Composite photon pulse fracturing tool and related methods

Abstract

The present application relates to systems and methods for stimulating hydrocarbon-bearing formations using a hybrid downhole tool using a high power laser and chemicals.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Patent Application No. 16 / 439,405, filed on June 12, 2019, entitled “HYBRID PHOTONIC-PULSED FRACTURING TOOL AND RELATED METHODS,” the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to composite tools and related systems and methods for using high power lasers and chemicals to stimulate hydrocarbon-bearing formations. Background Art

[0004] Wellbore stimulation is a branch of petroleum engineering that focuses on how to promote the flow of hydrocarbons from the formation to the wellbore for production. In order to produce hydrocarbons from the target formation, the hydrocarbons in the formation need to flow from the formation to the wellbore in order to be produced and flow to the surface. The flow from the formation to the wellbore is achieved by the permeability of the formation. When the formation permeability is low, stimulation is performed to promote flow. Stimulation can be performed around the wellbore and in the formation to build a network in the formation. The first step of stimulation is usually to perforate the casing and cement the well to reach the formation. One way to perforate the casing is to use shaped charges. The shaped charge is lowered into the wellbore to the target release zone. The release of the shaped charge creates a short tunnel that penetrates the steel casing, cement and into the formation.

[0005] There are several disadvantages to using shaped charges. For example, shaped charges form a dense layer around the tunnel, which reduces permeability and thus production. The high-velocity impact of the shaped charge pulverizes the rock formation and produces very fine particles that block the pore throats of the formation, reducing flow and production. There is a possibility of melt formation in the tunnel. The geometry and direction of the tunnel formed by the shaped charge cannot be controlled. There are limitations on the penetration depth and diameter of the tunnel. There are risks when handling explosives on the ground.

[0006] The second stage of stimulation usually involves pumping fluid through the tunnels formed by the shaped charges. The fluid is pumped at a rate that exceeds the formation fracture pressure causing the formation and rock to break and fracture, which is called hydraulic fracturing. Hydraulic fracturing is mainly performed using water-based fluids called hydraulic fracturing fluids. Hydraulic fracturing fluids can damage formations, especially shales. Hydraulic fracturing creates fractures in the formation, creating a network between the formation and the wellbore.

[0007] There are several disadvantages to hydraulic fracturing. First, as mentioned above, hydraulic fracturing can damage the formation. In addition, the direction of the fracturing cannot be controlled. Fractures have been known to close. There are risks above ground due to the high water pressure in the pipes. There are also environmental issues related to the components added to the hydraulic fracturing fluid and the need for the millions of gallons of water required for hydraulic fracturing.

[0008] High-powered laser systems can also be used in downhole applications to stimulate the formation by, for example, drilling clean, controlled wells with lasers. Laser drilling often saves time because it does not require a pipe connection like conventional drilling, and is a more environmentally friendly technology with far fewer emissions because the laser is electrically powered. However, there are also limitations to the placement and maneuverability of laser tools for effective downhole use. Summary of the invention

[0009] Generally speaking, the present disclosure relates to underground applications of composite tools to establish communication between a wellbore and a hydrocarbon-bearing formation to produce hydrocarbon fluids. The disclosed tool combines a high-power laser with a fracturing technique that uses pulsed energy generated by a chemical reaction. The high-power laser can be used to drill into the ground in any direction and orientation, regardless of the stress level. The tool includes one or more chambers for storing and transporting chemicals that react to generate high pressure and temperature to form a fracturing network. This technology achieves unique waterless fracturing and maximizes production. This technology can be used in conventional and unconventional reservoirs. The present disclosure also relates to different systems and methods for using composite tools in different configurations and for different applications for unlocking a reservoir and increasing the volume of the reservoir stimulated to increase production.

[0010] The disclosed method can drill and fracture a formation with one tool, which includes two technologies that are combined to unlock potential reservoirs by, for example, controlling fracture depth and location, which enables a variety of new recovery methods. The technology includes combining lasers with chemicals to perform multi-stage fracturing, while other technologies require different tools to perform a single operation, for example, requiring a laser tool for perforating or drilling, and another tool for fracturing the formation using chemicals.

[0011] Generally speaking, the disclosed composite downhole tool is superior to known technologies because it does not require hydraulic fracturing, thereby limiting the demand for scarce fresh water resources; increases production from tight reservoirs by improving the fracture network; and is able to bypass non-oil producing areas within the formation by controlling tool orientation and fracture depth.

[0012] In one aspect, the present application relates to a composite tool for stimulating a hydrocarbon-bearing formation. The tool comprises an elongated tool body having one or more chemical chambers and a laser head coupled to a distal end of the tool body and configured to operate within a wellbore of a formation.

[0013] The chemical chamber includes: a storage device for storing at least one chemical for reaction and delivery to the wellbore; and a delivery device for delivering the product of the chemical reaction to the wellbore. The laser head includes: one or more optical transmission media, the one or more optical transmission media are part of an optical path from a laser generation unit configured to generate a raw laser beam, the one or more optical transmission media are configured to transmit the raw laser beam; and an optical component, the optical component is coupled to the optical transmission medium and configured to shape the laser beam for output.

