Analytical and numerical investigation of multicomponent multiphase WAG displacements

Abstract

In this paper the ability of analytical solutions for four-component three-phase flow to predict displacement efficiency in water alternating gas (WAG) injection processes is studied. First analytical solutions for Riemann problems with injection compositions that are the average water and gas mixture for various WAG injection schemes are presented. These solutions are compared to numerical calculations with variable slug sizes and used to explore the effect of slug size, injecting water vs gas first, and the average injection composition on displacement efficiency in compositional WAG schemes. The example model is partially miscible WAG injection of water and CO 2 into an oil reservoir containing C 10 and CH 4 with and without a mobile aqueous phase present initially. The trailing end of the water and gas profiles are sensitive to whether water or gas is injected first, but the magnitude of the oil bank and the breakthrough time of the injected fluids are accurately predicted by the analytical solutions, even for displacements where large water and gas slugs are injected. Fluctuations in the saturation and composition profiles resulting from the alternating injection sequence in the WAG simulations appear as T. LaForce (B) super-imposed on top of the sequence of rarefaction and shock waves predicted by analytical solutions. As the number of slugs increases, the effect of alternating boundary conditions diminishes and the displacements predicted by numerical calculations converge to the analytical solutions.

Investigation on Interfacial Interactions among Crude Oil–Brine–Sandstone Rock–CO2 by Contact Angle Measurements

“…However, the unfavorable gas mobility ratio and the rock heterogeneity contribute to fingering and channeling, which results in poor volumetric sweep efficiency. To improve the mobility ratio between the injected fluid and the oil, water and CO 2 are usually injected in alternating slugs. , It has been shown by different studies that the chemical composition of the aqueous phase has significant effect on the performance of such a process. − At the same time, this may lead to the trapping of a significant volume of oil in the form of ganglia surrounded by thin water films. Consequently, the injected gas may not directly contact the trapped oil .…”

“…To improve the mobility ratio between the injected fluid and the oil, water and CO 2 are usually injected in alternating slugs. 5,6 It has been shown by different studies that the chemical composition of the aqueous phase has significant effect on the performance of such a process. 7−9 At the same time, this may lead to the trapping of a significant volume of oil in the form of ganglia surrounded by thin water films.…”

Analytical Solutions for Multicomponent, Two-Phase Flow in Porous Media with Double Contact Discontinuities

“…Only recently, have researchers considered multiphase injection compositions (Seto 2007;LaForce and Jessen 2007). Although two-phase injection compositions have not been thoroughly investigated in gas displacements, they have been explored for immiscible threephase flow (Falls and Schulte 1992;Guzman and Fayers 1997;Marchesin and Plohr 2001;Juanes and Patzek 2004;LaForce et al 2008).…”

Monte Carlo Simulation of the CO2 Flooding Efficiency at a Core Scale for Different Oil Compositions

“…There are several distinct methods of CO 2 flooding. The huff and puff process [19,20], the CO 2 foam injection [21,22], and the water-alternating-gas (WAG) injection [16,[23][24][25] method are among the most well known. The latter approach is based on alternating periods of continuous water and gas injection through one group of wells and the oil extraction through another group of wells.…”