• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
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    • 专利摘要:
    A drill bit (114) for electrocoupling is disclosed. A drill bit (114) by electrocoupling may comprise a bit body; an electrode coupled to a power source and the bit body, the electrode having a distal portion for cooperating with a surface of a wellbore (116); a ground ring coupled to the bit body proximate the electrode and having a distal portion for cooperating with the surface of the well, the electrode and the grounding ring positioned relative to each other so that an electric field produced by a voltage applied between the ground ring and the electrode is reinforced at a portion of the electrode near the distal portion of the electrode and at a portion of the ring mass near the distal portion of the ground ring; and an insulator coupled to the bit body between the electrode and the ground ring.
    公开号:FR3061925A1
    申请号:FR1850221
    申请日:2018-01-11
    公开日:2018-07-20
    发明作者:William M. Moeny
    申请人:Chevron USA Inc；Halliburton Energy Services Inc；SDG LLC；
    IPC主号:
    专利说明:

    Owner (s): HALLIBURTON ENERGY SERVICES, INC., CHEVRON U.S.A. INC., SDG LLC.
    O Extension request (s):
    Agent (s):
    GEVERS & ORES Public limited company.
    ® DRILL BIT FOR ELECTROCONCASSAGE WELLBORE DRILLING.
    FR 3,061,925 - A1 (57) a drill bit (114) for drilling by electric crushing is disclosed. An electric drill bit (114) may include a bit body; an electrode coupled to a power source and the drill bit body, the electrode having a distal portion for cooperating with a surface of a wellbore (116); a ground ring coupled to the drill bit body near the electrode and comprising a distal part intended to cooperate with the surface of the well, the electrode and the ground ring positioned relative to each other so that '' an electric field produced by a voltage applied between the ground ring and the electrode is reinforced at a part of the electrode near the distal part of the electrode and at a part of the ring mass near the distal part of the mass ring; and an insulator coupled to the drill bit body between the electrode and the ground ring.

    i
    DRILL BIT FOR ELECTRICAL CRUSHING OF DOWNHOLE
    TECHNICAL AREA
    The present disclosure generally relates to drilling by downhole electrocrushing and, more particularly, the drill bits used in drilling by downhole electrocrassing.
    CONTEXT
    Electro-crushing drilling uses pulsed energy technology to dig a borehole in a rock formation. Pulsed energy technology repeatedly applies a high electrical potential through the electrodes of an electric drill bit, ultimately resulting in fracture of the surrounding rock. The fractured rock is removed from the drill bit by drilling fluid and the drill bit advances to the bottom of the well.
    BRIEF DESCRIPTION OF THE FIGURES
    For a more complete understanding of the present disclosure and of its characteristics and advantages, reference is now made to the following description taken in association with the attached figures, in which:
    Figure 1 is an elevational view of an exemplary downhole electrocompassing drilling system used in a downhole environment;
    FIG. 2 is a perspective view of examples of components of a downhole module for a downhole electro-crushing drilling system;
    FIG. 3A is a perspective view of an example of an electrode for a drill bit by downhole electrocompassing;
    Figure 3B is a cross-sectional view of the electrode illustrated in Figure 3A;
    FIG. 4A is a perspective view of an example of an electrode for a drill bit by downhole electrocompassing;
    Figure 4B is a cross-sectional view of the electrode illustrated in Figure 4A;
    FIG. 5A is a perspective view of an example of an electrode for a drill bit by downhole electrocompassing;
    Figure 5B is a cross-sectional view of the electrode illustrated in Figure 5 A;
    Figure 5C is a cross-sectional view of an alternative design of the electrode illustrated in Figure 5A;
    FIG. 6A is a perspective view of an example of a ground ring for a drill bit by electrocompassing a well bottom;
    Figure 6B is a cross-sectional view of a ground ring illustrated in Figure 6A;
    FIG. 7 is a perspective view of a drill bit by electric crushing comprising multiple electrodes and a ground ring;
    FIG. 8 is a perspective view of a drill bit by electric crushing comprising multiple electrodes placed in multiple lines with an outer ground ring and an intermediate ground ring;
    FIG. 9 is a perspective view of an electrocrassing drill bit comprising multiple electrodes, an external ground ring and an intermediate ground ring passing through the external ground ring to divide the drill bit into three regions;
    FIG. 10 is a perspective view of an electrocrassing drill bit comprising multiple electrodes, an outer ground ring and an intermediate ground ring passing through the outer ground ring to divide the electrocrassing drill bit into nine regions;
    Fig. 11 is a perspective view of an electrocrassing drill bit comprising multiple electrodes located within openings in a ground ring structure;
    FIG. 12 is a perspective view of a drill bit by electric crushing comprising multiple electrodes placed in lines, a central electrode and a ground ring; and
    Figure 13 is a flow diagram of an exemplary method for digging a wellbore.
    DETAILED DESCRIPTION
    Electro-crushing drilling can be used to form boreholes in underground rock formations to recover hydrocarbons, such as oil and gas, from these formations. Electro-crushing drilling uses pulsed energy technology to repeatedly split the rock formation by repeatedly delivering high energy electrical pulses to the rock formation. A drill bit used for electrocompass drilling includes an electrode and a ground ring coupled to a power source. The electrode and ground ring have contours designed to enhance, focus, or otherwise manage the electric field surrounding the drill bit. The electrode and ground ring have openings and fluid flow openings to facilitate the flow of drilling fluid by electrocompassing into and out of the drilling field. During a drilling operation, the electric field surrounding the drill bit is such that an arc is formed and covers the electrode and the ground ring and penetrates into the rock formation. Electrushing drilling fluid isolates the components of the drill bit and removes rock cuttings from the drilling field. Thus, an electric crush drill bit designed in accordance with the present disclosure can provide more effective drilling and removal of spoil during the drilling operation.
    There are several ways to implement the electric drill bits in a downhole pulsed energy electric crush system. Thus, the embodiments of the present disclosure and its advantages are better understood with reference to Figures 1 and 7, in which similar figures are used to identify corresponding parts.
    FIG. 1 is an elevation view of an example of an electric crushing drilling system used for digging a wellbore in an underground formation. Although Figure 1 illustrates onshore equipment, downhole tools including the teachings of this disclosure can be used satisfactorily with equipment located on offshore platforms, drilling vessels, semi-submersibles and barges drilling (not expressly illustrated). Furthermore, while the wellbore 116 is illustrated as being a generally vertical wellbore, the wellbore 116 may be of any orientation including a generally horizontal, multilateral or directional orientation.
    The drilling system 100 comprises a drilling platform 102 which supports a derrick 104 having a movable block 106 making it possible to raise and lower a drilling column 108. The drilling system 100 also comprises a pump 124 which circulates a drilling fluid. electric crushing drilling 122 through a supply pipe to the drill string 110, which in turn transports the drilling fluid by electric crushing 122 to the bottom of the well through internal channels of the drill string 108 and through one or more several orifices in the electric drill bit 114. The electric drilling fluid 122 then returns to the surface through the ring 126 formed between the drill string 108 and the side walls of the borehole 116. The fractured portions of the formation is transported to the surface by the drilling fluid by electric crushing 122 to remove these fractured parts from the wellbore 116.
    The electric drill bit 114 is attached to the distal end of the drill string 108. In some embodiments, the current to the electric drill bit 114 can be supplied from the surface. For example, a generator 140 can generate an electric current and supply this current to the current conditioning unit 142. The current conditioning unit 142 can then transmit the electrical energy to the bottom of the well through a surface cable 143 and an underground cable (not expressly illustrated in FIG. 1) contained in the drill string 108 or fixed on the side of the drill string 108. A pulse generation circuit inside the downhole module (BHA) 128 can receive electrical energy from the current conditioning unit 142, and can generate high energy pulses to drive the electric drill bit 114.
    The pulse generation circuit inside the BHA 128 can be used to repeatedly apply a high electrical potential, e.g., up to or exceeding 150 kV, through the electrodes of the electric drill bit 114 Each application of electrical potential can be called a pulse. When the electric potential across the electrodes of the electric drill bit 114 is sufficiently increased during a pulse to generate a sufficiently high electric field, an electric arc is formed through a rock formation at the bottom of the borehole 116. The arc temporarily forms an electrical coupling between the electrodes of the electric drill bit 114, allowing an electric current to pass through the ARC inside part of the rock formation at the bottom of the well 116 The ARC greatly increases the temperature and pressure of the part of the rock formation through which the ARC flows and the formation and surrounding materials. The temperature and pressure are high enough to break the rock itself into small pieces or cuttings. This fractured rock is removed, generally by the electro-crushing drilling fluid 122, which moves the fractured rock away from the electrodes and upwards.