[0014] In various embodiments of the aforementioned aspects, the chemical chamber further comprises a mixing chamber disposed in the chemical chamber and configured to receive the chemical stored in the chemical chamber. The storage device of the chemical chamber may include: two containers configured to store two or more chemicals for mixing; a piston configured to be advanced within the two containers to discharge the chemicals from the two containers to the mixing chamber; and a one-way valve disposed at a distal end of each of the two containers and configured to transfer the chemical to the mixing chamber.

[0015] In some embodiments, the delivery device includes one or more pressure relief valves disposed in the wall of the chemical chamber, and the chemical chamber itself may include a rotating assembly for orienting the chemical chamber and the delivery device toward a desired destination. The chemical chamber may also include a heating device for triggering a reaction of one or more chemicals stored in the heating device.

[0016] In various embodiments, the laser head includes a housing that houses at least a portion of the optical assembly and is configured to move within the wellbore to direct the laser beam relative to the wellbore. The laser head may also include a plurality of directional nozzles disposed around the periphery of the laser head and configured to provide thrust to the laser head to control the movement and orientation of the tool within the wellbore. In some embodiments, the plurality of directional nozzles are movably coupled to the laser head to allow the directional nozzles to rotate or pivot relative to the laser head, thereby providing at least forward motion, reverse motion, rotational motion, or a combination thereof to the laser head.

[0017] The laser head may further include a flushing assembly disposed at least partially within or adjacent to the laser head and configured to deliver a flushing fluid to an area near the output laser beam. In some embodiments, at least a portion of the flushing nozzles are vacuum nozzles connected to a vacuum source and configured to remove debris and gaseous fluid from the area near the output laser beam. The tool may further include at least one centralizer coupled to the tool and configured to maintain the tool in a position relative to an external casing in the wellbore.

[0018] In other embodiments, the tool comprises an articulated arm disposed between the laser head and the laser generating unit. The articulated arm may comprise a snake-like robot having a motion device for manipulating the tool within the wellbore. The motion device may comprise at least one of an electric motor or a hydraulic actuator. The tool may comprise a control system configured to control at least one of movement or operation of the tool.

[0019] Additionally, the tool may include at least one rotation assembly configured to rotate at least one of the laser head or the chemical chamber relative to a central axis of the tool body. In some embodiments, the tool includes a plurality of chemical chambers and a plurality of rotation systems, wherein the chemical chambers are separated by the rotation systems so that each chemical chamber can be independently rotated.

[0020] In another aspect, the present application relates to a method for stimulating a hydrocarbon-bearing formation using a tool. The method comprises the following steps: positioning a composite tool in a wellbore in a formation, wherein the composite tool comprises a chemical delivery device and a laser head; transmitting a raw laser beam generated by a laser generating unit at a starting point of an optical path through one or more optical transmission media, wherein the optical path comprises the one or more optical transmission media; directing the laser head of the composite tool in the wellbore; delivering the raw laser beam to an optical assembly disposed in the laser head; manipulating the raw laser beam using the optical assembly to generate an output laser beam; delivering the output laser beam to the formation; directing the chemical delivery device of the composite tool in the wellbore; triggering a chemical reaction in the composite tool to generate energy; and delivering the energy to the wellbore.

[0021] In various embodiments, the chemical reaction is triggered by at least one of heating or mixing chemicals. The laser head can be directed within the wellbore using a plurality of nozzles disposed around the periphery of the laser head. Additionally, the step of positioning the composite tool within the wellbore can be accomplished via an articulated arm and a sensor.

[0022] definition

[0023] In order to make this application easier to understand, some terms are first defined below. Other definitions of the following terms and other terms may be shown throughout the specification.

[0024] In this application, unless the context clearly indicates otherwise, the terms "a" and "an" may be understood to mean "at least one". As used in this application, the term "or" may be understood to mean "and / or". In this application, the term "comprising" may be understood to cover the components or steps listed in detail, whether alone or together with one or more other components or steps. As used in this application, the term "comprise" and variations of the term (such as "comprising" and "comprises") are not intended to exclude other additives, components, integers or steps.

[0025] About, approximately: As used herein, the terms "about" and "approximately" are used equivalently. Unless otherwise specified, the terms "about" and "approximately" may be understood to allow standard deviations as understood by those of ordinary skill in the art. In the case of providing a range herein, the endpoints are included. Any number used in conjunction with or without about / approximately in this application is intended to cover any normal fluctuations understood by those of ordinary skill in the relevant art. In some embodiments, unless otherwise specified or apparent in the context (unless this number exceeds 100% of the possible value), the term "about" or "approximately" refers to a certain range of values ​​(larger or smaller than the reference value) of 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1% or less in either direction of the reference value.

[0026] Near a wellbore: As used herein, the term "near a wellbore" refers to a region of rock formations in or around a wellbore. In some embodiments, "near a wellbore" refers to a surface region adjacent to a wellbore opening, such as less than 35 meters (m) from the wellbore (e.g., less than 30 meters, less than 25 meters, less than 20 meters, less than 15 meters, less than 10 meters, or less than 5 meters from the wellbore).

[0027] Substantially: As used herein, the term "substantially" refers to the qualitative condition of exhibiting full or nearly full range or degree of a characteristic or property of interest.

[0028] Perimeter: As used herein, the term "perimeter" refers to the outer boundary or perimeter of an object, regardless of its shape, for example, whether it is circular, oval, rectangular, or a combination thereof.

