Abstract:

Abstract: Marine carbonate reservoirs are characterized by high propensity for dissolution and filling and complexity of genesis and evolution. We performed description of sedimentary environment, study of forming mechanism and development models, and prediction of distribution of carbonate reservoirs in the CambrianOrdovician in Tarim Basin and the PermianTriassic in Northeastern Sichuan Basin, and came to the following three conclusions. First, the behaviors of carbonates dissolution are quite different depending on lithologies, structures, fluids and fillings as well as the system being open or closed. However, they still obey the law of “dissolution window”. Secondly，carbonate reservoirs are principally controlled by sedimentary environment and diagenetic process. Analysis of five influential factors including structures，stratigraphy，lithofacies，fluids and forming time shows that reservoirs in different areas and different layers are different in genesis，controlling factors and distributing characteristics. Thirdly，the geophysical prediction for carbonate reservoirs are confronted with complex surface conditions, complicated structures，great burial depth，complicated geometry and strong heterogeneity. However, the spatial distribution of highquality carbonate reservoirs can be predicted effectively by utilizing the integrated predicting methods including petrophysical characteristic analysis of logging data，processing of highresolution 3D seismic data，calibration of seismic data with well data, differentiation of geological and geophysical characteristics of different types of reservoirs，construction of the model of the geophysical response to carbonate reservoirs，demonstration of the discontinuity and irregularity of reservoirs，as well as quantitative calculation of the physical parameters and the hydrocarbon potential of carbonate reservoirs.

Key words: karst reservoir, dolomite reservoir, reefbank reservoir, forming mechanism, carbonates, rock, Tarim Basin, Sichuan Basin