A variety of methods, compositions, and systems are disclosed, including, a method comprising: introducing a treatment fluid into a wellbore penetrating a subterranean formation wherein the treatment fluid comprises: a base fluid; and multi-grade diverting particulates, wherein the multi-grade diverting particulates comprise a degradable polymer, wherein the degradable polymer comprises a first portion of the degradable polymer and a second portion of the degradable polymer of different grades, wherein the multi-grade diverting particulate at least partially plugs a zone in the subterranean formation; and diverting at least a portion of the treatment fluid and/or a subsequently introduced fluid away from the zone.

The present invention relates to multi-arm star macromolecules which are used as thickening agents or rheology modifiers, including use in hydraulic fracturing fluid compositions. In one aspect of the invention, a star macromolecule is capable of thickening via a dual mechanism comprising (1) self-assembly of the hydrophobic polymerized segments of the star macromolecules via hydrophobic interactions or associations, and (2) association, reaction, or combination of the hydroxyl-containing polymerized segments of one or more of the star macromolecules.

A gel composition for use in treating subterranean formations is provided. The gel composition is a non-aqueous based oil gel system that can include a hydrocarbon liquid capable of gelation, a phosphate ester, and a cross-linking agent. The gel composition can include the oil gel which results from adding a phosphate ester, a crosslinking agent and a delay additive to the hydrocarbon liquid.

A gel composition for use in treating subterranean formations is provided. The gel composition is a non-aqueous based oil gel system that can include a hydrocarbon liquid capable of gelation, a phosphate ester, and a cross-linking agent. The gel composition can include the oil gel which results from adding a phosphate ester, a crosslinking agent and a delay additive to the hydrocarbon liquid.

A hydrocarbon-based or ester-based drilling fluid or mud is described wherein the drilling fluid contains cesium phosphate. The hydrocarbon-based or ester-based drilling fluid or mud can have, for example, an external phase that contains hydrocarbon fluid and an internal phase that contains cesium phosphate. The hydrocarbon-based drilling fluid or mud can further contain at least one emulsifier or surfactant, and optionally other ingredients. The present invention can permit hydrocarbon-based drilling fluids to be essentially solids-free and may be used without corrosion and/or formation damage problems, for example, due to the use of the cesium phosphate in an internal phase of the hydrocarbon-based or ester-based drilling fluid. The present invention also relates to hydrocarbon-based or ester-based fluids for completion, workover, suspension and packer operations which contain cesium phosphate.

A hydrocarbon-based or ester-based drilling fluid or mud is described wherein the drilling fluid contains cesium phosphate. The hydrocarbon-based or ester-based drilling fluid or mud can have, for example, an external phase that contains hydrocarbon fluid and an internal phase that contains cesium phosphate. The hydrocarbon-based drilling fluid or mud can further contain at least one emulsifier or surfactant, and optionally other ingredients. The present invention can permit hydrocarbon-based drilling fluids to be essentially solids-free and may be used without corrosion and/or formation damage problems, for example, due to the use of the cesium phosphate in an internal phase of the hydrocarbon-based or ester-based drilling fluid. The present invention also relates to hydrocarbon-based or ester-based fluids for completion, workover, suspension and packer operations which contain cesium phosphate.

A silicone polymer is provided, modified with at least one functional group from the class of anthraquinone amide groups; anthraquinone sulfonamide groups; thioxanthone amide groups; or thioxanthone sulfone amide groups. The polymer can be combined with a hydrocarbon solvent or with supercritical carbon dioxide (CO.sub.2), and is very effective for increasing the viscosity of either medium. A process for the recovery of oil from a subterranean, oil-bearing formation is also described, using supercritical carbon dioxide modified with the functionalized silicone polymer. A process for extracting natural gas or oil from a bedrock-shale formation is also described, again using the modified silicone polymer.

A silicone polymer is provided, modified with at least one functional group from the class of anthraquinone amide groups; anthraquinone sulfonamide groups; thioxanthone amide groups; or thioxanthone sulfone amide groups. The polymer can be combined with a hydrocarbon solvent or with supercritical carbon dioxide (CO.sub.2), and is very effective for increasing the viscosity of either medium. A process for the recovery of oil from a subterranean, oil-bearing formation is also described, using supercritical carbon dioxide modified with the functionalized silicone polymer. A process for extracting natural gas or oil from a bedrock-shale formation is also described, again using the modified silicone polymer.

Various embodiments disclosed relate to compositions including functionalized polysaccharide for treatment of subterranean formations and methods and systems including the same. In various embodiments, the present invention provides a method of treating a subterranean formation. The method includes placing in a subterranean formation a composition including a functionalized polysaccharide that includes a hydroxy(C.sub.1-C.sub.5)alkyl functionalization and a polyhydroxy(C.sub.2-C.sub.5)alkyl functionalization.

Various embodiments disclosed relate to compositions including functionalized polysaccharide for treatment of subterranean formations and methods and systems including the same. In various embodiments, the present invention provides a method of treating a subterranean formation. The method includes placing in a subterranean formation a composition including a functionalized polysaccharide that includes a hydroxy(C.sub.1-C.sub.5)alkyl functionalization and a polyhydroxy(C.sub.2-C.sub.5)alkyl functionalization.