Reactive Rock Reservoir Acidizing with CO2 Microbubbles
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Solution Overview
Problem
Conventional acidizing treatments using strong acids to enhance permeability in reactive geological formations can lead to the formation of insoluble, nonreactive phases that occlude permeability and cause corrosion, while methods lacking strong acids often result in insufficient secondary permeability, affecting the economic viability of geothermal energy, hydrogen, hydrocarbon, and waste disposal operations.
Innovation Solution
A method involving hydraulic fracturing and acidizing with an acidic fracturing fluid containing dissolved CO2 and CO2 micro/nanobubbles, which reacts with reactive rock to form carbonates, enhancing permeability and sequestering CO2, without producing harmful insoluble phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional strong acids are used for acidizing treatments to enhance permeability, then permeability improvement is achieved, but insoluble nonreactive phases are produced that occlude permeability and corrosion occurs
Solution Approach 1:
The patent changes the chemical parameters of the acidizing fluid by using weak acids (acetic acid, formic acid, lactic acid) instead of strong acids, and by adjusting the concentration and composition of the acid mixture. This parameter change allows the acid to react with carbonate minerals to form soluble products while avoiding the formation of insoluble nonreactive phases that occur with strong acids, thus maintaining permeability improvement without the harmful side effects
Solution Approach 2:
The patent introduces an intermediary substance - a weak acid-based chemical agent - that mediates the reaction between the acidizing fluid and carbonate minerals. This intermediary weak acid reacts with carbonate to form soluble acetate, formate, or lactate compounds, which prevents the direct formation of harmful insoluble phases while still achieving the desired permeability enhancement through controlled chemical dissolution
2Productivity
If strong acids are used for acidizing treatments to enhance permeability, then permeability improvement is achieved, but corrosion of wellbore and equipment increases
Solution Approach 1:
The patent changes the chemical strength parameter of the acid by substituting strong acids with weak acids having lower dissociation constants. This parameter change reduces the aggressive corrosive action on wellbore materials and equipment while maintaining sufficient reactivity to dissolve carbonate minerals and enhance permeability, thus achieving a balance between productivity improvement and corrosion mitigation
Solution Approach 2:
The patent employs biodegradable weak acids (acetic, formic, lactic) that are less corrosive and can be broken down metabolically by microorganisms in the formation. These acids serve as a temporary, self-limiting chemical agent that performs its function of carbonate dissolution and permeability enhancement without causing long-term corrosive damage to the wellbore infrastructure, unlike persistent strong acids
3Object-generated harmful factors
If methods lacking strong acids are used to avoid harmful phases, then corrosion is reduced, but secondary permeability is insufficient
Solution Approach 1:
The patent merges multiple mechanisms to achieve permeability enhancement: it combines the chemical dissolution action of weak acids on carbonate minerals with physical stimulation methods such as hydraulic fracturing or steam injection. This combination allows the weak acid to react with carbonate to form soluble products that enhance fracture aperture and create new flow paths, while the physical stimulation method provides the mechanical force needed to create and propagate fractures, together achieving sufficient secondary permeability without the corrosion problems of strong acids
Solution Approach 2:
The patent uses a composite acidizing system that combines weak acids with other chemical additives and physical stimulation methods. This composite approach includes weak acids (acetic, formic, lactic) combined with potential alkaline earth metal ions or other chemical agents that work synergistically to enhance carbonate dissolution and permeability while maintaining low corrosion rates, creating a multi-component system that achieves both goals simultaneously
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 permeability and injectivity in reactive geological formations, facilitating efficient geothermal energy extraction, hydrogen production, hydrocarbon recovery, and waste disposal while minimizing corrosion and maintaining formation integrity.
Implementation Method 1
Igneous (and metamorphic) rocks rich in calcium, magnesium, and iron minerals react with acidic solutions, leading to the formation of secondary minerals such as silicates and carbonates
Implementation Method 2
In-situ mineral carbonation of CO2, for example, uses these reactions to trap injected CO2 permanently in solid carbonate form
Implementation Method 3
well stimulation methods like hydraulic fracturing, thermal fracturing, and acidification
Implementation Method 4
acidification of reactive geological formations... by treating the reactive geological formation with an acidic fluid that includes dissolved CO2
Implementation Method 5
Conventional acidizing treatments generally include strong acids to increase a permeability of a geological formation by dissolving acid soluble minerals
Implementation Method 6
acidic fracturing fluid that includes dissolved CO2 or other weak acids, is enriched with CO2 micro/nanobubbles
Data Source
AI summary
A method of stimulating a geological formation may include positioning an acidic fracturing fluid comprising dissolved CO2 and CO2 microbubbles and/or CO2 nanobubbles in the geological formation, hydraulic fracturing the geological formation, and acidizing the geological formation with the acidic fracturing fluid, thereby increasing a permeability of the geological formation, and wherein the method may be applied for the purposes of geothermal energy harvesting, hydrogen production, hydrocarbon production, economic element extraction, waste disposal, as well as any other extraction, injection, disposal operations of economic interest, or combinations thereof.