HOW TO PREDICT OIL-GAS DELINEATION WITH SIMULTANEOUS INVERSION METHODS IN HIGH IMPEDANCE SAND : AS A PREDICTIVE HYDROCARBON INDICATOR

摘要

Simultaneous inversion is a seismic inversion method which uses angle gather data (near, mid, and far angle) that includes information on partial data stack angle from P wave and inverted using estimated wavelet resulting from each stack to obtain the information of Vp, Vs, Vp/Vs and density. This study used well log data, geological interpretation and partial stack seismic volumes to generate absolute P-impedance, S-impedance, Density and Vp/Vs models through Simultaneous Inversion technology that highly correlated to reservoir property. The Simultaneous Inversion workflow was adopted and rigorous quality controls were applied to provide high quality elastic rock property models calibrated to the well log data and consistent with the geological interpretation. The study showed that P-impedance and Vp/Vs volumes could be transformed into lithology probability to see uncertainty and confidence level of the interpretation For each input partial stack, a unique wavelet is estimated. All the models, all the partial stacks and all the wavelets are input to a single inversion procedure. Sensitivity analysis was conducted to determine the parameters which are sensitive for lithology changes or fluid changes in wells. The result of this cross-plot is a wet trend relationship, the deviation from this trend is the hydrocarbon. Transformation into the LMR can obtain the lithology distribution of sand Formation, as the cross-plot analysis parameter Mu Rho very sensitive to lithology variation and Lambda over Mu very sensitive to potential reservoir in Sand Formation.