Method and Apparatus for Completing Wells

Abstract

An apparatus for performing electrical discharge machining within a well, may include an elongated body comprising a first end and a second end and defining an interior cavity; and at least one electrode positioned within the elongated body, wherein the apparatus is configured to be connected to a power supply that enables electrical current to be supplied to the electrode to mine material from a production casing wall inside of a wellbore.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application No. 62/626,858, filed on Feb. 6, 2018, the disclosure of which is incorporated in its entirety by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

This disclosure relates to a method and apparatus for well completions and, more specifically, to the use of electrical discharge machining technology to more effectively and efficiently create apertures in a casing tubular positioned in wells.

Description of Related Art

Since the dawn of the Industrial Revolution, evolving human society has required ever-increasing amounts of energy to meet day-to-day needs. The ubiquitous use of automobiles for transportation in many developed parts of the world, the need to heat homes and power appliances, and the need to generate sufficient electricity to power cities and small towns is currently straining the world's energy resources beyond what mankind is able to produce. As a result, the energy industry is constantly looking for new ways to more efficiently and effectively harvest energy-producing natural resources to meet the ever-increasing demand.

Over the last sixty-five years, and particularly since the beginning of the twenty-first century, extracting natural gas and oil from conventional and unconventional reservoirs has become an increasingly attractive option for increasing energy supply. There are numerous methods by which natural gas and oil may be extracted from underground reservoirs. The most basic method involves drilling a well vertically into the earth where a reservoir is known to exist and using equipment and machinery well known within the industry to pump the hydrocarbon (e.g., oil or gas) out of the well and into midstream assets. But this is inefficient, so other methods are more widely utilized.

Today, the most common and well-known method of extracting natural gas and oil from underground reservoirs is hydraulic fracturing, known commonly as “fracking”. Wells used to extract hydrocarbons may be drilled vertically hundreds to thousands of feet below the land surface and may include horizontal or directional sections extending thousands of feet. Fracking creates fractures within a wellbore by pumping large quantities of fluids and proppants at high pressure down the wellbore and into a target rock formation. Hydraulic fracturing fluid commonly consists of water, proppant (such as sand, ceramic pellets or other small incompressible particles) and chemical additives that, when pumped at high pressure into the target rock formation, open and enlarge fractures within the rock formation. These fractures can extend several hundred feet away from the wellbore. The proppants help to hold open the newly created fractures.

Once the injection process is completed, the internal pressure of the rock formation causes hydrocarbons and fluid naturally occurring within the rock formation to return to the surface through the wellbore. This fluid that returns with the hydrocarbons is known as both “flowback” and “produced water” (collectively referred to hereafter as “flowback”), and may contain the injected chemicals plus naturally occurring materials such as brines, metals, radionuclides, and hydrocarbons. Flowback is typically stored on site in tanks or pits, before eventually being treated, disposed of, or recycled. In many cases, flowback is disposed of underground. When underground disposal is not possible, flowback may be reused or treated by a wastewater treatment facility and discharged to surface water.

Unfortunately, there is widespread concern that flowback produced by fracking is contaminating groundwater (particularly when flowback is disposed of by injecting it underground), presenting a potential threat both to the environment at large and to the human beings who rely on groundwater that may be contaminated for drinking water, cooking, and bathing. Some states, such as New York, have banned fracking despite being home to large natural gas reservoirs that could be accessed through fracking. These types of bans have created significant unrest among many communities who see fracking and other means of hydrocarbon harvesting as a means to better the economic conditions in areas where natural gas and oil reservoirs are located.

When a well is drilled, initially the wellbore is nothing more than a deep, cylindrical hole cut through the earth. Without fortifying the well, a drilling operation faces the risk that the well could collapse inward on itself. In order to prevent a well from collapsing inward on itself, wells are “cased.” The casing process involves inserting into the well very long, very large cylinders (typically made of solid steel). These long steel cylinders form a lining (i.e., casing) against the walls of the well. In order to keep the casing in place, liquid concrete is typically pumped into the space between the well walls and the casing. When the concrete hardens, it binds the casing to the well wall, thus fortifying the well to prevent the well from collapsing and providing the well operator with well control.

To permit oil and gas to enter a drilled and cased wellbore, completion equipment such as perforating guns and sleeves are used to create holes in the wellbore's casing. Perforating guns are devices that are commonly used within the energy industry in order to facilitate the extraction of energy resources from the ground. Because oil and natural gas reservoirs often span large horizontal distances, a single well may be permitted for many square acres or even many square miles of underground reservoir. But it is economically inefficient and often impossible in practice (due to legal hurdles, such as obtaining easements) for a drilling operation to drill multiple wells in order to access the horizontal breadth of a given oil or gas reservoir.

One method of accessing a reservoir's horizontal breadth without drilling multiple wells is to expand the subterranean portion of a well in a horizontal direction. By expanding the subterranean portion of a well in a horizontal direction, oil and gas located a horizontal distance from the location where the well was drilled can still be extracted through the well.