[0029] These and other objects, advantages and features of the systems and methods disclosed herein will become apparent by reference to the following description and drawings.In addition, it should be understood that the features of the various embodiments described are not mutually exclusive, but can exist in various combinations and permutations. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In the drawings, the same reference numerals generally refer to the same parts throughout the different views. In addition, the drawings are not necessarily drawn to scale, and the emphasis is actually primarily on illustrating the principles of the disclosed systems and methods rather than being intended to be limiting. For clarity, not every component may be labeled in every figure. In the following description, reference is made to various embodiments described in the following figures, in which:

[0031] Figure 1 is a graphical representation of reactant potential energy as heat during a chemical reaction according to one or more embodiments;

[0032] Figure 2 is an enlarged schematic diagram of a composite tool according to one or more embodiments;

[0033] Figure 3 According to one or more embodiments Figure 2 An enlarged exploded schematic diagram of a portion of a chemical chamber of a tool in a first stage of operation;

[0034] Figure 4 According to one or more embodiments Figure 2 An enlarged exploded schematic diagram of the portion of the chemical chamber of the tool in the second operation stage;

[0035] Figure 5 According to one or more embodiments Figure 2 An enlarged exploded schematic diagram of the portion of the chemical chamber of the tool in the third operation stage;

[0036] Figure 6 According to one or more embodiments Figure 2 An enlarged schematic diagram of the portion of the chemical chamber of the tool in the fourth operating stage;

[0037] Figure 7 According to one or more embodiments Figure 2 An enlarged schematic diagram of a portion of a chemical chamber of a tool in FIG. 1 , showing the external configuration of the valve;

[0038] Figure 8 is an enlarged schematic diagram of a portion of an alternative chemical chamber of a composite tool according to one or more embodiments;

[0039] Fig. 9A and 9Bis an enlarged schematic diagram of a portion of an alternative composite tool according to one or more embodiments;

[0040] Fig.10 is an illustration of deployment of a composite downhole tool according to one or more embodiments;

[0041] Fig.11 is an illustration of a method of using a composite downhole tool according to one or more embodiments;

[0042] Fig.12 is an illustration of a fracture network formed by a composite downhole tool according to one or more embodiments; and

[0043] Fig.13A and 13B is a diagram of a fracture network formed by a composite downhole tool for flow in either a vertical or horizontal orientation. DETAILED DESCRIPTION

[0044] The present application relates to tools and related systems and methods for establishing communication between a wellbore and a hydrocarbon-bearing formation to increase production and improve recovery of conventional and unconventional reservoirs. The technology of the present application provides a non-destructive alternative means for several downhole excitations and applications, including drilling, notching, and fracturing. Typically, a laser tool is combined with a chemical chamber disposed in the tool body, which can discharge chemicals that are energized when mixed or triggered to deliver pressure and temperature energy to the formation. This energy can be used in different modes and architectures to establish communication between a dense formation and a wellbore to produce hydrocarbons.

[0045] Figure 1 Graphically depicts the potential energy of chemical reactants released as heat during a chemical impulse reaction. In general, the atoms and molecules of a chemical have energy that can be used for different applications. Some chemical reactions are able to release energy in different forms, such as heat, which are called exothermic reactions. The amount of heat released by an exothermic reaction can be measured if the reaction is carried out at a constant temperature and constant pressure. In chemistry, the amount of heat released is called enthalpy and can be described by Equation 1:

[0046] ΔH=H 产物 -H 反应物 (where H = heat).

[0047] Many exothermic reactions produce gases among the reaction products. These types of reactions can act on their surroundings due to the pressure created by the release of the gas, as shown in Equation 2:

[0048] w = -PΔV (where w = work, P = pressure, and V = volume)

[0049] Additionally, the pressure and volume of the released gas may be calculated using the ideal gas law known to those skilled in the art: PV = nRT.

[0050] Therefore, based on the foregoing information, chemical reactions can be used to generate energy that can be used to form fractures in the formation, and the pressure and temperature of the reaction can be estimated.

[0051] Below is an example of a chemical reaction that produces a gas by mixing chemicals together. As shown in the following reaction, sodium nitrite (NaNO 2 ) and aminosulfonic acid (HSO 3 NH 2 ) will produce nitrogen gas (along with sodium bisulfate and water):

[0052] NaNO 2 +HSO 3 NH 2 →N 2 +NaHSO 4 +H 2 O.

[0053] As shown in the following reaction, sodium bicarbonate (NaHCO 3 ) and acetic acid (HC 2 H 3 O 2 ) will produce carbon dioxide gas (along with sodium acetate and water):

[0054] NaHCO 3 +HC 2 H 3 O 2 →NaC 2 H 3 O 2 +H 2 O+CO 2 .

[0055] Some chemicals require heat to start reacting, such as ammonium nitrite (NH 4 NO 2 ) decomposition. This reaction proceeds very slowly at room temperature; however, if triggered at a temperature of about 60°C-70°C, the reaction occurs very quickly, producing a very large amount of nitrogen, as shown in the following reaction:

[0056] NH 4 NO 2 =>N 2 +H 2 O.

[0057] Another example is sodium azide (NaN 3), which requires a temperature of about 300°C to start the reaction:

[0058] 2NaN 3 =2Na+3N 2 .

