20130248257 | Drilling Fluid Composition - The invention pertains to a drilling fluid composition comprising:—at least one (per)fluoropolyether oil comprising recurring units of formula —CF(CF3)CF2O— said oil having a kinematic viscosity of 30 to 80 cSt measured according to ASTM D455 standard at 20° C. [oil (E)] and possessing a polydispersity index (PDI) of at least 1.15; and—at least one (per)fluoropolyether phosphate comprising at least one perfluoropolyoxyalkylenic chain and at least one phosphoric acid group, in its acid, amide, salt or ester form [phosphate (P)], to a method for its manufacture and to its use in a drilling rig equipment. | 09-26-2013 |