# Patent

## Title
Long distance high power optical laser fiber break detection and continuity monitoring systems and methods

## Abstract

A monitoring and detection system for use on high power laser systems, long distance high power laser systems and tools for performing high power laser operations. In particular, the monitoring and detection systems provide break detection and continuity protection for performing high power laser operations on, and in, remote and difficult to access locations.

## Background
This application: (i) claims, under 35 U.S.C. §119(e)(1) the benefit of the filing date of Feb. 24, 2011 of provisional application Ser. No. 61/446,047; (ii) claims, under 35 U.S.C. §119(e)(1) the benefit of the filing date of Feb. 24, 2011 of provisional application Ser. No. 61/446,412; (iii) claims, under 35 U.S.C. §119(e)(1) the benefit of the filing date of Feb. 24, 2011 of provisional application Ser. No. 61/446,312; and (iv) is a continuation-in-part of U.S. patent application Ser. No. 12/544,136 (issued as 8,511,401) filed Aug. 19, 2009, which claims under 35 U.S.C. §119(e)(1) the benefit of the filing date of Feb. 17, 2009 of U.S. provisional application Ser. No. 61/153,271, the benefit of the filing date of Oct. 17, 2008 of U.S. provisional application Ser. No. 61/106,472, the benefit of the filing date of Oct. 3, 2008 of U.S. provisional application Ser. No. 61/102,730, and the benefit of the filing date of Aug. 20, 2008 of U.S. provisional application Ser. No. 61/090,384, the entire disclosure of each of which are incorporated herein by reference.


This invention was made with Government support under Award DE-AR0000044 awarded by the Office of ARPA-E U.S. Department of Energy. The Government has certain rights in this invention.


BACKGROUND OF THE INVENTION
Field of the Invention
The present inventions relate to methods and systems for detecting breaks, damage, interruptions, degradations or unacceptable conditions in high power laser optical fibers used in transmitting high power laser energy over great distances.
As used herein, unless specified otherwise “high power laser energy” means a laser beam having at least about 1 kW (kilowatt) of power. As used herein, unless specified otherwise “great distances” means at least about 500 m (meter). As used herein the term “substantial loss of power,” “substantial power loss” and similar such phrases, mean a loss of power of more than about 3.0 dB/km (decibel/kilometer) for a selected wavelength. As used herein the term “substantial power transmission” means at least about 50% transmittance.
SUMMARY
In the use of high power laser tools, and in particular high power laser tools for applications and processes in remote locations, there is a need for methods and systems for detecting and monitoring conditions of the optical fibers and the efficacy of laser energy transmission, breaks, damage or unacceptable conditions in the high power optical fibers, system and tools used in those applications and processes. The present inventions, among other things, solve these and other needs by providing the articles of manufacture, devices and processes taught herein.
There is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path.
Further, there is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path, in which the operational beam path is at least about 5,000 feet long.
Further, there is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path, in which the operational beam path is at least about 5,000 feet long.
Additionally, there is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path, in which the monitoring and detecting means has a leak detector associated with a fusion splice.
Moreover, there is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path, in which the monitoring and detecting means has a plurality of light detecting devices, associated with a monitoring fiber, wherein the monitoring fiber is associated with an ODTR, whereby the light transmitted a light detecting device is analyzed and correlated to a condition along the operation beam path.
Yet additionally, there is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path, in which the monitoring and detecting means has a plurality of light detecting devices distributed along a portion of a length of the operational beam path, associated with a monitoring fiber, wherein the monitoring fiber is associated with a monitoring device, whereby the light transmitted a light detecting device is analyzed and correlated to a condition along the operation beam path.
Still further, there is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path, in which the detected and analyzed light comprises high power laser back reflections.
Furthermore there is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path, in which the monitoring and detecting means comprises a plurality of light detecting devices and a photodiode.
Moreover, there is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path, in which the monitoring and detecting means has a distributed temperature sensing fiber with sequential bragg gratings for monitoring temperatures along the operational beam path and detecting anomalies in the temperatures.
Yet still further, there is provided a high power laser drilling system for use in association with a drilling rig, drilling platform, drilling derrick, a snubbing platform, or coiled tubing drilling rig for advancing a borehole in hard rock, the system having: a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power; a laser bottom hole assembly; the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; and, a means for monitoring and detecting adverse conditions in the transmission of the high power laser energy along the operational beam path, in which the monitoring and detecting means has a fiber having gratings sequentially positioned along a length of the fiber, wherein the gratings are configured to collect light and transmit the collected light to a monitoring device, whereby a anomaly is capable of being detected prior to a failure.
Additionally, there is provided a monitoring an detection system for monitoring an operational high power laser beam path associated with a high power laser drilling, workover and completion system, the monitoring and detection system having: a monitoring fiber having a length associated with a high power laser fiber having a length; the monitoring fiber having a plurality of light detection devices position along the length of the monitoring fiber and the high power laser fiber; and, the monitoring fiber in optical association with the a monitoring device; whereby light from the high power optical fiber is transmitted through the monitoring fiber and to the monitoring device, wherein the light is correlated to a condition of the operational high power laser beam path.
Still further, there is provided a system for providing high power laser energy to the bottom of deep boreholes, the system having: a source or high powered laser energy capable of providing a high power laser beam; a means for transmitting the laser beam from the high power laser to the bottom of a deep borehole; and, a means for monitoring and detecting adverse optical conditions in the transmission of the high power laser energy.
Yet still additionally, there is provided a method of monitoring and detecting conditions in the transmission of a high power laser beam having a power of greater than about 10 kW, in a high power laser system having an operational beam path, by sampling light from along a plurality of locations along the operation beam path and analyzing the sampled light to determine a condition of the operation beam path.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of an embodiment of a monitoring and detection systems in accordance with the present invention.
FIG. 2 is a schematic of an embodiment of a monitoring and detection systems in accordance with the present invention.
FIG. 3 is a schematic of an embodiment of a monitoring and detection systems in accordance with the present invention.
FIG. 4 is a schematic of an embodiment of a monitoring and detection systems in accordance with the present invention.
FIG. 5 is a schematic of an embodiment of a monitoring and detection systems in accordance with the present invention.
FIG. 6 is a schematic of an embodiment of a monitoring and detection systems in accordance with the present invention.



DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present inventions relate to systems and methods for monitoring fiber continuity and the efficacy of high power laser transmission through long distance fibers, such as by monitoring and detecting various conditions of the fiber, for example: breaks in the fiber, damage to the fiber, losses of continuity in the fiber, or unacceptable conditions that adversely affect the fibers ability to transmit high power laser energy over long distances without substantial power losses. In particular, the present inventions relate to such detection and monitoring systems for use with high power laser tools and systems for performing activities, such as, for example: ROV (remote operated vehicles) operations, laser-pig operations, subsea exploration, subsea activities, nuclear plant related activities, mining and the recovery of natural resources, drilling, workover, completion, cleaning, milling, perforating, monitoring, analyzing, cutting, welding, MWD (measuring while drilling), LWD (Logging while drilling), MWD/LWD, exploration and production of oil, natural gas and geothermal energy, assembling components, and other applications where the ability to provide high power laser energy to distant, remote and/or difficult to access locations may be beneficial.
In general, the present high power laser optical fiber monitoring and detection systems and methods address long distance high power laser energy transmission issues, over the entire optical path of the laser beam from the laser source to the laser tool, work piece or area where the high power laser operation is to take place, which path may be referred to as the “operational beam path”. Thus, the present systems and methods can monitor and detect continuity issues and adverse optical conditions in optical fibers, optical cables, optical conveyance devices, fiber splices, optical connectors, optical couplers and any other optical component along the operational beam path.
The present detection means provide the ability to detect adverse fiber conditions, such as the degradation and/or failure of high power optical fibers, or other continuity issues that may occur along the operational beam path, in fibers having great lengths, e.g., as long as about 1,000 ft, as long as about 5,000 ft, as long as about 10,000 ft, as long as about 20,000 ft, as long as about 30,000 ft and greater and in operational beam paths having lengths as long as about 1,000 ft, as long as about 5,000 ft, as long as about 10,000 ft, as long as about 20,000 ft, as long as about 30,000 if and greater. It is noted that an operation beam path may have one, two, three, or several high power optical fibers, serially optically associated, e.g., by a fusion splice, parallel and combinations of both.
These adverse conditions, typically may occur in situations where the operational beam path is great, and thus, the fiber is deployed over great distances for providing high power laser energy to a remote location to perform a high power laser activity at that remote location, e.g., the end of the operational beam path. In such situations, where the distal end of these fibers are in remote and/or difficult to access locations, it may be difficult, if not impossible to directly observe or see if laser energy is being propagated from the fiber distal end, or if sufficient laser energy is being provided at that end. In general, as used herein the term “proximal end” of an optical fiber will refer to the end that is closest to the high power laser source when the fiber is in optical communication with the laser source, i.e., the end that is receiving the laser beam from the laser source. In general as used herein the term “distal end” of the optical fiber will refer to the end that is optically furthest away from the laser source when the fiber is in optical communication with the laser source.
The following examples are illustrative embodiments of the present inventions, are representative of the types of system and methods of the present inventions, and do not limit the scope of protection to be afforded the present inventions. Additionally, in a monitoring and detection system for a high power laser delivery system, combinations and variations of the embodiments of the following examples may be utilized. To the extent that monitoring fibers optics are employed they may be any type of optical fiber, that meets the environment conditions of deployment, for example, they may be telecommunication type fiber having a diameter of about 20 to about 250 μm.
EXAMPLE 1
In this embodiment a separate monitoring optical fiber is used, which is placed in close proximity to the high power optical fiber, along the length of the operational beam path, a portion of that path, the length of the high power optical fiber, or a portion of the length of the high power fiber. In this manner if the high power fiber is broken, or if high power laser energy escapes along the operational path, the high power laser energy and/or heat will quickly break the monitoring fiber at, or near, the location where the high power fiber break occurred or the high power laser energy escaped.
A monitoring optical signal is transmitted from the proximal end of the monitoring fiber to the distal end. At the distal end, and also preferably along the length of the monitoring fiber, optical devices maybe positioned. The optical devices cause backwards, i.e., in a distal to proximal direction, traveling signals to be returned to the proximal end, where they can be detected, analyzed and integrated into a laser system control network. An optical time-domain reflectometer (OTDR), a spectrometer, or an OTDR with a spectrometer may be used by way of example for the propagation and monitoring of the monitoring signal(s).
