Electrochemical Iron Casing Removal in Well Bores
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Solution Overview
Problem
The process of removing iron-containing casing from well bores during plugging and abandonment is costly and time-consuming, requiring significant equipment and multiple steps, which hinders efficient well closure and reclamation for new drilling operations.
Innovation Solution
An electrochemical method involving a cathode and an electrolyte is used to oxidize and dissolve iron in the casing, allowing for selective removal of targeted casing sections while minimizing equipment deployment and operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional mechanical removal methods (milling, rig deployment) are used to remove iron-containing casing, then complete removal of casing can be achieved, but the process becomes costly and time-consuming
Solution Approach 1:
The patent replaces mechanical removal systems (milling rigs, drilling equipment) with an electrochemical system consisting of power sources, electrodes, and electrolyte circulation. This substitution eliminates the need for complex mechanical removal equipment while achieving complete casing dissolution through controlled electrochemical reactions.
Solution Approach 2:
The patent changes the fundamental removal mechanism from mechanical force to electrochemical reactions by controlling parameters such as current density, electrolyte composition, and temperature. This allows for controlled dissolution of iron-containing casing without requiring mechanical removal equipment.
2Reliability
If multiple steps and equipment (rigs, milling equipment) are deployed for well abandonment, then proper plugging and sealing can be achieved, but the process becomes costly and time-consuming
Solution Approach 1:
The patent performs casing removal before the plugging operation, preparing the well bore in advance by dissolving the iron-containing casing electrochemically. This preliminary action eliminates the need for subsequent mechanical removal operations and ensures the well bore is ready for reliable cement plugging without time delays.
Solution Approach 2:
The electrochemical removal process operates continuously, dissolving casing material throughout the well bore section without interruption. This continuous action eliminates the need for multiple discrete mechanical removal operations and equipment deployments, reducing overall process time while maintaining sealing reliability.
3Reliability
If rigs are deployed for casing removal and well abandonment, then complete well closure can be achieved, but the rig cannot be utilized for new well preparation
Solution Approach 1:
The patent replaces the need for specialized abandonment rigs with a portable electrochemical system that can be installed through existing well equipment. This eliminates the requirement for dedicated rig deployment, allowing the same equipment to be used for both abandonment and new well preparation operations.
Solution Approach 2:
The electrochemical system uses the well bore itself as the reaction chamber and employs readily available materials (electrodes, electrolyte) that can be supplied through existing well infrastructure. This self-service approach eliminates the need for external rig support equipment, making the system adaptable to various well conditions without requiring specialized abandonment equipment.
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 efficient, selective removal of iron-containing casing, reducing the need for extensive rig operations and allowing for faster well plugging and abandonment, thereby minimizing costs and optimizing well reclamation.
Implementation Method 1
applying a current so that the iron in said iron-containing casing is oxidised to iron cations
Implementation Method 2
injecting an electrolyte into said well bore, wherein said electrolyte contacts said iron-containing casing and said cathode; applying a current so that the iron in said iron-containing casing is oxidised to iron cations; allowing said iron cations to dissolve in said electrolyte
Data Source
AI summary
There is provided a method for removing iron-containing casing from a well bore comprising providing a cathode in said well bore, wherein said cathode is connected to the negative pole of a power source; connecting said iron-containing casing to the positive pole of said power source; injecting an electrolyte into said well bore, wherein said electrolyte contacts said iron-containing casing and said cathode; applying a current so that the iron in said iron-containing casing is oxidised to iron cations; allowing said iron cations to dissolve in said electrolyte; and removing said electrolyte from said well bore. Also provided are a system for removing iron-containing casing from a well bore, a method for monitoring the removal of an iron-containing casing from a well bore and a method for plugging and abandoning a well.