Water-based lubricating oil for drilling fluid and preparation method of water-based lubricating oil

The invention relates to the technical field of lubricating oil for drilling fluid, and in particular relates to water-based lubricating oil for drilling fluid and a preparation method of the water-based lubricating oil. The water-based lubricating oil is prepared from the following raw materials in parts by weight: 25-35 parts of cotton seed oil, 8-12 parts of methyl ester, 4-6 parts of sodium hydroxide water solution with mass percent of 40%, 50-60 parts of water and 4-6 parts of surfactant. The invention discloses the water-based lubricating oil for drilling fluid and the preparation method of the water-based lubricating oil. When added to water-based or oil-based drilling fluid, the obtained lubricating oil has good compatibility with the drilling fluid, can obviously reduce the sludge cake adhesion coefficient of the water-based or oil-based drilling fluid, improves the flowability of the drilling fluid, reduces annular flow resistance, prevents well wall instability and improves the entrainment property