Ultra Lightweight Proppants: Their Use and Application in the Barnett Shale

Abstract

Abstract One of the more active areas for drilling gas wells has been in the Fort Worth Basin in North Texas in a fractured shale formation called the Barnett Shale. Over 2000 wells have been drilled in this non-conventional gas reservoir over the past five years. Initial stimulation treatments in the Barnett Shale began in the early 1980's and consisted of pumping moderate fracture stimulations of approximately 300,000 gals. of fluid and 300,000 lbs. of proppant, typically sand. These treatments quickly evolved to massive hydraulic fracture treatments that used extremely large volumes of conventional crosslinked fracture fluids utilizing over 750,000 gallons of fluid and over 1.0 million pounds of sand. These treatments continued to evolve through early 1997 based on the success in the East Texas area of the slickwater fracturing technique being applied to tight gas sands, in particular the Cotton Valley Sand. Since that time many operators have found success in these types of reservoirs utilizing large volumes of slickwater with low concentrations of proppant. A major concern in utilizing slickwater and fracture injection rate as the only means to transport proppant into the reservoir is the inefficiency of obtaining the most effective propped fracture. The next evolution to improving proppant transport and ultimately more effective fracture length is the use of Ultra Lightweight proppants. This paper will present the application and results of fracture treatments performed in the Barnett Shale using a new ultra lightweight propping agent. The paper will also discuss the applicable Newtonian solids transport theory and it's relation to the density of the proppant and the fluid in which it is being pumped.