    As the electric drill bit 114 repeatedly fractures the rock formation and the electric drill fluid 122 moves the fractured rock to the surface, the wellbore 116, which penetrates various underground rock formations 118, is created. The wellbore 116 can be any hole dug in an underground formation or a series of underground formations for the purposes of exploration or extraction of natural resources such as, for example, hydrocarbons, or for the purposes of injection. fluids such as water, wastewater, brine, or water mixed with other fluids. In addition, the borehole 116 can be any hole dug in an underground formation or a series of underground formations for the purpose of producing geothermal energy.
    Although the drilling system 100 is described herein as using an electric crush drill bit 114, the drilling system 100 can also use an electro-hydraulic drill bit. An electrohydraulic drill bit may have one or more electrodes and a ground ring similar to the electro-crushing drill bit 114. But, rather than generating an arc in the rock, an electrohydraulic drill bit applies a high electrical potential through the or the electrodes and the ground ring to form an arc through the drilling fluid near the bottom of the borehole 116. The high temperature of the arc vaporizes the part of the fluid immediately surrounding the arc, which generates in turn a high energy shock wave in the remaining fluid. One or more electrodes of the electrohydraulic drill bit may be oriented so that the shock wave generated by the arc is transmitted down the borehole 116. When the shock wave strikes and bounces on the rock at the bottom of borehole 116, the rock fractures. As a result, the drilling system 100 can use pulsed power technology with an electro-hydraulic drill bit to drill the wellbore 116 into an underground formation 118 in a similar manner to that with the electrocompassing drill bit 114.
    FIG. 2 is a perspective view of examples of components of the downhole module for a downhole electrocompassing drilling system 100. The downhole module (BHA) 128 can include a pulsed power tool 230. The BHA 128 can also include an electric drill bit 114. In the context of the present disclosure, the electric drill bit 114 can be integrated to BHA 128, or may be a separate component that is coupled to BHA 128.
    The impulse power tool 230 can be coupled to provide pulsed electrical energy to the drill bit by electrocompassing 114. The impulse power tool 230 receives electric current from a power source via cable 220. By example, the pulsed electric tool 230 can receive an electric current via the cable 220 from a surface power source as described above with reference to FIG. 1, or from a source of supply located at the bottom of the well as a generator supplied by a mud turbine. The pulsed power tool 230 can also receive electrical current through a combination of a power source on the surface and a power source located at the bottom of the well. The pulse electric tool 230 transforms the electric current from the power source into high energy electric pulses which are applied through the electrode 208 and the ground ring 250 of the drill bit by electrocassing 114.
    With reference to FIG. 1 and to FIG. 2, the drilling fluid by electric crushing 122 can leave the drilling column 108 via the opening 209 surrounding the electrode 208. The flow of drilling fluid by electrocasting 122 from of the opening 209 allows the electrode 208 to be isolated by the drilling fluid by electric crushing. While an electrode 208 is shown in FIG. 2, the electric drill bit 114 may include multiple electrodes 208. The electric drill bit 114 may include a solid insulator 210 surrounding the electrode 208 and one or more orifices (not explicitly illustrated in FIGS. 1 or 2) on the face of the electric drill bit 114 through which the electric drilling fluid 122 leaves the drilling column 108. Such orifices can be simple holes, or can be nozzles or other characteristics formed. Since fines are generally not generated during electrocompassing drilling, unlike mechanical drilling, electrocompassing drilling fluid 122 may not exit the drill bit at a pressure as high as the drilling fluid in mechanical drilling . Therefore, nozzles and other features used to increase the pressure of the drilling fluid would not be necessary. However, nozzles or other features for increasing the pressure of the drilling fluid by electric crushing 122 or for orienting the drilling fluid by electric crushing may be included for certain uses. In addition, the shape of the solid insulator 210 can be chosen to improve the flow of electric drilling fluid 122 around the components of the electric drilling bit 114.
    The electro-crushing drilling fluid 122 is generally circulated through the drilling system 100 at a rate sufficient to remove fractured rock from the vicinity of the electrocasting drilling bit 114. In addition, the electrocasting drilling fluid 122 can be under sufficient pressure at a location in wellbore 116, in particular a location near a hydrocarbon, gas, water or other deposit, to prevent a blowout.
    The electric drill bit 114 may include the drill bit body 255, the electrode 208, the ground ring 250 and the solid insulation 210. The electrode 208 may be placed approximately in the center of the electric drill bit 114. The distance between the electrode 208 and the ground ring 250 can be at least about 0.4 inch (about 1 cm) and at most about 4 inches (about 10 cm). The distance between the electrode 208 and the ground ring 250 can be based on the parameters of the electrocassassing drilling operation. For example, if the distance between the electrode 208 and the ground ring 250 is too small, the electrocompassing drilling fluid 122 may degrade and the arc between the electrode 208 and the ground ring 250 may not cross the rock. However, if the distance between the electrode 208 and the ground ring 250 is too great, the electric drill bit 114 may not have adequate tension to arc through the rock. For example, the distance between the electrode 208 and the ground ring 250 can be at least 0.4 inch (approximately 1 cm), at least 1 inch (approximately 2.5 cm), at least 1.5 inch (about 3.8 cm) or at least 2 inches (about 5 cm). The distance between the electrode 208 and the ground ring 250 can be based on the diameter of the electric drill bit 114. The distance between the electrode 208 and the ground ring 250 can be generally symmetrical or can be asymmetrical so that the electric field surrounding the electric drill bit has a symmetrical or asymmetrical shape. The distance between the electrode 208 and the ground ring 250 allows the drilling fluid by electric crushing 122 to flow between the electrode 208 and the ground ring 250 to eliminate the vaporization bubbles from the drilling area. If the drilling system 100 encounters spray bubbles in the electrocassassing drilling fluid 122 near the electrocushing drill bit 114, the vaporization bubbles can have deleterious effects. For example, vaporization bubbles near the electrode 208 can impede the formation of the arc in the rock. The electro-crushing drilling fluid 122 can be circulated at a flow rate also sufficient to eliminate the vaporization bubbles in the vicinity of the electrocrushing drill bit 114.
    The electrode 208 has three sections: the face 216, the body 217 and the rod 218. The face 216 is a distal part of the electrode 208 in contact with the rock during a drilling operation by electric crushing. For example, the face 216 can come into contact with part of the wellbore, such as the wellbore 116 illustrated in FIG. 1. The body 217 couples the face 216 to the rod 218. The rod 218 couples the electrode 208 to the electric drill bit 114. The electrode 208 may have any suitable diameter depending on the drilling operation. For example, the electrode 208 may have a diameter between about two and about ten inches (between about 5 and 25 cm). In some embodiments, the electrode 208 may have a diameter of less than two inches (about 2.5 cm). The diameter of the electrode may be based on the diameter of the electric drill bit 114 and the distance between the electrode 208 and the ground ring 250, as described above.
