Enhanced Heavy Oil Recovery by Calcium Hydroxide Flooding with the Production of Viscoelastic Materials: Study with 3-D X-Ray Tomography and 2-D Glass Micromodels

In this study, the performance of calcium hydroxide (Ca(OH)(2)) flooding (CHF) was investigated with three-dimensional (3-D) experiments with microcomputed tomography and two-dimensional (2-D) micromodel experiments. In 3-D experiments for CHF, two stages of displacement occurred at high capillary numbers. First, streak-like patterns of viscous fingering developed up to the exit of the packed bed. After that, a stable displacement front propagated in the flow direction and resulted in an oil recovery of >50% of the initial oil in place. During the propagation of the stable displacement front, a high-pressure drop was established along the porous media. If CHF is followed by water flooding (WF), the stable front did not propagate and oil production declined promptly. CHF oil recovery is higher by approximately 30% than that of WF for all permeability ratios of heterogeneous layered porous media. We successfully demonstrated that CHF could improve significantly in homogeneous porous media and heterogeneous layered media. 2-D micromodel experiments suggest that a ganglion of Ca(OH)(2) blobs and folded membranes pushed out heavy oil at pore scale in a stable displacement front.

Automated summary

The study showed that calcium hydroxide flooding significantly improves oil recovery, especially in heterogeneous porous media. However, if water flooding is conducted afterwards, oil production will decline promptly.