US Patent 7645725 Subterranean treatment fluids with improved fluid loss control

Fluids useful as subterranean treatment fluids, and more particularly, polymeric fluid loss additives, subterranean treatment fluids with improved fluid loss control, and their associated methods of use, are provided. In one embodiment, the methods comprise: providing a treatment fluid that comprises a base fluid, and a polymeric fluid loss control additive that comprises at least a first plurality of polymer molecules having a first average molecular weight, and a second plurality of polymer molecules having a second average molecular weight, wherein the first average molecular weight is different from the second average molecular weight; and introducing the treatment fluid into a subterranean formation.