The 1

st

member of Permian Xiashihezi Formation (He-1) in Daniudi gas field

Ordos Basin

is braided channel deposits with large thickness.As heterogeneity of the gas layer distribution is strong

development of the gas reservoirs with horizontal wells is difficult.In order to increase the success rate of drilling"sweet spot"in this tight sandstone layer

we studied in detail the sedimentary facies and characteristics of the braided channel deposits in He-1 based on analyses of high resolution sequence stratigraphy and sedimentary system

and presented methods to integrate various seismic data into design of horizontal well trajectory

such as 3D seismic interpretation

waveform analysis

AVO gas detection and geo-statistical inversion.Among these seismic data

negative AVO gradient and geo-statistics inversion are the most important and can provide strong technical support to the development of the tight sand gas reservoirs with horizontal wells in Dajiudi gas field.The integration of sequence stratigraphy theory with geophysical prediction methods is an effective way to improve the success rate of "sweet spot"drilling in tight gas sandstone reservoirs.