FIELD: chemistry.
SUBSTANCE: invention relates to working fluid media for use in underground operations. The method of processing an underground formation involves preparation of a working fluid medium containing carbon dioxide and a hydrocarbon mixture containing at least approximately 65% hydrocarbons having from six carbon atoms (C6) to eleven carbon atoms (C11), which has Reid vapour pressure below approximately 2 feet per square inch and contains less than approximately 1% hydrocarbons having more than ten carbon atoms (C10) and less than approximately 1% hydrocarbons having less than seven carbon atoms (C7), and putting the said medium into the underground formation. The underground working fluid medium is given above. Method for hydraulic fracturing an underground formation involves putting hydraulic fracturing fluid which contains carbon dioxide and the hydrocarbon mixture given above into the underground formation at pressure sufficient for creating at least one fracture. The method of putting gravel packing involves preparation of a gravel packing composition containing gravel particles, carbon dioxide and the said hydrocarbon mixture, and putting the composition into the well shaft with formation of a packing. The method of drilling in an underground formation involves preparation of a drill fluid containing carbon dioxide and the said hydrocarbon mixture, and drilling to form a well shaft which penetrates the production formation. The invention is developed in subclaims of the formula of invention.
EFFECT: more efficient processing of an underground formation.
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