松辽盆地北部正反转构造与油气聚集

POSITIVE INVERTED STRUCTURES AND OILGAS ACCUMULATION IN NORTHERN SONGLIAO BASIN

所谓正反转构造是指早期深层为负向变形，晚期浅层反转为正向变形的一种叠合构造。松辽盆地北部目前发现２６个正反转构造，组合成４个反转构造带，均呈北东或北北东向。按其与早期正断层的成因关系，可划分为断层控制型与非断层控制型两大类。这些正反转构造自晚侏罗世以来，均经历了拉张裂陷→坳陷沉降→构造反转的三个发展阶段。构造演化的结果，纵向上正反转构造的幅度均小于拉张期的构造幅度；横向上由于反转期的挤压应力来于东部，正反转构造带的褶皱强度有由东向西减弱的规律。区内正反转构造具有面积较大、圈闭完整、直覆于凹陷之上的特征，十分有利于油气聚集与保存。根据烃源条件比较认为，区内长春岭、克山－大庆反转构造带是寻找油气田最有利的地区。

Positive inverted structures is a kind of compound structures. In the early stage, the deep layer is negative deformation;and in the late stage, the shallow layer reversed to forward deformation. There are 4 inverted structural belts,consisting of 26 positive inverted structures in the northern part of Songliao Basin,all show as eastnorthward.Based on the relation between the structures and the genesis of faults in early stage,the structures can be divided into 2 kinds, which are controlled by fault and non-fault respectively.The positive ininverted structures have gone through extension, depression,settlement and inverting since Late Jurassic. As the results of structural evolution,the relieves of positiV. inverted structures vertically is much less than that of structures in extension stage;and as the lateral extrusion stress in verting stage is from east, causes the fold intensityin positive inverted structural belts decreases from east to west.The positive inverted structures in the area havethe characteristics of large area,integrated trap, and locate above the depression, these.e good for oil migrationand accumulation. Through the comparison of hydrocarbon source conditions,the Changchunling,KeshanmDaqinginverted structural belts are regarded as the most favorable areas fo.the exploration of oil-gas fields.