Linear Waterflood Behavior and End Effects in Water-Wet Porous Media

Abstract

Introduction Theory indicates that linear waterfloods should exhibit scaling and stabilization properties in both oil-wet and water-wet porous media. Experimental verification of these properties in oil-wet media was obtained some time ago, and more recently, Perkins employing a high permeability unconsolidated sand and a low oil-to-water viscosity ratio, has obtained flooding data in a water-wet medium which follow the pattern of scaling and stabilization. Also, Root and Calhoun have found similar trends in the displacement of gas by liquids from unconsolidated sands. In general, however, the experimental evidence appears still somewhat conflicting since scaling and stabilization of water floods in water-wet media has not been observed in most of the studies to date. The purpose of this paper is to provide a more comprehensive picture of waterflood behavior in water wet media and to corroborate the validity of the scaling and stabilization concepts. The need for differentiating between the intrinsic nature of water-oil displacements inside a porous medium and perturbating secondary end effects is discussed, pertinent experimental procedures are outlined and the results of flooding tests conducted at low and at high oil-to-water viscosity ratios on consolidated, water-wet Alundum cores are analyzed.

Scaling of oil recovery by spontaneous imbibition for wide variation in aqueous phase viscosity with glycerol as the viscosifying agent

“…In this study, glycerol (CH 2-OHCHOHCH 2 OH), supplied at 99.5% purity by EMD Chemicals, Inc., was utilized to viscosify the wetting phase. In previous studies, glycerol was used to viscosify the aqueous phase for the purpose of adjusting the oil/ aqueous phase viscosity ratio (Leverett, 1941;Rapoport and Leas, 1953;Kyte and Rapoport, 1958). None of the reports give detailed information on the physical properties of aqueous glycerol solutions.…”

Comparison of Two-Phase Darcy’s Law with a Thermodynamically Consistent Approach

“…But this equation now needs to hold both for the general case with ∇ S α = 0 (which is the case in unsteady-state flow, for instance) and for the special case of ∇ S α = 0 (such conditions occur in steady-state flow far away from boundaries; Tiab and Donaldson 2004;Kyte and Rapoport 1958;Cable et al 2000;Poulsen et al 2000;Kalam et al 2007;Dong and Dullien 1997;Bacri et al 1990). Inserting Eq.…”

Coreflooding Studies to Evaluate the Impact of Salinity and Wettability on Oil Recovery Efficiency

“…If the flow rate is not stabilized during the forced displacement phase, capillary entry and end-effects may become pronounced. The modified Amott-Harvey method used in this work ensured that capillary entry and end-effects were minimized and that stabilized flow was achieved within the core plugs by ensuring that: (1) the overall pressure drop across the core plug during the forced displacement phase was greater than 344.7 kPa (50 psi; Rapoport and Leas 1953) and (2) the Rapoport and Leas number (Rapoport and Leas 1953;Kyte and Rapoport 1958) was maintained at a reasonably high value and ranged between 7.75×10 −8 N (72.06 ft 2 cp/D) and 1.84 × 10 −7 N (171.2 ft 2 cp/D). The implication is that any distortion in data as a result of the changes in capillary pressure with saturation (∂ P c /∂ S) is minimized.…”