3D seismic exploration technology with the mode of “Wide-azimuth

high-density and broadband” is widely used in the exploration of conventional and unconventional oil and gas. Technical effectiveness and economy are the two main factors restricting seismic exploration

especially unconventional oil and gas exploration（shale oil and gas

coalbed methane

etc.）

whose economy is the main influencing factor. Taking 3D seismic exploration for the shale gas with normal pressure in Wulong as an example

the successful 3D method of shale gas with low density and economy is introduced

and the purpose of reducing the exploration cost of 3D seismic data and improving the exploration effect is achieved. Combined with the similar conventional 3D seismic exploration examples in Taozidang area

the S/N ratio is evaluated and analyzed emphatically. It is pointed out that the application geological background with relatively simple structure

regional enrichment and strong reflective seismic interface

low density observation system with high cost performance

single shot record with high energy and SNR

and methods of improving S/N ratio and high-precision static correction for seismic exploration are the keys to the success of low density 3D shale gas. The application of deep well and large dosage saturation excitation to ensure the energy and S/N ratio of seismic acquisition data

improve the ratio of effective seismic record ratio

and the method and measure of field management are worthy of reference. Its successful experience has been widely used in 3D seismic exploration in Guihua and Yangchungou.