    The geometry of the electrode 208 affects the electric field surrounding the electric drill bit 114 during the electric drill. For example, the geometry of the electrode 208 can be designed to result in an improved electric field surrounding the electrode 208 so that the arcs strike at the level of the electrode 208 and end on the ground ring 250, or vice versa, so that the arc strikes at the ground ring 250 and ends at the electrode 208. The electric field surrounding the electrode 208 can be designed so that most of the arcs s initiating between the electrode 208 and the ground ring 250 do so by a path or a multitude of paths leading to more efficient rock removal, eg, a path or paths through the rock. In the same way, the electric field surrounding the electrode 208 can be designed so as to minimize the arcs striking between the electrode 208 and the ground ring 250 which do so by a path or a multitude of paths which cause a less effective rock removal, e.g., one or more shortcut paths through the drilling fluid without entering the rock. For example, the face 216 of the electrode 208 can be in contact with a surface of the wellbore and a distal part of the ground ring 250 can also be in contact with the surface of the wellbore. The electric field can be designed so that the electric field is improved at a part of the electrode 208 near the face 216 and on a part of the ground ring 250 near the distal part of the ground ring 250. An improved electric field in a region surrounding the drill bit by electrocompassing 114 can cause increased electrical flow in that region. For example, the electric field E s near a conductive structure of specific shape will be greater than the average macroscopic electric field created by the voltage applied to the average spacing E app n qued by the field amplification factor, γ, defined by the equation below:
    E s
    Y = F ----‘- 'applied
    The geometry of the electrode 208 includes the profile of the face 216, the shape of the body 217 and the contours of the transitions between the face 216, the body 217 and the rod 218. For example, the face 216 can have a flat profile, a concave profile or a convex profile. The profile can be based on the design of the electric field surrounding the electric drill bit. The body 217 can have a generally conical, cylindrical, rectangular, polyhedral, teardrop, rod or any other suitable shape. The transitions between the face 216 and the body 217 can be profiled to give electric field conditions which are either favorable or unfavorable for the initiation or the termination of the arc. For example, the transition between the face 216 and the body 217 may have a pronounced radius of curvature, such that the electric field conditions are favorable for an arc to start and / or end at the transition between the face 216 and the body 217. On the other hand, the transition between the body 217 and the rod 218 may have a less pronounced radius of curvature so that the conditions are not favorable for striking and / or arcing termination at the level of the transition between the body 217 and the rod 218. A radius of curvature of a transition is the radius of a circle of which the arc of the transition is a part. For example, a pronounced radius of curvature can be a radius greater than 0.01 inch (approximately 250 µm), and sometimes in the range of approximately 0.05 to approximately 0.15 inch (approximately 1 to 3.8 mm), such as about 0.094 inch (about 2.4 mm), and a less pronounced radius of curvature can be a radius in the range of about 0.15 to about 1.0 inch (about 3.8 mm to 2.5 cm), such as about 0.25 inch (about 6 mm), about 0.5 inch (about 1.3 cm), about 0.75 inch (about 1.9 cm) , or about 1.0 inch (about 2.5 cm). The ratio of the less pronounced radius of curvature to the pronounced radius of curvature can be about 2: 1 or more, and can be up to 5: 1, 10: 1 or significantly greater than 10: 1. pronounced can be determined based on the geometry of the surrounding structures on the electric drill bit 114 and the shape of the electric field for a given drill operation. For example, the electric fields on the electrode 208 can be a function of the geometry of the ground ring 250 and the geometry and the material of the insulator 210. For example, the radius of the edge of the electrode 208 and the The shape of the electrode 208 can affect the interaction of the electric drill bit 114 with the rock. In addition, the structure of the ground ring 250 can be adjusted to change the distribution of the electric field on the electrode 208. In addition, the material used to form the insulator 210 and the configuration of the insulator 210 can be adjusted. to change the electric field on electrode 208. In some examples, the dielectric constant of the drilling fluid by electrocompassing and the geometry of rock fragments and the wellbore during the drilling process can affect the instantaneous distribution of the electric field on electrode 208. The transitions are illustrated in more detail in Figures 3A-5B. The electrode 208 can be any of the electrodes illustrated in Figures 3A-5B.
    The geometry of the electrocompassing drill bit 114, and specifically certain dimensions between the electrode 208 and the ground ring 250, can be designed to maximize the appearance of arc paths between the electrode and the ground ring which pass through the rock, ίο and / or to minimize the shortening paths taken by the arcs between the electrode and the ground ring. The body 217, or the body 217 in association with the rod 218, can be formed to give a first minimum distance between the electrode 208 and the ground ring 250, a substantial part of the conductive surface of the electrode being in the axial direction, perpendicular to face 216, being at a greater distance from the ground ring 250. The first minimum distance may be a distance less than the average distance between the electrode 208 and the ground ring 250. The first distance minimum can lead to an improvement or a relative concentration of the electric field at the perimeter of the face 216 compared to the rest of the axial extent of the electrode 208, for example, such that the first minimum distance is at least less than d '' about 15% at the average distance between the electrode 208 and the ground ring 250, at least about 25% less than the average distance between the electrode 208 and the ground ring 250, or at least about 50% less than the average distance between the electrode 208 and the ground ring 250. A ground ring of conical shape as illustrated in FIG. 2 can reach this criterion, as well as a half -sphere or certain other geometries. For example, in FIG. 2, the first minimum distance can be the distance between the perimeter of the face 216 and the ground ring 250 while the average distance between the electrode 308 and the ground ring 250 is calculated including the distance between the body 217 and the ground ring 250 and the rod 218 and the ground ring 250. The first minimum distance may be such that the electric field is improved or concentrated at a part of the electrode 208 near the face 216 and on a part of the ground ring 250 near the distal part of the ground ring 250.
    Ground ring 250 can function as an electrode and provide a location on the electric drill bit where an arc can strike and / or end. Ground ring 250 also provides one or more fluid flow ports 260 such that electrocassassing drilling fluids flow through fluid flow ports 260 away from fractured rocks and vaporization bubbles from the drilling area. In addition, the ground ring 250 provides structural support for the electric drill bit 114 to support the downforce caused by the weight of the electric drill components at the top of the well relative to the electric drill bit 114 , such as the drill string 108 illustrated in FIG. 1. The electric drill bit 114 may also include an additional structural component (not expressly shown) which supports the bearing force created by the weight of the drill components by electric breakage upstream of the electric drill bit 114. For example, an insulating ring or studs may be located on the electric drill bit 114 to carry some or all of the weight of the electric drill components and the weight of any or part of the drill string. As another example, a structural support member, physically separate from and connected to the ground ring electrode, can be used to support the weight of the electrocassassing drilling components and the drill string.
    FIG. 3A is a perspective view of an example of an electrode for a drill bit by downhole electrocompassing. Figure 3B is a cross-sectional view of the electrode illustrated in Figure 3A. The electrode 308 performs a similar function and has characteristics similar to those of the electrode 208 illustrated in FIG. 2.
    High energy electrical pulses from an energy source can be applied to electrode 308 to generate an arc as described in more detail in Figures 1 and 2. As described with reference to Figure 2, the contours of the transitions between the parts of the electrode 308 affect the electric field surrounding the drill bit by electric crushing. For example, the transition between the face 316 and the body 317, the edge 312, may have a pronounced radius of curvature, as described above with reference to FIG. 2, so that the electric field conditions are favorable to start and / or end an arc at the edge 312. On the other hand, the transition 314, between the body 317 and the rod 318, can have a less pronounced radius of curvature so that the electric field conditions are not favorable for striking and / or arcing termination.
    The electrode 308 may further comprise a fluid flow opening 309 extending through the rod 318 and the body 317 towards the face 316 to orient the drilling fluids by electrocasting of a drilling column, such as the column drill 108 shown in Figure 1, at the bottom of the well relative to the drill bit by electrocassassage. For example, the electric drill bit can be coupled to the drill string and the electric drill fluid can flow down the well through the drill bit, to the drill bit and come out the fluid flow opening 309. Some or all of the fluid flowing through the drill string can exit through the fluid flow opening 309. The fluid flow opening 309 can be centered on face 316, as illustrated in FIGS. 3A and 3B, or can be offset radially. The flow path may be coaxial with the electrode 308 or may be offset at an angle to the center line of the electrode 308. The fluid flow opening 309 may have a cross section designed to give a higher fluid velocity than flow through the drill string, and may include an orifice or a jet.
    On the other hand, the fluid flow opening 309 can be used to accept a bolt for fixing the electrode 308 to the internal structure of the BHA (not expressly shown) to which the electrode 308 is fixed. The electrode 308 may also include slots 319 which facilitate the flow of drilling fluids by electrocasting around the electrode 308. The presence of slots 319 can modify the direction and / or the speed of the flow of the drilling fluid by electric crushing through the drilling area. Some slots 319 may be channels on the face 316 of the electrode 308, as shown by the slot 319a of Figure 3B, which partially extends through the body 317. Other slots 319 may extend through the body 317, as shown in the slot 319b in FIG. 3B. Some or all of the slots 319 may end just before crossing with the fluid flow opening 309, as shown in Figures 3A and 3B, and some or all of the slots 319 may cross the flow opening of fluid 309. The electrode 308 may have any combination of slots 319. As shown in Figure 3A, the edge 320 of each slot 319 may have a pronounced radius of curvature, as described above with reference to the Figure 2, to create favorable conditions in the electric field for striking and / or arcing termination. The edge 320 of each slot 319 can also have an acute radius or any other radius of curvature suitable for the drilling and / or manufacturing process.
