Encapsulated Polymer Shell for Subterranean Permeability Control
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Solution Overview
Problem
Existing methods for modifying subterranean formation permeability using polymer solutions are limited by mechanical and chemical degradation, leading to reduced effectiveness and the need for cross-linking agents that are hazardous and difficult to control.
Innovation Solution
A method involving a dispersion of a hydrophilic phase in a lipophilic phase with a linear (co)polymer encapsulated in a shell, which increases viscosity upon release, protecting the polymer from degradation and allowing targeted permeability modification without cross-linking agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer solutions are injected into high-permeability zones to reduce water permeability, then water permeability is reduced and hydrocarbon recovery is improved, but the polymers undergo mechanical and chemical degradation reducing their effectiveness
Solution Approach 1:
The patent applies preliminary action by pre-protecting the polymer with a shell structure before injection. The encapsulated polymer is protected from mechanical degradation during injection and chemical degradation from oxygen and reducing species in the formation, ensuring the polymer remains effective when it reaches the target zone.
Solution Approach 2:
The patent implements beforehand cushioning by using a shell structure that cushions the polymer against mechanical stresses during injection through nozzles and pumps. This protective shell prevents the polymer from undergoing degradation before it reaches the formation zone to be treated.
2Ease of manufacture
If cross-linking agents are added to polymer solutions to control gelation, then gelation kinetics can be delayed, but the methods become unreliable and use hazardous materials like chromium salts
Solution Approach 1:
The patent applies the taking out principle by removing cross-linking agents and hazardous materials from the polymer solution system. Instead of using chemical cross-linkers, the invention relies on the physical encapsulation and controlled release of the polymer, eliminating the need for hazardous substances like chromium salts while maintaining gelation control.
Solution Approach 2:
The patent uses an intermediary approach by introducing a shell structure as a mediator between the polymer and the external environment. This shell controls the release of the polymer and its interaction with the formation, replacing the need for cross-linking agents while providing controlled gelation kinetics without hazardous materials.
3Reliability
If high polymer concentrations are used to overcome degradation, then polymer effectiveness is maintained, but the cost and complexity of the treatment increases
Solution Approach 1:
By pre-protecting the polymer with a shell structure, the patent eliminates the need to use excessive polymer concentrations to compensate for degradation. The preliminary protection ensures that the polymer remains effective at lower concentrations, simplifying the treatment process and reducing complexity.
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 method effectively protects polymers from mechanical and chemical degradation, maintaining injectivity and allowing precise blocking of high-permeability zones, enhancing hydrocarbon recovery by ensuring the polymer's integrity and delayed viscosification.
Implementation Method 1
the (co)polymer being encapsulated in a shell
Implementation Method 2
a dispersion of a hydrophilic phase in a lipophilic phase
Implementation Method 3
the viscosity of the injection fluid is greater than the viscosity of the oil present in the formation
Implementation Method 4
Injecting viscous or gelled polymer solutions into subterranean formations
Implementation Method 5
the shell being capable of being degraded under the temperature and/or pH conditions of the subterranean formation
Data Source
AI summary
The present invention relates to a method for modifying the water permeability of a subterranean formation which comprises oil, said method comprising at least the following steps:Preparing an injection fluid from a dispersion of a hydrophilic phase in a lipophilic phase, with water or brine, the dispersion comprising:a hydrophilic phase comprising at least one linear (co)polymer E,a lipophilic phase,at least one interface polymer composed of at least one monomer of formula (I):Injecting the injection fluid into the subterranean formation, comprising a linear (co)polymer E concentration, such that when released and in contact with water, the viscosity of the injection fluid is greater than the viscosity of the oil in the formation.