Texaco Inc.

Deutsche Texaco Aktiengesellschaft

Walter H Carter

Charles A Christopher

Thomas Jefferson

Jerry L Sides

Karl-Heinz Grodde

Cedric A Nix

Disclosed is a tracer fluid for use in connection with surfactant waterflooding or other chemicalized enhanced oil, recovery processes, and an oil recovery process using the fluid. Fluids containing easily identifiable components such as water-soluble, inorganic salts, specifically water-soluble nitrate salts, as well as low molecular weight alcohols may be used as tracer fluids for determining numerous flow and formation conditions between injection wells and production wells. Many of the most desirable tracers are degraded by bacteria present in field water or surface contamination. Incorporation of from 10 to 2000 and preferably from 50 to 1500 parts per million of an aromatic treating compound, preferably benzene, toluene, or xylene, stabilizes the chemical tracer against microbial attack.

Tracer fluids for enhanced oil recovery

Disclosed is an improved viscous, aqueous, hydrophilic polymer-containing fluid suitable for injection into porous media such as subterranean petroleum-containing earth formations and an oil recovery method in which the aqueous fluid is injected into the subterranean petroleum-containing formation. The fluid contains an effective amount of an aromatic treating substance, preferrably benzene, toluene, xylene, and low alkyl-substituted benzene or toluene. The improvement resulting from incorporation of this additive in the polymer fluid includes greatly increased resistance to microbial degradation of the polymer, improved screen factor, and improves the injectivity of the fluid.

Polymer-containing fluid and an oil recovery method using the fluid

The oil recovery effectiveness of an enhanced oil recovery method comprising sequentially injecting into a subterranean formation, an aqueous, surfactant-containing fluid followed by an aqueous, hydrophilic, viscosity-increasing polymer-containing fluid, is improved by incorporating from 10 to 500 parts per million of an aromatic compound such as toluene in the aqueous polymer-containing fluid.

Enhanced oil recovery method

Disclosed is a tracer fluid for use in connection with surfactant waterflooding or other chemicalized enhanced oil recovery processes, and an oil recovery process using the fluid. Fluids containing easily identifiable components such as water-soluble, inorganic salts, specifically water-soluble nitrate salts, as well as low molecular weight alcohols may be used as tracer fluids for determining numerous flow and formation conditions between injection wells and production wells. Many of the most desirable tracers are degraded by bacteria present in field water or surface contamination. Incorporation of from 10 to 2000 and preferably from 50 to 1500 parts per million of an aromatic treating compound, preferably benzene, toluene, or xylene, stabilizes the chemical tracer against microbial attack.

Method of using tracer fluids for enhanced oil recovery

An adapter for a sensitive viscometer. It provides increased drag at low shear rates to increase the accuracy. There is an inverted cup shaped rotor that cooperates with an annular shaped stationary container for the fluid to be measured. The annular shape of the container provides reaction surfaces with the fluid on both the inner and outer surfaces of the rotor. And, there is a reservoir in the stationary container with an overflow edge, so that the quantity of fluid to be measured is accurately metered.

Adapter for a sensitive viscometer

Method for imparting superior viscosity to an aqueous polysaccharide solution comprises prehydrating polysaccharide in fresh and deionized water. The viscosity imparted to the final aqueous solution by this method is greater than the viscosity of an aqueous polysaccharide solution initially hydrated in hard water. Alternatively, the polysaccharide solution in fresh water may be used alone or diluted with water containing inorganic ions.

Imparting superior viscosity to aqueous polysaccharide solutions

The specification discloses a process for recovering oil from a subterranean reservoir which process utilizes a thickened flooding liquid containing polysaccharide B-1459. In the process the polysaccharide B-1459 is imparted with superior viscosity by first prehydrating it with fresh or deionized water before mixing with another aqueous component, for example brine water containing large amounts or inorganic ions, that is, hard water. The invention comprises the polysaccharide B-1459 which has been prehydrated in the fresh or deionized aqueous medium and then mixed with hard water. The process for imparting viscosity to polysaccharide B-1459 is an improvement over the prior art in that a higher viscosity is obtained while using the same amount of polysaccharide that has been obtained by hydrating the polysaccharide in hard or brine water initially.

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Houston, TX, United States of America

Walter H Carter