Print this pageAAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Integrated Reservoir Modelling of the Natih E Member at a Salt-Cored Carbonate Dome, Jebel Madar, Oman
(1) Geology and Geological Engineering, Colorado School of Mines, Golden, CO.
(2) Statoil Research Center, Statoil ASA, Bergen, Norway.
The Late Cretaceous carbonates of the Middle East include many prolific reservoirs. However, fracture heterogeneity, and porosity and permeability distribution are still poorly constrained. This study provides a three-dimensional evaluation of lithofacies, porosity, permeability and fracture distribution within the Cenomanian Natih E Member in a salt-cored dome (Jebel Madar) that crops out in the Adam Foothills of Northern Oman. A multi-layered, three-dimensional, integrated computer geomodel, was built from different component models. These component models are based on different data types and scales, and are interpreted and processed using multiple software packages.
To build the component models, a structural model was constructed based on field data that was digitized onto Quickbird imagery and draped on top of a Depth Elevation Model. A three-dimensional grid is generated from the structural model, which acts as the skeleton grid within the lithofacies, porosity, permeability, and fracture set models were populated. The lithofacies distribution is based on nine field-measured sections. The porosity and permeability distribution is based on QEMSCAN® analyses of field-samples at the measured sections. The fracture distribution is based on 21 field-measured fracture maps, and fracture interpretations on 5 photo-realistic LiDAR models.
The stratigraphic framework of the Natih E Member comprises three shoaling-upward fourth-order depositional cycles, and six carbonate lithofacies in three facies associations. These facies associations occupy a SW-directed mid-ramp position that comprised quiet subtidal shelf environments to both inactive and active shoal environments. The cycles are aggrading to prograding. Porosity and permeability distributions show no clear trend between facies or sampled locations, and average values are low (~3% and 0.01mD). The dominant fracture orientations are radial and concentric, related to local dome-formation. Fracture swarms are related to major faults.
The integrated geomodeling workflow is relatively simple, and is a useful way to model an analogue reservoir based on different data types and scales using multiple software packages. The quality of the geomodel is highly dependent on the quality of the base models on which data is digitized, and the limitations of the modelling software. Since the geomodel is built from separate component models, it is simple to increase the detail and quality of the integrated geomodel.