Research on Environmentally Friendly Palm Oil-Based Drilling Fluids

To address the environmental issues and high treatment costs of conventional oil-based drilling fluids, an environmentally friendly palm oil-based drilling fluid system was developed using palm oil as the base oil. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the main components of palm oil are octadecanoic acid (stearic acid) and tetradecanoic acid (myristic acid). A natural material, humic acid, was selected as the raw material and modified by grafting with octadecylamine to synthesize a loss-control additive that exhibits good compatibility with palm oil. The synthesized loss-control agent was characterized by structural analysis, thermogravimetric analysis, and scanning electron microscopy. Key additives such as organic soil and emulsifiers were optimized to form the environmentally friendly palm oil-based drilling fluid system. The formulation consists of palm oil +20% CaCl2 + 3% organic soil +3% emulsifier +3% loss-control agent +1% wetting agent +1% CaO + heavy crystalline stone. Evaluation of the basic properties, contamination resistance, and environmental performance of the palm oil-based drilling fluid system revealed that before and after aging at 120°C, the system had a demulsification voltage of over 800 V, a high-temperature, high-pressure filtration loss of 5.4 mL, and moderate viscosity and shear rate. The system showed good resistance to NaCl and rock cuttings contamination. The biological toxicity EC50 value of the system was 104,000 mg/L, and the BOD5/CODCr value of the leachate was 24.5%, indicating low biological toxicity and biodegradability. This system meets the environmental requirements for drilling fluids in regions with high environmental standards.