*4.2. Prestack Field Data*

The SPRT*Lq*<sup>1</sup> − *Lq*<sup>2</sup> method was further tested with multi-shot prestack field data. In order to comprehensively evaluate the multiple suppression effect, we used a 3D method to display the multi-shot data volume, then analyzed the effectiveness of the method from the time slices, the common middle point gathers and the common offset gathers.

Figure 10a is original data, and multiples can be clearly seen at the arrow position in the figure. Figure 10b,c are the multiple attenuation results obtained by the LSPRT and the SPRT*L*<sup>1</sup> methods; Figure 10d is the result obtained by the SPRT*Lq*<sup>1</sup> − *Lq*2. Overall, all three methods suppress multiples, but the effects are different. In Figure 10b,c, it can be obviously observed from the time slice that a certain amount of the primary energy is lost when multiples are suppressed. In the CMP gathers the multiples of far offset are sufficiently suppressed by SPRT*Lq*<sup>1</sup> − *Lq*2, as indicated by the arrow. In the common offset gathers, the effectiveness of the SPRT*Lq*<sup>1</sup> − *Lq*<sup>2</sup> method is demonstrated by the continuity of the seismic events. This method has a sparser representation of the seismic data and fully retains the characteristics and information of the primaries, so as to improve the continuity of the seismic events.

**Figure 10.** Multiple attenuation result: (**a**) pre-stack real data; (**b**) LSPRT method; (**c**) SPRT*L*<sup>1</sup> method; (**d**) SPRT*Lq*<sup>1</sup> − *Lq*<sup>2</sup> method. The red arrows indicate the cleaner multiple attenuation in the Figure 10d.

Figure 11 shows the stack section after multiple attenuation by three methods. The residual of multiples leads to the discontinuity of the events of the primaries (black rectangle), which increases the difficulty of subsequent interpretation. The continuity of the seismic events is obviously enhanced in the stack sections using the method presented in this paper, and the effect of multiple attenuation between 0.5 s and 1 s has a remarkable effect. In addition, as can be seen by the black arrow region of Figure 11d, there is almost no multiple energy compared to Figure 11b,c.

**Figure 11.** Multiple attenuation result: (**a**) stacked real data; (**b**) LSPRT method; (**c**) SPRT*L*<sup>1</sup> method; (**d**) SPRT*Lq*<sup>1</sup> − *Lq*<sup>2</sup> method. The black arrows indicate the continuity of the seismic events are improved in the Figure 11d.

Therefore, the SPRT*Lq*<sup>1</sup> − *Lq*<sup>2</sup> method has some advantages in suppressing multiple reflections and retaining effective reflections.
