METHOD AND GEL-FORMING COMPOSITION FOR PREVENTING PETROLEUM AND PETROLEUM PRODUCTS FROM EVAPORATION FROM TANKS Russian patent published in 1998 - IPC

FIELD: oil and gas production. SUBSTANCE: gel-forming composition ingredients are mixed and composition is foamed to yield gel foam. The latter is directly applied onto oil surface in such a way as to assure gel foam spreading time to be by 3-5 min less than initial composition gel formation time. Density of gel foam is chosen equal to 0.3-0.55 g/cu.cm and thickness of gel foam (h) is determined from relationship: h > 4/ρ where ρ is gel foam density. Gel- forming composition contains, wt %: water-soluble polymer, 0.3-2; nonionic or mixed-type surfactant, 2-4; cross-linking agent, 0.05-0.12; mineral acid salt, 3-10; fresh water, the balance. EFFECT: increased anti- evaporation efficiency. 2 cl, 2 tbl