US20220065080A1

US20220065080A1 - Behind casing well perforating and isolation system and related methods

Info

Publication number: US20220065080A1
Application number: US17/009,559
Authority: US
Inventors: Mousa Alkhalidi
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-09-01
Filing date: 2020-09-01
Publication date: 2022-03-03
Also published as: WO2022051293A1; CA3191353A1

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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

REFERENCE TO AN APPENDIX SUBMITTED ON A COMPACT DISC AND INCORPORATED BY REFERENCE OF THE MATERIAL ON THE COMPACT DISC

Not applicable.

STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINT INVENTOR

Reserved for a later date, if necessary.

BACKGROUND OF THE INVENTION

Field of Invention

The disclosed subject matter is in the field of unconventional multistage well completions and perforating systems in conjunction with fracking operations.

Background of the Invention

Petroleum or crude oil and Natural Gas are keystone natural resources. Petroleum may be used to make gasoline which is an important resource of the transportation industry. Petroleum may also be used to make other items such as tires, refrigerators, life jackets, and anesthetics. Natural gas may be used for heating, cooking, electricity generation, or as fuel for vehicles. Beyond its utility as an energy resource, natural gas may also be used as a chemical feedstock for plastics or organic chemicals. In view of the foregoing, anyone can appreciate the need for technologies and related new methods of producing petroleum and natural gas.
One issue with producing crude oil and natural gas is that these products are generally found deep underground in rock formations. The underground location of these resources makes both oil and gas difficult to find and extract. But, because oil and gas are incredibly valuable, an entire industry has been built around the exploration, extraction, and processing of oil and gas.
Oil or natural gas extraction from an underground rock formation requires the drilling of a hole or wellbore into the formation. Many different methods exist by which the oil or natural gas can be brought to the surface via the wellbore. In one method, oil may be recovered with artificial lifting mechanisms such as beam pumps, electrical submersible pumps, or by injecting fluids such as water, steam, or carbon dioxide into a reservoir to increase reservoir pressure and enable the oil or natural gas to flow to surface. Using this method, the amount of oil and gas recovered relative to the amount of oil and gas in the reservoir or recovery rate is determined in part by the geology of the well formation. Particularly important to recovery rates are the permeability and the porosity of the rock formation. For instance, Shale rock formations tends to be more impermeable, inhibiting fluid flows while more permeable Sandstone rock formation allows fluids to flow more freely yielding higher recovery rates.
When attempting to recover oil or gas from a more impermeable rock formation (unconventional formation), it may be necessary to perform extra steps to increase formation permeability and recovery rates by stimulating the well. There are few stimulation methods that are useful such as explosives, acid injection and hydraulic fracking. The most common, safe, and beneficial stimulation method in these troublesome rock formations is hydraulic fracking.
Hydraulic fracturing or fracking is a well stimulation technique that involves injecting fracking fluids consisting of water, chemicals and proppants under high pressure into well formations to crack reservoir rock thus allowing for petroleum, or natural gas to flow substantially uninhibited. After the complete fracking is done, the injected fluids are flowed back from the well back to surface but leaving the hydraulic proppants within formation rock cracks to enable oil and gas continuous flow. Recently, hydraulic fracking has become a widespread stimulation method because of increased recovery rates and new accessibility to unconventional reservoirs such as shale formations, tight sands and coals beds brought about by advances in drilling technology. Hydraulic fracking in conjunction with new drilling techniques like directional drilling, multi-well pads, seismic monitoring, and the like, has changed the economics and the landscape of shale gas production leading to a fracking boom in the United States.
Before fracking, the United States' oil production had been steadily declining for decades and had become highly susceptible to changes in supply from foreign exporters. However, fracking and its related advances in shale production technology and methods has led the United States to become a net oil exporter and energy independent. In the United States, Shale oil production increased eight-fold after fracking was commonplace.
Unconventional reservoirs within Oil and Gas industry are tight formation rocks and in general cannot be produced unless they are fractured, and therefore the completions and processes for producing unconventional wells are unique and different than any other sector. It starts with drilling wells that penetrate the target formation covering 5,000 to 10,000 ft of horizontal reservoir section. Casing is run right after drilling the open hole section followed by cement operation to secure the casing and establish well integrity. Hydraulic fracturing is the chosen stimulation for developing nearly all unconventional reservoirs economically using fracturing fluid, propping material, and pressure to create or restore small fractures in a geological formation and thereby to stimulate hydrocarbon production from oil or gas wells. In this process, hydraulic fracturing fluid is pumped from surface into the wellbore traveling downhole till it reaches some perforated holes at a predetermined depth. The fluid travels through these holes across the casing and surrounding cement into the reservoir to break the rocks and creates conductive flow paths between the target reservoir and the wellbore. The high volume and high-pressured fluids create or restore fractures in the rocks so that hydrocarbon can move from geologic formations to fractures then to wellbores. The unconventional wells are completed in stages, usually ranges from 20 to 60 stages per well across the lateral section. Each stage consists of one isolation plug and multiple clusters (5 to 20 clusters) that are usually distributed across the stage with specific hole (shot) size, number of holes per foot, and with specific orientation across the casing depending on the frac design.
Wireline (or Electric Line) is the most common method for perforating (creating holes) and isolating each stage (via plugs). This is achieved by pumping the perforating guns and plug downhole utilizing water pumps to the desired depth and then setting the plug before initiating the perforating guns via Electric Wireline cable. This provides simple, quick depth control and gun selectivity along with reduced safety risks of personnel and equipment. Pump Down Perforating (PDP) or Plug and Perf (PNP) means Wireline conveyed perforating services where fluid flow is used to transfer a plug and perforation assembly into a horizontal unconventional completion including associated depth control logging services. The detonating objective of a perforating gun is to provide holes within casing and achieve effective flow communication of frac fluid between the cased wellbore and productive reservoir. To achieve this, the perforating gun “penetrates” a pattern of perforations through the casing and cement sheath and into the productive formation. The gun usually contains several shaped explosive charges and available in different ranges of sizes and configurations.
The unconventional fracking operation is carried out by fracking one stage at a time till all stages are completed. The overall steps of multistage fracking operation now days are as follow:

