Optimizing the Remaining Potential of Carbonate Reservoirs through an Integrated Rock Physics Study: An Example from the Miocene Carbonate

Mohammad Yamin Ali¹, M. Razali Che Kob¹, Sigit Sukmono², and Bagus Endar^2
1PETRONAS, Kuala Lumpur, Malaysia
²Institute Technology Bandung, Bandung, Indonesia

The Miocene carbonates are the main producers in Southeast Asia, Middle East and North Africa. In light of the importance of recovery and heterogeneity issues in carbonates, the integrated rock physics study was conducted to establish a relationship between the seismic and production properties for better prediction of carbonate reservoirs.
The results show that the S-Impedance, Mu-Rho, Vp, and AI are the best elastic property to discriminate lithologies. The Lambda-Mu-Rho and Vp clearly differentiate the tight from porous facies, The tight facies has higher readings than the porous facies. Mu, Rho, S-Impedance and Vs discriminate the porosity types well.
Pore-fluids are well differentiated by Mu and Mu-Rho. Brine has the highest Mu and Mu-Rho values, followed by oil and gas. The Vp is extremely sensitive to pore and effective pressures.
AVO analysis shows that Vp-Vs relationship is linear and the best-fit equation lines vary at different pressure conditions. Pore pressure increase will linearly decrease the Vp and Vs but overburden pressure increase will linearly increase the Vp and Vs. The change in Vp-Vs gradient due to a change in pore pressure is bigger than the change in overburden pressure.
Time-lapse seismic analysis shows that it is feasible to monitor the changes in water saturation and pore pressure. The decrease in water saturation and the increase in pore pressure will slow down the seismic wave velocity, extend the travel time, and decrease the amplitude of first break.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece