Provided is a lubricant, which may include a mixture of alkyl-esterified fatty acids from waste vegetable oil and a C8/C10 fatty acid blend. The C8/C10 fatty acid blend may include a caprylic fatty acid (C8) and a capric fatty acid (C10). Provided is a method of preparing a lubricant, which may include providing alkyl-esterified fatty acids from waste vegetable oil and a C8/C10 fatty acid blend, and mixing them such that a homogeneous lubricant composition forms. Further provided is a water-based mud, which may include an aqueous base solution and a lubricant composition. Further provided is a method off preparing the water-based mud, which may include providing an aqueous base solution and a lubricant composition and mixing them such that the water-based mud forms. Further provided is a method of using a water-based mud, which may include introducing into a wellbore the water-based mud comprising a lubricant composition.