Integrated method for extracting nickel and vanadium compounds from oils

This invention is an integrated process for removing nickel and vanadium metalloporphyrinic compounds from oils which contain them and regenerating the solvent used to extract those metal compounds. The process involves the extraction of those compounds using certain solvents which are not miscible with the oils involved and which preferably are defined using variables known as three-dimensional solubility parameters. The solvents are regenerated for recycle to the extraction step. The most preferred solvents which meet the disclosed criteria are ethylene carbonate, propylene carbonate, ethylene trithiocarbonate and dimethylsulfone. The process is particularly suitable for removing the nickel and vanadium compounds from heavier oils such as crude oils and the so-called gas oils obtained during the early stages of the refining process.