About: http://webisa.webdatacommons.org/374663137

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	A suitable gas such as air, nitrogen, carbon dioxide or natural gas may then be passed through the sand or gravel pack to vaporize the solvent, leaving the viscous bituminous petroleum in the sand or gravel pack.
http://www.w3.org/ns/prov#wasQuotedFrom	google.ca