Recognition technique of “bright spot” and its application to shallow oil & gas accumulations offshore in Structure X

Strong reflection axes are observed in the seismic profiles in the offshore area of the Structure X in the East China Sea. The strong reflections should not be regarded as bright features of oil and gas deposits, since the oil and gas reservoirs are shallowly buried in this region. There is lack of well data and samples and the correlation between strong reflection and oil-gas potential is not available. However, the seismic data of the target layer in the study area have good resolution and amplitude preservation indeed, so it is suitable for the " bright spot” identification. In view of this, we used a series of techniques, such as the forward modeling to distinguish the true and false " bright spots”, the AVO seismic attributes to recognize the " bright spots”, the gather-detection to verify the hydrocarbon potential of the " bright spots” and so on. Based on the integrated research, we summarized in this paper the responding characteristics of the " bright spot” to the type of hydrocarbon reservoirs in the target interval of the study area. According to the scale of gas-bearing sand bodies, this paper made an advice to the further exploration directions.