spots emitting from the fiber optics that are positioned in a pattern. One or more refractive lenses, diffractive elements, transmissive gratings, and/or reflective lenses may be added to focus, scan, and/or change the one or more continuous beam shapes from the light emitted from the beam shaping optics. A collimator may be positioned after the beam spot shaper lens in the transversing optical path plane. The collimator may be an aspheric lens, spherical lens system composed of a convex lens, thick convex lens, negative meniscus, and bi-convex lens, gradient refractive lens with an aspheric profile and achromatic doublets. The collimator may be made of the said materials, fused silica, ZnSe, SF glass, YAG, or a related material. The collimator may be coated to reduce or enhance reflectivity or transmission. Said optical elements may be cooled by a purging liquid or gas.

[0067] In some aspects, the fiber optics and said one or more optical elements lenses and beam shaping optics may be encased in a protective optical head made of, for example, the materials steel, chrome-moly steel, steel cladded with hard-face materials such as an alloy of chromium-nickel-cobalt, titanium, tungsten carbide, diamond, sapphire, or other suitable materials known to those in the art which may have a transmissive window cut out to emit the light through the optical head.

[0068] In accordance with one or more aspects, a laser source may be coupled to a plurality of optical fiber bundles with the distal end of the fiber arranged to combine fibers together to form bundle pairs, such that the power density through one fiber bundle pair is within the removal zone, e.g., spallation or vaporization zone, and one or more beam spots illuminate the material, such as rock with the bundle pairs arranged in a pattern to remove or displace the rock formation.

[0069] In accordance with one or more aspects, the pattern of the bundle pairs may be spaced in such a way that the light from the fiber bundle pairs emerge in one or more beam spot patterns that comprise the geometry of a rectangular grid, a circle, a hexagon, a cross, a star, a bowtie, a triangle, multiple lines in an array, multiple lines spaced a distance apart non-linearly, an ellipse, two or more lines at an angle, or a related shape. The pattern of the bundle pairs may be spaced in such a way that the light from the fiber bundles emerge as one or more continuous beam shapes that comprise above geometries. A collimator may be positioned at a said distance in the same plane below the distal end of the fiber bundle pairs. One or more beam shaping optics may be positioned at a distance in the same plane below the distal end of the fiber bundle pairs. An optical element such as a non-axis-symmetric lens may be positioned at a said distance in the same plane below the distal end of the fiber bundle pairs. Said optical elements may be positioned at an angle to the rock formation and rotated on an axis. The optical fibers may be single-mode and/or multimode. The optical fiber bundles may be composed of single-mode and/or multimode fibers. It is readily understood in the art that the terms lens and optic(al) elements, as used herein is used in its broadest terms and thus may also refer to any optical elements with power, such as reflective, transmissive or refractive elements. In some aspects, the optical fibers may be entirely constructed of glass, hollow core photonic crystals, and/or solid core photonic crystals. The optical fibers may be jacketed with materials such as, polyimide, polyamide, acrylate, carbon polyamide, or carbon/dual acrylate. Light may be sourced from a diode laser, disk laser, chemical laser, fiber laser, or fiber optic source is focused by one or more positive refractive lenses.

[0070] In at least one aspect, the positive refractive lens types may include, a non-axis-symmetric optic such as a plano-convex lens, a biconvex lens, a positive meniscus lens, or a gradient refractive index lens with a plano-convex gradient profile, a biconvex gradient profile, or positive meniscus gradient profile to focus one or more beams spots to the rock formation. A positive refractive lens may be comprised of the materials, fused silica, sapphire, ZnSe, YAG, or diamond . Said refractive lens optical elements can be steered in the light propagating plane to increase/decrease the focal length. The light output from the fiber optic source may originate from a plurality of one or more optical fiber bundle pairs forming a beam shape or beam spot pattern and propagating the light to the one or more positive refractive lenses.

[0071] In some aspects, the refractive positive lens may be a microlens. The microlens can be steered in the light propagating plane to increase/decrease the focal length as well as perpendicular to the light propagating plane to translate the beam. The microlens may receive incident light to focus to multiple foci from one or more optical fibers, optical fiber bundle pairs, fiber lasers, diode lasers; and receive and send light from one or more collimators, positive refractive lenses, negative refractive lenses, one or more mirrors, diffractive and reflective optical beam expanders, and prisms. In at least one aspect, the positive refractive lens may focus the multiple beam spots to multiple foci, to remove or displace the rock formation.

[0072] The apparatus and methods of the present invention may be used with drilling rigs and equipment such as in exploration and field development

activities. Thus, they may be used with, by way of example and without limitation, land based rigs, mobile land based rigs, fixed tower rigs, barge rigs, drill ships, jack-up platforms, and semi-submersible rigs. They may be used in operations for advancing the well bore, finishing the well bore and workover activities. They may further be used in any application where the delivery of the laser beam to a location, apparatus or component that is located in a well bore and more preferably deep in the well bore may be beneficial or useful. [0073] The various embodiments of systems, equipment, techniques, methods, activities and operations set forth in this specification may be used for various other activities and in other fields in addition to those set forth herein. Additionally, these embodiments, for example, may be used with: other equipment or activities that may be developed in the future; and with existing equipment or activities which may be modified, in-part, based on the teachings of this specification. Further, the various embodiments set forth in this specification may be used with each other in different and various combinations. Thus, for example, the configurations provided in the various embodiments of this specification may be used with each other; and the scope of protection afforded the present inventions should not be limited to a particular embodiment, configuration or arrangement that is set forth in a particular embodiment, example, or in an embodiment in a particular Figure.

