A Novel Amphoteric Ion-Modified, Styrene-Based Nano-Microsphere and Its Application in Drilling Fluid

Area of Science:

• Petroleum Engineering
• Materials Science
• Nanotechnology

Background:

• Deep oil and gas exploration faces challenges from high-temperature and high-salinity formations.
• Conventional drilling fluid agents fail under these harsh conditions, risking wellbore collapse and accidents.
• Development of robust drilling fluid additives is crucial for deep resource extraction.

Purpose of the Study:

• To develop a novel drilling fluid agent resistant to high temperatures and salinity.
• To evaluate the performance of a styrene-based nano-microsphere (SSD) modified with amphoteric ions.
• To assess the impact of SSD on drilling fluid properties and wellbore stability.

Main Methods:

• Synthesis of styrene-based nano-microspheres (SSD) with amphoteric ion modification.
• Characterization of SSD particle size (228 nm) and stability at 200 °C and saturated NaCl.
• Evaluation of SSD's salt-responsive properties and plugging efficiency in NaCl solutions.
• Assessment of SSD's effect on drilling fluid rheology, zeta potential, and filtration under simulated downhole conditions.

Main Results:

• SSD demonstrated excellent thermal stability (up to 200 °C) and salt tolerance (up to saturation).
• SSD exhibited significant salt-responsive behavior, with its dispersion becoming transparent in saline solutions.
• Core plugging efficiency reached 95.2% in NaCl solutions, outperforming anion-modified microspheres.
• SSD improved drilling fluid stability, rheology, and filtration reduction by promoting particle gradation and enhancing zeta potential.

Conclusions:

• The developed amphoteric ion-modified styrene-based nano-microsphere (SSD) is a promising agent for high-temperature and high-salinity drilling environments.
• SSD offers superior plugging performance and enhances overall drilling fluid properties, mitigating risks of wellbore instability.
• This research provides a new avenue for developing advanced drilling fluid agents for challenging deep oil and gas exploration.