Abstract
Disclosed is a novel unconventional multi-stage completions system and method called a behind casing perforation and isolation system and methods. It replaces the traditional plug and perforating electric wireline operations, and employs dual action charges and isolation valve control mechanism behind casing with the isolation valves (flapper, ball or similar) inside casing which enable the completion of unconventional multi-stage wells in a more time and cost-efficient way.
Claims
1. The behind casing perforating and isolation system includes one or more stage assemblies consisting of: at least one perforation gun assembly; and, at least one isolation valve assembly.
2. The behind casing perforating and isolation system of claim 1 wherein the perforation gun assembly features a plurality of dual action explosive charges.
3. The behind casing perforation and isolation system of claim 2 wherein the perforation gun assembly is placed outside a wellbore casing.
4. The behind casing perforation and isolation system of claim 3 wherein the isolation valve assembly features isolation valve release mechanism behind casing and isolation valve inside casing.
5. The behind casing perforation and isolation system of claim 4 further comprising a communication system that includes one or combination of following methods: electric cable, acoustic repeater, electromagnetic waves, or fluid pressure pulse systems.
6. The behind casing perforation and isolation system of claim 5 wherein the dual action charge is comprised of two joint explosive charges or two single explosive charges
7. A behind casing perforation system comprising: at least one stage assembly.
8. The behind casing perforation and isolation system of claim 7 wherein the stage assembly is comprised of at least one addressable switch, at least one detonator, a plurality of gun assemblies, and a plurality of isolation valves assemblies (flapper, ball or similar valves) in series.
9. The behind casing perforation and isolation system of claim 8 further comprising a surface acquisition system.
10. The behind casing perforation and isolation system of claim 9 further comprising an electric cable connected to gun assemblies and isolation valve assemblies.
11. The behind casing perforation and isolation system of claim 10 further comprising a ballistic and electric interface box.
12. The behind casing perforation and isolation system of claim 11 further comprising a plurality of acoustic repeaters or electromagnetic waves repeaters
13. The behind casing perforation and isolation system of claim 12 further comprising a ballistic electric control line.
14. The behind casing perforation and isolation system of claim 13 wherein the ballistic electric control line is comprised of a steel pipe, a detonating cord and an electric line.
15. A method of building a well comprising: drilling a vertical then horizontal wellbore into a rock formation; casing the wellbore; filling a wellbore annulus with cement; closing isolation valve and, firing a plurality of dual action perforating guns in a first stage.
16. The method of claim 15 further comprising closing an isolation valve for every stage assembly.
17. The method of claim 16 confirming valve closure with a sensor or building up pressure.
18. The method of claim 17 further comprising firing multiple plurality of dual action charges and perforating guns.
19. The method of claim 18 further comprising pumping a fracking fluid into the wellbore.
20. The method of claim 19 further comprising drilling out or reopening the isolations valves with suitable well intervention technique if needed.
21. The method of claim 20 further comprising flowing back a fracking fluid out of the wellbore before putting well on production.
