Oil Well Cement Additive Composition for High-Temperature Fluid Loss
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Solution Overview
Problem
Existing fluid loss reducing agents, particularly PVA, fail to provide adequate performance under high temperature and high pressure conditions in oil well cementing, leading to reduced fluidity and increased costs.
Innovation Solution
A vinyl alcohol polymer additive is used, derived from copolymerization of a vinyl ester monomer and a multifunctional monomer, with controlled saponification and viscosity-average polymerization, and specific particle size distribution, to enhance fluid loss reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of fluid loss reducing agent (PVA) is increased to improve fluid loss reducing performance under high temperature and high pressure, then fluid loss reduction is improved, but fluidity of the cement slurry decreases and cost increases
Solution Approach 1:
The patent changes the chemical parameters of the fluid loss reducing agent by specifying a degree of saponification of 75-85 mol% and a viscosity-average polymerization degree of 2800-4500 for the PVA. These parameter optimizations allow achieving better fluid loss reduction performance without requiring excessive amounts of additive, thereby maintaining cement slurry fluidity and controlling costs.
Solution Approach 2:
The patent uses copolymerized PVA combining vinyl alcohol units with specific proportions of acetate groups (15-25 mol%) and formate groups (10-30 mol%). This composite structure creates synergistic effects that enhance fluid loss reduction performance while maintaining compatibility with cement slurry fluidity requirements.
2Reliability
If the amount of fluid loss reducing agent (PVA) is increased to improve fluid loss reducing performance under high temperature and high pressure, then fluid loss reduction is improved, but cost increases
Solution Approach 1:
The patent optimizes the chemical parameters of PVA (degree of saponification: 75-85 mol%, viscosity-average polymerization degree: 2800-4500) to maximize fluid loss reduction efficiency per unit mass. This allows achieving required performance with smaller amounts of additive, reducing material costs while maintaining effectiveness under high temperature and high pressure conditions.
Solution Approach 2:
The copolymerized PVA structure with controlled compositions of acetate and formate groups creates a more efficient fluid loss reducing agent that delivers better performance at lower dosages compared to conventional PVA, thereby reducing the quantity required and associated costs.
3Quantity of substance
If conventional PVA is used as fluid loss reducing agent, then cost is controlled, but fluid loss reducing performance is insufficient under high temperature and high pressure
Solution Approach 1:
The patent specifies precise parameter ranges for PVA: degree of saponification of 75-85 mol% and viscosity-average polymerization degree of 2800-4500. These optimized parameters enhance the molecular structure's ability to resist fluid loss under high temperature and high pressure, achieving superior performance while maintaining cost-effectiveness through efficient dosing.
Solution Approach 2:
The copolymerized PVA containing vinyl alcohol, acetate, and formate groups in specific proportions creates a composite polymer structure with enhanced thermal and pressure stability. This composite structure provides superior fluid loss reduction performance under extreme conditions compared to conventional PVA, while the optimized composition ensures cost efficiency.
Data Source
AI summary
Provided is an additive for oil well cement, containing a vinyl alcohol polymer, the additive having good fluid loss reducing performance. The additive for oil well cement is a saponified product of a copolymer of a vinyl ester monomer and a multifunctional monomer, and has a degree of saponification of 70 to 95 mol% and a viscosity-average degree of polymerization of 1000 to 10000.