CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Application No. 15/662610, filed on July 28, 2017, which claims the benefit of U.S. Application No. 15/406040, filed January 13, 2017, both of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The invention relates generally to methods for actuating a downhole tool using a power charge within a wellbore.

2. Description of the Related Art

[0002] Power charges have been used to generate gases needed to apply

compressive force for an affixed setting tool. A typical use for a power charge is as the motive force for a wireline setting tool. Such a setting tool is used to set bridge plugs, cement retainers and production packers or other downhole devices which must be anchored within a wellbore. Power charges are typically initiated by an igniter which uses electrical current to detonate a small amount of explosive material. A jet of hot burning gases created by the igniter will detonate a secondary pellet which, in turn, initiates the setting tool.

[0003] Some conventional igniters have reliability problems. A nichrome wire which is in contact with black powder within the igniter tends to suffer corrosion. As a result, there can be an unacceptable failure rate for such igniters after one year of shelf life. These conventional igniters are usually rated as explosive material, requiring special packaging and handling and thus increasing costs and delivery times.

SUMMARY OF THE INVENTION

[0004] The invention provides improved systems and methods for activating or setting a tool within a wellbore. Tool actuators are described which include at least one heating igniter which is non-explosive and which initiates a burn of the actuator by generating a high temperature which is sufficient to cause flammable material within the actuator to ignite. Electrical voltage is supplied to the igniter to energize it. In described embodiments, electrical current is provided from the surface via wireline. In one

embodiment, the igniter is a resistive heating element. In an alternative embodiments, the igniter is a coil of wire or a cartridge heater. As the flammable material within the actuator burns, it creates gases which generates an abrupt pressure differential which is useful for actuation of a downhole tool. In some embodiments, the pressure differential will exert a compressive axial force which will actuate the downhole tool. In described embodiments, the pressure differential will shift a piston for tool actuation.

[0005] In accordance with described methods of use, a non-explosive heating igniter and flammable material are incorporated into a tool actuator. The tool actuator and an associated downhole tool to be actuated are then run into a wellbore using a running string. The running string may be in the form of either wireline or tubing. When the tool to be actuated is at a location wherein it is desired to actuate the tool, the actuator is initiated by energizing the heating igniter thereby actuating the tool within the wellbore.

[0006] The actuator can be used to actuate (set) a wide range of types of mechanical packers, bridge plugs, composite firac plugs and the like. In addition to packers and plugs, numerous other downhole tools can be actuated or operated using a power charge. Sliding sleeve devices or other tools which use linear motion for actuation can be actuated using the power charge. Methods are described which are useful for actuating a wide variety of tools which use compressive axial force for actuation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For a thorough understanding of the present invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings, wherein like reference numerals designate like or similar elements throughout the several figures of the drawings and wherein:

[0008] Figure 1 is a side, cross-sectional view of an exemplary wellbore containing a packer device and packer setting tool in accordance with the present invention.

[0009] Figure 2 is a side, cross-sectional view of portions of the setting tool from Figure 1 and related components, including a power charge in accordance with the present invention.

[0010] Figure 3 illustrates an exemplary power charge igniter constructed in accordance with the present invention.

[0011] Figure 4 illustrates an alternative embodiment for a power charge igniter constructed in accordance with the present invention.

[0012] Figure 5 depicts a further alternative power charge igniter constructed in accordance with the present invention. [0013] Figure 6 is a side, quarter cross-sectional view of an exemplary sliding sleeve device to be actuated by a power charge igniter in accordance with the present invention.

[0014] Figure 7 is a side, quarter cross-sectional view of the sliding sleeve device of claim 5 following actuation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Figure 1 depicts an exemplary wellbore 10 which has been drilled through the earth 12 from the surface 14. The wellbore 10 is lined with metallic casing 16. A tool string 18 is shown disposed into the wellbore 10. The tool string 18 includes a wireline running string 20 from which is suspended a packer device 22. The packer device 22 may be a compression-set packer of a type known in the art. In the depicted embodiment, the packer device 22 includes an elastomeric packer element 24 which is expanded radially to set against the casing 16 by axial compression.

