Summary
This paper describes an efficient numerical scheme for nonisothermal
compositional flow coupled to chemistry. An iterative
implicit-pressure/explicit-composition (IMPEC) method is applied to solve the
flow problem using a volume-balance-convergence criterion. A backward-Euler
mixed finite-element method (FEM) with lowest-order RT0
elements is applied to solve the pressure equation, and a component local
mass-preserving explicit scheme is used to update concentrations. Chemical
reactions are solved using explicit Runge-Kutta (RK)
ordinary-differential-equation (ODE) integration schemes. A higher-order
Godunov method and a backward-Euler mixed FEM are applied for thermal advection
and conduction, respectively, in a time-split scheme.
One of the major applications of the method is in the modeling of
field-scale carbon dioxide (CO2) sequestration as an
enhanced-oil-recovery (EOR) process or for containment in deep saline aquifers
where chemical reactions and temperature variations may have an effect on the
flow and transport of CO2. Leakage patterns when CO2 is
injected near leaky abandoned wells, the displacement of methane from depleted
gas reservoirs, and accurate modeling of geochemical reactions involving
injected CO2 are other applications of interest.
Results of a benchmark problem in multiphase flow with several hydrocarbon
components in formations with highly heterogeneous permeability on very fine
grids, as well as a large-scale parallel implementation of modeling
CO2 sequestration, are presented to justify the practical use of the
model. A parallel efficiency of approximately 80% was observed on up to 512
cores in the benchmark study. Results from a problem simulating injection of
CO2 in deep aquifers including nonisothermal and chemical effects
are also presented. The results indicate a good agreement of the solutions with
published data, where available.
Numerical modeling and simulation of CO2 sequestration plays a
major role in future site selections and in designing storage facilities for
effective CO2 containment. The main contribution of this paper lies
in providing a parallel and efficient method of simulating challenging
compositional flow problems, such as in the study of CO2
sequestration, as well as flow coupled to thermal and geochemical effects.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
3 November 2008
- Meeting paper published:
2 February 2009
- Revised manuscript received:
4 June 2010
- Manuscript approved:
8 July 2010
- Published online:
29 December 2010
- Version of record:
17 June 2011