Patent ID: 6966392
Filing Date: 2005-11-22
Classification: E21B

Abstract:
1. A method employed at a surface location in well drilling operations for varying the density of fluid in a first tubular member, wherein a second tubular member is run through the first tubular member, said second tubular member used to drill a wellbore and to produce drill cuttings, said method comprising the steps of: (a) introducing a first fluid having a first predetermined density from the surface location into the wellbore via the second tubular member, said first fluid transporting the drill cuttings from the wellbore to the first tubular member; (b) introducing a second fluid in a non-gaseous state, said second fluid having a second predetermined density into the first tubular member for combining with the first fluid and producing a combination fluid having a predetermined density that is defined by a selected ratio of the first fluid and the second fluid, said combination fluid rising to the surface along with the drill cuttings; and (c) removing the drill cuttings from the combination fluid; and (d) separating the combination fluid after the combination fluid has risen to the surface into the first fluid and the second fluid.