Supercritical CO2 Polymer Sealing for Subterranean Crack Mitigation
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Solution Overview
Problem
In subterranean hydrocarbon recovery, existing methods fail to effectively reduce the permeability of 'thief zones' and maintain wellbore integrity due to limitations in sealing small cracks and fractures, leading to fluid leakage and inefficient oil/gas extraction.
Innovation Solution
A method involving a composition of a polymer portion, such as polyfluoroacrylate or copolymers with carbon dioxide, is applied under pressure above the cloud point to reduce surface wettability and fluid transport through materials like cement and subterranean formations, effectively sealing cracks and reducing permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing fluids (cement, solids-free resin, water-based coagulating emulsions) are injected to seal cracks and fractures, then wellbore integrity is improved, but the sealing effectiveness deteriorates in very small openings or passages
Solution Approach 1:
The invention changes the physical state and solubility parameters of the polymer by controlling pressure and temperature conditions. The polymer is dissolved in supercritical carbon dioxide at high pressure (above cloud point), creating a low-viscosity solution that can penetrate small cracks. Upon pressure reduction, the polymer precipitates and seals the cracks. This parameter change enables effective sealing of very small openings that conventional fluids cannot address.
Solution Approach 2:
The invention utilizes phase transitions of carbon dioxide between supercritical and gaseous states. CO2 is maintained in a supercritical state during injection to dissolve the polymer, then transitions to a gaseous state during depressurization, causing the polymer to precipitate and form seals. This phase transition mechanism allows the sealing agent to deliver precise polymer deposits in small cracks without leaving residual fluid that could cause leakage.
2Productivity
If flooding operations are conducted in subterranean formations, then hydrocarbon recovery is improved, but fluid transport through thief zones deteriorates causing inefficient extraction
Solution Approach 1:
The invention applies permeability reduction treatment selectively to thief zones rather than the entire formation. By identifying and treating only the high-permeability zones that cause fluid loss, the method maintains efficient flooding operations in productive zones while reducing waste in thief zones. This localized approach preserves overall hydrocarbon recovery efficiency while eliminating fluid loss problems.
Solution Approach 2:
The invention performs preliminary treatment of thief zones before conducting flooding operations. By reducing the permeability of thief zones in advance through polymer injection, the method prevents fluid loss that would occur during subsequent flooding operations. This preliminary action ensures that flooding fluids are directed to productive zones from the start, maximizing hydrocarbon recovery efficiency.
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 significantly reduces fluid leakage and permeability, enhancing wellbore integrity and oil/gas extraction efficiency by sealing small cracks and fractures, even in challenging conditions.
Implementation Method 1
A pressure of the composition is maintained above the cloud point of the polymer portion at a concentration thereof in the carbon dioxide for the period of time
Implementation Method 2
exposing the material to a composition including a solution of a polymer portion and carbon dioxide
Data Source
AI summary
A method of treating a material to achieve at least one of reducing surface wettability of the material or reducing fluid transport through the material includes exposing the material to a composition including a solution of a polymer portion and carbon dioxide for a period of time. The polymer portion includes at least one of a polyfluoroacrylate or a copolymer of a fluoroacrylate and a comonomer. A pressure of the composition is maintained above the cloud point of the polymer portion at a concentration thereof in the carbon dioxide for the period of time.