- 1. Wireline tool string consisting of one plug and multiple guns (depending on the number of clusters within the stage) is pumped downhole within casing using water pumps that push the tool string to the desired depth.
- 2. Wireline will set the plug at required depth then move up hole to shoot the first gun (cluster) at a certain depth. After shooting first gun, the Wireline move up hole again to shoot the second gun. This process is repeated till all the guns (clusters) are shot within the stage at the pre-determined depths. The wireline is pulled out of hole at the end of this operation.
- 3. After Wireline is out of hole, the high-pressure pumps will start pumping the frac fluid into the wellbore (casing) till it reaches the holes that were perforated via wireline earlier then flow into formation rocks to create fractures. High volume of frac fluid is pumped at high pressure till the required formation rock area is fully fracked by frac fluid depending on the frac design. The pumps are then shut off and well is handed back to Wireline.
- 4. The Wireline runs in hole right after frac is done to set the plug then shoot the guns (clusters) of the next stage followed by frac with the same process as the previous stage. This operation is repeated till all stages within the well are completed.
- 5. Coiled tubing operations comes after all stages are completed to drill all plugs and put the completed (fracked) well on production. (note: some plugs are dissolvable and do not need drilling with coiled tubing).

Wireline Pump Down Perforating (PDP) always strive to avoid being on any critical path during frac operation, this is due to the high cost associated with Frac fleet. PDP operation can fall within below two operational scenarios:

- 1. Single well operation (stacked frac):
  The Frac operation is conducted on a single well with Wireline being on critical path. i.e. Frac pumps are on standby till the Wireline run is completed. This operation represents 20% of North America completed wells
- 2. Multiple wells operation (zipper frac):
  The Frac operation is conducted on multiple well keeping Wireline away from critical path. On most occasions Wireline get caught up and reduce the efficiency of Frac pumps. Due to efficiency gains with multiple wells operation most companies are drilling pads with 3-5 wells to utilize the frac as much as possible which represents 80% of current frac market place.

