SPE Journal
Volume 15,
Number 2,
June 2010,
pp. 454-470
Summary
Tracers are widely used to increase the understanding of fluid flow; they
can be used to label injection fluids, hence, well connections and fluid
patterns can be established when the tracer appears in production wells. Tracer
data contain valuable information but are often underexploited.
This paper presents methodology for assimilation of tracer data for
reservoir model updating using the ensemble Kalman filter (EnKF). The presented
assimilation methodology is generally applicable for all types of tracers, but
the example used for demonstration focuses on gas tracers. Contrary to water
tracers, which can be either nonpartitioning or partition between (oil and
water) phases, gas tracers always partition between the oil and gas phases.
This oil/gas partitioning is accounted for in the presented tracer transport
modeling. The EnKF has recently gained popularity as a method for history
matching. The EnKF includes online update of parameters and the dynamical
states. An ensemble of model representations is used to represent the model
uncertainty.
The value of tracer data in the EnKF approach is demonstrated on a
North-Sea-based example. The permeability and fault transmissibility multiplier
of a reservoir are estimated by EnKF. This example shows that tracer data can
be used successfully in an EnKF-based automatic updating scheme. Potential
misinterpretations of gas tracer data if their partitioning is neglected is
highlighted by comparing results from simulation cases where partitioning is
neglected to simulation results where partitioning is accounted for.
© 2009. Society of Petroleum Engineers
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History
- Original manuscript received:
29 April 2008
- Meeting paper published:
20 April 2008
- Revised manuscript received:
4 June 2009
- Manuscript approved:
8 June 2009
- Published online:
2 December 2009
- Version of record:
17 June 2010