Description
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0085] Other objectives of the disclosure will become apparent to those skilled in the art once the invention has been shown and described. The manner in which these objectives and other desirable characteristics can be obtained is explained in the following description and attached figures in which:
[0086] FIG. 1 is a schematic of an example of the behind casing well perforating and isolation system and method consisting of multiple stages consisting of four-gun assembly per stage and six shots per gun utilizing electric cable communication and flapper isolation valve;
[0087] FIG. 2 is a schematic of an example of the behind casing well perforating and isolation system and method consisting of one stage with eight-gun assembly per stage and three dual action shots per gun utilizing electric cable communication and flapper isolation valve;
[0088] FIG. 3 is a schematic of an example of the behind casing well perforating and isolation system and method consisting of one stage with six-gun assembly per stage and three dual action shots per gun utilizing acoustic repeaters communication and flapper isolation valve;
[0089] FIG. 4 is a schematic of an example of the behind casing well perforating and isolation system and method consisting of one stage with one-gun assembly per stage and three dual action charges per gun utilizing fluid pressure pulse communication and ball isolation valve;
[0090] FIG. 5 is a side view of a complete one-gun assembly consisting of five dual action charges (shots) per gun;
[0091] FIG. 6 is a perspective view of an alternative embodiment of the gun assembly consisting of three dual action charges and utilizing acoustic repeaters communication method;
[0092] FIG. 7 is a cross sectional view of a ballistic release isolation valve assembly showing an example of a flapper isolation valve;
[0093] FIG. 8 is a cross sectional view of the ballistic electric control line that can be utilized in between gun assemblies employing any of the communication systems;
[0094] FIG. 9 is a cross sectional view of two possible charge configuration and penetration orientation, the left side charge configuration shows two separate charges example and the right side charge configuration shows one combined charge example;
[0095] FIG. 10 is a flow chart that speaks to the steps involved in building a well and fracking a wellbore using the behind casing perforating and isolation system and methods;
[0096] FIG. 11 is a schematic of an example of the behind casing well perforating and isolation system and method consisting of multiple stages with two-gun assembly having 4 shots per gun per stage and utilizing electric cable communication and flapper isolation valve;
[0097] FIG. 12 is a schematic of an example of the behind casing well perforating and isolation system and method consisting of one stage with four-gun assembly per stage and three dual action charges per gun utilizing electric cable communication with clamps and flapper isolation valve;
[0098] FIG. 12a is a cross sectional view of a ballistic electric control line that can be used with the cable communication system;
[0099] FIG. 12b is a right-side view of a partial gun assembly utilizing cable communications and three dual action shots;
[0100] FIG. 13 is a schematic of an alternative embodiment of the behind casing well perforating and isolation system utilizing acoustic repeaters;
[0101] FIG. 13a is a cross sectional view of an acoustic isolation valve assembly showing the behind casing control mechanism as well as the flapper isolation valve inside casing; and,
[0102] FIG. 13b is a right-side view of an alternative embodiment of the gun assembly utilizing the acoustic repeaters.
[0103] It is to be noted, however, that the appended figures illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments that will be appreciated by those reasonably skilled in the relevant arts. Also, figures are not necessarily made to scale but are representative.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0104] Disclosed may be a behind casing well perforating and isolation system and methods. The system and related devices may be generalized as a fracking, perforating and isolation system that places explosive charges and isolation valve control mechanism on the outside of the metal well casing while keeping the isolation valve itself inside casing. It utilizes a form of communication to surface that allows shooting these explosive charges and controlling the isolation valve. The more specific details of this system, devices, and related methods are disclosed in connection with the figures.
[0105] FIG. 1 shows a behind casing perforating and isolation system 1 schematic that speaks to an example of unconventional reservoir completion system which would consist of multiple stages that can range from 20 to 60 stages or more. One stage assembly 6 would consist of at least one or multiple combined gun assemblies 8 and one isolation valve assembly 15. As shown, the behind casing well perforating and isolation system 1 may be generalized as a fracking perforating and isolation system that places a plurality of explosive dual action charges 8a inside gun assembly 8 positioned outside a metal well casing 11 within the cement 12 surrounding it. When detonated, the plurality of dual action charges 8a create perforation tunnels 10 through the casing 11 and cement 12 into formation rock 13 so that fracking fluid can be pumped down a wellbore 14 during fracking operation. The perforated tunnels 10 also enable the oil or gas to flow into the cased wellbore 14 after fracking the whole well stages and removing all isolation valves 9.