LISTING OF RELATED ART

The following is a listing of related art.
U.S. Pat. No. 9,085,969 to Clay, shown above, which discloses, “Bi-directional shaped charges for perforating a wellbore.”
US20110017453A1 to Mytopher discloses a, “Wellbore subassembly with a perforating gun.”
US20050178554A1 to Hromas discloses a, “Technique and Apparatus for Multiple Zone Perforating.”
U.S. Pat. No. 6,009,947 to Wilson discloses a, “Casing conveyed perforator.”
U.S. Pat. No. 4,154,303 to Fournier discloses a, “Valve assembly for controlling liquid flow in a wellbore.”
US20180051532A1 to Smith discloses a, “Frac Plug with Integrated Flapper Valve.”
US20130008671A1 to Booth discloses a, “Wellbore plug and method.”
U.S. Pat. No. 10,502,026 to Saraya discloses, “Methods and systems for fracing.”
U.S. Ser. No. 10/563,476 to Smith discloses a, “Frac plug with integrated flapper valve.”
US20050115708A1 to Jabusch discloses a, “Method and system for transmitting signals through a metal tubular.”
U.S. Pat. No. 6,536,524 to Snider discloses a, “Method and system for performing a casing conveyed perforating process and other operations in wells.”
WO2000065195A1 to Snider discloses a, “Casing conveyed perforating process and apparatus.”
U.S. Pat. No. 5,660,232 to Reinhardt discloses a, “Liner valve with externally mounted perforation charges.”
U.S. Pat. No. 8,127,832 to Bond discloses, “Well stimulation using reaction agents outside the casing.”
U.S. Pat. No. 9,664,013 to Coffey discloses, “Wellbore subassemblies and methods for creating a flowpath.”
U.S. Pat. No. 4,832,134 to Gill discloses a, “Shaped charge assembly with retaining clip.”
U.S. Ser. No. 10/246,974 to Greenway discloses a, “Punch and cut system for tubing.”
CA2953571C to Tolman discloses, “Methods for multi-zone fracture stimulation of a well.”
CN101148982A to Huisheng discloses a, “Side direction detonation symmetrical dual action perforator.”
U.S. Pat. No. 6,684,954 to George discloses a, “Bi-directional explosive transfer subassembly and method for use of same.”
U.S. Pat. No. 5,603,379 to Henke discloses a, “Bi-directional explosive transfer apparatus and method.”