[0016] The packer device 22 is affixed to an actuator in the form of a packer setting tool 26. The packer setting tool 26 is operable to set packer device 22 by applying compressive force to portions of the packer setting tool 26. Except where otherwise described herein, the packer setting tool 26 can be constructed and operated in the same manner as the E-4 packer setting device which is available commercially from Baker Hughes Incorporated of Houston, Texas. However, the packer device 22 could be any form of mechanical packer, bridge plug, lock, composite frac plug or similar devices which are set within the wellbore 10 by application of compressive axial force.

[0017] Figure 2 illustrates portions of the packer setting tool 26 in greater detail. The packer setting tool 26 includes an outer housing 28 which defines a recess 30 for retaining an actuator or power charge 32. A piston 34 is retained within the housing 28 and is axially moveable therein. Movement of the piston 34 with respect to the housing 28 will cause setting of the packer device 22.

[0018] The actuator/power charge 32 includes a frangible outer casing 36 which contains an amount of non-explosive, but flammable material 38. The flammable material 38 may be made up using different recipes or mixtures, as is known in the art, to allow burning at various rates to allow optimum setting times for different types of packer devices. The flammable material 38 is a material in the solid phase of matter that can readily undergo combustion in the source of ignition under standard circumstances, i.e., without artificially changing variables such as pressure or density or by adding accelerants. Flammable material is readily combustible. It may cause or contribute to fire through friction. Readily combustible materials can be powdered, granular or pasty chemicals which are dangerous if they can be easily ignited by brief contact with an ignition source. Flammable material 38 is very energetic and produces high temperature gaseous products on combustion which leads to high energy density needed for producing the required propulsive force. Flammable material 38 can consist of several chemical ingredients such as oxidizer, fuel, binder, plasticizer, curing agent, stabilizer and cross-linking agent. The specific chemical composition depends on the desired combustion characteristics for a particular application. The flammable material 38 may contain items such as, but not limited to, perchlorates, nitrates, oxamides, sulfur and carbon compounds. Different chemical ingredients and their proportions result in different physical and chemical properties, combustion characteristics and performance. The outer casing 36 is shaped and sized to reside within the recess 30 in a complementary manner. A heating igniter 40 is also contained within the casing 36 in contact with the flammable material 38. Electrical conduit 42 is interconnected with the heating igniter 40. The electrical conduit 42 will extend upwardly along the wireline 20 to an electrical power source 44 (Fig. 1) at surface 14. The electrical power source 44 may be a generator, battery or other source of electrical energy which is sufficient to provide energizing power to the heating igniter 40.

[0019] Figure 3 illustrates an exemplary heating igniter 40 in greater detail. The depicted heating igniter 40 is a metallic resistive heating element which will heat up when electrical current is applied to it. The resistive heating element is preferably made of stainless steel. However, it might also be fashioned from a bimetallic or non-metallic material or other suitable materials. In the depicted embodiment, the resistive heating element is rod shaped. However, it should be understood that the resistive heating element may have other shapes. When energized, the heating igniter 40 should achieve a temperature that is sufficient to reach the ignition temperature of the flammable material 38. This temperature may be in the range of from about 750°F to about 900°F. It is noted, however, that this range of temperature is exemplary only and not intended to limit the invention in any way. It is further noted that the ignition temperature may vary depending upon the type and form of flammable material used, ambient pressure and other conditions.

[0020] Figure 4 illustrates an alternative embodiment for an igniter 40' in accordance with the present invention. The heating igniter 40' is a coil of wire. Current power supplies in the field will provide about 200 volts of electrical power and 1 to 1.5 amps. That power can be used for up to about 10 seconds. Wire size can be varied to provide different watt densities, output temperatures and the like to adjust for different flammable material 38.

[0021] Figure 5 depicts a further alternative embodiment for an igniter 40" in accordance with the present invention. The igniter 40" is a cartridge heater which includes a thin wire wrapped around a core. A thin coating of epoxy or the like protects the wire from damage and shorting. The cartridge heater igniter 40" preferably includes a thermal fuse which will break electrical continuity after the cartridge heater 40" has been heated to the ignition temperature for a predetermined amount of time. The break in electrical continuity would signal to an operator at surface 14 that the power charge 32 has been initiated and its associated downhole tool has been actuated. It is further noted that resistive elements other than the particular constructions described here can be used to create heat to ignite the flammable material 38.

