Constant-Pressure Analysis of Infinite-Conductivity Fractured Gas Wells Influenced by Non-Darcy Flow Effects

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractNon-Darcy flow effects have long been recognized to have serious adverse impact on the performance of high-flow rate gas wells. These effects may mask the presence of fractures around the wellbore of naturally fractured reservoirs and may render the effective fracture conductivity and fracture halflength of hydraulically fractured wells much less than the designed parameters. Proper diagnosis of the post-fracture well test and good estimation of the fracture parameters are crucial for proper MHF treatment assessment and production forecast.Even though the effects of non-Darcy flow have been identified in the field and properly acknowledged in the well testing literature, little has been done to improve the well test analysis results. This paper presents for the first time a semianalytical equation that incorporates the effects of non-Darcy flow in the fracture. The proposed equation describes the flow of real gas under constant bottomhole-pressure condition which has the advantage of reducing the well test duration and minimizing the wellbore storage effects.A detailed investigation of the various parameters influencing the flow behavior of real gas in the fracture nearby the wellbore is also illustrated.

The state-of-the-art in natural gas production

“…Several studies have been done on turbulence effects in hydraulically fractured gas wells (Wang and Economides, 2004;Gil et al, 2001;Lolon et al, 2004;Kakar et al, 2004;Miskimins et al, 2005;Ouyang, 2007;Huang and Ayoub, 2007;Friedel et al, 2007;Nashawi, 2007) and gas condensate wells Indriati et al, 2002;Ravari and Ibrahim, 2005;Ravari et al, 2007;Mahdiyar et al, 2008). Studies (Gil et al, 2001;Ubani and Evans, 1982) showed that significant turbulence flow can exist in a fracture at any time in the life of a vertically fractured gas well.…”