--> Abstract: Rock Physics Modeling and Seismic Attributes of Carbonate Rocks in the Nesson Anticline, North Dakota; #90063 (2007)

Datapages, Inc.Print this page

Rock Physics Modeling and Seismic Attributes of Carbonate Rocks in the Nesson Anticline, North Dakota

 

Bandyopadhyay, Kaushik1, Tapan Mukerji1, Gary Mavko1, Charlie West2 (1) Stanford University, Stanford, CA (2) Hess Corporation, Houston, TX

 

Carbonates usually show high spatial variability of rock properties. Careful modeling that integrates large scale structural and stratigraphic features with pore scale rock properties is important in delineating the reservoir zones in such formations. In this paper we present rock physics based analysis of seismic properties in a dolomite formation in North Dakota. The reservoir rock is highly heterogeneous. The variability in the rock properties are mostly controlled by structural setting, stratigraphy and diagenesis. Two different pore types, vugy porosity and micro-porosity are present in the studied region. Vugs are open in the reservoir zones and filled with salt in the non-reservoir rocks. Acoustic properties of different pore types are studied at well log and seismic scale. Differential effective medium model is employed to model the effective seismic properties. Pore space stiffness is used as an additional parameter to explain the large variability in seismic velocities at a particular porosity. The structural setting and proximity to major faults are found to be important factors affecting the reservoir quality. Many of the non-reservoir rocks showing salt-plugged porosity are in close proximity to the large scale faults. It is hypothesized that vertical fractures associated with the major faults controlled fluid movement and resultant deposition of salts in the pore space. Incorporation of these fractures of scales larger than sonic log but smaller than seismic scale into the rock physics models turns out to be crucial in calibrating well data to the seismic. Finally we present post stack and inverted seismic attributes to differentiate the salt-plugged zones from good reservoirs.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California