Anionic Acrylamide Polymers for Sustained Water Permeability Reduction
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Solution Overview
Problem
In subterranean formations, especially carbonate formations, existing relative permeability modifiers fail to provide sustained reduction in water permeability, leading to excessive water production and increased costs due to the need for frequent reapplication, and they often cause viscosity and solubility issues during treatment.
Innovation Solution
Anionic acrylamide polymers with chelating functionality are used, which offer prolonged water permeability reduction by interacting effectively with carbonate surfaces, avoiding the limitations of conventional non-ionic or cationic polymers, and can be synthesized at high concentrations without excessive viscosification, allowing for efficient and cost-effective treatment fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional non-ionic or cationic polymers are used as relative permeability modifiers in carbonate formations, then water permeability reduction is achieved initially, but the effect is not sustained over extended periods requiring frequent reapplication
Solution Approach 1:
The patent changes the chemical parameters of the polymer by introducing anionic charge and chelating functionality to the acrylamide polymer structure. This chemical modification enables sustained interaction with carbonate surfaces through chelation, transforming the temporary effect of conventional polymers into a long-lasting permeability reduction that persists for months without reapplication.
Solution Approach 2:
The invention creates a composite functional structure by combining anionic charge carriers with chelating groups within the polymer chain. This composite design allows the polymer to simultaneously repel water through electrostatic mechanisms and bind strongly to carbonate surfaces through chelation, achieving both immediate water permeability reduction and sustained duration of action.
2Loss of substance
If conventional polymers are used to reduce water permeability, then water production decreases, but hydrocarbon production is also detrimentally impacted
Solution Approach 1:
The patent applies local quality by creating selective permeability modification at different locations within the formation pore structure. The anionic chelating polymer preferentially binds to carbonate mineral surfaces in water-saturated zones, creating localized water barriers while leaving hydrocarbon flow paths relatively unaffected due to the selective interaction mechanisms that favor water-phase disruption over hydrocarbon-phase disruption.
Solution Approach 2:
The invention changes the chemical parameters of the polymer to include anionic charge and chelating functionality, which creates selective interaction with water and carbonate surfaces. This parameter change enables the polymer to differentiate between water and hydrocarbon phases, reducing water permeability through electrostatic repulsion and surface binding while maintaining hydrocarbon flow through non-polar pathways.
3Loss of substance
If treatment fluids are introduced to suppress water flow, then water production is reduced, but the treatment requires judicious placement methods increasing operational complexity
Solution Approach 1:
The patent implements self-service by designing the anionic chelating polymer to automatically and selectively bind to carbonate surfaces upon contact with formation water, without requiring precise placement control or bull heading techniques. The polymer's inherent chemical affinity for carbonate minerals causes it to self-position and self-activate at the appropriate locations within the formation, eliminating the need for complex placement procedures and reducing operational complexity.
4Productivity
If high concentration polymer solutions are prepared for treatment, then treatment efficiency increases, but viscosity becomes excessive affecting pumpability and handling
Solution Approach 1:
The patent changes the charge parameter of the polymer to anionic, which creates electrostatic repulsion between polymer chains and prevents excessive chain entanglement even at high concentrations. This parameter change allows the polymer to maintain lower viscosity at high concentrations compared to neutral or cationic polymers, enabling efficient treatment delivery through standard pumping equipment while preserving treatment effectiveness.
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 anionic acrylamide polymers provide sustained water permeability reduction for extended periods, reducing water production while minimizing impact on hydrocarbon flow, thus enhancing the economic viability of hydrocarbon production and simplifying treatment processes.
Implementation Method 1
Anionic acrylamide polymers with chelating functionality are used, which offer prolonged water permeability reduction by interacting effectively with carbonate surfaces
Data Source
AI summary
Suppressing passage of an aqueous fluid in a subterranean formation in preference to passage of an oleaginous fluid can often be desirable. Methods for suppressing the passage of an aqueous fluid in a subterranean formation, particularly a carbonate formation, can comprise: providing a treatment fluid comprising a carrier fluid and a relative permeability modifier comprising a reaction product of 1) an acrylamide polymer, any copolymer thereof, any derivative thereof, any salt thereof, or any combination thereof, and 2) a plurality of amine-containing compounds or any salt thereof, each amine-containing compound containing a primary amine, a secondary amine, or any combination thereof, and the amine-containing compounds being randomly reacted with at least a portion of the amide groups of the acrylamide polymer; and introducing the treatment fluid into a subterranean formation.