Long ago’ people had known that oil and gas are fluid and organic minerals.The organic nature of oil and gas hints us where they might be,and the fluidity tells us how to search for them.The petroleum geology which records the human knowledge on the role of oil and gas distribution,however,had not developed around these two properties but along another way which was in keeping with the process of human cognition.People primarily knew the oil and gas starting from where they are now,for example,the earliest wells for oil or gas always drilled close by oil or gas seepage,and then,people found that oil and gas always distributed along a certain linear structure,or especially occurred in anticline structures as the anticlinal theory of petroleum accumulation was proposed;or within a tectoic province,known as petroliferous province.Aferwards there was a great leap in the process of human cognition when pepole differentiated the sedimentary basin from other tectonic unit in the petroliferous province,thus knowing that the basin is the only place suiting the formation of hydrocarbon.But the problems that what role would the fluidity of oil and gas play in pool formation,and what kind of principle would they follow,and how to utilize it for exploration still remain unsolved.Therefore,turning oil and gas exploration to basin merely shows that people have found the place where the oil and gas are being,but how to discover them is still remains discussing.
