Aqueous delayed acid system for well stimulation

1. An acidizing composition for use in acidizing a subterranean formation comprising, as a first member, an inorganic or organic acid and, as a second member:

A. an organophosphorus surfactant selected from the group consisting of amino phosphonates and phosphino carboxylates; and

B. an acid retarder of (a) urea or a urea derivative and (b) a bifunctional organic compound comprising (i) at least one quaternary ammonium moiety and at least one —OH group;

wherein the organophosphorus surfactant, in the presence of the acid retarder, is capable of being adsorbed onto a surface of the subterranean formation.

2. A method of treating a subterranean formation penetrated by a well comprising:

(a) stimulating the formation with an acidizing composition comprising:

(i) an organophosphorus surfactant selected from the group consisting of amino phosphonates and phosphino carboxylates; and

(ii) an acid retarder of (a) urea or a urea derivative and (b) a bifunctional organic compound comprising (i) at least one quaternary ammonium moiety and at least one —OH group; and

(b) enhancing permeability of the formation with the acidizing composition.

3. The method of claim 2 , wherein the acidizing composition contains both the organophosphorus surfactant and the acid retarder.

4. The method of claim 2 , comprising pumping the acidizing composition into the well at a pressure sufficient to create or enhance a fracture and reacting the acid with the formation to create conductive channels.

5. The method of claim 2 , comprising pumping the acidizing composition into the well at a pressure lower than that which induces creation of a fracture and creating conductive branched flow channels within the formation.

6. The method of claim 2 , wherein the organophosphorus surfactant has at least one —OH group, at least one alkyl group, a phosphonium group and at least one ammonium group.

7. The method of claim 2 , wherein the organophosphorus surfactant is an ester based phosphobetaine having a quaternized nitrogen.

8. The method of claim 2 , wherein the organophosphorus surfactant is an amino phosphonic acid, a phosphino carboxylate or a phosphino derivatized or partially neutralized phosphinocarboxylate polymer of approximate number average molecular weight from about 500 to 20,000 or an oil soluble blend of a tertiary alkyl amine and an amino phosphonic acid.

9. The method of claim 2 , wherein the bifunctional organic compound contains both quaternary ammonium and an alcohol.

10. The method of claim 9 , wherein the bifunctional organic compound is choline chloride.

11. The method of claim 2 , wherein the bifunctional organic compound is a hydroxyethyl ammonium salt.

12. The method of claim 11 , wherein the bifunctional organic compound is trimethyl hydroxyethyl ammonium chloride.

13. The method of claim 2 , wherein the acidizing composition is an aqueous system comprising from 15 to 30 weight percent urea.

14. The method of claim 2 , wherein the organophosphorus surfactant is an amino phosphonate.

15. The method of claim 14 , wherein the organophosphorus surfactant is an amino phosphonate of the formula (II):

wherein:

R 1 is alkyl or alkylene having between 7 and 21 carbon atoms;

a, b and c are each independently integers ranging from 0 to 20, with the proviso that a+b+c be equal to or greater than 1;

R 2 is selected from the group consisting of alkyl having 7 to 21 carbon atoms and R 3 —C(O)—N(H)—(CH 2 ) 2 — where R 3 is alkyl having 7 to 21 carbon atoms.

16. The method of claim 14 , wherein the organophosphorus surfactant is an amino phospholipid.

17. The method of claim 16 , wherein the phospholipid is of the structure:

wherein R and R′ are C 6 to C 25 hydrocarbon groups and A is selected from the group consisting of halide, nitrate, sulfate, phosphate, anions of C 1 to C 10 organic acids and mixtures thereof.

18. The method of claim 16 , wherein the phospholipid is selected from the group consisting of a cocadmidopropyl PG-dimonium chloride phosphate salt, a ricinoleamidopropyl PG-dimonium chloride phosphate, a dilinoleamidopropyl PG-dimonium chloride phosphate, sodium cocamidopropyl PG-dimonium chloride phosphate and sodium dilinoleamidopropyl PG-dimonium chloride phosphate, a dimer dilinoleamido-propyl PG-dimonium chloride phosphate; linoleamidopropyl PG-dimonium chloride phosphate dilinoleamidopropyl PG-dimonium chloride phosphate, a 1-propanaminium, 3,3′,3″-[phosphinylidynetris(oxy)]tris[N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-, N,N′,N″-tri-C 6-18 acyl derivative trichlorides, at least one fatty acid amidopropyl propylene glycol dimonium phosphate salt wherein the fatty acid is a C 10 C 25 fatty acid and mixtures thereof.

19. A method of stimulating a subterranean formation penetrated by a well comprising contacting the formation with an acidizing composition comprising, as a first member, an inorganic or organic acid and, as a second member (a) an organophosphorus surfactant selected from the group consisting of amino phosphonates and phosphino carboxylates and the combination of urea or a urea derivative and a bifunctional organic compound comprising (i) at least one quaternary ammonium moiety and at least one —OH group; and further comprising at least one of the following:

(a) retarding spending of the acid by adsorbing the organophosphorus surfactant onto a surface of the formation; or

(b) delaying spending of the inorganic or organic acid by limiting bonding sites for the acid with the organophosphorus surfactant adsorbed on a surface of the formation;

(c) enhancing the creation and penetration of wormholes by retarding or slowing down the spending of the acid wherein the formation is a carbonate formation;

(d) delaying spending of the acid with the second member, wherein the second member comprises the combination of urea or a urea derivative and a bifunctional organic compound comprising (i) at least one quaternary ammonium moiety and at least one —OH group; and

(e) retarding spending of the acid in the formation by disrupting hydrogen bonding of water, limiting the rate of disassociation of the acid and decreasing transfer of an acid proton onto the surface of the formation.