The backward reflection optical devices may be mirrors, gratings, and similar type devices. It also may be the end of the fiber, or components further distal to the end of the fiber providing a backwards propagating signal. Further, these devices can reflect the signal with no change, can vary or change the wavelength of the backwards signal, can modulate the signal of the backward reflection, or can otherwise alter that signal for the sake of providing a unique indication of, or signature for, the backward reflection device. Further, optical signals utilized with monitoring fibers may be in the mW ranges, μW ranges, W ranges and 100 W ranges. The power of this signal will depend upon the type of system utilized and other factors.
Thus, in an illustrative implementation of this embodiment, which is illustrated in FIG. 1, several backwards reflection devices 203a, 203b, 203c, 203d are optically associated with the monitoring fiber 201 at 100 foot intervals, with each device having a unique signature for its respective backward signal. In this manner as the unique backwards signals are monitored, the presence and/or absence of specific signals will detect a break in the high power fiber 205, which is contained in a protective outer member 207, e.g., a metal tube, and also provide the general location for the break of the high power fiber 205.
Further, multiple types of optical signals may be sent down the monitoring fiber, multiple and varied types of backward reflection devices may be used, multiple monitoring fibers may be used, and combinations and variations of these may be distributed along a portion of, and/or the entire length of a high power fiber and/or the operational beam path.
Additionally, a looped monitoring fiber may be employed. In this manner a signal would be sent down the monitoring fiber and the return of that signal, as opposed to backward reflected signals, would be monitored. Further, the loop may be placed for example around the outside of a protective shielding for the fiber, for example a metal tube. In this manner if the metal tube was breached by high power laser light the looped monitoring fiber would be broken and the signal disrupted. This type of system could be used in conjunction with monitoring fiber placed inside of the metal tube.
EXAMPLE 2
In this embodiment, a separate monitoring optical fiber is used, which is placed in optical proximity to the high power optical fiber, along the length of the operational beam path, a portion of that path, the length of the high power optical fiber, or a portion of the length of the high power fiber. In this manner light that is “leaked” from the high power fiber during operation can be received by the monitoring fiber. A change in this received light would indicate an event occurring along the operational beam path, and depending upon the nature of the change, may indicate a fiber break.
Either at the distal end of the monitoring fiber, or along its length, light emitted, e.g., leaking, from the sides of the high power optical fiber is received into the monitoring fiber and transmitted to the proximal end of the monitoring fiber where it can be detected, analyzed and integrated into a laser system control network. An OTDR, a spectrometer, or an OTDR with a spectrometer may be used by way of example for monitoring this signal. Additionally, specific changes in intensity and/or wavelength, or other characteristic, of the leaked light can be correlated to various optical events.
Additionally, the leaked light may be directly monitored by an electro-optical sensing device such a diode. In this case the diode detects the leaked light and transmits a signal based upon that light, which signal is then monitored and analyzed.
An illustrative illustration of this embodiment is provided in FIG. 2. Thus, there is a high power optical fiber 215 in a protective outer member 217. Within the protective outer member 217 and adjacent to the high power optical fiber 215 are two monitoring fibers 211, 213, which are associated with a collecting means 202, 204 to direct leaked light from the high power fiber 215 into the respective monitoring fibers 211, 213.
Further, multiple and varied types of optical devices or connections may be used to receive the leaked light, multiple monitoring fibers may be used, and combinations and variations of these may be distributed along a portion of, and/or the entire length of a high power fiber and/or the operational beam path.
EXAMPLE 3
In this embodiment, a separate monitoring optical fiber is used, which is placed in optical proximity to a fiber splice or specific optical components, such as an OSR (optical slip ring), that are in, or part of, the operational beam path. In this manner light that is “leaked” from the splice and/or device during operation can be received by the monitoring fiber. A change in this received light would indicate an invent occurring along the operational beam path, more particularly an event occurring in the splice or component, and depending upon the nature of the change, may indicate a fiber break, or that the component, for example is going out of optical alignment.
Either at the distal end of the monitoring fiber, or along its length, light emitted, e.g., leaking, from the splice or component is received into the monitoring fiber and transmitted to the proximal end of the monitoring fiber where it can be detected, analyzed and integrated into a laser system control network. An OTDR and an OTDR with a spectrometer may be used by way of example for monitoring this signal. Additionally, specific changes in intensity and/or wavelength, or other characteristic, of the leaked light can be correlated to various optical events.
Additionally, the leaked light may be directly monitored by an opto-electrical sensing device, such a photo diode. In this case the diode detects the leaked light and transmits a signal based upon that light, which signal is then monitored and analyzed.
Turning to the embodiment of FIG. 3, there is provided a high power optical fiber 301 that is connected by way of fusion splice 305 to a high power optical fiber optically associated with an OSR 307. A monitoring fiber 303 is optically associated with splice 305. Within the OSR there is provided a photo-diode 306 that measures and/or detects reflections and/or leaked light, the diode has signal wire 304 leading to a monitoring device. A high power optical fiber 308 exits the OSR 307.
