Fluid prediction of carbonate reservoir based on PP- and PS-wave amplitude attribute

Abstract

Summary The deep and low porosity carbonate (dolomite) reservoirs develop in the central Sichuan Basin of Western China, and the reservoirs are filled with different types of fluids (gas, water, bitumen). We first analyze seismic response difference between PP- and PS-wave, and then combine seismic forward modeling and logging data to carry out fluid identification using the amplitude difference of PP- and PS-wave. Based on comparisons, we observe that, the gas-bearing layer exhibits strong peaks on PP-wave and relatively weak peaks on PS-wave, which are opposite to the condition of water-saturated layer. In the case that the reservoirs are filled with bitumen, both PP- and PS-wave exhibit strong peaks, and the PP-wave reflection amplitudes are stronger than PS-wave. We verify that PS-wave characterizes the distribution of porous dolomite reservoirs better than the PP-wave. The maximum peak amplitude difference between PP- and PS-wave data is a viable and reliable attribute to distinguish gas-bearing and water-saturated layers in the deep dolomite reservoirs.