CO2 Soluble Polymer Injection for Geological Storage

Solution Overview

Problem

Current methods for injecting supercritical CO2 into deep geological storage sites result in inefficient storage due to uneven 'fingering' of the CO2 injection front, leading to significant loss of storage volume, and there is a need for a cost-effective method to optimize storage and monitor CO2 plume movement.

Innovation Solution

The use of CO2 soluble polymers, such as perfluorocarbons and polyethylene glycol, in a Composition Swing Injection technique to alter the phase behavior of the injected CO2 stream, allowing for separate injection of CO2 and a polymer composition at supercritical or near-supercritical conditions to enhance storage efficiency and serve as a tracer for monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If supercritical CO2 is injected into deep storage sites using conventional methods, then CO2 storage is achieved, but the storage efficiency is low due to uneven sweep and fingering phenomenon resulting in only around 2% of pore volume utilization

Engineering Contradiction:

ImproveCO2 storage efficiencyVSAvoidloss of storage volume

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The patent changes the physical parameters of the injected fluid by adding polymers to CO2, transforming it from a simple supercritical fluid to a polymer-enhanced composition with modified viscosity and density characteristics. This parameter change enables better displacement efficiency and reduces fingering, directly addressing the low storage efficiency problem

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite injection medium by combining CO2 with polymers (such as polyethylene glycol or perfluorocarbon polymers). This composite material exhibits both the density advantages of supercritical CO2 and the viscosity benefits of polymer solutions, enabling improved sweep efficiency and higher pore volume utilization while preventing the loss of storage volume

Inventive Principle:

Principle #40Composite materials

2Reliability

If hydrocarbon components are injected with CO2 to achieve required phase behavior in Composition Swing Injection technique, then phase behavior is optimized, but the cost increases and valuable hydrocarbons are consumed

Engineering Contradiction:

Improvephase behavior controlVSAvoidinjection cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive and valuable hydrocarbon components with cheaper polymer alternatives that can be injected in controlled amounts. These polymers (such as polyethylene glycol) serve the same functional purpose of modifying phase behavior but at significantly lower cost and without consuming valuable hydrocarbon resources

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses polymers to achieve the same phase behavior modification that hydrocarbons provide, but through different chemical mechanisms. The polymers change the rheological properties and solubility characteristics of the CO2 stream, enabling effective composition swing injection without relying on expensive hydrocarbon blends

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

This approach increases the viscosity and density of the CO2 stream, stabilizing the injection front, reducing 'fingering', and allowing for more efficient CO2 storage and monitoring, thereby maximizing storage capacity and reducing costs compared to conventional methods.

Implementation Method 1

The use of CO2 soluble polymers, such as perfluorocarbons and polyethylene glycol, in a Composition Swing Injection technique to alter the phase behavior of the injected CO2 stream, allowing for separate injection of CO2 and a polymer composition at supercritical or near-supercritical conditions to enhance storage efficiency

Methodology Applied

Scientific EffectViscosity enhancement through polymer dissolution: Solvation

Implementation Method 2

The use of CO2 soluble polymers, such as perfluorocarbons and polyethylene glycol, in a Composition Swing Injection technique to alter the phase behavior of the injected CO2 stream, allowing for separate injection of CO2 and a polymer composition at supercritical or near-supercritical conditions

Methodology Applied

Scientific EffectPhase behavior modification through polymer addition: Supercritical Fluid

Implementation Method 3

The CO2 produced during natural gas processing is captured and subsequently injected underground... more than 13 million tons of CO2 had been injected at a rate of approximately 2700 tons per day

Methodology Applied

Scientific EffectCO2 sequestration in geological formations: Absorption (physical)

Data Source

PatentUS9815626B2Method of storing CO<sub>2</sub>

Publication Date: 2017.11.14 EQUINOR ENERGY AS

AI summary

The present invention relates to a method of storing CO2 in a geological formation, said method comprising (i) injecting a first composition comprising CO2 into said formation; and (ii) injecting a second composition comprising CO2 and at least one CO2 soluble polymer into said formation, wherein steps (i) and (ii) are performed separately and in any order and wherein said first and second compositions are different.