Further, multiple and varied types of optical devices or connections may be used to receive the leaked light, or to detect the light, multiple monitoring fibers may be used, and combinations and variations of these may be distributed along a portion of, and/or the entire length of a high power fiber and/or the operational beam path.
EXAMPLE 4
In this embodiment a cladding stripper device is used to intentionally remove light from the cladding of the high power optical cable. Such removal, may be done by way of a mode stripper, or other device. The removed light is then received by a monitoring fiber or an opto-electrical sensing device, such a photodiode. The signals and light from the monitored fiber are then analyzed. Thus, turning to the embodiment of FIG. 4, there is provided a section of a high power optical fiber 410 have a break detection and monitoring means associated with that section. The high power optical fiber has a core 407 surrounded by a cladding 405 (FIG. 4 is a cross-sectional schematic view). In optical association with the outer side of the cladding 405 is a cladding light stripper means 403, for example a mode stripper, a roughened surface of the cladding, an index matched material to the cladding index, or a material having a high index than the cladding index. In this manner, the cladding light stripper 403 strips light from the cladding and conveys it to monitoring fiber 401, where the presence, type, nature, amount of like stripped from the cladding may be analyzed and correlated to a condition along the operation beam path; and an appropriate action taken, such as for example, an emergency stop or shutting down the laser.
Further, multiple and varied types of optical devices or connections may be used to receive the leaked light, or to detect the light, multiple monitoring fibers may be used, and combinations and variations of these may be distributed along a portion of, and/or the entire length of a high power fiber and/or the operational beam path.
EXAMPLE 5
In this embodiment, separate monitoring fibers, or external opto-electrical detection devices are not required. A monitoring optical signal is sent from the proximal end of the high power laser fiber down the cladding and backward reflections of this signal would be created at specific points along the high power fiber. The creation of the backward reflection, may be by gratings in the cladding, or other similar means. This embodiment is preferably employed in double- or multi-clad high power fibers. The location of the backward reflection devices, their signatures and the monitoring of the backward reflections for this embodiment are along the lines of Example 1.
EXAMPLE 6
In this embodiment, separate monitoring fibers, or external opto-electrical detection devices are not required. In this embodiment back reflections that occur during the normal operation of the high power laser system are monitored and changes in those back reflections correlated to optical events, such as a fiber break.
EXAMPLE 7
In this embodiment, separate monitoring fibers, or external opto-electrical detection devices are not required. A monitoring optical signal is sent from the proximal end of the high power laser fiber down the core of the fiber monitored for either a reflection (break) or no reflection (no break) of the fiber. Further, if done at different wavelengths that do not adversely affect the transmission of the high power laser beam, backward reflections of the monitoring signal could be created at specific points along the high power fiber. The creation of the backward reflection, may be by gratings in the cladding, or other similar means. The location of the backward reflection devices, their signatures and the monitoring of the backward reflections for this embodiment are along the lines of Example 1.
In this embodiment a monitoring signal(s) can be sent along with the high power laser transmission down a single fiber, provided that they are all different wavelengths, using gratings or di-chroics to combine the beams at the surface, or proximal end of the high power fiber, and then similar optical devices can be used to separate out the different wavelengths at the distal end, or work area, e.g., down hole. The high power wavelength may be used for high power laser activities, such as drilling etc. The lower power wavelength may be used for monitoring activities, communications and/or diagnostics.
EXAMPLE 8
In this embodiment, separate monitoring fibers, or external opto-electrical detection devices may or may not be used. As the laser energy is directed to a work piece or surface by a high power laser tool, some of the laser energy will be reflected and additionally, light will be emitted from the surface as it is heated by the laser energy. The wavelength of the emitted light, the ratio of reflected to emitted light, the ratio of reflected to delivered light, and other properties of the light present at the work surface, may be analyzed, to determine fiber continuity and well as overall operation of the laser tool and the laser process. The emitted and/or reflected light may be transmitted from the distal end of the operation optical path back to a receiving and monitoring unit, e.g. an OTDR with a spectrometer, by way of the high power fiber, or by way of a separate monitoring fiber.
Although the foregoing examples use monitoring signals based upon light, it is contemplated that such signals may also be electrical, acoustical, hydraulic based, gas based, and/or pressure based signals. Moreover, the embodiments and their components, of the foregoing examples may used in conjunction with other monitoring devices and/or systems that monitor activities and conditions other than the high power laser beam and beam path. Thus, the embodiments and their components, of the foregoing examples may combine with pressure, temperature and shock detection and monitoring devices and systems. Additionally the same monitoring fiber could be used for these sensors, as well as, the high power laser sensors. The components, systems and operations provided in the various figures and embodiments set forth in 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 example or a particular embodiment in a particular Figure.
