GB1021528A - Method for treating a part of a permeable formation - Google Patents

Abstract

1,021,528. Wells; consolidating earth. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. March 26, 1964, No. 12985/ 64. Heading E1F. In a method of consolidating part of a permeable formation penetrated by a borehole and comprising injecting through the borehole a slug of liquid suitable for displacing water and containing a solvent having an "organo functional silane" dissolved therein, then injecting through the borehole a second slug of liquid suitable for displacing the solvent and having a second solvent containing a resin-forming composition dissolved therein, and retaining the second solvent in the part of the formation until a hard cross-linked resin has been formed, one of the slugs is suitable for displacing oil. The "organo functional silane" means an organic substance containing a silicon atom, a functional group suitable for reacting with the particles of the formation and a functional group suitable for reacting with one of the components of the resin forming composition or the product formed thereby. The silane has an amino, epoxy, methoxy or ethoxy group reacting with the resin-forming composition or product and is at most 1 vol.% of the solution. The resin-forming composition may be uncured resin such as a polyepoxide having o / \ more than one epoxy group -c - c- || per molecule, and a curing agent such as a polyamine compound containing at least three amino-hydrogen atoms, or the polyepoxide and a substance formed by reacting the polyepoxide with a curing agent, or a hydroxyaryl compound and an aldehyde. The resin-forming composition is from 3-50 vol. per cent of the solution, the amount determining whether the walls of the formation pores are coated or whether the pores are filled with resin. The leading part of the first slug may be a pre-flush liquid suitable for displacing the water, or the solvent in the first slug may be suitable for displacing the water. The pre-flush liquid may be liquid, such as acetone or an alcohol, which is suitable for driving the oil. When the first slug displaces only water the solvent in the second slug may displace the first solvent and the oils or the spacer liquid at the leading port of the second slug may displace the first solvent and the oil. The quantities of the constituents of the slugs are found by tests on sand packs containing water and oil at the formation temperature and pressure. The second slug is driven down the borehole by mud having plastering properties so that a resin coating is not formed on the walls of the borehole, and the resin deposit is not displaced outwardly from the walls of the borehole. Carbonates deposited on the sand of a formation are removed by acid prior to the treatment consolidation. The method may be applied to formations containing oil only or water only.