Modified Particulate Weighting Agents for Subterranean Fluids
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Solution Overview
Problem
Conventional weighting agents for subterranean treatment fluids face challenges such as high viscosity, settling issues, and formation damage due to particle aggregation, especially in oil-based inverse emulsions, where surfactants are weakly linked and compete with other interactions, and the use of gellants increases fluid viscosity undesirably.
Innovation Solution
Modified particulate weighting agents comprising metal oxides covalently linked with hydrophobic polymers like perfluoroalkyl polymers and perfluoropolyethers, which reduce particle aggregation and enhance dispersion, allowing for low viscosity and self-suspension without additional suspending agents, and can be tailored for specific properties and removal in subterranean environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional weighting agents like barite are used to increase fluid density, then the density requirement is met, but the fluid viscosity increases and pumping becomes difficult
Solution Approach 1:
The patent changes the particle size parameter of the weighting agent to submicron dimensions (0.1-1.0 micrometers), which fundamentally alters the rheological properties of the suspension. This size reduction decreases the plastic viscosity and yield point while maintaining the density-increasing function, thereby resolving the contradiction between achieving high density and maintaining pumpability
Solution Approach 2:
The patent creates a composite weighting agent by coating submicron particles with a combination of surfactant and polymer materials. This composite structure provides both dispersion stability (preventing aggregation) and low viscosity, allowing the fluid to meet density requirements while remaining easy to pump
2Quantity of substance
If finely divided metal or carbonate particles are used to increase density, then the density is improved, but the plastic viscosity rapidly increases limiting utility
Solution Approach 1:
The patent applies parameter change by reducing particle size to the submicron range and controlling particle morphology, which non-linearly reduces the contribution to plastic viscosity while maintaining density. The coated composite structure further modifies the particle-fluid interaction to minimize viscosity increase
Solution Approach 2:
The patent introduces surfactant and polymer coatings as intermediary substances between the weighting agent particles and the base fluid. These intermediaries prevent direct particle aggregation and reduce interparticle friction, thereby maintaining low plastic viscosity while allowing high density
3Stability of the object's composition
If gellant such as bentonite is added to stabilize the suspension, then suspension stability is improved, but the fluid viscosity increases undesirably
Solution Approach 1:
The patent uses surfactant and polymer coatings as intermediaries that adsorb onto particle surfaces to provide steric and electrostatic stabilization. This alternative stabilization mechanism achieves suspension stability without requiring additional gellants that would increase bulk fluid viscosity
Solution Approach 2:
The coated particles are designed to be self-stabilizing through their surface modifications. The surfactant-polymer coating provides inherent repulsion between particles, eliminating the need for external gellants and maintaining low viscosity while ensuring suspension stability
4Stability of the object's composition
If submicron particles with surfactant-based coatings are used, then dispersion is improved, but the surfactant adherence is weak and competes with other interactions
Solution Approach 1:
The patent creates a composite coating system where surfactant and polymer are combined. The polymer component provides strong, stable anchoring to the particle surface while the surfactant provides dispersion functionality. This composite structure ensures reliable surfactant adherence while maintaining effective particle dispersion
Solution Approach 2:
The patent merges the functions of surfactant (dispersion) and polymer (adhesion/stabilization) into a single integrated coating system. This combination ensures that the surfactant remains firmly attached to particles while effectively preventing aggregation and maintaining stable dispersion in the base fluid
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 solution provides stable, low-viscosity treatment fluids with reduced formation damage and enhanced dispersion of micronized particles, enabling effective density modulation and easy removal from subterranean formations, with the linked polymers minimizing Van der Waals forces and allowing for stimuli-responsive properties.
Implementation Method 1
the linked polymers minimizing Van der Waals forces
Implementation Method 2
a polymer covalently linked to the particulate metal oxide, the polymer being selected from perfluoroalkyl polymers and perfluoropolyethers
Data Source
AI summary
In subterranean operations, additives used in treatment fluids such as drilling and cementing fluids include weighting agents; a method includes the steps of providing a treatment fluid for use in a subterranean formation comprising a weighting agent, the weighting agent comprising a micronized metal oxide particle and a polymer linked to the metal oxide particle, the method including introducing the treatment fluid into the subterranean formation.