The invention discloses a method of effecting fracturing in a subterranean formation utilizing substantially constant density fluids whereby proppant segregation is minimized or eliminated within the formation. Fluid density is adjusted by varying the salt content or addition of a gas or gasifiable liquid or both as proppant is added to the treatment fluid.
Treatment methods including preparation of an aqueous treatment fluid composition composed of a carboxy modified polymer, a crosslinking agent, and a viscosifying quaternary amine salt, and subsequently introducing the composition into a the formation to treat. The treatment method is particularly useful for fracturing a subterranean formation. The polymer and crosslinker may be premixed and injected into a wellbore, then mixed therein with the quaternary amine salt to treat the formation. In another aspect, the polymer, crosslinker, and quaternary amine salt are mixed, injected into a wellbore, and introduced in the formation for treatment.
A well treatment fluid composition that comprises a carrier fluid and an amphoteric surfactant, and optionally a viscosifying agent and proppant, is well suited for use in fracturing coal beds to stimulate methane production. The composition preferably is a foam that comprises a gas such as nitrogen or air. Preferably, the surfactant has the formula wherein R is a saturated or unsaturated alkyl group having from 6-20 carbon atoms, n is from 2-6, and X is hydrogen or a salt forming cation.
A drilling fluid additive for controlling solids comprising a carrageenan material, such as iota or kappa carrageenan. The drilling fluid additive may be used with other additives, such as a polyacrylate dispersant. Among other things, the drilling fluid additive may be used to drill deviated or horizontal wells, or wells having large diameter boreholes.
Storable cement slurries utilize a carrageenan suspending agent to provide stable slurries under conditions of high pH and calcium ion content. These cement slurries may be utilized for, among other things, cementing applications involving oil and gas wells.
Polymers are derivatized and then may be introduced into a wellbore, such as in a hydraulic fracturing treatment. A polymer may be a guar powder that is mixed with a organic solvent and derivatized using a derivatizing agent, such as sodium chloroacetate. The polymer is typically derivatized in bulk prior to introduction into the wellbore. The derivatized polymer may be hydrated and/or crosslinked prior to introduction into the wellbore.
