Stabilization of modified cellulose in brines at high temperatures
AssigneeMobil Oil Corporation
InventorRalph H. Rygg
Life of this patent
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Abstract
Novel processes are provided for the stabilization of modified celluloses in brine solutions useful for well completion and workover. Copper species are added to such fluids in an amount effective substantially to decrease the rate of decomposition of such cellulose at temperatures above about 225.degree. F.
Claims11
A method for improving the temperature stability of a calcium chloride containing brine solution of hydroxyethyl cellulose comprising adding to said solution a member selected from the group consisting of copper metal, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, and cuprous sulfide, in an amount sufficient to decrease substantially the rate of decomposition of said hydroxyethyl cellulose in said brine solution at temperature above about 225.degree. F.
In a well completion or workover process employing a calcium chloride containing brine solution of hydroxyethyl cellulose, the improvement comprising adding to said solution a member selected from the group consisting of copper metal, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, and cuprous sulfide, in an amount sufficient substantially to decrease the rate of decomposition of said hydroxyethyl cellulose in said brine solutions at temperatures above about 225.degree. F.
A method for producing a well completion or workover fluid comprising:
- providing water having a known amount of a member selected from the group consisting of copper metal, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, and cuprous sulfide,
- dissolving in said water calcium chloride,
- dissolving in said water hydroxyethyl cellulose capable of increasing the viscosity of said fluid
- and,
- increasing the amount of said member selected from the group consisting of copper metal, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, and cuprous sulfide, of said water to provide therein an amount of said member sufficient to decrease substantially the rate of decomposition of said hydroxyethyl cellulose in said fluid at temperatures above about 225.degree. F.
A wall completion or workover fluid comprising:
- an aqueous solution, calcium chloride, a hydroxyethyl cellulose capable of increasing the viscosity of said fluid, and an amount sufficient to decrease substantially the rate of decomposition of said hydroxyethyl cellulose at temperatures above about 225.degree. F. of a member selected from the group consisting of copper metal, cuprous chloride, cupric chloride, cuprous bromide, and cuprous sulfide.
Dependencies are inferred from the claim text.