Crosslinked Sulfonic Acid Polymer Viscosifier for High-Temperature Drilling Fluids
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Solution Overview
Problem
Conventional viscosifiers used in petroleum extraction face challenges in providing adequate viscosity and fluid loss control at high temperatures and in high-salinity environments, often requiring the use of clay and non-water-soluble weighting agents that can cause formation damage and difficulty in clean-up.
Innovation Solution
A crosslinked viscosifier polymer with an ethylene repeating unit, including an —S(O)2OR1 group, is used to provide effective viscosity and fluid loss control without the need for clay, maintaining stability and performance in high-temperature and high-salinity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If clay and non-water-soluble weighting agents are used to achieve desired viscosity and density, then viscosity and fluid loss control are improved, but formation damage occurs due to pore plugging and clean-up difficulty increases
Solution Approach 1:
The patent changes the chemical composition parameters by using water-soluble polymers instead of clay, and employs water-soluble weighting agents with specific density ranges (4.0-8.0 g/cm³) to achieve the desired rheological properties without formation damage. The polymer concentration and weighting agent density are optimized to maintain viscosity while preventing pore plugging.
Solution Approach 2:
The patent creates a composite drilling fluid system combining water-soluble polymers (such as polyacrylamide, hydroxyethyl cellulose) with water-soluble weighting agents (such as barite, hematite) to achieve the combined benefits of viscosity enhancement and density control without the harmful effects of clay-based systems.
2Strength
If biopolymers are used as viscosifiers in drill-in fluids, then fluid loss control is improved, but temperature limit is restricted below 300° F.
Solution Approach 1:
The patent changes the polymer type parameter from biopolymers to synthetic water-soluble polymers that are specifically selected for their thermal stability at reservoir temperatures exceeding 300° F. The molecular weight and chemical structure of the polymers are optimized to maintain fluid loss control properties under high-temperature conditions.
3Temperature
If synthetic water-soluble polymers are used at temperatures above 300° F., then temperature limit is exceeded, but viscosity and fluid loss control become inadequate due to thermal breakdown
Solution Approach 1:
The patent employs a composite polymer system using copolymers with specific monomer compositions (such as acrylamide-methacrylamide, acrylonitrile-acrylamide) that provide thermal stability. The crosslinked polymer network structure is designed to resist thermal breakdown while maintaining viscosity and fluid loss control properties at high temperatures.
Solution Approach 2:
The patent optimizes the crosslinking degree and molecular weight parameters of the synthetic polymers to enhance thermal stability. The crosslinked structure prevents polymer chain scission at high temperatures, thereby maintaining adequate viscosity and fluid loss control even at temperatures above 300° F.
4Quantity of substance
If heavy brines are used to provide density, then density requirement is met, but polymer thermal breakdown and high salt content continue to challenge viscosity maintenance
Solution Approach 1:
The patent uses a composite system combining specific synthetic polymers (such as partially hydrolyzed polyacrylonitrile, carboxymethyl cellulose) with heavy brines. The polymer selection and concentration are optimized to maintain viscosity stability in high-salinity environments, resisting both thermal breakdown and salt-induced degradation.
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 crosslinked viscosifier polymer achieves superior viscosity and fluid loss control, reducing the risk of formation damage and clean-up difficulties, while maintaining stability and efficiency in high-temperature and high-salinity environments, making it a more versatile and cost-effective option for subterranean treatments.
Implementation Method 1
Various viscosifiers are used with clay in order to achieve a desired viscosity or degree of fluid loss control
Implementation Method 2
The crosslinked viscosifier polymer can be used with water or brine to provide effective increased viscosity and fluid loss control
Data Source
AI summary
Various embodiments disclosed relate to crosslinked polymers including sulfonic acid groups or salts or esters thereof as viscosifiers and fluid loss additives for subterranean treatment. In various embodiments, the present invention provides a method of treating a subterranean formation. The method includes placing in a subterranean formation a composition including a crosslinked viscosifier polymer including an ethylene repeating unit including an —S(O)2OR1 group wherein at each occurrence R1 is independently chosen from —H, substituted or unsubstituted (C1-C20)hydrocarbyl, and a counterion.