[0059] Figure 2 A composite tool 100 is depicted in accordance with one or more embodiments. As shown, the tool 100 includes an elongated body 102, which in some embodiments includes an articulated arm 101, as will be described in greater detail below. Figure 2 Also depicted is a laser head 104 connected to the distal end of the tool body 102. The tool body 102 also includes one or more chemical reaction chambers 106 that are isolated and used to store and mix chemicals. In some embodiments, there are multiple evenly spaced chambers 106 along the length of the tool body 102; however, the number and spacing can be selected to suit a particular application or reservoir. For example, if the tool 100 is used for a dense reservoir, the spacing of the chambers 106 will be closer and the number of chambers 106 will be greater. Figure 3-8 The chamber will be described in more detail.

[0060] refer to Figure 2 , 9A , 9B and 10, laser head 104 ( Fig. 9A 904) includes a cable assembly ( Fig.10 546 of them Fig. 9A 946) and the laser generation unit ( Fig.10 544) connected to the optical component 105 ( Fig. 9A 905), the laser generating unit 544 is located on the ground 542 near the wellbore 544 and is configured to provide: a device for positioning and manipulating the tool assembly 100, 500, 900 in the wellbore 540; a device for flushing the assembly 107 ( Fig. 9B The optical assembly 105 includes a controller and a fluid (gas or liquid) source for the tool 100, 500, 900, and a controller and device for delivering laser energy to the optical assembly 105. The cable assembly 546 provides energy (electricity) to the tool 100, 500, 900 and includes an optical transmission medium, such as an optical fiber, for transmitting laser energy to the tool. The cable is wrapped to protect it from the downhole environment, wherein the cable jacket can be made of any commercially available material to protect the cable from high temperature, high pressure and fluid / gas / particle intrusion of the cable.

[0061] Typically, the laser head 104 ( Fig. 9B 904 in the figure) includes a protective housing, which, according to some embodiments, is a transparent housing formed of glass or sapphire material. In some embodiments, only the distal end of the housing is transparent or includes a light source for emitting the output light beam 109 ( Fig. 9AThe raw laser output end of the cable 546 is operably connected to the optical assembly 105 within the housing. The optical assembly 105 is used to shape the output laser beam 109 and deliver it to the wellbore.

[0062] The optical assembly 105, 905 may include various optical components, such as lenses, prisms, and collimators, as needed to shape and size the desired output beam 109, 909. In some embodiments, the cover glass also protects the optical assembly 105 by, for example, preventing dust and vapor from entering the laser head 104. The various optical components previously described may be any material, such as glass, plastic, quartz, crystal, or other material that can withstand the environmental conditions to which the optical assembly is subjected. The shape and curvature of any lens may be determined by one skilled in the art based on the application of the downhole laser system.

[0063] In some embodiments, in addition to the optical fiber 110 for beam delivery, the cable 546 includes another low-power optical fiber cable 112 for heating. The power of the cable 112 can be less than 5kW. The cable 112 has two functions: measurement and recording of temperature and pressure; and generation of heat for the chemical reaction. The specific placement of the cable 112 on the tool 100 can be varied to suit a particular application. In some embodiments, the cable 112 is placed on the outer surface of the chemical chamber 106 to provide heat directly to the chamber 106.

[0064] Figure 2 The tool 100 depicted is configured to be lowered downhole by any service provider using a solenoid unit, logging cable, or tractor as known in the art. The tool 100 includes an articulated arm 101, which is sometimes referred to as a "snake robot." Fiber optic cables 110, 112 may be embedded in the articulated robotic arm 101 ( Fig. 9A 901 in which the arm is powered by an electric or hydraulic actuator and the orientation of the tool 100, 900 is determined by an orientation device 111 ( Fig. 9B 911) in, or by the tool itself if a motor is built into the tool to orient the tool.

[0065] In addition, not only the fiber optic cable, but also the main cable 546 or at least a portion thereof may be placed or embedded in the robot arm 101. The tool 100 or a portion thereof (e.g., the laser head 104) may also include one or more low-power fiber optic sensors for temperature and pressure recording, and one or more acoustic cameras ( Fig. 9B903 in). The function of the camera is to visualize the laser head 104 and the surrounding area while characterizing the formation. The data captured from the acoustics (in addition to the image) is the velocity of the sound waves propagating and reflecting within the formation, which can be used to calculate the mechanical properties of the formation, predict formation stability, evaluate tool performance, and support tool orientation and troubleshooting.

[0066] Typically, acoustic sensing 903 can provide information when drilling and guide tools by measuring formation density (similar to geosteering). By understanding density, formations and structures can also be understood. Integrated acoustics provide high-definition reservoir characterization and mapping. For example, when the tool 100 penetrates the formation, the tool will send real-time data to the ground to the operator, and the operator can teach the tool 100 to adhere to a specific density range without penetrating other ranges, such as a sandstone density range between 2.2 and 2.6 grams per cubic centimeter (g / cc), so the tool will follow and penetrate only sandstone, while providing a map of the sandstone structure. Acoustics also provide vision through an acoustic camera. These features enable the tool 100 to target only hydrocarbon layers. In addition, the information provided by acoustics can be used to calculate the mechanical properties of the formation and generate fault images. Machine learning can also be used to "teach" the tool how to self-navigate the formation through the information provided by acoustic and fiber optic sensors 913.

