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U.S. Department of Energy
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Fracturing fluid leakoff under dynamic conditions Part II: Effect of shear rate, permeability, and pressure

Conference ·
OSTI ID:457349
This paper discusses the results of an industry consortium established to understand and allow modeling of the fluid leakoff process in hydraulic fracturing applications. Over 1,000 laboratory experiments structured to study the effects of shear rate, permeability, differential pressure, temperature, gel concentration, fluid-loss additives, and fluid type have been conducted. Fluid-loss data was measured with a state-of-the-art experimental setup that included fluid preconditioning loops for high shear and low shear regimes and a novel cell design that minimized flow irregularities. Part 2 presents the results of experiments involving linear hydroxypropyl guar (HPG) gel, HPG/borate systems, and HPG/titanate systems at shear rates between 0 and 200 sec{sup -1}, pressures between 500 to 10,000 psi, a temperature of 180{degrees}F, and core permeabilities between 0.1 md and 1000 md. This study found that fluid loss under dynamic conditions can be significantly higher than under static conditions. Significant differences in fluid-loss behavior were observed between linear gels, transition-metal crosslinked gels, and borate-crosslinked systems. The behavior of linear gels was sensitive to permeability and pressure, but insensitive to shear rate. The behavior of crosslinked gels was more sensitive to shear rate, but less sensitive to permeability and pressure. The fluid loss of all fluids tested could be modeled though the mechanisms of non-Newtonian viscous invasion, classical filter-cake deposition, and filter-cake resuspension. This paper presents guidelines for fluid-loss prediction for these systems with appropriate fluid-loss mechanisms.
OSTI ID:
457349
Report Number(s):
CONF-961003--
Country of Publication:
United States
Language:
English