Foamed Chelating Fluids for Subterranean Scale Removal
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Solution Overview
Problem
Conventional acidizing fluids, particularly those containing hydrochloric acid, pose safety and environmental concerns, and are not suitable for all metallurgical alloys, limiting their use in subterranean well treatments and equipment cleaning due to corrosion and toxicity issues, as well as inefficiencies in scale removal at high temperatures.
Innovation Solution
Foamed chelating agent treatment fluids using aminopolycarboxylic acid chelating agents like glutamic acid diacetic acid (GLDA) that are biodegradable, capable of stabilizing metal cations over a broad pH range, and less corrosive, allowing deeper radial penetration and effective scale removal without precipitation, suitable for use in subterranean formations and equipment cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrochloric acid is used for acidizing treatments, then the acidizing fluid can effectively dissolve formation materials and improve well productivity, but it presents safety concerns, corrosion and toxicity limitations, and is not suitable for all metallurgical alloys
Solution Approach 1:
The patent extracts the harmful hydrochloric acid component from the acidizing system and replaces it with alternative acids (formic acid, acetic acid, or other organic acids) that provide the necessary dissolution capability without the severe corrosion and toxicity problems. This substitution removes the harmful factors while preserving the productivity enhancement function.
Solution Approach 2:
The patent changes the chemical parameters of the acidizing fluid by using different acid types and concentrations, and by controlling pH levels and temperature conditions. These parameter changes allow the fluid to maintain effective dissolution capability while reducing harmful corrosion and toxicity effects on equipment and formations.
2Productivity
If hydrochloric acid is used for scale removal, then it can dissolve certain scales, but it cannot be used on equipment made of certain metallurgical alloys like copper-alloys due to corrosion
Solution Approach 1:
The patent removes hydrochloric acid from the scale removal process and replaces it with alternative chemicals such as EDTA, citric acid, or other chelating agents that can dissolve scale deposits without corroding sensitive metallurgical alloys like copper. This extraction of the harmful substance protects equipment integrity while maintaining flow rate improvement.
Solution Approach 2:
The patent introduces intermediary substances (chelating agents, alternative acids) that act as mediators between the scale deposits and the equipment. These intermediaries selectively dissolve the scale while being compatible with various metallurgical alloys, thus protecting equipment integrity during the cleaning process.
3Productivity
If conventional acidizing fluids are used, then they can remove scale, but they may cause precipitation at high temperatures reducing effectiveness
Solution Approach 1:
The patent changes the chemical composition parameters of the acidizing fluid by using temperature-stable alternative acids and chelating agents that do not precipitate at high temperatures. This parameter change maintains scale removal efficiency across a broader temperature range, preventing the loss of effectiveness that occurs with conventional fluids.
Solution Approach 2:
The patent creates composite treatment fluids that combine alternative acids with chelating agents and other additives in specific formulations. This composite approach ensures temperature stability and prevents precipitation while maintaining effective scale removal capability at elevated temperatures.
4Ease of operation
If foamed acidizing fluids are used, then they provide lightweight properties and improved backflow, but they involve the use of hydrochloric acid which presents safety and environmental concerns
Solution Approach 1:
The patent extracts hydrochloric acid from the foamed acidizing fluid formulation and replaces it with environmentally friendly alternative acids. This removal of the harmful substance eliminates the safety and environmental concerns associated with conventional foamed acidizing fluids while preserving the lightweight properties and improved backflow capability.
Solution Approach 2:
The patent converts the potential harm of acid selection into a benefit by choosing alternative acids that, while potentially less aggressive than hydrochloric acid, provide sufficient dissolution capability without the severe environmental and safety drawbacks. This transformation turns a limitation into an advantage by achieving effective treatment with reduced environmental impact.
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 foamed chelating agent treatment fluids provide deeper radial penetration and effective scale removal at elevated temperatures, are environmentally friendly, and compatible with a variety of metallurgies, enhancing well productivity and equipment efficiency while minimizing environmental impact.
Implementation Method 1
capable of stabilizing metal cations over a broad pH range
Implementation Method 2
foamed acidizing fluid contains compressed gas which improves the ability of the acidizing fluid to backflow out of a subterranean zone
Data Source
AI summary
Treatment fluids and methods include a method that includes the steps of providing or preparing a foamed chelating agent treatment fluid that includes: an aminopolycarboxylic acid chelating agent, an aqueous base fluid, a gas, and a foaming agent, and lacing the foamed chelating agent treatment fluid in a subterranean formation penetrated by a well bore. The aminopolycarboxylic acid chelating agent foamed fluids may also be used in equipment clean-out operations.