Polymer Composition Hydration for Enhanced Oil Recovery

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Solution Overview

Problem

Current polymer compositions for enhanced oil recovery (EOR) face challenges such as lengthy preparation times, issues with hydration, and poor injectivity due to high filter ratios, especially in low permeability reservoirs, requiring complex equipment and processes for handling and mixing polymer emulsions or powders.

Innovation Solution

A polymer composition comprising a powder polymer with an average molecular weight of 0.5 to 30 Million Daltons suspended in a water-soluble solvent with a hydrophilic-lipophilic balance (HLB) of 8 or higher, containing a mixture of non-ionic and anionic surfactants, which is hydratable in less than 4 hours to achieve a polymer concentration of 100 ppm to 50,000 ppm with a filter ratio of less than or equal to 1.5 at 15 psi using a 1.2 µm filter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If polymer powder is suspended in water-soluble solvent with surfactants, then hydration time is reduced to less than 4 hours, but preparation complexity increases due to specific solvent and surfactant requirements

Engineering Contradiction:
Improvehydration timeVSAvoidpreparation complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The polymer is pre-suspended in water-soluble solvent containing surfactants before use, creating a pre-prepared composition that hydrates quickly when contacted with water. This preliminary preparation eliminates the need for complex multi-step mixing processes at the time of use, reducing hydration time to less than 4 hours while maintaining manageable preparation complexity through a single-step suspension process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Water-soluble surfactants act as intermediaries between the hydrophobic polymer powder and hydrophilic water, facilitating rapid hydration. The surfactants reduce interfacial tension and enable the polymer to wet and hydrate quickly without requiring elaborate mixing equipment or prolonged mixing times, thus reducing both time and complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If polymer concentration is increased for effective EOR, then oil recovery efficiency improves, but filter ratio increases causing poor injectivity in low permeability reservoirs

Engineering Contradiction:
Improveoil recovery efficiencyVSAvoidinjectivity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention changes the chemical parameters of the polymer composition by incorporating water-soluble surfactants with specific HLB values (3-18) and using controlled molecular weights (0.5-30 million Daltons). These parameter changes enable the polymer solution to maintain low filter ratios even at high concentrations (100-50,000 ppm), allowing both high oil recovery efficiency and good injectivity in low permeability reservoirs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite system combining polymer, water-soluble solvent, and surfactants in specific ratios (20:80 to 80:20 polymer to solvent). This composite composition synergistically improves both the viscosity-enhancing capability (for oil recovery) and the flow-through capability (low filter ratio), enabling effective EOR while maintaining injectivity in challenging reservoirs.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If polymer emulsion is used instead of powder, then handling and transportation become easier, but carrier oil remains in injected solution reducing EOR efficiency

Engineering Contradiction:
Improvehandling convenienceVSAvoidEOR efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The invention extracts the hydrocarbon carrier oil from traditional polymer emulsions and replaces it with water-soluble solvents and surfactants. This creates a water-based polymer composition that is as easy to handle and transport as emulsions but without the harmful carrier oil residue, thereby maintaining handling convenience while restoring full EOR efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

4Manufacturing precision

If specialized equipment is used for powder handling and mixing, then polymer suspension quality improves, but equipment cost and operational complexity increase

Engineering Contradiction:
Improvesuspension qualityVSAvoidequipment requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The polymer composition is formulated to self-hydrate and self-disperse when contacted with water, utilizing the surfactant system to automatically achieve uniform suspension without requiring high-energy mixers, pre-wettors, or specialized blending equipment. This self-service capability maintains high suspension quality while eliminating complex equipment requirements.

Inventive Principle:
Principle #25Self-service

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 solution enables efficient and convenient preparation and transportation of polymer compositions, improving injectivity and reducing the need for specialized equipment, while maintaining stability and pumpability, thus enhancing oil recovery efficiency.

Implementation Method 1

the polymer composition is hydratable in an aqueous fluid for an injection solution in less than 4 hours

Methodology Applied
Scientific EffectHydration:

Implementation Method 2

the water soluble solvent has an HLB of greater than or equal to 8 and comprises a mixture of non-ionic and anionic surfactants

Methodology Applied
Scientific EffectSurfactant action: Surfactant

Implementation Method 3

having a filter ratio of less than or equal to 1.5 at 15 psi (0.10 MPa) using a 1.2 μm filter

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP3212732B1Polymer compositions
Publication Date: 2022.05.11 CHEVRON USA INC
  • EP3212732B1 patent drawingFigure 1
  • EP3212732B1 patent drawingFigure 2
  • EP3212732B1 patent drawingFigure 3

AI summary

A polymer composition for use in enhancing the production of oil from a formation is disclosed. The composition comprises a powder polymer having an average molecular weight of 0.5 to 30 Million Daltons suspended in a water soluble solvent having an HLB of greater than or equal to 8 and selected from the group of surfactants, glycol ethers, alcohols, co-solvents, and mixtures thereof, at a weight ratio of powder polymer to water soluble solvent ranging from 20:80 to 80:20. The polymer composition is substantially anhydrous and it is hydrated in an aqueous fluid for an injection solution in less than or equal to 4 hours containing a polymer concentration ranging from 100 ppm to 50,000 ppm and having a filter ratio of less than or equal to 1.5 at 15 psi using a 1.2µm filter. Methods for making a polymer suspension and for enhancing oil recovery are also disclosed.