Many other uses for the present inventions may be developed or released and thus the scope of the present inventions is not limited to the foregoing examples of uses and applications. Thus, for example, in addition to the forgoing examples and embodiments, the implementation of the present inventions may also be utilized in laser systems for hole openers, perforators, reamers, whipstocks, and other types of boring tools.
The present inventions 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.
In FIG. 5 there is provided a schematic of an embodiment of a high power laser drilling workover and completion system deployed in the field for use in drilling activities, and which may utilize the break detection methods and systems of the present invention. A control system as disclosed and taught in the following U.S. Patent Applications: Ser. No. 61/446,412, and co-filed patent application U.S. Publication No. 2012/0248078, the entire disclosures of each of which are incorporated herein by reference, may be used with this break detection system and drilling system. The control system may be expanded, or networked with other control systems, to provide an integrated control network for some, or all of the components disclosed in that deployment.
Thus, the laser drilling system 5000 is shown as deployed in the field in relation to the surface of the earth 5030 and a borehole 5001 in the earth 5002. There is also an electric power source 5003, e.g. a generator, electric cables 5004, 5005, a laser 5006, a chiller 5007, a laser beam transmission means, e.g., an optical fiber, optical cable, or conveyance device 5008, a spool or real 5009 (or other handing device) for the conveyance device, a source of working fluid 5010, a pipe 5011 to convey the working fluid, a down hole conveyance device 5012, a rotating optical transition device 5013 (e.g., an OSR), a high power laser tool 5014, a support structure 5015, e.g., a derrick, mast, crane, or tower, a handler 5016 for the tool and down hole conveyance device, e.g., an injector, a diverter 5017, a BOP 5018, a system to handle waste 5019, a well head 5020, a bottom 5021 of the borehole 5001, and a connector 5022.
The monitoring and detection system for the system 5000 has a monitoring device 5050, which has monitoring fibers 5051, and signal wire 5053 entering the OSR 5013. The signal wire 5053 is connected to a photodiode 5052 that is within the OSR 5013. A monitoring fiber 5051 leaves the OSR 5013 and is associated with the conveyance device 5008, and preferably adjacent to the high power laser fiber. The monitoring fiber has a plurality of backward reflection devices, e.g., 5051a, 5051b, 5051c, 5051d, 5051e, 5051f. 
In addition to the injector, gravity, pressure, fluids, differential pressure, buoyancy, a movable packer arrangement, and tractors, other motive means may be used to advance the downhole tool to its location of operation, such as for example to a predetermined location in a borehole, for example, the bottom of the borehole so that it may be laser-mechanically drilled to drill and advance the borehole.
The optical cable, preferably is a line structure, which may have multiple channels for transporting different materials, cables, or lines to a laser tool such as an electric motor laser bottom hole assemble, a laser cutting tool, a laser drilling tool, and a laser bottom hole assembly. Examples of such laser tools are disclose and taught in the following U.S. patent applications and U.S. Patent Application Publications: U.S. 2010/0044106 (issued as U.S. Pat. No. 8,511,401), U.S. 2010/0044104 (issued as U.S. Pat. No. 8,820,434), U.S. 2010/0044105 (issued as U.S. Pat. No. 8,424,617), Ser. Nos. 13/211,729, 13/222,931, 13/347,445, 13/366,882, 12/896,021 (issued as U.S. Pat. No. 8,627,901) and Ser. No. 61/446,042, the entire disclosures of each of which are incorporated herein by reference. The channels may be in, on, integral with, releasably connected to, or otherwise associated with the line structure, and combinations and variations of these. Further examples of optical fibers, optical cables, connectors and conveyance structures are disclosed and taught in the following U.S. Patent Applications and U.S. Patent Publications: Publication No. U.S. 2010/0044106 (issued as U.S. Pat. No. 8,511,401), Publication No. 2010/0215326, Publication No. 2012/0020631 (issued as U.S. Pat. No. 8,571,368), Ser. No. 13/210,581 (issued as U.S. Pat. No. 8,662,160), and Ser. No. 61/493,174, the entire disclosures of each of which are incorporated herein by reference.
In general, an optical assembly, an optical package, an optical component and an optic, that may be utilized with high power laser tools and systems, may be generally any type of optical element and/or system that is capable of handling the laser beam (e.g., transmitting, reflecting, etc. without being damaged or quickly destroyed by the beams energy), that is capable of meeting the environmental conditions of use (e.g., down hole temperatures, pressures, vibrates, etc.) and that is capable of effecting the laser beam in a predetermined manner (e.g., focus, de-focus, shape, collimate, power distribution, steer, scan, etc.). Further examples of optical assemblies, optical packages, optical components and optics are disclosed and taught in the following U.S. patent applications and U.S. Patent Application Publications: U.S. 2010/0044105 (issued as U.S. Pat. No. 8,424,617), U.S. 2010/0044104 (issued as U.S. Pat. No. 8,820,434), Ser. Nos. 13/222,931, 61/446,040, 61/446,312 and co-filed U.S. patent application Publication No. U.S. 2012/0275159 filed contemporaneously herewith, the entire disclosures of each of which are incorporated herein by reference.