[0106] The behind casing well perforating and isolation system 1 is a departure in some ways from traditional fracking systems. Like traditional systems, the behind casing well perforating system 1 penetrates the casing 11, cement liner 12, and a formation rock 13. However, the behind casing well perforating system 1 differs from traditional systems in that the behind casing well perforating system 1 (a) places a plurality of dual action perforation gun assemblies 8 outside the casing 11 instead of inside the casing 11, (b) features isolation valve release mechanisms outside casing 11 combined with isolation valves 9 (flapper valve in this example) inside casing 11 instead of traditional plugs which is run with wireline 9, and, (c) allows for direct continuous communication between the surface system 2 and perforating gun assemblies 8 via an electrical cable 3, series of acoustic repeaters 4, electromagnetic communication or pressure pulse sensor 19, or a combination of all.
[0107] As mentioned, frac operations uses multiple stage assemblies 6 to perforate a wellbore 14. Using multiple stage assemblies 6 allows wellbore 14 to be thoroughly perforated and completed at the lateral reservoir section. As shown an electric cable 3 is connected to a ballistic interface box 5 which uses a ballistic electric control line 7 to connect a plurality of stage assemblies 6. A typical stage operation starts with sending an electric signal to activate the closure of isolation valve 9 which is part of the isolation valve assembly 15. After confirming the isolation valve 9 closure (flapper valve in this example), an electric signal is sent to shoot all charges 8a which are arranged inside multiple gun assemblies 8 within the stage assembly 6 right above the closed isolation valve 9. Once all gun assemblies 8 within the stage assembly 6 are shot then the fracking pumps can start the fracking operation within the same stage. This typical stage operation is repeated till all stages within the wellbore 14 lateral reservoir section are completed.
[0108] FIG. 2 shows a schematic of the behind casing well perforating and isolation system 1. This schematic shows an overall system demonstration of one stage 6. As shown in the schematic, a preferred embodiment of the behind casing well perforating and isolation system 1 features a plurality of components behind and around casing 11. The stage assembly 6 is communicating with a surface acquisition system 2 via an electric cable 3. The stage assembly 6 consists of a plurality of gun assemblies 8 in series followed by the isolation valve assembly 15. The gun assemblies 8 and valve assembly 15 are controlled and activated by addressable switches 8b and detonators 15c. Further, the mechanical component of the valve assembly 15 may also be controlled by a release mechanism 15a such as a rod to activate the isolation valve 9 closure inside casing. The gun assemblies 8 may be attached to the casing 11 via a plurality of gun clamps 16. As shown, the gun assemblies 8 may be oriented anywhere along the outer face of the casing 11, in this example four of gun assembly 8 are placed at top section of casing 11 and another four gun assembly 8 are placed at bottom section of casing 11. As shown in this example, each gun assembly 8 has three or four dual action charges 8a inside its housing 8c.
[0109] FIG. 3 shows a behind casing perforating and isolation system 1 schematic that speaks to a multistage assembly 6 that utilizes the acoustic repeaters 4 communication system. Referring to this schematic, the surface acquisition system 2 takes an inventory of the perforating gun assemblies 8 and isolation valve assembly 15 which include isolation valves 9 (flapper valve in this example) before, during, and after the casing 11 is run and cemented in place. When the wellbore 14 lateral is ready for stage perforation, the behind casing perforating and isolation valve system 1 supervisor would trigger the deepest isolation valve 9 (flapper valve) to close. The isolation valve 9 closure may be confirmed by pumping fluid downhole or preferably by a signal sent back from a downhole sensor. Then the supervisor may send a command to detonate all gun assemblies 8 within the specified stage assembly 6 which is above (shallower than) the closed isolation valve 9 but below (deeper than) a subsequent open isolation valve 9. The stage assembly 6 would contain multiple gun assemblies 8 mounted around casing (top and bottom of casing 11 in this example). The dual action charges 8a gets fired after sending the signal to a specific repeater 4 which activate battery 15b to trigger detonator 15c to shoot the dual action charges 8a via detonating cord 7c. Fracking operation may then be done across the specific stage assembly 6. Once fracking operation is completed, one may repeat the process of closing next shallower isolation valve 9 and firing perforation gun assemblies 8 followed by fracking. This process is repeated until all wellbore lateral stages are completed.
