PVA Polymer Particle Control for High-Temperature Cement Slurry Fluidity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional polyvinyl alcohol (PVA)-based fluid loss reducing agents fail to maintain fluidity under severe high-temperature and high-pressure conditions in cement slurries, leading to impaired performance and increased costs due to thickening.
Innovation Solution
A polyvinyl alcohol-based polymer with controlled particle size distribution, specifically a particle size of 50 nm or more at a cumulative frequency of 50% and a 1.0 mass % aqueous solution passing through a 300-mesh filter with 95% efficiency and a 0.45 μm filter with 10% or less, is used to enhance resistance to melting at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of conventional PVA-based fluid loss reducing agent is increased to improve fluid loss reducing performance under high temperature and pressure, then the fluid loss reducing effect is enhanced, but the cement slurry thickens causing decreased fluidity and increased cost
Solution Approach 1:
The patent changes the particle size parameter of PVA from conventional large particles to specifically controlled small particles (50 nm or more at cumulative frequency of 50%, with average particle size of 60 nm or more). This parameter change allows the polymer to maintain effectiveness at lower concentrations while avoiding excessive thickening, thus resolving the contradiction between fluid loss reduction and fluidity maintenance.
Solution Approach 2:
The patent creates a composite system by combining PVA with specific particle size distribution characteristics and controlled molecular weight (average degree of polymerization 2500-6000). This composite approach enables the material to achieve both high fluid loss reduction performance and maintained fluidity through optimized structural properties rather than simply increasing concentration.
2Reliability
If the amount of conventional PVA-based fluid loss reducing agent is increased to prevent elution under high pressure, then resistance to melting is improved, but the cost increases due to thickening of cement slurry
Solution Approach 1:
The patent changes the molecular weight parameter by controlling the average degree of polymerization to 2500-6000, and particle size to 50 nm or more at cumulative frequency of 50%. These parameter changes enable the PVA to achieve high resistance to melting and elution at much lower concentrations, thereby reducing the quantity of substance required and lowering costs while maintaining reliability.
3Ease of manufacture
If conventional PVA is used as fluid loss reducing agent, then the cement slurry can be prepared, but the polymer melts at high temperature and is eluted under high pressure causing impaired fluid loss reducing effect
Solution Approach 1:
The patent applies parameter changes by controlling the average particle size to 50 nm or more at cumulative frequency of 50% and average degree of polymerization to 2500-6000. These parameter changes enhance the thermal and pressure stability of PVA, preventing melting and elution under severe well conditions while maintaining ease of slurry preparation.
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 polymer effectively reduces fluid loss in cement slurries under severe conditions, maintaining fluidity and reducing costs by preventing elution and thickening.
Implementation Method 1
particle size distribution by dynamic light scattering measurement of a 0.4 mass % aqueous solution of the polyvinyl alcohol-based polymer
Implementation Method 2
passage rate for a 300-mesh filter (opening: 0.045 mm) and passage rate for a membrane filter having a pore size of 0.45 μm
Data Source
AI summary
A PVA excellent in resistance to melting at high temperature is provided. The polyvinyl alcohol-based polymer is a saponificated product of a homopolymer composed of a vinyl ester monomer, a copolymer of a vinyl ester monomer and a monofunctional monomer other than the vinyl ester, a copolymer of a vinyl ester monomer and a polyfunctional monomer, or a copolymer of a vinyl ester monomer, a monofunctional monomer other than vinyl ester, and a polyfunctional monomer has a particle size of 50 nm or more at a cumulative frequency of 50% in particle size distribution by dynamic light scattering measurement of a 0.4 mass % aqueous solution of the polyvinyl alcohol-based polymer at 25° C.