| 摘要 |
<p>1470855 Recovering oil SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 4 June 1974 24681/74 Heading E1F The percentage of oil recovered from an underground fractured, e.g. limestone formation is increased by introducing carbon dioxide into the formation. The carbon dioxide may be applied in the gaseous form in either a pure state or mixed with another gas, e.g. methane or ethane; dissolved in a liquid, e.g. water; or in situ by injecting oxygen into the formation and allowing combustion of the oil with the oxygen. The carbon dioxide may be introduced into a natural or artificially formed gas cap at any level or into the fractures within the oil filled region of the formation. The rate of introduction of the carbon dioxide into the formation is preferably insufficient to substantially increase the pressure within the fractures.</p> |
