CO2 Injection Well Cement Composition for Mafic Rock Bonding
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Solution Overview
Problem
Conventional cement formulations used in injection wells are not suitable for mafic and ultramafic rocks due to their higher hardness and density, leading to increased energy use, equipment wear, operational costs, and potential corrosion from CO2, and do not provide adequate bonding and durability for CO2 sequestration.
Innovation Solution
A cementitious slurry mixture comprising class G cement, fly ash, microsilica, bio-based additives, and epoxy resin is used to cement the annulus between the well casing and mafic/ultramafic rock, providing enhanced bonding strength, acid resistance, and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional cement formulations are used in injection wells for CO2 sequestration, then the well structure is simple and easy to manufacture, but the cement exhibits inadequate bonding strength and durability due to the higher hardness and density of mafic and ultramafic rocks
Solution Approach 1:
The patent applies composite materials by combining conventional class G cement with epoxy resin and bio-based additives to create a hybrid cement formulation. This composite approach leverages the bonding strength of epoxy and the structural properties of cement, achieving superior adhesion to hard mafic and ultramafic rocks while maintaining formulation feasibility through standardized manufacturing processes.
Solution Approach 2:
The patent changes the chemical and physical parameters of the cement formulation by incorporating epoxy resin (changing from purely hydraulic binding to chemically reactive bonding) and bio-based additives (modifying rheological and curing properties). These parameter changes enable the cement to achieve adequate bonding strength on hard rocks while the formulation remains manufacturable through controlled mixing and curing processes.
2Reliability
If conventional cement is used to seal the annulus, then the manufacturing process is simple, but the cement does not provide adequate acid resistance and durability against CO2 corrosion
Solution Approach 1:
The epoxy-resin-modified cement composite provides enhanced acid resistance through the chemical inertness of cured epoxy and the alkaline buffering capacity of cement. This composite formulation maintains durability against CO2 corrosion while remaining manufacturable using standard cement mixing equipment and procedures, with the added components being easily incorporated into the slurry.
Solution Approach 2:
The bio-based additives act as intermediaries that facilitate compatibility between the epoxy resin and cement matrix, ensuring uniform distribution and proper curing. These additives simplify the manufacturing process by enabling straightforward mixing of otherwise incompatible materials, while the resulting composite provides the required acid resistance and long-term durability in CO2 exposure conditions.
3Productivity
If hydraulic fracturing is performed to create pathways in mafic and ultramafic rock, then fluid flow pathways are created, but energy use and equipment wear increase due to the higher rock density and hardness
Solution Approach 1:
The epoxy-resin-modified cement acts as an intermediary bonding agent that creates strong adhesion between the wellbore and hard mafic/ultramafic rocks. This enhanced bonding eliminates the need for extensive hydraulic fracturing to ensure wellbore stability and zonal isolation, thereby reducing the energy and equipment wear associated with high-pressure fracturing operations in dense, hard rocks.
Solution Approach 2:
The patent changes the bonding interface parameters between cement and rock through epoxy incorporation, achieving bond strengths sufficient to withstand injection pressures without requiring created fracture pathways. This parameter change in interfacial adhesion reduces the need for energy-intensive fracturing operations while maintaining well integrity in hard, dense rock formations.
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 cement mixture exhibits improved bonding strength and durability, with a 5-50% increase in compressive strength and 97% strength retention after exposure to CO2, ensuring well integrity and reducing leakage risks.
Implementation Method 1
The cementitious slurry mixture may be injected into the annulus between the well casing and the injection well wall, an annulus between the well casing and a surface casing having a wider diameter than the well casing, and an annulus between the surface casing and the injection well wall. The cementitious slurry mixture may be cured to form a cured cement.
Implementation Method 2
The cured cement may exhibit a higher bonding strength and a longer durability in terms of strength retention compared to a conventional cement formulation used to cement a CO2 injection well.
Implementation Method 3
CO2-containing fluid may be injected into the CO2 injection well and the CO2-containing fluid is preferably injected into the underground geological formation to thereby react with the underground geological formation formed of mafic and/or ultramafic rock.
Data Source
AI summary
An injection well bored in a mafic and/or ultramafic rock used for carbon dioxide sequestration and a method of cementing a CO2 injection well with a formulated cured. The injection well may include a surface casing and an injection casing placed in a drilled borehole. The injection well may have an open interval permitting fluid communication f into the mafic and/or ultramafic rock. A cured cement may be present between the mafic and/or ultramafic rock and the injection casing and may be formed from a cementitious slurry mixture containing a class G cement, fly ash, microsilica, additives, and an epoxy resin blend. An injection tubing is disposed in the interior of the injection casing, having fluid communication with the interior of the injection casing. A packer connected to the injection tubing may be present as a fluid seal within the injection casing.