N-Vinylpyrrolidone Crosslinked Polymers for High-Temperature Drilling Fluids
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Solution Overview
Problem
Existing drilling fluids face challenges in maintaining viscosity and fluid-loss control at high temperatures, particularly in subterranean formations, where acrylamide-based polymers tend to hydrolyze and lose effectiveness.
Innovation Solution
The use of crosslinked polymers comprising N-vinyl lactam monomeric units, such as N-vinylpyrrolidone, combined with acrylamide-based, acrylate-based, ester-based, or amide-based crosslinkers, which provide improved thermal stability and rheological properties without the need for clay-based additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acrylamide-based polymers are used in drilling fluids, then viscosity and fluid-loss control are improved, but thermal stability deteriorates at high temperatures due to hydrolysis
Solution Approach 1:
The patent changes the chemical composition parameters by replacing acrylamide-based polymers with N-vinyl lactam polymers (such as poly-N-vinylpyrrolidone). This parameter change resolves the contradiction because N-vinyl lactam polymers maintain both fluid-loss control effectiveness and thermal stability at high temperatures, unlike acrylamide-based polymers that hydrolyze and lose effectiveness above 200°F.
Solution Approach 2:
The patent employs composite material strategy by using copolymers containing N-vinyl lactam units combined with other monomer units. This creates a composite polymer structure that achieves both desired rheological properties (for fluid-loss control) and enhanced thermal stability, resolving the contradiction between these two performance requirements.
2Reliability
If traditional acrylamide homopolymers are used, then fluid-loss control is achieved, but viscosity maintenance deteriorates at temperatures above 200°F due to degradation
Solution Approach 1:
The patent changes the polymer chemical structure from acrylamide homopolymer to N-vinyl lactam polymer (specifically poly-N-vinylpyrrolidone). This parameter change extends the duration of viscosity maintenance to at least 48 hours at temperatures up to 300°F, resolving the contradiction by preventing the thermal degradation that limits the duration of action in traditional polymers.
3Reliability
If clay-based additives are used to improve fluid-loss control, then fluid-loss control is enhanced, but device complexity and environmental concerns increase
Solution Approach 1:
The patent extracts and eliminates clay-based additives from the drilling fluid formulation by replacing them with synthetic N-vinyl lactam polymers. This taking out principle resolves the contradiction by removing the complexity and environmental concerns associated with clay additives while maintaining or improving fluid-loss control performance through the synthetic polymer system.
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
These crosslinked polymers maintain desired viscosity and fluid-loss control at temperatures up to 300°F for extended periods, such as 48 hours, without the degradation issues seen with traditional acrylamide homopolymers, ensuring effective drilling fluid performance.
Implementation Method 1
These crosslinked polymers maintain desired viscosity and fluid-loss control at temperatures up to 300°F for extended periods, such as 48 hours, without the degradation issues seen with traditional acrylamide homopolymers
Implementation Method 2
acrylamide-based polymers tend to hydrolyze and lose effectiveness
Data Source
AI summary
Crosslinked polymers that may be useful, for example, as viscosifiers or fluid-loss control additives for well treatment and servicing fluids are provided. In one embodiment, the methods comprise: providing a treatment fluid comprising a base fluid and a crosslinked polymer composition comprising at least one polymer that comprise at least one N-vinyl lactam monomeric unit, and at least one crosslinker selected from the group consisting of: an acrylamide-based crosslinker, an acrylate-based crosslinker, an ester-based crosslinker, an amide-based crosslinker, any derivative thereof, and any combination thereof; and introducing the treatment fluid into at least a portion of a wellbore penetrating at least a portion of a subterranean formation.