Chelating Agent Self-Diverting Acidizing Fluids
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Solution Overview
Problem
Acidizing fluids used in subterranean carbonate formations face challenges such as limited radial penetration and excessive fluid loss, which restrict the effectiveness of matrix acidizing treatments due to rapid acid reactivity and the need for additional components like polymeric gels or diverting agents that can cause conductivity blockages.
Innovation Solution
The use of chelating agent-based self-diverting acidizing fluids that form aggregate blocking agents in situ, reducing fluid loss through smaller wormholes and diverting the fluid to primary channels, thereby extending radial penetration without the need for external diverting agents or additional chemical breakers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If polymeric gelling agents are added to control fluid loss, then fluid loss is reduced, but conductivity is blocked and extra removal steps are required
Solution Approach 1:
The acidizing fluid system performs fluid loss control autonomously through in-situ generation of aggregate blocking agents from chelating agents and metal ions, eliminating the need for external polymeric gelling agents and their subsequent removal operations
Solution Approach 2:
The patent removes polymeric gelling agents from the fluid system entirely, replacing their function with a self-generated blocking mechanism that avoids the complexity of gel breaking operations
2Loss of energy
If diverting agents like sand or quartz are used to combat fluid loss, then fluid loss is controlled, but conductivity is blocked and degradation takes weeks or months
Solution Approach 1:
The patent changes the physical-chemical parameters of the fluid system by introducing chelating agents that form aggregate blocking agents through complexation reactions, achieving rapid fluid loss control without long degradation periods associated with particulate diverting agents
3Loss of energy
If viscoelastic surfactants are used to control fluid loss, then fluid loss is reduced, but blockages occur and additional downtime is required
Solution Approach 1:
The system uses self-generated aggregate blocking agents from chelating agent-metal ion complexation to control fluid loss, replacing viscoelastic surfactants that require additional breaking operations and downtime
4Length of stationary object
If prodigious fluid volumes are used to achieve maximum radial penetration, then radial penetration is improved, but costs increase
Solution Approach 1:
The patent converts the harmful effect of rapid acid consumption into a beneficial self-diverting mechanism where aggregate blocking agents form to redirect acid flow to distal regions, achieving enhanced radial penetration without requiring prodigious fluid volumes
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 approach enhances radial penetration and reduces operational costs and complexity by eliminating the need for external diverting agents, allowing for deeper treatment of subterranean formations while ensuring easier flowback and environmental compatibility.
Implementation Method 1
reacting the chelating agent with the metal ions so as to form aggregate blocking agents
Implementation Method 2
allowing the acid to generate metal ions by dissolution of the subterranean formation matrix
Data Source
AI summary
Complexing-acidizing treatment fluids can be used in various subterranean treatment operations. Some methods include: providing or preparing a complexing-acidizing treatment fluid having an acid concentration of about 0.6 Molar, the complexing-acidizing treatment fluid including: an aminopolycarboxylic acid chelating agent, an aqueous base fluid, and an acid, placing the complexing-acidizing treatment fluid in a subterranean formation matrix penetrated by a well bore; allowing the acid to generate metal cations by dissolution of the subterranean formation matrix; reacting the aminopolycarboxylic acid chelating agent with the metal cations so as to form at least a plurality of aggregate blocking agents; and allowing the aggregate blocking agents to divert the complexing-acidizing treatment fluid to a main channel in the subterranean formation matrix that is distinct from a wormhole in the subterranean formation matrix.