Compositions and methods for treating oil and gas wells

1. A composition for use in down-hole operations in an oil and gas well to effect wellbore cleaning filter cake removal and/or acidizing comprising:

A. an ether having the general formula:

R—O—R 1   I

wherein R and R 1 are each alkyl groups which, independent of each other, can be linear or branched containing from about 1 to about 29 carbon atoms; said ether being present in an amount of 40 to 90 wt %;

B. at least one additional component selected from the group consisting of:

(i) an ester of the formula:

or

wherein R 2 -R 5 are linear or branched alkyl groups having from 1 to 30 carbon atoms and n is from 0 to 20;

(ii) an alkoxylated alcohol having the general formula:

CH 3 (C x H 2x )—O—(C n H 2n O) y —(C 2 H 4 O) z —H  IV

wherein x is from 3 to 30, n is from 2 to 4, y is from 0 to 6 and z is from 3 to 20; and

(iii) mixtures of (i) and (ii):

(iv) an acid; and

(v) mixtures of (i), (ii) and (iv); and

C. a co-solvent comprising a liquid hydrocarbon containing from about 6 to about 30 carbon atoms, and from about 20 to about 90 wt % naphthenics, isoparaffins or mixtures thereof.

2. The composition of claim 1 wherein the co-solvent comprises from about 10 to about 35 wt % isoparaffins and, from about 30 to about 73 wt % naphthenics, all of which contain about 8 to about 30 carbon atoms.

3. The composition of claim 1 wherein the combined amount of ester and alkoxylated alcohol being present in an amount of from about 0.01 to about 5 wt %.

4. The composition of claim 1 wherein said co-solvent is present in an amount of from about 10 to about 90 wt %.

5. The composition of claim 1 wherein said composition contains up to about 95 wt % ether.

6. The composition of claim 1 wherein each R and R 1 contain from 5 to 7 carbon atoms.

7. A method of treating a wellbore comprising:

I. providing a composition comprising one of;

Formulation A comprised of an ether having the general formula

R—O—R 1   I

wherein R and R 1 are each alkyl groups which, independent of each other, can be linear or branched containing from about 1 to about 29 carbon atoms, said ether being present in an amount of 40 to 90 wt %; and

Formulation B comprised of Formulation A and at least one additional component selected from the group consisting of:

(i) an ester of the formula:

or

wherein R 2 -R 5 are linear or branched alkyl groups having from 1 to 30 carbon atoms and n is from 0 to 20;

(ii) an alkoxylated alcohol having the general formula:

CH 3 (C x H 2x )—O—(C n H 2n O) y —(C 2 H 4 O) z —H  IV

wherein x is from 3 to 30, n is from 2 to 4, y is from 0 to 6 and z is from 3 to 20; and

(iii) mixture of (i) and (ii)

Formulation C comprised of Formulation A and a hydrocarbon co-solvent;

Formulation D comprised of Formulation B and a hydrocarbon co-solvent;

Formulation E comprised of Formulation A and an acid;

Formulation F comprised of Formulation B and an acid;

Formulation G comprised of Formulation C and an acid;

Formulation H comprised of Formulation B and a hydrocarbon co-solvent;

Formulation I comprised of Formulation F and a hydrocarbon co-solvent;

II. introducing at least one of Formulations A-I into a wellbore; and

III. performing an operation comprising one of:

wellbore cleaning;

(ii) filter cake removal;

(iii) acidizing.

8. The method of claim 7 wherein said co-solvent comprises a liquid hydrocarbon containing from 6 to about 30 carbon atoms.

9. The composition of claim 8 wherein said co-solvent contains from about 20 to about 90 wt % napthenics, isoparaffins or mixtures thereof.

10. The composition of claim 8 when the co-solvent comprises from about 10 to about 35 wt % isoparaffins and from about 30 to about 73 wt % napthenics, all of which contain about 8 to 30 carbon atoms.

11. The method of claim 7 wherein the combined amount of ester and alkoxylated alcohol being present in an amount of from about 0.01 to about 5 wt %.

12. The method of claim 7 wherein said acid is selected from the group consisting of a hydrochloric acid, hydrofluoric acid, formic acid and acetic acid and mixtures thereof.

13. The method of claim 7 wherein each of R and R 1 contain from 5 to 7 carbon atoms.