Liquid Polymer Inversion for Porous-Formation Hydrocarbon Recovery
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Solution Overview
Problem
Existing water-in-oil emulsions of polymers used in enhanced oil recovery (EOR) processes are difficult to invert and often fail to pass through porous structures, limiting their utility, and cannot be efficiently inverted using aqueous media with dissolved salts.
Innovation Solution
Methods for preparing inverted polymer solutions by inverting liquid polymer compositions comprising synthetic (co)polymers dispersed in hydrophobic liquids, using emulsifier and inverting surfactants, and diluting in an aqueous fluid to achieve concentrations of 50 to 15,000 ppm with a filter ratio of 1.5 or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water-in-oil emulsions of polymers are used for enhanced oil recovery, then polymer concentration can be maintained, but the emulsions are difficult to invert and cannot pass through porous structures
Solution Approach 1:
The patent changes the chemical composition parameters of the emulsion by incorporating specific surfactants (anionic, cationic, nonionic, or amphoteric) and adjusting the polymer concentration and molecular weight. These parameter changes enable the emulsion to invert readily when contacted with aqueous media containing dissolved salts, while maintaining adequate polymer concentration for EOR effectiveness.
Solution Approach 2:
The patent creates a composite emulsion system combining polymer, hydrophobic liquid, and multiple types of surfactants (anionic, cationic, nonionic, or amphoteric). This composite material structure allows the emulsion to maintain stability in its water-in-oil form while being capable of inversion to oil-in-water form when needed, resolving the contradiction between maintaining concentration and enabling inversion.
2Quantity of substance
If water-in-oil emulsions of polymers are used for enhanced oil recovery, then polymer concentration can be maintained, but the emulsions fail to pass through porous structures
Solution Approach 1:
The patent adjusts critical parameters including polymer concentration (0.1-10% by weight), polymer molecular weight (10^6-10^9), and surfactant composition (anionic, cationic, nonionic, or amphoteric). These parameter changes ensure the emulsion has appropriate rheological properties to pass through porous reservoir structures while maintaining sufficient polymer concentration for mobility control and EOR effectiveness.
Solution Approach 2:
The surfactant acts as an intermediary substance that mediates between the polymer-hydrophobic liquid mixture and the aqueous reservoir environment. The surfactant enables the emulsion to invert and pass through porous structures by reducing interfacial tension and facilitating the transition from water-in-oil to oil-in-water emulsion structure in the presence of dissolved salts.
3Ease of operation
If existing water-in-oil emulsions are inverted using aqueous medium with dissolved salts, then inversion should occur, but existing emulsions cannot be efficiently inverted
Solution Approach 1:
The patent incorporates specific surfactants (anionic, cationic, nonionic, or amphoteric) as intermediaries that facilitate the inversion process. These surfactants enable efficient inversion of the water-in-oil emulsion to oil-in-water emulsion when contacted with aqueous media containing dissolved salts, ensuring reliable inversion under EOR field conditions.
Solution Approach 2:
The patent optimizes surfactant concentration and type (anionic, cationic, nonionic, or amphoteric) as key parameters to enable efficient inversion. The surfactant composition and concentration are specifically adjusted to ensure the emulsion inverts readily and completely when contacted with aqueous media containing dissolved salts, achieving both ease of operation and reliability.
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 inverted polymer solutions exhibit improved injectivity and flow through hydrocarbon-bearing formations without plugging, enhancing hydrocarbon recovery by increasing flow to production wells.
Implementation Method 1
using emulsifier and inverting surfactants
Implementation Method 2
flow through hydrocarbon-bearing formations without plugging
Data Source
AI summary
Provided herein are liquid polymer (LP) compositions comprising a synthetic (co)polymer (e.g., an acrylamide (co)polymer), as well as methods for preparing inverted polymer solutions by inverting these LP compositions in an aqueous fluid. The resulting inverted polymer solutions can have a concentration of a synthetic (co)polymer (e.g., an acrylamide (co)polymer) of from 50 to 15,000 ppm, and a filter ratio of 1.5 or less at 15 psi using a 1.2 μm filter. Also provided are methods of using these inverted polymer solutions in oil and gas operations, including enhanced oil recovery.