GLDA Acidic Solution for Oil Well Stimulation
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Solution Overview
Problem
Existing acidic aqueous solutions for oil well stimulation with chelating agents face challenges in maintaining high chelating agent content and acidic pH during storage and transport, leading to precipitation issues, and lack of solubility in acidic conditions.
Innovation Solution
Acidic aqueous solutions containing glutamic acid N,N-diacetic acid (GLDA) or its salts, with concentrations ranging from 10 wt% to 60 wt%, combined with various acids and additives like surfactants, which maintain solubility even at high acidic pH, preventing iron precipitation and scale formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional chelating agents (NTA, HEDTA) are used in acidic aqueous solutions, then the solutions can prevent iron precipitation, but the chelating agents have limited solubility and cannot maintain high concentrations in highly acidic conditions
Solution Approach 1:
The patent changes the chemical structure parameter of the chelating agent from traditional NTA or HEDTA to GLDA (glutamic acid N,N-diacetic acid). This structural parameter change fundamentally alters the solubility characteristics, enabling the chelating agent to maintain high solubility in highly acidic conditions (pH < 2) while allowing concentrations of 10-60 wt% to remain dissolved during storage and transport.
2Quantity of substance
If the pH is increased to improve chelating agent solubility, then more chelating agent can be dissolved, but the acidifying capability and scale prevention performance decrease
Solution Approach 1:
The patent changes the pH parameter to be highly acidic (pH < 2, preferably pH 0.5-1.5), which is more acidic than conventional treatments. This parameter change, combined with the GLDA structural change, resolves the contradiction by enabling high chelating agent solubility even at these low pH values, thereby maintaining both solubility and scale prevention capability simultaneously.
3Quantity of substance
If high concentrations of chelating agent are added to increase iron binding capacity, then scale prevention improves, but precipitation occurs during storage and transport
Solution Approach 1:
The patent changes both the chemical structure (to GLDA) and the pH parameter (to < 2) to achieve a state where high concentrations of chelating agent (10-60 wt%) remain stably dissolved during storage and transport. This dual parameter change eliminates precipitation issues while maintaining high iron binding capacity and scale prevention performance.
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 solutions exhibit enhanced iron binding capacity and improved scale prevention and removal, suitable for oil field applications, with GLDA showing higher solubility and stability compared to other chelating agents, ensuring effective oil production and well maintenance.
Implementation Method 1
The chelating agent has a dual function; it complexes iron released in the formation and it prevents the (re)precipitation of calcium that dissolves due to the use of the acid.
Implementation Method 2
Currently, oil companies use solutions of NTA in aqueous HCl. The chelating agent has a dual function; it complexes iron released in the formation and it prevents the (re)precipitation of calcium that dissolves due to the use of the acid.
Implementation Method 3
The chelating agent has a dual function; it complexes iron released in the formation and it prevents the (re)precipitation of calcium that dissolves due to the use of the acid.
Data Source
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AI summary
The present invention relates to acidic aqueous solution containing a chelating agent, an acid, and an additive, wherein the chelating agent is glutamic acid N,N-diacetic acid (GLDA) or a salt thereof, wherein the amount of GLDA or the salt thereof is at least 10 wt% and up to 60 wt%, based on the weight of the aqueous solution, wherein the acid is selected from hydrochloric acid, hydrobromic acid, hydrofluoric acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, citric acid, lactic acid, malic acid, tartaric acid, maleic acid, boric acid, hydrogen sulfide, and wherein the additive is selected from the group of surfactants, wetting agents, and emulsifiers