Methods of biosynthesizing bacterial extracellular galactomannan polysaccharides for use in subterranean formation operations such as drilling operations, fracturing operations, or gravel packing operations including providing a feedstock comprising mannose and galactose; providing bacteria effective at fermenting mannose and galactose; introducing the bacteria to the feedstock; and fermenting the bacteria so as to produce an extracellular galactomannan polysaccharide.

A composition or compositions useful as a well treatment fluid is disclosed containing high molecular weight guar and low molecular weight water soluble polymer having a lower molecular weight than the high molecular weight guar. The composition can also contain water and a crosslinking agent, and the low molecular weight water soluble polymer can include a low molecular weight guar. A method of treating a subterranean formation is also disclosed including placing the composition(s) in the subterranean formation.

Polyglycolic acid resin short fibers for a well treatment fluid, the fibers having the following characteristics of (a) to (e): (a) an outside diameter of 5 to 300 m; (b) a fiber length of 1 to 30 mm; (c) fineness of 0.1 to 25 D; (d) strength of 1 to 20 gf/D; and (e) a ratio of an area of the polyglycolic acid resin with respect to an area of a circle circumscribing a cross section of the fibers being from 10 to 95%; and a well treatment fluid containing the polyglycolic acid resin short fibers for a well treatment fluid.