Turbidite Reservoir Representation for Flow Simulation

Regis K. Romeu¹, Paulo L. Paraizo¹, Marco A. Moraes¹, Claudio C. Lima¹, Flavia P. Silva¹, and Gilberto M. Ragagnin^2
1RESEARCH CENTER, PETROBRAS, Rio de Janeiro, Brazil
²EXPLORATION&PRODUCTION, PETROBRAS, Rio de Janeiro, Brazil

Reservoir flow simulation involves two aspects: a functional model (flow equations and numerical methods) and a representation model (related to the reservoir description). Commonly, the latter is the most critical one. Reservoir representation is different from reservoir characterization, since its main issue is not describing the reservoir in the most exhaustive and detailed form, but rather the challenge of incorporating the relevant information into the flow simulation model. It has to consider the syntax of the flow simulation methods and the relative impact of geological (and fluid) characteristics on the simulation results. Reservoir representation constitutes the bridge between reservoir characterization and flow simulation.

This paper presents selected results from several studies of turbidite reservoirs, in which the following steps were taken: (1) the identification and representation of critical depositional heterogeneities; (2) assignment of transmissibility multipliers across partially sealing faults; and (3) incorporation of production data in reservoir flow models. Seismic geomorphology analysis integrated with outcrop studies was used to identify the critical depositional heterogeneities, whose impact on fluid flow was tested using a series of synthetic models. Faults patterns were identified at the subsurface and their impact evaluated using in situ stress information, production data and outcrop analogs. Finally, observed production and pressure data were integrated using assisted history matching.

Such an integrated approach increased the precision of flow simulation models. The study clearly shows that reservoir flow modeling, and hence the understanding and adequate representation of reservoir connectivity, more than a multidisciplinary task, is an interdisciplinary task, in which is essential to fill the gaps between different disciplines.

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas