3-D Micromodel for Visualization & Experimental Analysis of Flow Behavior, Surface Tension and Polymer Concentration on Enhanced Oil Recovery

Abstract

Oil recovery is a complex process involving physical and chemical interactions within the pore spaces of the reservoir. The oil recovery improves by injecting viscous and wettability-altering fluids into the reservoir. The present work aims to study the improvement in the recovery using surfactant polymer (SP) slug and discuss the mechanisms behind the oil mobilization process by visualizing the oil recovery using a glass tube filled with glass beads. Fluids were injected using a syringe pump, and the interaction of the fluid was visualized using a high-speed camera. Initially, the oil was displaced using brine which was followed by the injection of SP slug formulated using Sodium Dodecyl Sulphate (SDS) and Poly Acrylamide (PAM). The effect of the composition of the slug was studied at different concentrations 125ppm, 250ppm, 375ppm, and 500ppm. After that, the effect of flow rate of SP slug on the oil recovery process was explored. Colored non-interacting dyes aided the visualization in the glass model. Images of the oil recovery process were captured to examine the fluid displacement mechanism during SP flooding. The total oil recovery increases from 73.33% to 83.33%, as the polymer concentration was increased gradually from 125 ppm to 500 ppm at a flow rate of 100 µL/min which further increases to 90% for 500 ppm slug at 500 µL/min of flow rate. High-quality magnified images from the camera captured the flow path of each fluid injected through the glass bead-packed channel. The effect of various forces like capillary, gravity, and viscous forces were visualized and analyzed. The pore throat and pore-diameter calculations were done using the software. The low viscous slug was subjected to higher gravity force, rendering it ineffective in displacing the oil present at the channel's top. The gravity segregation was overpowered by high viscous slugs that mobilized the oil present in the channel. The understanding and analysis of the fluid motion under oil-brine interaction and SP slug-oil interactions was studied. The study helps improve the techno-economic feasibility of the whole recovery process by limiting the use of chemicals and maximizing the oil recovery in a controlled manner.