Application of AVO Characteristics Analysis and Seismic Dispersion AVO Inversion to the Carbonate Hydrocarbon Reservoirs in Region Y of the Tarim Basin, China

Abstract

In recent years, breakthroughs in deep hydrocarbon exploration have been continuously achieved in the Tarim Basin of China. The Ordovician carbonate stratum has been shown to contain vast oil and gas resources. However, challenges remain in understanding the seismic response characteristics and accurately identifying the hydrocarbon reservoirs. These challenges can be attributed to factors including the significant burial depth of the target layers and complex geologic structures. To effectively support hydrocarbon exploration and resource assessment in the Tarim Basin, this study focused on the following three aspects in Region Y. First, according to the analysis of prestack amplitude versus offset (AVO) characteristics in well-adjacent seismic traces and seismic forward modeling, we demonstrated that different fluid-filled reservoirs have distinctly different AVO characteristics. This means that the hydrocarbon reservoirs in the study area can be identified by AVO inversion. Second, based on the theory that seismic waves exhibit amplitude attenuation and velocity dispersion when propagating through fluid-filled media, the seismic dispersion AVO inversion technique was developed to obtain equations for the attributes of primary (P) and shear (S) seismic wave dispersion. Finally, this technique was applied in Region Y and further verified using actual drilling data from single wells and well profiles. The application results demonstrate that hydrocarbon reservoirs can be effectively identified using this technique and provide a technical reference for reservoir identification in other areas of the Tarim Basin. The AVO characteristic analysis is the prerequisite for the successful application of this method; the key is to find accurate inversion equations and parameters to recognize the AVO response patterns in the study area.