Volume Fraction Analysis of Two-Phase Flows in Fractures
Crandall, Dustin 1, Goodarz Ahmadi 1, Grant Bromhal 2, and Duane Smith 2
1Clarkson University, Mechanical and Aeronautical Engineering Department
2National Energy Technology Laboratory, U.S. Department of Energy
Rock fractures have been known to provide primary flow paths for subterranean fluid flows. The interaction between CO2 and liquid saturated reservoirs is an interesting area of research. This work attempts to provide an understanding of the processes involved and also to derive an empirical equation relating the pressure drop for multi-phase flow through fractures. Here the volume of fluid multi-phase model of FLUENT code is used to describe the flow.
The issues posed by carbon-dioxide sequestration are similar in nature to the study of reservoir flooding, especially when carbon-dioxide sequestration is used for enhanced resource recovery. This work presents a computational analysis of the percentage of in-place oil that is removed by an injected fluid through an idealized set of fractures with varying properties. Different aperture heights are compared against each other in an effort to quantify the effect that abrupt changes in height have on the flow properties. This is representative of the abrupt height changes seen in natural fractures, highly simplified in order to isolate the specific aspect of current interest.
Work thus far has shown that the velocity of the invading fluid has the most dramatic effect on removal efficiency, with flows above the creeping regime removing a smaller percentage of in-place oil. Varying aperture height is shown to affect the removal efficiency as well, with the most restrictive passages hindering the flow and creating areas of trapped in-place oil along the flow path.