METHOD FOR EXTRACTING CRUDE OIL FROM CRUDE OIL RESERVOIRS WITH A HIGH RESERVOIR TEMPERATURE

摘要

The invention relates to a two-stage method for extracting crude oil from crude oil reservoirs that have a reservoir temperature higher than 70°C and a salinity of between 20,000 ppm and 350,000 ppm, in which an aqueous formulation comprising at least one glucan with a β-1,3-glycosidically-linked backbone chain and pendant groups with β-1,6-glycosidic bonds thereto, and with a weight-average molecular weight M_w of 1,5* 10⁶ to 25*10⁶ g/mol, is injected into a crude oil reservoir through at least one injection borehole, and crude oil is removed from said reservoir through at least one production borehole. The aqueous formulation is produced in two stages, an aqueous concentrate of the glucan being produced first and the concentration then being diluted with water on-site to obtain the concentration for use.