SUMMARY OF THE INVENTION

The main objective of this invention is to eliminate the Wireline Pump Down Perforating (PDP) process and replace it with an innovative electric behind casing perforating and isolation system. It is mainly applicable to the unconventional well completion applications. However, this invention can be also utilized in many different completion applications which involve perforating operations, for example it can replace the Tubing Conveyed Perforating system (TCP) within normal well completions.
The invention approach is to install the perforating guns/charges and the isolation valves control mechanisms on the outside (behind) casing. The isolation valve itself is to be installed inside casing to enable the stage isolation. The casing assembly is then lowered into the open hole drilled section as per normal methods. The cementing operation to be done after casing is in place as per current existing procedures. This novel system will enable direct communication from surface with the perforating guns and isolation valves via one or combination of an electrical cable behind casing, series of acoustic repeaters/receivers behind casing, electromagnetic repeaters/receivers behind casing or fluid pressure pulses within casing.
Below are the three major system components (surface, communication and downhole) of the behind casing perforating and isolation system along with all its sub-components from top of well head all the way to the lateral casing downhole:
Surface System:
This is the surface electronic system which will communicate with all downhole electronic components including addressable switches, perforating guns, detonators, and isolation valve control assemblies. The system has the telemetry software which enable shooting guns/stages selectively by communicating with a specific downhole electric addressable switch to initiate the perforating detonator. As well the system communicates with the isolation valve control assembly to initiate the closure of the downhole isolation valve inside the casing.
Communication System:
The communication system is the means of sending the command from surface to shoot a detonator downhole, activate an isolation valve downhole or get confirmation of downhole event back to surface. It can also be the means of communication between different downhole stage assemblies. The communication is achieved by using one or combination of below four options:
1. Electric Cable: The electric cable enables continuous communication between surface system and downhole components. It is run behind casing utilizing cable clamps to secure around the casing. The cable is typically connected to the ballistic electric interface assembly. An example of this cable can be the one that is currently used with the submersible pump systems.
2. Acoustic Repeaters: An acoustic communication system which enable sending and receiving acoustic signals through casing. This can be achieved via acoustic repeaters or similar telemetry component installed behind casing.
3. Electromagnetic waves: An electromagnetic waves communication system which enable sending and receiving electromagnetic signals through casing and rock formation. This can be achieved via electromagnetic repeaters/receivers or similar telemetry component installed behind casing.
4. Fluid Pressure Pulse: A fluid pressure pulse system that utilizes pressure pulses created at surface by a telemetry pump or variable pressure source. These pulses travel within the fluid system inside casing in which the commands are usually converted into an amplitude- or frequency-modulated pattern of fluid pulses that is received downhole by a specific downhole pressure receiver.
Downhole System:
The downhole system consists of multiple stages which can reach up to 60 stages depending on the well completion design. Each stage assembly consists of several gun assemblies and one ballistic isolation valve assembly connected to each other in series via downhole communication components explained in this document.
Below is full explanation of downhole stage assembly three sub-components:
1. Gun Assembly: Each stage has multiple gun assemblies depending on the stage design. The gun assembly itself consists of the following components:
a. Gun Housing: This is the housing that is attached to casing and surrounding it at the same time. It can be installed in a spiral way outside of casing body and contains all gun assembly components inside to protect it from damage during running casing in hole and cement operation later. The gun housing can be made of metal, composite, or any other material.
b. Addressable Switch: This is an electronic device that has a specific electronic unique address which is read by the surface acquisition system. The addressable switch can be combined with the explosive detonator in one assembly as well. The AS allows shooting all guns within same stage which are connected via ballistic electric line. It eliminates the need to have it installed in each gun assembly within the stage but needs to be installed within the first gun assembly of each full stage to allow shooting the whole stage guns with one addressable switch.
c. Explosive Detonator: This is the detonator that comes after the addressable switch and connects to the explosive detonating cord which goes through the explosive perforating charges. The explosive detonator and addressable switch can be combined in one assembly.
d. Explosive Detonating Cord: This is the cord that contains the explosives inside to transfer the ballistic force from the detonator to explosive charges.
e. Explosive Dual Action Perforating Charges: These charges can be distributed with any specific shot density and phasing. The charges will either face borehole to make a hole in casing or formation to penetrate the reservoir rock. The objective of these charges is to establish connectivity between borehole and formation which enable Frac fluid to reach the formation during frac operation. There two options for configuring these charges; either two separate charges opposite in direction with one separate detonating cord for each charge (total two detonating cords) or one combined charge with two opposite jet directions (one detonating cord).
