摘要 |
An invert emulsion drilling fluid including an oleaginous fluid, wherein the oleaginous fluid is the continuous external phase of the drilling fluid; a non-oleaginous fluid, wherein the non-oleaginous fluid is the discontinuous internal aqueous phase of the drilling fluid containing water and at least one organic or inorganic salt dissolved in the water; and an aqueous-phase viscosifier, wherein the aqueous-phase viscosifier is selected from the group consisting of a biopolymer, a salt tolerant clay, and a synthetic polymer, and wherein the aqueous-phase viscosifier is dispersed in the non-oleaginous fluid in a sufficient concentration to increase a low shear viscosity of the invert emulsion drilling fluid. |