    The 308 electrode can be made from any material that can withstand the conditions in a wellbore and has sufficient conductivity to transmit thousands of amperes per pulse without structurally damaging the electrode, such as steel in the family 41 (often designated by the family 41xx, for example steel 4140), a carbon steel alloy, stainless steel, nickel-nickel alloys, copper-copper alloys, titanetitane alloys, chromium-chromium alloys, molybdenum-molybdenum alloys, doped ceramics, composite materials using a high melting point matrix material such as tungsten and a reinforcing material having high conductivity and low melting point, such as copper, brass , silver or gold, and combinations thereof. The conductivity of electrode 308 can be a function of the geometry of electrode 308 and the shape of the arc which forms between electrode 308 and the ground ring or other electrodes on the drill bit by electric crushing. For example, the minimum conductivity of the electrode 308 can be based on the voltage requirements of the electrocompassing drilling operation and such conductivities (measured at 20 ° C) can be at least about 0.5 x 10 Λ 6 1 / ohmmeter, at least about 1.0 x 10 Λ 7 1 / ohmmeter, or more. When an arc strikes or ends at electrode 308, the temperature at the initiation or termination point increases so that the temperature melts the surface of electrode 308. Arcing is often accompanied by a shock wave. When the shock wave strikes the molten surface of the electrode 308, part of the molten surface can separate from the rest of the electrode 308 and be transported upward with the drilling fluid by electrocasting. Therefore, to prevent loss of material, areas of electrode 308, e.g. edges 312 and / or 320, having electric field conditions favorable to initiation and / or termination can be coated of a metal matrix composite. The metal matrix composite can be formed from a matrix material having a high melting point and / or a high resistance to electrical erosion, such as tungsten, carbide, ceramic, compact polycrystalline diamond, fiber carbon, graphene, graphite, olivene (FEPO 4 ), carbon tubes or combinations thereof, infused with a metal having a low melting point, such as copper, gold, l , indium, or combinations thereof. For example, the metal matrix composite can be a tungsten and copper composite such as ELKONITE®, manufactured and sold by CMW Inc., Indianapolis, Indiana. The melting point of the matrix material can be higher than the melting point of the infused metal. During the initiation and / or termination of the arc, the infused metal may melt while the matrix material remains solid to keep the molten molten metal in place during the movement of the shock wave. After the temperature has decreased, the infused metal solidifies without any material loss.
    Although Figures 3A-3B illustrate a particular electrode design having a certain combination of features, the electrode 308 may use any suitable combination of features to generate an arc. Such characteristics may include any one or more of the characteristics of the electrode 408 illustrated in FIGS. 4A-4B and / or of the electrode 508 illustrated in FIGS. 5A-5B, such as one or more notches and / or a spring.
    FIG. 4A is a perspective view of an example of an electrode for a drill bit by downhole electrocompassing. Figure 4B is a cross-sectional view of the electrode illustrated in Figure 4A. The electrode 408 performs a similar function and has characteristics similar to those of the electrode 208 illustrated in FIG. 2.
    As described with reference to FIG. 2, the contours of the transitions between the parts of the electrode 308 affect the electric field surrounding the electric drill bit. For example, edge 412 may have a pronounced radius of curvature such that the conditions of the electric field are favorable for striking and / or arcing termination at edge 412. On the other hand, transition 414 may have a radius less pronounced curvature so that the electric field conditions are not favorable for arcing and / or arc termination.
    The electrode 408 can also include one or more notches 422 along the edge 412. The presence of notches 422 can modify the electric field surrounding the electrode 408 by increasing the electric field near the electrode 408. The edge 412 notches 422 may have a pronounced radius of curvature to create conditions conducive to strike and / or arc termination by providing a larger perimeter of the electrode 408 having a more pronounced radius of curvature than the perimeter of a smooth edge (as shown in Figure 3A). Although the notches 422 are shown in a U shape in Figure 4A, the notches 422 can have any suitable shape, including triangular, rectangular, polygonal, circular or any combination thereof. While the notches 422 are shown as indentations in edge 412, in some examples, edge 412 may have discontinuities that extend beyond edge 412. In addition, while electrode 408 is shown as including notches 422, all discontinuity along edge 412 can have an effect similar to that of notches 422. For example, edge 412 can be serrated or honeycombed. In addition, the discontinuities on the face 416 may also have an effect similar to the discontinuities along the edge 412. For example, the face 416 may include buttons, dimples or protuberances. The size of the discontinuities along the edge 412 can be a function of the spacing between the electrode 408 and a ground ring, the radius of the electrode 408, the type of rock drilled, the flow path of the drilling fluid. by electric crushing or any combination thereof. The discontinuities can project outward, or indent inward, from edge 412 or face 416, a distance (measured perpendicular to edge 412 or face 416) of about 0.03 inch ( about 760 µm) to about 0.12 inch (about 3 mm) or up to about 0.25 inch (about 6 mm) or more. The sum of the length of the perimeter of the discontinuities along edge 412 (i.e., the part of the perimeter interrupted by such discontinuities) can total about 5% to about 30% of the length of the perimeter, about 25 % to about 75% or more of the perimeter length. The sum of the surface of the discontinuities on face 416 (i.e., the part of the surface of the face interrupted by such discontinuities) can represent approximately 5% to approximately 30% of the surface of face 416 , about 25% to about 75% of the area, or more. The discontinuities can be distributed evenly around the perimeter of edge 412 or evenly on face 416, or can be increased or concentrated in parts of the perimeter of edge 412 (e.g., increased or concentrated in the center of each of the four quadrants) or portions of the surface of face 416 (e.g., augmented or concentrated in a band on face 416 near edge 412, or in multiple concentric bands, or augmented or concentrated in other areas in face 416) .
    The electrode 408 can be manufactured from materials similar to the materials described with respect to the electrode 308 of FIGS. 3A-3B, such as steel of family 41 (often designated family 41xx, for example steel 4140) , a carbon-steel alloy, stainless steel, nickel-nickel alloys, copper-copper alloys, titanium-titanium alloys, chromium-chromium alloys, molybdenum-molybdenum alloys, doped ceramics, and combinations of these. In addition, the zones of the electrode 408 having conditions of electric field favorable to the starting and / or to the formation of arc can be coated or fabricated of a composite with metallic matrix as described in FIGS. 3A- 3B.
    Although Figures 4A-4B illustrate a particular electrode design having a certain combination of features, the electrode 408 may use any suitable combination of features to generate an arc. Such features may include any one or more of the features of the electrode 308 shown in Figures 3A-3B and / or the electrode 508 shown in Figures 5A-5B, such as a flow orifice fluid, one or more slots and / or a spring.
    FIG. 5A is a perspective view of an example of an electrode for a drill bit by downhole electrocompassing. Figure 5B is a cross-sectional view of the electrode illustrated in Figure 5A. The electrode 508 performs a similar function and has characteristics similar to those of the electrode 208 illustrated in FIG. 2.
    As described with reference to FIG. 2, the contours of the transitions between the parts of the electrode 208 affect the electric field surrounding the electric drill bit. For example, the edge 512 may have a pronounced radius of curvature such that the conditions of the electric field at the edge 512 are favorable to the initiation and / or the termination of the arc. On the other hand, the transition 514, in which the body 517 joins the rod 518 of the electrode 508, can have a less pronounced radius of curvature so that the conditions of the electric field are not favorable to the priming and / or the ending of the arc.
    Similarly to the electrode 408 illustrated in FIGS. 4A-4B, the electrode 508 can also comprise one or more notches 522 along the edge 512. The presence of notches 522 can modify the electric field surrounding the electrode 508 by increasing the electric field near the electrode 508. The edge 512 of the notches 522 can have a pronounced radius of curvature to create conditions favorable to the initiation and / or termination of the arc by providing a larger perimeter of the electrode 508 having a radius of curvature more pronounced than the perimeter of a smooth edge (as illustrated on the electrode 308 of FIG. 3A). Although the notches 522 are shown in a U-shape in Figure 5A, the notches 522 can have any suitable shape, including triangular, rectangular, polygonal, circular or any combination thereof.
    The electrode 508 can be manufactured from materials similar to the materials described with respect to the electrode 308 of FIGS. 3A-3B, such as steel of family 41 (often designated family 41xx, for example steel 4140) , a carbon-steel alloy, stainless steel, nickel-nickel alloys, copper-copper alloys, titanium-titanium alloys, chromium-chromium alloys, molybdenum-molybdenum alloys, doped ceramics, and combinations of these. In addition, the areas of the electrode 508 having conditions of electric field favorable to the initiation and / or to the formation of arc can be coated or fabricated of a composite with metallic matrix as it is explained in the Figures 3A-3B.
    The electrode 508 may further comprise one or more slots 519 which facilitate the flow of the drilling fluid by electrocompassing around the electrode 508. Some slots 519 may be channels on the face 516 of the electrode 508, as it is illustrated by the slot 519a in Figure 5B, which partially extends through the body 517. Other slots 519 can extend through the body 517, as shown in the slot 519b in Figure 5B. The electrode 508 can have any combination of slots 519. The edge 520 of each slot 519 can have a pronounced radius of curvature to create favorable conditions in the electric field for striking and / or arcing.
