Down-hole Electrochemical Ion Separation for Water Chemistry Optimization

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Solution Overview

Problem

Conventional water injection techniques for enhanced oil recovery (EOR) are cost and resource intensive due to the need for specific water chemistry, salinity, and pH, which are difficult to achieve with conventional fluid preparation methods.

Innovation Solution

A system and method utilizing an electrochemical cell and ionic selective membranes to separate and filter fluids by charge, creating anionic and cationic enriched fluids, which are then rotated and injected into the wellbore to achieve a target chemistry for EOR applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional fluid preparation methods are used to achieve specific water chemistry, salinity, and pH, then the required chemistry can be obtained, but the process becomes cost and resource intensive

Engineering Contradiction:

Improvewater chemistry optimizationVSAvoidfluid preparation complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces conventional mechanical/chemical fluid preparation systems with an electrochemical system. An electrochemical cell uses electrical energy to drive ion separation and water splitting reactions, generating acids and bases in situ to adjust pH and ionic composition without requiring complex external chemical injection systems or extensive water treatment infrastructure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system dynamically changes multiple fluid parameters simultaneously (pH, salinity, ionic composition) through controlled electrochemical reactions. By adjusting electrical parameters (current, voltage, duration) and membrane selection, the system can precisely control the chemistry of the injected fluid to match reservoir-specific requirements for optimal oil recovery.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If electrochemical cell with ionic selective membranes is used to separate fluids by charge, then water chemistry can be optimized efficiently, but the device complexity increases

Engineering Contradiction:

Improvewater chemistry optimization efficiencyVSAvoidelectrochemical cell structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent employs ion-selective membranes (such as Nafion® or other cation-exchange membranes) within the electrochemical cell. These porous or gel-like membranes selectively permit passage of specific ions (cations or anions) while blocking others, enabling efficient separation and concentration of ions to achieve target water chemistry. The membranes are integrated directly into the electrochemical cell structure, combining separation and reaction functions in a single compact unit.

Inventive Principle:

Principle #31Porous materials

3Productivity

If specific ionic composition is injected to alter wettability and interfacial tension, then hydrocarbon recovery improves, but the risk of wellbore damage and scaling increases

Engineering Contradiction:

Improvehydrocarbon recoveryVSAvoidwellbore damage and scaling

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system incorporates sensors and control mechanisms to monitor the chemistry of the injected fluid and reservoir conditions in real-time. Based on feedback from pH sensors, conductivity measurements, and reservoir performance data, the electrochemical cell adjusts its operation (current density, membrane selection, flow rates) to maintain optimal ionic composition that improves recovery while staying below thresholds that would cause scaling or wellbore damage.

Inventive Principle:

Principle #23Feedback

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

This approach allows for the efficient and cost-effective optimization of water chemistry in real-time, improving hydrocarbon recovery by altering wettability and interfacial tension, while mitigating wellbore damage and scaling issues.

Implementation Method 1

injecting a fluid into an electrochemical cell and directing an electrical current into the electrochemical cell wherein the fluid separates by charge into a first fluid and a second fluid

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

at least one ionic selective membrane, wherein the ionic selective membrane may be configured to extend diametrically across at least one of the first conduit, the second conduit, the first radial conduit, the first axial conduit, the second radial conduit or the second axial conduit

Methodology Applied

Scientific EffectIon selective membrane filtration: Semipermeable Membrane

Data Source

PatentUS11788392B2Down-hole selective ion removal water ionizer system for subsurface applications

Publication Date: 2023.10.17 SAUDI ARABIAN OIL CO

AI summary

A method for selectively optimizing water chemistry within a wellbore may include positioning a system tubing in the wellbore. The system tubing may include an electrochemical cell, a first chamber, and a second chamber. The method may also include injecting a fluid into the electrochemical cell and directing an electrical current into the electrochemical cell wherein the fluid separates by charge into a first fluid and a second fluid. The method may also include passing the first fluid into the first chamber and the second fluid into the second chamber. Also, the method may include rotating the system tubing, wherein the first fluid flows from the first chamber to the wellbore through a first radial conduit and the second fluid flows from the second chamber to the wellbore through a second radial conduit.