In this study for the first time we generalize streamline models to compressible flow using a
rigorous formulation while retaining most of its computational advantages. Our new formulation
is based on three major elements and requires only minor modifications to existing streamline
models. First, we introduce a relative density for the total fluids along the streamlines. This
density captures the changes in the fluid volume with pressure and can be conveniently and
efficiently traced along streamlines. Thus, we simultaneously compute time of flight and volume
changes along streamlines. Second, we incorporate a density-dependent source term in the
streamline saturation/composition conservation equation to account for compressibility effects.
Third, the relative density, fluid volumes and the time-of-flight information are used to
incorporate cross-streamline effects via pressure updates and remapping of saturations. Our
proposed approach preserves the 1-D nature of the conservation calculations and all the
associated advantages of the streamline approach. The conservation calculations are fully
decoupled from the underlying grid and can be carried out using large time steps without gridbased
stability limits.
We also extend the streamline simulation to compositional modeling including
compressibility effects. Given the favorable computational scaling properties of streamline
models, the potential advantage for compositional simulation can be even more compelling.
Although several papers have discussed compositional simulation formulation, they all suffer
from a major limitation, particularly for compressible flow. All of the previous works assume,
either explicitly or implicitly, that the divergence of total flux along streamlines is negligible.
This is not only incorrect for compressible flow but also introduces inconsistency between the
pressure and conservation equations. We examine the implications of these assumptions on the
accuracy of compositional streamline simulation using a novel and rigorous treatment of
compressibility. We demonstrated the validity and practical utility of our approach using synthetic and field
examples and comparison with a finite difference simulator. Throughout the validation for
compositional model, we found out the importance of finer segments discretizations along
streamlines. We introduce optimal coarsening of segments to minimize flash calculations on
each segment while keeping the accuracy of finer segments.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4863 |
| Date | 25 April 2007 |
| Creators | Osako, Ichiro |
| Contributors | Datta-Gupta, Akhil |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 1604006 bytes, electronic, application/pdf, born digital |
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