Patent ID: 7992654

Claim:
A method employed in a drilling system for varying the density of fluid in a tubular member thereof, said method comprising the steps of: a. introducing at a drilling rig a first fluid having a first density into a first tubular member, such fluid being released from the first tubular member into a wellbore; b. directing flow from the wellbore into a second tubular member; c. introducing a second fluid having a non-gaseous state having a second density different than the first density into a third tubular member; d. combining said flow from the wellbore and second fluid to yield a combination fluid having a density that is defined by a selected ratio of the first fluid and the second fluid, such combination fluid rising through said second tubular member to the drilling rig; e. recovering the combination fluid from the second tubular member; f. separating the recovered combination fluid into a first fluid component having a non-gaseous state and a second fluid component having a non-gaseous state and storing the first fluid component and the second fluid component in separate storage units adjacent said drilling rig.