Types of Fracturing Fluids and Additives

Service companies have developed a number of different oil- and water-based fluids and treatments to more efficiently induce and maintain permeable and productive fractures. The composition of these fluids varies significantly, from simple water and sand to complex polymeric substances with a multitude of additives. Each type of fracturing fluid has unique characteristics, and each possesses its own positive and negative performance traits. For ideal performance, fracturing fluids should possess the following four qualities (Powell et al., 1999)  

Water alone is not always adequate for fracturing certain formations because its low viscosity limits its ability to transport proppant. In response to this problem, the industry developed linear and cross-linked fluids, which are higher viscosity fracturing fluids. Water gellants or thickeners are used to create these gelled fluids. Gellant selection is based on formation characteristics such as pressure, temperature, permeability, porosity, and zone thickness. These gelled fluids are described in more detail below. 

Jeff Gelski, of Good Business News, has stated that, The oil industry s increased use of guar gum has driven up its price, leaving food and beverage processors struggling to find supply of the ingredient used in such applications as ice cream and tortillas (Rohrlich, 2011). 

To formulate a viscous fracturing gel, guar powder or concentrate is dissolved in a carrier fluid such as water or diesel fuel. Increased viscosity improves the ability of the fracturing fluid to transport proppant and decreases the need for more turbulent flow. Concentrations of guar gelling agents within fracturing fluids have decreased over the past several years, as it was determined that reduced concentrations provide better and more complete fractures (Powell et al., 1999) this decreased use may make the food industry happier. 

The final concentration of cross-linkers is typically 1 to 2 gal of crosslinker per 1000 gal of gel (USEPA, 2004). 

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