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Speaker: David Close
Presented by ASEG Queensland Branch. The talk will follow the ASEG Queensland Branch Annual General Meeting.
Please RSVP to Megan Nightingale by 5pm Monday 31st March to attend this meeting.
About the Speaker
David holds a Ph.D. from the University of Oxford, where he studied as a Rhodes Scholar, and a B.Sc. from the University of Tasmania. David worked in Mexico, U.S.A and Canada for Schlumberger and Apache Canada prior to joining Origin in Brisbane as a geophysicist, where he specializes in AVO studies and inversion, and unconventional resource evaluation. Currently he is the Manager of Unconventional Resources for Origin and is focused on unconventional hydrocarbon exploration across frontier basins of Australia. David is a member PESA, ASEG, SEG, CSEG and AAPG.
Talk Overview
Geophysicists have leveraged the natural geometry of multi-fold seismic data to extract information about the shear properties of rocks for a number of decades using amplitude variations with offset or angle (i.e. AVO). AVO methods exploit variations in seismic compressional and shear wave velocities or impedances to infer changes in lithology, pore fluids or other changes in the subsurface. Correct, or indeed viable, interpretation requires both an understanding of the regional and local geology in addition to an understanding of the rock physics that underpin the seismic response. A number of industry standard methodologies for interpretation are commonly utilised, with interpreters leveraging existing paradigms regarding the meaning of certain seismic and AVO characteristics.
Understanding velocity or impedance measurements in Lame parameter terms of incompressibility (l) and rigidity (m) provides an alternative interpretation methodology (Goodway et al., 1997). In addition to these two parameters Goodway et al. (1997) introduced two new attributes, LambdaRho (lr) and MuRho (mr) or Lamé impedances, that could be calculated using AVO and referred to the method as Lambda-Mu-Rho or LMR.
Rock physics model (RPM) based interpretation templates for LMR or other elastic parameters can be used to facilitate interpretation and comparison of log or seismic derived elastic properties. In this paper RPM templates are used in a conventional and unconventional workflow to illustrate the power of using LMR in addition to ‘standard’ rock physics templates.
