Integrated Modeling of a Highly Structural and Complex Reservoir Where the Normal Modeling Rules Do Not Apply,Cerro Fortunoso.

摘要

Cerro Fortunoso is a field with excess of 30 years production history which lies in Mendoza Province, Argentina.A study was undertaken to establish if the existing five injection well waterflood pilot could be expanded to encompass the rest of the 240 well field and that the necessary investment for facilities could be justified. A detailed look at the field quickly shows why waterflood has only been tried in a very limited fashion. The Cerro Fortunoso anticline is an asymmetric,west verging structure orientated NNE-SSW and affected by different kinds of faults located in a fold and thrust belt.The anticline geometry is affected by low and high angle reverse faults generating an eastern flank that dips up to 80°at the central part of the fold. An initial static model representing the structural complexity and the 17 cycle high resolution stratigraphic framework was constructed.However interpretation of RFT data demonstrated that flow was controlled by thin sandstones lying in the same high order cycles but which were pressure isolated from each other,hence for secondary recovery it was necessary to understand the areal extent and connectivity of these sand bodies.Additionally the very high angle of dip and the heterogeneous fluvial reservoir meant that a sandstone body could plausibly connect with a number of different sandstones on a neighboring well,leading to a situation where different correlations schemes were plausible. This paper details how the uncertainty in the correlation of the sand bodies was reduced by integration of static and dynamic data.A number of correlation scenarios were constructed in the static model and subsequently evaluated by dynamic testing against the production and pressure data.Through iterations, a dynamic model was subsequently constructed that matched production and pressure history and in which it was possible to determine which sands were more critical to the success of any waterflood.