In these methods, tools, systems and applications, the laser beam, or beams, may for example have 10 kW, 20 kW, 40 kW, 80 kW or more power; and have a wavelength in the range of from about 445 nm (nanometers) to about 2100 nm, preferably in the range of from about 800 to 1900 nm, and more preferably in the ranges of from about 1530 nm to 1600 nm, from about 1060 nm to 1080 nm, and from about 1800 nm to 1900 nm. Further, the types of laser beams and sources for providing a high power laser beam may be the devices, systems, optical fibers and beam shaping and delivery optics that are disclosed and taught in the following U.S. Patent Applications and U.S. Patent Application Publications: Publication No. U.S. 2010/0044106 (issued as U.S. Pat. No. 8,511,401), Publication No. U.S. 2010/0044105 (issued as U.S. Pat. No. 8,424,617), Publication No. U.S. 2010/0044103 (issued as 8,826,973), Publication No. U.S. 2010/0044102 (issued as U.S. Pat. No. 8,836,085), Publication No. U.S. 2010/0215326, Publication No. 2012/0020631 (issued as U.S. Pat. No. 8,571,368), Ser. No. 13/210,581 (issued as 8,662,160), and Ser. No. 61/493,174, the entire disclosures of each of which are incorporated herein by reference. The high power lasers for example may be fiber lasers or semiconductor lasers having 10 kW, 20 kW, 50 kW or more power and, which emit laser beams with wavelengths preferably in about the 1064 nm range, about the 1070 nm range, about the 1360 nm range, about the 1455 nm range, about the 1550 nm range, about the 1070 nm range, about the 1083 nm range, or about the 1900 nm range (wavelengths in the range of 1900 nm may be provided by Thulium lasers). Thus, by way of example, there is contemplated the use of four, five, or six, 20 kW lasers to provide a laser beam in a bit having a power greater than about 60 kW, greater than about 70 kW, greater than about 80 kW, greater than about 90 kW and greater than about 100 kW. One laser may also be envisioned to provide these higher laser powers.
High powered optical cables, spools of cables, creels, connectors and reels of cables of the type disclosed and taught in the following U.S. Patent Applications and U.S. Patent Application Publications: 2010/0044104 (issued as U.S. Pat. No. 8,820,434), 2010/0044103 (issued as U.S. Pat. No. 8,826,973), 2010/0215326, 2012/0020631 (issued as U.S. Pat. No. 8,571,368), Ser. Nos. 13/366,882, 61/493,174 and Ser. No. 13/210,581 (issued as U.S. Pat. No. 8,662,160), the entire disclosures of each of which are incorporated herein by reference, may be used in conjunction with the present systems. Thus, the optical cable or the conveyance structure may be: a single high power optical fiber; it may be a single high power optical fiber that has shielding; it may be a single high power optical fiber that has multiple layers of shielding; it may have two, three or more high power optical fibers that are surrounded by a single protective layer, and each fiber may additionally have its own protective layer; it may contain other conduits such as a conduit to carry materials to assist a laser cutter, for example oxygen; it may have other optical or metal fibers for the transmission of data and control information and signals; it may be any of the combinations set forth in the foregoing patents and combinations and variations thereof.
In FIG. 6 there is provided a schematic drawing of an embodiment of a laser room 600 and spool 601. That may be used in conjunction with a high power laser delivery system, for example of the type shown in FIG. 5. In the embodiment of FIG. 6 the laser room 600 contains a high power beam switch 603, a high power laser unit 602 (which could be a number of lasers, a single laser, or laser modules, collectively having at least about 5 kW, 10 kW, 20 kW, 30 kW 40 kW, 70 kW or more power), a chiller or connection to a chiller assembly 604 for the laser unit 602 and a control counsel 605 that preferably is in control communication with a control system and network 610. Additionally multiple laser may be combined with a high power beam combiner to launch about 40 kW, about 60 kW about 80 kW or greater down a single fiber. Preferably, the larger components of the chiller 604, such as the heat exchanger components, will be located outside of the laser room 600, both for space, noise and heat management purposes. The high power laser unit 602 is optically connected to the beam switch 603 by high power optical fiber 606. The beam switch 603 optically connects to spool 601 by means of a high power laser fiber 607 and an optical slip ring 608, which in turn optically and rotationally connects to the optical cable 609. In higher power systems, e.g., greater than 20 kW the use of multiple fibers, multiple beam switches, and other multiple component type systems may be employed. These will, among other things provide greater safety and reliability to such higher power systems. The optical cable is then capable of being attached to a high power laser tool. A second optical cable 611, which could also be just an optical fiber, leaves the beam switch 603. This cable 611 could be used with a different spool for use with a different tool, or directly connect to a tool. Electrical power can be supplied from the location where the laser room is located, from the mobile unit that transported the laser room, from separate generators, separate mobile generators, or other sources of electricity at the work site or bought to the work site.
The monitoring and break detection system for the system 600, has an OTDR 641 in communication with the control network 610. The OTDR has a monitoring fiber 640 that is optically associated with the OSR 608. A signal wire 631 is connected to a photodiode 630, with in or on the OSR 608. The signal wire 631 is connected to the network, either directly or through the OTDR 641.