[0067] Tool 100 can be programmed to navigate and drill in a specified rock density using acoustic sensing and sound waves as a monitoring tool to guide the snake robot. More specifically, tool 100 will send and receive sound waves, and based on the speed difference, the tool can be guided to the target formation or identify a specific underground structure as the data is sent directly to the surface to control the snake robot, or the snake robot can be pre-programmed to analyze speed and steering based on these sound waves. As mentioned above, more details of the snake robot and acoustic sensing of the present application are in Fig. 9A and 9B Depicted in.

[0068] In addition, the tool 100 may also include a plurality of directional nozzles 111, 911 and a flushing system 107, 907. The tool 100, 900 also includes a centralizer or packer 114, 914 to centralize the tool 100, 900 and isolate the zone when necessary so that a specific task can be performed in the zone after reaching the target. The centralizer 114, 914 can be placed at various points along the tool 100, 900 as needed to adapt to a specific application. The centralizer 114, 914 supports the weight of the tool body and can be spaced along the tool 100, 900 as needed to accommodate the tool 100, 900 extending deeper into the formation. The centralizer 114, 914 can be metal, polymer or any other suitable material. Those of ordinary skill in the art will be familiar with suitable materials. In some embodiments, the centralizer 114, 914 may include a spring or a damper, or both. In some embodiments, the centralizer includes a solid piece of deformable material, such as a polymer or an expandable packer. In some embodiments, the centralizer may include a hydraulic device or a pneumatic device, such as an air bag.

[0069] One of the features of tool 100 is its precise control of the movement and position of laser head 104 within the wellbore. Tool 100 can also be positioned and oriented by a snake-like robot. Means for sensing the orientation and position of tool 100 within the wellbore are also provided, such means including various sensors and imaging known to those skilled in the art.

[0070] In the illustrated embodiment, the orientation device 111, 911 includes a plurality of nozzles disposed around the periphery of the laser head 104, 904. The nozzles may be coupled to the housing of the laser head 104, 904 by known mechanical means, either fixed (e.g., by fasteners or bonding) or movable (e.g., by ball joints or servo motors). Typically, the nozzles will be movably coupled to the laser head 104, 904 and controlled by the control system and the expansion tool 100 / 900 to provide forward, reverse, or rotational motion to the laser head 104, 904.

[0071] Typically, the tool 100 / head 104 is oriented by controlling the flow of a fluid (liquid or gas) through a nozzle. For example, by directing the fluid to flow in a rearward direction (opposite to the direction of the output laser beam 109), the tool 100 will be propelled forward in the wellbore by utilizing a thrust effect, wherein the opening of the nozzle faces the opposite direction of the tool head 104 and the fluid flows rearward, thereby providing thrust to move the tool 100 forward. Controlling the flow rate can control the speed of the tool 100 within the wellbore. The fluid used to provide thrust can be supplied from the surface and delivered through a fluid line included in the cable 546.

[0072] In some embodiments, there are four (4) nozzles evenly spaced around the laser head 104, and each nozzle can be controlled individually. For example, if only one nozzle is turned on, the tool 100 will turn in the opposite direction of the nozzle. The degree of rotation depends on the controlled flow rate from the nozzle. If all nozzles are turned on evenly, the tool will move linearly forward or backward depending on the position of the nozzle. For example, see Fig. 9B .

[0073] As previously described, for example, the nozzle may be movably mounted to the laser head 104 by a servo motor with a swivel joint that controls whether the nozzle end faces rearward (forward motion), forward (reverse motion), or in alignment with the central axis 148 ( Fig. 9A 948 in the figure) at a certain angle (rotational motion or a combination of linear and rotational motion, depending on the angular displacement of the nozzle relative to the center). For example, if the nozzle is aligned perpendicular to the central axis 148, the nozzle will only provide rotational motion. If the nozzle is parallel to the central axis 148, the nozzle will only provide linear motion. Any other angular position relative to the central axis 148 can provide a combination of rotational motion and linear motion.

[0074] Return to reference Figure 2 The flushing assembly 107 includes a plurality of flushing nozzles disposed within or near the laser head 104 and configured to remove dust or other particles from the outer surface of the laser head and the area near the laser head 104 so that the path of the laser beam 109 is not obstructed, because debris absorbs energy, resulting in reduced energy delivered to the formation. In addition, debris may contaminate the cutting area and damage the laser head 104 or interfere with, bend or scatter the laser beam 109. Suitable flushing fluids may be gases (e.g., high pressure air), or liquids. The flushing fluid should be transparent to the laser beam wavelength. According to various embodiments, at least a portion of the nozzles are vacuum nozzles connected to a vacuum source and adapted to remove debris and gaseous fluids from the outer periphery of the laser head 104.

[0075] Figure 3-8 The chemical chambers 106, 206 are described in greater detail. Figure 3 A single chamber is depicted for mixing and triggering reactions in the pre-mixing stage, with chemicals in separate storage containers 218a, 218b. Typically, each chamber includes a rotation assembly 230 disposed at one end thereof to rotate the chamber to a target position as desired. In some embodiments, the chamber can be pre-rotated to a set position before lowering the tool 200 or rotated in situ by electrical or hydraulic power controlled from the ground. The rotation assembly 230 can be used to rotate the chamber 206 relative to the tool body 102 and other chambers.

