Chitin-Based Amphiphobic Nanocomposites for Maintaining Wellbore Stability of Oil-Based Drilling Fluid
Hongyan Du, Kaihe Lv, Mei‐Chun Li, Jinsheng Sun, Xianbin Huang, Yuan Geng, Haokun Shen, Yecheng Li, Muhammad Arqam Khan
Abstract
Drilling fluid additives that maintain wellbore stability have attracted considerable attention because of the frequent occurrence of wellbore instability accidents during drilling operations. However, achieving long-term wellbore stability in practical applications remains challenging. Herein, we report the application of chitin-based amphiphobic nanocomposites (PFTMS@ChNCs/SiO 2 ) to maintain the wellbore stability of oil-based drilling fluids (ODFs). The PFTMS@ChNCs/SiO 2 was prepared using a template approach, generating silica shells on the surface of chitin nanocrystals via the sol–gel method, followed by modification with 1 H,1 H,2 H,2 H -perfluorooctyltrimethoxysilane (PFTMS). The PFTMS@ChNCs/SiO 2 exhibited excellent thermal and chemical stability; even after heating in hot air at 200 °C for 24 h or soaking in hot fluids at 150 °C for 7 d, the contact angle of water and oil on the PFTMS@ChNCs/SiO 2 remained above 120°, making them suitable for the harsh drilling fluid conditions. The shale treated with PFTMS@ChNCs/SiO 2 demonstrated remarkable liquid-repelling properties and maintained good mechanical strength even after prolonged immersion in high-temperature fluids. Moreover, incorporating PFTMS@ChNCs/SiO 2 into ODFs improved their performance, including enhanced rheological properties, better filtration control, and improved mud cake quality. Filtration tests showed a 39.6% reduction in fluid loss, whereas the filtration medium permeability decreased to 0.211 × 10 –4 mD. This study presents a promising method for wellbore stabilization in ODFs and a direction for chitin nanocrystals in oil and gas engineering applications.