In another example a distributed temperature sensing fiber with sequential bragg gratings for monitoring the temperature and pressure along the entire fiber and detecting anomalies in the temperature of the fiber and its armor is utilized. This fiber may be the high power transmission fiber, a separate fiber adjacent to the high power transmission fiber, or a separate fiber removed from the high power transmission fiber but in detection range of the high power transmission fiber, e.g., within the conveyance structure but outside of a protective member around the high power transmission fiber.
There may also be employed a fiber with gratings sequentially positioned along the fiber to collect light from the optical fiber along the length of the fiber and transmit it back to the top of the hole to allow continuous monitoring of the light leaking out of the fiber and allowing any anomaly to be detected prior to a failure. In this manner the high power transmission fiber functions as the monitoring fiber as well. A detection device, such as spectrometer may be utilized to analyze the light leaking out of the fiber and provide a basis for a correlation to the condition of the system.
In a break detection and monitoring system there may also be utilized a spectrometer monitoring the back reflection signal on the fiber. Thus, in the event of a failure of an optic or the fiber the wavelength of laser light back-reflected along the fiber is greatly enhanced and can be used to detect remotely when a failure has occurred downhole. This system could have a thin foil packaged adjacent to the optical fiber to conduct an electrical signal to the bottom of the hole and the stainless steel tube encapsulating the fiber would be used as the return for the interlock signal. This system may also employ two thin foils that are packaged adjacent to the optical fiber in the metal tube and connected at the bottom of the hole to the connector switch, which indicates the connector (examples of connectors are disclosed in U.S. Patent Application Ser. No. 61/493,174) is seated. Additionally, a thermal switch may be included in the connector housing connected in series with the thin foils for the purpose of stopping the laser in the event of an overheat situation in the connector. The thermal switch provides additional protection to the downhole optic system preventing additional damage and propagation of damage through the umbilical or conveyance structure.
Thus, for example, a spectrometer may be used to monitor a backreflected signal from a tool at the distal end of the fiber. A controller, computer, the spectrometer or other device may then integrate the backreflected signal over different wavelength regions to look for characteristic spectral signatures that indicate damage to optics and the fiber, or other components along the optical paths. Also, a method using a spectrometer to monitor the back reflected signal from the tool at the distal end of the fiber and monitoring the magnitude of the backreflected signal at the laser wavelength and using that to detect the onset of damage to the optics and the fiber, may be employed.
Preferably in a high power laser system a controller is in communication, via a network, cables fiber or other type of factory, marine or industrial data and control signal communication medium with the laser tool and potentially other systems at a work site. The controller may also be in communication with a first spool of high power laser cable, a second spool of high power laser cable and a third spool of high power laser cable, etc. The monitoring and detection systems would preferably be integrated into the control network.
One or more high power optical fibers, as well as, lower power optical fibers may be used or contained in a single cable that connects the tool to the laser system, this connecting cable could also be referred to herein as a tether, an umbilical, wire line, or a line structure. The optical fibers may be very thin on the order of hundreds e.g., about greater than 100, of μm (microns). These high power optical fibers have the capability to transmit high power laser energy having many kW of power (e.g., 5 kW, 10 kW, 20 kW, 50 kW or more) over many thousands of feet. The high power optical fiber further provides the ability, in a single fiber, although multiple fibers may also be employed, to convey high power laser energy to the tool, convey control signals to the tool, and convey back from the tool control information and data (including video data). In this manner the high power optical fiber has the ability to perform, in a single very thin, less than for example 1000 μm diameter fiber, the functions of transmitting high power laser energy for activities to the tool, transmitting and receiving control information with the tool and transmitting from the tool data and other information (data could also be transmitted down the optical cable to the tool). As used herein the term “control information” is to be given its broadest meaning possible and would include all types of communication to and from the laser tool, system or equipment.
The tools that are useful with high power laser systems, and which can incorporate or utilize the optical assemblies described herein, many generally be laser drills, laser bottom hole assemblies, laser cutters, laser cleaners, laser monitors, laser welders and laser delivery assemblies that may have been adapted for a special use or uses. Configurations of optical elements for collimating and focusing the laser beam can be employed with these tools to provide the desired beam properties for a particular application or tool configuration.
Such tools for example may be used for drilling cleaning, resurfacing, removal, and clearing away of unwanted materials, e.g., build-ups, deposits, corrosion, or substances, in, on, or around a structures, e.g. the work piece, or work surface area. Such unwanted materials would include by way of example rust, corrosion, corrosion by-products, degraded or old paint, degraded or old coatings, paint, coatings, waxes, hydrates, microbes, residual materials, biofilms, tars, sludges, and slimes.
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

