Experimental and Numerical Analysis of Polymer Flooding Processes Using Micromodels - From Pore Scale to Continuum Scale - Phase 2

This report covers the results obtained during the second phase of the research project DGMK 746/2 titled “Experimental and Numerical Analysis of Polymer Flooding Processes using Micromodels”. The overall project aims to provide new insights into two-phase displacement processes - in particular polymer EOR processes - using micro visual studies supported by advanced micro models („chips"). The main targets for the second project phase were defined based on several challenges encountered during the first project phase, such as (a) the extension of the laboratory setup to enable flooding experiments at typical reservoir temperature conditions, (b) the design and creation of new advanced micro models based on micro-CT images with specified wetting conditions, (c) the validation of the micro model flooding results by comparison with core flooding as well as (d) a further extension of the polymer rheological database. An improved microfluidics setup with heating capabilities was successfully realized during the project phase, which enabled suitable experimental conditions matching the typical reservoir oil temperatures observed in German oil fields. Also, a core-flooding setup was created at the department which enabled the performance of core-plug experiments at equivalent flooding conditions. For the generation of advanced micro models, micro-CT images were obtained from Bentheimer core plugs, and a workflow was created that aims to convert the 3D flow paths of the real rock to the pseudo-2D flow patterns obtainable in the sandwich micro-models generated in this research project. Instead of a quarter of a 5-spot pattern, these new chips were using a linear flow pattern mimicking the core-plug flooding geometry. The wettability of the micro models was successfully modified using chemicals. The comparison of flooding results from micro models and the core plug is documented in the project report, as well as the numerical simulation of the chips and the core plug experiment. The rheological database was extended by various HPAM and xanthan polymers. Particular focus was given to viscoelastic properties and the visualization of stream lines during the polymer flow through the chips.