Injection Well Fluids Using Reducing Agents to Prevent Polymer Degradation
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Solution Overview
Problem
Existing methods for oil recovery face challenges such as decreased injection rates due to polymer degradation and gel formation caused by iron in water, leading to reduced oil recovery and potential failure of chemical flooding techniques.
Innovation Solution
Incorporating a reducing agent like sodium metabisulfite into the aqueous injection fluid to prevent polymer degradation and increase injectivity, thereby enhancing oil recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polymer is added to water to increase viscosity for efficient oil displacement, then oil recovery efficiency is improved, but injection rate decreases
Solution Approach 1:
The patent changes the chemical parameters of the injection fluid by adding reducing agents (sodium metabisulfite, sodium sulfite, potassium metabisulfite, or potassium sulfite) to prevent polymer degradation. This allows maintaining higher polymer concentrations and viscosities in the injection fluid, thereby improving oil recovery efficiency while sustaining acceptable injection rates through stabilized polymer performance
2Productivity
If polymer concentration is increased to improve displacement efficiency, then oil recovery is improved, but polymer degradation increases
Solution Approach 1:
The patent converts the harmful effect of oxidizing agents and iron ions that cause polymer degradation into a beneficial outcome by adding reducing agents. The reducing agents react with oxygen and iron ions to prevent oxidation, thereby stabilizing the polymer and extending its service life in the injection fluid, which directly improves polymer reliability and sustained oil recovery performance
Solution Approach 2:
The reducing agents (sodium metabisulfite, sodium sulfite, potassium metabisulfite, or potassium sulfite) act as intermediary substances between the polymer and the harmful oxidizing environment. These intermediaries protect the polymer from degradation by reacting with oxygen and iron ions, thereby maintaining polymer stability and reliability throughout the injection process
3Productivity
If iron is present in water, then gel formation occurs that plugs the formation, but injection rate decreases
Solution Approach 1:
The patent converts the harmful gel-forming action of iron ions into a beneficial stabilization effect by adding reducing agents. The reducing agents prevent iron ions from oxidizing and forming gels, thereby eliminating the harmful gel formation while maintaining high injection rates through sustained fluid flow stability
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 addition of sodium metabisulfite increases the injection rate and prevents polymer degradation, improving the efficiency of oil recovery processes.
Implementation Method 1
The addition of the reducing agent (e.g., sodium metabisulfite) to the water has also been found to prevent degradation of the polymer caused by oxidation of ferrous ions to ferric ions.
Implementation Method 2
The addition of the reducing agent (e.g., sodium metabisulfite) to the water has also been found to prevent degradation of the polymer caused by oxidation of ferrous ions to ferric ions.
Implementation Method 3
Polymer may be added to the water to increase the viscosity of the water for the purpose of more efficiently or completely displacing the oil to production wells.
Data Source
AI summary
Described herein are methods and systems for increasing the injectivity of wells used to inject water or water containing various chemicals such as water-soluble polymers for the purpose of increasing the recovery of hydrocarbons such as crude oil from a hydrocarbon-bearing formation. Injectivity often decreases because of adverse reactions or plugging at or near the wellbore. The treatment procedure involves injecting reducing agents (e.g., sulfite or metabisulfite salts) dissolved in water or water containing other chemicals such as polymers.