[0076] Each chamber 206 may also include a centralizer 214 to centralize and lock the tool in the desired target position to ensure accurate operation and orientation. A piston 228 is included to push the chemical into the storage area 216. Figure 3 As shown, storage area 216 includes a separator / divider 217 to separate area 216 into a first chemical storage container 218a and a second chemical storage container 218b. This arrangement is used in situations where the chemicals are triggered by mixing, and the storage containers include one or more one-way valves 222 to allow the chemicals pushed by piston 228 to enter the mixing chamber 224. Chamber 206 also includes a pressure relief valve 208 preset at a certain pressure, which acts like a bursting disc to allow pressurized gas to be released into the formation. In some embodiments, pressure relief valve 208 can be preset to release at 200psi, where the reaction can generate a pressure of 4000psi.

[0077] One end of the chamber 206 includes an additional rotating head 231 to assist in the rotation of the chamber so that both the rotating head 231 and the chamber rotate in the same direction. The rotating head 231 at this end may be equipped with a reinforcing plug 226 to prevent energy from leaking or otherwise leaving the tool 200 in an undesirable direction or damaging the tool. The chamber 206 is designed to mix chemicals to trigger a reaction, in other embodiments, the chemicals are triggered by heat, where a fiber optic heating cable 212 is used to generate heat to trigger the reaction; however, other heat sources such as microwaves or filaments may also be used. The other fiber optic cable 210 shown is the main fiber optic, which is used to deliver the original beam to the laser head.

[0078] Figure 4 Depicted Figure 3 The chamber 206 is not in the chamber 206, but the piston 228 is in operation so that the chemical is pushed through the one-way valve 222 into the mixing chamber 224 by the forward movement of the piston 228. The piston 228 can be moved hydraulically, pneumatically or by an electric actuator. The operation of pushing the chemical into the mixing chamber 224 should be completed quickly; so that all of the chemical enters the chamber 224, ensuring that all of the volume is present in the chamber to perform the necessary reaction.

[0079] Typically, chemicals are loaded into the tool at the surface, and then the tool is lowered and stabilized at one or more desired target zones in the wellbore. In some embodiments, the tool may include necessary conduits to introduce chemicals into the tool after the tool has been positioned; for example, in the case where multiple replicate reactions are required.

[0080] Figure 5 Depicted Figure 3 chamber 206, but piston 228 has been fully advanced and the chemicals have mixed, thereby triggering the reaction. Figure 5As can be seen in the figure, the chemicals 220 are all in the mixing chamber 224, where the chemicals will react. One or more pressure relief valves 208 will open to release the chemicals and close after all the chemicals have been released. Due to the force generated by the chemical reaction, the one-way valve 222 will close when the fluid in the mixing chamber 224 pushes the one-way valve 222 back.

[0081] Figure 6 The stage is depicted at which all, or at least substantially all, of the chemicals have been mixed, reacted, and released as fracturing energy 234 through pressure relief valve 208. In some embodiments, the chemical reaction releases nitrogen; however, other chemicals may be used to release different gases to suit a particular application. Typically, chamber 206 is now empty and needs to be reloaded for additional applications, which can be done at the surface after removing the tool from the wellbore or reloaded from the surface through a chemical line in fluid communication with chamber 206.

[0082] Figure 7 The interior and exterior views of chamber 206 are depicted to show pressure relief valves 208. As shown, chamber 206 includes three pressure relief valves; however, any number or configuration of pressure relief valves may be selected to suit a particular application. Pressure relief valve 208 includes an external port 221 that may be oriented to control the direction of pressure relief.

[0083] In addition to the ability to orient and rotate chamber 206, external port 221 of pressure relief valve 208 can be oriented 360 degrees to achieve more specific goals, such as those typically found in heterogeneous reservoirs and applications that require more energy and more than one valve. Specifically, external port 221 can be oriented with the same goal of providing maximum energy, such as in the case of very strong formations, where the energy required may be very large and one valve may not be sufficient to release enough energy. Figure 7 As shown, two or more valve ports 221 are adjusted in the same direction to release maximum energy at a specific target. The nozzle direction can be preset on the ground or can be directed in situ by the control system.

[0084] Figure 8 An alternative chamber 306 is depicted in which the reaction is triggered based on heat or timing, so that no piston or check valve is required in this configuration. Otherwise, chamber 306 is similar to chamber 206 in that both chamber 306 and chamber 206 include a rotating assembly 330, a centralizer 314, a reinforcing plug 326, a pressure relief valve 308, and a chemical reservoir 318. In applications where the chemical is triggered by time or heat, such as Figure 8As shown, chamber 306 uses heating fiber optic cable 312 to heat the mixture because the chemicals are already mixed and no piston or one-way valve is needed. In some embodiments, the previously described chamber 206 can be used by disabling piston 228 and storing the chemicals directly in mixing chamber 224. Pressure relief valve 308 is still used to release energy to the target. In some embodiments, fiber optic cable 312 transmits about 5 kilowatts (kW) of energy with high power loss. The loss is in the form of heating, which triggers the chemical reaction.

[0085] Fig.10 A method of operating the disclosed tool according to one or more embodiments is described. Typically, the tool is used in an existing wellbore or other open hole. Fig.10 In the method shown, two (2) tools 400 are used to perform multi-stage fracturing, where two (2) horizontal wells 440 are drilled in tight (low permeability, less than 2 millidarcy) or conventional reservoirs. The tool 400 is used to drill a wellbore or position the tool in an existing wellbore by the laser head portion of the tool 400. Once the chemical chamber 406 is positioned at the target location, the chemical can be triggered or reacted to release a gas pulse through the pressure relief valve 408, thereby forming a fracture. These different fractures are connected as a network, establishing a fracture network 436 between the formation 438 and the wellbore 440 for production.