In order to be able to produce both conventional and unconventional reservoirs, operators need to give points of access for the hydrocarbons to enter the production casing string. This is accomplished by the use of perforating guns, sliding sleeves, burst disks, or other pieces of completion equipment. For example, perforating guns do this by allowing for controlled, targeted underground explosions. The controlled subterranean explosion, which targets a specific, prechosen depth and creates a hole in the production casing at that depth by setting off a series of shaped charges. These shaped charges pierce the production casing wall, and penetrate some distance into the outlying cement and geologic formation.

When multiple perforating guns are connected in an end-to-end manner and lowered into the same vertical hole, it is commonly known as a “string” of perforating guns. There are a variety of well-known methods in the art for lowering perforating guns into a well. When perforating guns are lowered to the desired depth, the charges are detonated.

However, perforating guns have problems. One problem is that the charges housed in perforating guns sometimes become displaced before they are detonated. This often results when one perforating gun on a string is detonated before other guns on the same string. The concussive force from the initial detonation often rattles the undetonated guns on the string, and in doing so can displace the charges therein.

Electrical discharge machining (“EDM”) is a non-traditional machining process. The EDM process consists of a succession of discharges made to take place between two conductors separated from each other by a film of non-conducting liquid, called a dielectric. During the EDM process, a series of timed electrical pulses cause a spark to “jump” from one of the conductors (the electrode) and strike the second conductor (the work piece). When the spark strikes the work piece, it removes an amount of material from the work piece. A power supply controls the timing and intensity of the electrical charges and the movement of the electrode in relation to the work piece.

More specifically, at the spot where the electric field between the electrode and work piece is strongest, electrons and positive free ions are accelerated to high velocities and rapidly form an ionized channel that conducts electricity. At this stage current can flow and the spark forms between the electrode and work piece. During this process a bubble of gas develops and its pressure rises very steadily until a plasma zone is formed. The plasma zone quickly reaches very high temperatures, in the region of 8,000 to 12,000 degrees Centigrade. This causes instantaneous local melting of a certain amount of the material at the surface of the work piece. When the current is cut off, the sudden reduction in temperature causes the bubble to implode, which projects the melted material away from the work piece, leaving a tiny crater.

EDM allows a user to achieve tighter tolerances and better finishes in a wide range of materials that are otherwise difficult or impossible to machine with traditional processes. This makes EDM especially well-suited for the machining of very small and very detailed work pieces. For example, EDM is often used in conjunction with the machining of parts for the aerospace and automotive industries, as well as surgical components.

SUMMARY OF THE INVENTION

In view of the drawbacks of fracking and perforating guns increasing the difficulty of efficiently and effectively harvesting oil and natural gas, there is a current need within the industry for a new method and apparatus of accessing oil and natural gas reserves that does not inherit the potential dangers of fracking or the drawbacks of perforating guns, but that still effectively and efficiently allow a drilling operation to access and harvest underground natural gas. Therefore, the present disclosure includes using a novel apparatus and method for incorporating EDM technology on a large scale to extract underground natural gas and oil reserves. The present disclosure provides a method and apparatus for employing EDM technology during the completion process for harvesting underground oil and natural gas. In addition, the present disclosure is able to use fresh water or brine water that has not been treated, as opposed to dielectric solution, to facilitate the EDM process. The present disclosure employs the EDM process directly through the production casing wall.

In one example of the present disclosure, an apparatus for performing electrical discharge machining within a well may include an elongated body comprising a first end and a second end and defining an interior cavity; and at least one electrode positioned within the elongated body, wherein the apparatus is configured to be connected to a power supply that enables electrical current to be supplied to the electrode to mine material from a production casing wall inside of a wellbore.

In another example of the present disclosure, the electrode may be radially adjustable relative to the elongated body. The at least one electrode may include a plurality of electrodes that are circumferentially spaced apart from one another in the elongated body. At least one centralizer may be provided within the elongated body, wherein the centralizer is configured to stabilize the elongated body within the production casing. The centralizer may be radially adjustable relative to the elongated body. The at least one centralizer may include a plurality of centralizers that are circumferentially spaced apart from one another in the elongated body. The at least one electrode may be positioned between a first centralizer and a second centralizer on the elongated body, wherein the first and second centralizers are configured to stabilize the elongated body within the production casing.

In another example of the present disclosure, a system for performing electrical discharge machining within a well may include a well completion device that may include an elongated body comprising a first end and a second end and defining an interior cavity; and at least one electrode positioned within the elongated body, a power supply operatively connected to the well completion device; and a control system operatively connected to the well completion device to operate the well completion device, wherein the apparatus is configured to be connected to a power supply that enables electrical current to be supplied to the electrode to mine material from a production casing wall inside of a wellbore.

In another example of the present disclosure, an isolation tool may be connected to the well completion device, wherein the isolation tool is configured to isolate the well completion device from debris that may fall into the wellbore. A half-moon swivel may be connected to the well completion device to stabilize the well completion device within the production casing. The electrode may be radially adjustable relative to the elongated body. At least one centralizer may be provided within the elongated body, wherein the centralizer may be configured to stabilize the elongated body within the production casing. The centralizer may be radially adjustable relative to the elongated body. The at least one electrode may be positioned between a first centralizer and a second centralizer on the elongated body, wherein the first and second centralizers may be configured to stabilize the elongated body within the production casing.

