祁连山北缘逆掩推覆带构造及成藏特征

青西油田位于祁连山北缘窟窿山逆掩推覆带的中部,其山前强烈褶皱并伴随一系列大型的逆掩断层,构造表现为断层向地表的前展式叠瓦状逆掩断裂带及其相关褶皱。为了搞清青西油田的构造特征和油气富集规律,以断裂构造剖析为主线,通过精细解释各级控油断层、构造细节、进行裂缝预测及控油作用研究,剖析了其油气分布的独特规律,指出在逆冲断层前缘形成的北东向撕裂断裂控制着有效裂缝发育带,是青西油田的高产区块。

Characteristics of Overthrust Nappe Structure and Its Hydrocarbon Accumulation in Northern Margin of Qilianshan Mountain

Qingxi field is located in middle of overthrust nappe in northern margin(Kulongshan)of Qilianshan mountain where in-tensive piedmont fold is associated with a series of huge overthrust fault structures which are characterized by advanced and im-bricate overthrust faulting toward surface and related folds.In order to structural feature and hydrocarbon enrichment,this paper presents in-depth analysis of the faulting structures and detailed interpretation of a variety of crude-controlled faults or structures,as well as fractural prediction and oil-controlled mechanism,showing its distinctive features of oil-gas distribution.It is concluded that the tear faulting of N-E trend shaped in overthrust fault front controls effective development of fractural belt,which could be high-yielding blocks in Qingxi field.