[0086] Fig.11 A method of using a tool according to one or more embodiments is depicted, wherein the tool 500 can be used to bypass certain non-oil producing areas, such as water zones 550, faults, and high permeability channels using the previously described snake robot and acoustic sensors. The tool 500 can also be used to target pockets (sweet spots) of oil zones 552, which are similar to oil zones with high total organic carbon (TOC) in shale. In addition, fracturing can be performed in low permeability zones 554 of the formation 538, connecting the oil zones 552 so that the oil will flow through the fracture network 536 and be produced into the well by gravity.

[0087] Fig.12 Another application of the tool is depicted, wherein fracturing occurs in a Fig.11The tools shown can be applied to vertical and horizontal wells at different intensities. The tools can be used to form fractures with different half-lengths to form alternative fracture networks 636. In some embodiments, when the flow 649 is relatively high or the wellbore is significantly thinner, it is more advantageous to place longer fractures at the top (heel end) of the wellbore 640 than at the bottom (toe end). One reason is that due to fluid hydraulics, the pressure toward the top (heel end) of the wellbore 640 is higher than the bottom (toe end). For example, the heel end pressure P3 is greater than P2, and P2 is greater than the toe end pressure P1. In other words, it is more difficult to produce hydrocarbons from level 6 of flow 649 than hydrocarbons from flow levels 5 or 4, etc. In addition, the deeper the fracture reaches, the larger the effective radius and the smaller the draw down required. This will ensure a uniform sweep of the drainage area outside the near-wellbore area, thereby minimizing fingering and cone advancement toward the wellbore.

[0088] Fig.13A and 13B Depicts the current method of hydraulic fractures propagating along the maximum horizontal stress in network 736, which open against the direction of minimum horizontal stress based on the stress field around the wellbore 740 when pumping. In a horizontal well, we can place multiple of these fractures (see Fig.12 B). In some cases, fractures may not be initiated due to high fracture pressure points or deviations from the ideal vertical plane around the wellbore 740. Worse still, the fractures may not reach the optimal half length designed. If the fracture placement is successful, proppant should be introduced to keep the fracture open, which will also create greater stress and eventually close the added material. Regardless of the field stress orientation around the wellbore 740, the tools disclosed in this application and related systems and methods are able to form radial fractures that are placed in the correct settings and at the desired depth. This creates a true effective wellbore radius that will maximize the productivity of the well. In addition, rock material is removed, eliminating the need to place proppants.

[0089] The flow 749 toward the well can be expressed by Darcy's law: (where q is the flow rate, c is the conversion factor, k is the permeability, h is the height of the production zone, μ is the viscosity, and B o is the formation volume factor, P r is the reservoir pressure, P wf is the wellbore flowing pressure, r e is the reservoir extension, and r eff is the effective wellbore radius).

[0090] The effective wellbore radius is the well radius that can be recalculated from the flow of the test well. If the well is not damaged or has enhancements around the wellbore, the well radius will be equal to the actual radius. If there is damage, the well radius is less than the actual radius, and if there is enhancement, the well radius is greater than the actual radius. In the case of hydraulic fracturing, the effective wellbore radius can be calculated as: (where r weff is the effective wellbore radius, and x F is half the length of the crack).

[0091] Keeping in mind that conventional hydraulic fracturing will cause damage around the fractures created, the process is still considered successful as long as the effective radius is significantly higher than the actual radius. F Half the radial fractures should mathematically give similar results to hydraulic fracturing, but without the large amounts of water, proppant and horsepower required. From a practical standpoint, smaller radii are likely to produce similar effective radii due to the microfractures and enhancements created by this non-destructive technique.

[0092] In some embodiments of the method disclosed in the present application, drilling can be performed by using a high-power laser tool or a conventional drilling and completion tool. As previously described, the laser tool is equipped with a high-power optical fiber and a beam delivery device for drilling. If conventional drilling is used and the tool is used for fracturing, the tool can be used without high-power laser capabilities. In both cases, the tool can store and carry chemicals in a specially designed insulating chamber. When the tool is used for drilling, the tool can penetrate the formation in any direction regardless of the strength of the formation, and can deliver high-power laser energy to form a well or tunnel.

[0093] Generally, the materials of construction of downhole composite tools and related systems can be any type of material that can withstand the high temperatures, pressures, and vibrations that may be experienced in existing wellbores and can protect the system from fluids, dust, and debris. One of ordinary skill in the art will be familiar with suitable materials.

[0094] The laser generating unit can excite energy to a level higher than the sublimation point of the hydrocarbon-bearing formation, and the energy is output as the original laser beam. Those skilled in the art can determine the excitation energy of the laser beam required to sublimate the hydrocarbon-bearing formation. In some embodiments, the laser generating unit can be adjusted to excite energy to different levels according to the needs of different hydrocarbon-bearing formations. The hydrocarbon-bearing formation may include limestone, shale, sandstone or other rock types commonly found in hydrocarbon-bearing formations. The emitted laser beam can penetrate wellbore casing, cement and hydrocarbon-bearing formations to form, for example, a well or tunnel.

