柴达木盆地油气藏特征分析及对油气勘探的意义

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。

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

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-bearing 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 stu-died.