[0110] FIG. 4 speaks to a pressure pulse sensor communication system 19 within the behind casing perforating and isolation system 1. The pressure pulse sensor system 19 utilizes a plurality of pulses 19c created at the surface by a telemetry pump 19a. These pulses travel within the fluid inside the casing 11. The commands are usually converted into an amplitude- or frequency-modulated pattern of pulses 19c that are received downhole by a downhole pressure receiver/repeater 19b to shoot a gun assembly 8 or close an isolation valve 9 (ball valve in this example) which is connected to an acoustic isolation valve assembly 19d.
[0111] FIG. 5. is showing the critical elements of perforation gun assembly 8, which consists of a plurality of dual action charges 8a with specific rock formation penetration and casing penetration capabilities, an addressable switch 8b, a gun housing 8c, the detonator 15c and the detonating cord 7c. The gun housing 8c is attached to and may surround the casing 11 as shown in FIG. 5. The gun housing 8c may spiral around the casing 11. The gun housing 8c may contain and protect all other gun assembly 8 components when casing and cementing the wellbore 14. The gun housing 8c can be made of metal, composite, or any other material. The addressable switch 8b is an electronic device that has a unique electronic address which may be read by the surface acquisition system 2. The addressable switch 8b allows the frac crew to shoot all gun assemblies 8 within same stage 6. The detonator 15c may be connected to the addressable switch 8b and the detonating cord 7c through the charges 8a. The detonating cord 7c may contain explosives which transfer ballistic force from the detonator 15c to the charges 8c. The ballistic electric control line 7 would go through all gun assemblies 8 within same stage assembly 6 to enable shooting all guns within same stage by one detonator 15c which can exist inside most top gun assembly 8 (if top down shooting sequence is used) or inside most bottom gun assembly 8 (if bottom up shooting sequence is used).
[0112] FIG. 6 is a perspective view of an alternative embodiment of the gun assembly 8. This embodiment of the gun assembly 8 features an acoustic repeater 4. The acoustic repeater 4 may be connected via electric cable to the battery 15b which may be connected to the detonator 15c and a group of dual action charges 8a via detonating cord 7c. This embodiment of the gun assembly 8 uses the acoustic repeater 4 to receive a signal through the casing 11 from another acoustic repeater within previous gun assembly 8. The acoustic repeaters 4 transfer the signal to the subsequent gun assemblies' acoustic repeaters 4 till it reaches the correct depth/address gun assembly 8 commanding that specific gun assembly 8 to shoot its dual action charges 8a. This process of signaling and charge activation may continue until an entire wellbore 14 has been perforated.
[0113] Since there are no plugs, the behind casing perforating and isolation system 1 employs an isolation valve assembly 15. As shown by FIG. 7, the valve assembly 15 is for example comprised of a detonator 15c connected to a release mechanism 15a such as a rod, a ballistic electric control line 7, a ballistic electric interface box 5, a valve housing 15d, an addressable switch 8b, and in the preferred embodiment an isolation valve 9 which is flapper in this example, however in other embodiments, the valve may be any isolation valve such as a ball valve. The isolation valve assembly 15 as shown places the flapper valves 9 inside the casing 11 and all other components outside the casing 11. The valve housing 15d surrounds and is attached to the casing 11. The valve housing 15d is installed outside of the casing 11 and contains the detonator 15c and release mechanism 15a to protect them from damage during casing running in open hole and cementing operation. The valve housing 15d can be made of metal, composite, or any other material.
[0114] The addressable switch 8b has a unique electronic address which is read by the surface acquisition system 2. The addressable switch 8b allows the isolation valve 9 (flapper, ball or similar) to be activated inside casing after triggering the detonator 15c which is connected to the release mechanism 15a. Every valve assembly 15 has one addressable switch 8b to allow specific activation of the valve assembly 15. Activating the detonator 15c may release the rod 15a which closes the isolation valve 9 (flapper, ball or similar) inside the casing 11. This isolation valve 9 closure is followed by shooting gun assemblies 8 within that specific stage assembly 6 which enables fracking operation to start right after.