1. A system for advancing a borehole in hard rock, the system comprising:
a. a source of high power laser energy, the laser source capable of providing a laser beam having at least 20 kW of power;
b. a laser bottom hole assembly;
c. a high power optical fiber placing the laser bottom hole assembly in optical communication with the laser source thereby defining an operational beam path; the optical fiber having a length of at least about 1,000 feet; and,
d. a means for monitoring and detecting a condition of the high power laser energy along the high power optical fiber and thereby along the operational beam path,
wherein the means for monitoring and detecting comprises a plurality of light detecting devices that are distributed along the high power optical fiber and in optical proximity to the high power optical fiber,
wherein the plurality of light detecting devices is capable of detecting light leaked from the high power optical fiber and sends a signature indicating a location and the condition of the high power optical fiber to a monitoring device via a monitoring fiber.

2. The system of claim 1. Wherein the operational beam path is at least about 5,000 feet long.

3. The system of claim 1, wherein the monitoring and detecting means comprises a leak detector associated with a fusion splice.

4. The system of claim 1, wherein the monitoring and detecting means comprises a plurality of light detecting devices, associated with a monitoring fiber, wherein the monitoring fiber is associated with an optical time-domain reflectometer (OTDR), whereby the light transmitted by a light detecting device is analyzed and correlated to a condition along the operation beam path.

5. The system of claim 1, wherein the monitoring device receives light transmitted by the plurality of light detecting devices, analyzes and correlates to the condition along the operation beam path.

6. The system of claim 5, wherein the light transmitted by the plurality of light detecting devices comprises high power laser back reflections.

7. The system of claim 1, wherein the monitoring and detecting means comprises a fiber splice and an optical slip ring (OSR) comprising a photodiode, and wherein the OSR is placed in close proximity to the fiber splice.

8. The system of claim 7, wherein the photodiode is electrically associated with the monitoring and detecting means via a signal wire.

9. The system of claim 1, wherein the monitoring and detecting means comprises a distributed temperature sensing fiber with sequential bragg gratings for monitoring temperatures along the operational beam path and detecting anomalies in the temperatures.

10. The system of claim 1, wherein the monitoring and detecting means comprise a fiber having gratings sequentially positioned along a length of the fiber, wherein the gratings are configured to collect light and transmit the collected light to the monitoring device to detect an anomaly prior to a failure.

11. The system of claim 1, wherein the plurality of light detecting devices are a plurality of backward reflection devices.

12. The system of claim 11, wherein the plurality of backward reflection devices are minors, gratings, and a combination of mirrors and gratings.

13. The system of claim 1, wherein the plurality of light detecting devices modulate or alter an optical signal to provide the unique signature.

14. The system of claim 1, wherein plurality of light detecting devices are disclosed at 100 foot intervals.

15. The system of claim 1, further comprises a cladding stripper device configured to remove light from a cladding of the high power optical fiber.

16. The system of claim 15, wherein the removed light is optically transmitted to the monitoring device via the monitoring fiber.

17. A system for monitoring an operational high power laser beam path associated with a high power laser drilling system, the system comprising:
a. a monitoring fiber associated with a high power laser fiber;
b. the monitoring fiber having a plurality of light detection devices positioned along the high power laser fiber and in optical proximity to the high power laser fiber; and,
c. a monitoring device in optical association with the monitoring fiber;
d. wherein high power laser beam is transmitted through the high power laser fiber to a high power laser tool, and wherein the plurality of light detection devices are capable of detecting light leaked from the high power laser fiber,
wherein the plurality of light detection devices is optically associated with the monitoring device via the monitoring fiber and sends a signature indicating a location and the condition of the operational high power laser beam to the monitoring device via the monitoring fiber.