In another example of the present disclosure, a method of performing electrical discharge machining within a well may include (a) inserting a well completion device into a production casing positioned within a wellbore, the well completion tool comprising an elongated body comprising a first end and a second end and defining an interior cavity, and at least one electrode positioned within the elongated body; (b) bringing the at least one electrode adjacent an inner surface of the production casing; (c) generating an electrical spark between the at least one electrode and the inner surface of the production casing to mine material from the production casing; (d) ceasing generation of the electrical spark between the at least one electrode and the inner surface of the production casing; (e) washing the production casing with water to clean the area of the production casing that is being mined; and (f) repeating steps (c)-(e) until an aperture is created within the production casing.

In another example of the present disclosure, the water may be fresh water or brine water. Step (b) may include extending the at least one electrode from the elongated body or moving the elongated body adjacent the inner surface of the production casing. Before step (b), the method may include stabilizing the well completion device within the production casing. The well completion device may be stabilized in the production casing using at least one centralizer that radially extends from the elongated body. The method may include positioning an isolation tool on top of the well completion device to prevent debris from an opening of the wellbore from damaging the well completion device.

The present disclosure is also defined by the following clauses.

Clause 1: An apparatus for performing electrical discharge machining within a well, comprising: an elongated body comprising a first end and a second end and defining an interior cavity; and at least one electrode positioned within the elongated body, wherein the apparatus is configured to be connected to a power supply that enables electrical current to be supplied to the electrode to mine material from a production casing wall inside of a wellbore.

Clause 2: The apparatus of Clause 1, wherein the electrode is radially adjustable relative to the elongated body.

Clause 3: The apparatus of Clause 1 or 2, wherein the at least one electrode comprises a plurality of electrodes that are circumferentially spaced apart from one another in the elongated body.

Clause 4: The apparatus of any of Clauses 1-3, further comprising at least one centralizer provided within the elongated body, wherein the centralizer is configured to stabilize the elongated body within the production casing.

Clause 5: The apparatus of Clause 4, wherein the centralizer is radially adjustable relative to the elongated body.

Clause 6: The apparatus of Clause 4 or 5, wherein the at least one centralizer comprises a plurality of centralizers that are circumferentially spaced apart from one another in the elongated body.

Clause 7: The apparatus of any of Clauses 1-6, wherein the at least one electrode is positioned between a first centralizer and a second centralizer on the elongated body, wherein the first and second centralizers are configured to stabilize the elongated body within the production casing.

Clause 8: A system for performing electrical discharge machining within a well, comprising: a well completion device, comprising: an elongated body comprising a first end and a second end and defining an interior cavity; and at least one electrode positioned within the elongated body, a power supply operatively connected to the well completion device; and a control system operatively connected to the well completion device to operate the well completion device, wherein the apparatus is configured to be connected to a power supply that enables electrical current to be supplied to the electrode to mine material from a production casing wall inside of a wellbore.

Clause 9: The system of Clause 8, further comprising an isolation tool connected to the well completion device, wherein the isolation tool is configured to isolate the well completion device from debris that may fall into the wellbore.

Clause 10: The system of Clause 8 or 9, further comprising a half-moon swivel connected to the well completion device to stabilize the well completion device within the production casing.

Clause 11: The system of any of Clauses 8-10, wherein the electrode is radially adjustable relative to the elongated body.

Clause 12: The system of any of Clauses 8-11, further comprising at least one centralizer provided within the elongated body, wherein the centralizer is configured to stabilize the elongated body within the production casing.

Clause 13: The system of Clause 12, wherein the centralizer is radially adjustable relative to the elongated body.

Clause 14: The system of any of Clauses 8-13, wherein the at least one electrode is positioned between a first centralizer and a second centralizer on the elongated body, wherein the first and second centralizers are configured to stabilize the elongated body within the production casing.

Clause 15: A method of performing electrical discharge machining within a well, comprising: (a) inserting a well completion device into a production casing positioned within a wellbore, the well completion tool comprising an elongated body comprising a first end and a second end and defining an interior cavity, and at least one electrode positioned within the elongated body; (b) bringing the at least one electrode adjacent an inner surface of the production casing; (c) generating an electrical spark between the at least one electrode and the inner surface of the production casing to mine material from the production casing; (d) ceasing generation of the electrical spark between the at least one electrode and the inner surface of the production casing; (e) washing the production casing with water to clean the area of the production casing that is being mined; and (f) repeating steps (c)-(e) until an aperture is created within the production casing.

Clause 16: The method of Clause 15, wherein the water is fresh water or brine water.

Clause 17: The method of Clause 15 or 16, wherein step (b) comprises extending the at least one electrode from the elongated body or moving the elongated body adjacent the inner surface of the production casing.

