Surfactant Removal from Produced Water via Multivalent Cations

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Solution Overview

Problem

Existing methods struggle to effectively remove surfactant chemicals from produced fluids in enhanced oil recovery processes, particularly in offshore operations, due to their tendency to form emulsions with water, making disposal or reuse challenging.

Innovation Solution

Introducing a treatment fluid containing multivalent cations into the production fluid or produced water to reduce the water solubility of surfactants, allowing for their separation and removal during processing, which can be injected at various stages of the hydrocarbon production and processing system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If surfactant chemicals are used in enhanced oil recovery processes, then the amount of oil recovered is increased, but the surfactants form emulsions with produced water making disposal or reuse challenging

Engineering Contradiction:
Improveamount of oil recoveredVSAvoidemulsion formation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful emulsion formation into a beneficial separation process by using multivalent cations to break the emulsion. The surfactant-emulsified oil is transformed into separable phases through chemical treatment, where multivalent cations neutralize the surfactant's emulsifying effect and enable phase separation, thus converting the harmful emulsion into a manageable separation process

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical parameters of the produced water by introducing multivalent cations (such as calcium, magnesium, or aluminum ions). This parameter change alters the interfacial tension and electrical charge characteristics of the emulsion, causing the surfactant to lose its emulsifying capability and allowing oil-water separation to occur

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If multivalent cations are introduced to break emulsions, then surfactant removal is enabled, but additional chemicals and processing steps are required

Engineering Contradiction:
Improvesurfactant removal capabilityVSAvoidprocessing system complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent employs multivalent cations that are naturally present in many produced water systems or can be easily sourced from common industrial chemicals. The treatment process leverages the natural chemistry of the system, where the multivalent cations automatically neutralize surfactants through electrostatic interactions, reducing the need for complex external treatment systems and minimizing additional processing complexity

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

Facilitates the effective removal of surfactants from produced water, enabling safe disposal or reuse, and improving the efficiency of hydrocarbon production by reducing the challenges associated with surfactant emulsification in separation processes.

Implementation Method 1

multivalent cations in relatively low concentration to break emulsions of oil and water

Methodology Applied
Scientific EffectEmulsion breaking: Flocculation

Implementation Method 2

The multivalent cations act to reduce the water solubility of surfactants in the production fluid

Methodology Applied
Scientific EffectReduction of water solubility: Precipitation

Data Source

PatentEP3280873B1Removal of oil recovery chemicals from production fluids
Publication Date: 2019.06.05 CONOCOPHILLIPS CO
  • EP3280873B1 patent drawingFigure 1
  • EP3280873B1 patent drawingFigure 2
  • EP3280873B1 patent drawingFigure 3

AI summary

Methods and systems for processing production fluid include embodiments for removal of injected chemicals from the production fluid. An embodiment of a method includes receiving production fluid from a borehole in an earth formation, the production fluid including surfactants injected into the earth formation to stimulate production of hydrocarbons therefrom. The method also includes processing the production fluid to separate the production fluid into at least an oil phase and produced water, introducing a treatment fluid from a treatment fluid source into at least one of the production fluid and the produced water, and removing the surfactants from at least the produced water. The treatment fluid includes a concentration of multivalent cations, the multivalent cations configured to reduce water solubility of the surfactants.