Development of Multiple Crosslinked Polymers and Its Application in Synthetic-Based Drilling Fluids

Area of Science:

• Materials Science
• Petroleum Engineering
• Polymer Chemistry

Background:

• Synthetic-Based Drilling Fluids (SBDF) face performance limitations in deep wells and high-temperature conditions.
• Existing fluids struggle with thermal stability, rheology, and filtration control under extreme downhole environments.

Purpose of the Study:

• To engineer a novel multiple hydrogen-bonded crosslinked polymer (MBAH/nano-SiO2) to overcome SBDF performance challenges.
• To enhance the thermal stability, rheological properties, and colloidal stability of SBDF for demanding applications.

Main Methods:

• Synthesis of a crosslinked polymer using methyl methacrylate (MMA), butyl methacrylate (BMA), acrylic acid (AA), N-hydroxyethyl acrylamide (HEAA), and nano-silica (nano-SiO2).
• Characterization of the polymer's properties including crosslinking density, thermal behavior, particle size, and colloidal stability.
• Evaluation of the polymer's performance in W/O emulsions, assessing rheology, electrical stability (ES), and high-temperature/high-pressure filtration loss.

Main Results:

• The synthesized polymer significantly improved crosslinking density and thermal properties.
• A 'weak gel' structure was developed in W/O emulsions, enhancing rheology and electrical stability (ES) up to 775 V at 180 °C.
• High-temperature and high-pressure filtration loss was reduced to 7.6 mL, improving wellbore stability and reservoir protection.

Conclusions:

• The novel MBAH/nano-SiO2 polymer effectively addresses performance challenges in SBDF for deep, high-temperature wells.
• The multiple hydrogen-bonded crosslinking strategy and synergistic nano-SiO2 effect are key to enhanced emulsion stability and reduced filtration.
• This research offers valuable insights for optimizing polymer design in SBDF for improved drilling efficiency and safety.