2. Downhole Communication Components: The main purpose of these components is to accomplish communication between the gun assemblies and ballistic valve isolation assembly within each stage. It consists of the below optional items depending on the desired to communication method:
a. Ballistic Electric Line: The function of this line is to establish electric and ballistic communication within each stage which consists of several gun assemblies and one ballistic isolation valve assembly. It consists of a steel pipe that has a detonating cord inside with an electric line which can be coax (surrounding the detonating cord) or solid (adjacent to detonating cord).
b. Ballistic Electric Interface: This interface instrument objective is to enable the transition from electric cable to the ballistic electric control line or the other way around.
3. Isolation Valve Assembly: This assembly has only the isolation valve itself inside casing while all other control and initiation mechanisms are placed behind casing. It consists of following components:
a. Isolation Valve Housing: This is the housing that is attached to casing and surrounding it at the same time. It is installed outside of the casing body and contains isolation explosive detonator and isolation release assembly components inside to protect it from damage during running casing in hole and cement operation later. The isolation valve housing can be made of metal, composite, or any other material.
b. Addressable Switch: This is an electronic device that has a specific electronic unique address which is read by the surface acquisition system. The addressable switch can be combined with the explosive detonator in one assembly as well. The addressable switch also allows activating the isolation valve inside casing after triggering the detonator which is connected to the isolation release assembly. Every ballistic isolation valve assembly has one addressable switch connected to it to allow triggering that specific isolation valve assembly.
c. Isolation Explosive Detonator: This detonator is connected to downhole communication system as well as the isolation release assembly.
d. Isolation Release Assembly: This is the assembly which activates the isolation valve to shut inside the casing. It has a release rod or another suitable mechanism that prevents the isolation valve from closing unless the isolation explosive detonator was shot.
e. Isolation Valve: This is the isolation valve itself which exist inside the casing and can be only shut in if the isolation release assembly was triggered by the Isolation explosive detonator or similar functional device. This can be a flapper valve, ball valve or any other suitable isolation valve.
Step by Step and Operational Procedure:
The electric behind casing perforating and isolation system can work as per the following generic steps:
1. The supervisor sends a signal from surface to the addressable switch of the deepest isolation valve to trigger shooting the detonator that initiates the isolation release assembly to close the isolation valve inside casing. The confirmation of valve closure can be checked by pumping in fluid right after or via a confirmation signal from a downhole sensor.
2. The supervisor then sends a command to the correct addressable switch to trigger the detonation of the 1^ststage which is the deepest in depth and right above the isolation valve that was closed in previous step. The stage contains multiple gun assemblies depending on well completion design. Gun assemblies within same stage assembly can be all fired at once if utilizing electric cable communication. This is accomplished via the ballistic electric line which contains the detonating cord to transfer the ballistic energy. Another option would be to shoot each gun assembly separately if utilizing the acoustic repeaters, electromagnetic waves, or pressure pulse communication systems. In case the electric cable communication is used then the addressable switch can be mounted inside top gun of the stage (in case the configuration is top bottom shooting) or the deepest gun of the stage (in case the configuration is bottom up shooting).
3. Frac operation is then done across the perforated guns within the specific stage by pumping frac fluid at high pressure and volume as per the completion design.
4. Once Frac operation is completed, supervisor repeats previous three steps for the next stage moving up hole. This operation is repeated till all stages within the well are completed.
5. Coiled tubing or any other suitable intervention comes after all stages are completed to drill or reopen all isolation valves and put the completed (fracked) well on production. (note: some isolation valves are dissolvable and do not need drilling with coiled tubing).
Benefits of the Invention:
The behind casing well perforating and isolation system may be preferable to traditional perforation systems because the behind casing perforating and isolation system eliminates or substantially reduces the need for wireline operation, pumps, and water. The elimination of these components may create environmental, efficiency, and cost benefits. The elimination or reduction of the pumps has major potential environmental benefits. Pump elimination or reduction is estimated to save, on a yearly basis, billions of barrels of water, millions of gallons of diesel fuel, and decrease greenhouse gas emission (CO², NOX, CO, unburned Hydrocarbons) by about 20 million metric tons. There may also be an anticipated 20% yearly cost reduction and an expected 30% gain in pumping hour efficiency due to elimination or reduction of pump down perforating methods, pumps, and water. The behind casing well perforating and isolation system may facilitate a 30% fracking fleet reduction yielding a significant reduction in total asset costs.
The behind casing well perforating and isolation system may also increase efficiency by eliminating standby time, well switching time, time lost during wireline operations, time spent opening and closing well heads, and time spent pressure testing between stages. The behind casing well perforating and isolation system is expected to increase fracking efficiency by roughly 40% to 60%, yielding more than 20 pumping hours daily. Further, the behind casing well perforating and isolation system may enable operators to frack each well completely before moving to the next well within same pad.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

