Abstract: Methods for the treatment of subterranean wells involving injecting a first fracturing fluid into a formation, and then injecting at least a second fracturing fluid into the formation in order to create extended conductive channels through a formation are described. The fracturing fluids can be similar in density, viscosity, pH and the other related characteristics. Alternatively, the fracturing fluids can differ in their densities, viscosities, and pH, allowing for variations in the conductive channels formed. Propping agents can also be included in one or both of the injected fluids, further enhancing the conductive channels formed. The described methods aid in minimizing proppant flowback problems typically associated with hydraulic fracturing techniques.

Abstract: Methods and compositions useful for controlling sand production from subterranean formations that utilize relatively lightweight and/or substantially neutrally buoyant particles as particulate sand control material.

Abstract: Cement compositions including mixtures of substantially elastic material and cement that may be formulated exhibit reduced bulk volume shrinkage during curing as compared to conventional cement compositions. In one application, such cement compositions may be used for cementing in substantially closed system, such as the interior of a mold used for producing preformed concrete items.

Abstract: Methods and compositions useful for hydraulic fracturing of subterranean formations that utilize relatively lightweight and/or substantially neutrally buoyant particles as particulate proppant material.

Abstract: A subterranean formation is treated by injecting a blend of fracture proppant material and deformable particulate material into the formation. The deformable particulate material may combine with the fracture proppant material to increase fracture conductivity, reduce fines generation, and/or reduce proppant flowback. The fracture proppant material may be a material such as sand, and the deformable particulate material may be a material such as polystyrene divinylbenzene beads.

Abstract: Solid surfactant suspension compositions are formed by combining solid surfactants, such as alpha-olefin sulfonates, with an organic base fluid, such as diesel. Solid surfactant suspensions may be combined with an aqueous carrier fluid to form surfactant-containing fluids suitable for, among other things, forming foams or for water wetting surfaces. Solid surfactant suspensions may also be combined with additive materials, such as polymer particles, to form a dispersion or emulsion. Polymer-containing solid surfactant suspensions may also be combined with aqueous carrier fluids to form, for example, viscosified, gelled, or foamed fluids. Concentration of solid surfactant materials contained in a solid surfactant suspension may be varied to affect the function the solid surfactant suspension. For example, the solid surfactant material may function as a polymer surface wetting agent, an emulsifier, a dispersant, a viscosifier, and/or a foamer in well completion and remedial and/or workover fluids.

Abstract: A subterranean formation is treated by injecting a blend of fracture proppant material and deformable particulate material into the formation. The deformable particulate material may combine with the fracture proppant material to increase fracture conductivity, reduce fines generation, and/or reduce proppant flowback. The fracture proppant material may be a material such as sand, and the deformable particulate material may be a material such as polystyrene divinylbenzene beads.

Abstract: A method is provided for improving the effectiveness of cleaning up wells in a subterranean formation. The treatment is made more effective by first treating the well with a clean-up fluid that enzymatically degrades residual polymeric viscosifiers followed by removing solids contained in drill-in fluids.

Abstract: A method of fracturing a subterranean formation in a well bore is shown in which a gellable fracturing fluid is first formed by blending together an aqueous fluid, a hydratable polymer, a suitable cross-linking agent for cross-linking the hydratable polymer to form a polymer gel and an enzyme breaker. The cross-linked polymer gel is pumped into the well bore under sufficient pressure to fracture the surrounding formation. The enzyme breaker is allowed to degrade the cross-linked polymer with time to reduce the viscosity of the fluid so that the fluid can be pumped from the formation back to the well surface. The particular enzyme breaker utilized has an activity in the temperature range from about 60.degree.-300.degree. F. and at a pH range from about 2.0 to 11.0 and is effective to attack only specific linkages in the cross-linked polymer gel.

Abstract: High temperature blocking gel is shown for temporary workover operations. The blocking gel is prepared by blending a guar or derivatized guar polymer with an aqueous fluid. The mixing method employed mixes and pumps the guar polymer essentially unhydrated. The resulting lower viscosity minimizes friction pressure during placement.

Abstract: The invention shows a method of degrading damaging material within a subterranean formation of a well bore using an enzyme treatment. Filter cakes and very viscous fluids are such damaging materials. The enzyme treatment degrades polysaccharide-containing filter cakes and damaging fluids which reduces their viscosity. The degraded filter cake and damaging fluid can then be removed from the formation back to the well surface. The particular enzymes utilized are specific to a particular type of polysaccharide and are active at low to moderate temperatures. The enzymes attack only specific linkages in filter cakes and damaging fluids and are active in the pH range of about 2.0 to 10.0.

Abstract: Method of reducing the viscosity of a fracturing fluid containing a polymer by introducing both delayed breaker and nondelayed breaker into the fracturing fluid. Preferably, the relative amounts of delayed and undelayed breaker are determined by first determining the concentration of polymer in the fracture, determining the relationship of breaker concentration for a polymer concentration to proppant pack permeability, picking a desired proppant pack permeability, calculating the amount of breaker necessary to lessen the viscosity of the polymer concentration in the fracture to the desired permeability. This amount of breaker is X. Next, the minimum viscosity of the fracturing fluid which maintains the proppant in suspension in the fracture is determined. The amount of breaker Y which lessens the viscosity of the fracturing fluid no lower than this minimum viscosity is calculated for the bottom hole static temperature and an interval of time.

Abstract: An improved method of mixing a fracturing fluid slurry concentrate comprising a hydrophobic solvent base (e.g., diesel No. 2) and a dispersed hydratable polymer (e.g., hydroxypropyl guar) on a real time basis thus continuously producing a fully hydrated fracturing fluid during the actual fracturing of a subterranean earthen formation. Viscosity rise times of less than 5 minutes are achieved in a continuous operation without the use of large volume storage/hydration tanks, employing primarily conventionally necessary pumps.

Abstract: A fracturing fluid based on quar gum exhibiting good viscosity and stability at temperatures from about 80.degree. C. to at least about 120.degree. C. The fracturing fluid includes a guar gum, a zirconium or hafnium cross-linking agent, and a bicarbonate salt in an aqueous solution at a pH from about 8 to about 10.