Dense CO2 Plugging Agents for Water Channeling in Oil Wells
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Solution Overview
Problem
The challenge in subterranean resource well drilling is the inefficient recovery of hydrocarbons due to channeling of injection fluids through high permeability zones, leading to poor sweep efficiency and excessive water production, which complicates operational management and increases costs.
Innovation Solution
The method involves injecting a dense carbon dioxide composition, comprising dense carbon dioxide and a thickener soluble in the dense carbon dioxide, into high permeability zones to block pores and fractures, thereby reducing water production and enhancing hydrocarbon recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water flooding is used to enhance hydrocarbon recovery, then hydrocarbon production increases, but water production becomes excessive and sweep efficiency deteriorates due to channeling through high permeability zones
Solution Approach 1:
The patent applies local quality by injecting dense carbon dioxide specifically into high permeability zones to create localized plugging effects. This targeted approach modifies the flow properties in specific regions (high permeability zones) without affecting the entire formation, thereby improving sweep efficiency by redirecting water flood through previously bypassed low permeability zones while maintaining hydrocarbon production from treated zones.
2Reliability
If dense carbon dioxide is injected into high permeability zones, then water production is reduced and sweep efficiency improves, but the carbon dioxide may breakthrough at the production well due to insufficient viscosity
Solution Approach 1:
The patent employs composite materials by combining dense carbon dioxide with a thickener to create a composite injection composition. The thickener increases the viscosity of the dense carbon dioxide, providing sufficient resistance to prevent early breakthrough at the production well while maintaining the plugging effectiveness in high permeability zones. This composite approach resolves the contradiction between achieving good sweep efficiency and preventing carbon dioxide loss through breakthrough.
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 effectively reduces water production, improves sweep efficiency during water flooding, and increases hydrocarbon recovery, while also providing a beneficial use for CO2 that helps mitigate global warming.
Implementation Method 1
the dense carbon dioxide composition comprises dense carbon dioxide and a thickener soluble in the dense carbon dioxide
Implementation Method 2
injecting a dense carbon dioxide composition from a production well into the high permeability zone... The dense carbon dioxide composition may block pores, fractures, or both in the high permeability zone
Data Source
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AI summary
A method for reducing water production from a hydrocarbon bearing subterranean formation includes identifying a high permeability zone in the formation and injecting a dense CO2 composition from a production well into the high permeability zone. The dense CO2 composition includes dense CO2 and a thickener soluble in the dense CO2. The thickener includes a copolymer that is the polymerized reaction product of monomers that include at least one alkenyl ether or dialkenyl ether monomer, at least one acrylate or methacrylate monomer, at least one structural monomer, and at least one allyl ester monomer. After injecting the dense CO2 composition into the high permeability zone, the method includes withdrawing hydrocarbons from the hydrocarbon bearing subterranean formation through the production well. The dense CO2 composition blocks pores in the high permeability zone to reduce or prevent flow of water from the high permeability zone into the production well.