Seismic exploration method for shale gas in water-rich thick gravel layer coverage area

The invention provides a seismic exploration method for shale gas in a water-rich thick gravel layer coverage area. The method comprises the following steps: obtaining buried depth condition data of a gravel layer top boundary in an exploration area through manual field trial drilling; investigating condition data of a low-speed zone in an exploration area to obtain a pore-forming process and a test excitation well depth; the drilling depth is achieved through a high-power mountain drilling machine, and blended slurry is used for well cementation and lubrication during drilling; a PVC casing pipe is put down when drilling is conducted to the preset depth; performing a test before seismic exploration acquisition, performing a multi-well combination test, a test for receiving different detectors, a test for testing different arrangements and an interference wave survey, ensuring excitation energy by multi-well combination excitation in a pore-forming difficult area, and increasing shot points to further improve