This paper presents an experimental and numerical study to investigate the effects of viscous, capillary, and gravity forces on compositional two-phase displacements in layered porous media. We use glass bead packs of different sizes to construct a quasi 2-D porous medium of three layers with different uniform permeabilities. We adapt an analogue ternary fluid system (isooctane, brine, and isopropanol) which allows us to control interfacial tension between the phases at ambient laboratory conditions. Flooding experiments use immiscible and near miscible fluids using the analogue ternary system. We report recovery of phases, compositional analysis, and snapshots of saturation distributions during each experiment. We show that the high flow capacity domain as defined by the high permeability layer and its thickness always dominates displacements. However, its degree depends on the location of the high-permeability layer and the balance between the driving forces. Compositional analysis of effluent indicates that the compositional path is slightly different for the low and high injection rates in the high interfacial tension (IFT) immiscible displacements whereas it is sensitive to the location of high-permeability layer in the low-IFT near-miscible floods. The Peclet numbers indicate the presence of dispersion in the experiments and crossflow affects the recoveries. We also perform black oil simulations to validate the experimental observations. In general, we obtain consistent results between the experimentally measured and numerically obtained data. However, in order to account for the displacement physics and accurately predict the recovery performance, one may need to employ a fully compositional simulation model that captures the tie-line slopes correctly along with the transport properties and gravity. The compositional simulations can provide additional details in terms of component recoveries.

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This paper presents an experimental and numerical simulation study to investigate the effects of driving forces on non-equilibrium compositional displacements in naturally fractured reservoirs. A quasi 2-D glass bead pack is used to represent a cross section of small sector in a fractured reservoir. The matrix and fracture of the reservoir are represented by glass beads and a grooved glass strip, respectively. Conductive, isolated and inclined fractures are studied. A complex fracture network is also investigated by building two fractures crossing each other. An analogue ternary fluid system (isooctane, brine and isopropanol) is used to control the interfacial tension (IFT) between the phases at ambient conditions. Immiscible, near-miscible and miscible floods are conducted. Recovery of phases, compositional analysis and snapshots of saturation distributions are reported. Numerical simulations are used to interpret experimental observations. In all fractured models, capillary forces are found to be the main controlling factor in immiscible displacements. However, in miscible displacements, the balance between gravity and viscous forces leads to higher swept area and may be higher recovery in some of the cases. The position of a fracture affects the displacement performance significantly. Compositional analysis of the effluent indicates that the compositional path changes between tie-lines of initial and injection liquids based on saturation profile development. Force-balance scaling criteria (i.e. capillary, gravity and Bond numbers) were used to diagnose flow regimes during displacements. Then experimental results have been interpreted by black oil simulator. Experimental observations of immiscible displacements were sufficiently predicted. However, in order to accurately predict the results of miscible displacements, a fully compositional simulator is recommended.

In this paper, we present a laboratory study that investigates the behaviour of compositional displacements in multi-layered porous media. A quasi two-dimensional glass bead pack was used in the experiments. The porous medium had three uniform layers with each having a different permeability because of the different glass beads. An analog two-phase three-component liquid ternary system was used in the experiments at ambient conditions to mimic a condensing gas drainage displacement under reservoir conditions. We report a total of nine experiments which include three horizontal and six vertical cross-section displacements with different injection and initial fluids. The fluids chosen represent immiscible, near miscible and first-contact miscible systems. The effluents were collected for each experiment and their compositions were measured using gas chromatography. Several snapshots of the fluid distributions in the porous medium were taken during each experiment. The experimental results show that the horizontal displacements gave a better sweep efficiency. Most of the displacements took place in the high-permeability layer with the low-permeability layer not even touched, gravity effects were favourable in the vertical cross-section displacements where the high-permeability layer was at the bottom, and the gravity reduced the swept area in the flood with the flipped vertical cross-section model. The measured compositional data indicates differences in the compositional paths for different displacements.

This paper investigates the effects of gravity drainage on non-equilibrium compositional displacements in naturally fractured reservoirs (NFRs) by presenting an experimental and numerical simulation study. A quasi 2-D glass bead pack is used to represent a NFR. The matrix and fracture are represented by glass beads and a grooved glass strip, respectively. Conductive fractures are studied. An analogue ternary fluid system (isooctane, brine and isopropanol) is used to control the interfacial tension (IFT) between the phases at ambient conditions. Immiscible, near-miscible and miscible floods are studied. Recovery of phases, compositional analysis and snapshots of saturation distributions are reported. Numerical simulations are used to interpret experimental observations.In immiscible displacements, capillary forces are found to be the main controlling factors for the vertical cross-section reservoir model while a balance between capillary and gravity forces governs gravity drainage displacements. In miscible displacements, the balance between gravity and viscous forces controls sweep efficiency and recovery factor for both reservoir models. Near-mmiscible miscible floods give higher recovery than first-contact miscible floods under gavity drainage. This opposes to the observation made for the horizontal floods. This is in line with the finding reported in the literature using numerical simulations.Force-balance scaling criteria (i.e. capillary, gravity and Bond numbers) diagnose flow regimes during displacements satisfactorily. Black oil simulations sufficiently predict experimental observations of all displacements examined provided that history-matched capillary pressure and relative permeability are used. Compositional analysis of the effluent indicates that the compositional path changes between tie-lines of initial and injection liquids based on saturation profile development.