Summary
Detailed compositional simulation of a giant reservoir with many components
is not practical. However, detailed multimillion-cell black-oil simulation of
giant reservoirs is now quite feasible. In this work, we apply an efficient
method to generate the compositional rates from a black-oil simulation of the
giant Shaybah field.
In situations in which the reservoir recovery mechanism is not dominated by
compositional effects, an equation-of-state (EOS) -based stream-conversion
method can be used. This stream-conversion method relies on the fact that when
laboratory pressure/volume/temperature (PVT) data measured on available
well-stream compositions are used to generate the black-oil PVT tables, some of
the compositional information is lost. The stream-conversion model retains this
valuable compositional information and applies it to each producing-well
completion in the black-oil simulation at every timestep.
As proof of the concept, the stream-conversion method was applied to a
black-oil simulation and to a limited (eight-component) compositional
simulation to generate a 17-component compositional stream, and the results
were compared to the respective full EOS compositional simulation for a
relatively small sector (250,000 cells) of the giant Shaybah field. The
compositional stream rates are in excellent agreement with the stream-converted
black-oil results. As would be expected, the computational costs of using the
EOS-based compositional simulator (with 17 components) are in excess of 40
times the black-oil-simulation time for the small-sector model. In general, the
stream-conversion method can be used to generate the dynamically varying
compositional streams from any black-oil simulation for use in the design and
operation of surface facilities and in calculating the amounts of a certain cut
[e.g., natural gas liquids (NGL)] from the production streams.
Introduction
Recent advances in parallel-reservoir-simulation technology have made it
feasible to model the performance of giant hydrocarbon reservoirs with
simulation models that retain the full geologic-model resolution. These
multimillion-cell simulation/geologic models, when carefully conditioned to
engineering data, lend themselves to rapid history matching, despite their
size. More importantly, they are used actively in optimizing field development
with more confidence and in day-to-day reservoir management.
The above-mentioned multimillion-cell simulation models use a black-oil
treatment of the hydrocarbon fluids. Where compositional treatment of the
hydrocarbon fluids is desired, a conventional full EOS-based compositional
simulation of a giant hydrocarbon reservoir with many components is not yet
practical. In this work, we apply an efficient method to generate the
compositional rates from a black-oil simulation of the giant Shaybah field. The
theoretical basis for this method is presented in detail in Ref. 7. Herein, we
present only the pertinent information to elucidate its application in this
work.
© 2005. Society of Petroleum Engineers
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History
- Original manuscript received:
28 January 2004
- Revised manuscript received:
18 February 2005
- Manuscript approved:
30 March 2005
- Version of record:
15 August 2005
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