    The electrode 508 may further include a biasing device which moves the electrode 508 away from the drill string and in contact with the rock through which the electric drill bit is digging. For example, as illustrated in FIG. 5, the electrode 508 comprises an internal spring 524. The spring 524 can be located in a fluid flow orifice, such as the fluid flow orifice 309 illustrated in Figure 3B, or a bolt fixing socket as described with reference to Figures 3A-3B. Spring action
    524 can then move the electrode 508 in a direction opposite to the drilling column and towards the rock so that the face 516 remains in contact with the rock during the drilling operation by electric crushing. In some electric drill bits, the spring 524 can be replaced by a piston 525 (as illustrated in FIG. 5C) and / or a magnetic device which pushes the face 516 to maintain contact with the rock. The piston 525 can be activated by the pressure of the drilling fluid by electric crushing in the drilling column. The magnetic device can be activated using the current pulses sent to the electrode 508.
    Although Figures 5A-5C illustrate a particular electrode design having a certain combination of features, the electrode 508 may use any suitable combination of features to generate an arc. Such features may include any one or more of the features of electrode 308 or electrode 408, illustrated in Figures 3A to 4B, such as a fluid flow port.
    FIG. 6A is a perspective view of an example of a ground ring for a drill bit by electrocompassing a well bottom. Figure 6B is a cross-sectional view of the grounding ring illustrated in Figure 6A. The ground ring 650 performs a similar function and has characteristics similar to the ground ring 250 illustrated in FIG. 2.
    The shape of the ground ring 650 can be selected to change the shape of the electric field surrounding the electric drill bit during electric drill. For example, the electric field surrounding the electric drill bit can be designed so that the arc strikes at one electrode and ends on the ground ring 650 or vice versa, so that the arc strikes the ground ring 650 and ends on the electrode. The electric field changes depending on the shape of the contours of the edges of the ground ring 650. For example, the well bottom edge 662 may have a pronounced radius of curvature such as the conditions of the electric field at the bottom edge 662 wells are favorable for striking and / or arcing termination. In addition, the well bottom edge 662 can be a distal part of the ground ring 650 which comes into contact with a part of the wellbore, such as the wellbore 116 illustrated in FIG. 1. The curve 665 on the internal perimeter of the ground ring 650 may have a less pronounced radius of curvature so that the electric field conditions at the level of the curve 665 are not favorable for striking and / or arcing termination. A radius of curvature of a transition is the radius of a circle of which the arc of the transition is a part. For example, a pronounced radius of curvature can be a radius in the range of about 0.05 to about 0.15 inch (from about 1 to 3.8 mm), such as about 0.094 inch (about 2.4 mm), and a less pronounced radius of curvature can be a radius in the range of about 0.20 to about 1.0 inch (from about 5 mm to 2.5 cm) or more, such as about 1.0 inch (about 2.5 cm) or more, such as about 0.25 inch (about 6 mm), about 0.5 inch (about 1.3 cm), about 0.75 inch (about 1 , 9 cm), or about 1.0 inch (about 2.5 cm). The less pronounced radius can be determined based on the geometry of the surrounding structures on the electric drill bit 114 and the shape of the electric field for a given electric drill operation. For example, the electric fields on the electrode 208 can be a function of the geometry of the ground ring 250 and the geometry and the material of the insulator 210. For example, the radius of the edge of the electrode 208 and the The shape of the electrode 208 can affect the interaction of the electric drill bit 114 with the rock. In addition, the structure of the ground ring 250 can be adjusted to change the distribution of the electric field on the electrode 208. In addition, the material used to form the insulator 210 and the configuration of the insulator 210 can be adjusted. to change the electric field on electrode 208. In some examples, the dielectric constant of the drilling fluid by electrocompassing and the geometry of rock fragments and the wellbore during the drilling process can affect the instantaneous distribution of the electric field on the electrode 208. The characteristics on the ground ring 650 having a pronounced radius of curvature may have the same pronounced radius or a pronounced radius different from the characteristics of the electrode having a pronounced radius of curvature.
    The ground ring 650 may include one or more fluid flow ports 660 on the outer perimeter of the ground ring 650 to direct the drilling fluid by electrocompassing around an electrode, out of the drilling field, and toward the top of the well to evacuate debris from the drilling field by electric crushing. The number and location of the fluid flow ports 660 can be determined based on the flow requirements of the electrocrassing drilling operation. For example, the number and / or size of the fluid flow ports 660 can be increased to provide a faster fluid flow and / or a larger fluid flow volume. The edge 668 of each fluid flow port 660 may have a less pronounced radius of curvature so that the electric field conditions at the edge 668 of each fluid flow port 660 are not favorable for priming and / or arc termination.
    Ground ring 650 can be made from any material that can withstand conditions in the wellbore and withstand the downforce of drilling components at the top of the well, such as family steel 41 (often designated family 41xx, for example steel 4140), a carbon-steel alloy, stainless steel, nickel-nickel alloys, copper-copper alloys, titanium-titanium alloys, chromium-chromium alloys, molybdenummolybdenum alloys , doped ceramics, and combinations thereof. As has been described with respect to the electrode 308, when an arc strikes or ends at the ground ring 650, the temperature at the initiation or termination point increases so that the temperature melt the surface of the ground ring 650. When the shock wave strikes the molten surface of the ground ring 650, part of the molten surface can separate from the rest of the ground ring 650 and be transported upwards of the well with the drilling fluid by electric crushing. Therefore, to prevent material loss, the areas of ground ring 650 having electric field conditions favorable to strike and / or arc termination can be coated or composed of a metal matrix composite , as described in the SASB figures.
    The ground ring 650 may further comprise threads 670 along the internal diameter of the ground ring 650. The threads 670 may cooperate with corresponding threads on a part of an electric drill bit so that the ring mass 650 can be replaced during the drilling operation by electric crushing. The ground ring 650 can be replaced if the ground ring 650 is damaged by erosion or fatigue during a drilling operation by electric crushing.
    The thickness of the wall 672 of the ground ring 650 can be based on the diameter of the ground ring 650 and / or the weight of the components of the top well of the electrocrassing drilling system which exert a bearing force on the ground ring 650. For example, the thickness of the wall 672 can range from approximately 0.25 inch to approximately 2 inches (approximately 6 mm to 5 cm). The thickness of the wall 672 can be based on the diameter of the ground ring 650 so that the thickness of the wall 672 increases as the diameter of the mass ring 650 increases. In addition, the thickness of the wall 672 can be tapered so that the thickness is the smallest at the bottom of the well edge 662 and the greatest between the curve 664 and the curve 665. For example, the wall thickness 672 can be about 0.3 inch (about 7.6 mm) at the bottom of well 662 edge and increase to about 0.8 inch (about 2 cm) between curve 664 and curve 665. Wall thickness taper 672 can provide annular clearance for the flow of drilling fluid by electrocasting to remove debris between the bottom hole module to which the drilling bit is fixed and the inner wall from the wellbore.
    The diameter 674 of the ground ring 650 can be based on the diameter of the wellbore and the annular clearance between the wellbore and the bottom hole module to which the drill bit is fixed by electric crushing. The diameter of the electrode contained in the ground ring 650 on the electric drill bit can be chosen to dig a given type of formation. For example, the diameter of the electrode can be selected to optimize the electric field surrounding the electric drill bit and provide a flow space for the electric drill fluid. The ground ring 650 may have an external diameter equal to the dimension of the wellbore to be dug by the drill bit by electrocassing or may have an external diameter slightly smaller than the dimension of the wellbore which is to be dug. For example, the external diameter of the ground ring 650 can be at least 0.03 inch (about 760 gm) or at least 0.5 inch (about 1.3 cm) smaller than the dimension of the well drilling that needs to be dug. In certain examples, the ground ring 650 may have characteristics on the internal diameter of the mass ring 650, like the curve 665, may have a less pronounced radius while characteristics on the external diameter of the mass ring 650, like curve 664, can have a pronounced diameter so that the electric drill bit creates an oversized wellbore during a drilling operation.
    During the electrocrushing drilling operation, the electrode and the ground ring 650 may have opposite polarities to create electric field conditions such that the arcs strike at the electrode and end on the ground ring or vice versa, so that the arcs strike at the ground ring 650 and end on the electrode. For example, the electrode may have a positive polarity while the ground ring 650 has a negative polarity.
