Abstract: A method and system for liquifying natural gas using a cryogenic process is described. The method is well suited for producing high methane purity natural gas which can be used as a vehicle fuel. The invention utilizes residue gas from a cryogenic plant as a natural gas feedstock. The natural gas feedstock is condensed by heat exchange with overhead gas from the demethanizer of the cryogenic plant. In the preferred embodiment of the invention the pressure of the condensed natural gas is reduced to a level at which it can be readily stored and transported by expansion through one or more Joule-Thomson valves.

Abstract: The disclosed invention is a method of recovering hydrocarbons by determining the critical concentrations of various crude oil components to carbon dioxide to achieve first contact miscibility of a mixture of said crude oil components and carbon dioxide with the underground hydrocarbons at formation temperature and a selected pressure substantially lower than first contact miscibility pressure of carbon dioxide with the hydrocarbons; injecting into the formation a premixed transition zone slug comprising carbon dioxide and said crude oil components at said critical concentrations, formation temperature and said selected pressure; and injecting a drive fluid into the formation after the premixed transition zone slug.