Degradable Proppant Sealing for CO2 Storage Wells
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Solution Overview
Problem
Current CO2 geologic sequestration technology faces challenges such as failure of geologic formations to contain CO2 due to cement degradation, leading to potential catastrophic releases of CO2.
Innovation Solution
A method for storing CO2 in deep underground formations using hydraulic fracturing to create fractures, injecting proppant to maintain fracture patency, and subsequently degrading the proppant with an acidic solution to allow geologic forces to seal the fractures, thereby preventing CO2 escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement is used to cap wells for CO2 storage, then well sealing is achieved, but cement degradation occurs leading to CO2 leakage
Solution Approach 1:
The invention removes the cement capping component from the well sealing system and replaces it with a degradable proppant-based seal. The proppant is injected into the wellbore annulus where it degrades over time, allowing the well to seal naturally without relying on cement durability against CO2 degradation.
Solution Approach 2:
The proppant is designed as a temporary, degradable material that serves its sealing function during the critical storage period and then degrades to allow well closure. This disposable approach eliminates the need for long-term cement durability, as the proppant naturally degrades and the well seals itself.
2Quantity of substance
If proppant is injected to maintain fracture patency for CO2 injection, then CO2 storage capacity is improved, but fracture sealing is compromised leading to potential CO2 escape
Solution Approach 1:
The proppant material is designed with dynamic properties that change over time - initially maintaining fracture patency for CO2 injection, then degrading to allow fracture sealing. This temporal dynamic behavior enables the same material to serve both functions at different stages of the storage process.
Solution Approach 2:
The degradable proppant provides temporary structural support and fracture patency during the critical injection and initial storage period, cushioning against the risk of premature fracture closure. As the proppant degrades, it naturally transitions to allowing seal formation, providing beforehand protection against containment failures.
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 method effectively reduces the risk of long-term CO2 leakage by ensuring that fractures are sealed, providing a permanent and large-scale solution for CO2 storage.
Implementation Method 1
injecting a solution into the formation, the solution capable of at least partially degrading the structural integrity of the proppant positioned within the formation
Implementation Method 2
fracturing the formation, thereby forming fractures
Implementation Method 3
allow geologic forces to seal the fractures
Data Source
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AI summary
Disclosed subject matter includes a system and method for the permanent storage of C02 by removal of hydrocarbons such as natural gas and methane from a geologic formation, combustion to provide de-carbonized electricity, and introduction of carbon-containing compounds such as C02into the geologic formation. Such a sequestration method includes storing carbon compounds in an underground geologic formation by introducing the carbon dioxid into a well formed in the formation by hydraulic fracturing, and closing the fractures by degrading the proppant in the fractures so as to cause resealing of the fractures by geologic forces so as to prevent escape of stored C02 from the formation through the hydraulic fractures and well.