Integrated Rock Physics and Seismic Modeling of Igneous Reservoirs

Summary Igneous reservoirs are receiving increased interest as an unconventional reservoir type, but are generally underexplored and poorly understood. These reservoirs show a wide range of possible responses in seismic and well data, leading to high risk in exploration. Here, we present initital results from the use of an adapted version of the Xu-Payne carbonate rock physics model to analyse laboratory and well data of igneous reservoir rocks. We investigate the effect of various geological factors including mineralogy, alteration and fracturing on the porosity-velocity relation, and the potential of the rock physics model to use these trends for igneous reservoir characterization. Finally, we integrate the rock physics model with seismic forward modelling of an igneous sill complex to illustrate the relationship between reservoir properties and seismic response. Although calibration of the model should be more consistent for future case studies, we can successfully link the effect of changing mineralogy, alteration and pore space characteristics to the expected seismic velocity. We show that even for similar amount of porosity, the dominant pore shape (fractures vs rounded pores) can strongly alter the seismic image of an igneous reservoir target.