Clause 18: The method of any of Clauses 15-17, further comprising, before step (b), stabilizing the well completion device within the production casing.

Clause 19: The method of Clause 18, wherein the well completion device is stabilized in the production casing using at least one centralizer that radially extends from the elongated body.

Clause 20: The method of any of Clauses 15-19, further comprising positioning an isolation tool on top of the well completion device to prevent debris from an opening of the wellbore from damaging the well completion device.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings included herewith are not intended to in any way limit the scope of the invention disclosed herein. The drawings are merely included to clarify and exemplify the invention as disclosed and claimed herein.

FIG. 1 is a perspective view of a well completion device according to one example of the present disclosure;

FIG. 2 is another perspective view of the well completion device shown in FIG. 1;

FIG. 3 is a side view of the well completion device shown in FIG. 1;

FIG. 4 is a cross-sectional view of the well completion device shown in FIG. 1;

FIG. 5 is a schematic illustration of a well completion system including the well completion device shown in FIG. 1;

FIG. 6 is a perspective view of an electrode arrangement provided in the well completion device shown in FIG. 1;

FIG. 7 is a perspective view of a control system/controller used in conjunction with the well completion device shown in FIG. 1; and

FIG. 8 is a perspective view of an information input panel provided on the control system/controller shown in FIG. 7.

DESCRIPTION OF THE INVENTION

The following description is provided to enable those skilled in the art to make and use the described embodiments contemplated for carrying out the invention. Various modifications, equivalents, variations, and alternatives, however, will remain readily apparent to those skilled in the art. Any and all such modifications, variations, equivalents, and alternatives are intended to fall within the spirit and scope of the present invention.

For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal”, and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.

With reference to FIGS. 1-8, the present disclosure is directed to a method and apparatus for well completions and, more specifically, to the use of electrical discharge machining (EDM) technology to more effectively and efficiently create apertures in a casing tubular positioned in wells. While the following disclosure describes a method of using EDM technology with the well completion device 2, it is also contemplated that other methods of machining may be used with the well completion device 2, including a cutting torch, combustion machining, laser machining, and mechanical machining methods.

With reference to FIGS. 1-3, the well completion device 2 includes an elongated body 4. The elongated body 4 may be made from any material that is suitable for withstanding the pressures and temperatures within underground wells and the stress that is created as a result of the EDM process. In one example of the present disclosure, the elongated body 4 is made of high-strength stainless steel. The elongated body 4 may have a generally cylindrical shape, but it is contemplated that any additional shapes may be used as needed according to the shape of the well in which the well completion device 2 is to be used. The elongated body 4 may be a monolithic structure or, in an alternative example, may be modular and include several different segments that are operatively connected or formed with one another. In one example, the separate segments may be welded together, adhesively attached to one another, and/or mechanically connected to one another to form the elongated body 4. It is also contemplated that the length of the elongated body 4 may vary based on the size of the well and the desired number of apertures that are to be formed in the production casing in the well, as will be described in greater detail below. The elongated body includes a first end 6 and an opposing second end 8. When inserted into a well, the second end 8 of the elongated body 4 is inserted into the well first such that the second end is provided at a deeper position within the well than the first end 6. The elongated body 4 defines an internal cavity that houses several different components used to operate the well completion device 2, as will be described below in greater detail.

In one example of the present disclosure, provided within or as part of the elongated body 4 is at least one electrode 10. In one example, a plurality of electrode 10 groupings are provided along a longitudinal length of the elongated body 4. In one example, at least one electrode 10 grouping is provided along the length of the elongated body 4. The electrode 10 grouping may include at least four electrodes 10 that are circumferentially spaced from one another about the longitudinal axis A of the elongated body 4. In one example, the electrodes 10 of the electrode grouping are equally spaced from one another. It is to be understood, however, that additional or less electrodes 10 may be provided in the electrode 10 grouping and the electrodes 10 may be spaced from one another at any number of different angles or spacing lengths. The electrode(s) 10 are responsible for producing an electric spark that, as explained herein, penetrates a wellbore production casing and bores fissures or holes within the well wall (horizontal or otherwise). As will be described below, in order to provide the energy necessary to produce the electric spark with the electrode(s) 10, the well completion device 2 is connected to a power supply that channels electric current from the energy source to the well completion device 2. Those with skill in the art will recognize that there are numerous energy sources that may be used to provide sufficient electricity to the well completion device 2 and any such energy source should be considered sufficient.

