Viscosity reduction

A well treatment method, comprising:

• introducing an aqueous treatment fluid comprising a viscosifying polymer into the well, and
• contacting the fluid with a breaker package comprising an organic peroxide and an activator to lower an effective concentration of the peroxide to break the fluid, wherein a weight ratio of the activator:organic peroxide is at least about 1:20, and wherein the organic peroxide comprises a peroxyester.

A well treatment method, comprising:

• introducing an aqueous treatment fluid comprising a viscosifying polymer into the well, and
• contacting the polymer with a peroxyester effective to break the fluid viscosity.

A well treatment method, comprising:

• introducing an aqueous treatment fluid comprising a viscosifying polymer into the well, and
• contacting the polymer with a breaker package comprising an organic peroxide and a breaker delay agent, wherein the delay agent has the formula RR1NR2 wherein R, R1, and R2 are independently selected from hydrogen, alkyl, hydroxyalkyl, and combinations thereof.

A well treatment method, comprising:

• introducing an aqueous treatment fluid comprising a viscosifying polymer into the well, and
• contacting the fluid with a breaker package comprising an organic peroxide and an activator to lower an effective concentration of the peroxide to break the fluid, wherein the weight ratio of activator:peroxide is from about 1:1 to about 20:1.

A well treatment method, comprising:

• introducing an aqueous treatment fluid comprising a viscosifying polymer and a stabilizer into the well, and
• contacting the fluid with a breaker package comprising an organic peroxide and an activator to lower an effective concentration of the peroxide to break the fluid, wherein a weight ratio of the activator:organic peroxide is at least about 1:20.

A well treatment method, comprising:

• introducing an aqueous treatment fluid comprising a viscosifying polymer into the well, and
• contacting the fluid with a breaker package comprising an organic peroxide and an activator to lower an effective concentration of the peroxide to break the fluid, wherein a weight ratio of the activator:organic peroxide is at least about 1:20,
• wherein the polymer is broken in a window from about 5 minutes up to less than about 150 minutes following the contact.