Seawater Sulfate Removal via Two-Part Additive Precipitation

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Solution Overview

Problem

Hydraulic fracturing in hydrocarbon reservoirs often requires significant amounts of water, which can deplete freshwater sources, and sulfate ions in seawater can react with rock formations to form scale, reducing hydrocarbon accessibility and damaging the formation.

Innovation Solution

A two-part additive system, such as aminoguanidine hydrochloride and glyoxal, is used to precipitate sulfate ions from seawater, reducing sulfate concentration and preventing scale formation, allowing treated seawater to be used in hydraulic fracturing without depleting freshwater resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If seawater is used for hydraulic fracturing to avoid depleting freshwater sources, then water availability is improved, but sulfate ions in seawater react with rock formations to form scale and damage the formation

Engineering Contradiction:

Improvewater availabilityVSAvoidscale formation

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful sulfate ions in seawater into beneficial crystalline precipitates through chemical reaction with aminoguanidine hydrochloride and glyoxal. The sulfate ions that would otherwise cause scale formation are transformed into removable solid crystals, turning a harmful component into a manageable byproduct that can be filtered out, allowing seawater to be safely used for hydraulic fracturing

Inventive Principle:

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

Solution Approach 2:

The patent extracts and removes sulfate ions from seawater through precipitation and filtration. The two-part additive system causes sulfate to precipitate as crystalline solids that can be easily separated from the water phase through filtration, effectively removing the harmful component while retaining the water for hydraulic fracturing use

Inventive Principle:

Principle #2Taking out (Extraction)

2Quantity of substance

If traditional desalination techniques are used to remove sulfate from seawater, then sulfate concentration is reduced, but energy expenditure and treatment time are excessive

Engineering Contradiction:

Improvesulfate concentrationVSAvoidenergy expenditure

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical parameters of seawater by introducing aminoguanidine hydrochloride and glyoxal, which alter the solubility characteristics of sulfate. This chemical parameter change causes sulfate to precipitate at room temperature without requiring the high energy input of traditional desalination methods, achieving efficient sulfate removal through chemical transformation rather than thermal or mechanical processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces energy-intensive mechanical desalination systems with a chemical precipitation system. Instead of using high-pressure membranes or thermal distillation, the invention uses chemical reactions to precipitate sulfate, which is then removed by simple filtration, substituting complex mechanical energy-consuming systems with a simpler chemical process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If sulfate precipitates are not removed from seawater, then treatment process is simplified, but scale formation occurs in the rock formation

Engineering Contradiction:

Improvetreatment process complexityVSAvoidformation damage

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent performs preliminary removal of sulfate precipitates through filtration before the treated water is injected into the formation. This advance removal prevents scale formation issues that would occur if precipitates remained in the water, ensuring that only clean treated water contacts the rock formation and proppant, thereby maintaining formation integrity and hydraulic fracturing effectiveness

Inventive Principle:

Principle #10Preliminary action

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 reduces sulfate concentrations in seawater to below 0.02 M, preventing scale formation and maintaining hydraulic fracturing efficiency while conserving freshwater, with the treated seawater being suitable for use in hydrocarbon rock reservoirs.

Implementation Method 1

mixing seawater with a two-part additive system configured to precipitate sulfate from the seawater

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentUS11174178B2Treating seawater for oilfield operations

Publication Date: 2021.11.16 SAUDI ARABIAN OIL CO

AI summary

A method includes mixing seawater with a two-part additive system configured to precipitate sulfate from the seawater; removing the sulfate precipitates from the seawater; and delivering the seawater into an oilfield reservoir.