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Polymer Flood Design for Displacement of Heavy Oil Analysed by 2D-imaging
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, IOR 2013 - 17th European Symposium on Improved Oil Recovery, Apr 2013, cp-342-00034
- ISBN: 978-90-73834-45-3
Abstract
Waterflooding and polymer assisted waterflood in heavy oil reservoirs has recently gathered great attention. Enhanced water injection schemes represent an alternative in cases where thermal methods are either impractical or uneconomic. This study describes the frontal displacement and analyses the oil mobilization by use of 2D X-ray imaging. This study has investigated viscous instabilities, mechanisms for finger growth and water channeling at adverse mobility ratio during waterflood. Experiments have been made on Bentheimer sandstone slabs (30cm x 30cm x 2,5 cm) studying waterflooding and tertiary polymer injection in extra heavy oils (2000cp). The sandstone represents a relatively homogeneous and high permeability porous medium. The experiments utilize gamma and X-ray source for porosity and saturation measurements, and an X-ray imaging system to visualize displacements and thereby quantify the underlying flow mechanisms and oil recovery. The rock material was aged with crude oil to shift wettability and dampen the capillarity. The development of viscous fingers was detailed recorded by 2D X-ray imaging. This paper focuses on polymer slug design. The polymer slug will be influenced by polymer adsorption, inaccessible pore volume, dispersive mixing, and also chase water fingering into the polymer slug. The polymer slug mixing is studied using 2-D imaging by tagging each injected phase. Special focus has been on chase water mixing into the polymer slug. The oil recovery the waterflood was 39% OOIP, but more important a quick increase in oil cut was obtained by polymer injection. The oil recovery after polymer flooding reached final recoveries of more than 70% of OOIP.