1. An Integrated Methodology Quantifying the Links Between Rock Physics- and Geochemical- Properties in Organic-Rich Shales
Amos Nur, Department of Geophysics, Stanford University, Stanford, CA
Organic-rich shales are intrinsically heterogeneous and complex rocks in which organic matter may differ in amount, quality, and maturity. We still lack fundamental relationships relating the maturity of the organic fraction and the rock-physics properties used to support seismic exploration.
A comprehensive laboratory study on organic-rich shales was undertaken to
understand how properties such as maturity expressed as vitrinite reflectance controls seismic wave propagation and anisotropy. We complemented traditional rock-physics measurements with the analysis of images obtained via confocal laser scanning microscopy (CLSM).
50 MPa
5 MPa
Elongated regions of green and red fluorescence indicating microgeometry of liptinite macerals obtained from 3-D CSLM data for a Monterey shale sample. Stack size is about 636 x 636 x 55 mm.
For maturities less than 0.65 (from immature to peak mature rocks), rocks exhibit a low pressure-sensitivity (velocity and anisotropy) but increasing magnitude of anisotropy with increasing Ro%; for maturities greater than 0.65, rocks show a higher sensitivity of velocity to pressure and decreasing magnitude of anisotropy.