GB672789A - Improvements in or relating to a method of treatment of wells - Google Patents

Abstract

672,789. Wells. STANOLIND OIL & GAS CO. May 25, 1949. [May 28, 1948; May 28, 1948; Feb. 19, 1949; Feb. 19, 1949] Nos. 13971/49, 13972/49, 13973/49 and 13974/49. Class 85. In a method of increasing the productivity of earth formations into which a well extends, a low penetrating liquid having a dehydration time of at least 1.5 seconds is injected into the formation and pressure applied until an increase in the rate of liquid injection does not increase the liquid pressure and then increasing the penetration characteristics of the liquid. The pressure may be between 0.57 to 0.85 p.s.i. per foot of depth at depths greater than 4,000 feet. The low penetration characteristics of the liquid may be produced by including a bodying agent to form a gel. Bodying agents may be metallic salts of fatty acids. Examples of low penetrating liquids include, 3-10 per cent of aluminium laurate with aluminium naphthate, oleate, or oleate-linoleate in gasoline, kerosine, gas oil, or crude oil; lard, fish oil, cottonseed oil, or chlorinated hydrocarbons containing high molecular weight linear molecules or polymers or rubber ; aqueous liquids containing hydrated starch or water-soluble soaps, particularly for use with brine or waterwells; cobalt-aluminium soaps of fatty acids containing at least 12 carbon atoms and having at least one carboxylic group in chain linkage e.g. stearic, oleic, or palmitic acid or the acid radicles of coconut, pea-nut or palm oils. The liquid may be pumped in before gel formation is complete and may also contain granular material, e.g. sand, to act as props to keep the broken formation open. The gel may be broken by a solvent, e.g. for a hydrocarbon liquid, carbon tetrachloride or carbon disulphide ; for diluted pitch, benzene; for hydroxy aluminium soaps, an amine or an oil soluble sulphonate. 1 per cent of a peptiser may be incorporated in a gel solution and may break the gel after a time delay. The bodying agents may be used in liquids which dissolve waxes or gums or a constituent of the formation ; in the latter case acids may be used with gums, e.g. kauri or copal, as the bodying agent. Packers may be placed in the well above and below the formation to be broken, the low penetrating liquid pumped in, pressure applied by pumping in another liquid, e.g. crude oil,.the well sealed for some time, then a gel breaker may be pumped in and the well produced.