Liner String Shaped Charges with Packers for Uniform Perforation
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Solution Overview
Problem
Current perforating methods using shaped charges in perforating guns result in inconsistent perforation lengths due to variable clearance and gun orientation, leading to suboptimal production and potential for higher penetrations in certain areas over others, necessitating a more controlled and uniform approach for re-fracturing.
Innovation Solution
A liner string with shaped charges positioned at predetermined locations and isolated by packers, allowing for sequential firing of charges in a desired order, such as bottom-up, using ball-actuated sliding sleeves and packers to ensure consistent clearance and optimal formation penetration, with the option to remove the liner for production or injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a perforating gun is deployed by wireline, then the gun can be positioned in the wellbore, but the gun may sit on the casing due to gravity causing variable clearance and inconsistent perforation lengths
Solution Approach 1:
The system divides the wellbore into multiple isolated zones using packers positioned between each shaped charge. This segmentation allows each charge to be fired independently with consistent clearance to the casing, eliminating the gravity-induced variability that affects deployed guns. Each zone can be perforated separately with uniform penetration depth.
Solution Approach 2:
The packers act as intermediaries that mechanically support and centralize the liner string, ensuring constant clearance between the shaped charges and the casing. This intermediary structure eliminates the need for the gun to self-center during deployment, providing consistent perforation lengths without requiring complex positioning mechanisms.
2Productivity
If all shaped charges are fired at once, then the perforating process is completed quickly, but the perforation distribution is not optimized for production
Solution Approach 1:
The liner string is divided into multiple independently fireable sections by packers, allowing sequential activation of shaped charges. This enables optimized perforation distribution by firing charges in a controlled sequence (e.g., bottom-up) rather than all at once, while still maintaining rapid overall operation.
Solution Approach 2:
The system allows preliminary positioning and isolation of multiple charged zones before firing. Packers are pre-positioned to create isolated segments, and charges can be fired in an optimized sequence based on production requirements, combining preparation efficiency with optimized execution.
3Manufacturing precision
If the gun density and phase are precisely controlled, then effective flow paths are achieved, but the process requires complex coordination and is time-consuming
Solution Approach 1:
The liner string with pre-positioned shaped charges and packers is self-contained and self-centralizing. The system automatically maintains constant clearance and proper positioning through its structural design, eliminating the need for complex real-time coordination during operation. This reduces intervention time while maintaining precise charge placement.
Solution Approach 2:
The system changes from a deployed gun configuration (variable clearance) to a centralized liner string configuration (constant clearance). This parameter change in the deployment method simplifies the coordination requirements and reduces operation time while maintaining or improving precision.
4Object-generated harmful factors
If the charge carrier is a heavy well pipe, then most debris is retained after detonation, but the device complexity and weight increase
Solution Approach 1:
The system uses a disposable liner string that is left in the wellbore after perforation. This eliminates the need for a heavy, complex charge carrier that must be retrieved. The liner serves its purpose (providing constant clearance and supporting packers) and then remains as a simple structural element, reducing overall device complexity.
Solution Approach 2:
The heavy well pipe charge carrier is extracted from the system and replaced with a lighter liner string design. The debris retention function is achieved through the liner structure itself rather than a separate heavy carrier, reducing device complexity and weight.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables uniform and optimized perforation distribution, enhancing production or injection efficiency by ensuring consistent perforation lengths and allowing for the removal of the liner and charge remnants, facilitating higher flow rates and reduced intervention costs.
Implementation Method 1
The gun, composed from the shaped charges, the charge carrier, the detonator, and the detonation cord
Implementation Method 2
The high impact pressure (around 10 to 15 million psi) and the tip jet speed (around 25,000 to 30,000 ft./sec). This high pressure overcomes the steel casing and formation strength and forces the solid material radially away from the jet
Implementation Method 3
the detonator, and the detonation cord, is run into the hole and all charges are fired at once
Implementation Method 4
Knowing the precise location of the desired perforations, the liner could be designed with systems of ball-actuated sliding sleeves and shaped charges. The balls would have different sizes, as they are already used. Once a ball opens a sleeve, the corresponding shaped charge can be detonated either mechanically or electrically. Because of the packers, the charge clearance would be constant along the completion guaranteeing perforations of the same length
Implementation Method 5
The fracturing of the newly created perforations enables additional production from surrounding formations, or injection for enhanced recovery through other adjacent wells
Implementation Method 6
Controlled electrolytic materials (CEM) can be used for the ball seat and the balls to facilitate disintegration
Data Source
AI summary
A re-fracturing method involves placement and centralization of a liner string that has shaped charges at predetermined locations that are externally isolated with packers. The shaped charges can be set off in a desired order and re-fracturing can then take place in new locations. In a bottom up order for perforating sequentially larger balls can be landed on seats and developed pressure or component movement generated by applying pressure can be used to set a shaped charge and isolate portions of the borehole below. The balls and even the seats can be later milled out or just allowed to disintegrate or dissolve with well fluids that are present or later added to clear the liner for subsequent production. Alternatively, the liner could be removed by release of the packers before production or injection begins.