Patent ID: 9534164
Date: 2017-01-03
CPC Classifications: C04B,C09K

Claim:
1. A method for introducing and positioning a first fluid in a well bore annulus of a well bore containing a second fluid, where the well bore is located beneath a surface, is defined by a well bore wall extending from a surface underground, fluidly couples to a first fluid conduit and a second fluid conduit, and contains at least a portion of a tubular having an exterior surface; where the first fluid conduit and the second fluid conduit each are separately fluidly connected with the surface and are operable to convey fluids between the well bore and the surface; and where the well bore annulus is defined as a portion of the well bore between the tubular exterior surface in the well bore and the well bore wall; the method for introducing and positioning comprising the steps of: formulating a spacer fluid composition, such that a measured viscosity of a mixture of the first fluid and the spacer fluid composition at a first ratio of the first fluid to the spacer fluid composition is less than a measured viscosity of a mixture of the second fluid and the first fluid at a second ratio of the second fluid to the first fluid, where the first ratio and second ratio are substantially the same, and where the second fluid is an oil-based fluid and the first fluid is a water-based cement slurry; formulating the spacer fluid composition, such that a measured viscosity of a mixture of the second fluid and the spacer fluid composition at a third ratio of the second fluid to the spacer fluid composition is less than a measured viscosity of a mixture of the second fluid and the first fluid at the second ratio of the second fluid to the first fluid, where the third ratio is substantially the same as the first ratio and the second ratio, where a measured viscosity of the spacer fluid composition is less than a measured viscosity of the first fluid and a measured viscosity of the second fluid, and where the spacer fluid composition maintains compatibility with both the first fluid and the second fluid during heavy contamination when the volume percent of the spacer fluid composition is about 50% by volume in a mixture comprising the spacer fluid composition, the first fluid at about 25% by volume, and the second fluid at about 25% by volume; introducing into the well bore through the first fluid conduit an amount of the spacer fluid composition such that the spacer fluid composition fluidly couples to the second fluid in the well bore, where the spacer fluid composition comprises a chemically modified tannin at a concentration of about 8.5 pounds per barrel, barite at a concentration of about 377 pounds per barrel, a silicone liquid at a concentration of about 0.1 gallons per barrel, and an ethoxylated alcohol at a concentration of about 1.9 pounds per barrel in an aqueous base fluid and where the spacer fluid composition is compatible with both the first fluid and the second fluid; introducing into the well bore through the first fluid conduit an amount of the first fluid such that the first fluid fluidly contacts the spacer fluid composition in the well bore and the first fluid does not contact the second fluid, where the first fluid and the second fluid are not compatible with one another; and positioning a portion of the first fluid in the well bore annulus, the portion of the first fluid positioned in the wellbore annulus mixing with the spacer fluid composition up to a volume ratio of about 95:5 first fluid to spacer fluid composition, such that the water-based cement slurry compressive strength upon setting to a solid cement is increased by at least about 25% at about 24 hours compared to the water-based cement slurry alone, where during each introduction step an amount of the fluid in the well bore substantially equivalent to the amount of fluid introduced passes from the well bore through the second fluid conduit, and where during each introduction step the fluid in the well bore flows non-turbulently through the well bore annulus.