Abstract: The stratigraphic trap idenification is becoming more and more difcult with progressing petroleum exploration in Junggar basin. How to find the low-amplitude traps in it? Taking P-5 Wellblock in Junggar basin as an example, this paper examines the inconsis-tence between drilling and seismic interpretation for its low-amplitude trap identification, and includes the detailed analysis of subsurface velocity feature and seismic velocity data and the development of the velocity model. With the model showing forward modeling and veloc-ity field modeling, remapping of the structure in P-5 Wellblock is made. The result shows that the existing trapping area becomes larger than before, and high spot moves four km toward southwest, which has been confirmed by drilling.

Key words: Junggar basin, structure, trap, seismic wave velocity, model