Disappearing Expandable Cladding for Well Perforation Sealing
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Solution Overview
Problem
Existing methods for sealing off old perforations in wells are uncertain regarding material delivery completeness and pressure effects on production, with temporary seals potentially impeding subsequent operations due to incomplete disintegration of plugging materials.
Innovation Solution
An expandable tubular made of disintegrating material, such as controlled electrolytic material (CEM), is used to cover existing perforations, allowing new perforations to be made and treated, which then degrades to restore the original well diameter and perforations for resumed production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plugging material is pumped into existing perforations to seal them, then the perforations are sealed off, but the pressure needed to deliver the material adversely affects subsequent production
Solution Approach 1:
The patent uses controlled electrolytic material that changes its physical state through electrochemical reactions. The material is delivered in a soluble form, then transforms into an insoluble plugging material through electrolysis when exposed to formation fluids, allowing sealing without high delivery pressures that would harm production
Solution Approach 2:
The patent replaces mechanical high-pressure delivery systems with an electrochemical process. Instead of pumping material under high pressure into perforations, the system uses electrolysis to transform soluble material into insoluble plugging material in situ, eliminating the need for high-pressure delivery and its adverse effects on production
2Reliability
If plugging material is delivered into perforations to seal them, then sealing is achieved, but it is uncertain whether all plugging material has been effectively disintegrated
Solution Approach 1:
The controlled electrolytic material performs self-disintegration through electrochemical reactions. The material is designed to remain soluble during delivery and then automatically transforms into insoluble plugging material through electrolysis, and subsequently disintegrates可控地 when conditions change, providing self-regulating behavior without requiring external monitoring of disintegration completeness
3Reliability
If a permanent seal is created in perforations, then sealing is reliable, but the original well drift diameter cannot be resumed
Solution Approach 1:
The patent employs a dynamic plugging material that can change its state from soluble to insoluble and back. The controlled electrolytic material provides a temporary seal that is reliable during the intervention operation, but can be controlled to disintegrate afterward, allowing the well drift diameter to be restored for subsequent production operations
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 solution ensures complete and controlled sealing of old perforations, facilitating new perforation and treatment operations without long-term impedance to production, as the expandable tubular disintegrates over time, restoring the original well dimensions.
Implementation Method 1
The clad is made of a disintegrating material such as a controlled electrolytic material known as CEM and is expanded into position to cover the existing perforations. Over time or with exposure to well fluids or temperatures the clad disintegrates and the original well drift diameter is regained
Data Source
AI summary
Perforations in an existing borehole are covered with an expandable clad or elongated tubular that is expanded on location with the expansion equipment then removed. The clad is made of a disintegrating material such as a controlled electrolytic material known as CEM and is expanded into position to cover the existing perforations. One or more plugs are run in with perforating guns and the plugs set with the guns moved away from the set plug and fired to make new perforation. After each new perforation is made a ball is delivered to the plug to isolate a portion of the well and the new perforations are treated such as in a fracturing or another operation. Over time or with exposure to well fluids or temperatures the clad disintegrates and the original well drift diameter is regained so that subsequent production or injection is not impeded.