Abstract: A hydraulic fracturing process in which substantial quantities of both nitrogen and carbon dioxide are incorporated into the fracturing fluid. Nitrogen and carbon dioxide are separately incorporated into an aqueous based fracturing fluid in amounts to provide a volume ratio of nitrogen to carbon dioxide at wellhead conditions within the range of about 0.2-1.0. The volume ratio of the total of carbon dioxide and nitrogen to the aqueous phase of the aqueous fracturing fluid at wellhead conditions within the range of about 1-4. The aqueous fracturing fluid containing the nitrogen and carbon dioxide is injected in the well under a pressure sufficient to implement hydraulic fracturing of the subterranean formation undergoing treatment. A thickening agent may be incorporated into water to provide a viscous aqueous based fracturing fluid to which the carbon dioxide and nitrogen are added. The carbon dioxide is incorporated in liquid phase and the nitrogen in gaseous phase.

Abstract: A method of fracturing a subterranean formation involving the use of crosslinked gels to form a fracture and deposit particulate proppant therein followed by the introduction of dilute aqueous solutions of chlorine dioxide in the propped fracture to degrade the gel.

Abstract: A method for staging a fracturing treatment in a horizontal wellbore where solidified gel is used as a diverting medium. A desired section of the horizontal wellbore farthest removed from the angle of deviation from vertical of the wellbore is perforated. Via perforations contained in the horizontal section, the desired interval is fractured hydraulically. The gel is displaced with a "wiper plug" and the gel confined to the fractured interval and wellbore area adjacent the fractured interval. Here the gel forms a solid gel in the interval and a gel plug in the wellbore. Afterwards, another section of the horizontal well is perforated. Thereafter, a second desired interval is fractured. After completion of the fracturing process, the gel plug breaks and the "wiper plug" is pumped to the farthest end of the horizontal wellbore.

Abstract: A composition and method for stimulating the production of hydrocarbons from wells partially plugged by paraffins or mineral scale, the composition comprising hydrochloric acid, naphtha and an aqueous solution of hydrogen peroxide. According to the method of the invention, the reactants are serially introduced into the well bore and permitted to react to substantial completion, followed by flushing the wellbore with hot water.