[0115] FIG. 8 shows a cross section of the ballistic electric control line 7. Another downhole communication component of the behind casing perforating and isolation system 1 is the ballistic electric control line 7 which, as shown by FIG. 8 may be comprised of a steel pipe 7a that has a detonating cord 7c inside with an electric line 7b which can be coaxial (surrounding the detonating cord 7c) or solid (adjacent to detonating cord 7c). The function of the ballistic electric control line 7 is to establish electric and ballistic communication across any combination of addressable switch 8b, detonator 15c, and dual charges 8a within gun assemblies 8 as well as through the valve assemblies 15.
[0116] FIG. 9 shows a cross section of a perforated wellbore. As shown in FIG. 9 the dual action charges 8a may be bidirectional, and may act in opposite directions, for instance, towards the wellbore 14 and towards the formation 13 simultaneously. The purpose of the charges 8a which is located inside gun assembly 8 is to establish fluid connectivity between a wellbore 14 and the formation rock 13 across casing 11 and cement 12. The dual charges 8a capabilities and configurations enable fracking fluid to reach the formation rock 13 during fracking operation. The dual action charges 8a can be made of either two separate charges (left side of FIG. 9) or a single bi-directional or combined charge (right side of FIG. 9).
[0117] FIG. 10 is a flow chart that speaks to the steps involved in building a well and fracking a wellbore 14 using the behind casing perforating and isolation system 1. This process may start with drilling a vertical then horizontal wellbore 14 into a rock formation 13, then inserting a casing 11 into the wellbore 14. Once the casing 11 is in place, it is cased by filling the wellbore 14 annulus with cement 12. Thereafter when the well become ready for fracking operation, a signal will be sent to close deepest isolation valve 9. A confirmation of valve closure is made by applying pressure from surface and holding pressure or a signal back to surface. The next step would be shooting a plurality of dual action charges 8a inside perforating gun assemblies 8 within first stage assembly 6. Once the first stage assembly 6 has been perforated a fracking fluid may be pumped into the wellbore 14 at high pressure into the formation rock 13, this concludes a complete stage fracking operation. The subprocess of closing valves 9 then firing gun assemblies 8 after that pumping fracking fluid may be repeated indefinitely until the full lateral wellbore 14 has been adequately fracked. After the fracking pumps are removed from surface, a suitable intervention mechanism is used to drill out or reopen all isolation valves 9. This will enable the well to be put on production as soon as proper completion components are run in hole if needed.
[0118] FIG. 11 is a schematic showing the main components of a behind casing perforating and isolation system 1 utilizing cable communication where each stage assembly 6 consist of two-gun assemblies with four dual charges 8a per gun assembly 8. The surface acquisition system 2 is connected to stage assembly 6 via cable 3 which runs behind casing from surface to electric interface box 5 which serves as an interface to enable the information transmission from the electric cable 3 to a ballistic electric control line 7 which runs across all stage assemblies 6 which includes gun assemblies 8 and isolation valve assemblies 15.
[0119] FIG. 12 shows another schematic of the behind casing perforating and isolation system 1. As shown in the schematic, a preferred embodiment of the behind casing well perforating system 1 features a plurality of components. The behind casing well perforating system 1 features the surface acquisition system 2 which facilitates surface communication with downhole components via an electric cable placed behind the casing 11. The surface acquisition system 2 may enable shooting gun assembles 2 and closing isolation valve 9 (flapper or similar) by activating isolation valve assembly 15. A communication system may be created by complex coordination between an electric cable 3, a plurality of acoustic repeaters 3, and electromagnetic waves or pressure sensor system 19. The electric cable 3 establishes continuous communication with the downhole gun assemblies 8 and ballistic isolation valves assemblies 15. The electric cable 3 may also be placed behind the casing 11 utilizing a plurality of cable clamps 16. The system will enable a surface operator to shoot a gun assembly 8 downhole, activate an isolation valve 9 downhole, or get confirmation of downhole event. Another important component is a ballistic and electric interface box 5 which serves as an interface to enable the information transmission from the electric cable 3 to the ballistic electric control line 7.
