This paper discusses the effect of non-Darcy flow on transient pressure analysis of hydraulically fractured wells. Common oversight of the results that exist in the literature is noted. The authors emphasize that non-Darcy flow in the fracture affects the estimates of fracture conductivity and fracture half-length. The limitations of buildup analysis under non-Darcy flow conditions in the fracture are discussed. Synthetic and field examples are presented to demonstrate the errors caused by neglecting the non-Darcy flow in the fracture. The paper shows that, for the examples considered here, traditional pressure transient analysis neglecting non-Darcy flow may lead to errors up to 78% and 54% in the estimates of the fracture conductivity and fracture half-length, respectively. The examples also show that even the fractures with moderate production rates may be subject to the effects of non-Darcy flow.
Author(s): S. Umnuayponwiwat, E. Ozkan, Colorado School of Mines; C.M. Pearson, M. Vincent, Carbo Ceramics Inc.
Paper Number: SPE 63176