[0095] The laser generating unit may be any type of laser unit capable of generating a high power laser beam that can be conducted through a fiber optic cable, such as a laser of ytterbium, erbium, neodymium, dysprosium, praseodymium, and thulium ions. In some embodiments, the laser generating unit comprises, for example, a 5.34 kW ytterbium doped multi-clad fiber laser. In some embodiments, the laser generating unit may be any type of laser capable of delivering a laser beam with minimal loss. A person skilled in the art may determine the wavelength of the laser generating unit based on the need to penetrate the hydrocarbon-bearing formation.

[0096] The composite tool may also include a motion system that lowers the tool to the desired height within the wellbore. In various embodiments, the motion system may be in electrical or optical communication with the laser generation unit; such that the motion system may communicate its height within the wellbore to the laser generation unit and may receive a height target from the laser generation unit. The motion system may move the tool up or down to the desired height and may include, for example, a hydraulic system, an electrical system, or a motor operating system to drive the tool to the desired position. In some embodiments, a control device for the motion system is included as part of the laser generation unit. In some embodiments, the laser generation unit may be programmed to control the placement of the tool based only on a specified height target and position target. In some embodiments, the tool may receive a height target from the laser generation unit and move to the height target.

[0097] At least portions of the tools, systems, methods, and various modifications thereof may be at least partially controlled by a computer program product, such as a computer program tangibly embodied in one or more information carriers, such as a computer program embodied in one or more tangible machine-readable storage media, for execution by or to control the operation of a data processing device, such as a programmable processor, a computer, or multiple computers, as is familiar to one of ordinary skill in the art.

[0098] It is contemplated that the systems, apparatus, methods, and processes of the present application cover variations and adaptations developed using the information of the embodiments described in the accompanying description.Adaptation or modification of the methods and processes described in this specification may be performed by a person of ordinary skill in the relevant art.

[0099] Throughout the specification, where compositions, compounds, or products are described as having or including specific components, or where processes and methods are described as having or including specific steps, it is contemplated that there are additionally articles, devices, and systems of the present application consisting essentially of or consisting of the recited components, and that there are processes and methods according to the present application consisting essentially of or consisting of the recited process steps.

[0100] It should be understood that the order of steps or the order in which certain actions are performed is not important, as long as the method described is still operable. In addition, two or more steps or actions can be performed simultaneously.

Claims

1. A method of stimulating a hydrocarbon-bearing formation using a tool, characterized in that: The method comprises the following steps: positioning a composite tool within a wellbore in a subterranean formation, wherein the composite tool comprises one or more chemical chambers, the chemical chambers comprising a storage device for storing at least one chemical, a delivery device for delivering a reaction product of the at least one chemical, and a laser head; transmitting, through one or more optical transmission media, an original laser beam generated by a laser generating unit at a starting point of an optical path, the optical path including the one or more optical transmission media; orienting a laser head of the composite tool within a wellbore; delivering the raw laser beam to an optical assembly disposed in the laser head, wherein the optical assembly includes one or more lenses, one or more prisms, and a collimator; manipulating the original laser beam using the optical assembly to produce an output laser beam; delivering the output laser beam to a formation; orienting a delivery device of the composite tool within a wellbore; triggering a chemical reaction within the composite tool to generate energy; and delivering said energy to the wellbore, Wherein the chemical reaction is triggered by at least one of heating or mixing the at least one chemical.

2. The method according to claim 1, characterized in that The chemical reaction is triggered by heating the at least one chemical.

3. The method according to claim 1, characterized in that The chemical reaction is triggered by mixing the at least one chemical.

4. The method according to claim 3, characterized in that The method comprises: Storing two or more chemicals in two containers for mixing; advancing pistons within the two containers to discharge the chemicals from the two containers into the mixing chamber; and The chemical is delivered to the mixing chamber using a one-way valve disposed at the distal end of each of the two containers.

5. The method according to claim 1, characterized in that The method includes using a rotation assembly to orient the chemical compartment and delivery device toward a desired destination.

6. The method according to claim 1, characterized in that The laser beam is directed relative to the wellbore by moving a housing that houses at least a portion of the optical assembly.

7. The method according to claim 1, characterized in that The laser head is directed within the wellbore by using a plurality of nozzles disposed around the periphery of the laser head.

8. The method according to claim 7, characterized in that The method includes rotating or pivoting the nozzle relative to the laser head to provide at least forward motion, reverse motion, rotational motion, or a combination thereof to the laser head.

9. The method according to claim 1, characterized in that: The method includes delivering a flushing fluid emitted from a flushing assembly disposed at least partially within or adjacent to the laser head to an area proximate the output laser beam.

10. The method according to claim 1, characterized in that Positioning the composite tool within the wellbore is accomplished via the articulated arm and the sensor.

11. The method according to claim 10, characterized in that The step of positioning the composite tool within the wellbore is accomplished via an articulated arm comprising a snake-like robot having motion means for manipulating the tool within the wellbore.

12. The method according to claim 1, characterized in that The method includes using a rotation assembly to rotate at least one of the laser head or the chemical compartment relative to a central axis of the tool.

13. The method according to claim 2, wherein: The at least one chemical includes ammonium nitrite or sodium azide.

14. The method according to claim 3, wherein: The at least one chemical includes sodium nitrite and sulfamic acid, or sodium bicarbonate and acetic acid.

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