The shale gas of the Longmaxi group in the Zigong area of ​​Sichuan Basin was developed in a horizontal well. During the target of the horizontal well, there was no obvious labeling layer in the thick layer of the Longmaxi group. The vertical depth from the target is about 45 m. After the weight of the S1l11−4 layer is reduced by 15−30 m, it can lead to the Wufeng groups of the horizontal well-off target bottom and return to the well. Using the geological information of the pilot well to analyze the changes in the seismic facies caused by the changes in the thickness of the S1l11−4 layer, to clarify the characteristics of the thickness of the thickness of different strata. Based on instantaneous amplitude and waveform clustering methods, predict the thickness changes in the thickness of the S1l11−4 layer in a well area, thereby guiding the horizontal well to accurately enter the target. Compared with the characteristics of the S1l11−4 layer well measurement curve, it was found that it was thin from the small fault that caused the S1l11−4 layer to become thinner. Use the curvature to portray the small fault, accurately identify the distribution of the north east to small fault, and match the thin area of the S1l11−4 layer. The effective guidance of the shale gas horizontal wells in this research can accurately enter the target and reduce the risk of backfilling.