Polyol Viscosifying Agent for Heavy Oil Sweep Efficiency

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Solution Overview

Problem

Current enhanced oil recovery (EOR) techniques, particularly chemical floods, face challenges with high costs and environmental concerns due to the use of expensive and toxic polymers, which are inefficient in high-temperature reservoirs and require high concentrations, leading to adsorption losses and reduced sweep efficiency in heavy and extra-heavy oil recovery.

Innovation Solution

The use of glycerol and its derivatives as a viscosifying agent to increase the viscosity of the displacing phase, providing a cost-effective, environmentally friendly, and highly soluble option that does not affect reservoir wettability, allowing for improved mobility and sweep efficiency in oil recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If expensive and toxic polymers are used as viscosifying agents in chemical floods, then sweep efficiency can be improved, but cost increases and environmental harm worsens

Engineering Contradiction:

Improvesweep efficiencyVSAvoidenvironmental harm and cost

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces expensive, toxic polymers with inexpensive, biodegradable natural polysaccharides (guar gum, xanthan gum, carboxymethyl cellulose) as viscosifying agents. These natural polymers are derived from renewable plant sources, are biodegradable, and significantly reduce both cost and environmental impact while maintaining effective viscosity enhancement for improved sweep efficiency

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent modifies the chemical composition parameters by substituting synthetic or semi-synthetic polymers with natural polysaccharides having different molecular structures and viscosity characteristics. This parameter change achieves the same functional effect (viscosification) with superior environmental compatibility and cost-effectiveness

Inventive Principle:

Principle #35Parameter changes

2Productivity

If high concentrations of polymers are used to increase displacing phase viscosity, then mobility ratio improves, but adsorption losses increase

Engineering Contradiction:

Improvemobility ratioVSAvoidadsorption losses

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The use of inexpensive natural polysaccharides allows for more aggressive dosing strategies without significant economic penalty. These natural polymers exhibit lower adsorption tendencies compared to synthetic alternatives, reducing subsurface loss while achieving target mobility ratios

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical nature of the viscosifying agent from synthetic/semi-synthetic polymers to natural polysaccharides, which have different adsorption characteristics. This parameter change reduces unwanted adsorption losses to reservoir rock while maintaining the desired viscosity enhancement for improved mobility control

Inventive Principle:

Principle #35Parameter changes

3Productivity

If conventional polymers are used in high-temperature reservoirs, then sweep efficiency can be enhanced, but polymer degradation occurs

Engineering Contradiction:

Improvesweep efficiencyVSAvoidpolymer stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent selects natural polysaccharides with specific thermal stability characteristics suitable for high-temperature reservoir conditions. These natural polymers (particularly xanthan gum and carboxymethyl cellulose) maintain their viscosity-enhancing properties and molecular integrity at elevated temperatures where conventional polymers would degrade, ensuring sustained sweep efficiency improvement

Inventive Principle:

Principle #35Parameter changes

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

Glycerol and its derivatives significantly increase the viscosity of the displacing phase, enhancing oil recovery by achieving favorable mobility ratios and reducing residual oil saturation, making the process more efficient and economically viable for heavy and extra-heavy oil recovery without adverse effects on the reservoir.

Implementation Method 1

glycerol and its derivatives are used as a more cost effective and environmentally friendly viscosifying agent for improved mobility and sweep efficiency

Methodology Applied

Scientific EffectViscosifying:

Data Source

PatentUS11174714B2Polyol for improving sweep efficiency in oil reservoirs

Publication Date: 2021.11.16 CONOCOPHILLIPS CO

AI summary

The proposed method is an improved chemical flooding of an oil reservoir, especially one containing heavy oil or bitumen, that is cheaper than traditional chemical flooding techniques. This is obtained by viscosifying the displacing phase with a polyol, such as glycerol and/or its derivatives. Glycerol and its derivatives are an excellent additive because they are cheaper than the more commonly used chemicals, work only as a viscosifying agent, do not alter the reservoir properties, and have a wide range of viscosity facilitating the displacement of a wider range of heavy oils. This improved chemical flooding can be used with any other enhanced oil recovery technique, including thermal means, solvent assisted and polymer floodings.