In one example, the electrode(s) 10 may be radially adjustable relative to the elongated body 4. For example, the electrode(s) 10 may move between a position in which the electrode(s) 10 is housed within the elongated body 4 and a position in which the electrode(s) 10 is radially extended from the elongated housing 4. The electrode(s) 10 can be extended to a plurality of different lengths from the elongated body 4 such that the well completion device 2 can be used with various production casings and wellbores of different sizes. As shown in FIG. 6, a servo motor gear 60 may be provided in the well completion device 2 that is in operative connection with a servo motor, also housed in the well completion device 2. The servo motor gear 60 may be operatively engaged with an internal gear 62 defined in the section of the elongated body 4 in which the electrode(s) 10 are positioned. During operation, as the servo motor rotates the servo motor gear 60, the internal gear 62 is rotated, thereby causing a Geneva gear (or cam surface) 64 provided in the elongated housing 4 to rotate towards and contact a bearing member 66 positioned on the electrode(s) 10. As the Geneva gear 64 is rotated, the bearing member 66 is also rotated outwardly to move the electrode(s) 10 in a radially outward direction to extend from the elongated body 4. To retract the electrode(s) 10 back into the elongated body 4, the servo motor is configured to rotate the servo motor gear 60 in an opposite direction to reverse the direction that the internal gear 62 is rotated. The electrode(s) 10 may be extended to create an electric spark with the production casing wall. In one example, the electrode(s) 10 may be rotatable about the longitudinal axis A of the elongated body 4. A controller may be operatively connected to the well completion device 2 to move the electrode(s) 10 to desired positions within the production casing to create apertures in the production casing. The controller may include specific programs so that the electrode(s) 10 are extended and rotated according to a predetermined pattern to ensure the apertures are created in the production casing at desired positions. In one example, the electrode(s) 10 may be extended at a first position to create apertures in the production casing and, subsequently, the electrode(s) 10 may be rotated to a different second position to create a second set of apertures in the production casing.

The present disclosure may also optionally include an electrode(s) 10 that rotates as part of the well completion device 2. Enabling the electrode(s) 10 to rotate enables the well completion device 2 to mine an area of the production casing, then rotate the electrode(s) 10 and mine a different area of the production casing, without having to rotate or otherwise alter the position of the elongated body 4 itself. This provides a significant advantage to users since altering the position of the entire well completion device 2 can be a time-consuming process that reduces the efficiency of an oil and gas mining operation. Increasing the efficiency of the process by including a rotating electrode(s) 10, therefore, provides a user of the present disclosure an advantage in the marketplace.

The user of the present invention can vary the size of the spark, and therefore the amount of the work piece mined away from any single spark, by varying the size of the tool.

Those with skill in the art will recognize how to manufacture the tool such that the production casing wall can be mined in an efficient, effective manner. The optimal size and intensity of the spark will vary based on the user's need.

With continued reference to FIGS. 1-3, the well completion tool 2 may also include at least one centralizer 12 provided in the elongated body 4. In another example, a plurality of centralizers 12 may be provided in a circumferential pattern around the outer surface of the elongated body 4. It is also contemplated that multiple groups of centralizers 12 may be spaced along the longitudinal length of the elongated body 4 to assist in further stabilizing the well completion device 2 within the production casing. Similar to the electrode(s) 10, the centralizer 12 is radially adjustable relative to the longitudinal axis A of the elongated body 4. In one example, the centralizer 12 can move between a first position in which the centralizer 12 is housed within the elongated housing 4 and a second position in which the centralizer 12 is extended from the elongated housing 4. The centralizer 12 can be extended to a plurality of different lengths from the elongated body 4 such that the well completion tool 2 can be used with various production casings and wellbores of different sizes. The centralizer 12 is configured to extend radially outward from the elongated housing 4 to contact the inner surface of the production casing to stabilizing the well completion device 2 therein. In one example, the centralizers 12 are configured to extend and retract from the elongated housing 4 using a similar configuration to the electrode arrangement shown in FIG. 6. The centralizer 12 is configured to press against the inner surface of the production casing so that the well completion device 2 cannot rotate or wobble within the production casing while the electrode(s) 10 create the holes in the production casing. The outer end of the centralizer 12 may include a gripping material, such as rubber, to assist in gripping the production casing. It is also contemplated that other gripping materials may be used to assist the centralizer 12 in contacting and creating a hold on the production casing.

As shown in FIG. 1, the well completion device 2 also includes a wire rope 14 operatively connected to the first end 6 of the elongated housing 4. In another example of the present disclosure, a coil tubing may be used to suspend the end of the wire rope 14 and the well completion device 2 to control the location of the well completion device 2 within the wellbore. The coil tubing and the wire rope 14 are used to move the well completion device 2 into and out of the production casing and wellbore. The well completion device 2 may also include an input cable 16 operatively connected to the first end of the elongated housing 4. As will be described in greater detail below, the input cable 16 provides power to the well completion device 2, as well as provides a communication link between the well completion device 2 and a control system/controller provided on the surface.

