柴达木盆地油气藏特征分析及对油气勘探的意义

Analysis on reservoir characteristics of Qaidam Basin and its significance to petroleum exploration

对柴达木盆地19个油气田典型油气藏的详细解剖,油气藏具有6个特点:①油气层厚度薄,油气藏面积总体偏小;②油气藏油层物性相对较差;③古近系、新近系原油成熟度总体偏低;④油气藏类型丰富,构造、地层、岩性和复合型4大类油气藏均有发育;⑤以断层类油气藏为主,油气藏受断层的控制作用明显;⑥油气藏晚期破坏比较严重。在对油气藏特点系统分析的基础上,进一步指出:①柴达木盆地油气田分散,大油田少;②近源古构造最富集油气;③在继续加强构造油气藏勘探的同时,应注意地层、岩性油气藏的勘探;④深入研究断层对油气藏形成和分布的控制作用。

Six features of the reservoirs in Qaidam Basin is summarized through a detailed analysis of its 19 oil/ gas pools： （1） oil layers are thin and oil/gas-beating area is relatively small; （2） reservoir petrophysical properties are rather poor; （3） Tertiary oil maturity is relatively low as a whole; （4） pool types can involve structural, stratigraphic or lithological ones or a combination of them; （5） the distribution of oil and gas pools is controlled by faults and fault reservoirs are dominant; and （6） late destruction of oil/gas pools is more severe. By systematic study of all these characteristics, the writers further point out that （1） small and middle-sized oil fields is scattered in the basin, but larger ones are rarely found; （2） hydrocarbon accumulations are mainly distributed in the palaeo-structural traps near oil-generating center（ source rocks） ; （3） while continuously strengthening the exploration of structural oil and gas pools, the searching for stratigraphic and lithological oil and gas pools should also be stressed, and （4） the role of faults in the formation and distribution of oil and gas pools should be further studied.