Entangled Equilibrium Polymer Networks for Subterranean Fluid Stability
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Solution Overview
Problem
Existing treatment fluids used in subterranean formations at high temperatures and pressures, such as those exceeding 15,000 ft, face challenges with viscosity maintenance and stability, leading to residual damage and increased costs due to polymeric gelling agents and surfactant instability.
Innovation Solution
The use of treatment fluids comprising entangled equilibrium polymer networks, formed by associations of network-forming polymers and worm-like micelles, which enhance viscoelasticity and stability, allowing for controlled viscosity and reduced damage to the formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If polymeric gelling agents are used to maintain viscosity in treatment fluids, then viscosity is improved, but stability and residual damage worsen at high temperatures and pressures
Solution Approach 1:
The patent changes the fundamental parameters of the treatment fluid by using entangled equilibrium polymer networks formed through non-covalent interactions (hydrogen bonding, hydrophobic interactions, ionic interactions) instead of traditional covalent polymeric gelling agents. This allows the fluid to maintain high viscosity while achieving thermal stability above 350°F and pressure stability above 15,000 psi, as the dynamic equilibrium of the network can adapt to extreme conditions without decomposing or leaving residual damage in the formation.
Solution Approach 2:
The treatment fluid employs a composite structure combining water-soluble polymers with amphiphilic block copolymers that form worm-like micelles. This composite system creates an entangled network where polymer chains and micellar structures work synergistically to provide both the required viscosity and enhanced stability at high temperatures and pressures, eliminating the need for high concentrations of single-component gelling agents.
2Force
If surfactant concentrations are increased to improve viscosity, then rheological properties are improved, but formation damage and operational costs worsen
Solution Approach 1:
The patent fundamentally changes the approach to viscosity enhancement by using entangled equilibrium polymer networks that achieve superior rheological properties at much lower concentrations compared to traditional surfactant-based systems. The network structure provides elastic viscosity and shear-thinning behavior without requiring high surfactant concentrations, thereby minimizing formation damage and reducing operational costs associated with surfactant injection and disposal.
3Ease of manufacture
If treatment fluids are designed for shallow wells, then cost and complexity are reduced, but performance at high depths and temperatures worsens
Solution Approach 1:
The patent modifies the chemical composition and molecular architecture of the treatment fluid to achieve performance at extreme depths and temperatures. The entangled equilibrium polymer network, formed by water-soluble polymers and amphiphilic block copolymers, maintains its structural integrity and functional properties at temperatures above 350°F and pressures above 15,000 psi, enabling reliable operation in deep well applications without requiring complex specialized formulations.
4Force
If polymeric gelling agents are used to create gel strength, then suspension capability is improved, but residual damage and cleanup costs worsen
Solution Approach 1:
The patent changes the nature of gel strength generation from permanent covalent crosslinks to dynamic non-covalent interactions in an entangled equilibrium polymer network. This allows the gel structure to provide sufficient suspension capability for proppant and solids during the treatment, while the dynamic equilibrium enables the network to break down and dissipate after treatment, minimizing residual damage and reducing cleanup costs associated with removing polymeric gels from the formation.
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 entangled equilibrium polymer networks provide improved rheological properties, including increased yield point and suspension capabilities, while maintaining stability at high temperatures and reducing the need for high surfactant concentrations, thus minimizing formation damage and operational costs.
Implementation Method 1
The treatment fluids may comprise entangled equilibrium polymer networks, which refer to inter- and intramolecularly associative systems (i.e., networks) of network forming polymer chains and worm-like micelles formed by the interactions of surfactant molecules
Implementation Method 2
worm-like micelles formed by the interactions of surfactant molecules
Implementation Method 3
The entangled equilibrium polymer networks provide improved rheological properties, including increased yield point and suspension capabilities
Data Source
AI summary
Compositions and methods relating to treatment fluids that comprise entangled equilibrium polymer networks in subterranean applications. Such methods include providing a treatment fluid comprising at least one entangled equilibrium polymer network, and placing the treatment fluid in a subterranean formation. Other methods include providing a treatment fluid having a first viscosity comprising an aqueous base fluid and at least one entangled equilibrium polymer network; placing the treatment fluid in a subterranean formation; contacting the treatment fluid with a hydrocarbon; and allowing the viscosity of the treatment fluid to decrease to a second viscosity that is lower than the first viscosity.