    FIG. 7 is a perspective view of a drill bit by electric crushing comprising multiple electrodes and a ground ring. The electric drill bit 714 can comprise multiple electrodes 708. The electrodes 708 can be similar to the electrode 208, illustrated in FIG. 2 and can have any of the characteristics of the electrodes 308, 408 and / or 508, illustrated in Figures 3A-5B, such as notches, dimples, serrations or other discontinuities. For example, while the electrodes 708 are illustrated as a bar in Figure 7, the electrodes 708 may have a conical shape. The electrodes 708 may have different voltages applied to each electrode 708 when electrical energy is applied to the electrodes 708. For example, the ground ring 750 and the electrode 708a may be at ground potential and the electrodes 708b may have a peak voltage of 150 kV.
    The electric drill bit 714 may further include a solid insulation 710 and a ground ring 750. The solid insulation 710 may be similar to the solid insulation 210 illustrated in Figure 2. The ground ring 750 may be similar to the ground ring 250 illustrated in FIG. 2 and may have any of the characteristics of the ground ring 650 illustrated in FIGS. 6A-6B.
    The characteristics of an electric crushing drill bit described with reference to Figures 1-6B can be combined in any configuration. For example, Figure 8 is a perspective view of a drill bit by electric crushing comprising multiple electrodes placed in multiple lines with an outer ground ring and an intermediate ground ring. The electric drill bit 814 can comprise multiple electrodes 808. The electrodes 808 can be similar to the electrode 708, illustrated in FIG. 7 and can have any of the characteristics of the electrodes 308, 408 and / or 508, illustrated in Figures 3A-5B, such as notches, dimples, serrations or other discontinuities. For example, while the electrodes 708 are illustrated as a bar in Figure 7, the electrodes 808 may have a conical shape. The 808 electrodes can be formed to facilitate fluid flow, including a tapered or aerodynamic profile. The electrodes 808b can be arranged in a pattern of one or more circular rows around the central electrode 808a. The electrodes 808 may have different voltages applied to different sets of electrodes when the electrical pulse is applied to the electrodes 808. For example, the external ground ring 850b, the intermediate ground ring 850a and the central electrode 808a can be at ground potential and the electrodes 808b and 808c can have a peak voltage of around 150 kV.
    The electric drill bit 814 can also include mass rings 850a and 850b. The ground ring 850b can be similar to the ground ring 250 illustrated in FIG. 2 and can have any of the characteristics of the ground ring 650 illustrated in FIGS. 6A-6B. The ground ring 850a can have rectangular holes, circular holes or holes of other geometric shapes.
    The 814 electrocrassing drill bit may have electrically directional drilling capability. A part, for example about a third, of the electrodes 808 of Figure 8 can be electrically connected and can fire at a higher repetition rate than the other electrodes 808, eg, about two-thirds of the electrodes 808. The drill bit 814 electrocrassing drilling rig can turn to electrodes at slow repetition speed. In this way, the 814 electrocompassing drill bit can be used to electrically steer the drill bit during drilling operations by independently controlling the repetition rate of the 808 electrode groups.
    FIG. 9 is a perspective view of an electrically crushed drill bit comprising multiple electrodes, an external ground ring and an intermediate ground ring passing through the external ground ring to divide the drill bit into three regions. The electrocompassing drill bit 914 may include multiple electrodes 908. The electrodes 908 are placed in three groups within each of the three segments formed by the transverse ground ring. The electrodes 908 can be similar to the electrode 808 or 708, illustrated in FIGS. 7 and 8 and can have any of the characteristics of the electrodes 308, 408 and / or 508, illustrated in FIGS. 3A-5B, such as notches, dimples, serrations or other discontinuities. For example, while the electrodes 708 are illustrated as a bar in Figure 7, the electrodes 908 may have a conical shape. The 908 electrodes can be formed to facilitate fluid flow, including a tapered or aerodynamic profile. The electrodes 908 may have different voltages applied to different groups of electrodes when the electrical pulse is applied to the electrodes 908. For example, the external ground ring 950a and the transverse mass structure 950b may be at ground potential and the 908 electrodes can have a peak voltage of around 150 kV. While the electrodes 908 are shown in Figure 9 as placed in three segments, the electrodes 908 can be placed in more or less segments.
    The electrocompassing drill bit 914 may further comprise an external ground ring 950a and a transverse mass structure 950b. The ground ring 950 can be similar to the ground ring 250 illustrated in FIG. 2 and can have any of the characteristics of the ground ring 650 illustrated in FIGS. 6A-6B. The external mass ring 950a and the transverse mass structure 950b may have rectangular holes, circular holes or holes of other geometric shapes.
    The 914 electrocrassing drill bit may have electrically controlled directional drilling capability. A group of electrodes 908 within a segment formed by the transverse mass structure 950b can fire at a higher repetition rate than the other groups of electrodes 908. The electric drill bit 914 can rotate toward the electrodes 908 by pulling at a slow repetition speed. In this way, the 914 electrocompassing drill bit can be used to electrically steer the drill bit during drilling operations by independently controlling the repetition rate of the 908 electrode groups.
    Figure 10 is a perspective view of an electrocrassing drill bit comprising multiple electrodes, an outer ground ring and an intermediate ground ring passing through the outer ground ring to divide the electrocrassing drill bit into nine regions. Each of the nine regions surrounds the wedge-shaped electrode 1008. The electric drill bit 1014 can include multiple electrodes 1008. The electrodes 1008 can be placed in groups. For example, the electric drill bit 1014 comprises three groups of three electrodes 1008 each in each of the nine segments formed by the transverse ground ring 1050. Each of the electrodes 1008 may have the same shape or may have different shapes as shown Figure 10. In Figure 10, the electrodes 1008 are shown as wedge-shaped so that the electrodes 1008 fit into the wedge-shaped segments formed by the transverse mass structure 1050b. Furthermore, the electrodes 1008 can be elliptical in shape or a combination of curved and straight lines to fit inside the segments formed by the transverse mass structure 1050b. The electrodes 1008 may have different voltages applied to different groups of electrodes at different times to provide a drilling function. For example, the ground ring 1050a and the transverse mass structure 1050b may be at ground potential and the electrodes 1008 may have a peak voltage of about 150 kV. While Figure 10 shows a multi-electrode configuration made up of nine segments and nine electrodes 1008, the electrocompassing drill bit 1014 can have a configuration that consists of six electrodes, eight electrodes, twelve electrodes or another number of electrodes 1008 according to the parameters of the drilling operation.
    The electric drill bit 1014 can further comprise a transverse mass structure 1050b integral with or separate from the external mass ring 1050a. The external ground ring 1050a can be similar to the ground ring 250 illustrated in FIG. 2 and can have any of the characteristics of the ground ring 650 illustrated in FIGS. 6A-6B. The external ground ring 1050a and the transverse ground ring 1050b may have rectangular holes, circular holes or holes of other geometric shapes between the segments.
    The 1014 electrocrassing drill bit may have electrically directional drilling capability. A group of electrodes 1008 within a group of segments formed by the transverse mass structure 1050b can fire at a higher repetition rate than other groups of electrodes 1008. The electric drill bit 1014 can turn to electrodes 1008 by pulling at a slow repetition speed. In this way, the 1014 electrocompassing drill bit can be used to electrically steer the drill bit during drilling operations by independently controlling the repetition rate of the electrode groups 1008.
    FIG. 11 is a perspective view of an electrically crushed drill bit comprising multiple electrodes located within openings in a ground ring structure. The electrocrassing drill bit 1114 may include multiple electrodes 1108. The electrodes 1108b may each be located within an orifice in the ground ring structure 1150. Each of the electrodes 1108 may have the same shape, as the demonstrates Figure 11, or may have different shapes. The electrodes 1108 can be similar to the electrode 808 or 708, illustrated in FIGS. 7 and 8 and can have any of the characteristics of the electrodes 308, 408 and / or 508, illustrated in FIGS. 3A-5B, such as notches, dimples, serrations or other discontinuities. For example, while the electrodes 1108 are illustrated as a bar in Figure 11, the electrodes 1108 may have a conical shape. The electrodes 1108 may have different voltages applied to different groups of electrodes at different times to provide a directional drilling function. For example, the structure of the ground ring 1150 can be at ground potential and the electrodes 1108 can have a peak voltage of around 150 kV. While FIG. 11 shows a multi-electrode configuration consisting of seven electrodes 1108 inside the structure of the ground ring 1150, the electrocrassing drill bit 1114 can have a configuration which consists of four electrodes, in ten electrodes or another number of electrodes 1108 depending on the parameters of the drilling operation.
    The electric drill bit 1114 may also include a structure of the ground ring 1150 which may be flat and perpendicular to the direction of movement of the electric drill bit 1114. The structure of the ground ring 1150 may also include parts curved, as shown in Figure 11, to use the 1114 Electric Drill Bit during directional drilling.
