Carbonate Reservoir Characterization and Simulation: from Facies to Flow Units, Case Study from Tarim Basin, China

Ran Zhang
University of Houston, Houston, TX

Lun Nan field is an upper Cambrian to lowest Silurian carbonate buildup in the Tarim Basin of western China. Carbonates from this reservoir were deposited in a variety of marine environments ranging from tidal flats to reefs. The original texture and porosity of the reservoir carbonates are highly variable depending on the depositional environments. Both the depositional and diagenetic processes at the scale of high-resolution sequence stratigraphy (parasequence level) have the strongest effect on carbonate-reservoir flow units and their petrophysical properties. Data used in the study include logs, cores, borehole image logs, and 3-D acoustic impedance values from inversion of seismic data. Outcrop studies have also been used to understand the performance of this reservoir, which can provide stratigraphic and sedimentologic information. High-frequency sequence-stratigraphic interpretation, guided by a depositional model derived from description of cores and outcrops, was accomplished using a necessary combination of well logs and seismic data. The sequence-stratigraphic interpretation served as input for the multiple iterative seismic inversions and provided the framework for the integrated 3-D geologic model. An object-based stochastic approach was used to build 3D stratigraphic and lithofacies frameworks and model the external geometries of this carbonate reservoir. Internal geometries were incorporated by building 3D porosity, permeability and water saturation distribution models using various stochastic simulation methods. Geostatistical models were verified, selected and extracted to upscale for flow simulation study. The integrated reservoir characterization provides a basis for improving reservoir evaluation, enhancing production management, and improving understanding of the depositional controls on this carbonate reservoir.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece