Method for delaying the setting of and acid-settable liquid in a terrestrial zone
AssigneeChevron Research Company
InventorPatrick H. Hess
Life of this patent
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Abstract
In an improved method for the treatment of a permeable formation or zone adjacent to the bore of an oil well, the setting time of an acid-settable liquid is predictably delayed by use of a novel catalyst system. The method provides an effective means for controlling the reduction of the permeability of the formation or zone in a single stage treatment by dissolving the catalyst in the liquid and introducing the solution into the formation. The catalyst system comprises a mixture of a suitable acid-releasing compound and a base.
Claims6
The method of setting an acid-settable liquid which sets at a temperature in the range from about -10.degree.C. to 175.degree.C. at a pH of less than about 5, which comprises dissolving in said liquid in parts by weight an amount of a delayed latent catalyst in the range from about 2 to 20 parts per 100 parts of the liquid, said catalyst being a mixture of a component which releases a strong acid and a basic component wherein the mixture contains an amount of base in the range from 0.02 to 0.98 equivalent per equivalent of releasable strong acid from the acid-releasing component;
- said liquid being an organic liquid selected from the group consisting of:
- a. acid-settable hydroxylic liquids;
- b. nonhydroxylic acid-settable liquids which contain at least an effective amount of a hydroxylic acid-settable liquid;
- and
- c. nonhydroxylic acid-settable liquids which contain at least an effective amount of a soluble diluent selected from the group consisting of:
- 1. water;
- 2. one or more substantially neutral organic compounds of the formula R(OH).sub.n, in which n is 1, 2 or 3 and R is an organic radical;
- and
- 3. a mixture of the compounds of 2) and water;
- said basic component being one or more suitable bases selected from the group consisting of organic and inorganic salt-forming bases having a pKb of less than about 13.5;
- and said acid-releasing component being one or more substantially neutral compounds selected from the group consisting of organic compounds which release a strong acid under solvolytic conditions at a rate in the range of from about 10.sup.-.sup.3 to 10.sup.-.sup.6 equivalent of the acid per liter per minute at said temperature.
The method of setting furfuryl alcohol which comprises dissolving in said furfuryl alcohol in parts by weight an amount of a delayed latent catalyst in the range from about 2 to 20 parts per 100 parts of the alcohol, said catalyst being a mixture of a component which releases a strong acid and a basic component wherein the mixture contains an amount of base in the range from 0.02 to 0.98 equivalent per equivalent of releasable strong acid from the acid-releasing component;
- said basic component being one or more suitable bases selected from the group consisting of organic and inorganic salt-forming bases having a pKb of less than about 13.5;
- and said acid-releasing component being one or more substantially neutral compounds selected from the group consisting of organic compounds which release a strong acid under solvolytic conditions at a rate in the range of from about 10.sup.-.sup.3 to 10.sup.-.sup.6 equivalent of the acid per liter per minute at said temperature.
Dependencies are inferred from the claim text.