    The 1114 electrocrassing drill bit may have an electrically controlled directional drilling capability. One or more electrodes 1108 can fire at a higher repetition rate than the other electrodes 1108. The electric drill bit 1114 can rotate towards the electrodes 1108 when firing at a slow repetition rate. In this way, the electric drill bit 1114 can be used to electrically steer the drill bit during drilling operations by independently controlling the repetition rate of the electrode groups 1108.
    FIG. 12 is a perspective view of a drill bit by electric crushing comprising multiple electrodes placed in lines, a central electrode and a ground ring. The electrocrassing drill bit 1214 can include multiple electrodes 1208b placed in line and a central electrode 1208a. The electrodes 1208 can be similar to the electrode 708, illustrated in FIG. 7 and can have any of the characteristics of the electrodes 308, 408 and / or 508, illustrated in FIGS. 3A-5B, such as notches, dimples, serrations or other discontinuities. For example, while the electrodes 1208 are illustrated as a bar in Figure 12, the electrodes 1208 may have a conical shape. The 1208 electrodes can be formed to facilitate fluid flow, including a tapered or aerodynamic profile. The electrodes 1208 may have different voltages applied to different sets of electrodes 1208. For example, the external ground ring 1250 and the central electrode 1208a may be at ground potential and the electrodes 1208b may have a peak voltage of about 150 kV.
    The electric drill bit 1214 may further include a ground ring 1250. The ground ring 1250 may be similar to the ground ring 250 illustrated in Figure 2 and may have any of the characteristics of the ground ring 650 illustrated in Figures 6A-6B. The ground ring 1250 may include one or more protrusions 1252 integrated in the ground ring 1250 as shown in FIG. 12. The protrusions 1252 may be cylindrical, as shown in FIG. 12, or square, or triangular, or any another suitable form for controlling the speed of drilling.
    The 1214 electrocrassing drill bit may have electrically directional drilling capability. One or more electrodes 1208 in Figure 12 can be electrically connected and can fire at a higher repetition rate than the other electrodes 1208. The electric drill bit 1214 can rotate towards the electrodes 1208 while firing at a slow repetition rate . In this way, the electric drill bit 1214 can be used to electrically steer the drill bit during drilling operations by independently controlling the repetition rate of the electrode groups 1208.
    Figure 13 is a flow diagram of an exemplary method for digging a wellbore. The process 1300 can begin and in step 1310, a drill bit can be placed at the bottom of the well in a wellbore. For example, the drill bit 114 can be placed at the bottom of the hole in the borehole 116 as shown in FIG. 1.
    In step 1320, electrocassassing drilling fluid can be supplied to the downhole drilling field through a fluid flow opening in the center of the electrode, with a flow of fluid on top of the electrode. For example, as described above with reference to Figure 3, an electrode may include a fluid flow opening approximately in the center of the electrode. Electrushing drilling fluid can flow from the drill string out of the fluid flow opening and into the drilling area. Once in the drilling area, the flow of the drilling fluid by electrocompassing can be oriented by one or more slots on the face of the electrode.
    In step 1330, electrical energy can be supplied to an electrode and a ground ring of the drill bit. For example, as described above with reference to FIGS. 1 and 2, a pulse generation circuit can be implemented in the pulse electrical tool 230 of FIG. 2. As described above with reference to Figure 2, the pulsed power tool 230 can receive electrical energy from a surface power source, a power source located at the bottom of the hole or a combination of power source surface feed and power source at the bottom of the hole. Electrical energy can be supplied to the pulse generator circuit in the pulse electrical tool 230. The pulse generator circuit can be coupled to an electrode (such as the electrode 208 shown in Figure 2) and a ring earth (such as earth ring 250 or 650 illustrated in Figures 2 and 6, respectively) of drill bit 114.
    In step 1340, an electric arc can be formed between the first electrode and the second electrode of the drill bit. The pulse generator circuit can be used to repeatedly apply a high electrical potential, e.g., up to 150 kV or more, across the electrode. Each application of electrical potential can be called a pulse. When the electric potential through the electrode and the ground ring is increased enough during a pulse to generate a sufficiently high electric field, an electric arc is formed through a rock formation at the bottom of the wellbore. The arc can strike at a part of the electrode having a pronounced radius of curvature and terminate on a part of the ground ring having a pronounced radius of curvature, or vice versa, so that the arc starts on a part of the ground ring having a pronounced radius of curvature and ends on a part of the electrode having a pronounced radius of curvature. The arc temporarily forms an electrical coupling between the electrode and the ground ring, allowing an electric current to flow through the arc inside part of the rock formation at the bottom of the wellbore .
    In step 1350, the rock formation at one end of the wellbore can be fractured by the electric arc. For example, as described above with reference to FIGS. 1 and 2, the arc considerably increases the temperature of the part of the rock formation through which the arc flows, as well as the formation and the surrounding materials. The temperature is high enough to vaporize water or other fluids which may touch or approach the arc and may also vaporize part of the rock formation itself. The vaporization process creates a high pressure gas which expands and, in turn, fractures the surrounding rock.
    In step 1360, the fractured rock can be removed from the end of the wellbore. For example, as described above with reference to FIG. 1, the electrocassassing drilling fluid 122 can move the fractured rock away from the electrode and up the well away from the bottom of the wellbore 116 The steps of the 1300 process can be repeated until drilling the wellbore or replacing the drill bit. Thereafter, the process 1300 can end.
    Modifications, additions or omissions can be made to the 1300 process without departing from the scope of the disclosure. For example, the order of the steps can be carried out in a different way from that described and certain steps can be carried out at the same time. In addition, each individual step may include additional steps without departing from the scope of this disclosure.
    The embodiments of the present invention may include:
    A. An electric crushing drill bit comprising a drill bit body; an electrode coupled to a power source and to the drill bit body, the electrode having a distal portion for cooperating with a surface of a wellbore; a ground ring coupled to the drill bit body near the electrode and comprising a distal part intended to cooperate with the surface of the well, the electrode and the ground ring positioned relative to each other so that '' an electric field produced by a voltage applied between the ground ring and the electrode is reinforced at a part of the electrode near the distal part of the electrode and at a part of the ring mass near the distal part of the mass ring; and an insulator coupled to the drill bit body between the electrode and the ground ring.
    B. A downhole drilling system comprising a drill string; and a drill bit coupled to the drill string and the power source. The drill bit includes a bit body; an electrode coupled to a power source and the drill bit body, the electrode having a distal portion for cooperating with a surface of the wellbore; a ground ring coupled to the drill bit body near the electrode and comprising a distal part intended to cooperate with the surface of the well, the electrode and the ground ring positioned relative to each other so that '' an electric field produced by a voltage applied between the ground ring and the electrode is reinforced at a part of the electrode near the distal part of the electrode and at a part of the ring mass near the distal part of the mass ring; and an insulator coupled to the drill bit body between the electrode and the ground ring.
    C. A method comprising placing a drill bit at the bottom of the hole in a wellbore; supporting the weight of the drill bit and a drill string with a drill string support; supplying electrical power to the drill bit; the supply of a drilling fluid by electric crushing to the drill bit; forming an electric arc between the portion of the electrode close to the distal portion of the electrode and the portion of the ground ring near the distal portion of the ground ring of the drill bit; fracturing a rock formation at one end of the wellbore with the electric arc; and removing the fractured rock from the end of the wellbore with the drilling fluid by electric crushing. The drill bit includes a bit body; an electrode coupled to a power source and to the drill bit body, the electrode having a distal portion for cooperating with a surface of a wellbore; a ground ring coupled to the drill bit body near the electrode and comprising a distal part intended to cooperate with the surface of the well, the electrode and the ground ring positioned relative to each other so that '' an electric field produced by a voltage applied between the ground ring and the electrode is reinforced at a part of the electrode near the distal part of the electrode and at a part of the ring mass near the distal part of the mass ring; and an insulator coupled to the drill bit body between the electrode and the ground ring.