[0120] A critical element of perforation operations is a gun assembly 8 explained in FIG. 12b which consists of an addressable switch 8b and detonator 15c installed at the top of the gun assembly 8 followed by other gun assemblies 8 and at least one isolation valve assembly 15 (flapper or similar) in series. Another downhole communication component of the system 1 is the ballistic electric control line 7 which, as shown by FIG. 2a consists of a steel pipe 7a that has a detonating cord 7c inside with an electric line 7b which can be coaxial (surrounding the detonating cord 7c) or solid (adjacent to detonating cord 7c). The function of the ballistic electric control line 7 is to establish electric and ballistic communication with an addressable switch 8b, detonator 15c, and charges 8a across all gun assemblies 8 and isolation valves assemblies 15.
[0121] FIG. 13 speaks to a single stage example of the behind casing perforating and isolation system 1 consisting of total three gun assemblies 6 with three dual charges 8a per gun assembly 8 in combination of one acoustic isolation valve assembly 15 which includes isolation valve 9. The shown embodiment of the behind casing perforating system 1 features a communication system comprised of acoustic repeaters 4. The surface acquisition system communicates with the gun assemblies 8 and isolation valve assembly 15 via acoustic repeaters 4. FIG. 13b speaks to the gun assembly. This embodiment features an acoustic repeater 4. The acoustic repeater 4 may be connected via detonating cord 7c to the battery 15b which may be connected to the detonator 15c and a group of charges 8a. This embodiment of the gun assembly 8 uses the acoustic repeater 4 to receive/send a signal through the casing 11 from/to another acoustic repeater which is installed at a distance before/after its position. FIG. 13a speaks to the details of the acoustic isolation valve assembly 15. The valve assembly 15 is comprised of an acoustic repeater 4 connected to battery 15b connected to a detonator 15c connected to a release mechanism 15a such as a rod, a valve housing 15d, and in the preferred embodiment an isolation valve 9 (flapper, ball or similar). The isolation valve assembly 15 purpose is to isolate the zone below stage assembly 6 by closing the isolation valve 9 before perforation process to commence.
[0122] Although the method and apparatus is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead might be applied, alone or in various combinations, to one or more of the other embodiments of the disclosed method and apparatus, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus, the breadth and scope of the claimed invention should not be limited by any of the above-described embodiments.
[0123] Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open-ended as opposed to limiting. As examples of the foregoing: the term “including” should be read as meaning “including, without limitation” or the like, the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof, the terms “a” or “an” should be read as meaning “at least one,” “one or more,” or the like, and adjectives such as “conventional,” “traditional,” “normal,” “standard,” “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that might be available or known now or at any time in the future. Likewise, where this document refers to technologies that would be apparent or known to one of ordinary skill in the art, such technologies encompass those apparent or known to the skilled artisan now or at any time in the future.
[0124] The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases might be absent. The use of the term “assembly” does not imply that the components or functionality described or claimed as part of the module are all configured in a common package. Indeed, any or all the various components of a module, whether control logic or other components, might be combined in a single package or separately maintained and might further be distributed across multiple locations.
[0125] Additionally, the various embodiments set forth herein are described in terms of exemplary block diagrams, flow charts and other illustrations. As will become apparent to one of ordinary skill in the art after reading this document, the illustrated embodiments and their various alternatives might be implemented without confinement to the illustrated examples. For example, block diagrams and their accompanying description should not be construed as mandating a particular architecture or configuration.
[0126] All original claims submitted with this specification are incorporated by reference in their entirety as if fully set forth herein.
