ABSTRACT
The ANGUILLE MARINE field has been produced for 25 years. Implementation of water injection soon revealed complex reservoir mechanisms controlled by severe sedimentary heterogeneities.
The ANGUILLE Formation has been deposited in a deep-sea- fan environment (slope apron) with a low sand/shale ratio. In such an environment, the geometry of sandbodies controls the reservoir connectivity. Knowledge of this parameter is therefore critical in understanding flow mechanisms.
This paper deals with a multi-scale analysis of the heterogeneities (5 scales were studied), and the research of the best way to represent all the scales in the 3D modelling.
Sequence stratigraphy principles are applied successfully and allow the reconstitution of the ANGUILLE Formation history. In each defined time unit, a sequence analysis log data is used to divide the reservoir into four main types of turbiditic geometries (channels, lobes, slumps, laminated facies). Isovalue maps of lobe and channel frequency slow clearly the paleo-directions of sediment supply. These, together with the well data, constrained the generation of fine 3D models of heterogeneities (more than 2 millions gridblocks) using geostatistical techniques. The generated models proved to efficiently represent the reservoir, as confirmed by the drilling of a new well in the northern part of the field. The results of the full-field flow simulations raised several questions regarding both the geological model and the upscaling process. The use of partial models led to the conclusion that the aggregation rate should be optimized before using some geological characteristics (sedimentary bodies dimensions, elementary facies permeability,…) as parameters in the history matching process.
