EOR Composition for Low Permeability Formation Recovery
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Solution Overview
Problem
Conventional oil recovery methods face challenges in low or variable permeability formations, leading to unrecovered oil reserves due to decreased formation pressure and the limitations of gas and water injection techniques, which often result in inefficient oil extraction and environmental concerns.
Innovation Solution
An environmentally-friendly composition and method using a chelating agent, biosurfactant, and carbonate salt, combined with a pH adjuster, to enhance oil recovery by repressurizing the formation, reducing interfacial tension, and increasing permeability through controlled gas release and solubilization of scale and carbonate rock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If waterflooding is used to increase reservoir pressure, then oil displacement is enhanced, but injected fluids flow preferentially along highly permeable layers and bypass oil-saturated areas, reducing recovery efficiency
Solution Approach 1:
The composition is designed to selectively interact with different zones in the reservoir. The chelating agent targets scale deposits in low permeability zones, while the biosurfactant reduces interfacial tension at oil-water interfaces in oil-saturated areas, creating localized effects that improve overall sweep efficiency and prevent preferential flow pathways
Solution Approach 2:
The composition changes key parameters: the chelating agent increases permeability by dissolving scale deposits, the biosurfactant reduces interfacial tension between oil and water, and the carbonate salt provides controlled repressurization through CO2 generation. These parameter changes collectively improve fluid flow distribution and oil displacement
2Productivity
If gas injection is used to repressurize the reservoir, then oil mobilization is enhanced, but the technology is difficult to implement with high costs for gas production, compression, and pumping
Solution Approach 1:
The composition generates its own pressurizing gas (CO2) through the in-situ reaction of carbonate salt with formation acids. This eliminates the need for external gas production facilities, compression equipment, and pumping machinery, significantly reducing device complexity and operational costs while maintaining the ability to mobilize oil through repressurization
Solution Approach 2:
The mechanical system of gas compression and pumping is replaced by a chemical system where carbonate salt reacts with formation acids to generate CO2 gas in-situ. This substitution eliminates complex mechanical equipment while achieving the same repressurization effect needed for oil mobilization
3Productivity
If hydrofracturing is used to alter rock structure in low permeability formations, then flow channels are created, but the formation may still have limited fractures and the process is costly and damaging to the formation
Solution Approach 1:
Instead of mechanically fracturing the formation, the chelating agent chemically dissolves scale deposits, changing the permeability parameter from low to high. This chemical approach increases flow capacity without the formation damage and costs associated with hydrofracturing
Solution Approach 2:
The mechanical hydrofracturing process is replaced by a chemical dissolution process. The chelating agent chemically removes scale deposits that block pores, naturally creating flow channels without mechanical fracture, thereby preserving formation integrity while improving flow capacity
4Productivity
If microorganisms are used for MEOR, then gas production in situ occurs, but biocorrosive metabolites are produced that can damage the formation and equipment
Solution Approach 1:
The harmful biocorrosive metabolites are eliminated by extracting the biological component from the system. Instead of using living microorganisms that produce harmful byproducts, the patent uses abiotic carbonate salt that generates only CO2 gas and benign salts through controlled chemical reaction, maintaining gas production benefits while removing harmful factors
Solution Approach 2:
The patent converts the concept of in-situ gas production from a biological process with harmful side effects to a chemical process with beneficial side effects. The carbonate salt reaction produces CO2 for repressurization while simultaneously providing scale dissolution through the same reaction, turning a single-function approach into a multi-benefit solution without harmful metabolites
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 solution effectively increases recoverable oil reserves by enhancing permeability and reducing interfacial tension, allowing for efficient oil extraction without the environmental risks associated with traditional methods, such as biocorrosive microorganisms and inorganic compound release.
Implementation Method 1
chelating agent... increase of formation permeability through dissolution of scale and solubilization of carbonate rock
Implementation Method 2
dissolution of scale and solubilization of carbonate rock in the formation
Implementation Method 3
reduction of interfacial tension in the formation
Implementation Method 4
delayed production of pressurizing gas, e.g., carbon dioxide, with pH-controlled reaction of a carbonate salt
Implementation Method 5
repressurization of an oil formation
Data Source
AI summary
The present invention provides compositions and methods for enhancing oil recovery from low permeability subterranean formation using three mechanisms: repressurization; reduction of interfacial tension; and increased permeability. The subject compositions comprise a chelating agent, a biosurfactant, a carbonate or bicarbonate salt, water, and a pH adjusting substance, which when applied to an oil-bearing formation according to the methods of the subject invention, allow for controlled release of carbon dioxide within the formation without complicated machinery or gas-producing microorganisms.