    Each of embodiments A, B and C can have one or more of the following additional elements, in any combination: Element 1: in which the electrode also comprises a rod adjacent to the body and an opening extending through the rod and the body to the face of the electrode. Element 2: wherein the electrode further comprises a slot in the face of the electrode. Element 3: in which the slot is a channel in the face of the electrode. Element 4: in which the slot extends through the body of the electrode. Element 5: in which the edge of the face of the electrode includes a notch. Element 6: wherein the electrode also includes a rod adjacent to the body and a rod extending through a center of the rod toward the body of the electrode. Element 7: wherein the electrode also includes a rod; and a transition between the body and the electrode rod has a less pronounced radius of curvature. Item 8: wherein the ground ring further includes a fluid flow port. Element 9: wherein an edge of the fluid flow orifice on the ground ring has a less pronounced radius of curvature. Element 10: wherein the electrode also includes a rod; and the electrocrassing drilling fluid is supplied to the drill bit via a fluid flow opening extending through the rod to the electrode face of generally conical shape. Element 11: in which a flow of the drilling fluid by electric crushing is modified by a slot in one face of the electrode. Element 12: in which the electric arc begins on the distal part of the electrode and ends on the distal part of the ground ring. Element 13: in which the electric arc begins on the distal part of the ground ring and ends on the distal part of the electrode. Element 14: also comprising maintaining contact between the face of the electrode and the rock formation by compressing a spring extending through a center of a rod adjacent to the body of the electrode. Element 15: wherein an edge of the electrode has a first pronounced radius of curvature and the distal portion of the ground ring has a second pronounced radius of curvature, the first pronounced radius of curvature and the second pronounced radius of curvature radius between about 0.05 inch (about 1 mm) and about 0.15 inch (about 3.8 mm). Element 16: also comprising a drilling column support coupled to the drill bit body. Element 17: in which the ground ring is the support for the drill stand. Item 18: wherein the ground ring includes a projection extending from the ground ring. Element 19: wherein the ground ring includes an external ground ring and a transverse mass structure. Element 20: in which the ground ring comprises several ground rings. Element 21: wherein the electrode includes a plurality of electrodes. Element 22: wherein the plurality of electrodes is arranged in a circular pattern on the drill bit body. Element 23: in which the electrode has a shape chosen from the group consisting of a conical, cylindrical, rod, triangular, elliptical, wedge, conical and aerodynamic profile. Element 24: wherein providing electrical energy to the drill bit includes providing electrical energy to a subset of the plurality of electrodes at a higher repetition rate than another subset of the plurality of electrodes. Element 25: wherein the electrode also includes a rod adjacent to the body and a piston positioned in a center of the rod relative to the body of the electrode.
    Even though the present disclosure has been described with several embodiments, various changes and modifications may be suggested to a specialist in the field. This disclosure is intended to encompass various changes and modifications as being within the scope of the appended claims.
    权利要求:
    Claims (15)
    [1" id="c-fr-0001]
    CLAIMS:
    1. Electric drill bit (114; 714; 814; 914; 1014; 1114; 1214), comprising:
    a drill bit body (255);
    an electrode (208; 308; 408; 508; 708; 808; 908; 1008; 1108; 1208) coupled to a power source and to the drill bit body, the electrode having a distal portion for cooperating with a surface of 'a borehole (116);
    a ground ring (250; 650; 750; 950; 1050; 1150; 1250) coupled to the drill bit body near the electrode and having a distal portion intended to cooperate with the surface of the well, the electrode and the ring ground positioned relative to each other so that an electric field produced by a voltage applied between the ground ring and the electrode is increased at a part of the electrode near the part distal of the electrode and at a part of the ground ring near the distal part of the ground ring; and an insulator (210; 710) coupled to the drill bit body between the electrode and the ground ring.
    [2" id="c-fr-0002]
    2. An electric crushing drill bit (114) according to claim 1, wherein the ground ring (250; 650) also includes a fluid flow port (260; 660).
    [3" id="c-fr-0003]
    The electrocompassing drill bit (114) according to claim 2, wherein an edge (608) of the fluid flow orifice (660) on the ground ring (650) has a less pronounced radius of curvature.
    [4" id="c-fr-0004]
    4. A drill bit by electric crushing (114) according to any one of claims 1 or 2, wherein the electrode (308; 508) also comprises a slot (319; 519) in the face (316; 516) of l 'electrode.
    [5" id="c-fr-0005]
    5. An electric crushing drill bit (114) according to claim 4, wherein the slot (319b; 519b) extends through the body (317; 517) of the electrode (308; 508).
    [6" id="c-fr-0006]
    6. Electric drill bit (114) according to claim 4, wherein the edge (412; 512) of the face (416; 516) of the electrode (408; 508) comprises a notch (422; 522).
    [7" id="c-fr-0007]
    7. A drill bit by electric crushing (114) according to claim 4, the electrode (308; 408; 508) also comprises:
    a rod (318; 518) adjacent to the body (317; 517);
    an opening (309) extending through the rod and the body to the face (316; 416; 516) of the electrode, a spring (524) extending through a center of the rod towards the body of the 'electrode or a piston (525) positioned inside a center of the rod towards the body of the electrode; and possibly a transition (314; 414; 514) between the body and the rod of the electrode has a less pronounced radius of curvature.
    [8" id="c-fr-0008]
    8. An electric crushing drill bit (114) according to claim 4, wherein an edge (312; 412; 512) of the electrode (308; 408; 508) has a first pronounced radius of curvature and the distal portion of the ground ring (250) has a second pronounced radius of curvature, the first pronounced radius of curvature and the second pronounced radius of curvature have a radius between 0.05 inch (approximately 1.3 mm) and 0.15 inch (approximately 3.8 mm).
    [9" id="c-fr-0009]
    9. Electric drill bit (114; 714; 814; 914; 1014; 1114; 1214) according to claim 4, also comprising a drill stand support coupled to the bit body (255).
    [10" id="c-fr-0010]
    10. Electric drill bit (1214) according to claim 4, wherein the ground ring (1250) comprises a projection (1252) extending from the ground ring.
    [11" id="c-fr-0011]
    11. An electric crushing drill bit (914; 1014) according to claim 4, wherein the ground ring (1050) comprises an external ground ring (950a; 1050a) and a transverse mass structure (950b; 1050b).
    [12" id="c-fr-0012]
    The electrocompassing drill bit (714; 814; 1114; 1214) according to claim 4, wherein the electrode (708; 808; 1108; 1208) comprises a plurality of electrodes (708b; 808b, 808c; 1108b; 1208b) arranged in a circular pattern on the drill bit body (255).
    [13" id="c-fr-0013]
    13. Electric drill bit (114; 714; 814; 914; 1014; 1114; 1214) according to claim 4, wherein the electrode (208; 308; 408; 508; 708; 808; 908; 1008; 1108 ; 1208) has a shape chosen from the group consisting of a conical, cylindrical, rod, triangular, elliptical, wedge, conical and aerodynamic profile.
    [14" id="c-fr-0014]
    14. Downhole drilling system (100), comprising:
    a drill string (108);
    a power source; and a drill bit (114; 714; 814; 914; 1014; 1114; 1214) coupled to the drill string and the power source, the drill bit designed according to any one of claims 1 to 13.
    [15" id="c-fr-0015]
    15. Method (300) for digging a wellbore, comprising:
    placing a drill bit (114; 714; 814; 914; 1014; 1114; 1214) at the bottom of the well (1310) in a wellbore (116), the drill bit designed according to any one of Claims 1 to 13:
    supporting the weight of the drill bit and a drill string (108) with a drill string support;
    supplying electrical power to the drill bit (1330);
    supplying a drilling fluid by electric crushing (122) to the drill bit (1320);
    forming an electric arc (1340) between the portion of the electrode (208; 308; 408; 508; 708; 808; 908; 1008; 1108; 1208) near the distal portion of the electrode and the portion the ground ring (250; 650; 750; 950; 1050; 1150; 1250) close to the distal part of the ground ring of the drill bit;
    fracturing a rock formation at one end of the wellbore with the electric arc (1350); and removing fractured rock from the end of the wellbore with the drilling fluid by electric crushing (1360).
    1/14
    2/14
    3/14
    308
    4/14
    408
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    同族专利:
    公开号 | 公开日
    US10961782B2|2021-03-30|
    BR112019012395A2|2020-02-27|
    FR3061925B1|2021-01-01|
    US20190040685A1|2019-02-07|
    WO2018136033A1|2018-07-26|
    US20210079730A1|2021-03-18|
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    法律状态:
    2019-01-22| PLFP| Fee payment|Year of fee payment: 2 |
    2020-01-21| PLFP| Fee payment|Year of fee payment: 3 |
    2020-03-27| PLSC| Publication of the preliminary search report|Effective date: 20200327 |
    2021-01-29| PLFP| Fee payment|Year of fee payment: 4 |
    2022-01-19| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    IBPCT/US2017/013740|2017-01-17|
    PCT/US2017/013740|WO2018136033A1|2017-01-17|2017-01-17|Drill bit for downhole electrocrushing drilling|
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