With reference to FIG. 4, the internal components of the well completion device 2 are briefly described and illustrated. In one example, a gate drive printed circuit board (PCB) 18, a CPU board 20, a detection/revers board 22, a power regulator board 24, and a fiber optic module 26 are provided within an interior cavity of the elongated housing 4. The well completion device 2 also includes a grip motor 28, 30 for each centralizer 12 to enable the centralizer 12 to be radially moved relative to the elongated body 4. The well completion device 2 also includes an electrode motor drive 32 used to radially move the electrode(s) 10 relative to the elongated housing 4. The fiber optic module controls the status of the devices in the ground from the ground surface (e.g., input of processing conditions, foot control, electrode up/down control, etc.). In one example, the fiber optic module 26 may be an optical communication device for sending and receiving control and feed back in real time. The CPU board 20 may be configured to send the data received from control system/controller 50 provided on the ground surface to each component of the well completion device 2. In one example, the detection/revers board 22 may be configured to check the motor current of the well completion device 2 to determine whether the foot is spreading inside of the production casing, to detect the motor current periodically, and to supply a stable discharge power. In one example, the power regulator board 24 may be configured to control a stable control power in the well completion device 2 due to voltage drops that occur when the length of the power supplied to the well completion device 2 from the ground surface is increased.

With reference to FIG. 5, a well completion system 32 is shown and described. In one example, the well completion system 32 includes the well completion device 2, a half-moon swivel 34, an isolation tool 36, and a coil tubing string 38. In one example, the well completion system 32 is positioned in a production casing 40 that has been inserted into a pre-formed wellbore 42. In one example, the production casing 40 may be a steel pipe. In another example, the production casing 40 may be a fiberglass, stainless steel, or any other type of metal pipe. It is to be understood that the production casing 40 may be any tubular or structural piece that is installed with the purpose of controlling production flow from a well. In one example, the half-moon swivel 34 is provided at a deepest or foremost position within the wellbore 42, while the coil tubing string 38 is positioned nearest the surface 44. Each of the well completion device 2, a half-moon swivel 34, an isolation tool 36, and a coil tubing string 38 may be operatively connected to one another to form the well completion system 32.

The half-moon swivel 34 may be provided to keep the well completion device 2 centralized within the production casing 40. The half-moon swivel 34 extends outwardly to make contact with the inner surface of the production casing 40 to stabilize the well completion device 2 within the interior cavity of the production casing 40. By using the half-moon swivel 34 as a stabilizing element, the well completion device 2 does not need to strain under pressure while creating apertures in the production casing 40. In one example, a shock absorbing member (not shown) may be incorporated into the half-moon swivel 34 to eliminate or minimize any vibrations in the half-moon swivel 34 and/or the well completion device 2. It is also contemplated that the half-moon swivel 34 may be provided with any circular pattern, provided the half-moon swivel 34 maintains an outer diameter that is close to the designated production casing inner diameter. The well completion system 32 may also include the isolation tool 36 to isolate the well completion device 2 from elements upstream or above the well completion device 2. The isolation tool 36 may include at least one rubber or gripping material member 46 that contacts and engages the inner surface of the production casing 40 to stabilize the well completion device 2 therein. It is also contemplated that the isolation tool 36 may operate as a sealing element during stimulation efforts in the down hole. In one example, an internal mandrel positioned within the isolation tool 36 is provided to swell the isolation tool 36 to press against the inner surface of the production casing 40. After use, the internal mandrel may be retracted to reduce the outer diameter of the isolation tool 36 to disengage from contact with the inner surface of the production casing 40. This method may be continuously used so that the isolation tool 36 may be repeatedly used within the production casing 40. The isolation tool 36 may also be provided to ensure that the working fluid used in conjunction with the electrode(s) 10 is directed to the desired area within the well bore. It is contemplated that a plurality of rubber or gripping material members may be provided on the isolation tool 36 to increase the gripping capabilities of the isolation tool 36 with the production casing 40. The coil tubing string 38 is provided to give protection to the input cable 16 to prevent the input cable 16 from being damaged by any outside elements or elements within the production casing 40.

As shown in FIG. 5, the well completion system 32 may be operatively connected to a power supply 48 and a control system/controller 50. The power supply 48 provides power to the well completion device 2 to allow the well completion device 2 to control the electrode(s) 10 and the centralizers 12. In some examples of the present disclosure, the power supply 48 may be a generator, a battery, a mud motor, natural gas fire, and any other suitable method for providing power to the well completion device 2. The control system/controller 50 is provided to control the operation of the well completion device 2. As shown in FIGS. 7 and 8, the control system/controller 50 may include a power switch 80 to control when power is applied to the well completion system 32. An emergency stop button 82 is also provided on the control system/controller 50 to allow a user to immediately power down the well completion system 32 in the event of an emergency. A bar meter 84 is provided on the control system/controller 50 to indicate to a user when the EDM processing is being implemented in the ground. An information input panel 86 is also provided on the control system/controller 50 to allow the user to operate the well completion system 32 and receive information regarding the operating performance of the well completion system 32. As shown in FIG. 8, the information input panel 86 may include EDM condition sensors 88 that indicate to a user the current operating status of the well completion device 2. A down hole counter 90 may be provided to indicate to a user the current down hole in which the well completion device 2 is operating, in the event multiple down holes have been drilled and multiple well completion devices 2 have been inserted into the different down holes. The information input panel 86 may also include buttons 92 that permit a user to change the operating condition/status of the well completion device 2. Lastly, the information input panel 86 may include an EDM processing depth indicator 94 to indicate to a user the depth at which the well completion device 2 is operating with inside of the ground.

