孤北斜坡带隐蔽圈闭成藏条件分析

孤北断层持续不均衡发育形成孤北斜坡带沟粱相间、陡缓变化的古地貌，古地貌控制了隐蔽圈闭的平面分布。由多旋回性构造运动造成沉积基准面的升降变化控制了隐蔽圈闭在斜坡带同一位置的垂向变化。斜坡带断层与砂岩发育带配置形成油气优势运移通道，它的走向决定着隐蔽圈闭的成藏。在古地貌和基准面旋回的控制下，孤北斜坡带隐蔽油气藏形成了平面上围绕孤岛凸起呈环带状分布，纵向上从孤北洼陷到孤岛凸起地层逐渐变新的展布格局。

Condition analysis of oil reservoir formation of the subtle traps in Gubei slope belt

Continuous disproportionate growth of Gubei fault formed the palaeogeomorphology of Gubei slope belt with groove alternating with roof and with abrupt and gentle change. The palaeogeomorphology decided the plane distribution of subtle trap. The tectonic movement with multi - cyclicity caused fluctuation change of sedimentary base level, which controlled the vertical variety of the subtle trap at same place at the slope belt. The disposition of the faults and sandstone development zones of the slope belt formed the predominant oil - gas migration pathway, whose strike decided whether the subtle traps can turn into subtle oil pool or not. Under the controlling of palaeogeomorphology and base level cycle, the subtle oil - gas pool in Gubei slope belt formed zonary distribution around Gubei uplift on plane and the time of the formations became more and more later from Gubei sag to Gudao uplift in vertical .