IN SITU SOLVENT FRACTIONATION OF BITUMENS CONTAINED IN TAR SANDS

摘要

Bituminous hydrocarbons are recovered from unconsolidated tar sands by in-place, selective leaching with a hot condensate formed upon contact with hot solvent vapors injected in the formation. The composition and temperature of the vapors are regulated so that a less soluble fraction of the tar is left behind as a residue. This residue does not dissolve in the vapors passing through the already leached portion of the formation and continues to act as a sand-supporting and immobilizing agent. Thus, subsidence of the leached formation and release of sand grains (which tend to interfere with removal of the leachate from the formation) are avoided. Solvent for the process is obtainable by distillation or cracking of the produced bitumens.