High-Resolution, Microvisual Study of High Mobility Ratio, Immiscible Displacements
Abstract/Contents
- Abstract
- Fifty percent of worldwide oil production is recovered via a waterflood process. Waterflooding of lighter oils is considered to be stable displacement processes that is well described by the Buckley Leverett equation and Darcy's Law. Consequently, reservoir simulation predictions are more likely to predict actual production. Waterflooding of heavy oils, does not exhibit a BL displacement, and reservoir simulators do not as accurately predict actual production in these waterflood processes. The purpose of this investigation is to improve our understanding of immiscible displacements during forced imbibition of heavy oils as well as to relate both mobility ratio and injection rate to displacement front stability, breakthrough recovery time, breakthrough recovery and ultimate recovery. Toward this goal, forced water imbibition experiments were conducted in a micromodel whose homogenous pore space is geometrically and topologically similar to Berea sandstone. High-resolution, microvisual data, in the form of photographs and video footage, describes the advancing front at the pore and the ensemble pore network scale. Digital analysis of pore-scale photographs determines initial water saturation, water saturation of the swept region at breakthrough, area swept at breakthrough, and residual oil saturation. The experimental parameters explored include oil viscosity, water injection rate, presence/absence of connate water, and uniformity of initial water saturation. It was observed that that in high viscosity ratio waterfloods stability of displacement is dependent upon uniformity of initial saturation conditions and flow rate. Sweep efficiency at breakthrough is inversely proportional to flow rate and related to uniformity of initial conditions. Ultimate recovery factor is not a function of injection rate, but cumulative injection required to reach residual oil conditions is a function of injection rate. At insufficient flow rates, capillary forces dominate over viscous forces, and the cumulative injection to reach residual oil conditions increases significantly, despite the higher sweep efficiency achieved at breakthrough. Thus, from an optimization standpoint, the micromodel experiments demonstrate the fundamental importance of both characterizing the pore medium accurately and selecting an injection rate that yields the lowest cumulative water-oil production ratio. Repeat trials would be useful for corroborating the initial trends observed in this study.
Description
| Type of resource | text |
|---|---|
| Date created | June 2008 |
Creators/Contributors
| Author | Inwood, Sarah |
|---|---|
| Primary advisor | Kovscek, Anthony R. |
| Advisor | Castanier, Louis |
| Degree granting institution | Stanford University, Department of Petroleum Engineering |
Subjects
| Subject | School of Earth Energy & Environmental Sciences |
|---|---|
| Genre | Thesis |
Bibliographic information
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Preferred citation
- Preferred Citation
- Inwood, Sarah. (2008). High-Resolution, Microvisual Study of High Mobility Ratio, Immiscible Displacements. Stanford Digital Repository. Available at: https://purl.stanford.edu/zz987rw7807
Collection
Master's Theses, Doerr School of Sustainability
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