Some breakthroughs have been made in the exploration of tight sandstone oil reservoir in Chang-8 Member of Yanchang Formation in Xiasiwan Oilfield recently. However

as the basic geological study of Chang-8 Member is relatively weak and the hydrocarbon accumulation condition is complex

the main controlling factors of enrichment and the sweet spot mode have not been proved. Therefore

the development efficiency is low in most areas. In order to further explore the prospect of exploration and development for the tight sandstone oil reservoir in Chang-8 Member

based on the previous study

the main controlling factors of reservoir formation were analyzed deeply in the study area by the data of core

logging

mud logging

analysis and testing

and combined with the production data of oil testing

production testing and horizontal wells. The results show that the accumulation of the tight sandstone oil reservoir Chang-8 Member is mainly controlled by four main control factors: high quality source rocks

excellent reservoir properties under favorable sedimentary microfacies

higher excess pressure difference and widely developed micro-fractures. And on this basis

five sweet spot modes of Chang-8 Member tight oil could be established

and the reasonable development modes are analyzed respectively according to these five modes

which indicated the direction for the efficient exploration and development of the tight oil reservoir in Chang-8 Member.