Microbial Viscosity Breaker Compositions for Slickwater Fracturing
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Solution Overview
Problem
The persistence of polyacrylamide polymers in slickwater fracturing treatments leads to permeability plugging, bacterial growth, and disposal issues, and existing biocides are incompatible with oxidizing viscosity breakers, necessitating an effective biocidal viscosity breaker system.
Innovation Solution
A well treatment composition combining tetrakis(hydroxyorgano)phosphonium salts, quaternary ammonium compounds like benzalkonium chloride, and oxidizing viscosity breakers such as hydrogen peroxide, sodium persulfate, and encapsulated ammonium persulfate, which are compatible and effective in reducing viscosity and controlling microbial populations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If polyacrylamide polymers are used to reduce pumping pressure, then frictional drag is reduced, but polymer residue plugs permeability and promotes bacterial growth
Solution Approach 1:
The patent applies parameter changes by using oxidizing viscosity breakers (hydrogen peroxide, sodium persulfate, ammonium persulfate) to chemically degrade the polyacrylamide polymer chains, changing their molecular weight and viscosity characteristics. This breakdown transforms the harmful persistent polymer residue into smaller, less harmful fragments that don't plug permeability as severely
Solution Approach 2:
The patent converts the harmful effect of polymer persistence into a benefit by deliberately introducing controlled oxidation. The oxidizing agents break down the polymer structure to eliminate plugging and bacterial growth issues while still maintaining sufficient viscosity reduction during the fracturing operation
2Object-generated harmful factors
If biocides are added to control microbial populations, then bacterial growth is controlled, but oxidizing biocides are incompatible with oxidizing viscosity breakers
Solution Approach 1:
The patent uses non-oxidizing biocides (quaternary ammonium compounds, tetrakis hydroxymethyl phosphonium salt) as intermediaries that are compatible with the oxidizing viscosity breakers. These biocides effectively control microbial populations without reacting incompatibly with the oxidation system, serving as a bridge between the two functional requirements
Solution Approach 2:
The patent changes the type of biocide used from oxidizing to non-oxidizing varieties, specifically selecting quaternary ammonium compounds and phosphonium salts that have different chemical mechanisms. This parameter change in biocide selection allows simultaneous use with oxidizing viscosity breakers without incompatibility issues
3Force
If oxidizing viscosity breakers are used to reduce viscosity, then polymer breakdown is achieved, but compatibility with biocides is compromised
Solution Approach 1:
The patent converts the potential harm of oxidizer-biocide incompatibility into a benefit by selecting specific non-oxidizing biocides that are known to be compatible with oxidizing environments. This allows the oxidizing viscosity breaker to function fully while the biocide maintains its effectiveness without being neutralized by oxidation
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 composition effectively reduces viscosity and controls microbial populations without incompatibility, enhancing the biocidal properties and ensuring the stability of the treatment fluid, thereby improving the efficiency and safety of slickwater fracturing processes.
Implementation Method 1
oxidizing viscosity breakers such as hydrogen peroxide, sodium persulfate, and encapsulated ammonium persulfate
Implementation Method 2
tetrakis(hydroxyorgano)phosphonium salt, a quaternary ammonium salt, and at least one oxidizing viscosity breaker, wherein the quaternary ammonium compound is benzalkonium chloride
Data Source
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AI summary
A well treatment fluid composition that includes a tetrakis(hydroxyorgano)phosphonium salt and at least one oxidizing viscosity breaker. Methods for preparing a microbial viscosity breaker composition and treating a subterranean formation are also presented.