Abstract：As main seismic source, air-gun or air-gun array is used in marine seismic exploration. Air-gun array composed of a number of air-guns has certain length and width. With the restriction of ship and field conditions, a designed air-gun array is difficult to form a circular symmetry space. All these factors make it hard to meet point source hypothesis. So wavelet energy of the air-gun array always changes with transmission direction. Based on the principle of air-gun far-field signature composition, we deduce in this paper a method of calculating the air-gun array directional energy by introducing 3-D polar coordinate system, the space layout of air-gun array, and ghost. With this method, we analyze the relations between air-gun array signature and lateral and vertical azimuths, and the energy distribution of the signature.