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:

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;

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;

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;

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;

FIG. 5 is a side view of a complete one-gun assembly consisting of five dual action charges (shots) per gun;

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;

FIG. 7 is a cross sectional view of a ballistic release isolation valve assembly showing an example of a flapper isolation valve;

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;

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;

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;

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;

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;

FIG. 12a is a cross sectional view of a ballistic electric control line that can be used with the cable communication system;

FIG. 12b is a right-side view of a partial gun assembly utilizing cable communications and three dual action shots;

FIG. 13 is a schematic of an alternative embodiment of the behind casing well perforating and isolation system utilizing acoustic repeaters;

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,

FIG. 13b is a right-side view of an alternative embodiment of the gun assembly utilizing the acoustic repeaters.

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

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.
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 8 a 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 8 a 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.
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.
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 8 a 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.
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 8 b and detonators 15 c. Further, the mechanical component of the valve assembly 15 may also be controlled by a release mechanism 15 a 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 8 a inside its housing 8 c.
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 8 a gets fired after sending the signal to a specific repeater 4 which activate battery 15 b to trigger detonator 15 c to shoot the dual action charges 8 a via detonating cord 7 c. 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.
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 19 c created at the surface by a telemetry pump 19 a. These pulses travel within the fluid inside the casing 11. The commands are usually converted into an amplitude- or frequency-modulated pattern of pulses 19 c that are received downhole by a downhole pressure receiver/repeater 19 b 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 19 d.
FIG. 5. is showing the critical elements of perforation gun assembly 8, which consists of a plurality of dual action charges 8 a with specific rock formation penetration and casing penetration capabilities, an addressable switch 8 b, a gun housing 8 c, the detonator 15 c and the detonating cord 7 c. The gun housing 8 c is attached to and may surround the casing 11 as shown in FIG. 5. The gun housing 8 c may spiral around the casing 11. The gun housing 8 c may contain and protect all other gun assembly 8 components when casing and cementing the wellbore 14. The gun housing 8 c can be made of metal, composite, or any other material. The addressable switch 8 b is an electronic device that has a unique electronic address which may be read by the surface acquisition system 2. The addressable switch 8 b allows the frac crew to shoot all gun assemblies 8 within same stage 6. The detonator 15 c may be connected to the addressable switch 8 b and the detonating cord 7 c through the charges 8 a. The detonating cord 7 c may contain explosives which transfer ballistic force from the detonator 15 c to the charges 8 c. 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 15 c 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).
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 15 b which may be connected to the detonator 15 c and a group of dual action charges 8 a via detonating cord 7 c. 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 8 a. This process of signaling and charge activation may continue until an entire wellbore 14 has been perforated.
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 15 c connected to a release mechanism 15 a such as a rod, a ballistic electric control line 7, a ballistic electric interface box 5, a valve housing 15 d, an addressable switch 8 b, 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 15 d surrounds and is attached to the casing 11. The valve housing 15 d is installed outside of the casing 11 and contains the detonator 15 c and release mechanism 15 a to protect them from damage during casing running in open hole and cementing operation. The valve housing 15 d can be made of metal, composite, or any other material.
The addressable switch 8 b has a unique electronic address which is read by the surface acquisition system 2. The addressable switch 8 b allows the isolation valve 9 (flapper, ball or similar) to be activated inside casing after triggering the detonator 15 c which is connected to the release mechanism 15 a. Every valve assembly 15 has one addressable switch 8 b to allow specific activation of the valve assembly 15. Activating the detonator 15 c may release the rod 15 a 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.
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 7 a that has a detonating cord 7 c inside with an electric line 7 b which can be coaxial (surrounding the detonating cord 7 c) or solid (adjacent to detonating cord 7 c). The function of the ballistic electric control line 7 is to establish electric and ballistic communication across any combination of addressable switch 8 b, detonator 15 c, and dual charges 8 a within gun assemblies 8 as well as through the valve assemblies 15.
FIG. 9 shows a cross section of a perforated wellbore. As shown in FIG. 9 the dual action charges 8 a 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 8 a 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 8 a capabilities and configurations enable fracking fluid to reach the formation rock 13 during fracking operation. The dual action charges 8 a 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).
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 8 a 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.
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 8 a 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.
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.
A critical element of perforation operations is a gun assembly 8 explained in FIG. 12b which consists of an addressable switch 8 b and detonator 15 c 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 7 a that has a detonating cord 7 c inside with an electric line 7 b which can be coaxial (surrounding the detonating cord 7 c) or solid (adjacent to detonating cord 7 c). The function of the ballistic electric control line 7 is to establish electric and ballistic communication with an addressable switch 8 b, detonator 15 c, and charges 8 a across all gun assemblies 8 and isolation valves assemblies 15.
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 8 a 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 7 c to the battery 15 b which may be connected to the detonator 15 c and a group of charges 8 a. 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 15 b connected to a detonator 15 c connected to a release mechanism 15 a such as a rod, a valve housing 15 d, 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.
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.
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.
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.
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.
All original claims submitted with this specification are incorporated by reference in their entirety as if fully set forth herein.

Claims

I claim:

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.