Stochastic
Fault Seal Analysis and Reservoir Simulation for Fields with Thin Layers and
Many Faults (Best of EAGE)
Shang, B.Z1, H.D.
Yang2,
Traditional fault seal analysis requires
deterministic structural and stratigraphic models and
significant fluid flow data for transmissibility calibration. For multi-faulted
reservoirs with large structural and stratigraphic
uncertainties and little dynamic data, traditional method fails to capture the range
of production scenarios. This paper proposes a new method to capture the range
of possibilities via stochastic analysis in juxtaposition, shale gouge ratio,
and fluid flow. First, we gather the stratigraphic
and structural information and to generate the parameter ranges, such as
reservoir layer thicknesses, net-to-gross ration, number of layers, etc. Then,
many juxtaposition realizations are created from these parameters. When
reservoir zone thickness is greater than the fault throw, the shale gouge ratio
is reduced to a function of net-to-gross ratio alone. Afterward, we construct
the probability distribution function of cross-fault transmissibility by
combining juxtaposition, shale gouge ratio and dynamic data. Finally, the
transmissibility probability is provided to the simulator for reservoir
performance simulation. This procedure has been applied to the appraisal of an
offshore oil field that has many faults and subseismic
reservoir layers. The procedure is demonstrated in 1 D but can be expanded into
3D by allowing the controlling parameters to vary with location.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California