Abstract: The invention provides a method for treating a subterranean formation penetrated by a wellbore, the method comprising the steps of formulating a treatment fluid and introducing the treatment fluid through the wellbore. The treatment fluid comprises water; diutan; and a sufficient amount of salt to increase the density of the treatment fluid to at least 8.5 lb/gal, wherein at least 50% by weight of the salt is selected from the group consisting of: bromide salts, non-bromide salts having a higher salting-in effect than bromide according to the Hofmeister series as measured by the salt's effect on the cloud point of poly(ethylene oxide) that has a molecular weight of 4×106, and any combination in any proportion thereof. The invention also provides a treatment fluid for use in a subterranean formation penetrated by a wellbore, the treatment fluid comprising: water; diutan; and a sufficient amount of salt to increase the density of the treatment fluid to at least 8.

Abstract: The invention provides a method for treating a subterranean formation penetrated by a wellbore, the method comprising the steps of formulating a treatment fluid and introducing the treatment fluid through the wellbore. The treatment fluid comprises water; diutan; and a sufficient amount of salt to increase the density of the treatment fluid to at least 8.5 lb/gal, wherein at least 50% by weight of the salt is selected from the group consisting of: bromide salts, non-bromide salts having a higher salting-in effect than bromide according to the Hofmeister series as measured by the salt's effect on the cloud point of poly(ethylene oxide) that has a molecular weight of 4×106, and any combination in any proportion thereof. The invention also provides a treatment fluid for use in a subterranean formation penetrated by a wellbore, the treatment fluid comprising: water; diutan; and a sufficient amount of salt to increase the density of the treatment fluid to at least 8.

Abstract: Methods are provided that include a method comprising providing a viscosified treatment fluid comprising a base fluid and a gelling agent that comprises a clarified xanthan; and placing the viscosified treatment fluid into at least a portion of a subterranean formation. In some embodiments, the method comprises placing the viscosified treatment fluid into at least a portion of a subterranean formation at a pressure sufficient to create or enhance at least one fracture in the subterranean formation. In some embodiments, the viscosified treatment fluid may also comprise a plurality of particulates. In some embodiments, the viscosified treatment fluids may be placed into at least a portion of a pipeline. Additional methods are also provided.

Abstract: The invention provides a method for treating a subterranean formation penetrated by a wellbore, the method comprising the steps of formulating a treatment fluid and introducing the treatment fluid through the wellbore. The treatment fluid comprises water; diutan; and a sufficient amount of salt to increase the density of the treatment fluid to at least 8.5 lb/gal, wherein at least 50% by weight of the salt is selected from the group consisting of: bromide salts, non-bromide salts having a higher salting-in effect than bromide according to the Hofmeister series as measured by the salt's effect on the cloud point of poly(ethylene oxide) that has a molecular weight of 4×106, and any combination in any proportion thereof. The invention also provides a treatment fluid for use in a subterranean formation penetrated by a wellbore, the treatment fluid comprising: water; diutan; and a sufficient amount of salt to increase the density of the treatment fluid to at least 8.