In one example of the present disclosure, it is contemplated that multiple well completion devices 2 may be chained or connected to one another depending on the size and depth of the wellbore 42 in which the production casing 40 is positioned. Therefore, in the event the wellbore 42 is particularly deep, at least two well production devices 2 may be operatively connected to one another to create apertures along the entire length of the production casing 40 in the wellbore 42. It is also contemplated that an isolation tool 36 may be provided between each well completion device 2 on the chain of multiple well completion devices 2.

The operation and use of the well completion device 2 will now be described in greater detail. Initially, the wellbore 42 is formed in the earth and a production casing 40 is positioned therein. After the production casing 40 has been inserted into the wellbore 42, the well completion device 2 is moved into position with in an interior cavity of the production casing 40. The centralizers 12 are then operated to extend from the elongated housing 4 of the well completion device 2. The centralizers 12 push against and contact the inner surface of the production casing 40 to stabilize the well completion device 2 within the production casing 40. Once the well completion device 2 has been stabilized within the production casing 40, the electrode(s) 10 are extended from the elongated housing 4 to create apertures or holes within the production casing 40. In traditional EDM, a second electrode (the “work piece”) would be present, and it would be the differential in current between the work piece and the tool that creates the spark that would mine material from the work piece. In the present disclosure, however, the production casing 40 functions as the “work piece” electrode.

The well completion device 2 should preferably be manufactured such that it can conduct sufficient electricity to produce a spark of sufficient energy and heat to mine the production casing 40. Different materials from which the electrode(s) 10 can be manufactured will enable the electrode(s) 10 to conduct different maximum amperages, thereby producing sparks of different maximum intensities and heats. Amperage in the range of 50 to 150 amps will enable the present disclosure to function in an intended manner, but other amperages (higher and lower) may be utilized depending on the material from which the electrode(s) 10 is manufactured and the material of the production casing 40 that must be mined away. In a preferred embodiment, the electrode(s) 10 included with the elongated body 4 may be manufactured from copper, brass, or graphite.

In traditional EDM, the work piece is held still and the tool is continuously moved closer to the work piece until the spark occurs, mining material from the work piece. Once the spark occurs, the tool is temporarily moved away from the work piece and/or the power is temporarily cut from the electrode, and the work piece is then washed with dielectric fluid. Thereafter, the tool is again moved close to the work piece and/or power is restored to the electrode until the electrode again sparks. This process is referred to herein as a “cycle” and, in traditional EDM, a cycle occurs so rapidly that it appears to the naked eye that the spark is continuously mining material from the work piece.

For the present disclosure, the electrode(s) 10 of the well completion device 2, connected to the power supply 48, must be moved close to the production casing 40 until a spark occurs that mines away a portion of the production casing 40. Once the spark occurs, the electrode(s) 10 is temporarily moved away from the production casing 40 and the area of the production casing 40 where the spark mined away material is washed with fresh water or brine water. The fresh water or brine water may be directed through an annulus of the coil tubing string 38 and out from a ported sleeve positioned on top of the well completion device 2. In another example, the fresh water or brine water may be pumped outside of the coil tubing string 38 and past the well completion device 2. Alternatively, the electrode(s) 10 may be kept in place and the power supply 48 may temporarily cease providing electrical current to the electrode(s) while the mined material is washed away with fresh or brine water. In yet another example, the electrode(s) 10 may be moved away from the production casing 40 and the power supply 48 may temporarily cease providing power to the electrode(s) 10 while the mined material is washed away with fresh or brine water. In another example of the present disclosure, instead of extending and retracting the electrode(s), the well completion tool 2 itself may be moved towards and away from the production casing 40 to mine material from the production casing 40. In one example, the well completion tool 2 is moved towards and away from the production casing 40 by using the centralizer 12 to push or pull the well completion device 2 in different directions within the production casing 40.

The apparatus and method of the present disclosure (and set forth more fully below) may use fresh water or brine water as opposed to dielectric fluid as is used in traditional EDM processes. In traditional EDM, dielectric is used because it enables the traditional EDM process to obtain the tight tolerances that allow for very detailed machining of small parts. But in using the well completion device 2 disclosed herein according to the method disclosed herein, tight tolerances are not necessary. Instead, the present well completion device 2 and method are focused on ensuring that the production casing 40 and well wall that is beneath the casing are mined to create fissures that enable access to hydrocarbons adjacent to the drilled well. Once the mined area of the production casing 40 is washed, the electrode(s) 10 may again be moved close to the production casing 40 and/or (as needed) the power supply 48 may again supply power to the electrode(s) until the spark again occurs to mine away a portion of the production casing 40. This constitutes a “cycle” of the present disclosure.

The present disclosure may optionally use multiple electrodes 10 that are machining the production casing 40 simultaneously. This will reduce the amount of time needed to reposition the well completion device 2 in a different position within the production casing 40, which will allow the efficiency and effectiveness of the process to be advantageous over existing methods of perforating, sleeve systems, and other pieces of completion equipment.

