Simulation of Heterogeneous Sandstone Experiments Characterized With CT Scanning

Abstract

Coreflood experiments in naturally heterogeneous sandstone outcrop cores were conducted 1ijld simulated. Displacements included waterfloods and polymer floods containing tracers for oil or water during single-phase and two-phase flows. Displacements of viscous polymer solution were unstable. The cores were characterized by air permeability measureIllentson each square centimeter of each face and by computerized tomography (CT) scans of core cross sections spaced 1 cm apart along the core length. Characterization data were used for fine-grid simulations. The agreement between the experiments and simulations is good. Sipmlations with coarser-grid physical descriptions then were made by use of effective properties..

Residual Oil Saturation from Polymer Floods: Laboratory Measurements and Theoretical Interpretation

“…A two-dimensional numerical grid was used for the coreflood simulation. Ganapathy et al (1991) showed that threedimensional grids gave almost the same result as the two-dimensional grids due to the small permeability variations and the relatively thinner dimension in y direction (orthogonal to face B and D, Figure 3). The permeability field used for the simulation is based on the arithmetic average of the corresponding points of air permeability of face B and D. Figure 4 is a contour plot of the permeability field for AN-4.…”

“…No additional oil was produced. The experimental results and comparison with UTCHEM simulations for one of these tertiary polymer floods can be found in Ganapathy et al (1991).…”

“…Thus, very little is known about the effect of small-scale heterogeneity, frequently observed in laboratory cores, on residual oil saturation. This paper reports a systematic investigation of the residual oil saturations from waterfloods and secondary and tertiary polymer floods, with detailed accounting of small-scale heterogeneity in cores, carried out at University of Texas at Austin (Wreath 1989;Ganapathy et al 1991;Wang 1995;Lu 1994).…”

Accurate determination of characteristic relative permeability curves

“…Previously however, an accurate, repeatable and non-destructive technique was not readily available. A minipermeameter has been used in some studies to directly characterize sub-core scale heterogeneity, and numerical simulations of these models typically match experimental results very well (Giordano et al 1985;Kortekaas 1985;HartkampBakker 1991;Corbett et al 1992;Ganapathy et al 1993;Honarpour et al 1995;Huang et al 1996;Hamon and Roy 2000). Although this approach has worked well in research applications, precision and accuracy are limited, and measurements are constrained to the near surface.…”

Selecting X-Ray Energy Levels for Three-Phase Saturation Measurements

“…[1][2][3][4][5][6] Today, many of the worlds reservoirs are declining, and the need for accurately assessing a reservoir is therefore even more important than before. 7 Despite this, for laboratory work reported in the petroleum literature, measurement uncertainties are often neglected.…”