The Areal Sweep Efficien cy of the First Contact Miscible WAG Displacement: An Experimental Approach

摘要

Miscible WAG injection has been implemented in a number ofrnoil fields around the world and there are a number ofrnnumerical studies investigating the effect of rate, gravity, slugrnsize and heterogeneity on WAG performance. However therernare very few laboratory studies of WAG sweep efficiencyrnreported in the literature.rnIn this paper we report the results from a series of wellcharacterizedrnWAG displacements through glass bead-packs.rnThe aim of these experiments was:rn1. to investigate the impact of first contact misciblernWAG injection on sweep efficiencyrn2. to clarify the physical processes duringrndisplacements.rn3. to provide benchmark data-sets that could be used inrnperforming reservoir simulations.rnThe use of bead-packs rather than cores enabled us tornobserve visually, the fluid interactions during each WAGrnexperiment. A series of secondary, miscible WAGrndisplacements were conducted at WAG ratios of 1:1, 1:2 andrn2:1. These were performed at a constant flow rates torneliminate the influence of capillary number on sweeprnefficiency. Results indicate that sweep efficiency is a functionrnof the WAG ratio. Empirical equations of area sweep asrnfunction of mobility ratio for various WAG ratio’s arernobtained. Results of this work will provide additionalrninformation that will be very valuable in performing numericalrnand analytical miscible flooding models.