The present disclosure may also include additional elements traditionally found in well completion systems. For instance, the elongated body 4 may include an end cap and a capsule guard. By including such elements, the well completion device 2 is able to function more effectively within the environment found in underground wells.

The present disclosure includes a novel method of EDM. In particular, the method of the EDM process disclosed herein is novel in that the inside production casing wall is the work piece and the work piece is washed with fresh water or brine water, as opposed to dielectric fluid. Machining a tubular work piece from the inside out has not yet been performed in the current art. Utilizing the present invention and method, the well completion device 2 may be lowered into a tubular without installing any permanent or semi-permanent housing. The well completion device 2 of the present disclosure is thus an “independent” apparatus that may be utilized in any well without the need to install additional housing or machinery to enable the tool's use. Furthermore, being able to use fresh water or brine water instead of dielectric fluid results in the EDM method disclosed herein being faster and cheaper, which is a significant advantage within the industry. Extracting oil and natural gas from underground reserves is a very expensive process. Enabling users of the present invention and method disclosed herein to save time and money in the process of extracting oil and natural gas from underground reserves will provide users of the present invention and method a competitive advantage in the marketplace. It is also contemplated that this novel method may be used in non-oil and gas applications to create apertures or holes in a casing.

While this disclosure has been described as having exemplary designs, the present disclosure can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims.

Claims

1. An apparatus for performing electrical discharge machining within a well, comprising:

an elongated body comprising a first end and a second end and defining an interior cavity; and

at least one electrode positioned within the elongated body,

wherein the apparatus is configured to be connected to a power supply that enables electrical current to be supplied to the electrode to mine material from a production casing wall inside of a wellbore.

2. The apparatus of claim 1, wherein the electrode is radially adjustable relative to the elongated body.

3. The apparatus of claim 1, wherein the at least one electrode comprises a plurality of electrodes that are circumferentially spaced apart from one another in the elongated body.

4. The apparatus of claim 1, further comprising at least one centralizer provided within the elongated body,

wherein the centralizer is configured to stabilize the elongated body within the production casing.

5. The apparatus of claim 4, wherein the centralizer is radially adjustable relative to the elongated body.

6. The apparatus of claim 4, wherein the at least one centralizer comprises a plurality of centralizers that are circumferentially spaced apart from one another in the elongated body.

7. The apparatus of claim 1, wherein the at least one electrode is positioned between a first centralizer and a second centralizer on the elongated body,

wherein the first and second centralizers are configured to stabilize the elongated body within the production casing.

8. A system for performing electrical discharge machining within a well, comprising:

a well completion device, comprising: an elongated body comprising a first end and a second end and defining an interior cavity; and at least one electrode positioned within the elongated body,

a power supply operatively connected to the well completion device; and

a control system operatively connected to the well completion device to operate the well completion device,

wherein the apparatus is configured to be connected to a power supply that enables electrical current to be supplied to the electrode to mine material from a production casing wall inside of a wellbore.

9. The system of claim 8, further comprising an isolation tool connected to the well completion device,

wherein the isolation tool is configured to isolate the well completion device from debris that may fall into the wellbore.

10. The system of claim 8, further comprising a half-moon swivel connected to the well completion device to stabilize the well completion device within the production casing.

11. The system of claim 8, wherein the electrode is radially adjustable relative to the elongated body.

12. The system of claim 8, further comprising at least one centralizer provided within the elongated body,

wherein the centralizer is configured to stabilize the elongated body within the production casing.

13. The system of claim 12, wherein the centralizer is radially adjustable relative to the elongated body.

14. The system of claim 8, wherein the at least one electrode is positioned between a first centralizer and a second centralizer on the elongated body,

wherein the first and second centralizers are configured to stabilize the elongated body within the production casing.

15. A method of performing electrical discharge machining within a well, comprising:

(a) inserting a well completion device into a production casing positioned within a wellbore, the well completion tool comprising an elongated body comprising a first end and a second end and defining an interior cavity, and at least one electrode positioned within the elongated body;

(b) bringing the at least one electrode adjacent an inner surface of the production casing;

(c) generating an electrical spark between the at least one electrode and the inner surface of the production casing to mine material from the production casing;

(d) ceasing generation of the electrical spark between the at least one electrode and the inner surface of the production casing;

(e) washing the production casing with water to clean the area of the production casing that is being mined; and

(f) repeating steps (c)-(e) until an aperture is created within the production casing.

16. The method of claim 15, wherein the water is fresh water or brine water.

17. The method of claim 15, wherein step (b) comprises extending the at least one electrode from the elongated body or moving the elongated body adjacent the inner surface of the production casing.

18. The method of claim 15, further comprising, before step (b), stabilizing the well completion device within the production casing.

19. The method of claim 18, wherein the well completion device is stabilized in the production casing using at least one centralizer that radially extends from the elongated body.

20. The method of claim 15, further comprising positioning an isolation tool on top of the well completion device to prevent debris from an opening of the wellbore from damaging the well completion device.