An accurate understanding of the internal architecture of a reservoir is required to improve oil recovery forecasts.
This article describes a software which gives 3D images of this architecture using conditional geostatistical simulations and provides tools to study the influence of these lithological descriptions on fluid flow behavior.
This software establishes the link between wells data and fluid flow reservoir simulators. Each step of this interactive and graphic system is explained here:
geological and geostatistical analysis to characterizea suitable model for the following steps,
conditional geostatistical simulations giving a lithological description of the internal heterogeneities onhigh resolution grids,
quantification of the reservoir assigning petrophysical values to each lithofacies grid cell (porosity and absolute permeability tensor),
scaling up methods computing in a cost effective way the averaged petrophysical values associated to reservoir simulator grid cells.
This new software concept which integrates multidisciplinary methods helps production geologists, geostatisticians, applied mathematicians and reservoir engineers to work in the same environment.
Current efforts to maximize oil production are becoming increasingly dependent on geological reservoir characterization. A major reason for poor recovery efficiency is the presence of geological heterogeneities which cause highly non-uniform fluid flow patterns and incomplete oil drainage.
So reservoir engineering studies should take into account as much available information as possible in order to improve the production forecasts. These extra data come from several disciplines and in practice, it is important to have a software which can handle them effectively.
The Heresim Group is working on a methodology to improve the internal architecture of reservoirs in fluvio-deltaic dept sits using geostatistics. The application of these methods undergoes the development of integrated softwares. A 2 dimension version of the software has been developed and here we describe the 3 dimension one: HERESIM 3-D.
The aim of this software is to start with well data and produce results which are directly usable by reservoir fluid flow produce results which are directly usable by reservoir fluid flow simulators, taking into account the geological interpretation of the reservoir.
This software is designed as an interactive program and relies on an existing package for data handling called "Magma". The Magina data base has been especially developed to deal with well data and big grid data sets. It is very important to be able to perform complex selections on the data to get statistics quickly and to store the huge output data sets (millions of cells) in an efficient way. HERESIM 3-D is provided with modern tools like on-line help and journal files and can be run on numerous types of computers. Many of the outputs are color graphics and need a graphical terminal for convenience.
The software is divided into five parts:
Data read and geological definition
Lithofacies simulation and visualization
Petrophysical value assignation
Mesh for reservoir simulators