LIQUEFIED INDUSTRIAL GAS BASED SOLUTION IN HYDRAULIC FRACTURING

摘要

Hydraulic fracturing is commonly performed by injecting a liquid, gas or two-phasefluid down a well bore at sufficient pressure and flow rate to fracture thesubterranean formation. The fluid injected into the rock is typically a slurryof water,proppants, and chemical additives. At the end of the fracturing treatment, thewell iscommonly flushed with water, and the injected fluid is recovered and treatedto somedegree. Although the concentrations of chemical additives are very low, therecovered fluid may be harmful due in part to hydrocarbon contamination.The present invention presents a hydraulic fracturing treatment that issubstantiallyfree of water. Specifically, the present invention is a cryogenic subterraneanfracturing fluid, comprising a liquefied industrial gas and a first additive.Theliquefied industrial gas may be liquefied carbon dioxide, liquefied nitrogen,or a blendof the two. The liquefied industrial gas mixture should be substantially freeof water.In this context, substantially free of water means less than 10% water byvolume, orpreferably less than 5% water by volume. The first additive may be a biocide.Inaddition to the first additive, a proppant may be added to the fracturingfluid. Inaddition to the biocide and/or proppant, additional additives may be added totheliquefied industrial gas as required. Non-limiting examples of such additivesincludeozone, a friction reducer, an acid, a gelling agent, a breaker, a scaleinhibitor, a claystabilizer, a corrosion inhibitor, an iron controller, an oxygen scavenger, asurfactant,a cross-linker, a non-emulsifier, a pH adjusting agent, or any combinationthereof.