Effect of Capillary Relaxation on Water Entrapment after Hydraulic Fracturing Stimulation

Abstract

Effect of retardation in fluid displacement on transport inside capillary tubes during leak-off and clean-up for hydraulically stimulated reservoirs is investigated by modeling of the relevant phenomena. The effect of wall proximity during the transport in narrow capillaries is formulated. The importance of the critical properties alteration due to confinement is demonstrated by modification of the real gas deviation factor. The relaxation in fluid displacement observed in the fluid transport dynamics is coupled with the bundle of tubes representation of porous media for investigation of the relaxation effects on fluid saturation, capillary pressure, and relative permeability. An analytical formulation of the relaxation time corresponding to water removal during clean-up processes following hydraulic fracture stimulation is presented. The dynamics of advancement of the wetting and non-wetting fluids inside capillary tubes are illustrated by various applications.

Investigation of Water Leakoff Considering the Component Variation and Gas Entrapment in Shale During Hydraulic-Fracturing Stimulation

“…Microscopic features of the shale matrix are welldocumented by well-established characterization techniques such as scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), focused ion beam (FIB)-SEM, and transmission electron microscopy (TEM). During the last several years, various pores in shale were identified (Loucks et al 2009;Curtis et al 2010;Milner et al 2010;Slatt and O'Brien 2011). Schieber (2010) claimed that the matrix-related pores are associated with organic matter, clay minerals (phyllosilicates), and other minerals such as quartz and carbonate (Fig.…”