[0074] The invention may be embodied in other forms than those specifically disclosed herein without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.

Claims

What is claimed:

1. A method of removing material from the earth to advance a borehole in the earth using a high power laser system having a high power laser in optical communication with a down hole laser tool for providing a laser beam pattern to a surface of a borehole in a formation in the earth, the method comprising:

a. delivering a laser beam pattern to the bottom surface of the borehole; b. the laser beam pattern comprising a plurality of laser beam shots; c. the laser beam shots removing material from the formation creating holes in the bottom surface of the borehole and creating laser affected material between the holes; wherein the holes form a removal pattern that matches the laser beam pattern; and,

d. removing the laser effect material by applying a mechanical force;

e. wherein the borehole is advance into the earth..

2. The method of claim claim 1 , wherein (i) the laser beams are delivered for a

duration of about 1 second to about 30 seconds, (ii) the mechanical force is applied while the laser beam is not being delivered; and steps (i) and (ii) are repeated, thereby advancing the borehole.

3. The method of claim 1 , wherein the mechanical force is applied from a device

selected from the group consisting of a cutter, a scraper, a bit, a roller, a water jet, and a particle jet.

4. The methods of claims 1 , 2, and 3, wherein the laser beam pattern comprises from 10 to 100 evenly spaced laser beam shots.

5. The methods of claims 1 , 2, and 3, wherein the shots in the laser beam pattern are the same power.

6. The methods of claims 1 , 2 and 3, wherein the shots in the laser beam pattern are from about 1 kW to about 15 kW.

7. The method of claims 1 , 2 and 3, wherein the laser beam pattern comprises a plurality of spots.

8. The methods of claims 1 , 2, and 3, wherein the laser beam pattern comprises

kerfing shots.

9. The methods of claims 1 , 2 and 3, wherein the laser beam pattern comprises

unevenly spaced spots.

10. The methods of claims 1 , 2, and 3, wherein the laser beam pattern comprises from 10 to 100 evenly spaced laser beam shots and comprises unevenly spaced spots.

11. A method of forming a plurality of holes in the bottom surface of a borehole in the earth using a high power laser system having a high power laser in optical communication with a high power optical fiber, the high power optical fiber in optical communication with a down hole laser tool for providing a laser beam pattern to a surface of a borehole in a formation in the earth, the method comprising:

a. delivering a laser beam pattern comprising a plurality of laser beams shots to the surface of the borehole;

b. the laser beam pattern having an outer diameter that corresponds to a predetermined outer diameter of the borehole and defines a laser beam pattern area, wherein in the laser pattern covers the bottom surface of the borehole;

c. the laser pattern comprising a plurality of individual laser beam shots, each shot having a shot area, wherein the shot area for each shot is from about 1.00 mm² to about 30 mm²; and,

d. the laser shots defining a total laser shot area, whereby the total laser shot area is less than about 50% of the laser pattern area;

e. whereby the laser beam shots removes borehole material forming a holes in the borehole surface corresponding to the laser beam pattern.

12. The method of claim 11 , wherein the holes are arcuate lines and wherein laser affected remaining material is formed between the holes, and wherein the remaining laser affected material is mechanically removed.

13. The method of claim 12, wherein the holes are a plurality of arcuate rings.

14. The methods of claims 12 and 13 wherein the mechanical force is applied from a device selected from the group consisting of a cutter, a scraper, a bit, a roller, a water jet, and a particle jet.

15. The methods of claims 12 and 13, wherein the mechanical force applied is

perpendicular to the surface of the borehole.

16. The method of claims 11 , wherein the laser shot pattern is stationary and does not rotate.

17. The method of claims 11 , 12, and 13 wherein the shots in the laser shot pattern are fixed and do not move with respect to each other.

18. The method of claim 11 , wherein an area of the laser beam shot pattern is from about 30 mm² to about 320 mm².

19. The method of claim 18, wherein a total laser shot area is less than about 10% of the laser pattern area and whereby the remaining laser affect material is about 90% or more of the initial formation material.

20. The method of claims, 11 , 12, and 13, wherein the total laser shot area is less than about 5% of the laser pattern area and whereby the remaining laser affected formation material is about 95% or more of the initial formation material.

21. The high power laser systems of claim 1 and 11 , wherein the laser beam pattern comprise gauge cutting laser beam shots.

22. A method of advancing a borehole, using a high power laser system having a high power laser in optical communication with a high power optical fiber, the high power optical fiber in optical communication with a down hole laser tool for providing a laser beam pattern to a surface of a borehole in a formation in the earth, the method comprising:

a. delivering a laser beam pattern to the bottom surface of the borehole; b. the laser beam pattern comprising a from 5 to 200 individual laser beam shots, each shot defining an area, wherein the area for each shot is from about 0.8 mm² to about 30 mm²; wherein each shot in the pattern has a power from about 2 kW to about 20 kW;

c. the laser shots defining a total laser shot area, whereby the total laser shot area is less than about 20% of the laser pattern area; whereby less than 80% of the surface of the borehole is directly contacted by the laser beam; d. the laser beams removing initial formation material from the formation in a removal pattern forming holes in the bottom surface of the borehole in a pattern that matches the laser beam pattern leaving bottom surface material in the area between the holes; and,

e. mechanically removing the material located in the area between the holes in the pattern.