[0022] In an exemplary method of operation, the packer setting tool 26 and packer device 22 are run into the wellbore 10 on wireline running string 20. When the packer device 22 is at a location wherein it is desired to set the packer device 22 within the wellbore 10, the packer setting tool 26 is actuated by initiating the actuator/power charge 32 within. Initiation of a burn of the actuator 32 is done by energizing the heating igniter 40, 40' or 40". As the flammable material 38 burns, it generates gas which will generate an abrupt pressure differential within the casing 36 and rupture the casing 36. The pressure differential will then exert a compressive axial force upon the piston 34. Because heating igniter 40, 40', 40" is non-explosive, it is believed that use of them will provide improved safety and reduced costs.

[0023] Figures 6 and 7 illustrate an instance wherein a sliding sleeve tool 50 is being actuated using an actuator/power charge 52 which is constructed and operates in accordance with the present invention. In this instance, the running string is a string of tubing 54 rather than a wireline running string, such as wireline running string 20 described previously. The tubing string 54 may be coiled tubing or conventional oilfield tubulars which are interconnected in an end-to-end fashion, as is known in the art. The actuator 52 is secured within a tubular actuator housing 56 which includes a central bore 58 through which fluid may be flowed. The actuator housing 56 is affixed to the sliding sleeve tool 50.

Electrical conduit 42 extends from the actuator 52 to an electrical power source, such as electrical power source 44.

[0024] The sliding sleeve device 50 includes an outer housing 60 which defines a bore 62 along its length. Outer lateral flow ports 64 are disposed through the outer housing 60. A sliding sleeve member 66 is retained within the bore 62 and includes a tubular sleeve body 68 having inner lateral flow ports 70 formed therein. The sliding sleeve member 66 is axially moveable within the bore 62 between a first position, wherein the inner lateral flow ports 70 are not aligned with the outer lateral flow ports 64 (Fig. 5), and a second position, wherein the inner lateral flow ports 70 are aligned with the outer lateral flow ports 64 (Fig. 7). When the sliding sleeve member 66 is in the first position, fluid flow through the outer lateral flow ports 64 is blocked by the sleeve body 68, and when the sliding sleeve member 66 is in the second position, fluid flow through the outer lateral flow ports 64 is permitted. When run into the wellbore 10, and prior to actuation, the sliding sleeve member 66 is in the first position.

[0025] The actuator 52 may be constructed and operate in generally the same manner as the actuator 32 described previously. The piston 34 associated with the actuator 52 is affixed to sliding sleeve member 66 within the sliding sleeve tool 50. The sliding sleeve tool 50 is actuated by heating the heating igniter 40, 40' or 40" within the actuator 52 to ignite its flammable material and generate gases and a resulting abrupt pressure

differential. The pressure differential generates compressive force axially downwardly upon the piston 34. Downward movement of the piston 34 shifts the sliding sleeve member 66 from its first position to its second position, as depicted in Figure 6.

[0026] The invention provides an actuator for a downhole tool which, in certain embodiments, generates compressive force in an axial direction. The downhole tools which can be actuated include any of a number of tools which use a pressure differential as a force for actuation. Exemplary tools which can be actuated include any form of mechanical packer, bridge plug, lock, composite frac plug or similar devices which are set within the wellbore 10 by application of compressive force. In other embodiments, the tools which can be actuated include valves, such as sliding sleeve valves. The valves are actuated between open and closed positions by application of an axial compressive force which is provided by the actuator 52.

[0027] During burning of the flammable material 38, the actuator 26, 52 generates gas which results in creation of a pressure differential. As described previously, the pressure differential is useful to generate a compressive axial force which will move a piston 34. However, the pressure differential might actuate a downhole tool by other methods. For example, the pressure differential might cause release of an actuating member, such as a piston, by moving a retaining member is restraining the actuating member against movement. As a result, the actuating member moves and thus actuates the downhole tool. Alternatively, the gas pressure differential actuates may assist another actuating mechanism, such as use of drilling fluid pressure or hydrostatic pressure, in actuating the downhole tool.

[0028] In addition, the invention provides methods for actuating a tool within a wellbore.

[0029] In accordance with the methods, a tool and an associated tool actuator are disposed into a wellbore. Thereafter, a heating igniter is energized with electrical power to cause ignition of flammable material within the tool actuator. Energy resulting from the ignition of the flammable material will move a piston 34 to provide the application of compressive force used to actuate the associated downhole tool.