Well Abandonment Tool with Pleated Rings and Asphaltic Sealant
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Solution Overview
Problem
Current well abandonment methods fail to provide a reliable and long-lasting seal, leading to hydrocarbon leakage due to elastomeric element deterioration and micro-annulus formation, resulting in environmental hazards and the need for improved sealing solutions.
Innovation Solution
A well abandonment tool utilizing a stack of axially compressible pleated rings and a heated asphaltic sealant to expand and seal the casing, forming a metal-to-metal engagement that resists shrinkage and cracking, combined with a dual locking mechanism to secure the tool in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bridge plug with elastomeric seal ring is used to seal the casing, then the well can be abandoned, but the elastomeric element deteriorates over time causing fluid leakage
Solution Approach 1:
The patent removes the elastomeric seal ring from the system entirely, replacing it with a metal-to-metal sealing mechanism using a bridge plug with a different sealing architecture that eliminates the deteriorating elastomeric component
Solution Approach 2:
The patent employs a composite sealing system combining metal bridge plug body with cement bonding, creating a multi-material solution that replaces the single elastomeric material to achieve long-term reliability without deterioration
2Reliability
If cement is deposited in the casing bore to seal the well, then fluid passage is blocked, but micro-annuli form between cement and casing allowing leakage
Solution Approach 1:
The patent expands the casing preliminarily before cement deposition to close micro-annuli and prevent their formation, ensuring a tight bond between cement and casing from the outset
Solution Approach 2:
The patent applies preliminary expansion force to the casing to counteract the tendency of micro-annuli to form during cement setting, preventing the harmful effect before it occurs
3Reliability
If the casing is cut and capped at surface to abandon the well, then the well is sealed, but existing leaks continue and new micro-annuli may form
Solution Approach 1:
The patent installs the bridge plug and performs casing expansion preliminarily before final abandonment operations, addressing sealing issues at their source rather than attempting to mask them with surface capping
Solution Approach 2:
The patent converts the potential harm of well abandonment (leakage risks) into a benefit by using the abandonment process itself to install a improved sealing system that eliminates the very problems it aims to prevent
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
The tool effectively blocks fluid passage both inside and outside the casing, providing a durable and impermeable seal that maintains the well's integrity over time, reducing the risk of leakage and environmental contamination.
Implementation Method 1
heated asphalt which seals the tool to the casing bore
Implementation Method 2
hot asphaltic sealant to expand and seal the casing, forming a metal-to-metal engagement
Implementation Method 3
The stack of pleated rings is axially compressible on the mandrel. Within the stack, pleated rings flatten, expanding radially to engage the casing
Data Source
AI summary
A tool is provided for use in closing and sealing the cased bore of a well to be abandoned. The tool is run into the bore, the tool having a stack of pleated rings slidably mounted on a tubular mandrel. The tool is engaged with the casing and a charge of hot asphaltic sealant is discharged from a conveyed container to flood the stack and tool annulus. The stack is compressed axially to partly flatten and radially expand the rings to frictionally engage the surrounding casing, the rings and sealant sealing the bore. Further, the rings can expand the heated casing for sealing casing/cement interfaces. The sealant solidifies and creates an impermeable mass sealing against surfaces of the mandrel, stack and casing.