IN-SITU MULTI-STEP STEAM EXTRACTION OF BITUMEN Russian patent published in 2019 - IPC E21B43/24 

FIELD: chemistry.

SUBSTANCE: invention relates to extraction of oil products from heavy oil or bitumen formations of underground deposits. Method of in-situ extraction of oil products from underground heavy oil or bitumen formations involves: (i) drilling one or more wells within an oil-rich zone of a heavy oil or bitumen formation; (ii) injecting first vapour composition into well; (iii) extraction of oil products from well; (iv) injecting into the well a second vapour composition which is different from the first vapour composition; (v) extraction of additional oil products from the well; (vi) optionally repeating one or more injection/production cycles (steps (iv) and (v)), if desired, using third, fourth, fifth and subsequent steam compositions; (vii) making a decision on termination of oil products extraction; (viii) termination of oil product extraction. Each steam composition contains steam and one or several substances increasing oil recovery in amount of 0.01–10 wt. % in respect to total vapour weight and increasing oil recovery substances. Oil-recovery substances are selected from the group: monoethylene glycol monohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monohexyl ether, 2-ethylhexyl ether of monoethylene glycol, 2-ethylhexyl ether of diethylene glycol, 2-ethylhexyl ether of triethylene glycol, 2-propylheptyl ether of monoethylene glycol, 2-propylheptyl ether of diethylene glycol, 2-propylheptyl ether of triethylene glycol or 2-(2-hexoxy-2-ethoxy)-1-aminoethane.

EFFECT: technical result is economically justified increase of oil recovery, increased degree of extraction of bitumen and/or heavy oil.

6 cl, 3 dwg, 1 tbl, 5 ex