Wellbore Stability through Novel Catechol-Chitosan Biopolymer Encapsulator-Based Drilling Mud

Area of Science:

• Materials Science
• Petroleum Engineering
• Biotechnology

Background:

• Wellbore stability is critical for oil and gas exploration, directly impacting drilling efficiency and safety.
• Marine mussel adhesive proteins, rich in catechol groups, offer inspiration for developing advanced rock-binding materials.
• Existing solutions for wellbore instability often face limitations in harsh deep-water drilling environments.

Purpose of the Study:

• To synthesize a novel catechol-chitosan biopolymer (SDGB) for enhanced wellbore stability.
• To evaluate the performance of SDGB as an encapsulator in water-based drilling fluids (WBDF).
• To compare the chemical enhancing wellbore stability performance of SDGB against other encapsulators.

Main Methods:

• Synthesis of catechol-chitosan biopolymer via Schiff base-reduction reaction.
• Characterization of the biopolymer's molecular structure, including aromatic rings, amines, and catechol groups.
• Assessment of shale inhibition, rock mechanical properties (tension shear strength, uniaxial compression strength), and WBDF properties (rheology, filtration) under simulated drilling conditions.

Main Results:

• The synthesized catechol-chitosan biopolymer exhibited a high shale recovery rate, indicating strong shale inhibition.
• Rocks treated with the biopolymer showed significantly improved tension shear strength and uniaxial compression strength.
• The WBDF containing the biopolymer maintained stable rheological and filtration properties after hot rolling, demonstrating excellent thermal stability and compatibility.

Conclusions:

• The novel catechol-chitosan biopolymer (SDGB) effectively enhances wellbore stability by strengthening rock formations and inhibiting shale swelling.
• SDGB's ability to chelate metal ions contributes to its adhesive, inhibitive, and blockage properties, making it a promising additive for water-based drilling fluids.
• This bio-inspired material offers a sustainable and effective solution for improving drilling operations in challenging geological conditions.