Integrating Rock Physics and Seismic Methods to Reduce Uncertainties in Permeability Modeling of an Exploratory Carbonate Oil Field

Ebrahim Hassanzadeh¹, S. Saleh Hendi², and Ayato Kato^3
1 Research Institute of Petroleum Industry, Tehran, Iran
² Research Institute of Petroleum Industry,
³ JNOC- Technology Research Centre, Tokyo, Japan

Permeability is one of the most important factors for quality assessment of a carbonate reservoir; furthermore, mapping the permeability over an exploratory carbonate oil field is of essential importance. The area under study is a newly explored oil field containing carbonate reserves of Cretaceous age, located in the southwest Iran and covered by 3D seismic data. It is well known that carbonates have different types of porosity that affect permeability and seismic wave propagation; therefore, these facts can be used for integrated permeability studies of such type of reservoirs. One of the key tasks of our study was to find relationships between seismic velocities from one side, and porosity and permeability of core samples from the other side. In this manner, a 3D porosity volume was created over the interest area by correlating well and seismic data, also a model have been derived to estimate Vs from Vp based on the laboratory velocity measurements and consequently Vp/Vs volume was calculated using this model. Porosities of core samples were cross-plotted versus Vp/Vs ratios, whereby permeabilities considered as third dimension of the plot. Laboratory observations indicate that samples of high Vp/Vs ratio and high porosity have high permeability values, too. Permeability model was achieved by overlying porosity and Vp/Vs volumes and classifying the resulting volume to the different permeability ranges. The resulting model indicates an improved estimation of the reservoir permeability in compare to the geo-statistical methods.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005