Gas well treatment compositions and methods

In a method of fracturing a subterranean formation having a low permeability to increase the production of gas therefrom wherein a foam fracturing fluid containing an aqueous base fracturing fluid, a gas component and a foaming agent component for generating a foam in associated with the base fracturing fluid and gas component is used to fracture the formation and then recovered from the formation, the improvement comprising employing as said foaming agent component a micellar foaming agent whereby the ability of said foam fracturing fluid to be recovered from said formation is enhanced, said micellar foaming agent comprising:

• (a) about 25% to about 50% by volume of a microemulsion generating component which forms a water external microemulsion when added to the base fracturing fluid and enhances the ability of said foam fracturing fluid to be recovered form said formation, said microemulsion generating component including:
• (i) an alkyl alcohol having in the range of from 4 to 18 carbon atoms;
• (ii) a microemulsifying agent present in an amount sufficient to form and maintain a stable microemulsified dispersion of said alkyl alcohol in the water external phase of said microemulsion;
• (iii) a microemulsion mutual solvent selected from the group consisting of glycol ethers;
• and
• (iv) a microemulsion co-solvent selected from the group consisting of polyethylene glycol, primary alcohols and alkyoxylates of alkyl alcohols, each of said components (i)-(iv) being different compounds or different mixtures of compounds;
• and
• (b) about 50% to about 75% by volume of a foaming agent component for generating a foam in the presence of said base fracturing fluid and said gas component and enhancing the ability of said foam fracturing fluid to be recovered from said formation, said foaming agent component including at least one nonionic surface active agent having a HLB of from 12 to 22, whereby if said foaming agent component consists of a mixture of compounds, it is a different mixture of compounds than said mixture of compounds forming said microemulsion generating component.

A method of displacing blocks of water and other connate fluids interlocked with gas in a subterranean formation to increase the production of gas from the subterranean formation comprising:

• contacting said formation with a water external microemulsion well treatment composition, said well treatment composition including:
• (a) about 90% to about 99.95% by volume of a treatment fluid selected from the group consisting of an aqueous acid solution and an aqueous non-acid solution;
• (b) about 0.0125% to about 5% by volume of a microemulsion generating component said microemulsion generating component including:
• (i) an alkyl alcohol having in the range of from 4 to 18 carbon atoms microemulsified into said treatment fluid;
• (ii) a microemulsifying agent present in an amount sufficient to form and maintain a stable microemulsified dispersion of said alcohol in said treatment fluid;
• (iii) a microemulsion mutual solvent selected from the group consisting of glycol ethers and alkyoxylates of glycol ethers;
• and
• (iv) a microemulsion co-solvent selected from the group consisting of polyethylene glycol, primary alcohols and alkyoxylates of alkyl alcohols, each of said components (i)-(iv) being different compounds or different mixtures of compounds;
• (c) about 0.025% to about 7.5% by volume of a foaming agent component, said foaming agent component including at least one non-ionic surface active agent having a HLB of from 12 to 22, each of said components (a)-(c) being different compounds or different mixtures of compounds;
• and
• recovering said well treatment composition from said formation.