PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • Underbalanced drilling techniques typically use a commingled stream of liquid and gas such as nitrogen or carbon dioxide as the drilling fluid.Nevertheless, even when using underbalanced drilling technology, there still is the possibility of damage to the formation.
http://www.w3.org/ns/prov#wasQuotedFrom
  • freepatentsonline.com